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Sample records for bioelectrical impedance phase

  1. Bioelectrical Impedance of Vectorial Analysis and Phase Angle in Adolescents.

    Science.gov (United States)

    Mathias-Genovez, Mariana G; Oliveira, Cristiana C; Camelo, José S; Del Ciampo, Luiz A; Monteiro, Jacqueline P

    2016-01-01

    Bioelectrical impedance can be interpreted by vector analysis using direct measures of the impedance vector; thus, collecting information about resistance (R), reactance (Xc), and phase angle (PA) makes it possible to classify an individual's nutritional status. The aim of this study was to investigate these values and construct bioelectrical references for healthy Brazilian adolescents. This is a cross-sectional study that included 567 healthy adolescents, aged 10 to 18 years. The bioelectrical impedance was performed to collect data for R and Xc. In addition, weight and height were also collected. The PA was calculated, and thereby the tolerance and confidence ellipses were constructed using specific software. For boys the mean vectors of 11 and 12 years, 12 and 13 years, 13 and 14 years, and 15 and 16 years were different from each other (p < 0.05). For girls the only mean vectors with significant differences were 11 and 12 years (p = 0.0071). The results differ from those in the literature, possibly due to ethnic differences in body composition. The present study provides an important tool for monitoring the nutritional status of adolescents of different ages, without previous knowledge of some anthropometric measures such as body weight.

  2. A bioelectrical impedance phase angle measuring system for assessment of nutritional status.

    Science.gov (United States)

    Zhang, Guanghao; Huo, Xiaolin; Wu, Changzhe; Zhang, Cheng; Duan, Zhongping

    2014-01-01

    Bioelectrical impedance phase angle has been recommended as a tool to assess nutrition state, but there are no measuring devices have been specially designed for hospital residents. In this study, a system was established for the measurement of bioelectrical impedance phase angle. The electrical composition, calculation method and measuring method of this system are presented in this paper. Experiments showed excellent performance of this system in measuring impedance made of resistors and capacitors. The designed system was also used to measure the bioelectrical impedance phase angle of both healthy subjects and patients with malnutrition, and the results demonstrated that the phase angle of patients with malnutrition is lower than that of healthy subjects (P nutritional status.

  3. The relationship between bioelectrical impedance phase angle and subjective global assessment in advanced colorectal cancer

    OpenAIRE

    Gupta, Digant; Lis, Christopher G; Dahlk, Sadie L; King, Jessica; Vashi, Pankaj G; Grutsch, James F; Lammersfeld, Carolyn A

    2008-01-01

    Abstract Background Bioelectrical Impedance (BIA) derived phase angle is increasingly being used as an objective indicator of nutritional status in advanced cancer. Subjective Global Assessment (SGA) is a subjective method of nutritional status. The objective of this study was to investigate the association between BIA derived phase angle and SGA in advanced colorectal cancer. Methods We evaluated a case series of 73 stages III and IV colorectal cancer patients. Patients were classified as ei...

  4. The bioelectrical impedance phase angle as an indicator of undernutrition and adverse clinical outcome in cardiac surgical patients

    NARCIS (Netherlands)

    Visser, Marlieke; van Venrooij, Lenny M. W.; Wanders, Dominique C. M.; de Vos, Rien; Wisselink, Willem; van Leeuwen, Paul A. M.; de Mol, Bas A. J. M.

    2012-01-01

    Background & aims: In cardiac surgical patients, undernutrition increases the risk of adverse clinical outcome. We investigated whether the bioelectrical impedance phase angle is an indicator of undernutrition and clinical outcome in cardiac surgery. Methods: In 325 cardiac surgical patients, we

  5. NOTE: Spatial dependence of the phase in localized bioelectrical impedance analysis

    Science.gov (United States)

    Shiffman, C. A.; Aaron, R.; Altman, A.

    2001-04-01

    The variety of phase functions, θ(z) = arctan X(z)/R(z), observed earlier on the thighs of healthy and seriously ill subjects via localized bioelectrical impedance analysis, can be represented by a model which combines realistic thigh shapes with homogeneous, axially symmetric conductivity tensors. While quantitative results depend sensitively on the way current is injected, it appears to be generally true that dθ/dz φz (and vice versa), where φr and φz are the phases of the radial and longitudinal conductivity components.

  6. Dynamic changes in bioelectrical impedance vector analysis and phase angle in acute decompensated heart failure.

    Science.gov (United States)

    Alves, Fernanda Donner; Souza, Gabriela Corrêa; Aliti, Graziella Badin; Rabelo-Silva, Eneida Rejane; Clausell, Nadine; Biolo, Andréia

    2015-01-01

    To evaluate whether changes in hydration status (reflecting fluid retention) would be detected by bioelectrical impedance vector analysis (BIVA) and phase angle during hospitalization for acute decompensated heart failure (ADHF) and after clinical stabilization. Patients admitted to ADHF were evaluated at admission, discharge and after clinical stabilization (3 mo after discharge) for dyspnea, weight, brain natriuretic peptide, bioelectrical impedance resistance, reactance, and phase angle. Generalized estimating equations and chi-square detected variations among the three time points of evaluation. Were included 57 patients: Mean age was 61 ± 13 y, 65% were male, LVEF was 25 ± 8%. During hospitalization there were improvements in clinical parameters and increase in resistance/height (from 250 ± 72 to 302 ± 59 Ohms/m, P < 0.001), reactance/height (from 24 ± 10 to 31 ± 9 Ohms/m, P < 0.001), and phase angle (from 5.3 ± 1.6 to 6 ± 1.6°, P = 0.007). From discharge to chronic stability, both clinical and BIVA parameters remained stable. At admission, 61% of patients had significant congestion by BIVA, and they lost more weight and had higher improvement in dyspnea during hospitalization (P < 0.05). At discharge, more patients were in the upper half of the graph (characterizing some degree of dehydration) while at chronic stability normal hydration status was more prevalent (P < 0.001). BIVA and phase angle were able to detect significant changes in hydration status during ADHF, which paralleled the clinical course of recompensation, both acutely and chronically. The classification of congestion by BIVA at admission identified patients with more pronounced changes in weight and dyspnea during compensation. Copyright © 2015 Elsevier Inc. All rights reserved.

  7. The relationship between bioelectrical impedance phase angle and subjective global assessment in advanced colorectal cancer

    Directory of Open Access Journals (Sweden)

    Grutsch James F

    2008-06-01

    Full Text Available Abstract Background Bioelectrical Impedance (BIA derived phase angle is increasingly being used as an objective indicator of nutritional status in advanced cancer. Subjective Global Assessment (SGA is a subjective method of nutritional status. The objective of this study was to investigate the association between BIA derived phase angle and SGA in advanced colorectal cancer. Methods We evaluated a case series of 73 stages III and IV colorectal cancer patients. Patients were classified as either well-nourished or malnourished using the SGA. BIA was conducted on all patients and phase angle was calculated. The correlation between phase angle and SGA was studied using Spearman correlation coefficient. Receiver Operating Characteristic curves were estimated using the non-parametric method to determine the optimal cut-off levels of phase angle. Results Well-nourished patients had a statistically significantly higher (p = 0.005 median phase angle score (6.12 as compared to those who were malnourished (5.18. The Spearman rank correlation coefficient between phase angle and SGA was found to be 0.33 (p = 0.004, suggesting better nutritional status with higher phase angle scores. A phase angle cut-off of 5.2 was 51.7% sensitive and 79.5% specific whereas a cut-off of 6.0 was 82.8% sensitive and 54.5% specific in detecting malnutrition. Interestingly, a phase angle cut-off of 5.9 demonstrated high diagnostic accuracy in males who had failed primary treatment for advanced colorectal cancer. Conclusion Our study suggests that bioimpedance phase angle is a potential nutritional indicator in advanced colorectal cancer. Further research is needed to elucidate the optimal cut-off levels of phase angle that can be incorporated into the oncology clinic for better nutritional evaluation and management.

  8. [Values of the phase angle by bioelectrical impedance; nutritional status and prognostic value].

    Science.gov (United States)

    Llames, L; Baldomero, V; Iglesias, M L; Rodota, L P

    2013-01-01

    Phase angle (PA) is the most established parameter from bioelectrical impedance analysis (BIA) for diagnosis of malnutrition and clinical prognosis, both associated with changes on cellular membrane integrity and alterations on fluids balance. PA expresses changes in quantity and quality of soft tissue mass (ie, cell membrane permeability and soft tissue hydration). A large body of clinical trials propose PA as a useful prognostic marker in clinical conditions like liver cirrhosis and breast, colon, pancreatic and lung cancer; positive association between PA and survival was also observed in surgical and HIV infected patients. Several authors suggest that PA can be an important tool in the evaluation of the clinical result or of the progression of the disease, and it can even be superior to other nutritional, biochemical or anthropometric indicators. Lack of reference values has limited its use in clinical and epidemiological situations. The purpose of this review is to describe PA reference values according to different clinical conditions as proposed in published scientific works. Copyright © AULA MEDICA EDICIONES 2013. Published by AULA MEDICA. All rights reserved.

  9. Bioelectrical impedance phase angle and subjective global assessment in detecting malnutrition among newly diagnosed head and neck cancer patients.

    Science.gov (United States)

    Małecka-Massalska, Teresa; Mlak, Radoslaw; Smolen, Agata; Morshed, Kamal

    2016-05-01

    Malnutrition, which can be determined by subjective and objective methods, has a high prevalence in head and neck cancer patients. Subjective Global Assessment is a subjective method of nutritional status evaluation. Phase angle, determined by bioelectrical impedance analysis, is proposed as an objective nutritional marker in various disease conditions. The study was conducted to investigate the association between phase angle and Subjective Global Assessment to validate the determination of the nutrition status in adult patients with head and neck cancer. In a prospective cohort study, patients were classified as either well-nourished or malnourished using the Subjective Global Assessment. Phase angle measured by bioelectrical impedance analysis was planned in 75 naive patients with histologically confirmed head and neck cancer. Receiver operating characteristic curves were estimated using the non-parametric method to determine the optimal cut-off level of phase angle. The study was conducted on a cohort population of 75 patients. Well-nourished patients (n = 45) had a statistically significantly higher (p = 0.005) median phase angle score (5.25º) as compared to those who were malnourished (4.73º) (n = 30). A phase angle cut-off of 4.73 was 80 % sensitive and 56.7 % specific in detecting malnutrition diagnosed by SGA in these populations. Phase angle is considered to be a nutritional indicator in patients with head and neck cancer in detecting malnutrition. Further observations are needed to calculate survival, and validate the prognostic significance of phase angle. For future studies, it is important to indicate the specificity of the PA in comparison to SGA measurement.

  10. Body fat estimation using bioelectrical impedance.

    Science.gov (United States)

    Shaikh, M G; Crabtree, N J; Shaw, N J; Kirk, J M W

    2007-01-01

    Although childhood obesity is a major problem, routine assessment methods do not reflect fat mass. Body mass index, which is most commonly used, gives an indication of weight for height and not a degree of adiposity. Bioelectrical impedance and dual-energy X-ray absorptiometry (DEXA) were used in a group of obese children to assess body fat. Comparison between DEXA and commercial bioelectrical impedance scales in 46 children showed a highly significant correlation (R = 0.944, p bioelectrical impedance was 2.4 kg lower compared to measurement using DEXA. These bioelectrical scales may prove useful in the management of childhood obesity as they are able to provide important clinical information regarding fat mass and adiposity. Copyright 2007 S. Karger AG, Basel.

  11. Bioelectrical Impedance and Body Composition Assessment

    Science.gov (United States)

    Martino, Mike

    2006-01-01

    This article discusses field tests that can be used in physical education programs. The most common field tests are anthropometric measurements, which include body mass index (BMI), girth measurements, and skinfold testing. Another field test that is gaining popularity is bioelectrical impedance analysis (BIA). Each method has particular strengths…

  12. Bioelectrical impedance phase angle relates to function, disease severity and prognosis in stable chronic obstructive pulmonary disease.

    Science.gov (United States)

    Maddocks, Matthew; Kon, Samantha S C; Jones, Sarah E; Canavan, Jane L; Nolan, Claire M; Higginson, Irene J; Gao, Wei; Polkey, Michael I; Man, William D-C

    2015-12-01

    Bioelectrical impedance analysis (BIA) provides a simple method to assess changes in body composition. Raw BIA variables such as phase angle provide direct information on cellular mass and integrity, without the assumptions inherent in estimating body compartments, e.g. fat-free mass (FFM). Phase angle is a strong functional and prognostic marker in many disease states, but data in COPD are lacking. Our aims were to describe the measurement of phase angle in patients with stable COPD and determine the construct and discriminate validity of phase angle by assessing its relationship with established markers of function, disease severity and prognosis. 502 outpatients with stable COPD were studied. Phase angle and FFM by BIA, quadriceps strength (QMVC), 4-m gait speed (4MGS), 5 sit-to-stand time (5STS), incremental shuttle walk (ISW), and composite prognostic indices (ADO, iBODE) were measured. Patients were stratified into normal and low phase angle and FFM index. Phase angle correlated positively with FFM and functional outcomes (r = 0.35-0.66, p < 0.001) and negatively with prognostic indices (r = -0.35 to -0.48, p < 0.001). In regression models, phase angle was independently associated with ISW, ADO and iBODE whereas FFM was removed. One hundred and seventy patients (33.9% [95% CI, 29.9-38.1]) had a low phase angle. Phenotypic characteristics included lower QMVC, ISW, and 4MGS, higher 5STS, ADO and iBODE scores, and more exacerbations and hospital days in past year. The proportion of patients to have died was significantly higher in patients with low phase angle compared to those with normal phase angle (8.2% versus 3.6%, p = 0.02). Phase angle relates to markers of function, disease severity and prognosis in patients with COPD. As a directly measured variable, phase angle offers more useful information than fat-free mass indices. Copyright © 2015 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.

  13. Phase angle assessment by bioelectrical impedance analysis and its predictive value for malnutrition risk in hospitalized geriatric patients.

    Science.gov (United States)

    Varan, Hacer Dogan; Bolayir, Basak; Kara, Ozgur; Arik, Gunes; Kizilarslanoglu, Muhammet Cemal; Kilic, Mustafa Kemal; Sumer, Fatih; Kuyumcu, Mehmet Emin; Yesil, Yusuf; Yavuz, Burcu Balam; Halil, Meltem; Cankurtaran, Mustafa

    2016-12-01

    Phase angle (PhA) value determined by bioelectrical impedance analysis (BIA) is an indicator of cell membrane damage and body cell mass. Recent studies have shown that low PhA value is associated with increased nutritional risk in various group of patients. However, there have been only a few studies performed globally assessing the relationship between nutritional risk and PhA in hospitalized geriatric patients. The aim of the study is to evaluate the predictive value of the PhA for malnutrition risk in hospitalized geriatric patients. One hundred and twenty-two hospitalized geriatric patients were included in this cross-sectional study. Comprehensive geriatric assessment tests and BIA measurements were performed within the first 48 h after admission. Nutritional risk state of the patients was determined with NRS-2002. Phase angle values of the patients with malnutrition risk were compared with the patients that did not have the same risk. The independent variables for predicting malnutrition risk were determined. SPSS version 15 was utilized for the statistical analyzes. The patients with malnutrition risk had significantly lower phase angle values than the patients without malnutrition risk (p = 0.003). ROC curve analysis suggested that the optimum PhA cut-off point for malnutrition risk was 4.7° with 79.6 % sensitivity, 64.6 % specificity, 73.9 % positive predictive value, and 73.9 % negative predictive value. BMI, prealbumin, PhA, and Mini Mental State Examination Test scores were the independent variables for predicting malnutrition risk. PhA can be a useful, independent indicator for predicting malnutrition risk in hospitalized geriatric patients.

  14. Bioelectrical impedance analysis--part I

    DEFF Research Database (Denmark)

    Kyle, Ursula G; Bosaeus, Ingvar; De Lorenzo, Antonio D

    2004-01-01

    The use of bioelectrical impedance analysis (BIA) is widespread both in healthy subjects and patients, but suffers from a lack of standardized method and quality control procedures. BIA allows the determination of the fat-free mass (FFM) and total body water (TBW) in subjects without significant...... of the estimate. The determination of changes in body cell mass (BCM), extra cellular (ECW) and intra cellular water (ICW) requires further research using a valid model that guarantees that ECW changes do not corrupt the ICW. The use of segmental-BIA, multifrequency BIA, or bioelectrical spectroscopy in altered...

  15. The Phase Angle of the Bioelectrical Impedance Analysis as Predictor of Post-Bariatric Weight Loss Outcome.

    Science.gov (United States)

    Vassilev, Georgi; Hasenberg, Till; Krammer, Johannes; Kienle, Peter; Ronellenfitsch, Ulrich; Otto, Mirko

    2017-03-01

    Bariatric surgery is proven to be the most effective therapy for obesity. However, the targeted weight reduction is not always achieved. Reliable predictors for postoperative success are rare. Also, most available predictors, such as gender and socioeconomic status, cannot be influenced. The aim of the study was to assess the reliability of the phase angle (PhA) as a predictor of weight reduction and body composition after bariatric surgery. One hundred seventy-three patients (127 with Roux-en-Y gastric bypass and 46 with sleeve gastrectomy), treated between January 2004 and December 2012, were included into this prospective trial. Bioelectrical impedance analysis (BIA) was performed before and five times within the first year after the operation. Correlation between excess weight loss (EWL) was calculated using Pearson's correlation coefficient and a receiver operating characteristic (ROC) curve. The average weight loss was significant with a total weight loss of 30.1 %, while the PhA did not show any significant decrease during the first 12 months after surgery. The correlation between the preoperative PhA and the postoperative EWL was significant after 6 weeks and after 6, 9, and 12 months. The ROC curve has an area of 0.7. The best point of the curve is a PhA of 3.9° with a sensitivity of 81 % and a specificity of 54 %. PhA may be a useful predictor of EWL after bariatric surgery, and a PhA of 3.9° was calculated as the most suitable cut-off for a successful operation.

  16. Segmental bioelectrical impedance analysis: an update.

    Science.gov (United States)

    Ward, Leigh C

    2012-09-01

    Bioelectrical impedance analysis is a popular, noninvasive and practical method for assessment of body composition. The last decade has seen the development of impedance analyzers designed to assess the composition of body segments as well as the whole body. This review outlines the theoretical basis for segmental impedance analysis, validity and use in practice. Segmental impedance analysis tends to underestimate fat-free mass and overestimate fat mass when compared to reference techniques, although the magnitude of these differences can be small. Performance is improved with population-specific prediction equations; algorithms in-built into instrument firmware should not be relied upon. Prediction of whole-body composition from the sum of the individual segments, although theoretically preferable, shows little advantage over whole body wrist to ankle impedance approaches. Prediction of appendicular skeletal muscle mass, although promising, requires further research. The use of measured impedance data directly as indices of composition, rather than for prediction, has not found extensive application in nutritional research despite its success in other fields. Segmental bioimpedance techniques have advanced substantially in recent years due to availability of simple-to-use analyzers and simplified measurement protocols. The method has been well validated and increasingly adopted in nutritional and clinical practice. Segmental impedance, like conventional whole body impedance approaches, provides indirect prediction of body composition whose accuracy is yet to achieve that of reference techniques such as magnetic reference imaging. This lack of accuracy, however, is outweighed by the method's practicality of use in many settings.

  17. Bioelectrical Impedance Assessment of Wound Healing

    Science.gov (United States)

    Lukaski, Henry C; Moore, Micheal

    2012-01-01

    Objective assessment of wound healing is fundamental to evaluate therapeutic and nutritional interventions and to identify complications. Despite availability of many techniques to monitor wounds, there is a need for a safe, practical, accurate, and effective method. A new method is localized bioelectrical impedance analysis (BIA) that noninvasively provides information describing cellular changes that occur during healing and signal complications to wound healing. This article describes the theory and application of localized BIA and provides examples of its use among patients with lower leg wounds. This promising method may afford clinicians a novel technique for routine monitoring of interventions and surveillance of wounds. PMID:22401341

  18. Bioelectrical impedance analysis for bovine milk: Preliminary results

    Science.gov (United States)

    Bertemes-Filho, P.; Valicheski, R.; Pereira, R. M.; Paterno, A. S.

    2010-04-01

    This work reports the investigation and analysis of bovine milk quality by using biological impedance measurements using electrical impedance spectroscopy (EIS). The samples were distinguished by a first chemical analysis using Fourier transform midinfrared spectroscopy (FTIR) and flow citometry. A set of milk samples (100ml each) obtained from 17 different cows in lactation with and without mastitis were analyzed with the proposed technique using EIS. The samples were adulterated by adding distilled water and hydrogen peroxide in a controlled manner. FTIR spectroscopy and flow cytometry were performed, and impedance measurements were made in a frequency range from 500Hz up to 1MHz with an implemented EIS system. The system's phase shift was compensated by measuring saline solutions. It was possible to show that the results obtained with the Bioelectrical Impedance Analysis (BIA) technique may detect changes in the milk caused by mastitis and the presence of water and hydrogen peroxide in the bovine milk.

  19. Analysis of concordance between the bioelectrical impedance vector analysis and the bioelectrical impedance spectroscopy in haemodialysis patients.

    Science.gov (United States)

    Teruel-Briones, José L; Fernández-Lucas, Milagros; Ruiz-Roso, Gloria; Sánchez-Ramírez, Humberto; Rivera-Gorrin, Maite; Gomis-Couto, Antonio; Rodríguez-Mendiola, Nuria; Quereda, Carlos

    2012-05-14

    The values of body composition provided by the two most commonly used bioelectrical impedance systems in Spain, single-frequency bioelectrical impedance vector analysis (SF-BIVA) and multi-frequency bioelectrical impedance spectroscopy (MF-BIS) are different and not comparable. Analyse whether the inter-method variability is due to bioelectrical variables measured by the different monitors, or rather due to the equations used to calculate body volume and mass. Another objective was to determine whether, despite the inter-method variability, the classification of hydration status by the two methods is consistent. Bioelectrical impedance was measured by SF-BIVA and MF-BIS immediately before a dialysis session in 54 patients on haemodialysis. In 38 patients, the study was repeated by SF-BIVA at the end of the same dialysis session. Resistance and phase angle values provided by the two monitors at a frequency of 50kHz were consistent. For resistance, variability was 1.3% and the intra-class correlation coefficient was 0.99. For phase angle, variability and the intra-class correlation coefficient were 11.5% and 0.92, respectively. The volume values for total body water, extracellular water, fat mass and body cell mass were biased, with a level of variability that would not be acceptable in clinical practice. The intra-class correlation coefficient also suggested a poor level of agreement. SF-BIVA systems define overhydration or dehydration as a vector below or above the tolerance ellipse of 75% on the longitudinal axis. MF-BIS uses two criteria for pre-dialysis hyper-hydration: overhydration (OH) greater than 2.5 litres, or greater than 15% of extracellular water. The degree of equivalence with the results of the SF-BIVA monitor was better with the second criterion (kappa: 0.81, excellent agreement) than with the first one (kappa: 0.71, acceptable agreement). The MF-BIS system defines post-dialysis normal hydration as a difference between OH and ultrafiltratation volume

  20. Bioelectrical impedance analysis. What does it measure?

    Science.gov (United States)

    Schoeller, D. A.

    2000-01-01

    Bioelectrical impedance analysis (BIA) has been proposed for measuring fat-free mass, total body water, percent fat, body cell mass, intracellular water, and extracellular water: a veritable laboratory in a box. Although it is unlikely that BIA is quite this versatile, correlations have been demonstrated between BIA and all of these body compartments. At the same time, it is known that all of the compartments are correlated among themselves. Because of this, it is difficult to determine whether BIA is specific for any or all of these compartments. To investigate this question, we induced acute changes in total body water and its compartments over a 3-h period. Using this approach, we demonstrated that multifrequency BIA, using the Cole-Cole model to calculate the zero frequency and infinite frequency resistance, measures extracellular and intracellular water.

  1. A low phase angle measured with bioelectrical impedance analysis is associated with osteoporosis and is a risk factor for osteoporosis in community-dwelling people: the Yakumo study.

    Science.gov (United States)

    Tanaka, Satoshi; Ando, Kei; Kobayashi, Kazuyoshi; Hida, Tetsuro; Ito, Kenyu; Tsushima, Mikito; Morozumi, Masayoshi; Machino, Masaaki; Ota, Kyotaro; Seki, Taisuke; Ishiguro, Naoki; Hasegawa, Yukiharu; Imagama, Shiro

    2018-04-05

    Although the phase angle has been reported to be related to predictive factors and therapeutic effects in various diseases, its relation with osteoporosis is unclear. In our large prospective survey of community-dwelling people, a low phase angle was related with osteoporosis, and it could be a predictor of osteoporosis. The phase angle measured with bioelectrical impedance analysis (BIA) is one of the clinically important impedance parameters, and it is a predictor of prognosis and mortality for several diseases. The present cross-sectional study aimed to elucidate the association between osteoporosis and variables measured with BIA, including the phase angle. The study included 307 participants from an annual health checkup. All participants underwent measurement of bone status by quantitative ultrasound and body composition by BIA. Osteoporosis was diagnosed according to the WHO classification, and statistical comparisons were conducted between normal individuals and osteoporosis patients. Age, proteins, minerals, and the phase angle were significantly different between normal individuals and osteoporosis patients (p < 0.001). Furthermore, after controlling for age and sex, proteins, minerals, and the phase angle were significantly lower in osteoporosis patients than those in normal individuals (p < 0.001). In multivariate logistic regression analysis, older age and a low phase angle were risk factors for osteoporosis. Additionally, multiple regression analysis showed that age, sex, proteins, minerals, and the appendicular skeletal muscle index were significantly related to the phase angle. The phase angle is a predictor of osteoporosis, which is unaffected by age and sex, and a lower phase angle is associated with greater probability of osteoporosis. The phase angle can be easily measured, and osteoporosis can be confirmed even at home. This may facilitate early diagnosis and treatment, which may be useful for preventing diseases related to osteoporosis.

  2. The bioelectrical impedance vector migration in healthy infants

    OpenAIRE

    L'Abee, Carianne; Poorts-Borger, Petra H.; Gorter, Erna H. G. M.; Piccoli, Antonio; Stolk, Ronald P.; Sauer, Pieter J. J.

    2010-01-01

    Background & aims: Detecting young children with high amount of body fat is important to intervene in the development of obesity. The aim of this study is to gain inside in the bioelectrical impedance vector analysis in healthy infants. Methods: Repeated measurements of whole body reactance and resistance were assessed, using a 50 kHz frequency bioelectrical impedance analysis, in 51 boys and 62 girls during infancy. Bivariate vector analysis, which can be used to determine tissue hydration a...

  3. The value of bioelectrical impedance analysis and phase angle in the evaluation of malnutrition and quality of life in cancer patients--a comprehensive review.

    Science.gov (United States)

    Grundmann, O; Yoon, S L; Williams, J J

    2015-12-01

    Bioelectrical impedance analysis (BIA) and especially its derived parameter phase angle have been widely used in different populations. The variability of BIA measures has often been cited as a major limitation for its clinical use in evaluating nutritional status and overall health of patients. Cancer patients often present with malnourishment and cachexia, which complicate the course of treatment and affect outcomes. PubMed, CINAHL, EBSCO and Cochrane Library have been searched for relevant publications in English for BIA in cancer patients. Out of 197 total results, 27 original research articles related to BIA measures in cancer patients were included in this review. Studies indicate that the use of BIA and phase angle measures can benefit in the clinical management of cancer patients in multiple ways: in the prevention; diagnosis; prognosis; and outcomes related to treatments that affect nutritional and overall health status. Phase angle and fat-free mass measures were most commonly evaluated and correlated with nutritional status and survival rate. One limitation of BIA measures is the high interpatient variability which requires careful interpretation of results in the context of the individual patient rather than comparison with population data. The BIA and phase angle provide practitioners for the evaluation of nutritional and overall health status in cancer patients with a convenient and non-invasive technique and should be encouraged.

  4. Bioelectrical impedance vector analysis, phase-angle assessment and relationship with malnutrition risk in a cohort of frail older hospital patients in the United Kingdom.

    Science.gov (United States)

    Slee, Adrian; Birc, Deborah; Stokoe, David

    2015-01-01

    Bioelectrical impedance vector analysis (BIVA) and phase angle (PA) have been shown previously to indicate relative nutritional status in patients. The aim of this study was to investigate the application of BIVA and PA assessments in a cohort of frail older hospital patients and compare these assessments with malnutrition risk screening by MUST (Malnutrition Universal Screening Tool), and the MNA-SF(®) (Mini-Nutritional Assessment-Short Form). Sixty-nine patients (n = 44 men; n = 25 women; age 82.1 ± 7.6 y [range 62-96 y]; body mass index 25.8 ± 5.4 kg/m(2) [range 16.6-45.1 kg/m(2)]) were recruited from hospital wards specializing in the care of frail older individuals from the United Kingdom. Bioelectrical impedance assessment was performed at 50 khz frequency, BIVA was performed using raw impedance data, PA was calculated, and data were compared against reference population groups. Patients were categorized by malnutrition risk by MUST and MNA-SF. BIVA indicated that the men and women in the study were significantly different from reference population groups (P < 0.0001), with a noticeable reduced capacitive reactance (xC) component. The group mean PA was 4.6° ± 1.1° (2.4°-9.2°). The mean PA for men was 4.7° ± 1.3° (2.4°-9.2°), and for women it was 4.5° ± 0.7° (2.8-6.0°). Group PA correlated with MNA-SF score (P = 0.05). MUST categorized patients predominantly at low risk for malnutrition (80%); whereas MNA-SF was at risk (46%) and malnourished (45%). The significant reduction in xC component and PA is consistent with other studies and is indicative of a reduced body cell mass and nutritional status with aging and illness. The general trend in MNA-SF scoring was more consistent with these patterns as a group; but requires clarification in larger cohorts. Future studies are necessary with an aim to improve and optimize care of frail older people. Copyright © 2015 Elsevier Inc. All rights reserved.

  5. Feasibility of bioelectrical impedance spectroscopy measurement before and after thoracentesis.

    Science.gov (United States)

    Zink, Matthias Daniel; Weyer, Sören; Pauly, Karolin; Napp, Andreas; Dreher, Michael; Leonhardt, Steffen; Marx, Nikolaus; Schauerte, Patrick; Mischke, Karl

    2015-01-01

    Bioelectrical impedance spectroscopy is applied to measure changes in tissue composition. The aim of this study was to evaluate its feasibility in measuring the fluid shift after thoracentesis in patients with pleural effusion. 45 participants (21 with pleural effusion and 24 healthy subjects) were included. Bioelectrical impedance was analyzed for "Transthoracic," "Foot to Foot," "Foot to Hand," and "Hand to Hand" vectors in low and high frequency domain before and after thoracentesis. Healthy subjects were measured at a single time point. The mean volume of removed pleural effusion was 1169 ± 513 mL. The "Foot to Foot," "Hand to Hand," and "Foot to Hand" vector indicated a trend for increased bioelectrical impedance after thoracentesis. Values for the low frequency domain in the "Transthoracic" vector increased significantly (P impedance change in the low frequency domain using the "Foot to Hand" vector (r = -0.7). Bioelectrical impedance changes in correlation with the thoracic fluid level. It was feasible to monitor significant fluid shifts and loss after thoracentesis in the "Transthoracic" vector by means of bioelectrical impedance spectroscopy. The trial is registered with Registration Numbers IRB EK206/11 and NCT01778270.

  6. Bioelectrical impedance phase angle in clinical practice: implications for prognosis in stage IIIB and IV non-small cell lung cancer

    Directory of Open Access Journals (Sweden)

    Grutsch James F

    2009-01-01

    Full Text Available Abstract Background A frequent manifestation of advanced lung cancer is malnutrition, timely identification and treatment of which can lead to improved patient outcomes. Bioelectrical impedance analysis (BIA is an easy-to-use and non-invasive technique to evaluate changes in body composition and nutritional status. We investigated the prognostic role of BIA-derived phase angle in advanced non-small cell lung cancer (NSCLC. Methods A case series of 165 stages IIIB and IV NSCLC patients treated at our center. The Kaplan Meier method was used to calculate survival. Cox proportional hazard models were constructed to evaluate the prognostic effect of phase angle, independent of stage at diagnosis and prior treatment history. Results 93 were males and 72 females. 61 had stage IIIB disease at diagnosis while 104 had stage IV. The median phase angle was 5.3 degrees (range = 2.9 – 8. Patients with phase angle 5.3 had 12.4 months (95% CI: 10.5 to 18.7; n = 84; (p = 0.02. After adjusting for age, stage at diagnosis and prior treatment history we found that every one degree increase in phase angle was associated with a relative risk of 0.79 (95% CI: 0.64 to 0.97, P = 0.02. Conclusion We found BIA-derived phase angle to be an independent prognostic indicator in patients with stage IIIB and IV NSCLC. Nutritional interventions targeted at improving phase angle could potentially lead to an improved survival in patients with advanced NSCLC.

  7. Bioelectrical Impedance Vector Analysis and Muscular Fitness in Healthy Men

    Directory of Open Access Journals (Sweden)

    Fernando Rodríguez-Rodríguez

    2016-07-01

    Full Text Available Muscle strength can define the general muscular fitness (MF measurable through hand-grip strength (HG, which is a factor that relates to the health of people of different ages. In this study we evaluated the muscle strength together with a bioimpedance electric analysis in 223 healthy Colombian adult subjects. The bioelectrical impedance vector analysis (BIVA was conducted to determine the resistance (R, reactance (Xc and phase angle (PhA. We classified the subjects into three groups (for tertiles, obtaining lower values of R and Xc in subjects with lower HG, plus a high correlation between PhA and HG. An increase in the level of PhA is associated with a high level of MF in a sample of healthy Latin American adult men. The BIVA’s parameters and PhA are a potentially effective preventive measure to be integrated into routine screening in the clinical setting.

  8. Bioelectrical Impedance Vector Analysis and Muscular Fitness in Healthy Men.

    Science.gov (United States)

    Rodríguez-Rodríguez, Fernando; Cristi-Montero, Carlos; González-Ruíz, Katherine; Correa-Bautista, Jorge Enrique; Ramírez-Vélez, Robinson

    2016-07-02

    Muscle strength can define the general muscular fitness (MF) measurable through hand-grip strength (HG), which is a factor that relates to the health of people of different ages. In this study we evaluated the muscle strength together with a bioimpedance electric analysis in 223 healthy Colombian adult subjects. The bioelectrical impedance vector analysis (BIVA) was conducted to determine the resistance (R), reactance (Xc) and phase angle (PhA). We classified the subjects into three groups (for tertiles), obtaining lower values of R and Xc in subjects with lower HG, plus a high correlation between PhA and HG. An increase in the level of PhA is associated with a high level of MF in a sample of healthy Latin American adult men. The BIVA's parameters and PhA are a potentially effective preventive measure to be integrated into routine screening in the clinical setting.

  9. Anisotropic bioelectrical impedance determination of subcutaneous fat thickness

    Science.gov (United States)

    Hernández-Becerra, P. A. I.; Delgadillo-Holtfort, I.; Balleza-Ordaz, M.; Huerta-Franco, M. R.; Vargas-Luna, M.

    2014-11-01

    Preliminary results have shown that bioelectrical impedance measurements performed on different parts of the human body strongly depend upon the subcutaneous fat of the considered region. In this work, a method for the determination of subcutaneous fat thickness is explored. Within this method the measurement of the bioelectrical impedance response of the fat-muscle system, both along the direction defined by the muscle fibers and along the corresponding perpendicular direction, are performed. Measurements have been carried out on human female and male subjects of ages around 25 years old at the region of the biceps. Correlation has been performed with skinfold caliper measurements.

  10. Bioelectrical Impedance Methods for Noninvasive Health Monitoring: A Review

    Science.gov (United States)

    Bera, Tushar Kanti

    2014-01-01

    Under the alternating electrical excitation, biological tissues produce a complex electrical impedance which depends on tissue composition, structures, health status, and applied signal frequency, and hence the bioelectrical impedance methods can be utilized for noninvasive tissue characterization. As the impedance responses of these tissue parameters vary with frequencies of the applied signal, the impedance analysis conducted over a wide frequency band provides more information about the tissue interiors which help us to better understand the biological tissues anatomy, physiology, and pathology. Over past few decades, a number of impedance based noninvasive tissue characterization techniques such as bioelectrical impedance analysis (BIA), electrical impedance spectroscopy (EIS), electrical impedance plethysmography (IPG), impedance cardiography (ICG), and electrical impedance tomography (EIT) have been proposed and a lot of research works have been conducted on these methods for noninvasive tissue characterization and disease diagnosis. In this paper BIA, EIS, IPG, ICG, and EIT techniques and their applications in different fields have been reviewed and technical perspective of these impedance methods has been presented. The working principles, applications, merits, and demerits of these methods has been discussed in detail along with their other technical issues followed by present status and future trends. PMID:27006932

  11. Relationship between bioelectrical impedance-derived estimates of ...

    African Journals Online (AJOL)

    Measurements of basal metabolic rate (BMR) and body composition parameters represent an important tool for preventing obesity. This investigation examined the relationships between bioelectrical impedance-derived estimates of BMR and various body composition parameters, including age, body mass index, ...

  12. The bioelectrical impedance vector migration in healthy infants

    NARCIS (Netherlands)

    L'Abee, Carianne; Poorts-Borger, Petra H.; Gorter, Erna H. G. M.; Piccoli, Antonio; Stolk, Ronald P.; Sauer, Pieter J. J.

    Background & aims: Detecting young children with high amount of body fat is important to intervene in the development of obesity. The aim of this study is to gain inside in the bioelectrical impedance vector analysis in healthy infants. Methods: Repeated measurements of whole body reactance and

  13. BIOELECTRICAL IMPEDANCE VECTOR ANALYSIS IDENTIFIES SARCOPENIA IN NURSING HOME RESIDENTS

    Science.gov (United States)

    Loss of muscle mass and water shifts between body compartments are contributing factors to frailty in the elderly. The body composition changes are especially pronounced in institutionalized elderly. We investigated the ability of single-frequency bioelectrical impedance analysis (BIA) to identify b...

  14. Bioelectrical impedance vector analysis (BIVA) for measuring the hydration status in young elite synchronized swimmers.

    Science.gov (United States)

    Carrasco-Marginet, Marta; Castizo-Olier, Jorge; Rodríguez-Zamora, Lara; Iglesias, Xavier; Rodríguez, Ferran A; Chaverri, Diego; Brotons, Daniel; Irurtia, Alfredo

    2017-01-01

    The assessment of body hydration is a complex process, and no measurement is valid for all situations. Bioelectrical impedance vector analysis (BIVA) has emerged as a relatively novel technique for assessing hydration status in sports. We applied BIVA a) to determine hydration changes evoked by an intense synchronized swimming (SS) training session; b) to characterize the sample of young elite swimmers in relation with a nonathletic reference population; and c) to generate its 50%, 75% and 95% percentiles of the bioelectrical variables. Forty-nine elite SS female swimmers of two age categories, comen (Co: 13.9 ± 0.9 years, n = 34) and junior (Jr: 16.3 ± 0.6 years, n = 15), performed a long, high intensity training session. Body mass (BM) and bioelectrical variables (R, resistance; Xc, reactance; PA, phase angle; and Z, impedance module) were assessed pre- and post-training. BIVA was used to characterize 1) the distribution pattern of the bioelectrical vector (BIA vector) for both age groups, and 2) pre- to post-training BIA vector migration. Bioelectrical variables were also correlated with BM change values. Most swimmers were mostly located outside the 75% and some beyond the 95% percentile of the bioelectrical tolerance ellipses of the general population. The BIA vector showed statistically significant differences in both Co (T2 = 134.7, p = 0.0001) and Jr (T2 = 126.2, p bioelectrically different (T2 = 17.6, p bioelectrical variables. BIVA showed specific bioelectrical characteristics in young elite SS athletes. Considering the decrease in BM and the migration of the BIA vector, we conclude that the homeostatic hydration status of these young elite female swimmers was affected by the execution of intense training sessions. From a methodological perspective, BIVA appears to be sensitive enough to detect subtle hydration changes, but further research is needed to ensure its validity and reliability. Moreover, these findings highlight the importance of ensuring

  15. Experimental verification of depolarization effects in bioelectrical impedance measurement.

    Science.gov (United States)

    Chen, Xiaoyan; Lv, Xinqiang; Du, Meng

    2014-01-01

    The electrode polarization effects on bioelectrical impedance measurement at low-frequency cannot be ignored. In this paper, the bioelectrical data of mice livers are measured to specify the polarization effects on the bio-impedance measurement data. We firstly introduce the measurement system and methodology. Using the depolarization method, the corrected results are obtained. Besides, the specific effects of electrode polarization on bio-impedance measurement results are investigated using comparative analysis of the previous and posterior correction results from dielectric spectroscopy, Cole-Cole plot, conductivity and spectroscopy of dissipation tangent. Experimental results show that electrode polarization has a significant influence on the characteristic parameters of mouse liver tissues. To be specific, we see a low-frequency limit resistance R0 increase by 19.29%, a reactance peak XP increase by 8.50%, a low-frequency limit conductivity Kl decrease by 17.65% and a dissipation peak tangent decrease by 160%.

  16. Associations between bioelectrical impedance parameters and cardiovascular events in chronic dialysis patients.

    Science.gov (United States)

    de Araujo Antunes, Aline; Vannini, Francieli Delatim; de Arruda Silveira, Liciana Vaz; Barretti, Pasqual; Martin, Luis Cuadrado; Caramori, Jacqueline Costa Teixeira

    2013-10-01

    Malnutrition and fluid overload contribute to the poor cardiovascular prognosis of dialysis patients. Since bioelectrical impedance analysis is an option for the evaluation of body composition and for the monitoring of hydration state, it may assist in the identification of subjects at high cardiovascular risk. The objective of this study was to evaluate the association between bioelectrical impedance parameters and cardiovascular events. The association between bioelectrical impedance parameters and fatal and non-fatal cardiovascular outcome was evaluated in 145 dialysis patients. The mean age of the population studied was 54.9 ± 15.4 years, 49.7 % were males, and 35.9 % had diabetes. Forty (27.6 %) patients developed cardiovascular events during the 16 months (8; 32) of follow-up. Comparison of patients with and without cardiovascular events revealed higher extracellular mass/body cell mass (ECM/BCM) and extracellular water/total body water ratios and higher C-reactive protein levels in the former. Survival analysis showed that an ECM/BCM ratio >1.2 and a phase angle bioelectrical impedance for the clinical assessment of dialysis patients.

  17. Bioelectrical impedance analysis during pregnancy and neonatal birth weight.

    Science.gov (United States)

    Ghezzi, F; Franchi, M; Balestreri, D; Lischetti, B; Mele, M C; Alberico, S; Bolis, P

    2001-10-01

    To generate reference ranges for bioelectrical impedance indices throughout pregnancy and to investigate whether a relationship exists between these indices and the neonatal birth weight. Pregnant women with a singleton gestation, gestational age lower than 12 weeks, and absence of medical diseases before pregnancy were enrolled. Patients with pregnancy complications, such as hypertensive disorders, diabetes, and antiphospholipides syndrome were excluded. Antrophometric maternal parameters and bioelectrical impedance measurements were performed during the first, second, third trimester of pregnancy, at delivery and 60 days after delivery. Height(2)/resistance (cm(2)/Omega) and height(2)/reactance (cm(2)/Omega) were utilized to estimate the total and extracellular body water amounts, respectively. Spearman rank correlations and cox proportional hazard modelling were used for statistical purposes. 169 patients completed all measurements. Total and extracellular water amounts significantly increase as pregnancy advances and return to the pre-pregnancy values within 60 days after delivery. After adjustment for gestational age at delivery, fetal sex, and smoking habits, height(2)/resistance at 25 weeks (hazard=1.04, 95% confidence interval (CI) 1.02-1.06, Pweight. We have provided reference ranges for bioimpedance analysis during pregnancy, an easy, fast and non invasive method to estimate the body water composition during pregnancy. Bioelectrical impedance indices during the second trimester of pregnancy are independently related to the birth weight.

  18. Bioelectrical impedance analysis of bovine milk fat

    International Nuclear Information System (INIS)

    Veiga, E A; Bertemes-Filho, P

    2012-01-01

    Three samples of 250ml at home temperature of 20°C were obtained from whole, low fat and fat free bovine UHT milk. They were analysed by measuring both impedance spectra and dc conductivity in order to establish the relationship between samples related to fat content. An impedance measuring system was developed, which is based on digital oscilloscope, a current source and a FPGA. Data was measured by the oscilloscope in the frequency 1 kHz to 100 kHz. It was showed that there is approximately 7.9% difference in the conductivity between whole and low fat milk whereas 15.9% between low fat and free fat one. The change of fatness in the milk can be significantly sensed by both impedance spectra measurements and dc conductivity. This result might be useful for detecting fat content of milk in a very simple way and also may help the development of sensors for measuring milk quality, as for example the detection of mastitis.

  19. Bioelectrical impedance analysis of bovine milk fat

    Science.gov (United States)

    Veiga, E. A.; Bertemes-Filho, P.

    2012-12-01

    Three samples of 250ml at home temperature of 20°C were obtained from whole, low fat and fat free bovine UHT milk. They were analysed by measuring both impedance spectra and dc conductivity in order to establish the relationship between samples related to fat content. An impedance measuring system was developed, which is based on digital oscilloscope, a current source and a FPGA. Data was measured by the oscilloscope in the frequency 1 kHz to 100 kHz. It was showed that there is approximately 7.9% difference in the conductivity between whole and low fat milk whereas 15.9% between low fat and free fat one. The change of fatness in the milk can be significantly sensed by both impedance spectra measurements and dc conductivity. This result might be useful for detecting fat content of milk in a very simple way and also may help the development of sensors for measuring milk quality, as for example the detection of mastitis.

  20. Is bioelectrical impedance accurate for use in large epidemiological studies?

    Directory of Open Access Journals (Sweden)

    Merchant Anwar T

    2008-09-01

    Full Text Available Abstract Percentage of body fat is strongly associated with the risk of several chronic diseases but its accurate measurement is difficult. Bioelectrical impedance analysis (BIA is a relatively simple, quick and non-invasive technique, to measure body composition. It measures body fat accurately in controlled clinical conditions but its performance in the field is inconsistent. In large epidemiologic studies simpler surrogate techniques such as body mass index (BMI, waist circumference, and waist-hip ratio are frequently used instead of BIA to measure body fatness. We reviewed the rationale, theory, and technique of recently developed systems such as foot (or hand-to-foot BIA measurement, and the elements that could influence its results in large epidemiologic studies. BIA results are influenced by factors such as the environment, ethnicity, phase of menstrual cycle, and underlying medical conditions. We concluded that BIA measurements validated for specific ethnic groups, populations and conditions can accurately measure body fat in those populations, but not others and suggest that for large epdiemiological studies with diverse populations BIA may not be the appropriate choice for body composition measurement unless specific calibration equations are developed for different groups participating in the study.

  1. Is bioelectrical impedance accurate for use in large epidemiological studies?

    Science.gov (United States)

    Dehghan, Mahshid; Merchant, Anwar T

    2008-01-01

    Percentage of body fat is strongly associated with the risk of several chronic diseases but its accurate measurement is difficult. Bioelectrical impedance analysis (BIA) is a relatively simple, quick and non-invasive technique, to measure body composition. It measures body fat accurately in controlled clinical conditions but its performance in the field is inconsistent. In large epidemiologic studies simpler surrogate techniques such as body mass index (BMI), waist circumference, and waist-hip ratio are frequently used instead of BIA to measure body fatness. We reviewed the rationale, theory, and technique of recently developed systems such as foot (or hand)-to-foot BIA measurement, and the elements that could influence its results in large epidemiologic studies. BIA results are influenced by factors such as the environment, ethnicity, phase of menstrual cycle, and underlying medical conditions. We concluded that BIA measurements validated for specific ethnic groups, populations and conditions can accurately measure body fat in those populations, but not others and suggest that for large epdiemiological studies with diverse populations BIA may not be the appropriate choice for body composition measurement unless specific calibration equations are developed for different groups participating in the study. PMID:18778488

  2. The bioelectrical impedance vector migration in healthy infants.

    Science.gov (United States)

    L'Abée, Carianne; Poorts-Borger, Petra H; Gorter, Erna H G M; Piccoli, Antonio; Stolk, Ronald P; Sauer, Pieter J J

    2010-04-01

    Detecting young children with high amount of body fat is important to intervene in the development of obesity. The aim of this study is to gain inside in the bioelectrical impedance vector analysis in healthy infants. Repeated measurements of whole body reactance and resistance were assessed, using a 50kHz frequency bioelectrical impedance analysis, in 51 boys and 62 girls during infancy. Bivariate vector analysis, which can be used to determine tissue hydration and soft tissue mass, was conducted. The 95% confidence intervals of the mean vectors for different age groups and the 95%, 75% and 50% tolerance intervals were plotted, using resistance and reactance components standardized by the participant's height. During infancy impedance vectors changed significantly: A vector migration of the Xc/H of 8.50ohm/m and the R/H of -95.68ohm/m between the age of two months and eight to twelve months (p=0.0001) was observed. Bivariate, reference tolerance intervals of the impedance vectors for healthy infants at the age of two months are presented. Our results show a significant impedance vector migration during the first year of life. New reference tolerance intervals for the second month of life were constructed. Copyright 2009 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.

  3. Bioelectrical impedance analysis as a laboratory activity: At the interface of physics and the body

    Science.gov (United States)

    Mylott, Elliot; Kutschera, Ellynne; Widenhorn, Ralf

    2014-05-01

    We present a novel laboratory activity on RC circuits aimed at introductory physics students in life-science majors. The activity teaches principles of RC circuits by connecting ac-circuit concepts to bioelectrical impedance analysis (BIA) using a custom-designed educational BIA device. The activity shows how a BIA device works and how current, voltage, and impedance measurements relate to bioelectrical characteristics of the human body. From this, useful observations can be made including body water, fat-free mass, and body fat percentage. The laboratory is engaging to pre-health and life-science students, as well as engineering students who are given the opportunity to observe electrical components and construction of a commonly used biomedical device. Electrical concepts investigated include alternating current, electrical potential, resistance, capacitance, impedance, frequency, phase shift, device design, and the use of such topics in biomedical analysis.

  4. Effect of Intravenous Infusion Solutions on Bioelectrical Impedance Spectroscopy.

    Science.gov (United States)

    Yap, Jason; Rafii, Mahroukh; Azcue, Maria; Pencharz, Paul

    2017-05-01

    Bioelectrical impedance (BIA) is often used to measure body fluid spaces and thereby body composition. However, in acute animal studies, we found that impedance was driven by the saline content of intravenous (IV) fluids and not by the volume. The aim of the study was to investigate the effect of 3 different fluids acutely administered on the change in impedance, specifically resistance (R). Nine healthy adults participated in 3 treatment (0.9% saline, 5% dextrose, and a mixture of 0.3% saline + 3.3% dextrose) experiments on nonconsecutive days. They all received 1 L of one of the treatments intravenously over a 1-hour period. Repeated BIA measurements were performed prior to IV infusion and then every 5 minutes for the 1-hour infusion period, plus 3 more measurements up to 15 minutes after the completion of the infusion. The change in R in the 0.9% saline infusion experiment was significantly lower than that of the glucose and mixture treatment ( P Bioelectrical impedance spectroscopy and BIA measure salt rather than the volume changes over the infusion period. Hence, in patients receiving IV fluids, BIA of any kind (single frequency or multifrequency) cannot be used to measure body fluid spaces or body composition.

  5. Muscle development in healthy children evaluated by bioelectrical impedance analysis.

    Science.gov (United States)

    Uchiyama, Tomoka; Nakayama, Takahiro; Kuru, Satoshi

    2017-02-01

    This study aimed to use bioelectrical impedance analysis (BIA) to generate a new muscle density index (MDI), the MDI_BIA, to evaluate muscle development, and to demonstrate the changes that occur in the BIA-based muscle cross-sectional area index (MCAI_BIA) that accompany growth. We also sought to determine the traceability of chronological changes in the MDI_BIA and MCAI_BIA. Healthy children (n=112) aged 8.68±3.16years (0.33-14.00years) underwent bioelectrical impedance (BI) measurements of their upper arms, thighs, and lower legs. The MDI_BIA and MCAI_BIA were calculated, and cross-sectional investigations were conducted into the changes in these indices that accompanied growth. Data collected after 1.10±0.08years from 45 participants determined the traceability of the chronological changes in the MDI_BIA and MCAI_BIA. The MDI_BIA and MCAI_BIA were significantly positively correlated with age and height at all locations (Pchildren, and they showed significant chronological increases. Hence, these indices could be used to represent muscle development and muscle mass increases. BIA is non-invasive, convenient, and economical and it may be useful in evaluating muscle development and muscle cross-sectional areas in children. Copyright © 2016 The Japanese Society of Child Neurology. Published by Elsevier B.V. All rights reserved.

  6. Pelvic bioelectrical impedance measurements to detect rectal filling.

    Science.gov (United States)

    Ratani, R S; Yazaki, E; Maw, A; Pilot, M A; Rogers, J; Williams, N S

    1998-11-01

    Anorectal sensory deficits are an important cause of defecatory disorders and are also a reason for evacuatory difficulties in patients undergoing total anorectal reconstruction. A method to detect rectal filling would be beneficial in such patients. We have investigated the feasibility of detecting rectal filling in vitro and in vivo by measuring changes in pelvic impedance. In vitro, a model of the pelvis was constructed using a cylindrical plastic tank filled with an electrolyte solution (conductivity 3 mS cm(-1)). Conductive Visking tubing representing the rectum was suspended in the tank and incrementally filled with artificial faeces. An impedance meter detected changes in voltage on rectal filling when an alternating current of 2 mA was passed at eight frequencies (4.8 to 612 kHz). In vivo, changes in pelvic bioelectrical impedance upon retrograde and antegrade rectal filling with artificial faeces were evaluated in three pigs, four electrodes being implanted in the pelvis. Impedance measurements accurately detected 'rectal' volume changes in vitro (n = 10, p < 0.0001; Kruskal Wallis), but not in vivo (n = 68, p = 0.48; Kruskal Wallis). This was probably due to extreme sensitivity of the detecting device to movement, a problem that needs to be resolved before this technique could be used in man.

  7. The Influence of Segmental Impedance Analysis in Predicting Validity of Consumer Grade Bioelectrical Impedance Analysis Devices

    Science.gov (United States)

    Sharp, Andy; Heath, Jennifer; Peterson, Janet

    2008-05-01

    Consumer grade bioelectric impedance analysis (BIA) instruments measure the body's impedance at 50 kHz, and yield a quick estimate of percent body fat. The frequency dependence of the impedance gives more information about the current pathway and the response of different tissues. This study explores the impedance response of human tissue at a range of frequencies from 0.2 - 102 kHz using a four probe method and probe locations standard for segmental BIA research of the arm. The data at 50 kHz, for a 21 year old healthy Caucasian male (resistance of 180φ±10 and reactance of 33φ±2) is in agreement with previously reported values [1]. The frequency dependence is not consistent with simple circuit models commonly used in evaluating BIA data, and repeatability of measurements is problematic. This research will contribute to a better understanding of the inherent difficulties in estimating body fat using consumer grade BIA devices. [1] Chumlea, William C., Richard N. Baumgartner, and Alex F. Roche. ``Specific resistivity used to estimate fat-free mass from segmental body measures of bioelectrical impedance.'' Am J Clin Nutr 48 (1998): 7-15.

  8. Estimation of total body water by bioelectrical impedance analysis

    Energy Technology Data Exchange (ETDEWEB)

    Kushner, R.F.; Schoeller, D.A.

    1986-09-01

    Total body water (TBW) measured by bioelectrical impedance analysis (BIA) was directly compared with deuterium-isotope dilution in a total of 58 subjects. First, sex-specific and group equations were developed by multiple regression analysis in (10 each) obese and nonobese men and women. Height/resistive impedance was the most significant variable used to predict deuterium-dilution space (D2O-TBW) and, combined with weight, yielded R = 0.99 and SE of estimate = 1.75 L. Equations predicted D2O-TBW equally well for obese and nonobese subjects. Second, the equations were prospectively tested in a heterogeneous group of 6 males and 12 females. Sex-specific equations predicted D2O-TBW with good correlation coefficients (0.96 and 0.93), total error (2.34 and 2.89 L), and a small difference between mean predicted and measured D2O-TBW (-1.4 +/- 2.05 and -0.48 +/- 2.83 L). BIA predicts D2O-TBW more accurately than weight, height, and/or age. A larger population is required to validate the applicability of our equations.

  9. Bioelectrical impedance and indicators of body fat and cardiovascular risk in adolescents

    Directory of Open Access Journals (Sweden)

    Ismael Forte Freitas Júnior

    2008-02-01

    Full Text Available http://dx.doi.org/10.5007/1980-0037.2008v10n1p19 The purpose of this study was to analyze the relationship between bioelectric impedance and adiposity and elevated cardiovascular risk indicators, and its effectiveness for detecting appropriate nutritional status, according to the Body Mass Index. A Cross-sectional study. The sample included 900 subjects, both males and females, with ages ranging from 11 to 17 years. Nutritional status was determined according to both Body Mass Index and relative body fat, estimated by bioelectric impedance. For both sexes, bioelectric impedance was signifi cantly correlated (p< 0.05 with all adiposity and cardiovascular risk indicators. Furthermore, it exhibited high specifi city for indicating nutritional status. It can be concluded that bioelectric impedance is a useful tool for body composition assessment. It can also be concluded that in young populations, care musty be taken when choosing equations to estimate relative body fat.

  10. Feasibility of bioelectrical impedance analysis in persons with severe intellectual and visual disabilities

    NARCIS (Netherlands)

    Havinga-Top, A. M.; Waninge, A.; van der Schans, C. P.; Jager-Wittenaar, H.

    2015-01-01

    Background: Body composition measurements provide important information about physical fitness and nutritional status. People with severe intellectual and visual disabilities (SIVD) have an increased risk for altered body composition. Bioelectrical impedance analysis (BIA) has been evidenced as a

  11. The use of bioelectrical impedance to detect excess visceral and subcutaneous fat.

    Science.gov (United States)

    Fernandes, Rômulo A; Rosa, Clara S C; Buonani, Camila; Oliveira, Arli R de; Freitas Júnior, Ismael F

    2007-01-01

    To analyze bioelectrical impedance performance in detecting the presence of excess visceral fat and overweight/obesity in young Brazilians and how its values are related with them. Study sample consisted of 811 adolescents of both genders (11 to 17 years of age). Nutritional status was determined based on triceps skinfold thickness (TSF), relative body fat (bioelectrical impedance), and excess visceral fat as determined by waist circumference. Statistical analysis was performed using means, standard deviations, linear correlation, Student's t test, and ROC curve. Bioelectrical impedance achieved good performance in identifying excess visceral fat associated with overweight/obesity in both genders, and was found to be more specific (male 92.4% and female 93.8%) than sensitive (male 86.1% and female 71.8%). Our findings support the use of bioelectrical impedance to identify the presence of excess visceral and subcutaneous fat in adolescents.

  12. Bioelectrical impedance analysis: A new tool for assessing fish condition

    Science.gov (United States)

    Hartman, Kyle J.; Margraf, F. Joseph; Hafs, Andrew W.; Cox, M. Keith

    2015-01-01

    Bioelectrical impedance analysis (BIA) is commonly used in human health and nutrition fields but has only recently been considered as a potential tool for assessing fish condition. Once BIA is calibrated, it estimates fat/moisture levels and energy content without the need to kill fish. Despite the promise held by BIA, published studies have been divided on whether BIA can provide accurate estimates of body composition in fish. In cases where BIA was not successful, the models lacked the range of fat levels or sample sizes we determined were needed for model success (range of dry fat levels of 29%, n = 60, yielding an R2 of 0.8). Reduced range of fat levels requires an increased sample size to achieve that benchmark; therefore, standardization of methods is needed. Here we discuss standardized methods based on a decade of research, identify sources of error, discuss where BIA is headed, and suggest areas for future research.

  13. Specific bioelectrical impedance vector reference values for assessing body composition in the Italian elderly.

    Science.gov (United States)

    Saragat, Bruno; Buffa, Roberto; Mereu, Elena; De Rui, Marina; Coin, Alessandra; Sergi, Giuseppe; Marini, Elisabetta

    2014-02-01

    To obtain specific bioelectrical impedance vector reference values for the healthy elderly Italian population, and to study age- and sex-related differences in body composition. The study group consisted of 560 healthy individuals (265 men and 295 women) aged 65 to 100 y, whose anthropometric (height, weight, and calf, arm and waist circumferences) and bioelectrical measurements (resistance [R] and reactance [Xc], at 50 kHz and 800 μA) were recorded. R (Ω) and Xc (Ω) values were standardized for stature (H, m) to obtain the classic bioelectrical values. Specific values (resistivity [Rsp] and reactivity [Xcsp], Ω·cm) were obtained by multiplying R and Xc by a correction factor (A/L) that includes an estimate of the cross-sectional area of the body (A=0.45 arm area+0.10 waist area+0.45 calf area), where L=1.1H. Descriptive statistics were: Rsp (391.8±57.9), Xcsp (42.6±9.9), Zsp (394.2±58.2), phase angle (6.2°±1.2) in men; Rsp (462.0±80.1), Xcsp (47.9±11.2), Zsp (464.6±80.5), phase angle (5.9°±1.0) in women. The Xcsp and phase angle values showed a significant age-related decrease in both sexes, but especially in men, possibly relating to a gradual loss of muscle mass. Women's Rsp and Zsp values tended to drop, attributable to their declining proportion of fat mass. A declining sexual dimorphism was also apparent. Specific tolerance ellipses can be used for reference purposes for the Italian population when assessing body composition in gerontological practice and for epidemiological purposes. Copyright © 2013 Elsevier Inc. All rights reserved.

  14. Effects of resistance training on classic and specific bioelectrical impedance vector analysis in elderly women.

    Science.gov (United States)

    Fukuda, David H; Stout, Jeffrey R; Moon, Jordan R; Smith-Ryan, Abbie E; Kendall, Kristina L; Hoffman, Jay R

    2016-02-01

    Raw bioelectrical impedance analysis (BIA) data [resistance (R); reactance (Xc)] through bioelectrical impedance vector analysis (BIVA) and phase angle (PhA) have been used to evaluate cellular function and hydration status. The purpose of this investigation was to examine the effects of resistance training (RT) on classic and specific BIVA in elderly women. Twenty women (mean ± SD; age: 71.9 ± 6.9 years; BMI: 24.5 ± 3.0 kg m(-2)) completed a 6-month RT program. Whole-body, single-frequency BIA, body geometry, and leg strength (5RM) measures were completed at baseline (t0), 3 months (t3), and 6 months (t6). The mean impedance vector displacements were compared using Hotelling's T(2) test to evaluate changes in R and Xc relative to height (R/ht; Xc/ht) or body volume (Rsp; Xcsp) estimated from the arms, legs, and trunk. 5RM, PhA, and BIVA variables were compared using ANOVA. PhA improved at t6 (p < 0.01), while 5RM improved at t3 and t6 (p < 0.01). Using classic BIVA, 6 months (T(2) = 31.6; p < 0.01), but not 3 months of RT (T(2) = 4.5; p = 0.20), resulted in significant vector migration. Using specific BIVA, 6 months (T(2) = 24.4; p < 0.01), but not 3 months of RT (T(2) = 5.5; p = 0.10), also resulted in significant vector migration. 5RM was correlated to both PhA (r = 0.48-56) and Xcsp (r = 0.45-53) at all time points. Vector displacements were likely the result of improved cellular integrity (Xcsp) and cellular health (PhA). Copyright © 2015 Elsevier Inc. All rights reserved.

  15. Smart Multi-frequency Bioelectrical Impedance Spectrometer for BIA and BIVA Applications

    Science.gov (United States)

    Harder, Rene; Diedrich, André; Whitfield, Jonathan; Buchowski, Maciej S.; Pietsch, John B.; Baudenbacher, Franz

    2016-01-01

    Bioelectrical impedance analysis (BIA) is a noninvasive and commonly used method for the assessment of body composition including body water. We designed a small, portable and wireless multi-frequency impedance spectrometer based on the 12 bit impedance network analyzer AD5933 and a precision wide-band constant current source for tetrapolar whole body impedance measurements. The impedance spectrometer communicates via Bluetooth with mobile devices (smart phone or tablet computer) that provide user interface for patient management and data visualization. The export of patient measurement results into a clinical research database facilitates the aggregation of bioelectrical impedance analysis and biolectrical impedance vector analysis (BIVA) data across multiple subjects and/or studies. The performance of the spectrometer was evaluated using a passive tissue equivalent circuit model as well as a comparison of body composition changes assessed with bioelectrical impedance and dual-energy X-ray absorptiometry (DXA) in healthy volunteers. Our results show an absolute error of 1% for resistance and 5% for reactance measurements in the frequency range of 3kHz to 150kHz. A linear regression of BIA and DXA fat mass estimations showed a strong correlation (r2=0.985) between measures with a maximum absolute error of 6.5%. The simplicity of BIA measurements, a cost effective design and the simple visual representation of impedance data enables patients to compare and determine body composition during the time course of a specific treatment plan in a clinical or home environment. PMID:26863670

  16. Development of high time resolution measurement system of frequency characteristics in bioelectrical impedance for biodynamic analysis

    Science.gov (United States)

    Nakamura, Takao; Kusuhara, Toshimasa; Yamamoto, Yoshitake

    2006-11-01

    We have proposed biodynamic analysis using bioelectrical impedance at 50 kHz, which is measured with synchronous rectification method. In order to analyze impedance parameters in biodynamics, the measurement of frequency characteristics in bioelectrical impedance with a high time resolution are required. Therefore we have developed a high time resolution measurement system for bioelectrical impedance with 10 frequency points and time resolution of 1 ms. A voltage E A, which consisted of fundamental wave and 9 kinds of harmonic wave from 1 kHz to 1MHz, were converted to current. The current flowed through human body and a potential voltage, EV was detected in the measured part. After A/D conversion of EV and E A in the sampling frequency 2 MHz, data number 2048 points, the impedance were calculated using Fast Fourier Transform. The measured time 1.024 ms was the period of the fundamental wave and time resolution of this system. The specification is enough accuracy for measurement of bioelectrical impedance for biodynamic analysis.

  17. Hydration assessment among marathoners using urine specific gravity and bioelectrical impedance analysis.

    Science.gov (United States)

    Cutrufello, Paul T; Dixon, Curt B; Zavorsky, Gerald S

    2016-01-01

    The present study examined the relationship between urine specific gravity (Usg), body mass (BM) and bioelectrical impedance determined variables [total body water (TBW), per cent TBW and impedance values] before and after a marathon (n = 25 men; 10 women). A significant reduction in BM (pre: 71.2 ± 12.4 kg; post: 69.6 ± 12.0 kg; p Impedance values were significantly greater post-race (pre: 3288 ± 482; post: 3416 ± 492 Ω; p bioelectrical impedance determined variables. On average, BM, Usg and impedance values appear to express changes in hydration; however, the observed changes among these variables for a given individual appear to be inconsistent with one another.

  18. Bioelectrical impedance analysis and age-related differences of body composition in the elderly.

    Science.gov (United States)

    Guida, Bruna; Laccetti, Roberta; Gerardi, Clara; Trio, Rossella; Perrino, Nunzia Ruggiero; Strazzullo, Pasquale; Siani, Alfonso; Farinaro, Eduardo; Colantuoni, Antonio

    2007-03-01

    Significant changes in body composition that have important health related effects may occur in the elderly. In this study, we evaluated the bioelectrical characteristics in a large group of apparently healthy Caucasian men in the age range 50-80 years, as a function of age and body mass index. We studied 315 men with ages ranging from 50 to 80 years. They were divided into three groups according to body mass index (kg/m(2)): 18.5-24.9 normoweight (NW); 25.0-29.9 overweight (OW); > or =30 obese (OB), and they were classified in nine age subgroups: 50-59 (young-old, YO); 60-69 (old, O); 70-80 (oldest, OS). Fat-free mass, fat mass and body cell mass were investigated using conventional bioelectrical impedance analysis. Body composition was also assessed by bioelectrical impedance vector analysis and the RXc graph method. Body cell mass decreased significantly with age particularly in subgroups of the OW and OB groups (pbioelectrical impedance analysis indicating decreased soft tissue mass (fat-free mass and body cell mass), particularly in OW and OB-OS healthy men. We suggest 70 years of age as a cut-off for significant quantitative and qualitative (tissue electrical properties) body composition modifications. This bioelectrical impedance vector analysis pattern associated with ageing and across the different body mass index categories, may be useful for clinical purposes and can be used in geriatric routine to accurately assess the body composition modifications occurring in the elderly.

  19. Body fat assessment by bioelectrical impedance and its correlation with anthropometric indicators.

    Science.gov (United States)

    Diniz Araújo, Ma L; Coelho Cabral, P; Kruze Grande de Arruda, I; Siqueira Tavares Falcão, A P; Silva Diniz, A

    2012-01-01

    Since the excess of body fat is associated with higher morbid-mortality rates (mainly in adults), precise, reliable, cost-effective, and broadly applicable methods are necessary for its assessment in population-based studies and in clinical practice. To evaluate the correlation between body fat estimated either by bioelectrical impedance or by the sum of skinfold thicknesses and anthropometric indicators of fat distribution. A cross-sectional study was conducted enrolled 348 undergraduate students (median 21 years), from the Federal University of Pernambuco, Northeast Brazil. 262 of the subjects were women. Mean body fat assessed by bioelectrical impedance was 22.3 ± 6.2% in women and 15.2 ± 4.2% in men. Body fat obtained by the sum of skinfold thicknesses was similar to that assessed by bioelectrical impedance only in men. A strong correlation was observed between body fat assessed by bioelectrical impedance and that assessed by the sum of the skinfold thicknesses, waist circumference and waist-to-height ratio. Regarding the conicity index, there was a moderate correlation for men and a weak correlation for women. The sum of skinfold thicknesses surrogate of body fat percentage and can be used to assess body fat when BIA is not available in the field. Additional information about central fat distribution can be supply by measuring the waist circumference or waist-to-height ratio.

  20. Impact of hemodialysis on dual X-ray absorptiometry, bioelectrical impedance measurements, and anthropometry

    DEFF Research Database (Denmark)

    Abrahamsen, Bo; Hansen, T B; Høgsberg, I M

    1996-01-01

    ), bioelectrical impedance analysis (BIA), and simple anthropometry in 19 patients (9 women and 10 men, mean age 46 y) before and after hemodialysis, removing 0.9-4.3 L (x: 2.8L) of ultrafiltrate. The reduction in fat-free mass (FFM) measured by DXA was highly correlated with the ultrafiltrate, as determined...

  1. Bioelectrical impedance analysis to define an excess of body fat: evaluation in patients with psoriasis.

    Science.gov (United States)

    Galluzzo, M; Talamonti, M; Perino, F; Servoli, S; Giordano, D; Chimenti, S; De Simone, C; Peris, K

    2017-06-01

    There is strong evidence that obesity is closely associated with psoriasis. However, data on body composition are lacking in psoriasis. The purpose of this study were to investigate the body composition in psoriasis patients using bioelectrical impedance analysis and to correlate the bioelectrical impedance data with disease severity and laboratory parameters. Anthropometric measurements and bioelectrical impedance analyses were performed on patients with psoriasis, naïve to any systemic treatment, who attended the outpatient clinics of two University centers. Data of 164 adult patients were analyzed. Compared to men, women had several significantly higher bioelectrical impedance parameters including reactance, fat mass% and adipose tissue%. The values of adipose tissue were positively correlated only with patients age (p = .021) and age at disease onset (p = .0006), but not with disease severity. In addition, we observed that the use of BMI cutoffs allowed to categorize 36.7% of women and 19.2% of men as obese, while fat mass% showed that 53.3% of women and 48.1% of men were obese. In our study, psoriasis is been associated with a high fat mass%. We suggest that screening for body fat distribution in psoriatic patients might be useful to identify early obesity-related disease.

  2. The use of bioelectrical impedance analysis for body composition in epidemiological studies

    DEFF Research Database (Denmark)

    Böhm, A; Heitmann, B L

    2013-01-01

    BACKGROUND/OBJECTIVES: Bioelectrical impedance analysis (BIA) is a relatively simple, inexpensive and non-invasive technique to measure body composition and is therefore suitable in field studies and larger surveys. SUBJECTS/METHODS: We performed an overview of BIA-derived body fat percentages (B...

  3. Smartphone-Based Bioelectrical Impedance Analysis Devices for Daily Obesity Management

    OpenAIRE

    Choi, Ahyoung; Kim, Justin Younghyun; Jo, Seongwook; Jee, Jae Hwan; Heymsfield, Steven B.; Bhagat, Yusuf A.; Kim, Insoo; Cho, Jaegeol

    2015-01-01

    Current bioelectric impedance analysis (BIA) systems are often large, cumbersome devices which require strict electrode placement on the user, thus inhibiting mobile capabilities. In this work, we developed a handheld BIA device that measures impedance from multiple frequencies (5 kHz~200 kHz) with four contact electrodes and evaluated the BIA device against standard body composition analysis systems: a dual-energy X-ray absorptiometry (DXA) system (GE Lunar Prodigy, GE Healthcare, Buckingha...

  4. [Body composition assessment by anthropometry and bioelectrical impedance].

    Science.gov (United States)

    Aristizábal, Juan Carlos; Restrepo, María Teresa; Estrada, Alejandro

    2007-06-01

    Anthropometry and electric impedance methods are widely used for body composition assessment. However the evidence is unclear whether the results obtained from the two methods can be compared. Two methods are compared for assessment of body composition; anthropometry and electric impedance. Body composition was measured in 70 women; aged 22 to 56 and 53 men; aged 24 to 54, using anthropometry (Durning/Womersley and Jackson/Pollock skinfolds equations) and electric impedance (foot to foot electric impedance) to obtain percentage body fat. The mean percentage body fat was significant higher with Durning/Womersley (25.2%) than Jackson/Pollock (20.1%) and electric impedance (19.3%) for men (pimpedance (27.6%) for women (p0.77) however, the concordance between methods to classify obesity subjects was low (Kbioelectrical impedance method. A significant difference was found between methods applied in men and women, and therefore these methods are not comparable.

  5. Prevalence of child malnutrition at a university hospital using the World Health Organization criteria and bioelectrical impedance data.

    Science.gov (United States)

    Pileggi, V N; Monteiro, J P; Margutti, A V B; Camelo, J S

    2016-03-01

    Malnutrition constitutes a major public health concern worldwide and serves as an indicator of hospitalized patients' prognosis. Although various methods with which to conduct nutritional assessments exist, large hospitals seldom employ them to diagnose malnutrition. The aim of this study was to understand the prevalence of child malnutrition at the University Hospital of the Ribeirão Preto Medical School, University of São, Brazil. A cross-sectional descriptive study was conducted to compare the nutritional status of 292 hospitalized children with that of a healthy control group (n=234). Information regarding patients' weight, height, and bioelectrical impedance (i.e., bioelectrical impedance vector analysis) was obtained, and the phase angle was calculated. Using the World Health Organization (WHO) criteria, 35.27% of the patients presented with malnutrition; specifically, 16.10% had undernutrition and 19.17% were overweight. Classification according to the bioelectrical impedance results of nutritional status was more sensitive than the WHO criteria: of the 55.45% of patients with malnutrition, 51.25% exhibited undernutrition and 4.20% were overweight. After applying the WHO criteria in the unpaired control group (n=234), we observed that 100.00% of the subjects were eutrophic; however, 23.34% of the controls were malnourished according to impedance analysis. The phase angle was significantly lower in the hospitalized group than in the control group (P<0.05). Therefore, this study suggests that a protocol to obtain patients' weight and height must be followed, and bioimpedance data must be examined upon hospital admission of all children.

  6. Bioelectrics

    CERN Document Server

    Heller, Richard

    2017-01-01

    This book focuses on bioelectrics, a new multidisciplinary field encompassing engineering and biology with applications to the medical, environmental, food, energy, and biotechnological fields. At present, 15 universities and institutes in Japan, the USA and the EU comprise the International Consortium of Bioelectrics, intended to advance this novel and important research field. This book will serve as an introductory resource for young scientists and also as a textbook for use by both undergraduate and graduate students – the world’s first such work solely devoted to bioelectrics.

  7. New specific bioelectrical impedance vector reference values for assessing body composition in the Italian-Spanish young adult population.

    Science.gov (United States)

    Ibáñez, Maria E; Mereu, Elena; Buffa, Roberto; Gualdi-Russo, Emanuela; Zaccagni, Luciana; Cossu, Stefano; Rebato, Esther; Marini, Elisabetta

    2015-01-01

    Specific bioelectrical impedance vector analysis (spBIVA) is a recently proposed technique for the analysis of body composition. The aim of this study was to apply spBIVA to a sample of Italian and Spanish young adults and to define the new bioelectrical references for this Western Mediterranean population. A sample of 440 individuals (220 from Italy, 220 from Spain; 213 men, 227 women) aged 18-30 years was considered. Anthropometric (height, weight, relaxed upper arm, waist, and calf girths) and bioelectrical (resistance, reactance; 50 kHz, 800 μA) measurements were taken. In order to verify the need for new references, specific bioelectrical values were compared to the reference values for U.S. adults and Italian elderly by tolerance ellipses and Student's t test. The mean specific bioelectrical values (resistivity, Rsp, and reactivity, Xcsp, Ohm·cm) were: Rsp (332.7 ± 41.7 Ω·cm), Xcsp (44.4 ± 6.8 Ω·cm), Zsp (335.6 ± 41.9 Ω·cm) and phase (7.6 ± 0.8°) in men; Rsp (388.6 ± 60 Ω·cm), Xcsp (43.7 ± 7.5 Ω·cm), Zsp (391.0 ± 60.3 Ω·cm) and phase (6.4 ± 0.7°) in women. Italo-Spanish bioelectrical vectors were mainly distributed (>90%) in the lower part of the tolerance ellipses for U.S. young adults, due to a shorter impedance (P 90%), due to a higher phase (P < 0.001), indicative of higher body cell mass. These population and age-related differences indicate the need for new specific tolerance ellipses that can be used as references for assessing body composition in young adults from Western Mediterranean populations. © 2015 Wiley Periodicals, Inc.

  8. Bioelectrical impedance spectroscopy for the assessment of body fluid volumes of term neonates

    Directory of Open Access Journals (Sweden)

    Ferreira D.M.

    2004-01-01

    Full Text Available The assessment of fluid volume in neonates by a noninvasive, inexpensive, and fast method can contribute significantly to increase the quality of neonatal care. The objective of the present study was to calibrate an acquisition system and software to estimate the bioelectrical impedance parameters obtained by a method of bioelectrical impedance spectroscopy based on step response and to develop specific equations for the neonatal population to determine body fluid compartments. Bioelectric impedance measurements were performed by a laboratory homemade instrument. The volumes were estimated in a clinical study on 30 full-term neonates at four different times during the first month of life. During the first 24 hours of life the total body water, extracellular water and intracellular water were 2.09 ± 0.25, 1.20 ± 0.19, and 0.90 ± 0.25 liters, respectively. By the 48th hour they were 1.87 ± 0.27, 1.08 ± 0.17, and 0.79 ± 0.21 liters, respectively. On the 10th day they were 2.02 ± 0.25, 1.29 ± 0.21, and 0.72 ± 0.14 liters, respectively, and after 1 month they were 2.34 ± 0.27, 1.62 ± 0.20, and 0.72 ± 0.13 liters, respectively. The behavior of the estimated volume was correlated with neonatal body weight changes, leading to a better interpretation of such changes. In conclusion, this study indicates the feasibility of bioelectrical impedance spectroscopy as a method to help fluid administration in intensive care neonatal units, and also contribute to the development of new equations to estimate neonatal body fluid contents.

  9. The potential of classic and specific bioelectrical impedance vector analysis for the assessment of sarcopenia and sarcopenic obesity

    Directory of Open Access Journals (Sweden)

    Marini E

    2012-12-01

    Full Text Available Elisabetta Marini,1 Roberto Buffa,1 Bruno Saragat,1 Alessandra Coin,2 Elena Debora Toffanello,2 Linda Berton,2 Enzo Manzato,2 Giuseppe Sergi21Department of Environmental and Life Sciences, University of Cagliari, Italy; 2Department of Medicine-DIMED, Geriatrics Section, University of Padua, ItalyPurpose: The aim of this paper is to investigate whether bioelectrical impedance vector analysis (BIVA can be a suitable technique for the assessment of sarcopenia. We also investigate the potential use of specific BIVA as an indicator of sarcopenic obesity.Subjects and methods: The sample comprised 207 free-living elderly individuals of both sexes, aged 65 to 93 years. Anthropometric and bioelectrical measurements were taken according to standard criteria. The “classic” and “specific” BIVA procedures, which respectively correct bioelectrical values for body height and body geometry, were used. Dual energy X-ray absorptiometry (DXA was used as the reference method for identifying sarcopenic and obese sarcopenic individuals. Bioelectrical and DXA values were compared using Student’s t-test and Hotelling’s T2 test, as well as Pearson’s correlation coefficient.Results: According to classic BIVA, sarcopenic individuals of both sexes showed higher values of resistance/height (R/H; p < 0.01 and impedance/height (Z/H; p < 0.01, and a lower phase angle (p < 0.01. Similarly, specific BIVA showed significant differences between sarcopenic and nonsarcopenic individuals (men: T2 = 15.7, p < 0.01; women: T2 = 10.7, p < 0.01, with the sarcopenic groups showing a lower specific reactance and phase angle. Phase angle was positively correlated with the skeletal muscle mass index (men: r = 0.52, p < 0.01; women: r = 0.31, p < 0.01. Specific BIVA also recognized bioelectrical differences between sarcopenic and sarcopenic obese men (T2 = 13.4, p < 0.01, mainly due to the higher values of specific R in sarcopenic obese individuals.Conclusion: BIVA detected

  10. Assessment of body composition in subjects with metabolic syndrome comparing single-frequency bioelectrical impedance analysis and bioelectrical spectroscopy.

    Science.gov (United States)

    Cloetens, Lieselotte; Johansson-Persson, Anna; Helgegren, Hannah; Landin-Olsson, Mona; Uusitupa, Matti; Åkesson, Björn; Önning, Gunilla

    2015-03-01

    The aim of this study was to investigate the agreement between body composition measurements made with two methods-single-frequency bioelectrical impedance analysis (SF-BIA) and bioelectrical impedance spectroscopy (BIS). The body composition measurements using SF-BIA and BIS were performed seven times during 6 months on 41 patients (13 men and 28 women) with metabolic syndrome who were taking part in a dietary intervention study. The mean [standard deviation (SD)] fat mass (FM) and median [interquartile range (IQR)] FM% measured with SF-BIA were 32.7 (6.7) kg and 36.3 (30.3-39.3)%, respectively, compared with 38.2 (8.7) kg and 40.9 (35.5-45.6)%, respectively, using BIS. The median (IQR) fat-free mass (FFM) was 60.0 (53.3-73.5) kg according to SF-BIA and 55.4 (48.8-66.5) kg according to BIS. These results obtained with the two methods were significantly different (P<0.001). Still highly significant correlations were found between the results obtained with SF-BIA and BIS for FM and FFM (all r≥0.89, P<0.001). Using Bland-Altman analysis, the bias was found to be -5.4 (4.1) kg for FM, -5.5 (3.7)% for FM%, and 5.4 (4.1) kg for FFM. Rather wide limits of agreement were found for FM, FM%, and FFM. Body composition data obtained using SF-BIA and BIS in subjects with metabolic syndrome were highly correlated but not interchangeable. FM was systematically lower when using SF-BIA than when using BIS.

  11. Bioelectrical impedance analysis for the prediction of hot carcass weight in buffalo calf

    Directory of Open Access Journals (Sweden)

    Leopoldo Iannuzzi

    2010-01-01

    Full Text Available Twenty young buffalo male calves were fed ad libitum with a total mix ration and with vitamin-mineral integration for 14 months. Seven days before slaughter, the animals were weighed and bioelectrical impedance measurements were collected in live animals. Physical and chemical characteristics were assessed on the Longissimus dorsi muscle after slaughter. Correlations and regression equations were calculated to determine the possible use of bioelectrical impedance for evaluating hot carcass weight. Bioelectrical impedance analysis at different frequencies, simple correlation and analysis of regression were examined for all the data collected, supporting the possibility of hot carcass weight prediction with equation at multifrequency. The results show that, probably due to the variability in animal live weight, the distribution of the colour parameters was not normally distributed. Moreover, using different frequencies of resistance and reactance, hot carcass weight in buffalo may be predicted with the following equation: Y=98.47–8.84(Rs100KHz+4.41(Rs1000 KHz-116.27(Xc5 KHz+51.04(Xc50 KHz+20.30(Xc100 KHz-33.92(Xc500 KHz+9.01(Xc1000 KHz±ε (Adjusted R Square value of .907 and SE of 5.728 However, further studies are required to improve the technique also in buffalo, after standardization of the method.

  12. EFFECTS OF FOOD AND DRINK INGESTION ON BODY COMPOSITION VARIABLES OF ABDOMINAL BIOELECTRICAL IMPEDANCE.

    Science.gov (United States)

    Fernández Vázquez, Rosalía; Martínez Blanco, Javier; García Vega, María del Mar; Barbancho, Miguel Ángel; Alvero-Cruz, José Ramón

    2015-11-01

    to know the changes in trunk fat and visceral fat level determined by abdominal bioelectrical impedance (BIA) as well as other anthropometric measures related to the central or abdominal fat after the ingestion of a lunch. the experimental study was conducted to assess a longitudinal intervention descriptive study. 21 subjects (10 male and 11 female), volunteers who have access to a medical assessment, with an age of 74 ± 13.43 years. Maximal waist circumference in standing position, waist circumference at navel level in supine position and sagittal abdominal diameter (SAD). In the same position trunk fat and visceral fat level by abdominal bioelectrical impedance analysis with Tanita AB-140 (ViScan) were obtained before and after meal. anthropometric measures as waist circumference in supine position and SAD did not show significant differences (P > 0.05), after food ingestion, except for a significant increase of the maximal waist circumference in standing position (P 0.05). The percentage changes of the measures were less than 2% for waist circumference in standing position, waist circumference by Viscan, sagittal abdominal diameter and trunk fat and 5.9% for visceral fat ratio. the effects on trunk fat and visceral fat ratio by abdominal bioelectrical impedance are minimal after the ingestion of a portion of food and drink, although it is always recommended to do it in fasting conditions. Copyright AULA MEDICA EDICIONES 2014. Published by AULA MEDICA. All rights reserved.

  13. Bioelectrical impedance parameters in critically ill children: importance of reactance and resistance.

    Science.gov (United States)

    Azevedo, Zina Maria Almeida; Moore, Daniella Campelo Batalha Cox; de Matos, Flavia Aparecida Alves; Fonseca, Vania Matos; Peixoto, Maria Virginia Marques; Gaspar-Elsas, Maria Ignez C; Santinoni, Erika; Dos Anjos, Luiz Antonio; Ramos, Eloane Gonçalves

    2013-10-01

    Currently, there are no clinical or laboratory parameters that can be used efficiently to predict the prognosis of critically ill patients, but in some situations, raw bioelectrical impedance parameters have been shown to be useful. The purpose of this study was to investigate the behavior of reactance and resistance in the severity of the critically ill pediatric patient. We prospectively analyzed bioelectrical impedance in a sample of 332 critically ill pediatric patients submitted to mechanical ventilation. The values taken on admission and discharge were correlated with major outcomes to the critically ill patient. We found an association of low values of Xc/H (Bioelectrical impedance is a useful tool for monitoring of critically ill pediatric patients. A possible role of R/H and Xc/H, especially the latter, as a predictive biomarker of evolution for septic shock and organ dysfunction still remains to be elucidated. Copyright © 2013 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.

  14. Nutritional assessment of amyotrophic lateral sclerosis in routine practice: value of weighing and bioelectrical impedance analysis.

    Science.gov (United States)

    Roubeau, Vincent; Blasco, Hélène; Maillot, François; Corcia, Philippe; Praline, Julien

    2015-04-01

    We evaluated clinical and bioelectrical impedance (BIA) parameters at the time of diagnosis and during follow-up and associated these parameters with survival in amyotrophic lateral sclerosis (ALS) patients. One hundred seventeen patients were enrolled and were evaluated prospectively every 3 months. All patients underwent at least 1 BIA-based assessment, and 73 underwent at least 2 assessments. Data regarding the site of onset, age at onset, weight, body mass index (BMI), amyotrophic lateral sclerosis functional rating scale score (ALSFRS), fat-free mass (FFM), fat mass (FM), and phase angle (PA) were collected. At the time of diagnosis, weight loss exceeding 5% of the premorbid weight and low PA were poor prognostic factors. During follow-up, a decrease of PA and FFM were associated with shorter survival, regardless of weight loss. These results confirm that BIA is useful to identify poor prognostic factors at the time of diagnosis and during follow-up and thus could be used to monitor patients during follow-up. Early identification of poor prognostic factors enables nutritional management and might improve patient survival. © 2014 Wiley Periodicals, Inc.

  15. Body composition of patients with autism spectrum disorder through bioelectrical impedance.

    Science.gov (United States)

    Castro, Kamila; Slongo Faccioli, Larissa; Baronio, Diego; Gottfried, Carmem; Schweigert Perry, Ingrid; Riesgo, Rudimar

    2017-07-28

    Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by deficits in sociability, communication, and limited repertoire of interests and behaviors. We aimed to investigate the nutritional status through bioelectrical impedance analysis (BIA) and antrophometrics variables in 63 ASD children and adolescents (10.5 ± 4.1 years; 81% male). Anthropometric variables were weight, height, and waist circumference (WC); body composition (fat mass, fat free mass) and phase angle (PA) were obtained through BIA. The body mass index showed a prevalence of overweight, obesity and underweight of 38.9, 36.5 and 15.8%, respectively. According to the body fat percentual, obesity prevalence was 49.2%, and 49.2% showed WC > 80th percentile for age. Eleven patients presented lower PA values than references. According to the these parameters, a large percentual of ASD children and adolescents in this sample had total overweight and obesity and truncal adiposity, which causes concern, as well as the percentage of underweight participants.

  16. [Abdomen specific bioelectrical impedance analysis (BIA) methods for evaluation of abdominal fat distribution].

    Science.gov (United States)

    Ida, Midori; Hirata, Masakazu; Hosoda, Kiminori; Nakao, Kazuwa

    2013-02-01

    Two novel bioelectrical impedance analysis (BIA) methods have been developed recently for evaluation of intra-abdominal fat accumulation. Both methods use electrodes that are placed on abdominal wall and allow evaluation of intra-abdominal fat area (IAFA) easily without radiation exposure. Of these, "abdominal BIA" method measures impedance distribution along abdominal anterior-posterior axis, and IAFA by BIA method(BIA-IAFA) is calculated from waist circumference and the voltage occurring at the flank. Dual BIA method measures impedance of trunk and body surface at the abdominal level and calculates BIA-IAFA from transverse and antero-posterior diameters of the abdomen and the impedance of trunk and abdominal surface. BIA-IAFA by these two BIA methods correlated well with IAFA measured by abdominal CT (CT-IAFA) with correlatipn coefficient of 0.88 (n = 91, p obesity.

  17. Bioelectrical impedance vector analysis (BIVA) for the assessment of two-compartment body composition.

    Science.gov (United States)

    Buffa, R; Mereu, E; Comandini, O; Ibanez, M E; Marini, E

    2014-11-01

    This review is directed to define the efficacy of bioelectrical impedance vector analysis (BIVA) for assessing two-compartment body composition. A systematic literature review using MEDLINE database up to 12 February 2014 was performed. The list of papers citing the first description of BIVA, obtained from SCOPUS, and the reference lists of included studies were also searched. Selection criteria included studies comparing the results of BIVA with those of other techniques, and studies analyzing bioelectrical vectors of obese, athletic, cachectic and lean individuals. Thirty articles met the inclusion criteria. The ability of classic BIVA for assessing two-compartment body composition has been mainly evaluated by means of indirect techniques, such as anthropometry and bioelectrical impedance analysis (BIA). Classic BIVA showed a high agreement with body mass index, that can be interpreted in relation to the greater body mass of obese and athletic individuals, whereas the comparison with BIA showed less consistent results, especially in diseased individuals. When a reference method was used, classic BIVA failed to accurately recognize FM% variations, whereas specific BIVA furnished good results. Specific BIVA is a promising alternative to classic BIVA for assessing two-compartment body composition, with potential application in nutritional, sport and geriatric medicine.

  18. Evaluation of body composition in COPD patients using multifrequency bioelectrical impedance analysis.

    Science.gov (United States)

    de Blasio, Francesca; de Blasio, Francesco; Miracco Berlingieri, Giulia; Bianco, Andrea; La Greca, Marta; Franssen, Frits M E; Scalfi, Luca

    2016-01-01

    Multifrequency bioelectrical impedance analysis (MF-BIA) is a technique that measures body impedance (Z) at different frequencies (5, 10, 50, 100, and 250 kHz). Body composition may be estimated using empirical equations, which include BIA variables or, alternatively, raw BIA data may provide direct information on water distribution and muscle quality. To compare raw MF-BIA data between COPD patients and controls and to study their relationship with respiratory and functional parameters in COPD patients. MF-BIA was performed (Human Im-Touch analyzer) in 212 COPD patients and 115 age- and BMI-matched controls. Fat-free mass (FFM) and fat mass were estimated from BIA data, and low- to high-frequency (5 kHz/250 kHz) impedance ratio was calculated. Physical fitness, lung function and respiratory muscle strength were also assessed in COPD patients. After adjusting for age, weight, and body mass index, FFM and the 5/250 impedance ratio were lower in COPD patients ( P impedance ratio was significantly correlated mainly with age ( r =-0.316 and r =-0.346, respectively). Patients with a 5/250 impedance ratio below median value had lower handgrip strength ( P impedance ratio was reduced ( P impedance ratio could give valuable information on cellular integrity and muscle quality.

  19. Sex and age specific prediction formulas for estimating body composition from bioelectrical impedance : a cross-validation study

    NARCIS (Netherlands)

    Deurenberg, P.; van der Kooy, K; Leenen, R; Weststrate, J A; Seidell, J C

    In 827 male and female subjects, with a large variation in body composition and an age range of 7-83 years, body composition was measured by densitometry, anthropometry and bioelectrical impedance. The relationship between densitometrically determined fat free mass (FFM) with body impedance (R),

  20. Assessment of adult body composition using bioelectrical impedance: comparison of researcher calculated to machine outputted values.

    Science.gov (United States)

    Franco-Villoria, Maria; Wright, Charlotte M; McColl, John H; Sherriff, Andrea; Pearce, Mark S

    2016-01-07

    To explore the usefulness of Bioelectrical Impedance Analysis (BIA) for general use by identifying best-evidenced formulae to calculate lean and fat mass, comparing these to historical gold standard data and comparing these results with machine-generated output. In addition, we explored how to best to adjust lean and fat estimates for height and how these overlapped with body mass index (BMI). Cross-sectional observational study within population representative cohort study. Urban community, North East England Sample of 506 mothers of children aged 7-8 years, mean age 36.3 years. Participants were measured at a home visit using a portable height measure and leg-to-leg BIA machine (Tanita TBF-300MA). Height, weight, bioelectrical impedance (BIA). Lean and fat mass calculated using best-evidenced published formulae as well as machine-calculated lean and fat mass data. Estimates of lean mass were similar to historical results using gold standard methods. When compared with the machine-generated values, there were wide limits of agreement for fat mass and a large relative bias for lean that varied with size. Lean and fat residuals adjusted for height differed little from indices of lean (or fat)/height(2). Of 112 women with BMI >30 kg/m(2), 100 (91%) also had high fat, but of the 16 with low BMI (Bioelectrical impedance can supply a robust and useful field measure of body composition, so long as the machine-generated output is not used. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  1. Body fluid volume and nutritional status in hemodialysis: vector bioelectric impedance analysis.

    Science.gov (United States)

    Espinosa Cuevas, M A; Navarrete Rodriguez, G; Villeda Martinez, M E; Atilano Carsi, X; Miranda Alatriste, P; Tostado Gutiérrez, T; Correa-Rotter, R

    2010-04-01

    Protein-energy malnutrition and hypervolemia are major causes of morbidity and mortality in patients on chronic hemodialysis (CHD). The methods used to evaluate nutritional status and volume status remain controversial. Vector bioelectric impedance analysis (vector- BIA) has recently been developed to assess both nutritional status and tissue hydration. The purpose of the study was to assess the nutritional status and volume status of patients on CHD with conventional nutritional assessment methods and with vector-BIA and then to compare the resulting findings. 76 Mexican patients on CHD were studied. Nutritional status and body composition were assessed with anthropometry, biochemical variables, and the modified Bilbrey nutritional index (mBNI), the results were compared with both conventional BIA and vector-BIA. The BNI was used to determine the number of patients with normal nutritional status (n = 27, 35.5%), and mild (n = 31, 40.8%), moderate (n = 10, 13.2%) and severe malnutrition (n = 8, 10.5%). Patients displayed shorter vectors with smaller phase angles or with an overhydration vectorial pattern before the initiation of their hemodialysis session. There was general improvement to normal hydration status post-dialysis (p hemodialysis session. Diabetics and those with moderate or severe malnutrition were more overhydrated, which is a condition that may be associated with increased cardiovascular morbidity. Because nutritional and volume status are important factors associated with morbidity and mortality in CHD patients, we focused on optimizing the use of existing methods. Our studies suggest that vector-BIA offers a comprehensive and reliable reproducible means of assessing both volume and masses at the bedside and can complement the traditional methods.

  2. Bioelectrical impedance vector analysis detects low body cell mass and dehydration in patients with Alzheimer's disease.

    Science.gov (United States)

    Buffa, R; Mereu, R M; Putzu, P F; Floris, G; Marini, E

    2010-12-01

    This paper evaluates the nutritional status in patients with mild-moderate and severe Alzheimer's disease (AD) by bioelectrical impedance vector analysis (BIVA). Cross-sectional study. Alzheimer Center, SS. Trinita Hospital, Cagliari, and "Monsignor Angioni" Nursing Home, Quartu Sant'Elena (Cagliari, Italy). 83 free-living patients with mild-moderate Alzheimer's disease (29 men, 54 women), 9 institutionalized women in the severe stage; 468 age-matched controls (202 men, 266 women). Mini Nutritional Assessment (MNA), anthropometric (height, weight, BMI), bioelectrical (R, Xc) and biochemical variables (serum albumin) were assessed. Bioelectrical characteristics were significantly different in the patients with mild-moderate AD with respect to controls, indicating low body cell mass (men, T2= 12.8; women, T2=34.9; p Alzheimer's disease is characterized by a tendency to malnutrition, present even in the mild-moderate stages, and a tendency to dehydration that appears in the severe stage. The BIVA technique is a promising tool for the screening and monitoring of nutrition and hydration status in Alzheimer's disease.

  3. Bioelectrical Impedance among Rural Bangladeshi Women during Pregnancy and in the Postpartum Period

    Science.gov (United States)

    Shaikh, Saijuddin; Ali, Hasmot; Labrique, Alain B.; Shamim, Abu Ahmed; Rashid, Mahbubur; Mehra, Sucheta; Christian, Parul; West, Keith P.

    2011-01-01

    Properties of bioelectrical impedance analysis (BIA) reflect body-composition and may serve as stand-alone indicators of maternal health. Despite these potential roles, BIA properties during pregnancy and lactation in rural South Asian women have not been described previously, although pregnancy and infant health outcomes are often compromised. This paper reports the BIA properties among a large sample of pregnant and postpartum women of rural Bangladesh, aged 12-46 years, participating in a substudy of a community-based, placebo-controlled trial of vitamin A or beta-carotene supplementation. Anthropometry and single frequency (50 kHz) BIA were assessed in 1,435 women during the first trimester (≤12 weeks gestation), in 1,237 women during the third trimester (32-36 weeks gestation), and in 1,141 women at 12-18 weeks postpartum. Resistance and reactance were recorded, and impedance and phase angle were calculated. Data were examined cross-sectionally to maximize sample-size at each timepoint, and the factors relating to BIA properties were explored. Women were typically young, primiparous and lacking formal education (22.2±6.3 years old, 42.2% primiparous, and 39.7% unschooled among the first trimester participants). Weight (kg), resistance (Ω), and reactance (Ω) were 42.1±5.7, 688±77, and 73±12 in the first trimester; 47.7±5.9, 646±77, and 64±12 in the third trimester; and 42.7±5.6, 699±79, and 72±12 postpartum respectively. Resistance declined with age and increased with body mass index. Resistance was higher than that observed in other, non-Asian pregnant populations, likely reflecting considerably smaller body-volume among Bangladeshi women. Resistance and reactance decreased in advanced stage of pregnancy as the rate of gain in weight increased, returning to the first trimester values by the three months postpartum. Normative distributions of BIA properties are presented for rural Bangladeshi women across a reproductive cycle that may be related

  4. Evaluation of bioelectrical impedance analysis for identifying overweight individuals at increased cardiometabolic risk: a cross-sectional study.

    Science.gov (United States)

    Lamb, Maxine J E; Byrne, Christopher D; Wilson, James F; Wild, Sarah H

    2014-01-01

    To investigate whether bioelectrical impedance analysis could be used to identify overweight individuals at increased cardiometabolic risk, defined as the presence of metabolic syndrome and/or diabetes. Cross-sectional study of a Scottish population including 1210 women and 788 men. The diagnostic performance of thresholds of percentage body fat measured by bioelectrical impedance analysis to identify people at increased cardiometabolic risk was assessed using receiver-operating characteristic curves. Odds ratios for increased cardiometabolic risk in body mass index categories associated with values above compared to below sex-specific percentage body fat thresholds with optimal diagnostic performance were calculated using multivariable logistic regression analyses. The validity of bioelectrical impedance analysis to measure percentage body fat in this population was tested by examining agreement between bioelectrical impedance analysis and dual-energy X-ray absorptiometry in a subgroup of individuals. Participants were aged 16-91 years and the optimal bioelectrical impedance analysis cut-points for percentage body fat for identifying people at increased cardiometabolic risk were 25.9% for men and 37.1% for women. Stratifying by these percentage body fat cut-points, the prevalence of increased cardiometabolic risk was 48% and 38% above the threshold and 24% and 19% below these thresholds for men and women, respectively. By comparison, stratifying by percentage body fat category had little impact on identifying increased cardiometabolic risk in normal weight and obese individuals. Fully adjusted odds ratios of being at increased cardiometabolic risk among overweight people with percentage body fat ≥ 25.9/37.1% compared with percentage body fat bioelectrical impedance analysis above a sex-specific threshold could be used in overweight people to identify individuals at increased cardiometabolic risk, who could benefit from risk factor management.

  5. Evaluation of Bioelectrical Impedance Spectroscopy for the Assessment of Extracellular Body Water

    Directory of Open Access Journals (Sweden)

    Sören Weyer

    2012-01-01

    Full Text Available This study evaluates bioelectrical impedance spectroscopy (BIS measurements to detect body fluid status. The multifrequency impedance measurements were performed in five female pigs. Animals were connected to an extracorporeal membrane oxygenation device during a lung disease experiment and fluid balance was recorded. Every 15 min the amount of fluid infusion and the weight of the urine drainage bag was recorded. From the fluid intake and output, the fluid balance was calculated. These data were compared with values calculated from a mathematical model, based on the extracellular tissue resistance and the Hanai Mixture theory. The extracellular tissue resistance was also measured with BIS. These experimental results strongly support the feasibility and clinical value of BIS for in vivo assessment of the hydration status.

  6. Tissue electrical properties measured by bioelectrical impedance analysis among healthy and sportsmen population

    Science.gov (United States)

    Kapica, Dominik; Warchulińska, Joanna; Jakubiak, Monika; Teter, Mariusz; Mlak, Radosław; Hałabiś, Magdalena; Wójcik, Waldemar; Małecka-Massalska, Teresa

    2015-09-01

    Introduction: Bioelectrical impedance analysis (BIA) is a useful tool to asses human body composition and nutrition status; multi-frequency BIA has a higher accuracy than single-frequency BIA. In our study a difference of impedance values (Z) at 5, 100 and 200 kHz and Z200/Z5 index between professional athletes and control group were determined. Methods: In this research 105 people were tested, divided into control group (72 people: 35 males and 37 females) and professional athletes (33 people: 16 males and 17 females). Impedance was measured at three frequency values - 5, 100 and 200 kHz; with received values the Z200/Z5 index was calculated. Results: In most compared subgroups impedance values showed significantly lower values in athletes than in control group (5 kHz - males: p=0.136, females: p=0.001, 100 kHz - males: p=0.039, females: pmales: p=0.047, females: pmales, p<0.0001 for females). Conclusion: Lower values of impedance and Z200/Z5 index indicates a better nutrition status and general health condition of athletes than in control group.

  7. A practical guide to bioelectrical impedance analysis using the example of chronic obstructive pulmonary disease

    Directory of Open Access Journals (Sweden)

    Mattiucci-Guehlke Muriel

    2011-04-01

    Full Text Available Abstract Bioelectrical impedance analysis (BIA is a simple, inexpensive, quick and non-invasive technique for measuring body composition. The clinical benefit of BIA can be further enhanced by combining it with bioelectrical impedance vector analysis (BIVA. However, there is a substantial lack of information on the practical aspects of BIA/BIVA for those primarily interested in learning how to use and interpret this method in practice. The purpose of this article is to provide some guidance on the use of BIA/BIVA with special attention to practical considerations. This report reflects the authors' practical experience with the use of single-frequency BIA in combination with BIVA, particularly in COPD patients. First, the method and principles of BIA/BIVA are briefly described. Then, a practice-oriented approach to the interpretation and analysis of characteristic examples of altered nutritional and fluid status as seen with BIA/BIVA in COPD patients (e.g. malnutrition in obese and underweight patients with COPD, water retention is presented. As our examples show BIA/BIVA is an attractive and easy-to-learn tool for quick nutritional assessment and is therefore of great clinical benefit in daily practice.

  8. Evaluation of segmental body composition by gender in obese children using bioelectric impedance analysis method

    Directory of Open Access Journals (Sweden)

    İhsan Çetin

    2015-12-01

    Full Text Available Objective: In this study, it was aimed to evaluate segmental body composition of children diagnosed with obesity using bioelectrical impedance analysis method in terms of different gender. Methods: 48 children, aged between 6-15 years, 21 of whom were boys while 27 were girls, diagnosed with obesity in Erciyes University Medical Faculty Department of Pediatric Endocrinology Outpatient Clinic were included in our study from April to June in 2011. Those over 95 percentile were defined as obese group. Tanita BC-418 device was used to analyze the body composition. Results: As a result of bioelectrical impedance analysis, lean body mass and body muscle mass were found to be statistically significantly higher in obese girls compared with obese boys. However, lean mass of the left arm, left leg muscle mass and basal metabolic rate were found to be statistically significantly lower in obese girls compared with obese boys. Conclusion: Consequently, it may be suggest that segmental analysis, where gender differences are taken into account, can provide proper exercise pattern and healthy way of weight loss in children for prevention of obesity and associated diseases including obesity and type 2 diabetics and cardiovascular diseases.

  9. A practical guide to bioelectrical impedance analysis using the example of chronic obstructive pulmonary disease.

    Science.gov (United States)

    Walter-Kroker, Anja; Kroker, Axel; Mattiucci-Guehlke, Muriel; Glaab, Thomas

    2011-04-21

    Bioelectrical impedance analysis (BIA) is a simple, inexpensive, quick and non-invasive technique for measuring body composition. The clinical benefit of BIA can be further enhanced by combining it with bioelectrical impedance vector analysis (BIVA). However, there is a substantial lack of information on the practical aspects of BIA/BIVA for those primarily interested in learning how to use and interpret this method in practice. The purpose of this article is to provide some guidance on the use of BIA/BIVA with special attention to practical considerations.This report reflects the authors' practical experience with the use of single-frequency BIA in combination with BIVA, particularly in COPD patients. First, the method and principles of BIA/BIVA are briefly described. Then, a practice-oriented approach to the interpretation and analysis of characteristic examples of altered nutritional and fluid status as seen with BIA/BIVA in COPD patients (e.g. malnutrition in obese and underweight patients with COPD, water retention) is presented.As our examples show BIA/BIVA is an attractive and easy-to-learn tool for quick nutritional assessment and is therefore of great clinical benefit in daily practice.

  10. Measurement of lean body mass using bioelectrical impedance analysis: a consideration of the pros and cons.

    Science.gov (United States)

    Sergi, Giuseppe; De Rui, Marina; Stubbs, Brendon; Veronese, Nicola; Manzato, Enzo

    2017-08-01

    The assessment of body composition has important applications in the evaluation of nutritional status and estimating potential health risks. Bioelectrical impedance analysis (BIA) is a valid method for the assessment of body composition. BIA is an alternative to more invasive and expensive methods like dual-energy X-ray absorptiometry, computerized tomography, and magnetic resonance imaging. Bioelectrical impedance analysis is an easy-to-use and low-cost method for the estimation of fat-free mass (FFM) in physiological and pathological conditions. The reliability of BIA measurements is influenced by various factors related to the instrument itself, including electrodes, operator, subject, and environment. BIA assumptions beyond its use for body composition are the human body is empirically composed of cylinders, FFM contains virtually all the water and conducting electrolytes in the body, and its hydration is constant. FFM can be predicted by BIA through equations developed using reference methods. Several BIA prediction equations exist for the estimation of FFM, skeletal muscle mass (SMM), or appendicular SMM. The BIA prediction models differ according to the characteristics of the sample in which they have been derived and validated in addition to the parameters included in the multiple regression analysis. In choosing BIA equations, it is important to consider the characteristics of the sample in which it has been developed and validated, since, for example, age- and ethnicity-related differences could sensitively affect BIA estimates.

  11. Postoperative Changes in Body Composition After Pancreaticoduodenectomy Using Multifrequency Bioelectrical Impedance Analysis.

    Science.gov (United States)

    Mikamori, Manabu; Miyamoto, Atsushi; Asaoka, Tadafumi; Maeda, Sakae; Hama, Naoki; Yamamoto, Kazuyoshi; Hirao, Motohiro; Ikeda, Masataka; Sekimoto, Mitsugu; Doki, Yuichiro; Mori, Masaki; Nakamori, Shoji

    2016-03-01

    Nutritional status is one of the most important clinical determinants of outcome after surgery. The aim of this study was to compare changes in the body composition of patients undergoing pancreaticoduodenectomy (PD), distal gastrectomy (DG), or total gastrectomy (TG). The parameters of body composition were measured using multifrequency bioelectrical impedance analysis with an inBody 720 (Biospace Inc. Tokyo. Japan) in 60 patients who had undergone PD (n = 18), DG (n = 30), or TG (n = 12). None of the patients had recurrence or were treated with chemotherapy. Changes between the preoperative data and results and those obtained 12 months after surgery were evaluated. Twelve months after surgery, the body weight change in the PD group was significantly lower than in the TG and DG groups (-1.2 ± 3.8 vs -7.4 ± 4.4 and -4.0 ± 3.2 kg, respectively; p < 0.01 vs TG, p < 0.05 vs DG). The body weight change correlated with the fat mass change in all groups. The type and extent of surgery has a different effect on long-term body weight and body composition. Bioelectric impedance analysis can be used to assess body composition and may be useful for nutritional assessment in patients who have undergone these surgeries.

  12. A practical guide to bioelectrical impedance analysis using the example of chronic obstructive pulmonary disease

    Science.gov (United States)

    2011-01-01

    Bioelectrical impedance analysis (BIA) is a simple, inexpensive, quick and non-invasive technique for measuring body composition. The clinical benefit of BIA can be further enhanced by combining it with bioelectrical impedance vector analysis (BIVA). However, there is a substantial lack of information on the practical aspects of BIA/BIVA for those primarily interested in learning how to use and interpret this method in practice. The purpose of this article is to provide some guidance on the use of BIA/BIVA with special attention to practical considerations. This report reflects the authors' practical experience with the use of single-frequency BIA in combination with BIVA, particularly in COPD patients. First, the method and principles of BIA/BIVA are briefly described. Then, a practice-oriented approach to the interpretation and analysis of characteristic examples of altered nutritional and fluid status as seen with BIA/BIVA in COPD patients (e.g. malnutrition in obese and underweight patients with COPD, water retention) is presented. As our examples show BIA/BIVA is an attractive and easy-to-learn tool for quick nutritional assessment and is therefore of great clinical benefit in daily practice. PMID:21510854

  13. Smartphone-Based Bioelectrical Impedance Analysis Devices for Daily Obesity Management.

    Science.gov (United States)

    Choi, Ahyoung; Kim, Justin Younghyun; Jo, Seongwook; Jee, Jae Hwan; Heymsfield, Steven B; Bhagat, Yusuf A; Kim, Insoo; Cho, Jaegeol

    2015-09-02

    Current bioelectric impedance analysis (BIA) systems are often large, cumbersome devices which require strict electrode placement on the user, thus inhibiting mobile capabilities. In this work, we developed a handheld BIA device that measures impedance from multiple frequencies (5 kHz~200 kHz) with four contact electrodes and evaluated the BIA device against standard body composition analysis systems: a dual-energy X-ray absorptiometry (DXA) system (GE Lunar Prodigy, GE Healthcare, Buckinghamshire, UK) and a whole-body BIA system (InBody S10, InBody, Co. Ltd, Seoul, Korea). In the study, 568 healthy participants, varying widely in body mass index, age, and gender, were recruited at two research centers: the Samsung Medical Center (SMC) in South Korea and the Pennington Biomedical Research Center (PBRC) in the United States. From the measured impedance data, we analyzed individual body fat and skeletal muscle mass by applying linear regression analysis against target reference data. Results indicated strong correlations of impedance measurements between the prototype pathways and corresponding InBody S10 electrical pathways (R = 0.93, p 0.728 (paired t-test), DXA mean body fat 29.45 ± 10.77 kg, estimated body fat 29.52 ± 12.53 kg). Thus, this portable BIA system shows a promising ability to estimate an individual's body composition that is comparable to large stationary BIA systems.

  14. [Research on Constant-current Characteristics of Howland Current Source Used in Bioelectrical Impedance Detection].

    Science.gov (United States)

    Lin, Xingjian; Zhao, Weijie; Liu, Xiaojuan; Li, Lihua

    2015-04-01

    This study aims to analyze and improve Howland current source circuit and to study the constant current source of alternating current with high output impedance and high stability. A simulation study was carried out on the constant-current characteristics of Howland current source from two aspects of resistance match value and the selection of Op amp parameters, and then the output impedance was analyzed. The simulation experiment showed that when it was with the best matched resistance, the constant-current characteristics of Howland current source was better. Op amp parameters could affect the constant-current characteristics of Howland current source. In Howland current source circuit, the current source after parameter optimization had better output impedance and load capacity. The results showed that there was the best matched resistance in the selection by Howland current source. The Op amp with large broadband, high slew rate and open loop gain, and wide range of power supply voltage is more suitable for the bioelectrical impedance detection circuit.

  15. Bioelectrical impedance analysis in clinical practice: implications for hepatitis C therapy BIA and hepatitis C

    Directory of Open Access Journals (Sweden)

    Kahraman Alisan

    2010-08-01

    Full Text Available Abstract Background Body composition analysis using phase angle (PA, determined by bioelectrical impedance analysis (BIA, reflects tissue electrical properties and has prognostic value in liver cirrhosis. Objective of this prospective study was to investigate clinical use and prognostic value of BIA-derived phase angle and alterations in body composition for hepatitis C infection (HCV following antiviral therapy. Methods 37 consecutive patients with HCV infection were enrolled, BIA was performed, and PA was calculated from each pair of measurements. 22 HCV genotype 3 patients treated for 24 weeks and 15 genotype 1 patients treated for 48 weeks, were examined before and after antiviral treatment and compared to 10 untreated HCV patients at 0, 24, and 48 weeks. Basic laboratory data were correlated to body composition alterations. Results Significant reduction in body fat (BF: 24.2 ± 6.7 kg vs. 19.9 ± 6.6 kg, genotype1; 15.4 ± 10.9 kg vs. 13.2 ± 12.1 kg, genotype 3 and body cell mass (BCM: 27.3 ± 6.8 kg vs. 24.3 ± 7.2 kg, genotype1; 27.7 ± 8.8 kg vs. 24.6 ± 7.6 kg, genotype 3 was found following treatment. PA in genotype 3 patients was significantly lowered after antiviral treatment compared to initial measurements (5.9 ± 0.7° vs. 5.4 ± 0.8°. Total body water (TBW was significantly decreased in treated patients with genotype 1 (41.4 ± 7.9 l vs. 40.8 ± 9.5 l. PA reduction was accompanied by flu-like syndromes, whereas TBW decline was more frequently associated with fatigue and cephalgia. Discussion BIA offers a sophisticated analysis of body composition including BF, BCM, and TBW for HCV patients following antiviral regimens. PA reduction was associated with increased adverse effects of the antiviral therapy allowing a more dynamic therapy application.

  16. Development of an equation for estimating appendicular skeletal muscle mass in Japanese older adults using bioelectrical impedance analysis.

    Science.gov (United States)

    Yoshida, Daisuke; Shimada, Hiroyuki; Park, Hyuntae; Anan, Yuya; Ito, Tadashi; Harada, Atsushi; Suzuki, Takao

    2014-10-01

    Bioelectrical impedance analysis has been reported to have high reliability and accuracy in assessing body composition. However, equations for estimating appendicular skeletal muscle mass are population-specific, and few have been developed for older Japanese adults. Thus, the purpose of the present study was to develop and validate an estimate equation for appendicular skeletal muscle mass using bioelectrical impedance analysis. A total of 250 older adults aged 65 years and older participated in this study. Appendicular skeletal muscle mass was measured using dual-energy X-ray absorptiometry, and bioelectrical resistance was measured using a multifrequency bioelectrical impedance analyzer. Multiple regression analysis was applied to derive sex-specific estimation formulae using bioelectrical impedance analysis, and a Bland-Altman analysis was used to test agreement. The cross-validation results showed that the slopes and intercepts of the regression lines were approximately one and zero, respectively, and the coefficients of determination and standard errors of the estimate of the newly developed equations were similar between the two groups. Thus, the single sex-specific equations were developed using all participants as follows. Men: appendicular skeletal muscle mass=0.197 × (impedance index) +0.179 × (weight) -0.019 (R(2)  =0.87, standard error of the estimate=0.98 kg). Women: appendicular skeletal muscle mass=0.221 × (impedance index) +0.117 × (weight) +0.881 (R(2)  =0.89, standard error of the estimate=0.81 kg). These new equations offer a valid option for assessing appendicular skeletal muscle mass in older Japanese adults. © 2014 Japan Geriatrics Society.

  17. Body Composition Comparison: Bioelectric Impedance Analysis with Dual-Energy X-Ray Absorptiometry in Adult Athletes

    Science.gov (United States)

    Company, Joe; Ball, Stephen

    2010-01-01

    The primary purpose of this study was to investigate the accuracy of the DF50 (ImpediMed Ltd, Eight Mile Plains, Queensland, Australia) bioelectrical impedance analysis device using dual-energy x-ray absorptiometry as the criterion in two groups: endurance athletes and power athletes. The secondary purpose was to develop accurate body fat…

  18. Comparison of Bioelectrical Impedance and Skinfolds with Hydrodensitometry in the Assessment of Body Composition in Healthy Young Adults

    Science.gov (United States)

    Rutherford, W. J.; Diemer, Gary A.; Scott, Eric D.

    2011-01-01

    Bioelectrical impedance analysis (BIA) is a widely used method for estimating body composition, yet issues concerning its validity persist in the literature. The purpose of this study was to validate percentage of body fat (BF) values estimated from BIA and skinfold (SF) with those obtained from hydrodensitometry (HD). Percent BF values measured…

  19. Prediction of fat-free body mass from bioelectrical impedance and anthropometry among 3-year-old children using DXA

    DEFF Research Database (Denmark)

    Ejlerskov, Katrine Tschentscher; Jensen, Signe Marie; Christensen, Line B

    2014-01-01

    For 3-year-old children suitable methods to estimate body composition are sparse. We aimed to develop predictive equations for estimating fat-free mass (FFM) from bioelectrical impedance (BIA) and anthropometry using dual-energy X-ray absorptiometry (DXA) as reference method using data from 99...

  20. Validity of bioelectrical impedance analysis to assess fat-free mass in head and neck cancer patients: an exploratory study

    NARCIS (Netherlands)

    Jan L.N. Roodenburg; Dr Harriët Jager-Wittenaar; Jan Pruim; Carrie P. Earthman; Pieter U. Dijkstra; Bernard F.A. M. van der Laan; Johannes A. Langendijk; W.P. Krijnen

    2013-01-01

    Bioelectrical impedance analysis (BIA) may be used to assess fet free mass (FFM) with reasonable validity based on mean-level comparisons, but differences between BIA and DXA may vary by about 4 kg in an individual patient. These results require confirmation in a larger sample of HNC patients. (Head

  1. Early changes of abdominal adiposity detected with weekly dual bioelectrical impedance analysis during calorie restriction.

    Science.gov (United States)

    Ida, Midori; Hirata, Masakazu; Odori, Shinji; Mori, Eisaku; Kondo, Eri; Fujikura, Junji; Kusakabe, Toru; Ebihara, Ken; Hosoda, Kiminori; Nakao, Kazuwa

    2013-09-01

    To elucidate early change of intra-abdominal fat in response to calorie restriction in patients with obesity by weekly evaluation using a dual bioelectrical impedance analysis (Dual BIA) instrument. For 67 Japanese patients with obesity, diabetes, or metabolic syndrome, intra-abdominal fat area (IAFA), initially with both Dual BIA and computed tomography (CT), and in subsequent weeks of calorie restriction, with Dual BIA were measured. IAFA by Dual BIA (Dual BIA-IAFA) correlated well with IAFA by CT (CT-IAFA) in obese patients (r = 0.821, P obese patients and demonstrated a substantially larger change of IAFA compared with changes of BW and WC in early weeks. This observation corroborates the significance of evaluating IAFA as a biomarker for obesity, and indicates the clinical usefulness of the Dual BIA instrument. Copyright © 2013 The Obesity Society.

  2. Use of bioelectrical impedance analysis in the evaluation, treatment, and prevention of overweight and obesity.

    Science.gov (United States)

    Ricciardi, Richard; Talbot, Laura A

    2007-05-01

    To present an overview of bioelectrical impedance analysis (BIA) and to familiarize nurse practitioners (NPs) with the potential benefits of using BIA in prevention, monitoring, and long-term follow-up of healthy individuals and those with chronic conditions (e.g., obesity). Original research articles and comprehensive review articles identified through Medline, CINAHL, OVID, and electrical engineering databases. Obtaining serial measurements of percent body fat using BIA can identify patients at greatest health risk and gives NPs an additional tool to assess treatment response in patients seeking to lose or maintain body weight and/or increase muscle mass. Traditionally, height/weight tables and body mass index have been used to assess body composition and diagnose overweight and obesity. More recently, BIA has emerged as a portable and simple-to-operate instrument to evaluate body composition in the clinical setting.

  3. Body composition measures of obese adolescents by the deuterium oxide dilution method and by bioelectrical impedance.

    Science.gov (United States)

    Resende, C M M; Camelo Júnior, J S; Vieira, M N C M; Ferriolli, E; Pfrimer, K; Perdoná, G S C; Monteiro, J P

    2011-11-01

    The objectives of the present study were to describe and compare the body composition variables determined by bioelectrical impedance (BIA) and the deuterium dilution method (DDM), to identify possible correlations and agreement between the two methods, and to construct a linear regression model including anthropometric measures. Obese adolescents were evaluated by anthropometric measures, and body composition was assessed by BIA and DDM. Forty obese adolescents were included in the study. Comparison of the mean values for the following variables: fat body mass (FM; kg), fat-free mass (FFM; kg), and total body water (TBW; %) determined by DDM and by BIA revealed significant differences. BIA overestimated FFM and TBW and underestimated FM. When compared with data provided by DDM, the BIA data presented a significant correlation with FFM (r = 0.89; P obese adolescents determined by DDM can be predicted by using the measures provided by BIA through a regression equation.

  4. Pendelluft diagnosed from ventilator weaning indexes obtained through bioelectrical impedance tomography: a case report.

    Science.gov (United States)

    Lopes, Fabiana Aparecida; Souza, Lidiane Andrade Monteiro de; Bernardi, Juliana Tavares Neves; Rocha, Carlos Eduardo; Figueiredo, Luciana Castilho de; Agostini, Ana Paula Ragonete Dos Anjos; Dragosavac, Desanka; Faez, Daniela Cristina Dos Santos

    2017-01-01

    Today, through major technological advances in diagnostic resources within medicine, evaluation and monitoring of clinical parameters at the patient's bedside in intensive care units (ICUs) has become possible. This case report presents results and interpretations from predictive mechanical ventilation weaning indexes obtained through monitoring using chest electrical bioimpedance tomography. These indexes included maximum inspiratory pressure, maximum expiratory pressure, shallow breathing index and spontaneous breathing test. These were correlated with variations in tidal volume variables, respiratory rate, mean arterial pressure and peripheral oxygen saturation. Regarding the air distribution behavior in the pulmonary parenchyma, the patient showed the pendelluft phenomenon. Pendelluft occurs due to the time constant (product of the airways resistance and compliance) asymmetry between adjacent lung. Bioelectrical impedance tomography can help in weaning from mechanical ventilation, as in the case presented here. Pendelluft was defined as a limitation during the weaning tests.

  5. Validation of bioelectrical-impedance analysis as a measurement of change in body composition in obesity

    Energy Technology Data Exchange (ETDEWEB)

    Kushner, R.F.; Kunigk, A.; Alspaugh, M.; Andronis, P.T.; Leitch, C.A.; Schoeller, D.A. (Univ. of Chicago, IL (USA))

    1990-08-01

    The bioelectrical-impedance-analysis (BIA) method accurately measures body composition in weight-stable subjects. This study validates the use of BIA to measure change in body composition. Twelve obese females underwent weight loss at a mean rate of 1.16 kg/wk. Body composition was measured by deuterium oxide dilution (D2O), BIA, and skinfold anthropometry (SFA) at baseline and at 5% decrements in weight. Highly significant correlations were obtained between D2O and BIA (r = 0.971) and between D2O and SFA (r = 0.932). Overall, BIA predicted change in fat-free mass with greater accuracy (to 0.4 kg) and precision (+/- 1.28 kg) than did anthropometry (to 0.8 kg and +/- 2.58 kg, respectively). We conclude that BIA is a useful clinical method for measuring change in body composition.

  6. Prediction of whole-body and segmental body composition by bioelectrical impedance in morbidly obese subjects.

    Science.gov (United States)

    Jiménez, Amanda; Omaña, Wilberto; Flores, Lílliam; Coves, María José; Bellido, Diego; Perea, Verónica; Vidal, Josep

    2012-04-01

    Validated equations for body composition analysis using bioelectrical impedance (BIA) in morbidly obese (MO) subjects are scarce. Thus, our aim was todevelop new equations from physical and BIA parameters to estimate whole-body and segmental body composition inMO subjects, with dual-energy X-ray absorptiometry(DXA) as the reference method. A cross-sectional study on 159 Caucasian MO subjects (female 78%, age 43.5 ± 11.8 years, BMI 45.6 ± 4.9 kg/m2) divided in two groups was conducted: model building cohort (n = 110) and model validation cohort (n 0 49). Stepwise regression analysis was used to develop specific fat free mass (FFM) and fat mass (FM) equations. Gender, body weight, and height2/impedance accounted, respectively, for 89.4% (p impedance, and waist and hip circumferences (respectively, R2 adjusted: 0.657, 0.776, and 0.770; p < 0.001). The new equations derived from physical and BIA parameters provide accurate estimates of body composition in MO subjects.

  7. Drug and bioactive molecule screening based on a bioelectrical impedance cell culture platform.

    Science.gov (United States)

    Ramasamy, Sakthivel; Bennet, Devasier; Kim, Sanghyo

    2014-01-01

    This review will present a brief discussion on the recent advancements of bioelectrical impedance cell-based biosensors, especially the electric cell-substrate impedance sensing (ECIS) system for screening of various bioactive molecules. The different technical integrations of various chip types, working principles, measurement systems, and applications for drug targeting of molecules in cells are highlighted in this paper. Screening of bioactive molecules based on electric cell-substrate impedance sensing is a trial-and-error process toward the development of therapeutically active agents for drug discovery and therapeutics. In general, bioactive molecule screening can be used to identify active molecular targets for various diseases and toxicity at the cellular level with nanoscale resolution. In the innovation and screening of new drugs or bioactive molecules, the activeness, the efficacy of the compound, and safety in biological systems are the main concerns on which determination of drug candidates is based. Further, drug discovery and screening of compounds are often performed in cell-based test systems in order to reduce costs and save time. Moreover, this system can provide more relevant results in in vivo studies, as well as high-throughput drug screening for various diseases during the early stages of drug discovery. Recently, MEMS technologies and integration with image detection techniques have been employed successfully. These new technologies and their possible ongoing transformations are addressed. Select reports are outlined, and not all the work that has been performed in the field of drug screening and development is covered.

  8. The potential of classic and specific bioelectrical impedance vector analysis for the assessment of sarcopenia and sarcopenic obesity.

    Science.gov (United States)

    Marini, Elisabetta; Buffa, Roberto; Saragat, Bruno; Coin, Alessandra; Toffanello, Elena Debora; Berton, Linda; Manzato, Enzo; Sergi, Giuseppe

    2012-01-01

    The aim of this paper is to investigate whether bioelectrical impedance vector analysis (BIVA) can be a suitable technique for the assessment of sarcopenia. We also investigate the potential use of specific BIVA as an indicator of sarcopenic obesity. The sample comprised 207 free-living elderly individuals of both sexes, aged 65 to 93 years. Anthropometric and bioelectrical measurements were taken according to standard criteria. The "classic" and "specific" BIVA procedures, which respectively correct bioelectrical values for body height and body geometry, were used. Dual energy X-ray absorptiometry (DXA) was used as the reference method for identifying sarcopenic and obese sarcopenic individuals. Bioelectrical and DXA values were compared using Student's t-test and Hotelling's T(2) test, as well as Pearson's correlation coefficient. According to classic BIVA, sarcopenic individuals of both sexes showed higher values of resistance/height (R/H; p impedance/height (Z/H; p bioelectrical differences between sarcopenic and sarcopenic obese men (T(2) = 13.4, p obese individuals. BIVA detected muscle-mass variations in sarcopenic individuals, and specific BIVA was able to discriminate sarcopenic individuals from sarcopenic obese individuals. These procedures are promising tools for screening for presarcopenia, sarcopenia, and sarcopenic obesity in routine practice.

  9. Bioelectrical impedance with different equations versus deuterium oxide dilution method for the inference of body composition in healthy older persons.

    Science.gov (United States)

    Pfrimer, K; Moriguti, J C; Lima, N K C; Marchini, J S; Ferriolli, E

    2012-02-01

    There is no consensus regarding the accuracy of bioimpedance for the determination of body composition in older persons. This study aimed to compare the assessment of lean body mass of healthy older volunteers obtained by the deuterium dilution method (reference) with those obtained by two frequently used bioelectrical impedance formulas and one formula specifically developed for a Latin-American population. A cross-sectional study. Twenty one volunteers were studied, 12 women, with mean age 72±6.7 years. Urban community, Ribeirão Preto, Brazil. Fat free mass was determined, simultaneously, by the deuterium dilution method and bioelectrical impedance; results were compared. In bioelectrical impedance, body composition was calculated by the formulas of Deuremberg, Lukaski and Bolonchuck and Valencia et al. Lean body mass of the studied volunteers, as determined by bioelectrical impedance was 37.8±9.2 kg by the application of the Lukaski e Bolonchuk formula, 37.4±9.3 kg (Deuremberg) and 43.2±8.9 kg (Valencia et. al.). The results were significantly correlated to those obtained by the deuterium dilution method (41.6±9.3 Kg), with r=0.963, 0.932 and 0.971, respectively. Lean body mass obtained by the Valencia formula was the most accurate. In this study, lean body mass of older persons obtained by the bioelectrical impedance method showed good correlation with the values obtained by the deuterium dilution method. The formula of Valencia et al., developed for a Latin-American population, showed the best accuracy.

  10. Lipid and moisture content modeling of amphidromous Dolly Varden using bioelectrical impedance analysis

    Science.gov (United States)

    Stolarski, J.T.; Margraf, F.J.; Carlson, J.G.; Sutton, T.M.

    2014-01-01

    The physiological well-being or condition of fish is most commonly estimated from aspects of individual morphology. However, these metrics may be only weakly correlated with nutritional reserves stored as lipid, the primary form of accumulated energy in fish. We constructed and evaluated bioelectrical impedance analysis (BIA) models as an alternative method of assessing condition in amphidromous Dolly Varden Salvelinus malma collected from nearshore estuarine and lotic habitats of the Alaskan Arctic. Data on electrical resistance and reactance were collected from the lateral and ventral surfaces of 192 fish, and whole-body percent lipid and moisture content were determined using standard laboratory methods. Significant inverse relationships between temperature and resistance and reactance prompted the standardization of these data to a constant temperature using corrective equations developed herein. No significant differences in resistance or reactance were detected among spawning and nonspawning females after accounting for covariates, suggesting that electrical pathways do not intersect the gonads. Best-fit BIA models incorporating electrical variables calculated from the lateral and ventral surfaces produced the strongest associations between observed and model-predicted estimates of proximate content. These models explained between 6% and 20% more of the variability in laboratory-derived estimates of proximate content than models developed from single-surface BIA data and 32% more than models containing only length and weight data. While additional research is required to address the potential effects of methodological variation, bioelectrical impedance analysis shows promise as a way to provide high-quality, minimally invasive estimates of Dolly Varden lipid or moisture content in the field with only small increases in handling time.

  11. [ABDOMINAL BIOELECTRICAL IMPEDANCE ANALYSIS AND ANTHROPOMETRY FOR PREDICTING METABOLIC SYNDROME IN MIDDLE AGED MEN].

    Science.gov (United States)

    Fernández-Vázquez, Rosalía; Millán Romero, Ángel; Barbancho, Miguel Ángel; Alvero-Cruz, José Ramón

    2015-09-01

    central obesity has a higher risk of metabolic syndrome. The present work aimed to study the relationship of trunk fat and the visceral fat index, and other anthropometric indices in relation to the metabolic syndrome in middle aged male Methods: design: transversal descriptive and correlational study. 75 male, volunteers who have access to a medical assessment, with an age range of 21 to 59 years, from different professions. Weight, height, body mass index, waist circumference, gluteal circumference, waist-to-hip ratio, waist-to-height ratio, trunk fat and visceral fat level by bioelectrical abdominal impedance analysis with Tanita AB-140 (ViScan) and biochemical markers: fasting glucose, total cholesterol, and triglycerides. Likewise, the systolic and diastolic blood pressure was measured. there are significant correlations of anthropometric measurements with trunk fat and visceral fat level and the same with biochemical variables. Receptor-operator curves (ROC curve) analysis shows that the cutoff points from which arises the metabolic syndrome are 32.7% of trunk fat and a level of visceral fat of 13 with a high sensitivity and specificity, attaining the same cut-off points for the metabolic syndrome and obesity status. trunk fat and visceral fat levels determined by bioelectrical abdominal impedance analysis, values are variables very sensitive and specific for the detection of metabolic syndrome and obesity, though not over the variables and anthropometric indices. In the condition of the overweight, trunk fat and visceral fat level are more predictive than anthropometric measures. Copyright AULA MEDICA EDICIONES 2014. Published by AULA MEDICA. All rights reserved.

  12. Reliability, Validity, and Diagnostic Value of a Pediatric Bioelectrical Impedance Analysis Scale.

    Science.gov (United States)

    Kabiri, Laura S; Hernandez, Daphne C; Mitchell, Katy

    2015-10-01

    Accurate body composition assessment is critical to identify children who are overfat or obese. Unlike BMI measures, bioelectrical impedance analysis (BIA) differentiates between lean and fat mass. However, bioelectrical impedance analysis has historically had questionable reliability and validity in children. The aim of this study was to determine the reliability, validity, and diagnostic value of a portable BIA scale (Tanita BF-689; Tanita Corporation, Tokyo, Japan) designed specifically for use within the pediatric population. Fifty-five children (males = 26; females = 29) had percent body fat (%BF) assessed twice using BIA and once using dual-energy X-ray absorptiometry (DEXA). Intraclass correlation coefficients (ICCs) were calculated for reliability. Mean difference and limits of agreement were calculated for convergent validity. Sensitivity/specificity for healthy, overfat, and obese classification were assessed. Test-retest ICC was 0.999 (0.999, 0.999). The ICC comparing BIA and DEXA for %BF was 0.788 (-0.167, 0.942). Mean difference between BIA and DEXA was -6.75% (limits of agreement = -0.04%; -13.46%). No gender or proportional bias was observed. Sensitivity/specificity for healthy, overfat, and obese classification were 0.67/0.65, 0.22/0.78, and 0.43/1.0, respectively. The Tanita BF-689 demonstrates excellent test-retest reliability, moderately strong absolute agreement with DEXA, and high specificity for overfat and obese classification. Compared to DEXA, the BF-689 is an accurate, portable, and efficient means of assessing %BF in elementary school children.

  13. The relationship between nocturnal polyuria and the distribution of body fluid: assessment by bioelectric impedance analysis.

    Science.gov (United States)

    Torimoto, Kazumasa; Hirayama, Akihide; Samma, Shoji; Yoshida, Katsunori; Fujimoto, Kiyohide; Hirao, Yoshihiko

    2009-01-01

    Increased nocturnal urinary volume is closely associated with nocturia. We investigated the relationship between nocturnal polyuria and the variation of body fluid distribution during the daytime using bioelectric impedance analysis. A total of 34 men older than 60 years were enrolled in this study. A frequency volume chart was recorded. Nocturnal polyuria was defined as a nocturnal urine volume per 24-hour production of greater than 0.35 (the nocturnal polyuria index). Bioelectric impedance analysis was performed 4 times daily at 8 and 11 a.m., and 5 and 9 p.m. using an InBody S20 body composition analyzer (BioSpace, Seoul, Korea). A significant difference was found in mean +/- SEM 24-hour urine production per fat-free mass between the groups with and without nocturnal polyuria (17.8 +/- 1.4 vs 7.7 +/- 0.9 ml/kg). The increase in fluid in the legs compared with the volume at 8 a.m. was significantly larger at 5 p.m., while there was no difference in the arms or trunk. Nocturnal urine volume significantly correlated with the difference in fluid volume in the legs (r = 0.527, p = 0.0019) and extracellular fluid volume (r = 0.3844, p = 0.0248) between the volumes at 8 a.m. and 9 p.m. Overproduction of urine per fat-free mass leads to nocturnal polyuria. Extracellular fluid accumulates as edema in the legs during the day in patients with nocturnal polyuria. The volume of accumulated extracellular fluid correlates with nocturnal urine volume. We suggest that leg edema is the source of nocturnal urine volume and decreasing edema may cure nocturnal polyuria.

  14. Does bioelectrical impedance analysis accurately estimate the condition of threatened and endangered desert fish species?

    Science.gov (United States)

    Dibble, Kimberly L.; Yard, Micheal D.; Ward, David L.; Yackulic, Charles B.

    2017-01-01

    Bioelectrical impedance analysis (BIA) is a nonlethal tool with which to estimate the physiological condition of animals that has potential value in research on endangered species. However, the effectiveness of BIA varies by species, the methodology continues to be refined, and incidental mortality rates are unknown. Under laboratory conditions we tested the value of using BIA in addition to morphological measurements such as total length and wet mass to estimate proximate composition (lipid, protein, ash, water, dry mass, energy density) in the endangered Humpback Chub Gila cypha and Bonytail G. elegans and the species of concern Roundtail Chub G. robusta and conducted separate trials to estimate the mortality rates of these sensitive species. Although Humpback and Roundtail Chub exhibited no or low mortality in response to taking BIA measurements versus handling for length and wet-mass measurements, Bonytails exhibited 14% and 47% mortality in the BIA and handling experiments, respectively, indicating that survival following stress is species specific. Derived BIA measurements were included in the best models for most proximate components; however, the added value of BIA as a predictor was marginal except in the absence of accurate wet-mass data. Bioelectrical impedance analysis improved the R2 of the best percentage-based models by no more than 4% relative to models based on morphology. Simulated field conditions indicated that BIA models became increasingly better than morphometric models at estimating proximate composition as the observation error around wet-mass measurements increased. However, since the overall proportion of variance explained by percentage-based models was low and BIA was mostly a redundant predictor, we caution against the use of BIA in field applications for these sensitive fish species.

  15. Combined assessment of nutritional status in patients with peritoneal dialysis using bioelectrical impedance vectors and malnutrition inflammation score.

    Science.gov (United States)

    Muñoz-Pérez, Elia; Espinosa-Cuevas, María De Los Ángeles; Miranda-Alatriste, Paola Vanessa; Correa-Rotter, Ricardo; Atilano-Carsi, Ximena

    2017-10-24

    Protein energy wasting (PEW) is a common syndrome in patients with chronic kidney disease, related to changes in hydration status, decreased food intake and inflammation. There are several tools for the assessment and diagnosis of such alterations. Bioimpedance vector analysis (BIVA) assess the state of nutrition and hydration, but not the inflammatory component, while the malnutrition inflammation score (MIS) comprises the inflammatory and nutritional factors, but not the state of hydration. The aim of the study was to determine the concordance between MIS and BIVA to assess nutritional status in peritoneal dialysis patients. We studied 50 patients on peritoneal dialysis which underwent  bioelectrical impedance measurements with an empty peritoneal cavity, also MIS was applied and biochemical parameters were evaluated. The prevalence of malnutrition with VIBE and MIS was 38% and 24% respectively. Statistically significant differences in body mass index (BMI) and phase angle between normally nourished and wasted patients by both methods were found. Body composition, biochemical parameters and impedance vectors were not statistically different between normally nourished and wasted patients. Concordance between methods was 0.314 (p = 0.019). Combined nutritional assessment with MIS and BIVA is necessary for the diagnosis of protein energy wasting syndrome in patients undergoing peritoneal dialysis.

  16. Smartphone-Based Bioelectrical Impedance Analysis Devices for Daily Obesity Management

    Directory of Open Access Journals (Sweden)

    Ahyoung Choi

    2015-09-01

    Full Text Available Current bioelectric impedance analysis (BIA systems are often large, cumbersome devices which require strict electrode placement on the user, thus inhibiting mobile capabilities. In this work, we developed a handheld BIA device that measures impedance from multiple frequencies (5 kHz~200 kHz with four contact electrodes and evaluated the BIA device against standard body composition analysis systems: a dual-energy X-ray absorptiometry (DXA system (GE Lunar Prodigy, GE Healthcare, Buckinghamshire, UK and a whole-body BIA system (InBody S10, InBody, Co. Ltd, Seoul, Korea. In the study, 568 healthy participants, varying widely in body mass index, age, and gender, were recruited at two research centers: the Samsung Medical Center (SMC in South Korea and the Pennington Biomedical Research Center (PBRC in the United States. From the measured impedance data, we analyzed individual body fat and skeletal muscle mass by applying linear regression analysis against target reference data. Results indicated strong correlations of impedance measurements between the prototype pathways and corresponding InBody S10 electrical pathways (R = 0.93, p < 0.0001. Additionally, body fat estimates from DXA did not yield significant differences (p > 0.728 (paired t-test, DXA mean body fat 29.45 ± 10.77 kg, estimated body fat 29.52 ± 12.53 kg. Thus, this portable BIA system shows a promising ability to estimate an individual’s body composition that is comparable to large stationary BIA systems.

  17. Prediction of Maximal Oxygen Uptake by Bioelectrical Impedance Analysis in Overweight Adolescents

    Science.gov (United States)

    Roberts, Mary D.; Drinkard, Bart; Ranzenhofer, Lisa M.; Salaita, Christine G.; Sebring, Nancy G.; Brady, Sheila M.; Pinchbeck, Carrie; Hoehl, Julie; Yanoff, Lisa B.; Savastano, David M.; Han, Joan C.; Yanovski, Jack A.

    2011-01-01

    BACKGROUND Maximal oxygen uptake (VO2max), the gold standard for measurement of cardiorespiratory fitness, is frequently difficult to assess in overweight individuals due to physical limitations. Reactance and resistance measures obtained from bioelectrical impedance analysis (BIA) have been suggested as easily obtainable predictors of cardiorespiratory fitness, but the accuracy with which ht2/Z can predict VO2max has not previously been examined in overweight adolescents. METHODS The impedance index was used as a predictor of VO2max in 87 overweight girls and 47 overweight boys ages 12 to 17 with mean BMI of 38.6 ± 7.3 and 42.5 ± 8.2 in girls and boys respectively. The Bland Altman procedure assessed agreement between predicted and actual VO2max. RESULTS Predicted VO2max was significantly correlated with measured VO2max (r2=0.48, pimpedance index was highly correlated with VO2max in overweight adolescents. However, using BIA data to predict maximal oxygen uptake over-predicted VO2max at low levels of oxygen consumption and under-predicted VO2max at high levels of oxygen consumption. This magnitude bias, along with the large limits of agreement of BIA-derived predicted VO2max, limit its usefulness in the clinical setting for overweight adolescents. PMID:19861930

  18. Maternal body fluid composition in uncomplicated pregnancies and preeclampsia: a bioelectrical impedance analysis.

    Science.gov (United States)

    Staelens, Anneleen S; Vonck, Sharona; Molenberghs, Geert; Malbrain, Manu L N G; Gyselaers, Wilfried

    2016-09-01

    Body fluid composition changes during the course of pregnancy and there is evidence to suggest that these changes are different in uncomplicated pregnancies compared to hypertensive pregnancies. The aim of this study was to evaluate the changes in maternal body fluid composition during the course of an uncomplicated pregnancy and to assess differences in uncomplicated pregnancies versus hypertensive pregnancies by using a bio-impedance analysis technique. Body fluid composition of each patient was assessed using a multiple frequency bioelectrical impedance analyser. Measurements were performed in 276 uncomplicated pregnancies, 34 patients with gestational hypertension, 35 with late onset preeclampsia and 11 with early onset preeclampsia. Statistical analysis was performed at nominal level α=0.05. A longitudinal linear mixed model based analysis was performed for longitudinal evolutions, and ANOVA with a post-hoc Bonferroni was used to identify differences between groups. Measurements showed that total body water (TBW), intracellular (ICW) and extracellular water (ECW) and ECW/ICW significantly increase during the course of pregnancy. Late onset preeclampsia is associated with a higher TBW and ECW as compared to uncomplicated pregnancies, the ECW/ICW ratio is higher in preeclamptic patients compared to uncomplicated pregnancies and gestational hypertension, and ICW is not different between groups. Body fluid composition changes differently during the course of uncomplicated pregnancies versus hypertensive pregnancies. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  19. Visceral fat estimation method by bioelectrical impedance analysis and causal analysis

    Science.gov (United States)

    Nakajima, Hiroshi; Tasaki, Hiroshi; Tsuchiya, Naoki; Hamaguchi, Takehiro; Shiga, Toshikazu

    2011-06-01

    It has been clarified that abdominal visceral fat accumulation is closely associated to the lifestyle disease and metabolic syndrome. The gold standard in medical fields is visceral fat area measured by an X-ray computer tomography (CT) scan or magnetic resonance imaging. However, their measurements are high invasive and high cost; especially a CT scan causes X-ray exposure. They are the reasons why medical fields need an instrument for viscera fat measurement with low invasive, ease of use, and low cost. The article proposes a simple and practical method of visceral fat estimation by employing bioelectrical impedance analysis and causal analysis. In the method, abdominal shape and dual impedances of abdominal surface and body total are measured to estimate a visceral fat area based on the cause-effect structure. The structure is designed according to the nature of abdominal body composition to be fine-tuned by statistical analysis. The experiments were conducted to investigate the proposed model. 180 subjects were hired to be measured by both a CT scan and the proposed method. The acquired model explained the measurement principle well and the correlation coefficient is 0.88 with the CT scan measurements.

  20. Development and evaluation of a multi-frequency bioelectrical impedance analysis analyzer for estimating acupoint composition.

    Science.gov (United States)

    Kim, Soo-Byeong; Lee, Na-Ra; Shin, Tae-Min; Lee, Yong-Heum

    2014-02-01

    The purpose of this study was to suggest a new method of estimating acupoint compositions by using a multi-frequency bioelectrical impedance analysis (MF-BIA) method at 5 kHz, 50 kHz and 200 kHz within 2 cm of acupoints divided into local segments. To verify the system developed, we confirmed the stable occurrence of a constant current at every frequency, regardless of the impedance connected to the electrodes. Moreover, we found left and right distal bicep brachii aponeurosis to be identical by using ultrasound imaging, and we analyzed the repeatability of the findings by making 10 consecutive sets of measurements (p > 0.05). To evaluate the practical use of the acupoint composition, we used the MF-BIA analyzer to measure the left and right LU3, LU4, and LU9 at the lung meridian. We confirmed that the potentials generated were equal to the changes in the cell membrane function, which were caused by the applied frequency (p 0.05). Hence, we conclude that the MF-BIA analyzer can be used to estimate the acupoint composition based on the acupoint state. Copyright © 2014. Published by Elsevier B.V.

  1. Body Composition Analysis by Using Bioelectrical Impedance in a Young Healthy Chinese Population: Methodological Considerations.

    Science.gov (United States)

    Chen, Wei; Jiang, Hua; Yang, Jiong-Xian; Yang, Hao; Liu, Jing-Min; Zhen, Xiu-Yuan; Feng, Lian-Jun; Yu, Jian-Chun

    2017-06-01

    To develop a new bioelectrical impedance analysis (BIA) model for analyzing body composition by using isotope dilution, magnetic resonance imaging (MRI), and dual-energy X-ray absorptiometry (DEXA) as the reference methods in young healthy Chinese populations. Thirty healthy participants were enrolled. Their body composition was analyzed using BIA and 3 reference methods. We established a model that uniformed data from 3 references methods (isotope, MRI, and DEXA) into 1 formula. This model was further validated with 209 participants. The following BIA body composition adjustment model was developed: [Formula: see text], where X represents the impedance index; when K = 1, 2, and 3, Y represents total body water, fat mass, and bone mass, respectively. The prediction accuracy of this formula was 93.3%. By incorporating the data matrix, the protein mass was calculated using BIA: [Formula: see text]. In the verification part of this study, the lean body mass measured using DEXA and BIA was 43.02 ± 8.34 kg and 45.85 ± 8.81 kg, respectively. Analysis indicated that the model fit was extremely favorable ( R 2 = .9997, P < .001). The accuracy of BIA measurement on body composition and protein mass is significantly improved by our work.

  2. Lean body mass estimation by bioelectrical impedance analysis: a four-site cross-validation study.

    Science.gov (United States)

    Segal, K R; Van Loan, M; Fitzgerald, P I; Hodgdon, J A; Van Itallie, T B

    1988-01-01

    This study validated further the bioelectrical impedance analysis (BIA) method for body composition estimation. At four laboratories densitometrically-determined lean body mass (LBMd) was compared with BIA in 1567 adults (1069 men, 498 women) aged 17-62 y and with 3-56% body fat. Equations for predicting LBMd from resistance measured by BIA, height, weight, and age were obtained for the men and women. Application of each equation to the data from the other labs yielded small reductions in R values and small increases in SEEs. Some regression coefficients differed among labs but these differences were eliminated after adjustment for differences among labs in the subjects' body fatness. All data were pooled to derive fatness-specific equations for predicting LBMd: the resulting R values ranged from 0.907 to 0.952 with SEEs of 1.97-3.03 kg. These results confirm the validity of BIA and indicate that the precision of predicting LBM from impedance can be enhanced by sex- and fatness-specific equations.

  3. Critical factors and their impact on bioelectrical impedance analysis in children: a review.

    Science.gov (United States)

    Brantlov, Steven; Ward, Leigh C; Jødal, Lars; Rittig, Søren; Lange, Aksel

    2017-01-01

    Several guidelines for bioelectrical impedance analysis (BIA) have been prepared for adults, but not for children. For that reason, there is a pressing need to develop a consensus set of guidelines to facilitate standardisation of BIA in this important group. This review provides an introduction to BIA, highlights critical factors that may impact on BIA and identifies areas where there is a need for further research in order to increase the quality of impedance measurements and prediction of body composition in children. Although the results of this review highlights a lack of studies in children to provide definitive BIA guidelines, the technique has, however, still proven valuable for body composition assessment in ill and healthy children. To fill the gaps in our knowledge, future studies should focus on methodological issues, particularly with regard to hydration, voiding, clothing, skin preparation and body position. The review may advantageously be used as a checklist in the planning of future studies. Finally, this review forms the basis for the development of guidelines for BIA assessment in this particular group; a task appropriately to be undertaken by scientific societies within the field.

  4. Assessment of hydration status using bioelectrical impedance vector analysis in critical patients with acute kidney injury.

    Science.gov (United States)

    Hise, Ana Cláudia da Rosa; Gonzalez, Maria Cristina

    2018-04-01

    The state of hyperhydration in critically ill patients with acute kidney injury (AKI) is associated with increased mortality. Bioelectrical impedance vector analysis (BIVA) appears to be a viable method to access the fluid status of critical patients but has never been evaluated in critical patients with AKI. The objective of this study is to evaluate the hydration status measured using BIVA in critical patients under intensive care at the time of AKI diagnosis and to correlate this measurement with mortality. We assessed the fluid status measured using BIVA in 224 critical patients at the time of AKI diagnosis and correlated it with mortality. To interpret the results, BIVA Software 2002 was used to plot the data from the patients studied on the 95% confidence ellipses of the RX c plane for comparisons between groups (non-survivors, survivors). Variables such as mechanical ventilation, vasoactive drug, and sepsis, among others, were collected. The impedance vector analysis conducted using BIVA Software 2002 indicated changes in the body compositions of patients according to the 95% confidence ellipse between the vectors R/H and X c /H of the group of survivors and the group of deceased patients. Hotelling's test (T 2  = 21.2) and the F test (F = 10.6) revealed significant differences (p critically ill patients with AKI. Copyright © 2017 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.

  5. Evaluation of bioelectrical impedance analysis for identifying overweight individuals at increased cardiometabolic risk: a cross-sectional study.

    Directory of Open Access Journals (Sweden)

    Maxine J E Lamb

    Full Text Available To investigate whether bioelectrical impedance analysis could be used to identify overweight individuals at increased cardiometabolic risk, defined as the presence of metabolic syndrome and/or diabetes.Cross-sectional study of a Scottish population including 1210 women and 788 men. The diagnostic performance of thresholds of percentage body fat measured by bioelectrical impedance analysis to identify people at increased cardiometabolic risk was assessed using receiver-operating characteristic curves. Odds ratios for increased cardiometabolic risk in body mass index categories associated with values above compared to below sex-specific percentage body fat thresholds with optimal diagnostic performance were calculated using multivariable logistic regression analyses. The validity of bioelectrical impedance analysis to measure percentage body fat in this population was tested by examining agreement between bioelectrical impedance analysis and dual-energy X-ray absorptiometry in a subgroup of individuals.Participants were aged 16-91 years and the optimal bioelectrical impedance analysis cut-points for percentage body fat for identifying people at increased cardiometabolic risk were 25.9% for men and 37.1% for women. Stratifying by these percentage body fat cut-points, the prevalence of increased cardiometabolic risk was 48% and 38% above the threshold and 24% and 19% below these thresholds for men and women, respectively. By comparison, stratifying by percentage body fat category had little impact on identifying increased cardiometabolic risk in normal weight and obese individuals. Fully adjusted odds ratios of being at increased cardiometabolic risk among overweight people with percentage body fat ≥ 25.9/37.1% compared with percentage body fat <25.9/37.1% as a reference were 1.93 (95% confidence interval: 1.20-3.10 for men and 1.79 (1.10-2.92 for women.Percentage body fat measured using bioelectrical impedance analysis above a sex

  6. A high-speed bioelectrical impedance spectroscopy system based on the digital auto-balancing bridge method

    International Nuclear Information System (INIS)

    Li, Nan; Xu, Hui; Zhou, Zhou; Wang, Wei; Qiao, Guofeng; Li, David D-U

    2013-01-01

    A novel bioelectrical impedance spectroscopy system based on the digital auto-balancing bridge method improved from the conventional analogue auto-balancing method is presented for bioelectrical impedance measurements. The hardware of the proposed system consists of a reference source, a null detector, a variable source, a field programmable gate array, a clock generator, a flash and a USB controller. Software implemented in the field programmable gate array includes three major blocks: clock management, peripheral control and digital signal processing. The principle and realization of the least-mean-squares-based digital auto-balancing algorithm is introduced in detail. The performances of our system were examined by comparing with a commercial impedance analyzer. The results reveal that the proposed system has high speed (less than 3.5 ms per measurement) and high accuracy in the frequency range of 1 kHz–10 MHz. Compared with the commercial instrument based on the traditional analogue auto-balancing method, our system shows advantages in measurement speed, compactness and flexibility, making it suitable for various bioelectrical impedance measurement applications. (paper)

  7. A high-speed bioelectrical impedance spectroscopy system based on the digital auto-balancing bridge method

    Science.gov (United States)

    Li, Nan; Xu, Hui; Wang, Wei; Zhou, Zhou; Qiao, Guofeng; D-U Li, David

    2013-06-01

    A novel bioelectrical impedance spectroscopy system based on the digital auto-balancing bridge method improved from the conventional analogue auto-balancing method is presented for bioelectrical impedance measurements. The hardware of the proposed system consists of a reference source, a null detector, a variable source, a field programmable gate array, a clock generator, a flash and a USB controller. Software implemented in the field programmable gate array includes three major blocks: clock management, peripheral control and digital signal processing. The principle and realization of the least-mean-squares-based digital auto-balancing algorithm is introduced in detail. The performances of our system were examined by comparing with a commercial impedance analyzer. The results reveal that the proposed system has high speed (less than 3.5 ms per measurement) and high accuracy in the frequency range of 1 kHz-10 MHz. Compared with the commercial instrument based on the traditional analogue auto-balancing method, our system shows advantages in measurement speed, compactness and flexibility, making it suitable for various bioelectrical impedance measurement applications.

  8. Bioelectrical impedance outperforms waist circumference for predicting cardiometabolic risk in Congolese hypertensive subjects: a cross-sectional study.

    Science.gov (United States)

    Katchunga, Philippe Bianga; Bapolisi, Achile Mwira; M'Buyamba-Kabangu, Jean-René; Hermans, Michel P

    2015-03-10

    Waist circumference threshold values used in sub-Saharan Africa correspond to those of European populations and are therefore inappropriate. Thus, they may over predict insulin resistance, especially in hypertensive Africans, in whom there is often no association between blood pressure and insulin resistance. Using bioelectrical impedance measurement in sub-Saharan Africa could possibly be advantageous to overcome the shortcomings of waist circumference measurement. The aim of this study was to evaluate the contribution of body composition estimation by bioelectrical impedance to predict cardiometabolic risk in Congolese hypertensive subjects. Cardiovascular profiling and body composition analysis by bioelectrical impedance was measured in 400 patients (men = 40%; age = 51.1 ± 12.6 years). Patients were diagnosed with a metabolic syndrome (MS) according to the IDF Criteria with and without the "blood pressure" criterion to remove any confounding autocorrelation bias, a visceral fat-MS (with and without the "blood pressure" criterion) being defined by the presence of ≥ 2 criteria with the precondition of excess visceral fat defined by a bio impedance measurement score >10/30. Total cardiovascular risk was assessed using the criteria of Framingham-2008. The frequencies of enlarged waist circumference (71.9% vs 68.9%, p = 0.52) and IDF-MS without blood pressure criterion (24.9% vs 21.9%, p = 0.48) were similar among hypertensive vs. non hypertensive however excess visceral fat (57.6% vs 33.8%, p 0.05). Pending the determination of thresholds values for pathological waist circumference adapted to sub-Saharan populations, using bioelectrical impedance measurement may contribute to better characterize the cardiometabolic risk and the insulin resistant phenotype of hypertensive sub-Saharan Africans.

  9. Impact of eating and drinking on body composition measurements by bioelectrical impedance.

    Science.gov (United States)

    Androutsos, O; Gerasimidis, K; Karanikolou, A; Reilly, J J; Edwards, C A

    2015-04-01

    Bioelectrical impedance analysis would be a more practical tool to measure body composition in clinical settings, dietetic practice and epidemiological studies if patients/subjects did not have to fast before measurements. The present study assessed whether the ingestion of food or drink had any biologically significant effect on bioimpedance measurements and body composition by the foot-to-foot method. Fifty-five healthy adults [30 males and 25 females; mean (SD) age 27.7 (7.1) years; mean (SD)body mass index 24 (3.8) kg m(-2)] were randomly assigned to a 2-day food trial (high-fat meal or high-carbohydrate meal) or a 2-day drink trial (water or high electrolyte drink). Body composition measurements were carried out in the fasting state, immediately after meal consumption and every 30 min for 2 h by the foot-to-foot single frequency bioimpedance technique. Bioimpedance increased significantly after the ingestion of food and fluid, although the changes were small. The electrolyte drink, high-fat and high-carbohydrate meals significantly increased the percentage body fat and fat mass. In all cases, the median percentage changes from baseline were approximately 1% in body fat percentage units. Although there were statistically significant changes in body composition estimates after food or drink consumption, these were small and within the imprecision of the impedance technique, and so are unlikely to be of clinical significance. The present study suggests that impedance measures of body fatness in clinical settings do not require strict adherence to fasting, and this should increase the opportunities for clinical application. © 2014 The British Dietetic Association Ltd.

  10. The Effect of the Menstrual Cycle on Body Composition Determined by Contact-Electrode Bioelectrical Impedance Analyzers.

    Science.gov (United States)

    Cumberledge, Emily A; Myers, Cassandra; Venditti, Jennifer J; Dixon, Curt B; Andreacci, Joseph L

    2018-01-01

    Bioelectrical impedance analysis (BIA) is a noninvasive and relatively inexpensive method of assessing body composition. Manufacturers of BIA technology recommend to avoid testing women when they perceive to be retaining water during the menstrual cycle. The purpose of the present investigation was to examine the effect of the menstrual cycle on body composition determined by contact-electrode BIA analyzers. Forty-three college-aged women volunteered to participate in this study (age=21.2 ± 1.1 years; body mass index = 24.0 ± 3.7 kg/m 2 ). Subjects had their body composition assessed using four different contact-electrode BIA analyzers during the following menstrual cycle phases: menstrual, follicular, early and late luteal. Regardless of the BIA analyzer used for the assessment, no significant differences in body composition measures were found between cycle phases. The results of this study indicate that the contact-electrode BIA devices used in this study can be used at any time during a woman's menstrual cycle without altering the body composition values.

  11. Assessment of body composition with bioelectrical impedance analysis in pregnant women with hyperemesis gravidarum before and after treatment.

    Science.gov (United States)

    Tazegül Pekin, A; Yılmaz, S A; Kerimoğlu, Ö Seçilmiş; Çelik, G; Doğan, N U; Beyhekim, H; Çelik, Ç

    2015-01-01

    More than half of pregnant women suffer from nausea and vomiting, in 0.5-1% of the pregnant women, if nausea and vomiting are severe and persistent, condition can progress to hyperemesis. We evaluated the fluid volume parameters in pregnant women with hyperemesis gravidarum, before and after treatment using the bioelectrical impedance vectors. A total of 70 pregnant women who had weight loss exceeding 5% of pre-pregnancy body weight were recruited for the study in the first trimester. The measurement of multi-frequency bioelectrical impedance analysis parameters was performed on the day of hospitalisation before any treatment and after treatment at 24 h and 72 h with the same procedure. Total body water, extracellular water, intracellular water, and fat-free mass index increased after treatment at 24 h (P hyperemesis gravidarum, significant body composition changes occur and fluid replacement therapy performed during a short period of time, such as 24 h, provides improvement in body composition.

  12. Evaluation of body composition in COPD patients using multifrequency bioelectrical impedance analysis

    Directory of Open Access Journals (Sweden)

    de Blasio F

    2016-09-01

    Full Text Available Francesca de Blasio,1 Francesco de Blasio,2,3 Giulia Miracco Berlingieri,2 Andrea Bianco,3,4 Marta La Greca,1 Frits M E Franssen,5 Luca Scalfi1 1Department of Public Health, Medical School, “Federico II” University of Naples, 2Respiratory Medicine and Pulmonary Rehabilitation Section, Clinic Center, Private Hospital, Naples, 3Department of Medicine and Health Sciences “V Tiberio”, University of Molise, Campobasso, 4Department of Cardio-Thoracic and Respiratory Sciences, Second University of Naples, Naples, Italy; 5Department of Research and Education, CIRO, Horn, the NetherlandsBackground: Multifrequency bioelectrical impedance analysis (MF-BIA is a technique that measures body impedance (Z at different frequencies (5, 10, 50, 100, and 250 kHz. Body composition may be estimated using empirical equations, which include BIA variables or, alternatively, raw BIA data may provide direct information on water distribution and muscle quality.Objectives: To compare raw MF-BIA data between COPD patients and controls and to study their relationship with respiratory and functional parameters in COPD patients.Methods: MF-BIA was performed (Human Im-Touch analyzer in 212 COPD patients and 115 age- and BMI-matched controls. Fat-free mass (FFM and fat mass were estimated from BIA data, and low- to high-frequency (5 kHz/250 kHz impedance ratio was calculated. Physical fitness, lung function and respiratory muscle strength were also assessed in COPD patients.Results: After adjusting for age, weight, and body mass index, FFM and the 5/250 impedance ratio were lower in COPD patients (P<0.001 and were negatively affected by disease severity. In both male and female patients, the 5/250 impedance ratio was significantly correlated mainly with age (r=−0.316 and r=−0.346, respectively. Patients with a 5/250 impedance ratio below median value had lower handgrip strength (P<0.001, 6-minute walk distance (P<0.005, respiratory muscle strength (P<0.005, forced

  13. Bioelectrical impedance outperforms waist circumference for predicting cardiometabolic risk in Congolese hypertensive subjects: a cross-sectional study

    OpenAIRE

    Katchunga, Philippe Bianga; Bapolisi, Achile Mwira; M?Buyamba-Kabangu, Jean-Ren?; Hermans, Michel P

    2015-01-01

    BACKGROUND: Waist circumference threshold values used in sub-Saharan Africa correspond to those of European populations and are therefore inappropriate. Thus, they may over predict insulin resistance, especially in hypertensive Africans, in whom there is often no association between blood pressure and insulin resistance. Using bioelectrical impedance measurement in sub-Saharan Africa could possibly be advantageous to overcome the shortcomings of waist circumference measurement. The aim of thi...

  14. Relationship between Height-Weight Difference Index and Body-Fat Percentage Estimated by Bioelectrical Impedance Analysis in Thai Adults

    OpenAIRE

    Juntaping, Kanokkarn; Chittawatanarat, Kaweesak; Prasitwattanaseree, Sukon; Chaijaruwanich, Jeerayut; Traisathit, Patrinee

    2017-01-01

    Introduction. The height-weight difference index (HWDI) is a new indicator for evaluating obesity status. While body-fat percentage (BF%) is considered to be the most accurate obesity evaluation tool, it is a more expensive method and more difficult to measure than the others. Objective. Our objectives were to find the relationship between HWDI and BF% and to find a BF% prediction model from HWDI in relation to age and gender. Method. Bioelectrical impedance analysis was used to measure BF% i...

  15. Prediction of fat-free body mass from bioelectrical impedance and anthropometry among 3-year-old children using DXA

    OpenAIRE

    Ejlerskov, Katrine T.; Jensen, Signe M.; Christensen, Line B.; Ritz, Christian; Michaelsen, Kim F.; Mølgaard, Christian

    2014-01-01

    For 3-year-old children suitable methods to estimate body composition are sparse. We aimed to develop predictive equations for estimating fat-free mass (FFM) from bioelectrical impedance (BIA) and anthropometry using dual-energy X-ray absorptiometry (DXA) as reference method using data from 99 healthy 3-year-old Danish children. Predictive equations were derived from two multiple linear regression models, a comprehensive model (height2/resistance (RI), six anthropometric measurements) and a s...

  16. The potential of classic and specific bioelectrical impedance vector analysis for the assessment of sarcopenia and sarcopenic obesity

    OpenAIRE

    Marini, Elisabetta; Buffa, Roberto; Saragat, Bruno; Coin, Alessandra; Toffanello, Elena Debora; Berton, Linda; Manzato, Enzo; Sergi, Giuseppe

    2012-01-01

    Elisabetta Marini,1 Roberto Buffa,1 Bruno Saragat,1 Alessandra Coin,2 Elena Debora Toffanello,2 Linda Berton,2 Enzo Manzato,2 Giuseppe Sergi21Department of Environmental and Life Sciences, University of Cagliari, Italy; 2Department of Medicine-DIMED, Geriatrics Section, University of Padua, ItalyPurpose: The aim of this paper is to investigate whether bioelectrical impedance vector analysis (BIVA) can be a suitable technique for the assessment of sarcopenia. We also investigate the potential ...

  17. A Pilot Randomized Trial Evaluating Lymphedema Self-Measurement with Bioelectrical Impedance, Self-Care Adherence, and Health Outcomes

    OpenAIRE

    Ridner, Sheila H.; Shih, Ya-Chen Tina; Doersam, Jennifer K.; Rhoten, Bethany Andrews; Schultze, Benjamin S.; Dietrich, Mary S.

    2014-01-01

    Background: Less than half of breast cancer survivors with lymphedema perform self-care as directed. Effective lymphedema self-care is required to obtain acceptable health outcomes. Self-Regulation Theory suggests that objective self-measurement of physiological conditions is necessary to promote self-regulation/self-care. Bioelectric Impedance Spectroscopy (BIS) represents a potential self-measurement method for arm lymphedema. The purpose of this pilot study was to examine the impact of arm...

  18. Application of segmental bioelectrical impedance spectroscopy to the assessment of skeletal muscle cell mass in elderly men.

    Science.gov (United States)

    Yamada, Yosuke; Matsuda, Kaori; Björkman, Mikko P; Kimura, Misaka

    2014-02-01

    It is important to assess not only the total skeletal muscle mass, but also the intracellular and extracellular compartments of skeletal muscle to examine the actual relationship between skeletal muscle mass and physical functions. Segmental bioelectrical impedance spectroscopy is a unique tool with which to assess intracellular and extracellular water in the limbs. The aim of the present study was to examine the application of segmental bioelectrical impedance spectroscopy to the assessment of skeletal muscle mass in the elderly. A total of 73 healthy elderly men and 20 elderly men requiring care and using an ambulatory day-care service of the public long-term care insurance system participated in the present study. The intracellular and extracellular water in the upper and lower legs were assessed by segmental bioelectrical impedance spectroscopy. The gait speed, grip strength and maximal isometric knee extension strength were measured. The elderly requiring care had significantly lower intracellular water than did healthy elderly in the upper and lower legs. A significant relative expansion of extracellular water against total water was observed in the elderly requiring care. Receiver operating characteristic curves showed that the area under the curve for the intracellular water index was similar to that for muscle strength in the discrimination of elderly requiring care. The elderly requiring care had a relative expansion of extracellular water in the legs, which could have masked actual muscle atrophy. Segmental bioelectrical impedance spectroscopy would be useful for the assessment of skeletal muscle cell mass and sarcopenia in the elderly. © 2014 Japan Geriatrics Society.

  19. Comparison of experimental and bioelectrical impedance analysis methods in calculation of dry weight in peritoneal dialysis patients

    Directory of Open Access Journals (Sweden)

    A Emami Naini

    2012-01-01

    Conclusion: The study showed that there is significant difference between the two methods. However, there was 98% direct correlation between them. It is concluded that bioelectrical impedance analysis could be a better alternative for accurate evaluation of dry weight in PD patients because it is a fast and cheap method and does not depend on examiner′s capability. Further studies based on the results of this method are recommended to consider this method as the gold standard.

  20. Evaluation of the usefulness of visceral fat area measurement by the bioelectrical impedance method during workplace health screening

    International Nuclear Information System (INIS)

    Igarashi, Chiyo

    2008-01-01

    In the field of occupational health, health guidance concerning obesity is often conducted in order to prevent lifestyle-related diseases. With recent awareness of the concept of metabolic syndrome, measurement of the visceral fat area (VFA) by CT has been useful for health guidance, but it is difficult in workplace health screening. Presently, the BMI (Body Mass Index), body fat percentage measured by the bioelectrical impedance method, and waist girth at the umbilical level (abdominal girth) are practical indices of obesity used in such health screening. In this study, VAF was measured in 590 clerical or sales workers in the manufacturing industry using a body fat meter capable of a visceral fat measurement by the bioelectrical impedance method. The relationship of this value to the results of biochemical tests and lifestyle was then evaluated using analysis of covariance structures. Analysis indicated that the risk of lifestyle-related disease was closely related to the degree of obesity. Among indices of the degree of obesity, VFA was more closely related than BMI or body fat percentage, and only slightly less closely related than abdominal girth to the risk of lifestyle-related diseases. Since VFA is effective in screening for latent obesity, health guidance based on digital data, and the subjects' body imaging, its measurement by the bioelectrical impedance method is considered useful for workplace health management. (author)

  1. Bioelectrical impedance self-measurement protocol development and daily variation between healthy volunteers and breast cancer survivors with lymphedema.

    Science.gov (United States)

    Ridner, Sheila H; Bonner, Candace M; Doersam, Jennifer K; Rhoten, Bethany A; Schultze, Benjamin; Dietrich, Mary S

    2014-03-01

    A significant percentage of breast cancer survivors are at risk for lymphedema for which lifelong self-care is required. Previous studies suggest that less than 50% of breast cancer survivors with lymphedema (BCS-LE) perform prescribed self-care tasks and that even wearing a compression sleeve, the most commonly reported self-care activity, is done irregularly. Reasons for poor self-care adherence include perceived lack of results from self-care (no available arm volume data) and perceived inability to manage the condition. A two-part pilot study was conducted to: 1) develop and determine the feasibility of a self-measurement protocol using a single frequency bioelectrical impedance device; and 2) examine daily variation in extracellular volume in healthy and lymphedematous limbs. Healthy and BCS-LE volunteers were recruited to refine and test a self-measurement protocol. Volunteers were trained in the use of the device and measured for 5 consecutive days in a laboratory setting. They were then given the device to use at home for an additional 5 consecutive days of self-measurement. All volunteers completed each scheduled home measurement. Daily variability in both groups was noted. Home self-measurement using bioelectrical impedance is feasible, acceptable, and captures change. This has implications for both self-care support and for the possibility of incorporating self-measurement using bioelectrical impedance in future clinical trials examining effectiveness of lymphedema treatment.

  2. Comparison of single- or multifrequency bioelectrical impedance analysis and spectroscopy for assessment of appendicular skeletal muscle in the elderly.

    Science.gov (United States)

    Yamada, Yosuke; Watanabe, Yuya; Ikenaga, Masahiro; Yokoyama, Keiichi; Yoshida, Tsukasa; Morimoto, Taketoshi; Kimura, Misaka

    2013-09-01

    Bioelectrical impedance analysis (BIA) is used to assess skeletal muscle mass, although its application in the elderly has not been fully established. Several BIA modalities are available: single-frequency BIA (SFBIA), multifrequency BIA (MFBIA), and bioelectrical impedance spectroscopy (BIS). The aim of this study was to examine the difference between SFBIA, MFBIA, and BIS for assessment of appendicular skeletal muscle strength in the elderly. A total of 405 elderly (74.2 ± 5.0 yr) individuals were recruited. Grip strength and isometric knee extension strength were measured. Segmental SFBIA, MFBIA, and BIS were measured for the arms and upper legs. Bioelectrical impedance indexes were calculated by squared segment length divided by impedance (L2/Z). Impedance at 5 and 50 kHz (Z5 and Z50) was used for SFBIA. Impedance of the intracellular component was calculated from MFBIA (Z250-5) and BIS (RICW). Correlation coefficients between knee extension strength and L2/Z5, L2/Z50, L2/RICW, and L2/Z250-5 of the upper legs were 0.661, 0.705, 0.790, and 0.808, respectively (P < 0.001). Correlation coefficients were significantly greater for MFBIA and BIS than SFBIA. Receiver operating characteristic curves showed that L2/Z250-5 and L2/RICW had significantly larger areas under the curve for the diagnosis of muscle weakness compared with L2/Z5 and L2/Z50. Very similar results were observed for grip strength. Our findings suggest that MFBIA and BIS are better methods than SFBIA for assessing skeletal muscle strength in the elderly.

  3. Validity of Four Commercial Bioelectrical Impedance Scales in Measuring Body Fat among Chinese Children and Adolescents

    Directory of Open Access Journals (Sweden)

    Lin Wang

    2015-01-01

    Full Text Available The aim of the study is to examine the validity in predicting body fat percentage (%BF of different bioelectrical impedance (BIA devices among Chinese children and adolescents. A total of 255 Chinese children and adolescents aged 9–19 years old participated in the study. %BF was assessed by BIA scales, namely, Biodynamics-310 (Model A, Tanita TBF-543 (Model B, Tanita BC-545 (Model C, and InBody 520 (Model D. Dual-energy X-ray absorptiometry (DXA was used as the criterion measurement. Lin’s concordance correlation coefficients of estimated %BF between Model A, Model B, Model C, and DXA showed poor agreements for both genders. Moderate agreements for %BF were found between DXA and Model D measurements. In boys, differences in %BF were found between DXA and Model B and Model C. No significant %BF differences were found between Model A, Model D, and DXA. However, the two BIA analyzers showed a significant positive correlation between the bias and average %BF between BIA and DXA. In girls, differences in %BF were observed between Model B, Model C, Model D, and DXA. Model A and DXA showed no significant differences of %BF; however, the bias and the average %BF between the BIA and DXA had a significant positive correlation. Using embedded equations in BIA devices should be validated in assessing the %BF of Chinese children and adolescents.

  4. Validity of Bioelectrical Impedance Analysis to Estimation Fat-Free Mass in the Army Cadets

    Directory of Open Access Journals (Sweden)

    Raquel D. Langer

    2016-03-01

    Full Text Available Background: Bioelectrical Impedance Analysis (BIA is a fast, practical, non-invasive, and frequently used method for fat-free mass (FFM estimation. The aims of this study were to validate predictive equations of BIA to FFM estimation in Army cadets and to develop and validate a specific BIA equation for this population. Methods: A total of 396 males, Brazilian Army cadets, aged 17–24 years were included. The study used eight published predictive BIA equations, a specific equation in FFM estimation, and dual-energy X-ray absorptiometry (DXA as a reference method. Student’s t-test (for paired sample, linear regression analysis, and Bland–Altman method were used to test the validity of the BIA equations. Results: Predictive BIA equations showed significant differences in FFM compared to DXA (p < 0.05 and large limits of agreement by Bland–Altman. Predictive BIA equations explained 68% to 88% of FFM variance. Specific BIA equations showed no significant differences in FFM, compared to DXA values. Conclusion: Published BIA predictive equations showed poor accuracy in this sample. The specific BIA equations, developed in this study, demonstrated validity for this sample, although should be used with caution in samples with a large range of FFM.

  5. V-dotO2max prediction from multi-frequency bioelectrical impedance analysis

    International Nuclear Information System (INIS)

    Stahn, Alexander; Strobel, Günther; Terblanche, Elmarie

    2008-01-01

    Bioelectrical impedance analysis (BIA) has been shown to be highly related to skeletal muscle mass and blood volume, both of which are important determinants of maximal oxygen uptake (V-dotO 2max ). The aim of the present study was therefore to investigate the ability of whole-body and segmental multi-frequency BIA to improve current nonexercise V-dotO 2max prediction models. Data for V-dotO 2max (mL min −1 ), anthropometry, self-reported physical activity (PA-R) and BIA were collected in 115 men and women. Multiple linear regression analysis (MLR) was used to develop the most parsimonious prediction model. Segmental BIA was not superior to whole-body measurements. Correlation coefficients between V-dotO 2max and resistance indices were significantly higher at 500 kHz compared to 50 kHz (p 2max (r = 0.89). After adjusting for age, gender and PA-R, MLR revealed that the inclusion of intracellular resistance index was slightly, but significantly (p 2max ( −1 ). In short, whole-body BIA marginally improves the accuracy of nonexercise V-dotO 2max prediction models and its advantage is most pronounced in individuals with particularly low V-dotO 2max

  6. Bioimpedance vector pattern in women with breast cancer detected by bioelectric impedance vector analysis. Preliminary observations.

    Science.gov (United States)

    Małecka-Massalska, Teresa; Chara, Krzysztof; Smolen, Agata; Kurylcio, Andrzej; Polkowski, Wojciech; Lupa-Zatwarnicka, Krystyna

    2012-01-01

    The study was conducted to evaluate soft tissue hydration and mass through pattern analysis of vector plots as height, normalized resistance, and reactance measurements by bioelectric impedance vector analysis (BIVA) in patients with breast cancer. Whole-body measurements were made with ImpediMed bioimpedance analysis SFB7 BioImp v1.55 (Pinkenba Qld 4008, Australia) in 68 adult, white, female subjects: 34 adult, white female (age 31-82) patients with breast cancer and 34 healthy volunteers matched by age, gender and BMI as a control group. The measurements were performed prior to oncological and surgical treatment, without the need for active nutritional interventions. Mean vectors of women with breast cancer versus the healthy women groups were characterized by a slight increase of the normalized resistance and reactance components (separate 95% confidence limits, p nutritional status of the patient prior to surgery. This quick assessment of the patient nutritional status can allow for early corrective intervention. Further observational research investigating these properties in larger groups would be beneficial to elucidate and/or confirm these findings.

  7. Association of Anthropometric and Bioelectrical Impedance Analysis Measures of Adiposity with High Molecular Weight Adiponectin Concentration.

    Science.gov (United States)

    Zeng, Wei-Fang; Li, Yan; Sheng, Chang-Sheng; Huang, Qi-Fang; Kang, Yuan-Yuan; Zhang, Lu; Wang, Shuai; Cheng, Yi-Bang; Li, Fei-Ka; Wang, Ji-Guang

    2016-01-01

    To investigate the relationship between adiposity measures and plasma concentration of high molecular weight (HMW) adiponectin. In a Chinese sample (n = 1081), we performed measurements of anthropometry and bioelectrical impedance analysis (BIA). We defined overweight and obesity as a body mass index between 24 and 27.4 kg/m² and ≥ 27.5 kg/m², respectively, and central obesity as a waist circumference ≥ 90 cm in men and ≥ 80 cm in women. Plasma HMW adiponectin concentration was measured by the ELISA method. Plasma HMW adiponectin concentration was significantly (P obesity (n = 60, 1.31 μg/mL and n = 82, 2.10 μg/mL, respectively) than normal weight subjects (n = 185, 2.07μg/mL and n = 368, 2.94 μg/mL, respectively) and in the presence of central obesity (n = 106, 1.28 μg/mL and n = 331, 2.12 μg/mL, respectively) than subjects with a normal waist circumference (n = 298, 1.74 μg/mL and n = 346, 2.74 μg/mL, respectively). In multiple regression analyses stratified for gender, adjusted for confounders and considered separately each of the adiposity measures, all adiposity measures were significantly (r -0.18 to -0.31, P obesity, such as waist-to-hip ratio, but not BIA measures, are independently associated with plasma adiponectin concentration.

  8. Adiposity and postural balance control: correlations between bioelectrical impedance and stabilometric signals in elderly Brazilian women

    Directory of Open Access Journals (Sweden)

    Míriam Raquel Meira Mainenti

    2011-01-01

    Full Text Available OBJECTIVE: The purpose of this study was to investigate the correlation between body adiposity and postural control in elderly women. INTRODUCTION: Aging and obesity account for a significant portion of healthcare spending. Life expectancy is increasing worldwide, and Rio de Janeiro has the largest proportion of elderly residents of all Brazilian states. METHODS: A total of 45 women underwent bioelectrical impedance analysis, waist circumference measurements, weight and height measurements, and stabilometric tests in eight different stance conditions (opened and closed bases with both eyes opened and closed and right and left tandem and unilateral stances with eyes opened. During unilateral stances, the number of hand or foot contacts was counted. RESULTS: Weight, body mass index, waist circumference, fat percentage, and fat mass showed statistically significant (p,0.05 and positive correlations with the number of contacts made during unilateral stances. The subjects with greater fat mass showed significantly higher anterior-posterior standard deviation and range when their eyes were closed. The sway area was also greater for this group in opened base when their eyes were closed. DISCUSSION: The results relating body adiposity and postural control can be explained by the difficulty of maintaining a greater quantity of body fat mass within the limits of the individual support base, especially while assuming a unilateral stance. CONCLUSION: The subjects with a greater fat mass exhibited poor balance control, indicating that body adiposity level was associated with postural control in the elderly women examined in the present study.

  9. Relationship between bioelectrical impedance analysis and body mass index in adolescent urban Nigerians.

    Science.gov (United States)

    Nwizu, S E; Njokanma, O F; Okoromah, C A; David, N A

    2011-01-01

    Body mass index is often used to assess adiposity but it does not differentiate between fat and non-fat components of body mass. However, body fat composition may be assessed using bioelectrical impedance analysis. The study aimed to relate body mass index to fat in the assessment of overweight and obesity among adolescent Nigerians. Adolescent pupils aged 10 years to 18 years from randomly selected secondary schools in Lagos, Nigeria were studied. Body mass index was calculated while percentage body fat was measured using Tanita body® fat scale model BF 681. Overweight and obesity were defined using age and sex specific criteria for body mass index and for body fat. There were 753 pupils {377(50.1%) males and 376(49.9%) females}. The overall mean values of body mass index for males and females were 18.1±2.72 and 18.9±3.41 (p obesity range had high body fat in comparison to 44.4% of males (p < 0.05). Body mass index is more related to body fat in adolescent females than in their male counterparts.

  10. Increased abdominal fat levels measured by bioelectrical impedance are associated with histological lesions of nonalcoholic steatohepatitis.

    Science.gov (United States)

    Margariti, Aikaterini; Kontogianni, Meropi D; Tileli, Nafsika; Georgoulis, Michael; Deutsch, Melanie; Zafeiropoulou, Rodessa; Tiniakos, Dina; Manios, Yannis; Pectasides, Dimitrios; Papatheodoridis, George V

    2015-08-01

    Abdominal fat is considered to play an important role in nonalcoholic fatty liver disease (NAFLD), although it is not adequately studied because abdominal fat levels cannot be estimated easily. In this study, associations between abdominal obesity, as assessed by abdominal bioelectrical impedance analysis (BIA), and the characteristics of patients with NAFLD were explored. Seventy-four consecutive NAFLD patients who underwent measurement of abdominal fat levels by BIA were included. Levels of abdominal fat 12.5 or less and more than 12.5 were considered to be average and increased, respectively. The mean±SD BMI was 30±4 kg/m and the mean abdominal fat levels were 16±5, whereas 26% of patients had average abdominal fat levels. Patients with average compared with those with increased abdominal fat levels were more frequently women (50 vs. 12%, P=0.001), had lower BMI (27±3 vs. 31±4 kg/m, Pobesity seem to represent strong risk factors for histological steatohepatitis.

  11. Adiposity and postural balance control: Correlations between bioelectrical impedance and stabilometric signals in elderly Brazilian women

    Science.gov (United States)

    Mainenti, Míriam Raquel Meira; de Carvalho Rodrigues, Érika; de Oliveira, Juliana Flávia; de Sá Ferreira, Arthur; Dias, Cristina Márcia; dos Santos Silva, André Luís

    2011-01-01

    OBJECTIVE: The purpose of this study was to investigate the correlation between body adiposity and postural control in elderly women. INTRODUCTION: Aging and obesity account for a significant portion of healthcare spending. Life expectancy is increasing worldwide, and Rio de Janeiro has the largest proportion of elderly residents of all Brazilian states. METHODS: A total of 45 women underwent bioelectrical impedance analysis, waist circumference measurements, weight and height measurements, and stabilometric tests in eight different stance conditions (opened and closed bases with both eyes opened and closed and right and left tandem and unilateral stances with eyes opened). During unilateral stances, the number of hand or foot contacts was counted. RESULTS: Weight, body mass index, waist circumference, fat percentage, and fat mass showed statistically significant (p<0.05) and positive correlations with the number of contacts made during unilateral stances. The subjects with greater fat mass showed significantly higher anterior-posterior standard deviation and range when their eyes were closed. The sway area was also greater for this group in opened base when their eyes were closed. DISCUSSION: The results relating body adiposity and postural control can be explained by the difficulty of maintaining a greater quantity of body fat mass within the limits of the individual support base, especially while assuming a unilateral stance. CONCLUSION: The subjects with a greater fat mass exhibited poor balance control, indicating that body adiposity level was associated with postural control in the elderly women examined in the present study. PMID:22179151

  12. Body composition by bioelectrical impedance analysis and prevalence of obesity in a school-age children.

    Science.gov (United States)

    Salas-Flores, Ricardo; González-Pérez, Brian; Cornejo-Barrera, Judith; Llanas-Rodríguez, José Daniel; Cruz-Hernández, Cosme

    2011-01-01

    the interest in the direct assessment of adiposity is increasing. The aim was to assess fat mass and lean mass by bioelectrical impedance, and to analyze the correlation between percentage Body Fat-body mass index and percentage Body Fat-WC, and determine the prevalence of overweight and obesity in a sample of school-age children. a cross-sectional study was performed in 360 children; differences between the sexes were assessed by independent t-test. Prevalence of overweight and obesity were calculated according to body mass index and two percentage body fat-based cutoffs. there was no significant gender difference in body mass index (p = 0.91), while the boys were both taller and presented more abdominal obesity but with lower mean percentage body fat (p obesity in boys (12.7 % and 17.7 %) than girls (12 % and 13.9 %). it is an urgent need to implement preventive actions among school children to decrease the prevalence of childhood obesity, which constitutes an important health problem in Mexico.

  13. Validity of Four Commercial Bioelectrical Impedance Scales in Measuring Body Fat among Chinese Children and Adolescents.

    Science.gov (United States)

    Wang, Lin; Hui, Stanley Sai-Chuen

    2015-01-01

    The aim of the study is to examine the validity in predicting body fat percentage (%BF) of different bioelectrical impedance (BIA) devices among Chinese children and adolescents. A total of 255 Chinese children and adolescents aged 9-19 years old participated in the study. %BF was assessed by BIA scales, namely, Biodynamics-310 (Model A), Tanita TBF-543 (Model B), Tanita BC-545 (Model C), and InBody 520 (Model D). Dual-energy X-ray absorptiometry (DXA) was used as the criterion measurement. Lin's concordance correlation coefficients of estimated %BF between Model A, Model B, Model C, and DXA showed poor agreements for both genders. Moderate agreements for %BF were found between DXA and Model D measurements. In boys, differences in %BF were found between DXA and Model B and Model C. No significant %BF differences were found between Model A, Model D, and DXA. However, the two BIA analyzers showed a significant positive correlation between the bias and average %BF between BIA and DXA. In girls, differences in %BF were observed between Model B, Model C, Model D, and DXA. Model A and DXA showed no significant differences of %BF; however, the bias and the average %BF between the BIA and DXA had a significant positive correlation. Using embedded equations in BIA devices should be validated in assessing the %BF of Chinese children and adolescents.

  14. Noninvasive Bioelectrical Impedance for Predicting Clinical Outcomes in Outpatients With Heart Failure.

    Science.gov (United States)

    Lyons, Kristin J; Bischoff, Michelle K; Fonarow, Gregg C; Horwich, Tamara B

    2017-03-01

    Noninvasive bioelectrical impedance analysis (BIA) has shown promise in acute heart failure (HF) management. To our knowledge, its use in predicting outcomes in outpatients with chronic HF patients has not been well described. BIA assessment of edema index was performed in 359 outpatients with HF using the InBody 520 scale. Edema index was calculated by dividing extracellular by total body water. Patients were stratified into those with low (≤0.39) and high (>0.39) edema indices. The outcome of interest was death, urgent transplant, or ventricular assist device over 2-year follow up. Patients with a high edema index were older, had higher B-type natriuretic peptide values and New York Heart Association Class. Patients with a high edema index had poorer outcomes (unadjusted hazard ratio 1.90, 95% confidence intervals 1.05-3.56). However, in multivariate analyses, a high edema index was not an independent predictor of outcomes (adjusted hazard ratio 1.21, 95% confidence interval 0.51-2.90). A high edema index using a bioimpedance scale in a HF clinic correlated with patient outcomes in unadjusted analyses, but was not a predictor of outcomes once other measures of HF severity are accounted for. As a noninvasive measure of volume status, use of BIA in a HF clinic may be beneficial in determining patient prognosis and treatment when other outcome predictors are not immediately available.

  15. Validation of a portable bioelectrical impedance analyzer for the assessment of body composition.

    Science.gov (United States)

    Karelis, Antony D; Chamberland, Gabriel; Aubertin-Leheudre, Mylène; Duval, Christian

    2013-01-01

    One of the major challenges in field research has been the difficulty to adequately measure body composition, such as % body fat and fat-free mass (FFM). Therefore, the purpose of the present study was to investigate the convergent validity of the portable bioelectrical impedance body composition analyzer, the Inbody 230, with dual X-ray absorptiometry (DXA) (General Electric Lunar Prodigy). The study population consisted of 145 men and women (age, 44.6 ± 20 years; BMI, 24.5 ± 3.8 kg·m(-2)). We measured body composition (fat mass, % body fat, total FFM, trunk FFM, and appendicular FFM) using DXA and the Inbody 230. Results show strong significant correlations between both methods for fat mass, % body fat, total FFM, and trunk FFM (r = 0.94-0.99). Furthermore, we showed a modest significant correlation between both methods for appendicular FFM (r = 0.63). Finally, as shown by Bland-Altman analysis, no significant biases were observed between Inbody 230 and DXA for fat mass, % body fat, and total FFM. However, trunk and appendicular FFM were shown to have significant biases between the Inbody 230 and DXA. In conclusion, the present study indicated that the portable Inbody 230 may be an acceptable device to measure fat mass, % body fat, and total FFM (except for women) in healthy adults. In addition, there appears to be a systematic bias for the estimation of trunk and appendicular FFM with the Inbody 230 in men and women.

  16. Measurement of nutritional status in simulated microgravity by bioelectrical impedance spectroscopy

    Science.gov (United States)

    Bartok, Cynthia; Atkinson, Richard L.; Schoeller, Dale A.

    2003-01-01

    The potential of bioelectrical impedance spectroscopy (BIS) for assessing nutritional status in spaceflight was tested in two head-down-tilt bed-rest studies. BIS-predicted extracellular water (ECW), intracellular water (ICW), and total body water (TBW) measured using knee-elbow electrode placement were compared with deuterium and bromide dilution (DIL) volumes in healthy, 19- to 45-yr-old subjects. BIS was accurate during 44 h of head-down tilt with mean differences (BIS - DIL) of 0-0.1 kg for ECW, 0.3-0.5 for ICW, and 0.4-0.6 kg for TBW (n = 28). At 44 h, BIS followed the within-individual change in body water compartments with a relative prediction error (standard error of the estimate/baseline volume) of 2.0-3.6% of water space. In the second study, BIS did not detect an acute decrease (-1.41 +/- 0.91 kg) in ICW secondary to 48 h of a protein-free, 800 kcal/day diet (n = 18). BIS's insensitivity to ICW losses may be because they were predominantly (65%) localized to the trunk and/or because there was a general failure of BIS to measure ICW independently of ECW and TBW. BIS may have potential for measuring nutritional status during spaceflight, but its limitations in precision and insensitivity to acute ICW changes warrant further validation studies.

  17. Bioelectrical Impedance May Predict Cell Viability During Ischemia and Reperfusion in Rat Liver

    Science.gov (United States)

    Cui, Mei Lan; Ahn, Hyun Soo; Kim, Jong Yeon; Shin, Hyoun Jin; Lee, Dong Shik; Kim, Hong Jin

    2010-01-01

    Ischemia and reperfusion (I/R) injury is a major cause of hepatic failure after liver surgery, but no method could monitor or predict it real-time during surgery. We measured bioelectrical impedance (BEI) and cell viability to assess the usefulness of BEI during I/R in rat liver. A 70% partial liver ischemia model was used. BEI was measured at various frequencies. Adenosine triphosphate (ATP) content, and palmitic acid oxidation rate were measured, and histological changes were observed in order to quantify liver cell viability. BEI changed significantly during ischemia at low frequency. In the ischemia group, BEI increased gradually during 60 min of ischemia and had a tendency to plateau thereafter. The ATP content decreased below 20% of the baseline level. In the I/R group, BEI recovered to near baseline level. After 24 hr of reperfusion, the ATP contents decreased to below 50% in 30, 60 and 120 min of ischemia and the palmitic acid metabolic rates decreased to 91%, 78%, and 74%, respectively, compared with normal liver. BEI may be a good tool for monitoring I/R during liver surgery. The liver is relatively tolerant to ischemia, however after reperfusion, liver cells may be damaged depending upon the duration of ischemia. PMID:20358001

  18. Bioelectrical impedance analysis for diagnosing sarcopenia and cachexia: what are we really estimating?

    Science.gov (United States)

    Gonzalez, Maria Cristina; Heymsfield, Steven B

    2017-04-01

    As reference methods are not available for identifying low skeletal muscle mass in clinical practice, the European Group on Sarcopenia in Older People the Asian Working Group for Sarcopenia and the International Consensus for Cancer Cachexia guidelines accept bioelectrical impedance analysis (BIA) as an option for sarcopenia and cachexia assessment. Using different BIA equations, several components that represent 'muscularity' can be assessed. Total skeletal muscle mass or appendicular skeletal muscle mass normalized in relation to height (skeletal muscle mass index or appendicular skeletal muscle index, respectively) is the most common term used in the consensus. These terms are similar, but they should not be used as synonymous. Both terms can be used to define sarcopenia, but adequate equations and cut-off values should be used according to the studied population. However, there is a disagreement between the sarcopenia definition assessed by using BIA from the European Group on Sarcopenia in Older People and Cachexia Consensus, and this can lead to an overestimation of sarcopenia and, consequently, cachexia. An effort should be made to standardize the terminology employed by the Societies to define low muscularity and sarcopenia by using BIA. Future validation studies may show the need for specific cut-off values for each population using this method. © 2017 The Authors. Journal of Cachexia, Sarcopenia and Muscle published by John Wiley & Sons Ltd on behalf of the Society on Sarcopenia, Cachexia and Wasting Disorders.

  19. Estimation of extracellular and total body water by multiple-frequency bioelectrical-impedance measurement

    Energy Technology Data Exchange (ETDEWEB)

    Segal, K.R.; Burastero, S.; Chun, A.; Coronel, P.; Pierson, R.N. Jr.; Wang, J. (Mount Sinai School of Medicine, New York, NY (USA))

    1991-07-01

    This study evaluated a new technology of bioelectrical-impedance (BI) measurement that makes use of multiple frequencies (5, 50, and 100 kHz) for estimation of extracellular and total body water. In 36 healthy males, resistance and reactance at three frequencies were compared with extra-cellular water (ECW) and total body water (TBW) determined by isotope dilution. ECW was best predicted by resistance measured at 5 kHz, corrected for height and weight (R = 0.930, SEE = 1.94 L) whereas TBW was best predicted by resistance at 100 kHZ and weight (R = 0.947, SEE = 2.64 L). Cross-validation analysis on two randomly selected subsets (n = 18 each) indicated that the prediction equations were reproducible and valid. Thus, BI at dual frequencies is valid for determination of body-water compartments and may be useful in the nutritional assessment of patients in whom body water and hydration is of clinical concern.

  20. Accuracy of segmental bioelectrical impedance analysis for predicting body composition in pre- and postmenopausal women.

    Science.gov (United States)

    Tanaka, Noriko I; Hanawa, Satoshi; Murakami, Haruka; Cao, Zhen-Bo; Tanimoto, Michiya; Sanada, Kiyoshi; Miyachi, Motohiko

    2015-01-01

    This study aimed to compare the accuracy for predicting body composition using single-frequent segmental bioelectrical impedance analysis (BIA) between pre- and postmenopausal women. A total f 559 Japanese women aged 30-88yr were divided into 4 groups by questionnaire: natural menopause, pathological menopause, regular menstruation, or irregular menstruation. The measurement values by dual-energy X-ray absorptiometry were used as a reference of the body composition. In terms of the results, regardless of the menopausal status, BIA slightly but significantly overestimated the percentage of body fat (standard error of estimate: 5.3%-6.7%) and the leg lean soft tissue mass (LSTM; 5.1%-6.1%), and underestimated the LSTM in the whole body (6.2%-7.6%) and arm (2.8%-3.7%). The absolute values of the predictive error for leg LSTM were significantly higher in postmenopausal groups than in the premenopausal ones. The corresponding values for the whole body and arm LSTM, and the percentage of body fat were higher in premenopausal groups than in postmenopausal ones. In conclusion, the predictive accuracy of BIA for postmenopausal women is not inferior to that for premenopausal ones, unless we target the leg LSTM. Copyright © 2015 The International Society for Clinical Densitometry. Published by Elsevier Inc. All rights reserved.

  1. Estimating body composition from skinfold thicknesses and bioelectrical impedance analysis in cystic fibrosis patients.

    Science.gov (United States)

    Alicandro, Gianfranco; Battezzati, Alberto; Bianchi, Maria Luisa; Loi, Silvana; Speziali, Chiara; Bisogno, Arianna; Colombo, Carla

    2015-11-01

    The accuracy of body composition estimates based on skinfold thickness measurements and bioelectrical impedance analysis (BIA) is not yet adequately explored in cystic fibrosis (CF). Using DXA as reference method we verified the accuracy of these techniques and identified predictors of body composition specific for CF. One hundred forty-two CF patients (age range: 8-31 years) underwent a DXA scan. Body fat percentage (BF%) was estimated from skinfolds, while fat free mass (FFM) from single-frequency 50 kHz BIA. Bland-Altman analysis showed poor intra-individual agreement between body composition data provided by DXA and BF% estimated from skinfolds or FFM estimated from BIA. The skinfolds of the upper arm were better predictors of BF% than BMI, while compared to other BIA measurements the best predictor of FFM was the R-index (Height(2)/Resistance). Due to poor accuracy at individual level, the estimates of body composition obtained from these techniques cannot be part of the standard nutritional assessment of CF patients until reliable CF-specific equations will become available. BMI has limited value in predicting body fatness in CF patients and should be used in combination with other predictors. Skinfolds of the upper arm and R-index are strongly related to BF% and FFM and should be tested in a large CF population to develop specific predictive equations. Copyright © 2015 European Cystic Fibrosis Society. Published by Elsevier B.V. All rights reserved.

  2. Comparison of Bioelectrical Impedance Analysis and Air Displacement Plethysmography in Community-Dwelling Older Adults.

    Science.gov (United States)

    Smale, K Brent; McIntosh, Emily I; Vallis, Lori Ann

    2016-05-01

    Clinicians and researchers use body composition measurements to identify individuals who may be at risk of adverse health complications. This study compared two commonly used two-compartmental anthropometric models (bioelectrical impedance analysis [BIA] and air displacement plethysmography [ADP]) to determine whether these two cost-effective methods would provide similar fat free mass index (FFMI) values in a mixed and sex-separated sample population of healthy older adults. Community-dwelling older adults (N= 37, 18 men) aged 74.5 ± 5.2 years participated. FFMIBIAwas correlated with FFMIADP(r= .916); however, these correlations were markedly reduced when the population was split by sex (r< .60). The level of agreement between the difference values (FFMIBIA- FFMIADP) fluctuated ± 2.1 kg/m(2)(illustrated via Bland-Altman plots), but these differences were not statistically different from 0. Findings from the current work suggest that clinicians must be cautious when using portable devices such as BIA to assess FFMI in an older adult population. © The Author(s) 2013.

  3. Bioelectrical impedance in young patients with cystic fibrosis: Validation of a specific equation and clinical relevance.

    Science.gov (United States)

    Charatsi, A M; Dusser, P; Freund, R; Maruani, G; Rossin, H; Boulier, A; Le Bourgeois, M; Chedevergne, F; de Blic, J; Letourneur, A; Casimir, G; Jais, J P; Sermet-Gaudelus, I

    2016-11-01

    Body composition (BC) analysis based on bioelectrical impedance analysis (BIA) provides conflicting results. The purpose of the study was to validate an equation specific for young patients with cystic fibrosis (CF), describe their BC and investigate its association with lung function. Fifty-four young CF patients were evaluated by BIA and dual X-ray absorptiometry (DXA). An empirically derived CF-specific equation for fat-free mass (FFM) estimation by BIA was elaborated after stepwise multivariate regression and the agreement between BIA and DXA was assessed by Bland-Altman plots. The association between BC and lung function was investigated by regression analysis. The mean difference between the BIA and DXA assessment was close to zero. A total of 22.5% of patients (n=9) presented a FFM z-score≤-2. They had a worse pulmonary function and diaphragmatic impairment. Among these 9 patients, 7 had a normal BMI z-score>-1. BIA, based on a CF-specific equation, is a reliable method for BC assessment and allows the identification of patients at risk of nutritional degradation and bad respiratory prognosis. Copyright © 2016 European Cystic Fibrosis Society. Published by Elsevier B.V. All rights reserved.

  4. Body composition by x-ray absorptiometry and bioelectrical impedance in female runners.

    Science.gov (United States)

    Pichard, C; Kyle, U G; Gremion, G; Gerbase, M; Slosman, D O

    1997-11-01

    Body composition interests athletes since athletic performance is influenced by and dependent on the proportion and total amount of fat-free mass (FFM) and fat mass. The use of bioelectrical impedance (BIA) has increased recently since portable instruments make the measurements easy to execute and relatively inexpensive. The purpose of this study was to test the degree of relationship between FFM and fat mass calculated in elite female runners with 12 different BIA formulas reported in the literature and measured by dual-energy x-ray absorptiometry (DXA). The present study shows that body composition by BIA is valid in female runners. Prediction equations used to calculate FFM and fat mass must be appropriate for this population subgroup and validated against other methods, such as DXA and hydrodensitometry. Those formulas that performed well in the controls gave poor results in the female runner and vice versa. The below average fat mass noted in female runners suggests that prediction equations for untrained women with average fat mass are inappropriate. The formula by RJL Systems-2 for women: FFM = 5.091 + 0.6483.height2/resistance + 0.1996.weight gave best predictions of FFM in female runners. Further research is necessary to validate BIA prediction formulas in other athletes.

  5. Comparison between two methods of bioelectrical impedance analyses for accuracy in measuring abdominal visceral fat area.

    Science.gov (United States)

    Park, Kyeong Seon; Lee, Dong-Hwa; Lee, JieEun; Kim, Yoon Ji; Jung, Kyong Yeun; Kim, Kyoung Min; Kwak, Soo Heon; Choi, Sung Hee; Park, Kyong Soo; Jang, Hak Chul; Lim, Soo

    2016-03-01

    To compare the accuracy of abdominal visceral fat area (VFA) measurements between abdominal dual bioelectrical impedance analysis (BIA) and whole-body BIA referenced to computed tomography (CT) measures. Abdominal VFAs were measured in 102 individuals: 59 men and 43 women with a mean age of 44.2 ± 16.3 years (range 21 - 76), body mass index 23.9 ± 7.8 kg/m(2) (range 18 - 35) using a DUALSCAN HDS-2000 machine (dual abdominal BIA) and an InBody720 machine (whole-body BIA). The VFA values from each machine were compared with those from CT under various conditions. Mean abdominal VFAs were 116 ± 69 cm(2) by CT, 89 ± 47 cm(2) by dual abdominal BIA, and 84 ± 33 cm(2) by whole-body BIA. The former measure showed a higher correlation with the CT measure than the latter (r=0.89 vs. r=0.64, P<0.001). Both BIA methods tended to underestimate abdominal VFAs compared with CT scans when CT VFA was not small. The dual abdominal BIA had less bias than the whole-body BIA in the assessment of VFAs. The whole-body BIA was affected by subcutaneous fat area. Dual BIA was more accurate in assessing abdominal VFA than whole-body BIA. Copyright © 2016 Elsevier Inc. All rights reserved.

  6. Combined evaluation of nutrition and hydration in dialysis patients with bioelectrical impedance vector analysis (BIVA).

    Science.gov (United States)

    Piccoli, Antonio; Codognotto, Marta; Piasentin, Paola; Naso, Agostino

    2014-08-01

    Body hydration changes continuously in hemodialysis patients. The Subjective Global Assessment (SGA) is used for the nutritional evaluation but it does not allow a direct evaluation of hydration. Bioelectrical impedance vector analysis (BIVA) is very sensitive to hydration. The potential of the combined evaluation of hydration and nutrition with SGA and BIVA is still lacking. Observational cross-sectional study on 130 (94 Male) uremic patients undergoing chronic hemodialysis three times a week. Nutritional status was evaluated with the SGA. Each subject was classified as SGA-A (normal nutritional status), SGA-B (moderate malnutrition), or SGA-C (severe malnutrition). Body hydration was evaluated with BIVA. The two vector components resistance (R) and reactance (Xc) were normalized by the subject's height and standardized as bivariate Z-score, i.e. Z(R) and Z(Xc). Undernutrition influenced impedance vector distribution both before and after a dialysis session. In pre-dialysis, the mean vector of SGA A was inside the 50% tolerance ellipse. In SGA B and C, Z(R) was increased and Z(Xc) decreased, indicating a progressive loss of soft tissue mass. Fluid removal with dialysis increased both Z(R) and Z(Xc) in SGA A and B but not in C. With ROC curve analysis on the slope of increase, we found the cutoff value of 27.8° below which undernutrition was present, either moderate or severe. The area under the ROC curve was 77.7° (95% CI 69.5-84.5, P hydration in each SGA category can be detected with BIVA. Copyright © 2013 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.

  7. Estimation of fat-free mass in Asian neonates using bioelectrical impedance analysis.

    Science.gov (United States)

    Tint, Mya-Thway; Ward, Leigh C; Soh, Shu E; Aris, Izzuddin M; Chinnadurai, Amutha; Saw, Seang Mei; Gluckman, Peter D; Godfrey, Keith M; Chong, Yap-Seng; Kramer, Michael S; Yap, Fabian; Lingwood, Barbara; Lee, Yung Seng

    2016-03-28

    The aims of this study were to develop and validate a prediction equation of fat-free mass (FFM) based on bioelectrical impedance analysis (BIA) and anthropometry using air-displacement plethysmography (ADP) as a reference in Asian neonates and to test the applicability of the prediction equations in an independent Western cohort. A total of 173 neonates at birth and 140 at two weeks of age were included. Multiple linear regression analysis was performed to develop the prediction equations in a two-third randomly selected subset and validated on the remaining one-third subset at each time point and in an independent Queensland cohort. FFM measured by ADP was the dependent variable, and anthropometric measures, sex and impedance quotient (L2/R50) were independent variables in the model. Accuracy of prediction equations was assessed using intra-class correlation and Bland-Altman analyses. L2/R50 was the significant predictor of FFM at week two but not at birth. Compared with the model using weight, sex and length, including L2/R50 slightly improved the prediction with a bias of 0·01 kg with 2 sd limits of agreement (LOA) (0·18, -0·20). Prediction explained 88·9 % of variation but not beyond that of anthropometry. Applying these equations to the Queensland cohort provided similar performance at the appropriate age. However, when the Queensland equations were applied to our cohort, the bias increased slightly but with similar LOA. BIA appears to have limited use in predicting FFM in the first few weeks of life compared with simple anthropometry in Asian populations. There is a need for population- and age-appropriate FFM prediction equations.

  8. The diagnostic accuracy of multi-frequency bioelectrical impedance analysis in diagnosing dehydration after stroke

    Science.gov (United States)

    Kafri, Mohannad W.; Myint, Phyo Kyaw; Doherty, Danielle; Wilson, Alexander Hugh; Potter, John F.; Hooper, Lee

    2013-01-01

    Background Non-invasive methods for detecting water-loss dehydration following acute stroke would be clinically useful. We evaluated the diagnostic accuracy of multi-frequency bioelectrical impedance analysis (MF-BIA) against reference standards serum osmolality and osmolarity. Material/Methods Patients admitted to an acute stroke unit were recruited. Blood samples for electrolytes and osmolality were taken within 20 minutes of MF-BIA. Total body water (TBW%), intracellular (ICW%) and extracellular water (ECW%), as percentages of total body weight, were calculated by MF-BIA equipment and from impedance measures using published equations for older people. These were compared to hydration status (based on serum osmolality and calculated osmolarity). The most promising Receiver Operating Characteristics curves were plotted. Results 27 stroke patients were recruited (mean age 71.3, SD10.7). Only a TBW% cut-off at 46% was consistent with current dehydration (serum osmolality >300 mOsm/kg) and TBW% at 47% impending dehydration (calculated osmolarity ≥295–300 mOsm/L) with sensitivity and specificity both >60%. Even here diagnostic accuracy of MF-BIA was poor, a third of those with dehydration were wrongly classified as hydrated and a third classified as dehydrated were well hydrated. Secondary analyses assessing diagnostic accuracy of TBW% for men and women separately, and using TBW as a percentage of lean body mass showed some promise, but did not provide diagnostically accurate measures across the population. Conclusions MF-BIA appears ineffective at diagnosing water-loss dehydration after stroke and cannot be recommended as a test for dehydration, but separating assessment by sex, and using TBW as a percentage of lean body weight may warrant further investigation. PMID:23839255

  9. Effect of anti IL-12/23 on body composition: results of bioelectrical impedance analysis in Caucasian psoriatic patients.

    Science.gov (United States)

    Galluzzo, Marco; D'Adamio, Simone; Pastorino, Roberta; Andreoli, Angela; Servoli, Stella; Bianchi, Luca; Talamonti, Marina

    2018-03-01

    Bioelectrical impedance analysis (BIA) is an inexpensive, non-invasive and fast method to assess body composition. Little is known of the interaction between anti IL 12/23 treatment and body composition. The aim of this study was to evaluate 6- and 12-month changes in body weight, Body Mass Index (BMI) and body composition assessed by BIA in psoriatic patients treated with anti-IL-12/23. Demographic and clinical data were collected for each enrolled patient. Physical examination, anthropometric assessment, Psoriasis Area and Severity Index (PASI) assessment and body composition by BIA (single-frequency 50 kHz), were assessed at baseline and at 6 and 12 months of treatment. A significant decrease in body weight, compared to baseline, in BMI, Fat Mass at month 6 and a significant increase at month 12 for body cellular mass (BCM) and Phase Angle (PhA) were observed. In addition, a significant increase was found for intracellular water. At baseline, psoriatic patients showed a lower BCM and a lower mean PhA score. During ustekinumab treatment, the mean PhA and BCM scores increased with an improvement in psoriatic disease. Thus, ustekinumab can be an effective drug for improving not only psoriasis but also the general clinical status of patients.

  10. Electrical Properties Assessed by Bioelectrical Impedance Spectroscopy as Biomarkers of Age-related Loss of Skeletal Muscle Quantity and Quality.

    Science.gov (United States)

    Yamada, Yosuke; Buehring, Bjoern; Krueger, Diane; Anderson, Rozalyn M; Schoeller, Dale A; Binkley, Neil

    2017-09-01

    Skeletal muscle, in addition to being comprised of a heterogeneous muscle fiber population, also includes extracellular components that do not contribute to positive tensional force production. Here we test segmental bioelectrical impedance spectroscopy (S-BIS) to assess muscle intracellular mass and composition. S-BIS can evaluate electrical properties that may be related to muscle force production. Muscle fiber membranes separate the intracellular components from the extracellular environment and consist of lipid bilayers which act as an electrical capacitor. We found that S-BIS measures accounted for ~85% of the age-related decrease in appendicular muscle power compared with only ~49% for dual-energy x-ray absorptiometry (DXA) measures. Indices of extracellular (noncontractile) and cellular (contractile) compartments in skeletal muscle tissues were determined using the Cole-Cole plot from S-BIS measures. Characteristic frequency, membrane capacitance, and phase angle determined by Cole-Cole analysis together presented a S-BIS complex model that explained ~79% of interindividual variance of leg muscle power. This finding underscores the value of S-BIS to measure muscle composition rather than lean mass as measured by DXA and suggests that S-BIS should be highly informative in skeletal muscle physiology. © The Author 2016. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  11. Predicting body composition using foot-to-foot bioelectrical impedance analysis in healthy Asian individuals.

    Science.gov (United States)

    Wu, Chun-Shien; Chen, Yu-Yawn; Chuang, Chih-Lin; Chiang, Li-Ming; Dwyer, Gregory B; Hsu, Ying-Lin; Huang, Ai-Chun; Lai, Chung-Liang; Hsieh, Kuen-Chang

    2015-05-19

    The objectives of this study were to develop a regression model for predicting fat-free mass (FFM) in a population of healthy Taiwanese individuals using standing foot-to-foot bioelectrical impedance analysis (BIA) and to test the model's performance in predicting FFM with different body fat percentages (BF%). We used dual-energy X-ray absorptiometry (DXA) to measure the FFM of 554 healthy Asian subjects (age, 16-75 y; body mass index, 15.8-43.1 kg/m(2)). We also evaluated the validity of the developed multivariate model using a double cross-validation technique and assessed the accuracy of the model in an all-subjects sample and subgroup samples with different body fat levels. Predictors in the all-subjects multivariate model included height(2)/impedance, weight, year, and sex (FFM = 13.055 + 0.204 weight + 0.394 height(2)/Impedance - 0.136 age + 8.125 sex (sex: Female = 0, Male = 1), r(2) = 0.92, standard error of the estimate = 3.17 kg). The correlation coefficients between predictive FFM by BIA (FFMBIA) and DXA-measured FFM (FFMDXA) in female subjects with a total-subjects BF%DXA of 40 % were r = 0.87, 0.90, 0.91, 0.89, and 0.94, respectively, with bias ± 2SD of 0.0 ± 3.0 kg, -2.6 ± 1.7 kg, -1.5 ± 2.8 kg, 0.5 ± 2.7 kg, and 2.0 ± 2.9 kg, respectively. The correlation coefficients between FFMBIA and FFMDXA in male subjects with a total-subjects BF%DXA of 30 % were r = 0.89, 0.89, 0.90, 0.93, and 0.91, respectively, with bias ± 2SD of 0.0 ± 3.2 kg, -2.3 ± 2.5 kg, -0.5 ± 3.2 kg, 0.4 ± 3.1 kg, and 2.1 ± 3.2 kg, respectively. The standing foot-to-foot BIA method developed in this study can accurately predict FFM in healthy Asian individuals with different levels of body fat.

  12. Early detection of subclinical edema in chronic kidney disease patients by bioelectrical impedance analysis.

    Science.gov (United States)

    Thanakitcharu, Prasert; Jirajan, Boonthum

    2014-11-01

    Abnormalities in body water distribution are common in chronic kidney disease (CKD) patients. Volume expansion, even in the absence of overt edema, contributes to high blood pressure, and progressive volume expansion eventually leads to clinical edema and fluid overload. Total body water (TBW) can be accurately estimated by multifrequency bioelectrical impedance analysis (MF-BIA) which has been proposed for earlier detection of subclinical edema in CKD patients. To study body fluid distribution and edematous states in CKD patients measured by MF-BIA, compared with clinical edema assessed by physical examination. In addition, to evaluate the correlation of MF-BIA estimated TBW and anthropometry-derived TBW calculated by Watson formula. CKD patients at Rajavithi Hospital together with healthy adults were prospectively enrolled during a 12-month period. The body fluid compositions assessed by bioelectrical impedance analyzer (InBody® S20, Republic of Korea) were taken immediately after physical examination for edema detection. The patients were categorized into stages 1 to 5 according to CKD staging in the NKF-K/DOQI guidelines, and reclassified into 3 groups of stages l-2, stages 3-4, and stage 5. Sixty-nine CKD patients were compared with 48 healthy volunteers. The estimated glomerular filtration rate (GFR) in CKD patients and normal controls were 53.5±41.1 and 113.9±0.8 ml/min/1.73 m2 respectively. The extracellular water (ECW) to TBW ratio, which represents edematous state if higher than 0.4, was significantly higher in patients with CKD stages 3-4 (0.400±0.008) and stage 5 (0.404±0.011), than in those in CKD stages 1-2 (0.393±0.009) and controls (0.385±0.007) (p<0.001). The prevalence of edematous state detected by BIA (edema-BIA) in CKD patients was significantly greater than in normal controls (78.3% vs. 25.0%, p<0.001). The number of CKD patients with edema-BIA was also significantly higher than the number of patients with clinical edema (36.2%), which

  13. Cross-validation of bioelectrical impedance analysis of body composition in children and adolescents.

    Science.gov (United States)

    Wu, Y T; Nielsen, D H; Cassady, S L; Cook, J S; Janz, K F; Hansen, J R

    1993-05-01

    The reliability and validity of measurements obtained with two bioelectrical impedance analyzers (BIAs), an RJL Systems model BIA-103 and a Berkeley Medical Research BMR-2000, were investigated using the manufacturers' prediction equations for the assessment of fat-free mass (FFM) (in kilograms) in children and adolescents. Forty-seven healthy children and adolescents (23 male, 24 female), ranging in age from 8 to 20 years (mean = 12.1, SD = 2.3), participated. In the context of a repeated-measures design, the data were analyzed according to gender and maturation (Tanner staging). Hydrostatic weighing (HYDRO) and Lohman's Siri age-adjusted body density prediction equation served as the criteria for validating the BIA-obtained measurements. High intraclass correlation coefficients (ICC > or = .987) demonstrated good test-retest (between-week) measurement reliability for HYDRO and both BIA methods. Between-method (HYDRO versus BIA) correlation coefficients were high for both boys and girls (r > or = .97). The standard errors of estimate (SEEs) for FFM were slightly larger for boys than for girls and were consistently smaller for the RJL system than for the BMR system (RJL SEE = 1.8 kg for boys, 1.3 kg for girls; BMR SEE = 2.4 kg for boys, 1.9 kg for girls). The coefficients of determination were high for both BIA methods (r2 > or = .929). Total prediction errors (TEs) for FFM showed similar between-method trends (RJL TE = 2.1 kg for boys, 1.5 kg for girls; BMR TE = 4.4 kg for boys, 1.9 kg for girls). This study demonstrated that the RJL BIA with the manufacturer's prediction equations can be used to reliably and accurately assess FFM in 8- to 20-year-old children and adolescents. The prediction of FFM by the BMR system was acceptable for girls, but significant overprediction of FFM for boys was noted.

  14. Assessment of body composition using bioelectrical impedance analysis in Prader-Willi syndrome

    Directory of Open Access Journals (Sweden)

    Hsiang-Yu Lin

    2011-11-01

    Full Text Available This study investigated the use of bioelectrical impedance analysis (BIA as a means of assessing body composition in patients with Prader-Willi syndrome (PWS. Segmental, multifrequency BIA was performed on 30 patients with PWS (16 males and 14 females; mean age: 8.1 ± 3.9 years; age range: 2.9–19.6 years using eight tactile electrodes. No patient had received growth hormone treatment prior to baseline measurements. Standard deviation scores for height, weight, and body mass index were –0.96 ± 1.29, 2.28 ± 2.66, and 3.14 ± 2.74, respectively. Percentages of body fat, total body water, and soft lean mass were 45.9 ± 10.8%, 36.6 ± 7.3%, and 49.9 ± 9.9%, respectively. Body fat percentage was positively correlated with the body mass index standard deviation score (r = 0.665, p < 0.01. Follow-up BIA was also performed on five patients who received growth hormone therapy (duration of treatment: 1.5–4.6 years. All of these patients showed reductions in their body fat percentages after treatment. BIA confirmed a significantly higher percentage of body fat in patients with PWS compared with normal children. These findings and the follow-up data can be used to develop quality care strategies for patients with PWS.

  15. Validating Body Fat Assessment by Bioelectric Impedance Spectroscopy in Taiwanese Hemodialysis Patients.

    Science.gov (United States)

    Lim, Paik Seong; Chen, Chang Hsu; Zhu, Fansan; Kotanko, Peter; Jeng, Yachung; Hu, Chun Yu; Chiu, Li Shu; Chang, Hui-Chen

    2017-01-01

    Obesity is becoming increasingly common in hemodialysis (HD) patients and is associated with inflammation and increased mortality. The primary aim of the present study was to evaluate the accuracy and variability of the bioimpedance device in measuring body fat in Taiwanese dialysis patients. Cross-sectional study. One hundred twenty-two adult patients receiving HD in a single hospital in Taiwan. We compared the results of fat mass (FM) measured by dual-energy x-ray absorptiometry (DEXA) and bioelectrical impedance spectroscopy device (Body composition monitor, BCM). FM measured by BCM was calculated by subtracting fat-free mass (FFM) from body mass assuming fractional hydration of FFM of 0.73 or the proprietary prediction equations from the BCM model. Assessment of whole-body composition showed that percentage FM measured using the 2 techniques was highly correlated when using the BCM model or estimating from total body water using constant (0.73) hydration (r = 0.87, P < .001). There was no evident difference in measurement between patients gender. The Bland-Altman plot also showed good agreement of percentage of FM (t = 3.82; P < .001). In female patients, it was found that BCM significantly underestimated mean FM as compared to DEXA. However, the mean differences of the estimates between the methods were small (0.35 ± 3.00 kg) and with Bland-Altman plot the limits of agreements were -5.5 to 6.2 kg (P = .40) for FM in female patients. Using DEXA as the reference test, BCM is a valid tool for the assessment of total body fat in HD patients. Hence, it may provide a more accessible tool for early detection of changes in body composition in these high-risk patients. Copyright © 2016 National Kidney Foundation, Inc. Published by Elsevier Inc. All rights reserved.

  16. Body composition by underwater weighing and bioelectrical impedance methods in college students

    Directory of Open Access Journals (Sweden)

    Cândido S. Pires Neto

    1999-12-01

    Full Text Available The objective of this study was to determine and to compare % fat, LBM and FM of male and female college students measured by hydrostatic weighing and bioelectrical impedance assessment (BIA. To this end, 115 subjects (57 male and 58 female, aged 18 to 30, were assessed by BIA and hydrostatic weighing, which was adopted as the gold standard. The t test for dependent samples revealed that there was a statistically signifi cant difference (p RESUMO objetivo desse estudo foi determinar e comparar o percentual de gordura, massa corporal magra (MCM e massa gorda (MG obtidos pelos métodos da pesagem hidrostática e impedância bioelétrica em universitários dos sexos masculino e feminino. Para tanto, foram avaliados 115 sujeitos (57 homens e 58 mulheres entre 18 e 30 anos de idade através da impedância bioelétrica (IB e pesagem hidrostática (PH, que foi o método adotado como critério. O teste t para amostras dependentes revelou que houve diferença estatística significante, p < 0,001, entre os valores médios das variáveis da composição corporal, apesar da correlação de Pearson entre o %G, MG e MCM decorrente dos dois métodos, terem sido significantes, p < 0,001. Concluímos que a utilização da IB como recurso para as estimativas dos componentes da composição corporal sugere extrema cautela na interpretação dos mesmos.

  17. Bioelectrical impedance as a measure of change in body composition in young children.

    Science.gov (United States)

    Meredith-Jones, K A; Williams, S M; Taylor, R W

    2015-08-01

    The ability of bioelectrical impedance (BIA) to measure change in body composition in children has rarely been examined. Body composition was estimated by BIA (Tanita BC-418) and dual-energy x-ray absorptiometry (DXA) in 187 children aged 4-8 years at baseline and at 12 months. Change in body composition was compared between the two methods using mixed models. Estimates of change in fat mass did not differ between BIA and DXA for overweight girls (mean difference between methods, 95% confidence interval: 0.04 kg, -0.19 to 0.28) or boys (0.07 kg, -0.14 to 0.27). BIA was also able to accurately detect change in fat-free mass, with no significant differences between methods (-0.14 kg, -0.10 to 0.38 in girls and -0.07 kg, -0.35 to -0.20 in boys). Change in percentage fat produced similar estimates in both genders (0.18%, -0.82 to 0.46 in girls and 0.38%, -0.37 to 1.13 in boys). BIA/DXA comparisons in normal weight children were also not significantly different, with the exception of percentage fat in girls, where BIA slightly underestimated change compared with DXA (0.7%, 0.02-0.37). BIA performed well as a measure of change in body composition, providing confidence for its use as an outcome measure in children. © 2014 World Obesity.

  18. Total body fat and the risk of Barrett's oesophagus – a bioelectrical impedance study

    Science.gov (United States)

    Kendall, Bradley J; Macdonald, Graeme A; Prins, Johannes B; O'Brien, Suzanne; Whiteman, David C

    2014-01-01

    Background Body mass index is associated with the risk of Barrett's oesophagus (BO). It is uncertain whether this is related to total body fat or other factors that correlate with body mass index. We aimed to quantify the association between total body fat (measured by bioelectrical impedance) and risk of BO and examine if this association was modified by gastro-oesophageal reflux (GOR) and abdominal obesity. Methods In 2007-9, we surveyed 235 cases (69% Males, Mean age 62.1 years) and 244 age and sex matched population controls from a population based case-control study of BO. We conducted structured interviews, standard anthropometry and bioimpedance analysis of total body fat. Odds ratios (OR) and 95% confidence intervals (CI) were estimated using multivariable logistic regression analysis. Results There was a significantly increased risk of BO among those in the highest tertile of total body fat weight (OR 2.01; 95%CI 1.26-3.21) and total body fat percentage (OR 1.86; 95%CI 1.10-3.15). These risks were largely attenuated after adjustment for GOR and waist circumference. There was a significantly increased risk of BO among those in the highest tertile of waist circumference (OR 2.21; 95%CI 1.39-3.51) and this was minimally attenuated after adjustment for total body fat and moderately attenuated after adjustment for GOR. Conclusions Total body fat is associated with an increased risk of BO but this appears to be mediated via both abdominal obesity and GOR. These findings provide evidence that abdominal obesity is more important than total body fat in the development of BO. PMID:24726825

  19. Performance of bioelectrical impedance analysis in the diagnosis of metabolic syndrome.

    Science.gov (United States)

    Ozhan, Hakan; Alemdar, Recai; Caglar, Onur; Ordu, Serkan; Kaya, Ahmet; Albayrak, Sinan; Turker, Yasin; Bulur, Serkan

    2012-03-01

    Central obesity is a prerequisite for the diagnosis of metabolic syndrome (MetS). Precise measurement of visceral fat by bioelectrical impedance analysis (BIA) has been validated. The aim of this study was to investigate the diagnostic performance of BIA in MetS and validate the best cutoff in a large adult cohort. The study was performed on the MELEN Study cohort-a prospectively designed survey on the prevalence of cardiometabolic risk factors in Turkish adults. The final cohort consisted of 2219 participants. Weight and visceral body composition were measured without shoes in light indoor clothes using a bioimpedance analyzer (Omron BF 510; Omron Corp, Kyoto, Japan). Plasma concentrations of cholesterol, insulin, fasting triglycerides, high-density lipoprotein cholesterol, glucose, and other biochemical variables were measured. The diagnostic performance of visceral fat measurement by BIA in patients with MetS was assessed. Metabolic syndrome was detected in 751 participants (520 women and 231 men with a mean age of 55 [12] years; 34% of the whole study population). Total body fat and visceral fat levels were higher in subjects with MetS. Correlation analyses showed that there were significant correlations between anthropometric and BIA measurements. Receiver operating curve characteristics of visceral adiposity revealed the best cutoff values as greater than 12% for men and greater than 9% for women. The diagnostic performance was good in both sexes (the sensitivity/specificity and area-under-the-curve values were 76%/75% and 0.83 for men and 83%/67% and 0.81 for women, respectively). Visceral fat measured with BIA is an easily applicable and useful method for identifying people with MetS. The best cutoff values were higher than 12% for men and higher than 9% for women.

  20. Total body fat and the risk of Barrett's oesophagus - a bioelectrical impedance study.

    Science.gov (United States)

    Kendall, Bradley J; Macdonald, Graeme A; Prins, Johannes B; O'Brien, Suzanne; Whiteman, David C

    2014-06-01

    Body mass index is associated with the risk of Barrett's oesophagus (BO). It is uncertain whether this is related to total body fat or other factors that correlate with body mass index. We aimed to quantify the association between total body fat (measured by bioelectrical impedance) and risk of BO and examine if this association was modified by gastro-oesophageal reflux (GOR) and abdominal obesity. In 2007-2009, we surveyed 235 cases (69% Males, Mean age 62.1 years) and 244 age and sex matched population controls from a population based case-control study of BO. We conducted structured interviews, standard anthropometry and bioimpedance analysis of total body fat. Odds ratios (OR) and 95% confidence intervals (CI) were estimated using multivariable logistic regression analysis. There was a significantly increased risk of BO among those in the highest tertile of total body fat weight (OR 2.01; 95%CI 1.26-3.21) and total body fat percentage (OR 1.86; 95%CI 1.10-3.15). These risks were largely attenuated after adjustment for GOR and waist circumference. There was a significantly increased risk of BO among those in the highest tertile of waist circumference (OR 2.21; 95%CI 1.39-3.51) and this was minimally attenuated after adjustment for total body fat and moderately attenuated after adjustment for GOR. Total body fat is associated with an increased risk of BO but this appears to be mediated via both abdominal obesity and GOR. These findings provide evidence that abdominal obesity is more important than total body fat in the development of BO. Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. Validity of leg-to-leg bioelectrical impedance analysis to estimate body fat in obesity.

    Science.gov (United States)

    Lloret Linares, Célia; Ciangura, Cécile; Bouillot, Jean-Luc; Coupaye, Muriel; Declèves, Xavier; Poitou, Christine; Basdevant, Arnaud; Oppert, Jean-Michel

    2011-07-01

    Bioelectrical impedance analysis (BIA) is a safe and easy method of assessing body composition. Its accuracy to predict fat mass (FM) in obesity and the change in FM following weight loss is questioned. Our objective was to compare leg-to-leg BIA to dual-energy X-ray absorptiometry (DXA) in the assessment of FM in a large population, the changes in FM after Roux-en-Y gastric bypass (RYGB) and to estimate between-method differences (bias) and limits of agreement. BIA (Tanita BC-420MA) and DXA (Hologic Discovery W) were used in 5,740 consecutive patients (mean BMI, 37.7 ± 8.2 kg/m(2)) examined in a clinical nutrition department and in 72 women undergoing RYGB (BMI, 47.2 ± 7.2 kg/m(2)). Analyses included correlations between methods and Bland Altman analysis. In the entire population, BIA significantly overestimated FM in comparison with DXA (1.1 ± 6.1 kg, 0.8 ± 5.6%). FM estimates by each method were significantly correlated in absolute value (kg; r(2) = 0.9 in the whole population), and in percentage (r(2) = 0.6). However, wide limits of agreement were observed. In surgery patients, BIA significantly overestimated FM both before and 12 months after bypass. BIA significantly overestimated changes in FM after RYGB at 3 months (2.9 ± 5.0 kg) and at 12 months (1.9 ± 3.9 kg) but not at 6 months (0.9 ± 5.0 kg; p = 0.08). Estimates of changes in FM by each method were significantly correlated (r (2) = 0.4, 0.6, and 0.9, respectively). According to the wide limits of agreement, BIA seems more interesting for epidemiological rather than individual use to evaluate body FM and FM changes in obese women undergoing RYGB.

  2. Body composition measures of obese adolescents by the deuterium oxide dilution method and by bioelectrical impedance

    Directory of Open Access Journals (Sweden)

    C.M.M. Resende

    2011-11-01

    Full Text Available The objectives of the present study were to describe and compare the body composition variables determined by bioelectrical impedance (BIA and the deuterium dilution method (DDM, to identify possible correlations and agreement between the two methods, and to construct a linear regression model including anthropometric measures. Obese adolescents were evaluated by anthropometric measures, and body composition was assessed by BIA and DDM. Forty obese adolescents were included in the study. Comparison of the mean values for the following variables: fat body mass (FM; kg, fat-free mass (FFM; kg, and total body water (TBW; % determined by DDM and by BIA revealed significant differences. BIA overestimated FFM and TBW and underestimated FM. When compared with data provided by DDM, the BIA data presented a significant correlation with FFM (r = 0.89; P < 0.001, FM (r = 0.93; P < 0.001 and TBW (r = 0.62; P < 0.001. The Bland-Altman plot showed no agreement for FFM, FM or TBW between data provided by BIA and DDM. The linear regression models proposed in our study with respect to FFM, FM, and TBW were well adjusted. FFM obtained by DDM = 0.842 x FFM obtained by BIA. FM obtained by DDM = 0.855 x FM obtained by BIA + 0.152 x weight (kg. TBW obtained by DDM = 0.813 x TBW obtained by BIA. The body composition results of obese adolescents determined by DDM can be predicted by using the measures provided by BIA through a regression equation.

  3. Bioelectrical impedance vector analysis in obese women before and after bariatric surgery: changes in body composition.

    Science.gov (United States)

    Nicoletti, Carolina Ferreira; Camelo, José Simon; dos Santos, José Ernesto; Marchini, Julio Sergio; Salgado, Wilson; Nonino, Carla Barbosa

    2014-05-01

    Because of the inefficacy of standard methods for the evaluation of body composition of grade III obese individuals, it is difficult to analyze the quality of weight loss after bariatric surgery in these patients. Electrical bioimpedance vector analysis and the RXc graph uses crude resistance (R) and reactance (Xc) values, like components of the Z vector, to monitor variations in body fluid and the nutritional status of obese individuals. Using bioelectrical impedance vector analysis (BIVA) and the RXc graph, the objective of the present study was to evaluate long-term changes in weight and body composition of obese women after Roux-en-Y bariatric surgery. A study was conducted on 43 grade III obese women submitted to bariatric surgery. Anthropometric and bioimpedance (800 mA-50 kHz) data were obtained during the preoperative period and 1, 2, 3, and 4 y after surgery. BIVA was performed by plotting resistance and reactance values corrected for body height (R/H and Xc/H, Ohm/m) as bivariates on the RXc graph. BIVA software was used to plot the vectors of the RXc plane. Surgery promoted changes in body composition, with a reduction of fat mass and of fat-free mass. During the postoperative period, the vectors demonstrated migration to the right lower quadrant of the graph, corresponding to the classification of cachexia and water retention. Weight loss due to surgery results in an important reduction of fat-free mass characterized by the position of most individuals in the cachexia quadrant throughout the postoperative period. Copyright © 2014 Elsevier Inc. All rights reserved.

  4. Fat mass by bioelectrical impedance analysis is not associated with increased risk of Barrett esophagus.

    Science.gov (United States)

    Thrift, Aaron P; Kramer, Jennifer R; Alsarraj, Abeer; El-Serag, Hashem B

    2014-03-01

    To evaluate whether the association between obesity and Barrett esophagus (BE) is due to total body fatness, abdominal obesity, or both. BE risk seems to be more strongly related to central obesity than total obesity. However, no studies have investigated the association between total obesity and BE using direct measures of total body fatness. We conducted a case-control study among patients scheduled for elective esophagogastroduodenoscopy, and a sample of patients eligible for screening colonoscopy recruited from primary care clinics. BE cases were patients with specialized intestinal metaplasia, whereas controls had no endoscopic or histopathologic BE. All patients underwent a study esophagogastroduodenoscopy and had body measurements taken. Fat mass and fat-free mass were estimated from bioelectrical impedance analysis (BIA). We calculated odds ratios (OR) and 95% confidence intervals (95% CI) using multivariable logistic regression. There were 70 BE cases, 229 endoscopy controls, and 118 primary care controls. BMI and BIA-derived fat mass were highly correlated; however, we found no association between BMI, fat mass, and BE (vs. all controls: BMI, OR/1 SD=1.01; 95% CI, 0.76-1.34; fat mass, OR=1.02; 95% CI, 0.77-1.36). Waist-to-hip ratio was significantly associated with increased BE risk (vs. all controls: OR/1 SD=1.45; 95% CI, 1.03-2.04). We found similar results when we analyzed the control groups separately. Waist-to-hip ratio, but not fat mass or BMI, was associated with increased BE risk. This study provides strong evidence that BE is related to body size and composition through central adiposity and not through total body fatness.

  5. Fat mass by bioelectrical impedance analysis is not associated with increased risk of Barrett's esophagus

    Science.gov (United States)

    Thrift, Aaron P.; Kramer, Jennifer R.; Alsarraj, Abeer; El-Serag, Hashem B.

    2013-01-01

    Goal To evaluate whether the association between obesity and Barrett's esophagus (BE) is due to total body fatness, abdominal obesity, or both. Background BE risk appears more strongly related to central obesity than total obesity. However, no studies have investigated the association between total obesity and BE using direct measures of total body fatness. Study We conducted a case-control study among patients scheduled for elective esophagogastroduodenoscopy (EGD), and a sample of patients eligible for screening colonoscopy recruited from primary care clinics. BE cases were patients with specialized intestinal metaplasia; while controls had no endoscopic or histopathologic BE. All patients underwent a study EGD and had body measurements taken. Fat mass and fat-free mass were estimated from bioelectrical impedance analysis (BIA). We calculated odds ratios (OR) and 95% confidence intervals (95%CI) using multivariable logistic regression. Results There were 70 BO cases, 229 endoscopy controls and 118 primary care controls. BMI and BIA derived fat mass were highly correlated; however we found no association between BMI, fat mass and BE (vs. all controls: BMI, OR per 1 standard deviation [s.d.] = 1.01, 95%CI 0.76–1.34; fat mass, OR=1.02, 95%CI 0.77–1.36). WHR was significantly associated with increased BE risk (vs. all controls: OR=1.45, 95%CI 1.03–2.04). We found similar results when we analyzed the control groups separately. Conclusion WHR, but not fat mass or BMI, was associated with increased BE risk. This study provides strong evidence that BE is related to body size and composition via central adiposity and not via total body fatness. PMID:23842216

  6. Monitoring Volume Status Using Bioelectrical Impedance Analysis in Chronic Hemodialysis Patients.

    Science.gov (United States)

    Kim, Chae Rim; Shin, Jung-Ho; Hwang, Jin Ho; Kim, Su Hyun

    Fluid overload can be an independent risk factor of cardiovascular events and all-cause death in end-stage renal disease (ESRD) patients on chronic hemodialysis. We performed a retrospective study to investigate whether intermittent control of fluid status decreases the rate of these complications using bioelectrical impedance analysis (BIA). In ESRD patients on chronic hemodialysis, we identified the ratio of extracellular water to total body water (ECW/TBW) every 6 months using InBody S10 (Biospace, Seoul, Korea), which was measured within 30 minutes after dialysis initiation on the first dialysis day of the week. The uncontrolled group included 57 (40.1%) patients with all ECW/TBW measurements ≥0.40; in contrast, the controlled group included 85 (59.9%) with any measured ECW/TBW <0.40. Included patients were followed for 29 (12-42) months. The risk of cardiovascular events was higher in the uncontrolled group (hazard ratio [HR], 2.4; 95% confidence interval [CI], 1.2-5.1; p < 0.05) than it was in the controlled group; however, this difference disappeared after adjusting for age, sex, and Charlson comorbidity index (not significant). On the other hand, the patients in the uncontrolled group had a higher risk of all-cause death than did those in the controlled group, independent of age, sex, and Charlson comorbidity index (HR, 4.7; 95% CI, 1.4-16.1; p < 0.05). In conclusion, monitoring volume status using BIA may help to predict all-cause death in chronic hemodialysis patients. Further controlled studies are needed to confirm that strict volume control could reduce the rates of cardiovascular events and mortality in this population.

  7. Efficacy of bioelectrical impedance analysis during the perioperative period in children.

    Science.gov (United States)

    Song, In-Kyung; Kim, Dong-Ho; Kim, Eun-Hee; Lee, Ji-Hyun; Kim, Jin-Tae; Kim, Hee-Soo

    2017-06-01

    We evaluated the efficacy of bioelectrical impedance analysis (BIA) during the perioperative period by estimating the preoperative and postoperative body fluid status. After obtaining informed consent, we enrolled 100 children (3-12 years of age) scheduled for elective surgeries. All children had been fasted preoperatively. The children's body fluid status was estimated using a BIA machine (InBody S10; Biospace, Korea) in the ward on the afternoon before surgery (baseline), just before surgery and immediately after surgery. The total administered fluid volume during the fasting period, total administered fluid volume during the operation and fasting time were recorded. Continuous data are shown as mean ± standard deviation, and Pearson's correlation analysis was used to assess relationships between the preoperative fluid deficit and intracellular water (ICW)/extracellular water (ECW) changes. The mean fasting period was 13.3 h (range 5.8-19.7 h). A weak positive correlation was shown between the ICW and fluid deficit during the fasting period (Pearson correlation coefficient = 0.254; P = 0.010). A stronger positive correlation was shown between the ECW and fluid deficit during the fasting period (Pearson correlation coefficient = 0.359; P < 0.001). The baseline and postoperative ICW showed a strong positive correlation (Pearson correlation coefficient = 0.992, P < 0.001), as did the baseline and postoperative ECW (Pearson correlation coefficient = 0.990, P < 0.001). Also there was no dehydration and irritability on medical recording preoperatively. BIA may be an alternative method for estimating the perioperative fluid status in children and determining details of fluid administration.

  8. Comparison of body fat using various bioelectrical impedance analyzers in university students

    Directory of Open Access Journals (Sweden)

    Petr Kutáč

    2015-12-01

    Full Text Available Background: At present, the portfolio of devices using the bioelectrical impedance (BIA method is continuously expanding as a result of the wide use of this method in the field as measurements by this method are fast and staff training is simple and reasonably priced. Nonetheless, the problem is that despite using the same method, bioimpedance analyzers can differ in many parameters. They use different electric current frequencies, a different number of electrodes and the electric current may be conducted through different parts of the body.Objective: The main objective of the study is to compare and evaluate the differences of values of the analysis of the body fat of university students measured by BIA analyzers that differ in the applied electric current frequency, number of electrodes and flow of the electric current through the individual body parts.Methods: The research included 125 participants (70 male and 55 female. The measurements were taken by the following analyzers: Tanita 418 MA, InBody 720, InBody R20 and Omron BF 300.Results: The differences in the mean values of the body fat representation between the used analyzers in men ranged from 0.1 to 3.4% and from 0.0 to 2.4 kg, in women from 0.5 to 6.5% and from 0.4 to 3.8 kg in relation to the used analyzer.Conclusions: In men with regular physical activity, the values measured by InBody R20 were statistically and practically different. The analyzer measured higher values that other analyzers. In women, there were statistically and practically significant differences in the values measured by Omron BF 300. This analyzer measured lower values than other analyzers.

  9. Phase angle as bioelectrical marker to identify elderly patients at risk of sarcopenia.

    Science.gov (United States)

    Basile, Claudia; Della-Morte, David; Cacciatore, Francesco; Gargiulo, Gaetano; Galizia, Gianluigi; Roselli, Mario; Curcio, Francesco; Bonaduce, Domenico; Abete, Pasquale

    2014-10-01

    Several markers have been associated with sarcopenia in the elderly, including bioelectrical indices. Phase angle (PhA) is an impedance parameter and it has been suggested as an indicator of cellular death. Thus, the relationship between PhA and muscle mass and strength was investigated in 207 consecutively elderly participants (mean age 76.2±6.7years) admitted for multidimensional geriatric evaluation. Muscle strength by grip strength using a hand-held dynamometer and muscle mass was measured by bioimpedentiometer. PhA was calculated directly with its arctangent (resistance/reactance×180°/π). Linear relationship among muscular mass and strength and with clinical and biochemical parameters, including PhA at uni- and multivariate analysis were performed. Linear regression analysis demonstrated that lower level of PhA is associated with reduction in grip strength (y=3.16+0.08x; r=0.49; pstrength β=0.245, p=0.031; muscular mass β=0.623, pstrength in elderly subjects and it may be considered a good bioelectrical marker to identify elderly patients at risk of sarcopenia. Copyright © 2014 Elsevier Inc. All rights reserved.

  10. Percentiles of body fat measured by bioelectrical impedance in children and adolescents from Bogotá (Colombia): the FUPRECOL study.

    Science.gov (United States)

    Escobar-Cardozo, Germán D; Correa-Bautista, Jorge E; González-Jiménez, Emilio; Schmidt-RioValle, Jacqueline; Ramírez-Vélez, Robinson

    2016-04-01

    The analysis of body composition is a fundamental part of nutritional status assessment. The objective of this study was to establish body fat percentiles by bioelectrical impedance in children and adolescents from Bogotá (Colombia) who were part of the FUPRECOL study (Asociación de la Fuerza Prensil con Manifestaciones Tempranas de Riesgo Cardiovascular en Niños y Adolescentes Colombianos - Association between prehensile force and early signs of cardiovascular risk in Colombian children and adolescents). This was a cross-sectional study conducted among 5850 students aged 9-17.9 years old from Bogotá (Colombia). Body fat percentage was measured using foot-to-foot bioelectrical impedance (Tanita®, BF-689), by age and gender. Weight, height, waist circumference, and hip circumference were measured, and sexual maturity was self-staged. Percentiles (P3, P10, P25, P50, P75, P90 and P97) and centile curves were estimated using the LMS method (L [BoxCox curve], M [median curve] and S [variation coefficient curve]), by age and gender. Subjects included were 2526 children and 3324 adolescents. Body fat percentages and centile curves by age and gender were established. For most age groups, values resulted higher among girls than boys. Participants with values above P90 were considered to have a high cardiovascular risk due to excess fat (boys > 23.428.3, girls > 31.0-34.1). Body fat percentage percentiles measured using bioelectrical impedance by age and gender are presented here and may be used as reference to assess nutritional status and to predict cardiovascular risk due to excess fat at an early age. Sociedad Argentina de Pediatría.

  11. Prediction of fat-free body mass from bioelectrical impedance among 9- to 11-year-old Swedish children

    DEFF Research Database (Denmark)

    Nielsen, Birgit Marie; Dencker, M; Ward, L

    2007-01-01

    linear regression and cross-validated against DXA measurements of body composition. RESULTS: FFM was predicted from BIA and anthropometric variables with an adjusted R(2)= 0.95 and root mean square error (RMSE) = 0.84 kg, and LTM was predicted with an adjusted R(2)= 0.95 and RMSE = 0.87 kg. Cross......-energy X-ray absorptiometry (DXA) as the reference measurement of body composition. METHODS: The study population consisted of 49 girls and 52 boys aged 9-11 years from Malmö, Sweden. Bioelectrical impedance was measured between hand and foot at 50 kHz. Predictive equations were developed by multiple...

  12. Whole-body versus segmental bioelectrical impedance analysis in patients with edema of the upper limb after breast cancer treatment.

    Science.gov (United States)

    Berlit, Sebastian; Brade, Joachim; Tuschy, Benjamin; Földi, Etelka; Walz-Eschenlohr, Ulrike; Leweling, Hans; Sütterlin, Marc

    2013-08-01

    The purpose of this study was to compare whole-body (50 kHz alternating current) and segmental (5 kHz alternating current) bioelectrical impedance analysis (BIA) in the assessment of manifested edema of the upper limbs. Whole-body and segmental BIA were performed in 30 patients with edema of the upper limb following breast cancer treatment. Pearson correlation coefficient comparing both measurements was 0.8891 (p-value <0.0001) with corresponding least squares (r(2)) of 0.7904. Whole-body BIA seems to be a suitable method in the assessment of manifested edema of the upper limbs.

  13. Body water distribution in severe obesity and its assessment from eight-polar bioelectrical impedance analysis.

    Science.gov (United States)

    Sartorio, A; Malavolti, M; Agosti, F; Marinone, P G; Caiti, O; Battistini, N; Bedogni, G

    2005-02-01

    To measure body water distribution and to evaluate the accuracy of eight-polar bioelectrical impedance analysis (BIA) for the assessment of total body water (TBW) and extracellular water (ECW) in severe obesity. Cross-sectional study. Obesity clinic. In all, 75 women aged 18-66 y, 25 with body mass index (BMI) between 19.1 and 29.9 kg/m(2) (ie not obese), 25 with BMI between 30.0 and 39.9 kg/m(2) (ie class I and II obese), and 25 with BMI between 40.0 and 48.2 kg/m(2) (ie class III obese). TBW and ECW were measured by (2)H(2)O and Br dilution. Body resistance (R) was obtained by summing the resistances of arms, trunk and legs as measured by eight-polar BIA (InBody 3.0, Biospace, Seoul, Korea). The resistance index at a frequency of x kHz (RI(x)) was calculated as height (2)/R(x). ECW : TBW was similar in women with class III (46+/-3%, mean+/-s.d.) and class I-II obesity (45+/-3%) but higher than in nonobese women (39+/-3%, P<0.05). In a random subsample of 37 subjects, RI(500) explained 82% of TBW variance (P<0.0001) and cross-validation of the obtained algorithm in the remaining 38 subjects gave a percent root mean square error (RMSE%) of 5% and a pure error (PE) of 2.1 l. In the same subjects, RI(5) explained 87% of ECW variance (P<0.0001) and cross-validation of the obtained algorithm gave a RMSE% of 8% and a PE of 1.4 l. The contribution of weight and BMI to the prediction of TBW and ECW was nil or negligible on practical grounds. ECW : TBW is similar in women with class I-II and class III obesity up to BMI values of 48.2 kg/m(2). Eight-polar BIA offers accurate estimates of TBW and ECW in women with a wide range of BMI (19.1-48.2 kg/m(2)) without the need of population-specific formulae.

  14. Feasibility of bioelectrical impedance analysis in persons with severe intellectual and visual disabilities.

    Science.gov (United States)

    Havinga-Top, A M; Waninge, A; van der Schans, C P; Jager-Wittenaar, H

    2015-12-01

    Body composition measurements provide important information about physical fitness and nutritional status. People with severe intellectual and visual disabilities (SIVD) have an increased risk for altered body composition. Bioelectrical impedance analysis (BIA) has been evidenced as a reliable and non-invasive method to asses body composition in healthy persons and various patient populations; however, currently, there is no feasible method available to determine body composition in people with SIVD. In this study, therefore, we aimed to assess the feasibility of BIA measurements in persons with SIVD. In 33 participants with SIVD and Gross Motor Functioning Classification System (GMFCS) Scale I, II, III, or IV, two BIA measurements were sequentially performed employing Resistance and Reactance in Ohm and fat-free mass (FFM) in kg as outcome variables, utilizing the Bodystat(®) QuadScan 4000. Feasibility was considered sufficient if ≥ 80% of the first measurement was performed successfully. Agreement between two repeated measurements was determined by using the paired t-test and Intraclass Correlation Coefficient (ICC; two way random, absolute agreement). Bland-Altman analyses were utilized to determine limits of agreement (LOAs) and systematic error. Agreement was considered acceptable if LOAs were <10% of the mean of the first measurement. The first BIA measurements were completed successfully in 88% of the participants. The paired t-test demonstrated no significant differences in Resistance, Reactance, and FFM between BIA Measurements 1 and 2 (P=0.140, 0.091, and 0.866). ICC was 0.965 (95% CI: 0.922-0.984) for Resistance; 0.858 (95% CI: 0.705-0.934) for Reactance; and 0.992 (95% CI: 0.982-0.996) for FFM. LOAs expressed as a percentage of the mean of Measurement 1 were 6.1% for Resistance, 17.6% for Reactance, and 3.8% for FFM. The results of this study suggest that BIA measurements seem to be feasible in persons with SIVD. Although these results require

  15. [Predictive accuracy of body mass index in estimating body fatness measured by bioelectrical impedance].

    Science.gov (United States)

    Carrasco, Fernando; Reyes, Eliana; Rimler, Olga; Rios, Francisca

    2004-09-01

    The aim of this study was to determinate the performance of body mass index (BMI) for the diagnosis of obesity and as a predictor of body fatness in adult Chilean subjects. We conducted a study in 433 women (18-73 years old; BMI: 19.7 to 69.7 kg/m2) and 264 men (18-83 y.; BMI: 19.1 to 54.8 kg/m2). Bioelectrical resistance was measured by impedance method and fat mass percent (FM%) was calculated by fatness-specific equations developed by Segal et al. Obesity was defined as a BMI of at least 30 kg/m2. Increased fatness was defined by the FM% cut-off points of at least 25% for men and at least 30% for women. Sixty-four percent of women and 23.6% of men with BMI below 30 kg/m2 had FM% higher than 30% and 25%, respectively. A value of BMI of 26 kg/m2 in women and 30 kg/m2 in men had the best agreement to the cut-off points of fatness according to sensitivity vs. specificity analysis The following equations were developed to predict individual fatness: women FM% = 0.96 x BMI + 0.154 x age + 1.44 (r2 = 0.75; standard error 3.8%); men FM% = 0.99 x BMI + 0.141 x age - 9.914 (r2 = 0.66; standard error 4.4%). Differences between measured and predicted FM% presented a wide variation, with a range of +/- 2 sd of 7.5% in women and 8.8% in men. The commonly used value of BMI 330 kg/m2 as a cut-off point for obesity does not have adequate sensitivity and specificity for the screening of increased fatness subjects, specially in women. In this study BMI shows a low reliability as a predictor of individual body fatness, particularly in men and in subjects with a BMI below 30 kg/m2.

  16. Nutritional status and body composition by bioelectrical impedance vector analysis: A cross sectional study in mild cognitive impairment and Alzheimer's disease.

    Science.gov (United States)

    Cova, Ilaria; Pomati, Simone; Maggiore, Laura; Forcella, Marica; Cucumo, Valentina; Ghiretti, Roberta; Grande, Giulia; Muzio, Fulvio; Mariani, Claudio

    2017-01-01

    Analysis of nutritional status and body composition in Alzheimer's disease (AD) and Mild Cognitive Impairment (MCI). A cross-sectional study was performed in a University-Hospital setting, recruiting 59 patients with AD, 34 subjects with MCI and 58 elderly healthy controls (HC). Nutritional status was assessed by anthropometric parameters (body mass index; calf, upper arm and waist circumferences), Mini Nutritional Assessment (MNA) and body composition by bioelectrical impedance vector analysis (BIVA). Variables were analyzed by analysis of variance and subjects were grouped by cognitive status and gender. Sociodemographic variables did not differ among the three groups (AD, MCI and HC), except for females' age, which was therefore used as covariate in a general linear multivariate model. MNA score was significantly lower in AD patients than in HC; MCI subjects achieved intermediate scores. AD patients (both sexes) had significantly (p<0.05) higher height-normalized impedance values and lower phase angles (body cell mass) compared with HC; a higher ratio of impedance to height was found in men with MCI with respect to HC. With BIVA method, MCI subjects showed a significant displacement on the RXc graph on the right side indicating lower soft tissues (Hotelling's T2 test: men = 10.6; women = 7.9;p < 0,05) just like AD patients (Hotelling's T2 test: men = 18.2; women = 16.9; p<0,001). Bioelectrical parameters significantly differ from MCI and AD to HC; MCI showed an intermediate pattern between AD and HC. Longitudinal studies are required to investigate if BIVA could reflect early AD-changes in body composition in subjects with MCI.

  17. Influence of Posture and Frequency Modes in Total Body Water Estimation Using Bioelectrical Impedance Spectroscopy in Boys and Adult Males

    Science.gov (United States)

    Kagawa, Masaharu; Wishart, Connie; Hills, Andrew P.

    2014-01-01

    The aim of the study was to examine differences in total body water (TBW) measured using single-frequency (SF) and multi-frequency (MF) modes of bioelectrical impedance spectroscopy (BIS) in children and adults measured in different postures using the deuterium (2H) dilution technique as the reference. Twenty-three boys and 26 adult males underwent assessment of TBW using the dilution technique and BIS measured in supine and standing positions using two frequencies of the SF mode (50 kHz and 100 kHz) and the MF mode. While TBW estimated from the MF mode was comparable, extra-cellular fluid (ECF) and intra-cellular fluid (ICF) values differed significantly (p impedance. PMID:24803099

  18. Postoperative changes in body composition--comparison of bioelectrical impedance analysis and magnetic resonance imaging in bariatric patients.

    Science.gov (United States)

    Otto, Mirko; Färber, Julia; Haneder, Stefan; Michaely, Henrik; Kienle, Peter; Hasenberg, Till

    2015-02-01

    Roux-en-Y gastric bypass (RYGB) result in a marked reduction of body fat and also visceral fat (VF) decrease up to 36 % in 16 weeks. This leads to positive effects on cardiometabolic risks, which are known to be correlated with the occurrence of VF. This study analyzed the validity of bioelectrical impedance analysis (BIA) for determining VF in the postoperative course. In addition, magnetic resonance imaging (MRI) was performed for prediction of whole VF in bariatric patients on the basis of a single slice. Eighteen patients, who underwent RYGB (18), were included in this study. MRI and BIA measurements were performed 1 day before surgery, as well as 6, 12, and 24 weeks after surgery. During the postoperative observation period, we found a significant decrease of both subcutaneous fat (SF) and VF. SF measured by MRI was highly correlated with the level of body fat shown by BIA. In contrast, the VF volume, as determined by MRI, showed no correlation with the body fat measured by BIA. In addition, we were able to show a significant correlation between MRI measured VF volume and the particular single-layer fat area. Compared to the widely used bioelectrical impedance analysis to measure changes in body composition after bariatric procedures, a single-layer MRI was superior in determining VF. Single-layer MRI may be a better tool to recognize changes of VF after bariatric procedures.

  19. Bioimpedance Vector Pattern in Taiwanese and Polish College Students Detected by Bioelectric Impedance Vector Analysis: Preliminary Observations

    Directory of Open Access Journals (Sweden)

    Teresa Malecka-Massalska

    2012-01-01

    Full Text Available Background and Objectives. The study was conducted to evaluate soft tissue hydration and mass through pattern analysis of vector plots as height, normalized resistance, and reactance measurements by bioelectric impedance vector analysis in Taiwanese and Polish college students. Methods. Whole-body measurements were made with ImpediMed bioimpedance analysis SFB7 BioImp v1.55 (Pinkenba Qld 4008, Australia in 16 Taiwanese and Polish men and 16 Taiwanese and Polish women. Results. Mean vectors of Taiwanese men and women groups versus the Polish men and women groups were characterized by almost the same normalized resistance component with reactance component (separate 95% confidence limits, <0.05 indicating that there were no differences of soft tissue hydration and mass. Interpretation and Conclusion. The evaluation of soft tissue hydration and mass through pattern analysis of vector plots as height, normalized resistance, and reactance measurements by bioelectric impedance vector analysis in Taiwanese and Polish college students did not differ between these two diverse ethnic groups. Further observational research investigating these properties in larger groups would be welcomed to elucidate and/or confirm these findings.

  20. Bioelectrical impedance analysis and anthropometry for the determination of body composition in rats: effects of high-fat and high-sucrose diets

    Directory of Open Access Journals (Sweden)

    Larissa Rodrigues Neto Angéloco

    2012-06-01

    Full Text Available OBJECTIVE: The aim of the present study was to determine the impedance of Wistar rats treated with high-fat and high-sucrose diets and correlate their biochemical and anthropometric parameters with chemical analysis of the carcass. METHODS: Twenty-four male Wistar rats were fed a standard (AIN-93, high-fat (50% fat or high-sucrose (59% of sucrose diet for 4 weeks. Abdominal and thoracic circumference and body length were measured. Bioelectrical impedance analysis was used to determine resistance and reactance. Final body composition was determined by chemical analysis. RESULTS: Higher fat intake led to a high percentage of liver fat and cholesterol and low total body water in the High-Fat group, but these changes in the biochemical profile were not reflected by the anthropometric measurements or bioelectrical impedance analysis variables. Anthropometric and bioelectrical impedance analysis changes were not observed in the High-Sucrose group. However, a positive association was found between body fat and three anthropometric variables: body mass index, Lee index and abdominal circumference. CONCLUSION: Bioelectrical impedance analysis did not prove to be sensitive for detecting changes in body composition, but body mass index, Lee index and abdominal circumference can be used for estimating the body composition of rats.

  1. Validity of segmental bioelectrical impedance analysis for estimating fat-free mass in children including overweight individuals.

    Science.gov (United States)

    Ohta, Megumi; Midorikawa, Taishi; Hikihara, Yuki; Masuo, Yoshihisa; Sakamoto, Shizuo; Torii, Suguru; Kawakami, Yasuo; Fukunaga, Tetsuo; Kanehisa, Hiroaki

    2017-02-01

    This study examined the validity of segmental bioelectrical impedance (BI) analysis for predicting the fat-free masses (FFMs) of whole-body and body segments in children including overweight individuals. The FFM and impedance (Z) values of arms, trunk, legs, and whole body were determined using a dual-energy X-ray absorptiometry and segmental BI analyses, respectively, in 149 boys and girls aged 6 to 12 years, who were divided into model-development (n = 74), cross-validation (n = 35), and overweight (n = 40) groups. Simple regression analysis was applied to (length) 2 /Z (BI index) for each of the whole-body and 3 segments to develop the prediction equations of the measured FFM of the related body part. In the model-development group, the BI index of each of the 3 segments and whole body was significantly correlated to the measured FFM (R 2 = 0.867-0.932, standard error of estimation = 0.18-1.44 kg (5.9%-8.7%)). There was no significant difference between the measured and predicted FFM values without systematic error. The application of each equation derived in the model-development group to the cross-validation and overweight groups did not produce significant differences between the measured and predicted FFM values and systematic errors, with an exception that the arm FFM in the overweight group was overestimated. Segmental bioelectrical impedance analysis is useful for predicting the FFM of each of whole-body and body segments in children including overweight individuals, although the application for estimating arm FFM in overweight individuals requires a certain modification.

  2. Predictive validity of four bioelectrical impedance equations in determining percent fat mass in overweight and obese children.

    Science.gov (United States)

    Cleary, Jane; Daniells, Suzie; Okely, Anthony D; Batterham, Marijka; Nicholls, Jessie

    2008-01-01

    Bioelectrical impedance equations are frequently used by food and nutrition professionals to estimate percent fat mass in overweight and obese children. However, it is not known whether they are accurate for such children, as they have been primarily developed for children of varying body weights. The aim of this cross-sectional study was to evaluate the predictive validity of four previously published prediction equations developed for the pediatric population, among a sample of overweight and obese children. Thirty overweight or obese children (mean age=7.57+/-1.28 years) underwent measurement of fat mass, percent fat mass, and fat-free mass using dual-energy x-ray absorptiometry (DEXA) and bioelectrical impedance analysis (BIA). Impedance values from the BIA were entered into the four prediction equations and Pearson correlations used to determine the significance of associations between each of the BIA prediction equations and DEXA for percent fat mass, fat mass, and fat-free mass. For percent fat mass, paired t tests were used to assess differences between the methods and the technique of Bland and Altman was used to determine bias and error. Results showed that the mean percent fat mass as determined by DEXA for this age group was 40.79%. In comparison with other BIA prediction equations, the Schaefer equation had the closest mean value of 41.98%, and was the only equation not to significantly differ from the DEXA (P=0.121). This study suggests that the Schaefer equation is the only accurate BIA prediction equation for assessing percent fat mass in this sample of overweight and obese children from primarily white backgrounds.

  3. Bioelectrical impedance analysis to estimate body composition in children and adolescents: a systematic review and evidence appraisal of validity, responsiveness, reliability and measurement error

    NARCIS (Netherlands)

    Talma, H.; Chinapaw, M.J.M.; Bakker, B.; Hirasing, R.A.; Terwee, C.B.; Altenburg, T.M.

    2013-01-01

    Bioelectrical impedance analysis (BIA) is a practical method to estimate percentage body fat (%BF). In this systematic review, we aimed to assess validity, responsiveness, reliability and measurement error of BIA methods in estimating %BF in children and adolescents.We searched for relevant studies

  4. The Effect of an Acute After-School Exercise Bout on Percentage of Body Fat Using Leg-to-Leg Bioelectrical Impedance Analysis in Children

    Science.gov (United States)

    Andreacci, Joseph L.; Dixon, Curt B.; Rompolski, Krista; VanGorden, Kelly M.

    2008-01-01

    Bioelectrical impedance analysis (BIA) is a fast, easy to administer, and relatively inexpensive method of evaluating body composition. Due to the ease of operation, interest in using BIA to estimate percentage of body fat (%BF) has grown, especially in settings where body composition assessments are often performed without the benefit of…

  5. Effect of Exercise Intensity on Percent Body Fat Determined by Leg-to-Leg and Segmental Bioelectrical Impedance Analyses in Adults

    Science.gov (United States)

    Andreacci, Joseph L.; Nagle, Trisha; Fitzgerald, Elise; Rawson, Eric S.; Dixon, Curt B.

    2013-01-01

    Purpose: We examined the impact that cycle ergometry exercise had on percent body fat (%BF) estimates when assessed using either leg-to-leg or segmental bioelectrical impedance analysis (LBIA; SBIA) and whether the intensity of the exercise bout impacts the %BF magnitude of change. Method: Seventy-four college-aged adults participated in this…

  6. Evaluation of total body water in canine breeds by single-frequency bioelectrical impedance analysis method: specific equations are needed for accuracy.

    Science.gov (United States)

    Yaguiyan-Colliard, Laurence; Daumas, Caroline; Nguyen, Patrick; Grandjean, Dominique; Cardot, Philippe; Priymenko, Nathalie; Roux, Françoise

    2015-08-06

    Equations based on single-frequency bioelectrical impedance analysis at 50 kHz for determination of total body water content (TBW) have been previously validated in healthy non-sedated beagle dogs. We investigated whether these equations are predictive of TBW in various canine breeds by comparing the results of these equations with TBW values evaluated directly by deuterium oxide (D2O) dilution. Total body water content of 13 healthy adult pet dogs of various breeds was determined directly using D2O dilution and indirectly using previous equations based on values obtained with a portable bioelectric impedance device. Paired Student's t-tests were used to compare TBW obtained by single-frequency bioelectrical impedance analysis and D2O dilution. A p-value of bioelectrical impedance analysis parameters validated at 50 kHz in healthy adult beagles need to be modified including morphological parameters such as body size and shape in a first approach. As in humans, morphological-specific equations have to be developed and validated.

  7. Measuring body composition in dogs using multifrequency bioelectrical impedance analysis and dual energy X-ray absorptiometry.

    Science.gov (United States)

    Rae, L S; Vankan, D M; Rand, J S; Flickinger, E A; Ward, L C

    2016-06-01

    Thirty-five healthy, neutered, mixed breed dogs were used to determine the ability of multifrequency bioelectrical impedance analysis (MFBIA) to predict accurately fat-free mass (FFM) in dogs using dual energy X-ray absorptiometry (DXA)-measured FFM as reference. A second aim was to compare MFBIA predictions with morphometric predictions. MFBIA-based predictors provided an accurate measure of FFM, within 1.5% when compared to DXA-derived FFM, in normal weight dogs. FFM estimates were most highly correlated with DXA-measured FFM when the prediction equation included resistance quotient, bodyweight, and body condition score. At the population level, the inclusion of impedance as a predictor variable did not add substantially to the predictive power achieved with morphometric variables alone; in individual dogs, impedance predictors were more valuable than morphometric predictors. These results indicate that, following further validation, MFBIA could provide a useful tool in clinical practice to objectively measure FFM in canine patients and help improve compliance with prevention and treatment programs for obesity in dogs. Copyright © 2016. Published by Elsevier Ltd.

  8. Assessment of fat-free mass from bioelectrical impedance analysis in obese women with Prader-Willi syndrome.

    Science.gov (United States)

    Bedogni, Giorgio; Grugni, Graziano; Tringali, Gabriella; Agosti, Fiorenza; Sartorio, Alessandro

    2015-01-01

    Fat-free mass (FFM) is lower in obese subjects with Prader-Willi syndrome (PWS) than in obese subjects without PWS. FFM prediction equations developed in non-PWS subjects may, thus, not work in PWS subjects. To test whether the estimation of FFM from bioelectrical impedance analysis (BIA) in PWS subjects requires population-specific equations. Using dual-energy X-ray absorptiometry, this study measured FFM in 27 PWS and 56 non-PWS obese women and evaluated its association with the impedance index at 50 kHz (ZI50), i.e. the ratio between squared height and whole-body impedance at 50 kHz. At the same level of ZI50, PWS women had a lower FFM than non-PWS women. However, when PWS-specific equations were used, FFM was accurately estimated at the population level. An equation employing a dummy variable coding for PWS status was able to explain 85% of the variance of FFM with a root mean squared error of 3.3 kg in the pooled sample (n = 83). Population-specific equations are needed to estimate FFM from BIA in obese PWS women.

  9. Segmental bioelectrical impedance analysis (SBIA) and blood rheology: Reducing the gap between in vivo and in vitro?

    Science.gov (United States)

    Varlet-Marie, Emmanuelle; Joré, Céline; Brun, Jean-Frédéric

    2016-01-01

    Bioelectrical impedancemetry (BIA) has been used to evaluate hematocrit and red cell aggregability in vitro but whole body impedance measurements are also correlated to some hemorheologic factors, suggesting a relationship between viscosity factors and electric properties of blood. We repeatedly reported correlations with whole body BIA and hematocrit, whole blood viscosity and plasma viscosity, red cell rigidity and RBC aggregation. The SBIA Inbody 770 modelizes body as 5 cylinders and measures impedance at 1, 5, 50, 250, 500, and 1000 kHz. With the SBIA we found that hematocrit is best correlated to leg reactance at 50 kHz but also to leg impedance at 1 and 5 kHz and trunk reactance. RBC aggregation "M" is best correlated to arm reactance at 5 kHz but also to most measurements of segmental impedance (28 correlations found). RBC aggregation "M1" is best correlated to arm reactance at 5 kHz and to 19 other impedance measurements. A predictive equation for "M" from the mean between the two arm reactances at 5 kHz (maXc5) is found: M = 2.1845maXc5-23.958 (r = 0.665, p < 0.001) that provides a satisfactory Bland-Altman plot (mean difference: 0.000524 range [-1.6;+1.6]. This study suggests that previously reported correlations between BIA and viscosity factors were not spurious, and that in a narrow cylinder such as the arm the structure of circulating blood (hematocrit, red cell aggregation) may influence the passage of an electric current by increasing reactance.

  10. Inter-sport variability of muscle volume distribution identified by segmental bioelectrical impedance analysis in four ball sports

    Directory of Open Access Journals (Sweden)

    Yamada Y

    2013-04-01

    Full Text Available Yosuke Yamada,1,2 Yoshihisa Masuo,3 Eitaro Nakamura,4 Shingo Oda5 1Laboratory of Sports and Health Science, Kyoto Prefectural University of Medicine, Kyoto, Japan; 2Japan Society for the Promotion of Science, Tokyo, Japan; 3Waseda University Research Institute for Elderly Health, Saitama, Japan; 4Department of Sport Science, Kyoto Iken College of Medicine and Health, Kyoto, Japan; 5Faculty of Health and Well-being, Kansai University, Osaka, Japan Abstract: The aim of this study was to evaluate and quantify differences in muscle distribution in athletes of various ball sports using segmental bioelectrical impedance analysis (SBIA. Participants were 115 male collegiate athletes from four ball sports (baseball, soccer, tennis, and lacrosse. Percent body fat (%BF and lean body mass were measured, and SBIA was used to measure segmental muscle volume (MV in bilateral upper arms, forearms, thighs, and lower legs. We calculated the MV ratios of dominant to nondominant, proximal to distal, and upper to lower limbs. The measurements consisted of a total of 31 variables. Cluster and factor analyses were applied to identify redundant variables. The muscle distribution was significantly different among groups, but the %BF was not. The classification procedures of the discriminant analysis could correctly distinguish 84.3% of the athletes. These results suggest that collegiate ball game athletes have adapted their physique to their sport movements very well, and the SBIA, which is an affordable, noninvasive, easy-to-operate, and fast alternative method in the field, can distinguish ball game athletes according to their specific muscle distribution within a 5-minute measurement. The SBIA could be a useful, affordable, and fast tool for identifying talents for specific sports. Keywords: discriminant analysis, cluster and factor analysis, segmental bioelectrical impedance analysis, baseball, lacrosse

  11. Comparison of Body Fat Results from 4 Bioelectrical Impedance Analysis Devices vs. Air Displacement Plethysmography in American Adolescent Wrestlers

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    Melissa M. Montgomery

    2017-10-01

    Full Text Available Background: Accurate and accessible methods of body composition are necessary to ensure health and safety of wrestlers during competition. The most valid and reliable instruments are expensive and relatively inaccessible to high school wrestlers; therefore, more practical technology is needed. Objective: To compare body fat percentage (BF% results from 4 bioelectrical impedance analysis (BIA devices to those from air displacement plethysmography (ADP in adolescent wrestlers. Methodology: 134 adolescent male and female wrestlers (1.72±0.9 m, 66.8±14.3 kg, 15.6±1.1 yrs. were tested for hydration and then completed 4 body composition tests with different BIA devices and one with Bod Pod. Relative and absolute agreement were assessed between each BIA device and ADP on a single day. Results: When compared with ADP, all devices demonstrated excellent reliability (ICC (2,1 range: 0.88-0.94, but questionable measurement error (SEM range: 2.3-3.6 %BF. Bland-Altman plots revealed that each bioelectrical impedance device we tested over-estimated body fat percent in high school wrestlers (range: 0.8-3.6 %BF and demonstrated wide 95% limits of agreement (range: 15.0-20.8 %BF compared to ADP. Conclusions: The devices investigated demonstrated reasonable measurement accuracy. However, wide margins of error of each device were noted. Caution should be taken when assessing adolescent wrestlers with lower amounts of body fat, as it may result in failing to identify those who do not meet the minimum body fat percentage for competition. The governing bodies should use the research data in the decision-making process regarding appropriate devices for use in their weight management programs.

  12. Stratification of fat-free mass index percentiles for body composition based on NHANES III bioelectric impedance data

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    Kudsk, Kenneth A.; Munoz-del-Rio, Alejandro; Busch, Rebecca A.; Kight, Cassandra E.; Schoeller, Dale A.

    2015-01-01

    Background Loss of protein mass and lower fat-free mass index (FFMI) are associated with longer length of stay, post-surgical complications and other poor outcomes in hospitalized patients Normative data for FFMI of U.S. populations does not exist. This work aims to create a stratified FFMI percentile table for the U.S. population using the large bioelectric impedance analysis data obtained from National Health and Nutrition Examination Surveys (NHANES). Methods Fat-free mass (FFM) was calculated from the NHANES III bioelectric impedance analysis and anthropometric data for males and females ages 12 to over 90 years for three race-ethnicities (non-Hispanic white, non-Hispanic black, and Mexican-American). FFM was normalized by subject height to create a FFMI distribution table for the U.S. population. Selected percentiles were obtained by age, sex, and race-ethnicity. Data was collapsed by race-ethnicity before and after removing obese and underweight subjects to create a FFMI decile table for males and females aged 12 and over for the healthy weight U.S. population. Results FFMI increased during adolescent growth but stabilized in the early 20s. The FFMI deciles were similar by race-ethnicity and age group remaining relatively stable between ages of 22 and 80 years. The FFMI deciles for males and females were significantly different. Conclusions After eliminating the obese and extremely thin, FFMI percentiles remain stable during adult years allowing creation of age- and race/ethnicity-independent decile tables for males and females. These tables allow stratification of individuals for nutrition intervention trials to depict changing nutrition status during medical, surgical and nutritional interventions. PMID:26092851

  13. The use of bioelectrical impedance analysis to estimate total body water in young children with cerebral palsy.

    Science.gov (United States)

    Bell, Kristie L; Boyd, Roslyn N; Walker, Jacqueline L; Stevenson, Richard D; Davies, Peter S W

    2013-08-01

    Body composition assessment is an essential component of nutritional evaluation in children with cerebral palsy. This study aimed to validate bioelectrical impedance to estimate total body water in young children with cerebral palsy and determine best electrode placement in unilateral impairment. 55 young children with cerebral palsy across all functional ability levels were included. Height/length was measured or estimated from knee height. Total body water was estimated using a Bodystat 1500MDD and three equations, and measured using the gold standard, deuterium dilution technique. Comparisons were made using Bland Altman analysis. For children with bilateral impairment, the Fjeld equation estimated total body water with the least bias (limits of agreement): 0.0 L (-1.4 L to 1.5 L); the Pencharz equation produced the greatest: 2.7 L (0.6 L-4.8 L). For children with unilateral impairment, differences between measured and estimated total body water were lowest on the unimpaired side using the Fjeld equation 0.1 L (-1.5 L to 1.6 L)) and greatest for the Pencharz equation. The ability of bioelectrical impedance to estimate total body water depends on the equation chosen. The Fjeld equation was the most accurate for the group, however, individual results varied by up to 18%. A population specific equation was developed and may enhance the accuracy of estimates. Australian New Zealand Clinical Trials Registry (ANZCTR) number: ACTRN12611000616976. Copyright © 2012 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.

  14. Validity of bioelectrical impedance analysis to estimate body composition changes after bariatric surgery in premenopausal morbidly women.

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    Savastano, Silvia; Belfiore, Annamaria; Di Somma, Carolina; Mauriello, Concetta; Rossi, Annalisa; Pizza, Genoveffa; De Rosa, Annalba; Prestieri, Giovanni; Angrisani, Luigi; Colao, Annamaria

    2010-03-01

    In obese patients, subtle variations of the hydration of soft tissues can propagate errors in bioelectrical impedance analysis (BIA) measures of body composition. Bioelectrical impedance vector analysis (BIVA) is a useful method to evaluate tissue hydration. Laparoscopic adjustable gastric banding (LAGB) is a purely restrictive bariatric surgical procedure resulting in lower fat-free mass (FFM) loss than other malabsorptive or mixed intervention. The aim of this study was to evaluate the 6- and 12-month changes in body composition in a homogeneous group of premenopausal morbidly obese women treated by LAGB by comparing the results of conventional BIA and BIVA with dual-energy X-ray absorptiometry (DXA) method. Forty-five consecutive morbidly obese patients (mean age, 35.3 +/- 9.1 years; body mass index, 34.5-48.7 kg/m(2)) were prospectively evaluated at the Endocrinology Unit of the Department of Molecular and Clinical Endocrinology and Oncology. The LAGB device (Lap-Band System; Inamed Health, Santa Barbara, CA, USA) was inserted laparoscopically. Soft tissue hydration was evaluated by BIVA; fat mass (FM) and FFM were evaluated by BIA (BIA 101 RJL, Akern Bioresearch, Firenze, Italy) and by DXA (Hologic QDR 4500A S/N 45622; Hologic Inc., Bedford, MA, USA). Pre- and postoperative BIVA vectors indicated a normal hydration in all patients. Postoperatively, the excess of body weight loss was mainly due to a decrease in FM. The regression analysis of BIA and DXA methods at baseline and at the 6- and 12-month follow-up for FM r (2) values were 0.98, 0.94, and 0.99, respectively (p obese subjects. BIA tends to overestimate FFM, but this effect is reduced along with the weight loss during the follow-up. Under the stable hydration, the BIA method may be useful as an alternative to DXA in a selected clinical setting when repeated comparisons of body composition are required.

  15. Indirect prediction of total body water content in healthy adult Beagles by single-frequency bioelectrical impedance analysis.

    Science.gov (United States)

    Yaguiyan-Colliard, Laurence; Daumas, Caroline; Bousbiat, Sana; Jaffrin, Michel; Cardot, Philippe; Grandjean, Dominique; Priymenko, Nathalie; Nguyen, Patrick; Roux, Françoise

    2015-06-01

    To develop equations for prediction of total body water (TBW) content in unsedated dogs by combining impedance (resistance and reactance) and morphological variables and to compare the results of those equations with TBW content determined by deuterium dilution (TBW(d)). 26 healthy adult Beagles. TBW content was determined directly by deuterium dilution and indirectly with equations developed from measurements obtained by use of a portable bioelectric impedance device and morphological variables including body length, height, weight, and thoracic and abdominal circumferences. Impedance and morphological data from 16 of the 26 dogs were used to determine coefficients for the following 2 equations: TBW(1) = -0.019 (BL(2)/R) + -0.199 (RC + AC) + 0.996 W + 0.081 H + 12.31; and TBW(2) = 0.048 (BL(2)/R) + -0.144 (RC + AC) + 0.777 W + 0.066 H + 0.031 X + 7.47, where AC is abdominal circumference, H is height, BL is body length, R is resistance, RC is rib cage circumference, W is body weight, and × is reactance. Results for TBW(1) (R(2)(1) = 0.843) and TBW(2) (R(2)(2) = 0.816) were highly correlated with the TBW(d). When the equations were validated with data from the remaining 10 dogs, the respective mean differences between TBW(d) and TBW(1) and TBW(2) were 0.17 and 0.11 L, which equated to a nonsignificant underestimation of TBW content by 2.4% and 1.6%, respectively. Results indicated that impedance and morphological data can be used to accurately estimate TBW content in adult Beagles. This method of estimating TBW content is less expensive and easier to perform than is measurement of TBW(d), making it appealing for daily use in veterinary practice.

  16. Calibration of bioelectrical impedance analysis for body composition assessment in Ethiopian infants using air-displacement plethysmography.

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    Wibæk, R; Kæstel, P; Skov, S R; Christensen, D L; Girma, T; Wells, J C K; Friis, H; Andersen, G S

    2015-10-01

    Assessment of infant body composition (BC) is crucial to understand the consequences of suboptimal nutritional status and postnatal growth, and the effects of public health interventions. Bioelectrical impedance analysis (BIA) is a feasible, relatively inexpensive and noninvasive method for assessing BC. However, very little research has been conducted in low- and middle-income populations, where efforts to prevent or treat malnutrition in early life are a public health priority. We aimed to develop equations for predicting fat-free mass (FFM) and fat mass (FM) based on BIA in 0- to 6-month-old Ethiopian infants. The study comprised a total of 186 BC assessments performed in 101 healthy infants, delivered at Jimma University Specialized Hospital. Infant air-displacement plethysmography (IADP) was the criterion method, whereas weight, length, sex, age and an impedance index (L(2)/Z50) were predictors. Prediction equations were developed using stepwise multiple linear regression and the accuracy was evaluated with a 10-fold cross-validation approach. A linear regression model based on body weight, age and sex predicted FFM, estimated by IADP, with an adjusted R(2) and root mean square error (RMSE) of 0.94 and 200 g, respectively. Adding impedance index to the model resulted in a significantly improved model fit (R(2)=0.95; RMSE=181 g). For infants below 3 months of age, inclusion of impedance index did not contribute to an improved model fit for predicting FFM compared with a model already comprising weight, sex and age. The derived equations predicted FFM with acceptable accuracy and may be used in future field surveys, epidemiological studies and clinical trials conducted in similar sub-Saharan African population groups aged 0-6 months.

  17. Single-cell bioelectrical impedance platform for monitoring cellular response to drug treatment

    Science.gov (United States)

    Asphahani, Fareid; Wang, Kui; Thein, Myo; Veiseh, Omid; Yung, Sandy; Xu, Jian; Zhang, Miqin

    2011-02-01

    The response of cells to a chemical or biological agent in terms of their impedance changes in real-time is a useful mechanism that can be utilized for a wide variety of biomedical and environmental applications. The use of a single-cell-based analytical platform could be an effective approach to acquiring more sensitive cell impedance measurements, particularly in applications where only diminutive changes in impedance are expected. Here, we report the development of an on-chip cell impedance biosensor with two types of electrodes that host individual cells and cell populations, respectively, to study its efficacy in detecting cellular response. Human glioblastoma (U87MG) cells were patterned on single- and multi-cell electrodes through ligand-mediated natural cell adhesion. We comparatively investigated how these cancer cells on both types of electrodes respond to an ion channel inhibitor, chlorotoxin (CTX), in terms of their shape alternations and impedance changes to exploit the fine detectability of the single-cell-based system. The detecting electrodes hosting single cells exhibited a significant reduction in the real impedance signal, while electrodes hosting confluent monolayer of cells showed little to no impedance change. When single-cell electrodes were treated with CTX of different doses, a dose-dependent impedance change was observed. This enables us to identify the effective dose needed for this particular treatment. Our study demonstrated that this single-cell impedance system may potentially serve as a useful analytical tool for biomedical applications such as environmental toxin detection and drug evaluation.

  18. Validation of equations using anthropometric and bioelectrical impedance for estimating body composition of the elderly

    Directory of Open Access Journals (Sweden)

    Cassiano Ricardo Rech

    2006-08-01

    Full Text Available The increase of the elderly population has enhanced the need for studying aging-related issues. In this context, the analysis of morphological alterations occurring with the age has been discussed thoroughly. Evidences point that there are few information on valid methods for estimating body composition of senior citizens in Brazil. Therefore, the objective of this study was to cross-validate equations using either anthropometric or bioelectrical impedance (BIA data for estimation of body fat (%BF and of fat-free mass (FFM in a sample of older individuals from Florianópolis-SC, having the dual energy x-ray absorptiometry (DEXA as the criterion-measurement. The group was composed by 180 subjects (60 men and 120 women who participated in four community Groups for the elderly and were systematically randomly selected by a telephone interview, with age ranging from 60 to 81 years. The variables stature, body mass, body circumferences, skinfold thickness, reactance and resistance were measured in the morning at The Sports Center of the Federal University of Santa Catarina. The DEXA evaluation was performed in the afternoon at The Diagnosis Center through Image in Florianópolis-SC. Twenty anthropometric and 8 BIA equations were analyzed for cross-validation. For those equations that estimate body density, the equation of Siri (1961 and the adapted-equation by Deurenberg et al. (1989 were used for conversion into %BF. The analyses were performed with the statistical package SPSS, version 11.5, establishing the level of significance at 5%. The criteria of cross-validation suggested by Lohman (1992 and the graphic dispersion analyses in relation to the mean, as proposed by Bland and Altman (1986 were used. The group presented values for the body mass index (BMI between 18.4kg.m-2 and 39.3kg.m-2. The mean %BF was of 23.1% (sd=5.8 for men and 37.3% (sd=6.9 in women, varying from 6% to 51.4%. There were no differences among the estimates of the equations

  19. The effect of a meal on measures of impedance and percent body fat estimated using contact-electrode bioelectrical impedance technology.

    Science.gov (United States)

    Dixon, C B; Masteller, B; Andreacci, J L

    2013-09-01

    To determine the effect of a meal on impedance and percent body fat (%BF) determined using contact-electrode bioelectrical impedance analysis (BIA) technology. Forty-three adults (23 women and 20 men) volunteered to participate in this study (age=20.5±1.1 years; body mass index=24.1±3.8 kg/m(2)). Body composition was assessed using three BIA analyzers: leg-to-leg (LBIA), segmental (SBIA) and multi-frequency (MFBIA), on two separate occasions. After a baseline measurement, subjects consumed a meal or received nothing, which served as the control (CON). Subjects were reassessed 20, 40 and 60 min following (POST) the baseline measure in each condition. Twenty minutes after eating (3847±900 kJ), body mass (LBIA=0.8 kg, SBIA=0.8 kg, MFBIA=0.7 kg, Pimpedance (LBIA=6.0 Ω, SBIA=17.9 Ω, MFBIA=27.1 Ω, Pimpedance increase (4-9 Ω) was observed over time resulting in a small increase in %BF (0.3-0.7%) 60 min POST (Pimpedance and body mass. As such, when precision is critical, we recommend adhering to the pretest fasting guidelines to avoid meal-induced alterations in %BF estimates. In addition, use of a consistent testing schedule may minimize normal %BF variation over time.

  20. Influence of Posture and Frequency Modes in Total Body Water Estimation Using Bioelectrical Impedance Spectroscopy in Boys and Adult Males

    Directory of Open Access Journals (Sweden)

    Masaharu Kagawa

    2014-05-01

    Full Text Available The aim of the study was to examine differences in total body water (TBW measured using single-frequency (SF and multi-frequency (MF modes of bioelectrical impedance spectroscopy (BIS in children and adults measured in different postures using the deuterium (2H dilution technique as the reference. Twenty-three boys and 26 adult males underwent assessment of TBW using the dilution technique and BIS measured in supine and standing positions using two frequencies of the SF mode (50 kHz and 100 kHz and the MF mode. While TBW estimated from the MF mode was comparable, extra-cellular fluid (ECF and intra-cellular fluid (ICF values differed significantly (p < 0.01 between the different postures in both groups. In addition, while estimated TBW in adult males using the MF mode was significantly (p < 0.01 greater than the result from the dilution technique, TBW estimated using the SF mode and prediction equation was significantly (p < 0.01 lower in boys. Measurement posture may not affect estimation of TBW in boys and adult males, however, body fluid shifts may still occur. In addition, technical factors, including selection of prediction equation, may be important when TBW is estimated from measured impedance.

  1. Biochemical and anthropometric correlates of bio-electrical impedance parameters in severely malnourished children

    DEFF Research Database (Denmark)

    Girma, Tsinuel; Nielsen, Anne-Louise Hother; Kæstel, Pernille

    2018-01-01

    INTRODUCTION: Despite expanding use of bio-impedance (BI), little is known about its pathophysiologic significance and biological correlates OBJECTIVE: Determine correlations of BI parameters with anthropometry and biomarkers of electrolyte homeostasis, inflammation and liver function in children...

  2. [Measuring bioelectric myocardial impedance as a noninvasive method for diagnosis of graft rejection after heart transplantation].

    Science.gov (United States)

    Pfitzmann, R; Müller, J; Grauhan, O; Cohnert, T; Hetzer, R

    1998-04-01

    12 beagle dogs underwent neck-heart transplantation and were immunosuppressed with cyclosporine and methylprednisolone. Intramyocardial impedance was determined twice daily with four screw-in electrodes in the right and left ventricle. Transmyocardial biopsies and the intra-myocardial electrogram (IMEG) were performed as reference methods. 19 rejection episodes were induced. When acute rejection was seen in histology the animals were treated with pulsed 125 mg methylprednisolone over 5 consecutive days and immunosuppression was raised to sufficient levels. Successful treatment of rejection was controlled by biopsy. All hearts showed a uniform decrease of impedance of about 28.3% +/- 5.5% immediately after implantation, then reaching a stable plateau after 7 to 8 days. Impedance values then remained unchanged as long as rejection was absent. Biopsy findings of grade 1A to 1B (ISHLT) were accompanied by a statistically significant increase of impedance of 12.2% +/- 2.5%, of grade 2 to 3A of 19.2% +/- 3.2%, and of grade 3B to 4 of 27.0% +/- 2.9%. Sensitivity was 95%, specificity 91%. Successful treatment of rejection led to a uniform decrease of impedance to intramyocardial impedance for high frequencies can reliably indicate alterations of the cell membrane and the intracellular space during acute cardiac allograft rejection. The amount of increase of impedance is a reliable noninvasive parameter to graduate acute cardiac allograft rejection. The success of treatment of rejection can also be monitored by impedance. This noninvasive method is applicable for telemetric rejection monitoring via an implantable device, which would allow continuous rejection surveillance of a patient at home without hospital admission.

  3. Effective and timely evaluation of pulmonary congestion: qualitative comparison between lung ultrasound and thoracic bioelectrical impedance in maintenance hemodialysis patients.

    Science.gov (United States)

    Donadio, Carlo; Bozzoli, Laura; Colombini, Elisa; Pisanu, Giovanna; Ricchiuti, Guido; Picano, Eugenio; Gargani, Luna

    2015-02-01

    The assessment of pulmonary congestion in maintenance hemodialysis (MHD) patients is challenging. Bioelectrical impedance analysis (BIA) can estimate body water compartments. Natriuretic peptides are markers of hemodynamic stress, neurohormonal activation and extracellular volume overload. Lung ultrasound (LUS) has been proposed for the non-invasive estimation of extravascular lung water through B-lines assessment. Up to now, no study evaluated the correlation between B-lines, segmental thoracic BIA, and natriuretic peptides in MHD patients. The aims of this study were: (1) To validate LUS as a tool for an effective and timely evaluation of pulmonary congestion in MHD patients, in comparison with segmental thoracic BIA, and with natriuretic peptides; (2) To compare a comprehensive whole chest ultrasound scanning with a simplified and timely scanning scheme limited to the lateral chest regions.Thirty-one MHD adult patients were examined. LUS, total body and thoracic BIA, and natriuretic peptides were performed immediately before and after a mid-week dialysis session. The number of B-lines assessed by LUS was compared with total body and thoracic impedance data and with natriuretic peptides.Pre-HD B-lines ranged 0-147 (mean 31) and decreased significantly post-HD (mean 16, P impedance (r = 0.30, P impedance than with total body impedance, and correlated with extra-cellular but not with intra-cellular water index. The correlation between B-lines and ECWI was similar when LUS was limited to the lateral chest regions or performed on the whole chest. Multivariate analysis showed that only segmental thoracic impedance was an independent predictor of residual pulmonary congestion.The dynamic changes in B-lines after hemodialysis are correlated to the changes in total body and extra-cellular water, and particularly to lung fluids removal. B-line assessment in MHD patients is highly feasible with a simplified and timely scanning scheme limited to the lateral chest

  4. Proximal electrode placement improves the estimation of body composition in obese and lean elderly during segmental bioelectrical impedance analysis.

    Science.gov (United States)

    Yamada, Yosuke; Masuo, Yoshihisa; Yokoyama, Keiichi; Hashii, Yukako; Ando, Soichi; Okayama, Yasuko; Morimoto, Taketoshi; Kimura, Misaka; Oda, Shingo

    2009-09-01

    Bioelectrical impedance analysis (BIA) is an affordable, non-invasive, easy-to-operate, and fast alternative method to assess body composition. However, BIA tends to overestimate the percent body fat (%BF) in lean elderly and underestimate %BF in obese elderly people. This study examined whether proximal electrode placement eliminates this problem. Forty-two elderly men and women (64-96 years) who had a wide range of BMI [22.4 +/- 3.3 kg/m(2) (mean +/- SD), range 16.8-33.9 kg/m(2)] and %BF (11.3-44.8%) participated in this study. Using (2)H and (18)O dilutions as the criterion for measuring total body water (TBW), we compared various BIA electrode placements; wrist-to-ankle, arm-to-arm, leg-to-leg, elbow-to-knee, five- and nine-segment models, and the combination of distal (wrists or ankles) and proximal (elbows or knees) electrodes. TBW was most strongly correlated with the square height divided by the impedance between the knees and elbows (H(2)/Z (proximal); r = 0.965, P impedance ratio of the proximal to distal segments (P/D) as an independent variable, none of the BIA methods examined showed any systematic bias against %BF. In addition, all methods were able to estimate TBW more accurately (e.g., in the wrist-to-ankle model, from R(2) = 0.90, SEE = 1.69 kg to R(2) = 0.94, SEE = 1.30 kg). The results suggest that BIA using distal electrodes alone tends to overestimate TBW in obese and underestimate TBW in lean subjects, while proximal electrodes improve the accuracy of body composition measurements.

  5. Performance of abdominal bioelectrical impedance analysis and comparison with other known parameters in predicting the metabolic syndrome.

    Science.gov (United States)

    Mousa, U; Kut, A; Bozkus, Y; Cicek Demir, C; Anil, C; Bascil Tutuncu, N

    2013-07-01

    Although obesity is a powerful risk factor for metabolic syndrome (MetS) it is not present in all obese individuals. Increased visceral adipose tissue is the hallmark of this syndrome. In this cross sectional survey we aimed to use abdominal bioelectrical impedance analysis to measure the visceral adipose tissue (VAT) and trunk fat percentages (TF%) in the study population, correlate these findings with traditional anthropometric measures and biochemical parameters of metabolic syndrome and estimate a cut-off value of visceral fat for development of MetS. A total of 285 subjects were enrolled. VAT and TF% were measured by the AB-140 device via abdominal bioelectrical impedance analysis. Fat% was measured by a body composition analyzer (TBF-300). VAT was significantly positively correlated with body mass index, waist circumference, TF%, HOMA IR, fat percentage, fasting plasma glucose and triglycerides. Strongest correlations were between VAT and TF%, VAT and device measured waist circumference and between VAT and manual waist circumference (r=0.95, r=0.93, r=0.92 respectively). Correlations of VAT and TF% with metabolic parameters were significant but weak. The mean VAT and TF% in MetS (+) groups were significantly higher than patients in MetS (-) groups in both sexes. The areas under the ROC curves were 0.730 (95% CI: 0.661-0.791) for female VAT and 0.702 (95% CI: 0.654-0.749) for male VAT in predicting MetS which were similar to the areas under ROC curves calculated for device and manually measured waist circumference, HOMA IR and TF% in predicting MetS (p>0.05 for all comparisons). The accuracy of VAT and TF% for predicting MetS was not sufficient. From our results we can deduce that the performance of abdominal BIA in predicting MetS is weak but could be used in the follow-up of patients with obesity and/or MetS. This has to be confirmed in future studies. © Georg Thieme Verlag KG Stuttgart · New York.

  6. Validation of bioelectrical impedance analysis for estimating limb lean mass in free-living Caucasian elderly people.

    Science.gov (United States)

    De Rui, Marina; Veronese, Nicola; Bolzetta, Francesco; Berton, Linda; Carraro, Sara; Bano, Giulia; Trevisan, Caterina; Pizzato, Simona; Coin, Alessandra; Perissinotto, Egle; Manzato, Enzo; Sergi, Giuseppe

    2017-04-01

    Aging is characterized by a loss of limb lean mass (LLM) that can lead to physical disability and death. Regional bioelectrical impedance analysis (BIA) may be a reliable method for estimating LLM, but no prediction equations are available for elderly Caucasian subjects. The aim of this study was to develop and validate a BIA-based equation for predicting LLM in healthy elderly Caucasians, taking dual X-ray absorptiometry (DXA) as the reference method. Using a cross-sectional design, 244 free-living healthy Caucasian subjects (117 men, 179 women) over 60 years of age were enrolled. LLM was measured with DXA (LLM DXA ), and the resistance (Rz) and reactance (Xc) of each limb were measured with a regional bioelectrical impedance analyzer. A resistive index (RI) was calculated from stature in meters divided by Rz of each arm. A BIA-based multiple regression equation for predicting the lean mass (LM) of dominant and non-dominant limbs was developed using a double cross-validation technique. Using the sample as a whole, cross-validation resulted in an equation specific for each limb, as follows, where sex equals 1 for males, and 0 for females: LM (kg) = -0.081 + (0.061*RI) + (0.010*body weight) + (0.299*sex) for the dominant arm; LM (kg) = -0.026 + (0.014*RI) + (0.009*body weight) + (0.352*sex) for the non-dominant arm; LM (kg) = -0.462 + (0.027*RI) + (0.047*body weight) + (0.639*sex) + (0.026*Xc) for the dominant leg; and for the non-dominant leg, LM (kg) = -0.522 + (0.029*RI) + (0.045*body weight) + (0.569*sex) + (0.025*Xc). The DXA-measured and BIA-predicted LLM for each limb did not differ significantly. Our newly-developed BIA equations seem to provide a valid estimation of LLM in older Caucasian adults. Copyright © 2016 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.

  7. Association of plasma adiponectin levels with cellular hydration state measured using bioelectrical impedance analysis in patients with COPD

    Directory of Open Access Journals (Sweden)

    Yoshikawa T

    2012-08-01

    Full Text Available Takahiro Yoshikawa,1 Hiroshi Kanazawa21Department of Sports Medicine, Osaka City University Graduate School of Medicine, 2Department of Respiratory Medicine, Osaka City University Graduate School of Medicine, Osaka, JapanBackground: It is widely recognized that chronic obstructive pulmonary disease (COPD includes a variety of extra pulmonary complications and comorbidities. Recently, adiponectin was shown to regulate cellular metabolism in humans. Cellular hydration state is affected by a variety of hormonal factors and regulates cellular metabolic state. Therefore, this study was designed to determine whether adiponectin is a possible factor involved in cellular hydration state in COPD.Methods: Thirty patients with COPD and 41 age-matched controls participated in the study. Plasma levels of total and high molecular weight (HMW adiponectin were measured and anthropometry and pulmonary function tests were conducted. Intracellular water (ICW, extracellular water (ECW, and ECW/ICW ratio, which are parameters of cellular hydration state, were measured using bioelectrical impedance analysis.Results: Higher levels of total and HMW adiponectin in plasma were found in patients with COPD compared with levels in controls. A significant inverse correlation was observed between body mass index and plasma levels of total and HMW adiponectin in the control group. However, this significant correlation was not observed in patients with COPD. The plasma levels of total and HMW adiponectin were also not significantly correlated with any pulmonary function parameters in patients with COPD. Regarding the state of cellular hydration, the plasma levels of total adiponectin were inversely correlated with the ECW/ICW ratio and positively with ICW values in patients with COPD. Moreover, closer correlations were found between these parameters and plasma HMW adiponectin levels.Conclusion: The results of the present study suggest a novel association of the plasma

  8. Bioelectrical impedance analysis for assessment of fluid status and body composition in neonates--the good, the bad and the unknown.

    Science.gov (United States)

    Lingwood, B E

    2013-01-01

    There is a critical need for improved technologies to monitor fluid balance and body composition in neonates, particularly those receiving intensive care. Bioelectrical impedance analysis meets many of the criteria required in this environment and appears to be effective for monitoring physiological trends. The literature regarding the use of bioelectrical impedance in neonates was reviewed. It was found that prediction equations for total body water, extracellular water and fat-free mass have been developed, but many require further testing and validation in larger cohorts. Alternative approaches based on Hanai mixture theory or vector analysis are in the early stages of investigation in neonates. Further research is required into electrode positioning, bioimpedance spectroscopy and Cole analysis in order to realise the full potential of this technology.

  9. BIOELECTRICAL IMPEDANCE TECHNOLOGY FOR EVALUATING HUMAN BODY COMPOSITION PARAMETERS: “AN ADVANCED DIAGNOSTIC TECHNOLOGY FOR BODY COMPOSITION AND PHYSICAL FITNESS ANALYSIS”

    OpenAIRE

    Rohit Subhedar; Vaibhavi Subhedar; Pallavi Dave; Priyanka Mishra; Ankit Kaur

    2014-01-01

    Enormous use of sophisticated technology in daily living has resulted in lifestyle disorders in form of obesity, hypertension, cardiac disorders and musculoskeletal problems in a community as a whole. This significant rise in physically unfit community prompted us to find a most cost-effective, simple, and reliable mode of physical fitness evaluation in form of Bioelectrical Impedance technology. An observational randomized experimental study was conducted at Multispecialty Department of Phys...

  10. Multi-frequency bioelectrical impedance analysis (BIA) compared to magnetic resonance imaging (MRI) for estimation of fat-free mass in colorectal cancer patients treated with chemotherapy

    DEFF Research Database (Denmark)

    Palle, Stine Skov; Tang Møllehave, Line; Kadkhoda, Zahra Taheri

    2016-01-01

    Background: Changes in body composition in cancer patients during chemotherapy are associated with treatment related toxicities or mortalities. Thus, it is relevant to identify accessible, relatively inexpensive, portable and reliable tools for evaluation of body composition in cancer patients...... during the course of their treatments. Objective: To examine relationships between single cross-sectional thighs magnetic resonance imaging (MRI), skeletal muscle mass (SM) as reference and multi-frequency bioelectrical impedance analysis (BIA) fat free mass (FFM) in patients with colorectal cancer...

  11. The investigation of the some body parameters of obese and (obese+diabetes) patients with using bioelectrical impedance analysis techniques

    Science.gov (United States)

    Yerlikaya, Emrah; Karageçili, Hasan; Aydin, Ruken Zeynep

    2016-04-01

    Obesity is a key risk for the development of hyperglycemia, hypertension, hyperlipidemia, insulin resistance and is totally referred to as the metabolic disorders. Diabetes mellitus, a metabolic disorder, is related with hyperglycemia, altered metabolism of lipids, carbohydrates and proteins. The minimum defining characteristic feature to identify diabetes mellitus is chronic and substantiated elevation of circulating glucose concentration. In this study, it is aimed to determine the body composition analyze of obese and (obese+diabetes) patients.We studied the datas taken from three independent groups with the body composition analyzer instrument. The body composition analyzer calculates body parameters, such as body fat ratio, body fat mass, fat free mass, estimated muscle mass, and base metabolic rate on the basis of data obtained by Dual Energy X-ray Absorptiometry using Bioelectrical Impedance Analysis. All patients and healthy subjects applied to Siirt University Medico and their datas were taken. The Statistical Package for Social Sciences version 21 was used for descriptive data analysis. When we compared and analyzed three groups datas, we found statistically significant difference between obese, (obese+diabetes) and control groups values. Anova test and tukey test are used to analyze the difference between groups and to do multiple comparisons. T test is also used to analyze the difference between genders. We observed the statistically significant difference in age and mineral amount plifestyle.

  12. Prediction of fat-free body mass from bioelectrical impedance and anthropometry among 3-year-old children using DXA

    Science.gov (United States)

    Ejlerskov, Katrine T.; Jensen, Signe M.; Christensen, Line B.; Ritz, Christian; Michaelsen, Kim F.; Mølgaard, Christian

    2014-01-01

    For 3-year-old children suitable methods to estimate body composition are sparse. We aimed to develop predictive equations for estimating fat-free mass (FFM) from bioelectrical impedance (BIA) and anthropometry using dual-energy X-ray absorptiometry (DXA) as reference method using data from 99 healthy 3-year-old Danish children. Predictive equations were derived from two multiple linear regression models, a comprehensive model (height2/resistance (RI), six anthropometric measurements) and a simple model (RI, height, weight). Their uncertainty was quantified by means of 10-fold cross-validation approach. Prediction error of FFM was 3.0% for both equations (root mean square error: 360 and 356 g, respectively). The derived equations produced BIA-based prediction of FFM and FM near DXA scan results. We suggest that the predictive equations can be applied in similar population samples aged 2–4 years. The derived equations may prove useful for studies linking body composition to early risk factors and early onset of obesity. PMID:24463487

  13. Assessment of gender differences in body composition and physical fitness scoring in Saudi adults by bioelectrical impedance analysis.

    Science.gov (United States)

    Al Dokhi, Laila; Habib, Syed Shahid

    2013-06-01

    Obesity is a global problem that is reaching epidemic proportions. Body composition is an important parameter for humans because previous studies indicate high values of body fat as a predictor of mortality. The aim of the study was to assess gender differences in body composition and physical fitness in Saudi adult population. This epidemiological cross-sectional study included 411 healthy adult Saudi subjects aged 18-72 years (mean +/- SD, 36.91 +/- 15.22). All participants underwent body composition analysis. Body composition was assessed by bioelectrical impedance analysis, with a commercially available body analyzer (InBody 3.0, Biospace, Seoul, Korea). Measurements included body weight, body mass index (BMI), percent body fat, target weight, fat control, muscle control and fitness scoring based on target values. The mean BMI of the whole study population was 27.22 +/- 5.65 (median = 26.80, range = 15.6-55.4). The mean fitness score was 69.3 +/- 8.48 (median = 71.0, range = 29-99). Significant gender differences were observed in BMI, fitness score, percent body fat, and other parameters of body composition. In conclusion, the prevalence of obesity, percent body fat (%BF) and poor fitness is high in Saudi population with significant gender differences. In this regard, public awareness programs including exercise and diet teaching are required at large scale to cope up with the growing burden of obesity.

  14. Comparison of Standing Posture Bioelectrical Impedance Analysis with DXA for Body Composition in a Large, Healthy Chinese Population.

    Science.gov (United States)

    Chen, Kuen-Tsann; Chen, Yu-Yawn; Wang, Chia-Wei; Chuang, Chih-Lin; Chiang, Li-Ming; Lai, Chung-Liang; Lu, Hsueh-Kuan; Dwyer, Gregory B; Chao, Shu-Ping; Shih, Ming-Kuei; Hsieh, Kuen-Chang

    2016-01-01

    Bioelectrical impedance analysis (BIA) is a common method for assessing body composition in research and clinical trials. BIA is convenient but when compared with other reference methods, the results have been inconclusive. The level of obesity degree in subjects is considered to be an important factor affecting the accuracy of the measurements. A total of 711 participants were recruited in Taiwan and were sub-grouped by gender and levels of adiposity. Regression analysis and Bland-Altman analysis were used to evaluate the agreement of the measured body fat percentage (BF%) between BIA and DXA. The BF% measured by the DXA and BIA methods (Tanita BC-418) were expressed as BF%DXA and BF%BIA8, respectively. A one-way ANOVA was used to test the differences in BF% measurements by gender and levels of adiposity. The estimated BF%BIA8 and BF%DXA in the all subjects, male and female groups were all highly correlated (r = 0.934, 0.901, 0.916, all Pobesity degree in both male and female subjects.

  15. Validity of bioelectrical impedance analysis for measuring changes in body water and percent fat after bariatric surgery.

    Science.gov (United States)

    Widen, Elizabeth M; Strain, Gladys; King, Wendy C; Yu, Wenwen; Lin, Susan; Goodpaster, Bret; Thornton, John; Courcoulas, Anita; Pomp, Alfons; Gallagher, Dympna

    2014-06-01

    Few studies have validated bioelectrical impedance analysis (BIA) following bariatric surgery. We examined agreement of BIA (Tanita 310) measures of total body water (TBW) and percent body fat (%fat) before (T0) and 12 months (T12) after bariatric surgery, and change between T0 and T12 with reference measures: deuterium oxide dilution for TBW and three-compartment model (3C) for %fat in a subset of participants (n = 50) of the Longitudinal Assessment of Bariatric Surgery-2. T0 to T12 median (IQR) change in deuterium TBW and 3C %fat was -6.4 L (6.4 L) and -14.8% (13.4%), respectively. There were no statistically significant differences between deuterium and BIA determined TBW [median (IQR) difference: T0 -0.1 L (7.1 L), p = 0.75; T12 0.2 L (5.7 L), p = 0.35; Δ 0.35 L(6.3 L), p = 1.0]. Compared with 3C, BIA underestimated %fat at T0 and T12 [T0 -3.3 (5.6), p obese adults. However, clinically meaningful differences in the accuracy of BIA between individuals exist.

  16. Body composition in heavy smokers: comparison of segmental bioelectrical impedance analysis and dual-energy X-ray absorptiometry.

    Science.gov (United States)

    Rom, O; Reznick, A Z; Keidar, Z; Karkabi, K; Aizenbud, D

    2015-01-01

    Smokers tend to have lower body mass index, on one hand, and increased abdominal obesity, on the other hand. Also, low levels of lean mass (LM) and bone mineral content (BMC) were found among older smokers compared with non-smokers. This altered body composition and its consequences raise the need for simple and reliable methods for assessment of body composition in smokers. This study aimed to compare body composition assessment by segmental bioelectrical impedance analysis (sBIA) with the reference method, dual energy X-ray absorptiometry (DEXA). Body composition was measured by sBIA (Tanita BC-545) and DEXA (Hologic) in 49 heavy smokers (>15 cigarettes/day, mean age 43.8±12.0). The comparison included correlations and differences between measurements obtained using the two methods as well as the Blande-Altman analysis. Whole-body fat mass (FM) and LM measured by the two methods were found to be highly correlated (r>0.9, p0.9, p<0.001). However, sBIA significantly overestimated LM of the trunk and legs and underestimated the appendicular FM percentage. Verified by DEXA, sBIA provides reliable measures of whole-body LM, FM, and trunk FM in heavy smokers. A lesser degree of agreement was found for BMC, appendicular LM, and FM.

  17. Bioelectrical impedance for measuring percentage body fat in young persons with Down syndrome: validation with dual-energy absorptiometry.

    Science.gov (United States)

    Loveday, Sarah J; Thompson, John M D; Mitchell, Edwin A

    2012-11-01

    Children with Down syndrome have an increased prevalence of obesity, although there is little work describing body composition in this population. The aims of this study were to accurately measure body fat in children with Down syndrome and to identify which existing algorithm best predicts percentage body fat in this population. Seventy children with Down syndrome had anthropometric, bioelectrical impedance analysis (BIA) and dual-energy X-ray absorptiometry (DXA) data collected to calculate percentage body fat (PBF). Pearson correlations were carried out to assess the relationships of various methods for measuring body fat and Bland-Altman plots to assess systematic error. Mean PBF was 30.5% for girls and 22.5% for boys. A total of 38% of girls and 23% of boys were obese according to international criteria. PBF as determined by DXA correlated well with PBF by BIA in both girls and boys (r = 0.91 and 0.89, respectively, p obesity in children with Down syndrome. BIA can be used to accurately determine adiposity in this population. We recommend the use of the Schaeffer algorithm for calculation of PBF in children with Down syndrome. © 2012 The Author(s)/Acta Paediatrica © 2012 Foundation Acta Paediatrica.

  18. Accuracy of quantitative magnetic resonance and eight-electrode bioelectrical impedance analysis in normal weight and obese women.

    Science.gov (United States)

    Bosaeus, Marja; Karlsson, Therese; Holmäng, Agneta; Ellegård, Lars

    2014-06-01

    Quantitative magnetic resonance (QMR) has previously been shown to both overestimate and underestimate average fat mass (FM) in humans. Eight-electrode bioelectrical impedance analysis (BIA) has previously been found biased as well as successfully validated. We report cross-sectional accuracy of QMR and eight-electrode BIA evaluated with air displacement plethysmography (ADP) as reference method. Fat mass and fat free mass (FFM) by QMR and eight-electrode BIA were evaluated against ADP as reference in 38 normal weight and 30 obese women. Total body water estimates by QMR and eight-electrode BIA were compared. Fat mass was overestimated by QMR (1 ± 2 kg, p obese women. Fat free mass biases were of similar magnitude but in opposite direction to FM biases. Total body water estimates were larger by eight-electrode BIA compared to QMR (1-10 kg). Fat mass and FFM by QMR were both biased but in opposite directions in both normal weight and obese women. Eight-electrode BIA FM and FFM estimates were imprecise and biased in obese women. Thus, QMR is more precise and more accurate than eight-electrode BIA for estimating body composition in women, but is not accurate enough to be used for individual single assessment of body composition. Copyright © 2013 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.

  19. Different body fluid volumes measured by single- and multi-frequency bioelectrical impedance analyzers in overweight/obese renal patients.

    Science.gov (United States)

    Kusztal, Mariusz; Dzierżek, Przemysław; Gołębiowski, Tomasz; Weyde, Wacław; Klinger, Marian

    2015-05-17

    Bioelectrical impedance analysis (BIA) is an affordable, non-invasive and fast alternative method to assess body composition. The purpose of this study was to compare two different tetrapolar BIA devices for estimating body fluid volumes and body cell mass (BCM) in a clinical setting among patients with kidney failure. All double measurements were performed by multi-frequency (MF) and single-frequency (SF) BIA analyzers: a Body Composition Monitor (Fresenius Medical Care, Germany) and BIA-101 (Akern, Italy), respectively. All procedures were conducted according to the manufacturers' instructions (dedicated electrodes, measurement sites, positions, etc). Total body water (TBW), extracellular water (ECW), intracellular water (ICW) and BCM were compared. The study included 39 chronic kidney disease patients (stage III-V) with a mean age of 45.8 ± 8 years (21 men and 18 women) who had a wide range of BMI [17-34 kg/m2 (mean 26.6 ±5)]. A comparison of results from patients with BMI obese renal patients.

  20. Obesity in Korean pre-adolescent school children: comparison of various anthropometric measurements based on bioelectrical impedance analysis.

    Science.gov (United States)

    Yoo, S; Lee, S-Y; Kim, K-N; Sung, E

    2006-07-01

    To examine the relationships between body mass index (BMI), percentage-weight-for-height (PWH) and percentage body fat (PBF), and to compare their validity based on PBF with the BMI criteria of International Obesity Task Force (IOTF) for childhood obesity in Korean pre-adolescent school children. Statistical comparative analysis for anthropometric measures. Korean pre-adolescent children (438 boys and 454 girls, aged 8-12 years, mean BMI 19.5+/-3.4 kg/m2). Body mass index and PWH were calculated as body size indices from height and weight. Hand-to-foot bioelectrical impedance analysis (BIA) was performed to obtain PBF values, with obese children defined as PBF above 35%. Sensitivity and specificity were displayed with the gold standard of PBF, and receiver operating characteristic (ROC) curves were used to assess the performance of BMI and PWH in detecting obesity. The prevalence of obesity varied by the criteria: 18.8% by Korean BMI standards for 95 percentile, 11% by the IOTF-BMI 30 kg/m2 and 29.4% by Korean PWH cutoffs. Body mass index and PWH were significantly correlated with PBF after adjusting for age, 0.910 (Pobesity among Korean pre-adolescent children widely varied according to the diagnostic criteria applied. Universally recommended cutoffs for children by IOTF showed the lowest sensitivity among the criteria used, and may therefore underestimate obesity in this population.

  1. Relationship between Height-Weight Difference Index and Body-Fat Percentage Estimated by Bioelectrical Impedance Analysis in Thai Adults.

    Science.gov (United States)

    Juntaping, Kanokkarn; Chittawatanarat, Kaweesak; Prasitwattanaseree, Sukon; Chaijaruwanich, Jeerayut; Traisathit, Patrinee

    2017-01-01

    The height-weight difference index (HWDI) is a new indicator for evaluating obesity status. While body-fat percentage (BF%) is considered to be the most accurate obesity evaluation tool, it is a more expensive method and more difficult to measure than the others. Our objectives were to find the relationship between HWDI and BF% and to find a BF% prediction model from HWDI in relation to age and gender. Bioelectrical impedance analysis was used to measure BF% in 2,771 healthy adult Thais. HWDI was calculated as the difference between height and weight. Pearson's correlation coefficient was used to assess the relationship between HWDI and BF%. Multiple linear and nonlinear regression analysis were used to construct the BF% prediction model. HWDI and BF% were found to be inverse which related to a tendency toward a linear relationship. Results of a multivariate linear regression analysis, which included HWDI and age as variables in the model, predicted BF% to be 34.508 - 0.159 (HWDI) + 0.161 (age) for men and 53.35 - 0.265 (HWDI) + 0.132 (age) for women. The prediction model provides an easy-to-use obesity evaluation tool that should help awareness of underweight and obesity conditions.

  2. Predictive capacity of different bioelectrical impedance analysis devices, with and without protocol, in the evaluation of adolescents.

    Science.gov (United States)

    Gonçalves, Vivian Siqueira Santos; Faria, Eliane Rodrigues de; Franceschini, Sylvia do Carmo Castro; Priore, Silvia Eloiza

    2013-01-01

    this study was performed to determine the predictive capacity of four different bioelectrical impedance analysis (BIA) devices in the assessment of adolescents, with and without a protocol. a cross-sectional study was performed with 215 adolescents aged 10 to 14 years, of both genders, evaluated through anthropometry and body composition by dual energy X-ray absorptiometry (DXA) and by four different BIA devices, with and without a protocol. The following tests were used: Kolmogorov-Smirnov's, chi-squared, Student's t or Mann-Whitney's, Kruskal-Wallis's, Wilcoxon's, and kappa index. The ROC curves were constructed and the sensitivity, specificity, and positive and negative predictive values were calculated. of the 215 adolescents, 44.2% had excessive body fat. The tetrapolar BIA device equipped with eight tactile electrodes showed more sensitivity and results that were closer to those obtained by DXA (area under the ROC curve [AUC] = 0.964 with protocol and AUC = 0.973 without protocol, p 0.05). BIA is capable of predicting alterations in adolescents' body composition. When it is impossible to perform the assessment with a protocol, its results may be useful in population studies. Copyright © 2013 Sociedade Brasileira de Pediatria. Published by Elsevier Editora Ltda. All rights reserved.

  3. Prediction of fat-free body mass from bioelectrical impedance and anthropometry among 3-year-old children using DXA.

    Science.gov (United States)

    Ejlerskov, Katrine T; Jensen, Signe M; Christensen, Line B; Ritz, Christian; Michaelsen, Kim F; Mølgaard, Christian

    2014-01-27

    For 3-year-old children suitable methods to estimate body composition are sparse. We aimed to develop predictive equations for estimating fat-free mass (FFM) from bioelectrical impedance (BIA) and anthropometry using dual-energy X-ray absorptiometry (DXA) as reference method using data from 99 healthy 3-year-old Danish children. Predictive equations were derived from two multiple linear regression models, a comprehensive model (height(2)/resistance (RI), six anthropometric measurements) and a simple model (RI, height, weight). Their uncertainty was quantified by means of 10-fold cross-validation approach. Prediction error of FFM was 3.0% for both equations (root mean square error: 360 and 356 g, respectively). The derived equations produced BIA-based prediction of FFM and FM near DXA scan results. We suggest that the predictive equations can be applied in similar population samples aged 2-4 years. The derived equations may prove useful for studies linking body composition to early risk factors and early onset of obesity.

  4. Estimation of prevalence of sarcopenia by using a new bioelectrical impedance analysis in Chinese community-dwelling elderly people.

    Science.gov (United States)

    Wang, Hui; Hai, Shan; Cao, Li; Zhou, Jianghua; Liu, Ping; Dong, Bi-Rong

    2016-12-28

    The aim of the present study was to validate the usefulness of the new octapolar multifrequency bioelectrical impedance analysis (BIA) for assessment of appendicular skeletal muscle mass (ASM) by comparing it with that of dual-energy X-ray absorptiometry (DXA) and to investigate the prevalence of sarcopenia in Chinese community-dwelling elderly according to Asian Working Group for Sarcopenia (AWGS) definition. A cross-sectional study was conducted in communities of Chengdu, China. A total of 944 community-dwelling elderly adults aged ≥60 years were included. ASM was measured by using DXA as a criterion method to validate a standing eight-electrode multifrequency BIA (InBody 720), followed by a further estimation of the prevalence of sarcopenia according the AWGS definition. In the Bland-Altman analysis, no significant difference was found between DXA and BIA based on the ASM measurements. The prevalence of AWGS-defined sarcopenia was 12.5% in the elderly women and 8.2% in the elderly men. BIA is suitable for body composition monitoring (ASM) in elderly Chinese as a fast, noninvasive, and convenient method; therefore, it may be a better choice in large epidemiological studies in the Chinese population. The prevalence of AWGS-defined sarcopenia was approximately 10.4% and increased with age in the Chinese community-dwelling elderly in this study.

  5. Relationship between Height-Weight Difference Index and Body-Fat Percentage Estimated by Bioelectrical Impedance Analysis in Thai Adults

    Directory of Open Access Journals (Sweden)

    Kanokkarn Juntaping

    2017-01-01

    Full Text Available Introduction. The height-weight difference index (HWDI is a new indicator for evaluating obesity status. While body-fat percentage (BF% is considered to be the most accurate obesity evaluation tool, it is a more expensive method and more difficult to measure than the others. Objective. Our objectives were to find the relationship between HWDI and BF% and to find a BF% prediction model from HWDI in relation to age and gender. Method. Bioelectrical impedance analysis was used to measure BF% in 2,771 healthy adult Thais. HWDI was calculated as the difference between height and weight. Pearson’s correlation coefficient was used to assess the relationship between HWDI and BF%. Multiple linear and nonlinear regression analysis were used to construct the BF% prediction model. Results. HWDI and BF% were found to be inverse which related to a tendency toward a linear relationship. Results of a multivariate linear regression analysis, which included HWDI and age as variables in the model, predicted BF% to be 34.508 − 0.159 (HWDI + 0.161 (age for men and 53.35 − 0.265 (HWDI + 0.132 (age for women. Conclusions. The prediction model provides an easy-to-use obesity evaluation tool that should help awareness of underweight and obesity conditions.

  6. Bioelectric impedance analysis of body composition of children and adolescents with sickle cell anemia in Enugu, Nigeria.

    Science.gov (United States)

    Eke, Christopher Bismarck; Chukwu, Bartholomew Friday; Ikefuna, Anthony Nnaemeka; Ezenwosu, Osita Uchenna; Emodi, Ifeoma Josephine

    2015-05-01

    Body composition indices are widely used to evaluate growth and nutrition in children, particularly those with sickle cell anemia (SCA), who are known to have impaired growth, impaired skeletal maturation, and delayed puberty. The current study is aimed at determining the body composition of children with SCA. Consecutive selection of SCA children aged 6 to 18 years, who served as subjects and their age and gender matched children with HbAA (controls), selected using multi-stage systematic sampling. It was a cross-sectional descriptive study conducted at the pediatric hematology and oncology clinic. Bioelectric impedance analysis was used to determine the body composition parameters, including weight, body fat percentage (BFP), visceral fat percentage, body mass index (BMI), skeletal muscle percentage, and resting metabolic rate. Data were analyzed using SPSS 16.0 at P Children with SCA, particularly the older males, have impaired body composition indices. There is a need to conduct further studies to determine the longitudinal aspects of growth as well as quantitative and qualitative assessment of nutritional intake in children with SCA, which will inform higher alimentation requirements for HbSS children as compared with HbAA individuals.

  7. Bioelectrical impedance spectroscopy as a fluid management system in heart failure

    International Nuclear Information System (INIS)

    Weyer, Sören; Wartzek, Tobias; Leicht, Lennart; Leonhardt, Steffen; Zink, Matthias Daniel; Mischke, Karl; Vollmer, Thomas

    2014-01-01

    Episodes of hospitalization for heart failure patients are frequent and are often accompanied by fluid accumulations. The change of the body impedance, measured by bioimpendace spectroscopy, is an indicator of the water content. The hypothesis was that it is possible to detect edema from the impedance data. First, a finite integration technique was applied to test the feasibility and allowed a theoretical analysis of current flows through the body. Based on the results of the simulations, a clinical study was designed and conducted. The segmental impedances of 25 patients suffering from heart failure were monitored over their recompensation process. The mean age of the patients was 73.8 and their mean body mass index was 28.6. From these raw data the model parameters from the Cole model were deduced by an automatic fitting algorithm. These model data were used to classify the edema status of the patient. The baseline values of the regression lines of the extra- and intracellular resistance from the transthoracic measurement and the baseline value of the regression line of the extracellular resistance from the foot-to-foot measurement were identified as important parameters for the detection of peripheral edema. The rate of change of the imaginary impedance at the characteristic frequency and the mean intracellular resistance from the foot-to-foot measurement were identified as important parameters for the detection of pulmonary edema. To classify the data, two decision trees were considered: One should detect pulmonary edema (n pulmonary = 13, n none = 12) and the other peripheral edema (n peripheral = 12, n none = 13). Peripheral edema could be detected with a sensitivity of 100% and a specificity of 90%. The detection of pulmonary edema showed a sensitivity of 92.31% and a specificity of 100%. The leave-one-out cross-validation-error for the peripheral edema detection was 12% and 8% for the detection of pulmonary edema. This enables the application of BIS as an

  8. Validity of Standing Posture Eight-electrode Bioelectrical Impedance to Estimate Body Composition in Taiwanese Elderly

    Directory of Open Access Journals (Sweden)

    Ling-Chun Lee

    2014-09-01

    Conclusion: The results of this study showed that the impedance index and LST in the whole body, upper limbs, and lower limbs derived from DXA findings were highly correlated. The LST and BF% estimated by BIA8 in whole body and various body segments were highly correlated with the corresponding DXA results; however, BC-418 overestimates the participants' appendicular LST and underestimates whole body BF%. Therefore, caution is needed when interpreting the results of appendicular LST and whole body BF% estimated for elderly adults.

  9. Preliminary bioelectrical impedance analysis (BIA) equation for body composition assessment in young females from Colombia

    Science.gov (United States)

    Caicedo-Eraso, J. C.; González-Correa, C. H.; González-Correa, C. A.

    2013-04-01

    A previous study showed that reported BIA equations for body composition are not suitable for Colombian population. The purpose of this study was to develop and validate a preliminary BIA equation for body composition assessment in young females from Colombia, using hydrodensitometry as reference method. A sample of 30 young females was evaluated. Inclusion and exclusion criteria were defined to minimize the variability of BIA. Height, weight, BIA, residual lung volume (RV) and underwater weight (UWW) were measured. A preliminary BIA equation was developed (r2 = 0.72, SEE = 2.48 kg) by stepwise multiple regression with fat-free mass (FFM) as dependent variable and weight, height and impedance measurements as independent variables. The quality of regression was evaluated and a cross-validation against 50% of sample confirmed that results obtained with the preliminary BIA equation is interchangeable with results obtained with hydrodensitometry (r2 = 0.84, SEE = 2.62 kg). The preliminary BIA equation can be used for body composition assessment in young females from Colombia until a definitive equation is developed. The next step will be increasing the sample, including a second reference method, as deuterium oxide dilution (D2O), and using multi-frequency BIA (MF-BIA). It would also be desirable to develop equations for males and other ethnic groups in Colombia.

  10. Comparison of body fat in Brazilian adult females by bioelectrical impedance analysis

    Science.gov (United States)

    Altamir, Vaz; Frère, Slaets Annie France; Ramírez Leonardo, López

    2012-12-01

    Body-fat is essential for human body, provided that its amount is at healthy levels. If in-excess body-fat is deleterious, its lack is otherwise also harmful. Estimated percent body-fat performed with commercially available devices measuring bioimpedance have many advantages, such as easy measurement and low cost. However, these measurements are based on standard models and equations that are not disclosed by manufacturers, and this leads to questioning the validity of these estimates for Brazilian females. The aim of this study was to compare electrical tetrapolar and octapolar impedance results obtained with commercially available equipment: Maltron BF-906 and OMRON 510-W. Data analysis involved descriptive and inferential statistics. Devices used in this study to estimate body fat quantity have not shown any significant differences in results; this is a major issue when selecting equipment based on three factors: study focus, available financial resources, and target population. Results obtained from the two devices have not shown any significant differences, which lead to the conclusion that either device may be reliably used.

  11. Association of body composition assessed by bioelectrical impedance analysis with metabolic risk factor clustering among middle-aged Chinese

    Directory of Open Access Journals (Sweden)

    Linfeng Zhang

    2017-06-01

    Full Text Available Body composition monitor (BCM based on the bioelectric impedance analysis is very convenient to use. However, whether percentage body fat (PBF and visceral fat index (VFI that acquired by BCM are superior to anthropometric measures is unknown. The study explored whether PBF and VFI are better than anthropometric indexes [body mass index (BMI, waist circumference (WC and waist circumference to height ratio(WHtR] in predicating metabolic risk factor clustering in a representive sample across China which included 9574 Chinese men and women that were investigated in 2009–2010. PBF and VFI were compared with the BMI, WC, and WHtR through the area under the curve (AUC of the receiver operating characteristic (ROC curve and logistic regression. The results showed that the AUC for VFI was higher than BMI and PBF but lower than WHtR and WC in both men and Women. The AUC for WHtR, WC, VFI, BMI and PBF was 0.710, 0.706, 0.700, 0.693, 0.656 in men and 0.705, 0.699, 0.698, 0.675, 0.657 in women, respectively. After adjusting for the potential confounding factors, the odds ratios (ORs tended to increase with all the indexes. The curve of ORs for WHtR was steepest and the curve for PBF was flattest in both men and women; the curve for VFI was similar to WC in women, but flatter than WC in men. From the data we concluded that VFI seems better than BMI and PBF, but not superior to WC and WHtR in predicating metabolic risk factor clustering in the middle-aged Chinese.

  12. Anthropometric indexes outperform bioelectrical impedance analysis-derived estimates of body composition in identification of metabolic abnormalities in morbid obesity.

    Science.gov (United States)

    Perea, Verónica; Jiménez, Amanda; Flores, Lílliam; Ortega, Emilio; Coves, Maria J; Vidal, Josep

    2013-01-01

    The validity of anthropometric indexes in ascertaining the body composition (BC) in morbidly obese (MO) subjects has been questioned. Our objective was to evaluate, in MO subjects, whether bioelectrical impedance analysis (BIA) of BC is more closely associated with the metabolic syndrome (MS) and insulin resistance (IR) than are classic anthropometric measurements. The setting was a university hospital. The association between anthropometric (body mass index, waist circumference [WC]) and BIA (total fat mass [FM] [percentage of FM], truncal FM, android FM) estimates of BC, MS, and IR was evaluated in 784 white MO subjects (212 men and 572 women). BIA estimates were calculated using equations specific for MO subjects developed by our own group and validated against dual energy x-ray absorptiometry. The prevalence of the MS and IR was 78.6% and 88.6%, respectively. The body mass index was greater in women with the MS (P <.001) or IR (P <.001), and the WC was larger in subjects of both genders with the MS or IR (P <.001). Moreover, the WC correlated significantly with all the MS components (P <.05). In contrast, the percentage of FM, truncal FM, and android FM were significantly associated with the MS only in women. Stepwise logistic regression analysis demonstrated the WC as the only significant predictor of the MS or IR (both P <.001). Furthermore, receiver operating curve analysis showed WC was the most accurate BC parameter for the identification of subjects with the MS (area under the curve, WC = .681, P <.001) or IR (area under the curve, WC = .753, P <.001). In MO subjects, the BIA-derived indexes of total and central adiposity were not better predictors of the MS or IR than were traditional anthropometric measurements. Copyright © 2013 American Society for Metabolic and Bariatric Surgery. Published by Elsevier Inc. All rights reserved.

  13. Comparison of DEXA-derived body fat measurement to two race-specific bioelectrical impedance equations in healthy Indians.

    Science.gov (United States)

    Nigam, Priyanka; Misra, Anoop; Colles, Susan L

    2013-01-01

    Prevalence of obesity is increasing in Asian Indians. Reliable, precise and convenient methods to estimate body composition are required. This study aimed to test the accuracy of bioelectrical impedance analysis (BIA) estimates of body composition among Asian Indians according to two BIA equations--one developed for Asians, the other for Caucasians. Two hundred apparently healthy Asian Indians (100 males, 100 females; mean age 36.6 ± 7.6 years; mean BMI 16.6-46.7 kg/m(2)) underwent BIA assessment of fat mass (FM), fat free mass (FFM) and percentage body fat (%BF) using Tanita Multi-Frequency Body Composition Analyzer MC-180MA (Tanita Corporation, Tokyo, Japan). One set of BIA values was automatically calculated by the analyzer (Caucasian figures), the other set by Tanita (Japanese Asian figures). Results were compared to dual X-ray absorptiometry (DEXA) as the standard measure. A moderate level of relative agreement was found between the DEXA-derived measurement of %BF and the estimate from both the Caucasian (r(2)=0.75; p<0.001) and Asian equation (r(2)=0.7; p<0.001). Despite this, the level of absolute agreement was poor, with large bias and wide limits of agreement. According to the Caucasian equation the mean difference between methods was -8.3 ± 3.9 (95% limits of agreement -20.10 to 9.40), for the Asian equations mean difference was -5.4 ± 4.3 (95% limits of agreement -20.63 to 11.41). When compared to DEXA, the current Asian and Caucasian Tanita formulae significantly under-estimate the %BF of Asian Indians. Copyright © 2013 Diabetes India. Published by Elsevier Ltd. All rights reserved.

  14. Validity of a new abdominal bioelectrical impedance device to measure abdominal and visceral fat: comparison with MRI.

    Science.gov (United States)

    Browning, Lucy M; Mugridge, Owen; Chatfield, Mark D; Dixon, Adrian K; Aitken, Sri W; Joubert, Ilse; Prentice, Andrew M; Jebb, Susan A

    2010-12-01

    Abdominal fat, and in particular, visceral adipose tissue (VAT), is the critical fat depot associated with metabolic aberrations. At present, VAT can only be accurately measured by computed tomography or magnetic resonance imaging (MRI). This study was designed to compare a new abdominal bioelectrical impedance (BIA) device against total abdominal adipose tissue (TAAT) and VAT area measurements made from an abdominal MRI scan, and to assess its reliability and accuracy. One-hundred twenty participants were recruited, stratified by gender and BMI. Participants had triplicate measures of abdominal fat and waist circumference (WC) with the AB-140 (Tanita, Tokyo, Japan) and WC measurements using a manual tape measure. A single abdominal MRI scan was performed as the reference method. Triplicate measures with the AB-140 showed excellent precision for "visceral fat level," trunk fat %, and WC. AB-140 "visceral fat level" showed significantly stronger correlations with MRI TAAT area than with MRI VAT area (r = 0.94 vs. 0.65 in men and 0.92 vs. 0.64 in women). AB-140 WC showed good correlation with manual WC measurements (r = 0.95 in men and 0.90 in women). AB-140 and manual WCs showed comparable correlations with MRI TAAT area (r = 0.92 and 0.96 in men and 0.88 and 0.88 in women). AB-140 is a simple, quick, and precise technique to measure abdominal fat and WC in healthy adults. It provides a useful proxy for TAAT measured by MRI, comparable to the correlation obtained with manual WC measurements. Neither the AB-140 abdominal fat measures nor WC measurement appear to provide a useful proxy measure of VAT.

  15. Validation of two portable bioelectrical impedance analyses for the assessment of body composition in school age children.

    Science.gov (United States)

    Lee, Li-Wen; Liao, Yu-San; Lu, Hsueh-Kuan; Hsiao, Pei-Lin; Chen, Yu-Yawn; Chi, Ching-Chi; Hsieh, Kuen-Chang

    2017-01-01

    Bioelectrical impedance analysis (BIA) is a convenient and child-friendly method for longitudinal analysis of changes in body composition. However, most validation studies of BIA have been performed on adult Caucasians. The present cross-sectional study investigated the validity of two portable BIA devices, the Inbody 230 (BIA8MF) and the Tanita BC-418 (BIA8SF), in healthy Taiwanese children. Children aged 7-12 years (72 boys and 78 girls) were recruited. Body composition was measured by the BIA8SF and the BIA8MF. Dual X-ray absorptiometry (DXA) was used as the reference method. There were strong linear correlations in body composition measurements between the BIA8SF and DXA and between the BIA8MF and DXA. Both BIAs underestimated fat mass (FM) and percentage body fat (%BF) relative to DXA in both genders The degree of agreement in lean body mass (LBM), FM, and %BF estimates was higher between BIA8MF and DXA than between BIA8SF and DXA. The Lin's concordance correlation coefficient (ρc) for LBM8MF met the criteria of substantial to perfect agreement whereas the ρc for FM8MF met the criteria of fair to substantial agreement. Bland-Altman analysis showed a clinically acceptable agreement between LBM measures by BIA8MF and DXA. The limit of agreement in %BF estimation by BIA and DXA were wide and the errors were clinically important. For the estimation of ALM, BIA8SF and BIA8MF both provided poor accuracy. For all children, LBM measures were precise and accurate using the BIA8MF whereas clinically significant errors occurred in FM and %BF estimates. Both BIAs underestimated FM and %BF in children. Thus, the body composition results obtained using the inbuilt equations of the BIA8SF and BIA8MF should be interpreted with caution, and high quality validation studies for specific subgroups of children are required prior to field research.

  16. Estimation of thigh muscle cross-sectional area by single- and multifrequency segmental bioelectrical impedance analysis in the elderly.

    Science.gov (United States)

    Yamada, Yosuke; Ikenaga, Masahiro; Takeda, Noriko; Morimura, Kazuhiro; Miyoshi, Nobuyuki; Kiyonaga, Akira; Kimura, Misaka; Higaki, Yasuki; Tanaka, Hiroaki

    2014-01-15

    Bioelectrical impedance analysis (BIA) has been used to estimate skeletal muscle mass, but its application in the elderly is not optimal. The accuracy of BIA may be influenced by the expansion of extracellular water (ECW) relative to muscle mass with aging. Multifrequency BIA (MFBIA) can evaluate the distribution between ECW and intracellular water (ICW), and thus may be superior to single-frequency BIA (SFBIA) to estimate muscle mass in the elderly. A total of 58 elderly participants aged 65-85 years were recruited. Muscle cross-sectional area (CSA) was obtained from computed tomography scans at the mid-thigh. Segmental SFBIA and MFBIA were measured for the upper legs. An index of the ratio of ECW and ICW was calculated using MFBIA. The correlation between muscle CSA and SFBIA was moderate (r = 0.68), but strong between muscle CSA and MFBIA (r = 0.85). ECW/ICW index was significantly and positively correlated with age (P < 0.001). SFBIA tends to significantly overestimate muscle CSA in subjects who had relative expansion of ECW in the thigh segment (P < 0.001). This trend was not observed for MFBIA (P = 0.42). Relative expansion of ECW was observed in older participants. The relative expansion of ECW affects the validity of traditional SFBIA, which is lowered when estimating muscle CSA in the elderly. By contrast, MFBIA was not affected by water distribution in thigh segments, thus rendering the validity of MFBIA for estimating thigh muscle CSA higher than SFBIA in the elderly.

  17. Comparison of Standing Posture Bioelectrical Impedance Analysis with DXA for Body Composition in a Large, Healthy Chinese Population

    Science.gov (United States)

    Chen, Kuen-Tsann; Chen, Yu-Yawn; Wang, Chia-Wei; Chuang, Chih-Lin; Chiang, Li-Ming; Lai, Chung-Liang; Lu, Hsueh-Kuan; Dwyer, Gregory B.; Chao, Shu-Ping; Shih, Ming-Kuei; Hsieh, Kuen-Chang

    2016-01-01

    Bioelectrical impedance analysis (BIA) is a common method for assessing body composition in research and clinical trials. BIA is convenient but when compared with other reference methods, the results have been inconclusive. The level of obesity degree in subjects is considered to be an important factor affecting the accuracy of the measurements. A total of 711 participants were recruited in Taiwan and were sub-grouped by gender and levels of adiposity. Regression analysis and Bland-Altman analysis were used to evaluate the agreement of the measured body fat percentage (BF%) between BIA and DXA. The BF% measured by the DXA and BIA methods (Tanita BC-418) were expressed as BF%DXA and BF%BIA8, respectively. A one-way ANOVA was used to test the differences in BF% measurements by gender and levels of adiposity. The estimated BF%BIA8 and BF%DXA in the all subjects, male and female groups were all highly correlated (r = 0.934, 0.901, 0.916, all P< 0.001). The average estimated BF%BIA8 (22.54 ± 9.48%) was significantly lower than the average BF%DXA (26.26 ± 11.18%). The BF%BIA8 was overestimated in the male subgroup (BF%DXA< 15%), compared to BF%DXA by 0.45%, respectively. In the other subgroups, the BF%BIA8 values were all underestimated. Standing BIA estimating body fat percentage in Chinese participants have a high correlation, but underestimated on normal and high obesity degree in both male and female subjects. PMID:27467065

  18. Prevalence of malnutrition and validation of bioelectrical impedance analysis for the assessment of body composition in patients with systemic sclerosis.

    Science.gov (United States)

    Spanjer, Moon J; Bultink, Irene E M; de van der Schueren, Marian A E; Voskuyl, Alexandre E

    2017-06-01

    The aims were to assess the prevalence of malnutrition and to validate bioelectrical impedance analysis (BIA) against whole-body DXA for the assessment of body composition in patients with SSc. Malnutrition was defined as BMI 10% in combination with a fat-free mass index (FFMI) 70 years). Body composition was assessed in 72 patients with whole-body DXA (Hologic, Discovery A) and BIA (Bodystat Quadscan 400). The manufacturer's equation and the Geneva equation were used to estimate FFM and fat mass. The agreement between BIA and whole-body DXA was assessed with Bland-Altman analysis and intraclass correlation coefficient. Malnutrition was found in 8.3% (n = 6) and low FFMI in 20.8% (n = 15) of patients. The mean difference in FFM between BIA and DXA applying the Geneva equation was 0.02 ( s . d . 2.4) kg, intraclass correlation coefficient 0.97 (95% CI: 0.95, 0.98). Limits of agreement were ±4.6 kg. The manufacturer's equation was less adequate to predict FFM. This study shows a relatively low prevalence of malnutrition in comparison with other studies, but a high prevalence of low FFMI, underlining the necessity of measuring body composition in SSc patients with a standardized and validated method. A good validity of BIA in determining FFM was found at a group level, while at an individual level the FFM may vary by 4.6 kg. © The Author 2017. Published by Oxford University Press on behalf of the British Society for Rheumatology. All rights reserved. For Permissions, please email: journals.permissions@oup.com

  19. A comparison of the malnutrition screening tools, MUST, MNA and bioelectrical impedance assessment in frail older hospital patients.

    Science.gov (United States)

    Slee, Adrian; Birch, Deborah; Stokoe, David

    2015-04-01

    This cohort study aimed to investigate and compare the ability to predict malnutrition in a group of frail older hospital patients in the United Kingdom using the nutritional risk screening tools, MUST (malnutrition universal screening tool), MNA-SF(®) (mini nutritional assessment-short form) and bioelectrical impedance assessment (BIA) of body composition. MUST and MNA-SF was performed on 78 patients (49 males and 29 females, age: 82 y ± 7.9, body mass index (BMI): 25.5 kg/m(2) ± 5.4), categorised by nutritional risk, and statistical comparison and test reliability performed. BIA was performed in 66 patients and fat free mass (FFM), fat mass (FM) and body cell mass (BCM) and index values (kg/m(2)) calculated and compared against reference values. MUST scored 77% patients 'low risk', 9% 'medium risk' and 14% 'high risk', compared to MNA-SF categorisation: 9%, 46% and 45%, respectively (P tools (coefficient, r = 0.4). Significant positive correlations were found between most variables (P males low/depleted, 21% borderline/at risk with 96% categorised by MNA-SF as either malnourished or at risk (MUST-35%). 29% males had low FM index and all appropriately classified by MNA-SF. 30% females had low FFM index or borderline, MNA-SF screening appropriately categorised 86% (compared to MUST-29%). This preliminary data may have significant clinical implications and highlights the potential ability of the MNA-SF and BIA to accurately assess malnutrition risk over MUST in frail older hospital patients. Copyright © 2014 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.

  20. Application of bioelectrical impedance analysis to assess rabbit's body composition from 25 to 77 days of age.

    Science.gov (United States)

    Saiz, A; García-Ruiz, A I; Fuentes-Pila, J; Nicodemus, N

    2017-06-01

    The aim of the study was to develop prediction equations for assessing, in vivo, the whole body composition of growing rabbits. The accuracy of the models obtained was externally validated with independent data sets. One hundred fifty rabbits grouped at 5 different ages (25, 35, 49, 63, and 77 d) were used. A body composition analyzer with 4 terminals was used to obtain resistance (Rs; Ω) and reactance (Xc; Ω) values. The distance between internal electrodes (D; cm), body length (Len; cm), and live BW (g) were also registered. Average values of Rs, Xc, impedance (Z), Len, D, and BW were 83.5 ± 23.1 Ω, 18.2 ± 3.8 Ω, 85.6 ± 22.9 Ω, 30.6 ± 6.9 cm, 10.8 ± 3.1 cm, and 1,454 ± 845 g, respectively. At each selected age, animals were slaughtered, ground, and frozen (-20°C) for determining water, fat, CP, ash, and GE (70.5 ± 3.36%, 27.7 ± 7.61% DM, 54.9 ± 5.41% DM, 11.1 ± 1.55% DM, and 2,267 ± 183 kJ/100 g DM, on average, respectively). Fat and GE contents increased with the age, whereas CP, ash, and water contents decreased. A multiple linear regression analysis was used to determine the prediction equations, using BW, Len, and Z data as independent variables. Equations obtained to estimate water (g), CP (g), fat (g), ash (g), and GE (MJ) had coefficient of determination () values of 0.99, 0.99, 0.97, 0.98, and 0.99, respectively, and the relative mean prediction error (RMPE) was 2.79, 6.15, 24.3, 15.2, and 10.6%, respectively. When water was expressed as a percentage, the and RMPE were 0.85 and 2.30%, respectively. When prediction of the content of protein (% DM), fat (% DM), ash (% DM), and energy (kJ/100 g DM) was done, values of 0.79, 0.83, 0.71, and 0.86, respectively, for and 5.04, 18.9, 12.0, and 3.19%, respectively, for RMPE were obtained. It could be concluded that bioelectrical impedance analysis is a good, noninvasive method to estimate, in vivo, whole body composition of growing rabbits from 25 to 77 d of age.

  1. Malnutrition in remission of childhood cancers as assessed by bioelectric impedance analysis

    Directory of Open Access Journals (Sweden)

    M. V. Konovalova

    2014-07-01

    Full Text Available The results of our cross-sectional bioimpedance study of children aged 7–17 years cured of cancer during follow-up (patients’ group, n = 552, remission time range 0–15 years and of age-matched healthy controls (n = 1,500 show significant intergroup differences in body height and body composition parameters. The most pronounced alterations in the patients’ group were observed in standardized values of phase angle reflecting a sharp decrease in the percentage of metabolically active body cell mass in fat-free mass. Malnutrition, judged from the prevalence of obesity and low phase angle, was observed in 52.7 % of our patients reaching a maximum of 76.8 % in a subgroup of children with CNS tumors. In view of known association that exists between malnutrition and reduced tolerance to chemotherapy, increased susceptibility to infections and adverse outcomes rate, we recommend using bioimpedance analysis in remission of childhood cancers in order to monitoring and timely correction of nutritional state as well as for prevention of delayed cardiovascular risks.

  2. Malnutrition in remission of childhood cancers as assessed by bioelectric impedance analysis

    Directory of Open Access Journals (Sweden)

    M. V. Konovalova

    2012-01-01

    Full Text Available The results of our cross-sectional bioimpedance study of children aged 7–17 years cured of cancer during follow-up (patients’ group, n = 552, remission time range 0–15 years and of age-matched healthy controls (n = 1,500 show significant intergroup differences in body height and body composition parameters. The most pronounced alterations in the patients’ group were observed in standardized values of phase angle reflecting a sharp decrease in the percentage of metabolically active body cell mass in fat-free mass. Malnutrition, judged from the prevalence of obesity and low phase angle, was observed in 52.7 % of our patients reaching a maximum of 76.8 % in a subgroup of children with CNS tumors. In view of known association that exists between malnutrition and reduced tolerance to chemotherapy, increased susceptibility to infections and adverse outcomes rate, we recommend using bioimpedance analysis in remission of childhood cancers in order to monitoring and timely correction of nutritional state as well as for prevention of delayed cardiovascular risks.

  3. Bioelectrical impedance and visceral fat: a comparison with computed tomography in adults and elderly

    International Nuclear Information System (INIS)

    Eickemberg, Michaela; Roriz, Anna Karla Carneiro; Fontes, Gardenia Abreu Vieira; Sampaio, Lilian Ramos

    2013-01-01

    Objective: To evaluate the association between electrical bioimpedance analysis (BIA) and visceral fat (VF) in adult and elderly patients. Subjects and methods: This was a cross-sectional study, with a sample of 191 subjects (52% women, 49% elderly) stratified by sex, age and body mass. Computerized tomography (VF area) and BIA (percentage of total body fat (%TBF-BIA), phase angle, reactance and resistance) data were generated. Statistical analysis was based on Pearson's Correlation Coefficient, Anova, Pearson's Chi-square, and ROC curves. Results: VF areas ≥ 130 cm 2 were more prevalent among the elderly and among men. Adult females showed a stronger correlation between GV and %TBF-BIA. The other groups showed similar results and statistically significant correlations. Correlations between GV and phase angle were weak and not statistically significant. ROC Curves analyzes showed the following %TBF-BIA, which identified excess VF: for male subjects: 21.5% (adults) and 24.25% (elderly); for female subjects: 35.05% (adults) and 38.45% (elderly) with sensitivity of 78.6%, 82.1%, 83.3%, and 66.7%, and specificity of 70.6%, 62.5%, 79.1%, and 69%, respectively. Conclusion: BIA was found to have satisfactory sensitivity and specificity to predict VF; however, other devices and other techniques should be investigated to improve VF prediction. (author)

  4. Foot-to-foot bioelectrical impedance accurately tracks direction of adiposity change in overweight and obese 7- to 13-year-old children.

    Science.gov (United States)

    Kasvis, Popi; Cohen, Tamara R; Loiselle, Sarah-Ève; Kim, Nicolas; Hazell, Tom J; Vanstone, Catherine A; Rodd, Celia; Plourde, Hugues; Weiler, Hope A

    2015-03-01

    Body composition measurements are valuable when evaluating pediatric obesity interventions. We hypothesized that foot-to-foot bioelectrical impedance analysis (BIA) will accurately track the direction of adiposity change, but not magnitude, in part due to differences in fat patterning. The purposes of this study were to examine the accuracy of body composition measurements of overweight and obese children over time using dual-energy x-ray absorptiometry (DXA) and BIA and to determine if BIA accuracy was affected by fat patterning. Eighty-nine overweight or obese children (48 girls, 41 boys, age 7-13 years) participating in a randomized controlled trial providing a family-centered, lifestyle intervention, underwent DXA and BIA measurements every 3 months. Bland-Altman plots showed a poor level of agreement between devices for baseline percent body fat (%BF; mean, 0.398%; +2SD, 8.685%; -2SD, -7.889%). There was overall agreement between DXA and BIA in the direction of change over time for %BF (difference between visits 3 and 1: DXA -0.8 ± 0.5%, BIA -0.7 ± 0.5%; P = 1.000) and fat mass (FM; difference between visits 3 and 1: DXA 0.7 ± 0.5 kg, BIA 0.6 ± 0.5 kg; P = 1.000). Bioelectrical impedance analysis measurements of %BF and FM at baseline were significantly different in those with android and gynoid fat (%BF: 35.9% ± 1.4%, 32.2% ± 1.4%, P Bioelectrical impedance analysis accurately reports the direction of change in FM and FFM in overweight and obese children; inaccuracy in the magnitude of BIA measurements may be a result of fat patterning differences. Copyright © 2015 Elsevier Inc. All rights reserved.

  5. Obesity in young-adult Nigerians: variations in prevalence determined by anthropometry and bioelectrical impedance analysis, and the development of % body fat prediction equations

    OpenAIRE

    Ejike, Chukwunonso ECC; Ijeh, Ifeoma I

    2012-01-01

    Abstract Background Overweight/obesity is a growing global public health concern. The variations in the prevalence of overweight/obesity, defined by Body Mass Index (BMI), Waist Circumference (WC), Waist-to-Height Ratio (WHtR), Waist-to-Hip Ratio (WHpR) and Bioelectrical Impedance Analysis (BIA), were studied and a prediction equation for % body fat (%BF) developed. Methods A total of 1584 subjects (56.4% males) were recruited for the study. Data on age, gender, height, weight, hip circumfere...

  6. Performance of Two Bioelectrical Impedance Analyses in the Diagnosis of Overweight and Obesity in Children and Adolescents: The FUPRECOL Study

    Science.gov (United States)

    Ramírez-Vélez, Robinson; Correa-Bautista, Jorge Enrique; Martínez-Torres, Javier; González-Ruíz, Katherine; González-Jiménez, Emilio; Schmidt-RioValle, Jacqueline; Garcia-Hermoso, Antonio

    2016-01-01

    This study aimed to determine thresholds for percentage of body fat (BF%) corresponding to the cut-off values for overweight/obesity as recommended by the International Obesity Task Force (IOTF), using two bioelectrical impedance analyzers (BIA), and described the likelihood of increased cardiometabolic risk in our cohort defined by the IOTF and BF% status. Participants included 1165 children and adolescents (54.9% girls) from Bogotá (Colombia). Body mass index (BMI) was calculated from height and weight. BF% of each youth was assessed first using the Tanita BC-418® followed by a Tanita BF-689®. The sensitivity and specificity of both devices and their ability to correctly classify children as overweight/obesity (≥2 standard deviation), as defined by IOTF, was investigated using receiver operating characteristic (ROC) by sex and age groups (9–11, 12–14, and 13–17 years old); Area under curve (AUC) values were also reported. For girls, the optimal BF% threshold for classifying into overweight/obesity was found to be between 25.2 and 28.5 (AUC = 0.91–0.97) and 23.9 to 26.6 (AUC = 0.90–0.99) for Tanita BC-418® and Tanita BF-689®, respectively. For boys, the optimal threshold was between 16.5 and 21.1 (AUC = 0.93–0.96) and 15.8 to 20.6 (AUC = 0.92–0.94) by Tanita BC-418® and Tanita BF-689®, respectively. All AUC values for ROC curves were statistically significant and there were no differences between AUC values measured by both BIA devices. The BF% values associated with the IOTF-recommended BMI cut-off for overweight/obesity may require age- and sex-specific threshold values in Colombian children and adolescents aged 9–17 years and could be used as a surrogate method to identify individuals at risk of excess adiposity. PMID:27782039

  7. Accuracy of Bioelectrical Impedance Analysis in Estimated Longitudinal Fat-Free Mass Changes in Male Army Cadets.

    Science.gov (United States)

    Langer, Raquel D; Matias, Catarina N; Borges, Juliano H; Cirolini, Vagner X; Páscoa, Mauro A; Guerra-Júnior, Gil; Gonçalves, Ezequiel M

    2018-03-26

    Bioelectrical impedance analysis (BIA) is a practical and rapid method for making a longitudinal analysis of changes in body composition. However, most BIA validation studies have been performed in a clinical population and only at one moment, or point in time (cross-sectional study). The aim of this study is to investigate the accuracy of predictive equations based on BIA with regard to the changes in fat-free mass (FFM) in Brazilian male army cadets after 7 mo of military training. The values used were determined using dual-energy X-ray absorptiometry (DXA) as a reference method. The study included 310 male Brazilian Army cadets (aged 17-24 yr). FFM was measured using eight general predictive BIA equations, with one equation specifically applied to this population sample, and the values were compared with results obtained using DXA. The student's t-test, adjusted coefficient of determination (R2), standard error of estimation (SEE), Lin's approach, and the Bland-Altman test were used to determine the accuracy of the predictive BIA equations used to estimate FFM in this population and between the two moments (pre- and post-moment). The FFM measured using the nine predictive BIA equations, and determined using DXA at the post-moment, showed a significant increase when compared with the pre-moment (p army cadets between the two moments in a very similar way to the reference method (DXA). However, only the one BIA equation specific to this population showed no significant differences in the FFM estimation between DXA at pre- and post-moment of military routine. All predictive BIA equations showed large limits of agreement using the Bland-Altman approach. The eight general predictive BIA equations used in this study were not found to be valid for analyzing the FFM changes in the Brazilian male army cadets, after a period of approximately 7 mo of military training. Although the BIA equation specific to this population is dependent on the amount of FFM, it appears to be

  8. Performance of Two Bioelectrical Impedance Analyses in the Diagnosis of Overweight and Obesity in Children and Adolescents: The FUPRECOL Study

    Directory of Open Access Journals (Sweden)

    Robinson Ramírez-Vélez

    2016-10-01

    Full Text Available This study aimed to determine thresholds for percentage of body fat (BF% corresponding to the cut-off values for overweight/obesity as recommended by the International Obesity Task Force (IOTF, using two bioelectrical impedance analyzers (BIA, and described the likelihood of increased cardiometabolic risk in our cohort defined by the IOTF and BF% status. Participants included 1165 children and adolescents (54.9% girls from Bogotá (Colombia. Body mass index (BMI was calculated from height and weight. BF% of each youth was assessed first using the Tanita BC-418® followed by a Tanita BF-689®. The sensitivity and specificity of both devices and their ability to correctly classify children as overweight/obesity (≥2 standard deviation, as defined by IOTF, was investigated using receiver operating characteristic (ROC by sex and age groups (9–11, 12–14, and 13–17 years old; Area under curve (AUC values were also reported. For girls, the optimal BF% threshold for classifying into overweight/obesity was found to be between 25.2 and 28.5 (AUC = 0.91–0.97 and 23.9 to 26.6 (AUC = 0.90–0.99 for Tanita BC-418® and Tanita BF-689®, respectively. For boys, the optimal threshold was between 16.5 and 21.1 (AUC = 0.93–0.96 and 15.8 to 20.6 (AUC = 0.92–0.94 by Tanita BC-418® and Tanita BF-689®, respectively. All AUC values for ROC curves were statistically significant and there were no differences between AUC values measured by both BIA devices. The BF% values associated with the IOTF-recommended BMI cut-off for overweight/obesity may require age- and sex-specific threshold values in Colombian children and adolescents aged 9–17 years and could be used as a surrogate method to identify individuals at risk of excess adiposity.

  9. Validation study of multi-frequency bioelectrical impedance with dual-energy X-ray absorptiometry among obese patients.

    Science.gov (United States)

    Faria, Silvia L; Faria, Orlando P; Cardeal, Mariane D A; Ito, Marina Kiyomi

    2014-09-01

    Body mass index (BMI) is the most common parameter for classifying nutritional status. However, body composition (BC) may vary considerably among individuals with identical BMIs; consequently, we need to assess BC efficiently. Bariatric surgery is the most effective method for treating obesity. To improve quality assessment of postoperative weight loss, it is essential to assess BC. Multi-frequency bioelectrical impedance analysis (BIA) is a practical assessment instrument, though limited when applied among the obese population. Despite dual-energy X-ray absorptiometry (DXA) being the current reference standard, it has physical limitations which restrict its practical application. This study, therefore, sought to correlate the results of BC assessments of same patient population using BIA and DXA. This was a cross-sectional validation study with patients invited to undergo a multi-frequency BIA (Inbody 720®) and afterwards a DXA examination Statistical analyses were done using the intraclass correlation coefficient (ICC), paired t-test and the Bland-Altman plot analysis. A total of 108 patients were randomly selected, with 73 meeting the criteria for study inclusion. Most were female (89%) and had an average BMI of 40.17 ± 4.08 kg/m(2). An almost perfect correlation of fat (kg) and fat-free mass (kg) was found in results from the BIA and DXA examination (ICC = 0.832 and ICC = 0.899, respectively). A substantial correlation was also found between the percentage of body fat (%BF) and the percentage of fat-free mass (%FFM). The comparison made between the BIA and DXA using the t-test showed significant differences between all parameters. The Bland-Altman plot showed that the BIA method tends to underestimate the FM and overestimate the LM measurements when compared with DXA. BIA proved to be a safe alternative for assessing BC in clinically severely obese patients and thus provides a more accessible evaluation tool for this population. But, consideration

  10. Comparison between bioelectrical impedance analysis and body mass index methods in determination of obesity prevalence in Ahvazi women.

    Science.gov (United States)

    Amani, R

    2007-04-01

    Obesity has an increasing trend worldwide. Recently, application of body mass index (BMI) cutoff points of obesity classification for all population studies has been questioned. On the other hand, bioelectrical impedance analysis (BIA) is a safe, accurate, reliable and inexpensive method for screening the overweight and obesity in such studies. There were three objectives followed in this research: to determine the prevalence of obesity and overweight in married women using BMI and BIA methods; to evaluate the correlation between these methods; and to compare the women's obesity degrees according to their educational levels. Six hundred and thirty-seven healthy married women 18-40 years aged, who had referred to 14 health centers of the city of Ahvaz (center of Khouzestan province, south-west of Iran) were recruited in a cross-sectional design, and their socio-economic and anthropometric questionnaires were completed by the trained students. Body fat percent (%BF) and body fat mass (BFM) were measured using BIA method. BMI>25 and >30 kg/m(2) were used as criteria for determining the overweight and obese women, respectively. %BF>35% was regarded as cutoff for defining obesity. Mean age+/-s.d. of the women was 26.9+/-5.8 years and majority of them were housewives with secondary educational level. Their BMI, %BF, waist-to-hip ratio, and mid-upper arm circumference means were: 25.9(4.7) kg/m(2), 27.6(7.3)%, 0.75(0.08) and 27.9(3.9) cm, respectively. Central obesity was prevalent in 21.2% of the subjects. Prevalence of obesity determined by BMI and BIA methods was 18.3 and 15.5% and women within normal ranges were detected in 44.7 and 46% of the subjects by these methods, respectively. However, thin (underweight) women were 2.6 and 14.6% of the subjects studied, respectively. About one half of the women were overweight or obese. BMI was statistically correlated with BFM (r=0.86; PObesity and overweight is prevalent in about one-half of the Ahvazian married women and

  11. Performance of Two Bioelectrical Impedance Analyses in the Diagnosis of Overweight and Obesity in Children and Adolescents: The FUPRECOL Study.

    Science.gov (United States)

    Ramírez-Vélez, Robinson; Correa-Bautista, Jorge Enrique; Martínez-Torres, Javier; González-Ruíz, Katherine; González-Jiménez, Emilio; Schmidt-RioValle, Jacqueline; Garcia-Hermoso, Antonio

    2016-10-04

    This study aimed to determine thresholds for percentage of body fat (BF%) corresponding to the cut-off values for overweight/obesity as recommended by the International Obesity Task Force (IOTF), using two bioelectrical impedance analyzers (BIA), and described the likelihood of increased cardiometabolic risk in our cohort defined by the IOTF and BF% status. Participants included 1165 children and adolescents (54.9% girls) from Bogotá (Colombia). Body mass index (BMI) was calculated from height and weight. BF% of each youth was assessed first using the Tanita BC-418® followed by a Tanita BF-689®. The sensitivity and specificity of both devices and their ability to correctly classify children as overweight/obesity (≥2 standard deviation), as defined by IOTF, was investigated using receiver operating characteristic (ROC) by sex and age groups (9-11, 12-14, and 13-17 years old); Area under curve (AUC) values were also reported. For girls, the optimal BF% threshold for classifying into overweight/obesity was found to be between 25.2 and 28.5 (AUC = 0.91-0.97) and 23.9 to 26.6 (AUC = 0.90-0.99) for Tanita BC-418® and Tanita BF-689®, respectively. For boys, the optimal threshold was between 16.5 and 21.1 (AUC = 0.93-0.96) and 15.8 to 20.6 (AUC = 0.92-0.94) by Tanita BC-418® and Tanita BF-689®, respectively. All AUC values for ROC curves were statistically significant and there were no differences between AUC values measured by both BIA devices. The BF% values associated with the IOTF-recommended BMI cut-off for overweight/obesity may require age- and sex-specific threshold values in Colombian children and adolescents aged 9-17 years and could be used as a surrogate method to identify individuals at risk of excess adiposity.

  12. Hand-to-Hand Model for Bioelectrical Impedance Analysis to Estimate Fat Free Mass in a Healthy Population

    Directory of Open Access Journals (Sweden)

    Hsueh-Kuan Lu

    2016-10-01

    Full Text Available This study aimed to establish a hand-to-hand (HH model for bioelectrical impedance analysis (BIA fat free mass (FFM estimation by comparing with a standing position hand-to-foot (HF BIA model and dual energy X-ray absorptiometry (DXA; we also verified the reliability of the newly developed model. A total of 704 healthy Chinese individuals (403 men and 301 women participated. FFM (FFMDXA reference variables were measured using DXA and segmental BIA. Further, regression analysis, Bland–Altman plots, and cross-validation (2/3 participants as the modeling group, 1/3 as the validation group; three turns were repeated for validation grouping were conducted to compare tests of agreement with FFMDXA reference variables. In male participants, the hand-to-hand BIA model estimation equation was calculated as follows: FFMmHH = 0.537 h2/ZHH − 0.126 year + 0.217 weight + 18.235 (r2 = 0.919, standard estimate of error (SEE = 2.164 kg, n = 269. The mean validated correlation coefficients and limits of agreement (LOAs of the Bland–Altman analysis of the calculated values for FFMmHH and FFMDXA were 0.958 and −4.369–4.343 kg, respectively, for hand-to-foot BIA model measurements for men; the FFM (FFMmHF and FFMDXA were 0.958 and −4.356–4.375 kg, respectively. The hand-to-hand BIA model estimating equation for female participants was FFMFHH = 0.615 h2/ZHH − 0.144 year + 0.132 weight + 16.507 (r2 = 0.870, SEE = 1.884 kg, n = 201; the three mean validated correlation coefficient and LOA for the hand-to-foot BIA model measurements for female participants (FFMFHH and FFMDXA were 0.929 and −3.880–3.886 kg, respectively. The FFMHF and FFMDXA were 0.942 and −3.511–3.489 kg, respectively. The results of both hand-to-hand and hand-to-foot BIA models demonstrated similar reliability, and the hand-to-hand BIA models are practical for assessing FFM.

  13. Validation of two portable bioelectrical impedance analyses for the assessment of body composition in school age children.

    Directory of Open Access Journals (Sweden)

    Li-Wen Lee

    Full Text Available Bioelectrical impedance analysis (BIA is a convenient and child-friendly method for longitudinal analysis of changes in body composition. However, most validation studies of BIA have been performed on adult Caucasians. The present cross-sectional study investigated the validity of two portable BIA devices, the Inbody 230 (BIA8MF and the Tanita BC-418 (BIA8SF, in healthy Taiwanese children.Children aged 7-12 years (72 boys and 78 girls were recruited. Body composition was measured by the BIA8SF and the BIA8MF. Dual X-ray absorptiometry (DXA was used as the reference method.There were strong linear correlations in body composition measurements between the BIA8SF and DXA and between the BIA8MF and DXA. Both BIAs underestimated fat mass (FM and percentage body fat (%BF relative to DXA in both genders The degree of agreement in lean body mass (LBM, FM, and %BF estimates was higher between BIA8MF and DXA than between BIA8SF and DXA. The Lin's concordance correlation coefficient (ρc for LBM8MF met the criteria of substantial to perfect agreement whereas the ρc for FM8MF met the criteria of fair to substantial agreement. Bland-Altman analysis showed a clinically acceptable agreement between LBM measures by BIA8MF and DXA. The limit of agreement in %BF estimation by BIA and DXA were wide and the errors were clinically important. For the estimation of ALM, BIA8SF and BIA8MF both provided poor accuracy.For all children, LBM measures were precise and accurate using the BIA8MF whereas clinically significant errors occurred in FM and %BF estimates. Both BIAs underestimated FM and %BF in children. Thus, the body composition results obtained using the inbuilt equations of the BIA8SF and BIA8MF should be interpreted with caution, and high quality validation studies for specific subgroups of children are required prior to field research.

  14. Hand-to-Hand Model for Bioelectrical Impedance Analysis to Estimate Fat Free Mass in a Healthy Population

    Science.gov (United States)

    Lu, Hsueh-Kuan; Chiang, Li-Ming; Chen, Yu-Yawn; Chuang, Chih-Lin; Chen, Kuen-Tsann; Dwyer, Gregory B.; Hsu, Ying-Lin; Chen, Chun-Hao; Hsieh, Kuen-Chang

    2016-01-01

    This study aimed to establish a hand-to-hand (HH) model for bioelectrical impedance analysis (BIA) fat free mass (FFM) estimation by comparing with a standing position hand-to-foot (HF) BIA model and dual energy X-ray absorptiometry (DXA); we also verified the reliability of the newly developed model. A total of 704 healthy Chinese individuals (403 men and 301 women) participated. FFM (FFMDXA) reference variables were measured using DXA and segmental BIA. Further, regression analysis, Bland–Altman plots, and cross-validation (2/3 participants as the modeling group, 1/3 as the validation group; three turns were repeated for validation grouping) were conducted to compare tests of agreement with FFMDXA reference variables. In male participants, the hand-to-hand BIA model estimation equation was calculated as follows: FFMmHH = 0.537 h2/ZHH − 0.126 year + 0.217 weight + 18.235 (r2 = 0.919, standard estimate of error (SEE) = 2.164 kg, n = 269). The mean validated correlation coefficients and limits of agreement (LOAs) of the Bland–Altman analysis of the calculated values for FFMmHH and FFMDXA were 0.958 and −4.369–4.343 kg, respectively, for hand-to-foot BIA model measurements for men; the FFM (FFMmHF) and FFMDXA were 0.958 and −4.356–4.375 kg, respectively. The hand-to-hand BIA model estimating equation for female participants was FFMFHH = 0.615 h2/ZHH − 0.144 year + 0.132 weight + 16.507 (r2 = 0.870, SEE = 1.884 kg, n = 201); the three mean validated correlation coefficient and LOA for the hand-to-foot BIA model measurements for female participants (FFMFHH and FFMDXA) were 0.929 and −3.880–3.886 kg, respectively. The FFMHF and FFMDXA were 0.942 and −3.511–3.489 kg, respectively. The results of both hand-to-hand and hand-to-foot BIA models demonstrated similar reliability, and the hand-to-hand BIA models are practical for assessing FFM. PMID:27775642

  15. Measurement of Phase Dependent Impedance for 3-phase Diode Rectifier

    DEFF Research Database (Denmark)

    Kwon, Jun Bum; Wang, Xiongfei; Bak, Claus Leth

    2016-01-01

    This paper presents a new method to measure the phase dependent impedance from an experimental set up. Though most of power electronics based system is gradually migrating to IGBT based voltage source converter due to their controllability, the rectifier composed of diode or thyristor components...

  16. Predicting appendicular lean and fat mass with bioelectrical impedance analysis in older adults with physical function decline - The PROVIDE study.

    Science.gov (United States)

    Scafoglieri, Aldo; Clarys, Jan Pieter; Bauer, Jürgen M; Verlaan, Sjors; Van Malderen, Lien; Vantieghem, Stijn; Cederholm, Tommy; Sieber, Cornel C; Mets, Tony; Bautmans, Ivan

    2017-06-01

    No generalizable formulas exist that are derived from bioelectrical impedance analysis (BIA) for predicting appendicular lean mass (ALM) and fat mass (AFM) in sarcopenic older adults. Since precision of regional body composition (BC) data in multicentre trials is essential, this study aimed to: 1) develop and cross-validate soft tissue BIA equations with GE Lunar and Hologic DXA systems as their reference 2) to compare our new ALM equation to two previously published models and 3) to assess the agreement between BIA- and DXA-derived soft tissue ratios as indicators of limb tissue quality. Two-hundred and ninety-one participants with functional limitations (SPPB-score 4-9; sarcopenia class I or II, measured by BIA) were recruited from 18 study centres in six European countries. BIA equations, using DXA-derived ALM and AFM as the dependent variable, and age, gender, weight, impedance index and reactance as independent variables, were developed using a stepwise multiple linear regression approach. Cross-validation gave rise to 4 equations using the whole sample: ALM LUNAR (kg) = 1.821 + (0.168*height 2 /resistance) + (0.132*weight) + (0.017*reactance) - (1.931*sex) [R 2  = 0.86 and SEE = 1.37 kg] AFM LUNAR (kg) = -6.553 - (0.093* height 2 /resistance) + (0.272*weight) + (4.295*sex) [R 2  = 0.70 and SEE = 1.53 kg] ALM HOLOGIC (kg) = 4.957 + (0.196* height 2 /resistance) + (0.060*weight) - (2.554*sex) [R 2  = 0.90 and SEE = 1.28 kg] AFM HOLOGIC (kg) = -4.716 - (0.142* height 2 /resistance) + (0.316*weight) + (4.453*sex) - (0.040*reactance) [R 2  = 0.73 and SEE = 1.54 kg] Both previously published models significantly overestimated ALM in our sample with biases of -0.36 kg to -1.05 kg. For the ratio of ALM to AFM, a strong correlation (r = 0.82, P Hologic and Lunar reference values for BC. Previously published BIA-based models tend to overestimate ALM in sarcopenic older adults. Users of both GE Lunar and

  17. Bioelectrical impedance vectorial analysis and nutritional status of older women according. 10.5007/1980-0037.2011v13n6p415

    Directory of Open Access Journals (Sweden)

    Sandra Maria Lima Ribeiro

    2011-11-01

    Full Text Available The objective of the present study was to compare and discuss the nutritional status of older women according to different categories of BMI. Additionally, the study was aimed at introducing the bioelectrical impedance vector analysis (BIVA as a tool to assess the nutritional status. Thirty-two women (60 years or older, physically independent, and with moderate level of physical activity were divided into three groups according toBMI classification: G1 (BMI28 Kg/ m2. The following variables were analyzed as indicators of nutritional status: body mass and height to calculate BMI, waist circumference (WC, hip circumference (HC, waisthipratio (WHR, bioelectrical impedance (BIVA, resting energy expenditure (REE, biochemical markers of nutritional status (glucose, total cholesterol, and fractions, IGF-1, and leptin. The groups were compared using ANOVA and the Hotelling’s T 2 test for vector analysis. The main findings based on vector displacement showed lower reactance and higher resistance in G1. G3 showed the highest values of CC and leptin, and also lower REE. Therefore, higher BMI suggested at the same time higher cell mass and higher risk of developing chronic diseases. In turn, lower BMI values suggested reduced fat-free body mass. These results confirm the search for specific classification of BMI for the elderly and suggest the BIVA as a viable alternative in physical and nutritional assessment.

  18. Comparison of foot-to-foot and hand-to-foot bioelectrical impedance methods in a population with a wide range of body mass indices.

    Science.gov (United States)

    Gagnon, Claudia; Ménard, Julie; Bourbonnais, Annie; Ardilouze, Jean-Luc; Baillargeon, Jean-Patrice; Carpentier, André C; Langlois, Marie-France

    2010-10-01

    Several techniques are currently used for measurement of body composition. Bioelectrical impedance assessment (BIA) is a simple, noninvasive method of assessing body composition. We aimed to compare multifrequency hand-to-foot (HF-BIA) and foot-to-foot (FF-BIA) bioelectrical impedance analysis techniques to assess fat-free mass (FFM) in a population with a wide range of body mass indices (BMI). This was a cross-sectional study of 198 adult subjects. Anthropometric and BIA measures (HF-BIA with Hydra ICF/ECF, Xitron Technologies and FF-BIA with Tanita, model TBF-300A) were recorded after a 12-h fast. Participants had a mean age of 42 years and BMI of 33.50.7 (range, 17.7-65.6) kg/m2. Mean FFM with HF-BIA (FFM BIA/HF) and FF-BIA (FFM BIA/FF) were 61.31.3 kg and 58.10.9 kg, respectively (P 42 kg/m2 (-8.0 kg; P=0.001). Pearson correlations between both methods were very high for FFM (r=0.92), fat mass (r=0.91), and % fat mass (r=0.85), all Pobese subjects.

  19. Comparing measures of fat-free mass in overweight older adults using three different bioelectrical impedance devices and three prediction equations.

    Science.gov (United States)

    Ramsey, R; Isenring, E; Daniels, L

    2012-01-01

    To compare measures of fat-free mass (FFM) by three different bioelectrical impedance analysis (BIA) devices and to assess the agreement between three different equations validated in older adult and/or overweight populations. Cross-sectional study. Orthopaedics ward of Brisbane public hospital, Australia. Twenty-two overweight, older Australians (72 yr ± 6.4, BMI 34 kg/m² ± 5.5) with knee osteoarthritis. Body composition was measured using three BIA devices: Tanita 300-GS (foot-to-foot), Impedimed DF50 (hand-to-foot) and Impedimed SFB7 (bioelectrical impedance spectroscopy (BIS)). Three equations for predicting FFM were selected based on their ability to be applied to an older adult and/ or overweight population. Impedance values were extracted from the hand-to-foot BIA device and included in the equations to estimate FFM. The mean FFM measured by BIS (57.6 kg ± 9.1) differed significantly from those measured by foot-to-foot (54.6 kg ± 8.7) and hand-to-foot BIA (53.2 kg ± 10.5) (P equations using raw data from hand-to-foot BIA were 54.7 kg ± 8.9, 54.7 kg ± 7.9 and 52.9 kg ± 11.05 respectively. These results did not differ from the FFM predicted by the hand-to-foot device (F = 2.66, P = 0.118). Our results suggest that foot-to-foot and hand-to-foot BIA may be used interchangeably in overweight older adults at the group level but due to the large limits of agreement may lead to unacceptable error in individuals. There was no difference between the three prediction equations however these results should be confirmed within a larger sample and against a reference standard.

  20. Quantitative analysis of skeletal muscle mass in patients with rheumatic diseases under glucocorticoid therapy--comparison among bioelectrical impedance analysis, computed tomography, and magnetic resonance imaging.

    Science.gov (United States)

    Hosono, Osamu; Yoshikawa, Noritada; Shimizu, Noriaki; Kiryu, Shigeru; Uehara, Masaaki; Kobayashi, Hiroshi; Matsumiya, Ryo; Kuribara, Akiko; Maruyama, Takako; Tanaka, Hirotoshi

    2015-03-01

    To determine the availability of bioelectrical impedance analysis (BIA), computed tomography (CT), and magnetic resonance imaging (MRI) for measurement of skeletal muscle mass in patients with rheumatic diseases and quantitatively assess skeletal muscle loss after glucocorticoid (GC) treatment. The data from 22 patients with rheumatic diseases were retrospectively obtained. The muscle mass of body segments was measured with a BIA device in terms of skeletal muscle mass index (SMI). Cross-sectional area (CSA) was obtained from CT and MRI scans at the mid-thigh level using the image analysis program. We further assessed the data of three different measurements before and after GC treatment in 7 patients with rheumatic diseases. SMI of whole body was significantly correlated with estimated muscle volume and mid-thigh muscle CSA with CT and MRI (p rheumatic diseases, and CT and MRI appeared to be more accurate than BIA.

  1. Relationship between Body Mass Index (BMI) and body fat percentage, estimated by bioelectrical impedance, in a group of Sri Lankan adults: a cross sectional study.

    Science.gov (United States)

    Ranasinghe, Chathuranga; Gamage, Prasanna; Katulanda, Prasad; Andraweera, Nalinda; Thilakarathne, Sithira; Tharanga, Praveen

    2013-09-03

    Body Mass Index (BMI) is used as a useful population-level measure of overweight and obesity. It is used as the same for both sexes and for all ages of adults. The relationship between BMI and body fat percentage (BF %) has been studied in various ethnic groups to estimate the capacity of BMI to predict adiposity. We aimed to study the BMI-BF% relationship, in a group of South Asian adults who have a different body composition compared to presently studied ethnic groups. We examined the influence of age, gender in this relationship and assessed its' linearity or curvilinearity. A cross sectional study was conducted, where adults of 18-83 years were grouped into young (18-39 years) middle aged (40-59 years) and elderly (>60 years). BF% was estimated from bioelectrical impedance analysis. Pearsons' correlation coefficient(r) was calculated to see the relationship between BMI-BF% in the different age groups. Multiple regression analysis was performed to determine the effect of age and gender in the relationship and polynomial regression was carried out to see its' linearity. The relationships between age-BMI, age-BF % were separately assessed. Out of 1114 participants, 49.1% were males. The study sample represented a wide range of BMI values (14.8-41.1 kg/m2,Mean 23.8 ± 4.2 kg/m2). A significant positive correlation was observed between BMI-BF%, in males (r =0.75, p bioelectrical impedance, in this sub population of South Asian adults. This relationship was curvilinear in nature and was significantly influenced by age and gender. Our findings support the importance of taking age and gender in to consideration when using BMI to predict body fat percentage/obesity, in a population.

  2. Body composition analysis by leg-to-leg bioelectrical impedance and dual-energy X-ray absorptiometry in non-obese and obese individuals.

    Science.gov (United States)

    Boneva-Asiova, Z; Boyanov, M A

    2008-11-01

    The aim of this study is to compare total weight, % body fat (% BF), fat mass (FM) and fat-free mass (FFM) measured by bioelectrical impedance analysis (BIA) and dual-energy X-ray absorptiometry (DXA). This cross-sectional study included 159 women (mean age: 49.1 +/- 10.0 years) and 124 men (mean age: 51.4 +/- 8.0 years) subdivided according to sex and body mass index (BMI): BMI or = 35 kg/m(2) (40 women and 30 men). Bioelectrical impedance was performed in the fasting state on a Tanita TBF-215 leg-to-leg analyser (Tanita, Tokyo, Japan). Whole-body DXA scans were performed on a Hologic QDR 4500 A bone densitometer (Hologic, Bedford, MA, USA). Total weight, % BF, FM and FFM were tested for intermethod differences. Linear regression and correlation analysis was performed. Limits of agreement and Bland-Altman plots were built. DXA-derived body composition parameters were not significantly different from BIA estimates and were highly correlated (e.g. for FFM, r = 0.82-0.95). In lean individuals, BIA tended to produce lower values for FM and % BF and higher ones for FFM in comparison with DXA. This trend was reversed at BMI > 35 kg/m(2). The correlations decreased with increasing BMI. The limits of agreement were much better in men than in women and increased with increasing BMI in both sexes. Compared with DXA, the leg-to-leg Tanita TBF-215 analyser accurately assessed body composition in a heterogeneous group of both sexes. In the very obese women (BMI > 35 kg/m(2)), BIA measurements should be viewed with caution.

  3. Nutrition Status Parameters and Hydration Status by Bioelectrical Impedance Vector Analysis Were Associated With Lung Function Impairment in Children and Adolescents With Cystic Fibrosis.

    Science.gov (United States)

    Hauschild, Daniela Barbieri; Barbosa, Eliana; Moreira, Emilia Addison Machado; Ludwig Neto, Norberto; Platt, Vanessa Borges; Piacentini Filho, Eduardo; Wazlawik, Elisabeth; Moreno, Yara Maria Franco

    2016-06-01

    (1) To compare nutrition and hydration status between a group of children/adolescents with cystic fibrosis (CFG; n = 46; median age, 8.5 years) and a control group without cystic fibrosis (CG). (2) To examine the association of nutrition and hydration status with lung function in the CFG. A cross-sectional study. Nutrition screening, anthropometric parameters, and bioelectrical impedance analysis (BIA) were assessed. The z scores for body mass index for age, height for age, mid upper arm circumference, triceps and subscapular skinfold thickness, mid upper arm muscle area, resistance/height, and reactance/height were calculated. Bioelectrical impedance vector analysis was conducted. Forced expiratory volume in 1 second <80% was considered lung function impairment. An adjusted logistic regression was applied (P < .05). In the CFG, lung function impairment was observed in 51.1%. All anthropometric parameters were lower, and the mean z-resistance/height and z-reactance/height were higher in the CFG (P < .05) compared with the CG. In the CFG, 43% were severely/mildly dehydrated, while none were in the CG (P = .007). In the CFG, there was an association between high nutrition risk-via nutrition screening (odds ratio [OR], 22.28; P < .05), lower values of anthropometric parameters, higher z-resistance/height (OR, 2.23; P < .05) and z-reactance/height (OR, 1.81; P < .05), and dehydration (OR, 4.94; P < .05)-and lung function impairment. The CFG exhibited a compromised nutrition status assessed by anthropometric and BIA parameters. Nutrition screening, anthropometric and BIA parameters, and hydration status were associated with lung function. © 2016 American Society for Parenteral and Enteral Nutrition.

  4. Measurement and Evaluation of the Bioelectrical Impedance of the Human Body by Deconvolution of a Square Wave

    Science.gov (United States)

    Tseng, Yuhwai; Su, Chauchin; Liu, Chien-Nan Jimmy

    In this study, we use the deconvolution of a square test stimulus to replace a series of sinusoidal test waveforms with different frequencies to simplify the measurement of human body impedance. The average biological impedance of body parts is evaluated by constructing a frequency response of the equivalent human body system. Only two stainless-steel electrodes are employed in the measurement and evaluation.

  5. Evaluation of bioelectrical impedance analysis (BIA) to measure condition and energy allocated to reproduction in marine fishes

    Science.gov (United States)

    Fitzhugh, G. R.; Wuenschel, M. J.; McBride, R. S.

    2010-04-01

    Reliable estimates of fish energy density at specific times prior to spawning may provide suitable proxies for egg production, and thereby help to explain some of the observed annual variation in recruits per spawner. Our goal is to develop and test modifications of BIA technology to measure energy allocation to reproduction for a variety of marine fishes. To date, a newly developed measuring board and probe system stabilized readings, which was demonstrated by a significant reduction in the coefficients of variation for impedance measures. Total body water, wet and dry weights could be predicted with very good precision (r2 = 0.92-0.99) using BIA measures of reactance or resistance for a number of finfish species. While constituent relationships (e.g. body water- body mass functions) did not differ seasonally, we did find that BIA measures are sensitive to body composition changes related to the seasonal spawning cycle. In an examination of monthly samples of tilefish, phase angle decreased below 15° in post-spawning (regressed) females. Such a monthly trend, which suggests available energy had decreased following the spawning season, was not evident from other, more traditional measures of condition including body-muscle water content, Fulton's K or ordinal measures of fat deposition (such as mesenteric fat). These preliminary results show that BIA technology is a promising application for tracking and efficiently predicting energetic condition of marine fishes.

  6. Wearable Multi-Frequency and Multi-Segment Bioelectrical Impedance Spectroscopy for Unobtrusively Tracking Body Fluid Shifts during Physical Activity in Real-Field Applications: A Preliminary Study

    Directory of Open Access Journals (Sweden)

    Federica Villa

    2016-05-01

    Full Text Available Bioelectrical Impedance Spectroscopy (BIS allows assessing the composition of body districts noninvasively and quickly, potentially providing important physiological/clinical information. However, neither portable commercial instruments nor more advanced wearable prototypes simultaneously satisfy the demanding needs of unobtrusively tracking body fluid shifts in different segments simultaneously, over a broad frequency range, for long periods and with high measurements rate. These needs are often required to evaluate exercise tests in sports or rehabilitation medicine, or to assess gravitational stresses in aerospace medicine. Therefore, the aim of this work is to present a new wearable prototype for monitoring multi-segment and multi-frequency BIS unobtrusively over long periods. Our prototype guarantees low weight, small size and low power consumption. An analog board with current-injecting and voltage-sensing electrodes across three body segments interfaces a digital board that generates square-wave current stimuli and computes impedance at 10 frequencies from 1 to 796 kHz. To evaluate the information derivable from our device, we monitored the BIS of three body segments in a volunteer before, during and after physical exercise and postural shift. We show that it can describe the dynamics of exercise-induced changes and the effect of a sit-to-stand maneuver in active and inactive muscular districts separately and simultaneously.

  7. Prediction of fat-free mass and percentage of body fat in neonates using bioelectrical impedance analysis and anthropometric measures: validation against the PEA POD.

    Science.gov (United States)

    Lingwood, Barbara E; Storm van Leeuwen, Anne-Martine; Carberry, Angela E; Fitzgerald, Erin C; Callaway, Leonie K; Colditz, Paul B; Ward, Leigh C

    2012-05-01

    Accurate assessment of neonatal body composition is essential to studies investigating neonatal nutrition or developmental origins of obesity. Bioelectrical impedance analysis or bioimpedance analysis is inexpensive, non-invasive and portable, and is widely used in adults for the assessment of body composition. There are currently no prediction algorithms using bioimpedance analysis in neonates that have been directly validated against measurements of fat-free mass (FFM). The aim of the study was to evaluate the use of bioimpedance analysis for the estimation of FFM and percentage of body fat over the first 4 months of life in healthy infants born at term, and to compare these with estimations based on anthropometric measurements (weight and length) and with skinfolds. The present study was an observational study in seventy-seven infants. Body fat content of infants was assessed at birth, 6 weeks, 3 and 4·5 months of age by air displacement plethysmography, using the PEA POD body composition system. Bioimpedance analysis was performed at the same time and the data were used to develop and test prediction equations for FFM. The combination of weight+sex+length predicted FFM, with a bias of impedance in prediction algorithms resulted in small improvements in prediction of FFM, reducing the bias to < 50 g and limits of agreement to < 9 %. Skinfold measurements performed poorly at all ages.

  8. Wearable Multi-Frequency and Multi-Segment Bioelectrical Impedance Spectroscopy for Unobtrusively Tracking Body Fluid Shifts during Physical Activity in Real-Field Applications: A Preliminary Study

    Science.gov (United States)

    Villa, Federica; Magnani, Alessandro; Maggioni, Martina A.; Stahn, Alexander; Rampichini, Susanna; Merati, Giampiero; Castiglioni, Paolo

    2016-01-01

    Bioelectrical Impedance Spectroscopy (BIS) allows assessing the composition of body districts noninvasively and quickly, potentially providing important physiological/clinical information. However, neither portable commercial instruments nor more advanced wearable prototypes simultaneously satisfy the demanding needs of unobtrusively tracking body fluid shifts in different segments simultaneously, over a broad frequency range, for long periods and with high measurements rate. These needs are often required to evaluate exercise tests in sports or rehabilitation medicine, or to assess gravitational stresses in aerospace medicine. Therefore, the aim of this work is to present a new wearable prototype for monitoring multi-segment and multi-frequency BIS unobtrusively over long periods. Our prototype guarantees low weight, small size and low power consumption. An analog board with current-injecting and voltage-sensing electrodes across three body segments interfaces a digital board that generates square-wave current stimuli and computes impedance at 10 frequencies from 1 to 796 kHz. To evaluate the information derivable from our device, we monitored the BIS of three body segments in a volunteer before, during and after physical exercise and postural shift. We show that it can describe the dynamics of exercise-induced changes and the effect of a sit-to-stand maneuver in active and inactive muscular districts separately and simultaneously. PMID:27187389

  9. Specific bioelectrical impedance vector analysis (BIVA) is more accurate than classic BIVA to detect changes in body composition and in nutritional status in institutionalised elderly with dementia.

    Science.gov (United States)

    Camina Martín, M Alicia; de Mateo Silleras, Beatriz; Barrera Ortega, Sara; Domínguez Rodríguez, Luis; Redondo del Río, M Paz

    2014-09-01

    A new analytical variation of bioelectrical impedance vector analysis (BIVA), called specific BIVA, has shown to be more accurate in detecting changes in fat mass than classic BIVA. To compare classic and specific BIVA in order to identify which is more strongly associated with psycho-functional and nutritional indicators in a group of institutionalised elderly patients with dementia. Cross-sectional study. Fifty-four patients (34 women, 20 men) with dementia in moderately severe to very severe stages and aged 60-95years underwent geriatric nutritional assessment, including body mass index calculations, the Mini Nutritional Assessment, the Geriatric Nutritional Risk Index, and whole body composition analysis. With specific BIVA (unlike with classic BIVA), significant differences were found between women with moderately severe and very severe dementia. In the BIVA conducted for body mass index, the confidence ellipses produced with the classic BIVA approach were highly overlapping; but with specific BIVA, significant differences were observed between the women in different nutritional categories (malnutrition, risk of malnutrition, normal weight and obesity). On the other hand, both approaches distinguished malnourished women from those who were at risk of malnutrition, according to the Mini Nutritional Assessment; and men with a moderate-high risk of malnutrition from men with no risk, on the basis of the Geriatric Nutritional Risk Index. Overall, the findings of the present study suggest that specific BIVA is more effective than classic BIVA in identifying bioelectrical changes associated with psycho-functional and nutritional indicators in institutionalised elderly with dementia. Copyright © 2014 Elsevier Inc. All rights reserved.

  10. Utility of multifrequency bioelectrical impedance compared with dual-energy x-ray absorptiometry for assessment of total and regional body composition varies between men and women.

    Science.gov (United States)

    Anderson, Lindsey J; Erceg, David N; Schroeder, E Todd

    2012-07-01

    Multifrequency bioelectrical impedance analysis of body composition may be an appropriate alternative to dual-energy x-ray absorptiometry. We hypothesized that there would be no significant differences between dual-energy x-ray absorptiometry and either the Biospace (Los Angeles, CA, USA) InBody 520 or 720 multifrequency bioelectrical impedance analysis devices for total lean body mass (LBM), appendicular lean mass (ALM), trunk lean mass (TM), and total fat mass (FM) in 25 men and 25 women (including lean, healthy, and obese individuals according to body mass index), age 18 to 49 years, weight of 73.6 ± 15.4 kg. Both devices overestimated LBM in women (~2.5 kg, P < .001) and underestimated ALM in men (~3.0 kg, P < .05) and women (~1.0 kg, P < .05). The 720 overestimated FM in men (1.6 kg, P < .05) and underestimated TM in women (0.6 kg, P ≤ .05). Regression analyses in men revealed R² (0.87-0.91), standard error of the estimate (SEE; 2.3-2.8 kg), and limits of agreement (LOAs; 4.5-5.7 kg) for LBM; R(2) (0.62-0.87), SEE (1.5-2.6 kg), and LOA (3.2-6.0 kg) for ALM; R² (0.52-0.71), SEE (2.4-3.0 kg), and LOA (4.6-6.1 kg) for TM; and R(2) (0.87-0.93), SEE (1.9-2.6 kg), and LOA (5.9-6.2 kg) for FM. Regression analyses in women revealed R² (0.87-0.88), SEE (1.8-1.9 kg), and LOA (4.1-4.2 kg) for LBM; R² (0.78-0.79), SEE (1.4-1.5 kg), and LOA (2.7-2.9 kg) for ALM; R² (0.76-0.77), SEE (1.0 kg), and LOA (2.2-2.3 kg) for TM; and R² (0.95), SEE (2.2 kg), and LOA (4.3-4.4 kg) for FM. The InBody 520 and 720 are valid estimators of LBM and FM in men and of LBM, ALM, and FM in women; the 720 and 520 are valid estimators of TM in men and women, respectively. Copyright © 2012 Elsevier Inc. All rights reserved.

  11. Concordance between muscle mass assessed by bioelectrical impedance analysis and by dual energy X-ray absorptiometry: a cross-sectional study.

    Science.gov (United States)

    Buckinx, Fanny; Reginster, Jean-Yves; Dardenne, Nadia; Croisiser, Jean-Louis; Kaux, Jean-François; Beaudart, Charlotte; Slomian, Justine; Bruyère, Olivier

    2015-03-18

    Besides magnetic resonance imaging, dual energy X-ray absorptiometry (DXA) seems the most reliable tool to evaluate body composition and is often considered as the gold standard in clinical practice. Bioelectrical impedance analysis (BIA) could provide a simpler, portative, and less expensive alternative. Because the body composition assessment by BIA is device-dependent, the aim of this study was to appraise the concordance between the specific bioelectrical impedance device InBody S10 and DXA for the body composition evaluation. Body composition, included appendicular lean mass divided by height squared (ALM/ht(2)) was measured by DXA (Hologic QDR Discovery device) and by BIA (InBody S10 Biospace device). Agreement between tools was assessed by means of the Bland Altman method and reliability was determined using the IntraClass Coefficient (ICC). ICC was also computed to assess the reliability of the test-retest performed by the same operator or by two different ones. A total of 219 subjects were enrolled in this study (mean age: 43.7 ± 19.1 years old, 51.6% of women). For the ALM/ht(2), reliability of the test-retest of the BIA was high with an ICC of 0.89 (95%CI: 0.86-0.92) when performed by the same operator and an ICC of 0.77 (95%CI: 0.72-0.82) when performed by two different operators. Agreement between ALM/ht(2) assessed by DXA and BIA was low (ICC = 0.37 (95%CI: 0.25-0.48)). Mean ALM/ht(2) was 9.19 ± 1.39 kg/m(2) with BIA and 7.34 ± 1.34 kg/m(2) with DXA, (p < 0001). A formula developed using a multiple regression analysis, and taking into account muscle mass assessed by BIA, as well as sex and body mass index, explains 89% of the ALM/ht(2) assessed by DXA. Although our results show that the measure of ALM/ht(2) by BIA is reliable, the agreement between DXA and BIA is low. Indeed, BIA seems to overestimate ALM/ht(2) compared to DXA and, consequently, it is important to use an adapted formula to obtain measurement of the

  12. Calibration of bioelectrical impedance analysis for body composition assessment in Ethiopian infants using air-displacement plethysmography

    DEFF Research Database (Denmark)

    Christensen, Rasmus Wibæk; Kæstel, Pernille; Skov, R.

    2015-01-01

    , age and an impedance index (L(2)/Z50) were predictors. Prediction equations were developed using stepwise multiple linear regression and the accuracy was evaluated with a 10-fold cross-validation approach. RESULTS: A linear regression model based on body weight, age and sex predicted FFM, estimated...

  13. Body composition in male elite athletes, comparison of bioelectrical impedance spectroscopy with dual energy X-ray absorptiometry

    Directory of Open Access Journals (Sweden)

    Klingberg Sofia

    2008-01-01

    Full Text Available Abstract Background The aim of this study was to compare body composition results from bioelectrical spectroscopy (BIS with results from dual energy X-ray absorptiometry (DXA in a population of male elite athletes. Body composition was assessed using DXA (Lunar Prodigy, GE Lunar Corp., Madison, USA and BIS (Hydra 4200, Xitron Technologies Inc, San Diego, California, USA at the same occasion. Agreement between methods was assessed using paired t-tests and agreement-plots. Results Thirty-three male elite athletes (soccer and ice hockey were included in the study. The results showed that BIS underestimates the proportion of fat mass by 4.6% points in the ice hockey players. In soccer players the BIS resulted in a lower mean fat mass by 1.1% points. Agreement between the methods at the individual level was highly variable. Conclusion Body composition results assessed by BIS in elite athletes should be interpreted with caution, especially in individual subjects. BIS may present values of fat mass that is either higher or lower than fat mass assessed by DXA, independent of true fat content of the individual.

  14. Bipolar bioelectrical impedance: lack of accuracy in estimating relative body fat in men. DOI: 10.5007/1980-0037.2011v13n2p100

    Directory of Open Access Journals (Sweden)

    Cassiano Ricardo Rech

    2011-02-01

    Full Text Available Bioelectrical impedance (BI is commonly used to estimate body composition in different populations. The aim of this study was to determine the accuracy of bipolar BI (Omron BF 300 in estimating relative body fat (%F by comparing it with dual-energy X-ray absorptiometry (DEXA. %F was measured in 66 men (18 to 33 years with a mean body weight of 73.7 ± 8.4 kg, height of 175.1 ± 6.5 cm, body mass index of 23.9 ± 2.2 kg/m2, %FBI 15.1 ± 4.4%, and %FDEXA 17.7 ± 5.1%. A paired t-test, correlation test, standard error of the estimate (SEE, and residue analysis were used to evaluate the accuracy of the method. BI significantly (p 3.5%F in 42% of the sample. In subjects with higher fat accumulation (%F >20%, the Omron BF BI model produced greater bias in the %F measurement. Therefore, in the case of adult men, the Omron BF 300 BI model does not agree with the DEXA measurement for the estimation of %F in adult men. In addition, the higher the level of fat accumulation, the higher the error in estimated %F.

  15. Prognostic value of decreased peripheral congestion detected by Bioelectrical Impedance Vector Analysis (BIVA) in patients hospitalized for acute heart failure: BIVA prognostic value in acute heart failure.

    Science.gov (United States)

    Santarelli, Simona; Russo, Veronica; Lalle, Irene; De Berardinis, Benedetta; Vetrone, Francesco; Magrini, Laura; Di Stasio, Enrico; Piccoli, Antonio; Codognotto, Marta; Mion, Monica M; Castello, Luigi M; Avanzi, Gian Carlo; Di Somma, Salvatore

    2017-06-01

    The objective of this study was to investigate the prognostic role of quantitative reduction of congestion during hospitalization assessed by Bioelectrical Impedance Vector Analysis (BIVA) serial evaluations in patients admitted for acute heart failure (AHF). AHF is a frequent reason for patients to be admitted. Exacerbation of chronic heart failure is linked with a progressive worsening of the disease with increased incidence of death. Fluid overload is the main mechanism underlying acute decompensation in these patients. BIVA is a validated technique able to quantify fluid overload. a prospective, multicentre, observational study in AHF and no AHF patients in three Emergency Departments centres in Italy. Clinical data and BIVA evaluations were performed at admission (t0) and discharge (tdis). A follow-up phone call was carried out at 90 days. Three hundred and thirty-six patients were enrolled (221 AHF and 115 no AHF patients). We found that clinical signs showed the most powerful prognostic relevance. In particular the presence of rales and lower limb oedema at tdis were linked with events relapse at 90 days. At t0, congestion detected by BIVA was observed only in the AHF group, and significantly decreased at tdis. An increase of resistance variation (dR/H) >11 Ω/m during hospitalization was associated with survival. BIVA showed significant results in predicting total events, both at t0 (area under the curve (AUC) 0.56, p11 Ω/m during hospitalization seems to be associated with increased 90 day survival in patients admitted for AHF.

  16. Residential neighborhood, geographic work environment, and work economic sector: associations with body fat measured by bioelectrical impedance in the RECORD Study.

    Science.gov (United States)

    Lewin, Antoine; Pannier, Bruno; Méline, Julie; Karusisi, Noëlla; Thomas, Frédérique; Chaix, Basile

    2014-03-01

    Studies of associations between geographic environment and obesity have mostly examined body mass index and focused on residential neighborhoods. We investigated associations between residential neighborhoods, geographic work environments, and work economic sectors and the fat mass index (FMI) and percentage of fat mass (%FM). Data on 4331 participants from the French RECORD Study geolocated at their residence and workplace were analyzed. Body composition was assessed by bioelectrical impedance analyzers. Multilevel linear regression was used to investigate the determinants of FMI and %FM. After adjustment, among men, the FMI and %FM increased independently with decreasing density of population and educational level in the residential neighborhood. Among women, the residential educational level was related to the FMI and %FM. Among men, a higher FMI and %FM were observed among participants working in the construction and transportation/communication sectors than in the education sector. For women, the FMI was higher among participants working in the public administration and health/social work sectors than in the transport/communication sector. A long home-work distance was associated with a higher FMI among women. There was evidence that body mass index cannot fully capture work economic sector effects on fat mass. Public health interventions to reduce social/territorial disparities in obesity should also consider the different contexts to which the participants belong, such as residential environments and work economic sectors. Copyright © 2014 Elsevier Inc. All rights reserved.

  17. Comparison of dual-energy X-ray absorptiometry, air displacement plethysmography and bioelectrical impedance analysis for the assessment of body composition in morbidly obese women.

    Science.gov (United States)

    Bedogni, G; Agosti, F; De Col, A; Marazzi, N; Tagliaferri, A; Sartorio, A

    2013-11-01

    We evaluated the agreement of air displacement plethysmography (ADP) and bioelectrical impedance analysis (BIA) with dual-energy X-ray absorptiometry (DXA) for the assessment of percent fat mass (%FM) in morbidly obese women. Fifty-seven women aged 19-55 years and with a body mass index (BMI) ranging from 37.3 to 55.2 kg/m(2) were studied. Values of %FM were obtained directly from ADP and DXA, whereas for BIA we estimated fat-free mass (FFM) from an equation for morbidly obese subjects and calculated %FM as (weight-FFM)/weight. The mean (s.d.) difference between ADP and DXA for the assessment of %FM was -2.4% (3.3%) with limits of agreement (LOA) from -8.8% to 4.1%. The mean (s.d.) difference between BIA and DXA for the assessment of %FM was 1.7% (3.3%) with LOA from -4.9% to 8.2%. ADP-DXA and BIA-DXA are not interchangeable methods for the assessment of body composition in morbidly obese women.

  18. Practical Considerations for Body Composition Assessment of Adults with Class II/III Obesity Using Bioelectrical Impedance Analysis or Dual-Energy X-Ray Absorptiometry.

    Science.gov (United States)

    Johnson Stoklossa, Carlene A; Forhan, Mary; Padwal, Raj S; Gonzalez, Maria Cristina; Prado, Carla M

    2016-12-01

    The purpose of this review is to explore the practical considerations for body composition assessment of adults with class II/III obesity. Studies assessing adults (18-64 years) with a body mass index (BMI) ≥35 kg/m 2 with bioelectrical impedance analysis (BIA) and/or dual-energy X-ray absorptiometry (DXA) were included. Twelve studies met inclusion criteria. Five considerations were identified: variances in equipment and technology, equipment weight capacity, subject positioning, tissue penetration, and total body hydration. In subjects with BMI ≥35 kg/m 2 , BIA overestimated fat-free mass with scaling errors as BMI increased. DXA provided accurate and reliable body composition measures, but equipment-related barriers prevented assessment of some taller, wider, and heavier subjects. BIA is an unreliable method to assess body composition in class II/III obesity. Advancements in DXA technology (e.g., iDXA), methodology (e.g., subject positioning, longer scan times), and more inclusive testing criteria (e.g., use equipment limits not just BMI) may improve access and understanding of body composition in this cohort.

  19. The Impact of Feet Callosities, Arm Posture, and Usage of Electrolyte Wipes on Body Composition by Bioelectrical Impedance Analysis in Morbidly Obese Adults

    Directory of Open Access Journals (Sweden)

    Jessica Roekenes

    2015-11-01

    Full Text Available Objective: This study evaluated the impact of feet callosities, arm posture, and use of electrolyte wipes on body composition measurements by bioelectrical impedance analysis (BIA in morbidly obese adults. Methods: 36 morbidly obese patients (13 males, aged 28-70 years, BMI 41.6 ± 4.3 kg/m2 with moderate/severe feet callosities participated in this study. Body composition (percent body fat (%BF was measured while fasting using multi-frequency BIA (InBody 720®, before and after removal of callosities, with and without InBody® electrolyte wipes and custom-built auxiliary pads (to assess arm posture impact. Results from BIA were compared to air displacement plethysmography (ADP, BodPod®. Results: Median %BF was significantly higher with auxiliary pads than without (50.1 (interquartile range 8.2 vs. 49.3 (interquartile range 9.1; p Conclusion: Arm posture has a significant impact on %BF assessed by BIA, contrary to the presence of feet callosities and use of electrolyte wipes. Arm posture standardization during BIA for body composition assessment is, therefore, recommended.

  20. Comparison of two bioelectrical impedance devices and dual-energy X-ray absorptiometry to evaluate body composition in heart failure.

    Science.gov (United States)

    Alves, F D; Souza, G C; Biolo, A; Clausell, N

    2014-12-01

    The utilisation of bioelectrical impedance analysis (BIA) in heart failure can be affected by many factors and its applicability remains controversial. The present study aimed to verify the adequacy of single-frequency BIA (SF-BIA) and multifrequency BIA (MF-BIA) compared to dual-energy x-ray absorptiometry (DEXA) for evaluating body composition in outpatients with heart failure. In this cross-sectional study, 55 patients with stable heart failure and left ventricle ejection fraction ≤45% were evaluated for fat mass percentage, fat mass and fat-free mass by DEXA and compared with the results obtained by SF-BIA (single frequency of 50 kHz) and MF-BIA (frequencies of 20 and 100 kHz). MF-BIA and DEXA gave similar mean values for fat mass percentage, fat mass and fat-free mass, whereas values from SF-BIA were significantly different from DEXA. Both SF-BIA and MF-BIA measures of body composition correlated strongly with DEXA (r > 0.8; P  0.05), except MF-BIA for fat-free mass. Compared with DEXA, MF-BIA showed better accuracy than SF-BIA, although both types of equipment showed wide limits of agreement. The BIA technique should be used with caution, and regression equations might be useful for correcting the observed variations, mainly in extreme values of body composition. © 2014 The British Dietetic Association Ltd.

  1. Body composition of adult cystic fibrosis patients and control subjects as determined by densitometry, bioelectrical impedance, total-body electrical conductivity, skinfold measurements, and deuterium oxide dilution

    Energy Technology Data Exchange (ETDEWEB)

    Newby, M.J.; Keim, N.L.; Brown, D.L. (Univ. of California, Davis (USA))

    1990-08-01

    This study contrasts body compositions (by six methods) of eight cystic fibrosis (CF) subjects with those of eight control subjects matched for age, height, and sex. CF subjects weighed 84% as much as control subjects. Densitometry and two bioelectrical impedance-analysis methods suggested that reduced CF weights were due to less lean tissue (10.7, 9.5, and 10.4 kg). Total-body electrical conductivity (TOBEC) and skinfold-thickness measurements indicated that CF subjects were leaner than control subjects and had less fat (5.4 and 3.6 kg) and less lean (5.2 and 7 kg) tissue. D2O dilution showed a pattern similar to TOBEC (8.3 kg less lean, 2.7 kg less fat tissue). Densitometry estimates of fat (mass and percent) were not correlated (r less than 0.74, p greater than 0.05) with any other method for CF subjects but were correlated with all other methods for control subjects. CF subjects contained less fat and lean tissue than did control subjects. Densitometry by underwater weighing is unsuitable for assessing body composition of CF patients.

  2. The Performance of Five Bioelectrical Impedance Analysis Prediction Equations against Dual X-ray Absorptiometry in Estimating Appendicular Skeletal Muscle Mass in an Adult Australian Population.

    Science.gov (United States)

    Yu, Solomon C Y; Powell, Alice; Khow, Kareeann S F; Visvanathan, Renuka

    2016-03-29

    Appendicular skeletal muscle mass (ASM) is a diagnostic criterion for sarcopenia. Bioelectrical impedance analysis (BIA) offers a bedside approach to measure ASM but the performance of BIA prediction equations (PE) varies with ethnicities and body composition. We aim to validate the performance of five PEs in estimating ASM against estimation by dual-energy X-ray absorptiometry (DXA). We recruited 195 healthy adult Australians and ASM was measured using single-frequency BIA. Bland-Altman analysis was used to assess the predictive accuracy of ASM as determined by BIA against DXA. Precision (root mean square error (RMSE)) and bias (mean error (ME)) were calculated according to the method of Sheiner and Beal. Four PEs (except that by Kim) showed ASM values that correlated strongly with ASMDXA (r ranging from 0.96 to 0.97, p < 0.001). The Sergi equation performed the best with the lowest ME of -1.09 kg (CI: -0.84--1.34, p < 0.001) and the RMSE was 2.09 kg (CI: 1.72-2.47). In men, the Kyle equation performed better with the lowest ME (-0.32 kg (CI: -0.66-0.02) and RMSE (1.54 kg (CI: 1.14-1.93)). The Sergi equation is applicable in adult Australians (Caucasian) whereas the Kyle equation can be considered in males. The need remains to validate PEs in other ethnicities and to develop equations suitable for multi-frequency BIA.

  3. Fat-free mass in chronic illness: comparison of bioelectrical impedance and dual-energy x-ray absorptiometry in 480 chronically ill and healthy subjects.

    Science.gov (United States)

    Pichard, C; Kyle, U G; Slosman, D O

    1999-09-01

    Assessment of fat-free mass (FFM) and fat mass in ambulatory and hospitalized patients permits optimal adaptation of nutrition support. Recent methods for the determination of FFM are dual-energy x-ray absorptiometry (DXA) and bioelectrical impedance analysis (BIA). The purpose of this study was to determine if the BIA-determined FFM as estimated by the formula by Kotler et al. and the Geneva formula could be validated when compared to DXA-determined FFM in subjects with various diagnoses. Body composition was measured by BIA and DXA in 480 subjects including healthy young men and women, elite female runners, and patients with various pathologies (including chronic obstructive and restrictive pulmonary disease patients; cystic fibrosis patients; lung, heart, and liver transplantation patients [both pre- and post-], and hemiplegic and AIDS patients). The present results suggest that BIA is relevant in the clinical assessment of body composition, but BIA formulas appropriate to the subject pool must be used for evaluation of FFM and fat mass. The BIA formula by Kotler et al. is appropriate for healthy subjects and patients with AIDS, cystic fibrosis, and pre- or postliver transplantation. The Geneva formula is more appropriate in pulmonary diseases and hemiplegic subjects with normal weight.

  4. The Impact of Feet Callosities, Arm Posture, and Usage of Electrolyte Wipes on Body Composition by Bioelectrical Impedance Analysis in Morbidly Obese Adults.

    Science.gov (United States)

    Roekenes, Jessica; Strømmen, Magnus; Kulseng, Bård; Martins, Catia

    2015-01-01

    This study evaluated the impact of feet callosities, arm posture, and use of electrolyte wipes on body composition measurements by bioelectrical impedance analysis (BIA) in morbidly obese adults. 36 morbidly obese patients (13 males, aged 28-70 years, BMI 41.6 ± 4.3 kg/m2) with moderate/severe feet callosities participated in this study. Body composition (percent body fat (%BF)) was measured while fasting using multi-frequency BIA (InBody 720®), before and after removal of callosities, with and without InBody® electrolyte wipes and custom-built auxiliary pads (to assess arm posture impact). Results from BIA were compared to air displacement plethysmography (ADP, BodPod®). Median %BF was significantly higher with auxiliary pads than without (50.1 (interquartile range 8.2) vs. 49.3 (interquartile range 9.1); p interquartile range 9.1) vs. 50.0 (interquartile range 7.9); NS) or use of wipes (49.6 (interquartile range 8.5) vs. 49.3 (interquartile range 9.1); NS). No differences in %BF were found between BIA and ADP (49.1 (IQR: 8.9) vs. 49.3 (IQR: 9.1); NS). Arm posture has a significant impact on %BF assessed by BIA, contrary to the presence of feet callosities and use of electrolyte wipes. Arm posture standardization during BIA for body composition assessment is, therefore, recommended. © 2015 S. Karger GmbH, Freiburg.

  5. BODY COMPOSITION OF YOUNG PEOPLE AGED 17-18 YEARS, PRACTICING AND NOT PRACTICING SWIMMING, WITH THE USE OF THE BIOELECTRICAL IMPEDANCE METHOD

    Directory of Open Access Journals (Sweden)

    Jendrysek Marek

    2015-11-01

    Full Text Available Purpose: Body composition evaluation of youth aged 17-18 of a different physical activity with the help of bioelectric impedance method. Material and Methods: 18 boys practicing swimming and 19 boys not practicing it took part in the study, making up a control group. Height, weight, BMI, lean body mass, the content of fat and water, Rohr factor were evaluated. Non-parametric Mann-Whitney test has been used to evaluate the differences in the range of the tissue components between the two groups. Results: Statistically significant differences were found on the p<0,05 level in % fat content. Mean body weight in experimental group was 71.5 kg, while in control group it was 69.4 kg. Minimum and maximum weight in group of swimming-practicing persons was: 56.6-92.2 kg. Increased body weight in the group of swimmers can result from greater amount of active tissue in this group compared with persons of low physical activity. Proportionally, it amounted to 64.3 kg and 61.3 kg. In the tested groups, minimal and maximal values of amount of active tissue proportionately amounted to: 54.1-78 and 49.5-72,3 kg. Conclusions: Physical activity modifies body composition. Active lifestyle is one of the methods for prevention of overweight and obesity.

  6. Body composition of young people aged 17-18 years, practicing and not practicing swimming, with the use of the bioelectrical impedance method

    Directory of Open Access Journals (Sweden)

    Marek Jendrysek

    2015-11-01

    Full Text Available Purpose: Body composition evaluation of youth aged 17-18 of a different physical activity with the help of bioelectric impedance method. Material and Methods: 18 boys practicing swimming and 19 boys not practicing it took part in the study, making up a control group. Height, weight, BMI, lean body mass, the content of fat and water, Rohr factor were evaluated. Non-parametric Mann-Whitney test has been used to evaluate the differences in the range of the tissue components between the two groups. Results: Statistically significant differences were found on the p<0,05 level in % fat content. Mean body weight in experimental group was 71.5 kg, while in control group it was 69.4 kg. Minimum and maximum weight in group of swimming-practicing persons was: 56.6-92.2 kg. Increased body weight in the group of swimmers can result from greater amount of active tissue in this group compared with persons of low physical activity. Proportionally, it amounted to 64.3 kg and 61.3 kg. In the tested groups, minimal and maximal values of amount of active tissue proportionately amounted to: 54.1-78 and 49.5-72,3 kg. Conclusions: Physical activity modifies body composition. Active lifestyle is one of the methods for prevention of overweight and obesity.

  7. Body composition by bioelectrical-impedance analysis compared with deuterium dilution and skinfold anthropometry in patients with chronic obstructive pulmonary disease

    Energy Technology Data Exchange (ETDEWEB)

    Schols, A.M.; Wouters, E.F.; Soeters, P.B.; Westerterp, K.R. (Univ. of Limburg, Maastricht (Netherlands))

    1991-02-01

    Body composition is an important measure of nutritional status in patients with chronic obstructive pulmonary disease (COPD). We generated a regression model for bioelectrical impedance (BI) by using deuterium dilution (2H2O) as a reference method in 32 COPD patients, aged 63 +/- 9 y (mean +/- SD), in stable pulmonary and cardiac condition. Height squared divided by resistance (Ht2/Res) correlated well with total body water (TBW) as measured by 2H2O (r = 0.93, P less than 0.001, SEE = 1.9 L). The best-fitting regression equation to predict TBW comprised Ht2/Res and body weight (r2 = 0.89, SEE = 1.8 L, P less than 0.001). BI-predicted TBW was used to estimate BI-fat-free mass (FFM) that was compared with skinfold-thickness-based FFM predictions (Anthr-FFM). Relative to BI-FFM a significant overestimation of 4.4 +/- 0.8 kg was found by Anthr-FFM. Our results suggest that BI is a useful measure of body composition in patients with severe COPD.

  8. Developing and Validating an Age-Independent Equation Using Multi-Frequency Bioelectrical Impedance Analysis for Estimation of Appendicular Skeletal Muscle Mass and Establishing a Cutoff for Sarcopenia

    Directory of Open Access Journals (Sweden)

    Yosuke Yamada

    2017-07-01

    Full Text Available Background: Appendicular skeletal muscle (or lean mass (ALM estimated using dual-energy X-ray absorptiometry (DXA is considered to be a preferred method for sarcopenia studies. However, DXA is expensive, has limited portability, and requires radiation exposure. Bioelectrical impedance analysis (BIA is inexpensive, easy to use, and portable; thus BIA might be useful in sarcopenia investigations. However, a large variety of models have been commercially supplied by different companies, and for most consumer products, the equations estimating ALM are not disclosed. It is therefore difficult to use these equations for research purposes. In particular, the BIA equation is often age-dependent, which leads to fundamental difficulty in examining age-related ALM loss. The aims of the current study were as follows: (1 to develop and validate an equation to estimate ALM using multi-frequency BIA (MF-BIA based on theoretical models, and (2 to establish sarcopenia cutoff values using the equation for the Japanese population. Methods: We measured height (Ht, weight, and ALM obtained using DXA and a standing-posture 8-electrode MF-BIA (5, 50, 250 kHz in 756 Japanese individuals aged 18 to 86-years-old (222 men and 301 women as developing equation group and 97 men and 136 women as a cross validation group. The traditional impedance index (Ht2/Z50 and impedance ratio of high and low frequency (Z250/Z5 of hand to foot values were calculated. Multiple regression analyses were conducted with ALM as dependent variable in men and women separately. Results: We created the following equations: ALM = (0.6947 × (Ht2/Z50 + (−55.24 × (Z250/Z5 + (−10,940 × (1/Z50 + 51.33 for men, and ALM = (0.6144 × (Ht2/Z50 + (−36.61 × (Z250/Z5 + (−9332 × (1/Z50 + 37.91 for women. Additionally, we conducted measurements in 1624 men and 1368 women aged 18 to 40 years to establish sarcopenia cutoff values in the Japanese population. The mean values minus 2 standard deviations

  9. Developing and Validating an Age-Independent Equation Using Multi-Frequency Bioelectrical Impedance Analysis for Estimation of Appendicular Skeletal Muscle Mass and Establishing a Cutoff for Sarcopenia.

    Science.gov (United States)

    Yamada, Yosuke; Nishizawa, Miyuki; Uchiyama, Tomoka; Kasahara, Yasuhiro; Shindo, Mikio; Miyachi, Motohiko; Tanaka, Shigeho

    2017-07-19

    Background: Appendicular skeletal muscle (or lean) mass (ALM) estimated using dual-energy X-ray absorptiometry (DXA) is considered to be a preferred method for sarcopenia studies. However, DXA is expensive, has limited portability, and requires radiation exposure. Bioelectrical impedance analysis (BIA) is inexpensive, easy to use, and portable; thus BIA might be useful in sarcopenia investigations. However, a large variety of models have been commercially supplied by different companies, and for most consumer products, the equations estimating ALM are not disclosed. It is therefore difficult to use these equations for research purposes. In particular, the BIA equation is often age-dependent, which leads to fundamental difficulty in examining age-related ALM loss. The aims of the current study were as follows: (1) to develop and validate an equation to estimate ALM using multi-frequency BIA (MF-BIA) based on theoretical models, and (2) to establish sarcopenia cutoff values using the equation for the Japanese population. Methods: We measured height (Ht), weight, and ALM obtained using DXA and a standing-posture 8-electrode MF-BIA (5, 50, 250 kHz) in 756 Japanese individuals aged 18 to 86-years-old (222 men and 301 women as developing equation group and 97 men and 136 women as a cross validation group). The traditional impedance index (Ht²/Z 50 ) and impedance ratio of high and low frequency (Z 250 /Z₅) of hand to foot values were calculated. Multiple regression analyses were conducted with ALM as dependent variable in men and women separately. Results: We created the following equations: ALM = (0.6947 × (Ht²/Z 50 )) + (-55.24 × (Z 250 /Z₅)) + (-10,940 × (1/Z 50 )) + 51.33 for men, and ALM = (0.6144 × (Ht²/Z 50 )) + (-36.61 × (Z 250 /Z₅)) + (-9332 × (1/Z 50 )) + 37.91 for women. Additionally, we conducted measurements in 1624 men and 1368 women aged 18 to 40 years to establish sarcopenia cutoff values in the Japanese population. The mean values minus 2

  10. Bioelectrical impedance values among indigenous children and adolescents in Rio Grande do Sul, Brazil Valores de impedancia bioeléctrica en niños y adolescentes indígenas en Rio Grande do Sul, Brasil

    Directory of Open Access Journals (Sweden)

    Laura Augusta Barufaldi

    2011-07-01

    Full Text Available OBJECTIVE: To describe the nutritional status of indigenous children and adolescents in Rio Grande do Sul, Brazil, through bioelectrical values, and to compare the nutritional classifications of the anthropometric method to those of the body composition method. METHODS: A cross-sectional survey was conducted of 3 204 subjects at 35 schools in the 12 Kaingang indigenous lands of Rio Grande do Sul, Brazil. Following World Health Organization recommendations, the weight and height (H of each subject was measured twice and the body mass index/age (BMI/A was classified. Body composition was assessed by Bioelectrical Impedance Vector Analysis (BIVA. Resistance (R and reactance (Xc were estimated using a bioelectrical impedance analyzer. Divergences between these two methods were performed on RXc graph. RESULTS: Of the sample, 56.8% were adolescents and 50.6% were males. The mean values of phase angle were higher in adolescents, in males, and in individuals overweight by BMI/A. Mean values of R, Xc, R/H, and Xc/H were higher among children and among those with BMI/A OBJETIVO: Describir el estado nutricional de niños y adolescentes indígenas en Rio Grande do Sul, Brasil, mediante los valores de impedancia bioeléctrica y comparar las clasificaciones nutricionales del método antropométrico con las del método de composición corporal. MÉTODOS: Se llevó a cabo un estudio transversal en 3 204 participantes de 35 escuelas de los 12 territorios indígenas habitados por el pueblo kaingang (o guayaná del estado de Rio Grande do Sul (Brasil. Según las recomendaciones de la Organización Mundial de la Salud, se midió el peso y la talla (T de cada participante en dos oportunidades y se clasificó el índice de masa corporal (IMC según la edad. La composición corporal se evaluó mediante análisis vectorial de impedancia bioeléctrica. La resistencia (R y la reactancia (Xc se calcularon con un analizador de impedancia bioeléctrica. Las divergencias

  11. Impedance Studies for the Phase 2 LHC Collimators

    CERN Document Server

    Métral, E; Grudiev, A; Kroyer, T; Zotter, B; Roncarolo, F; Salvant, B

    2010-01-01

    The LHC phase 2 collimation project aims at gaining a factor ten in cleaning efficiency, robustness and impedance reduction. From the impedance point of view, several ideas emerged during the last year, such as using dielectric collimators, slots or rods in copper plates, or Litz wires. The purpose of this paper is to discuss the possible choices, showing analytical estimates, electromagnetic simulations performed using Maxwell, HFSS and GdFidL, and preliminary bench measurements. The corresponding complex tune shifts are computed for the different cases and compared on the stability diagram defined by the settings of the Landau octupoles available in the LHC at 7 TeV.

  12. [Comparison BMC assessed by dual-energy X-ray absorptiometry and multi-frequency bioelectrical impedance in Chinese overweight and obesity adults].

    Science.gov (United States)

    Wang, Zhenghe; Fu, Lianguo; Yang, Yide; Wang, Shuo; Ma, Jun

    2016-05-01

    To compare consistency of Body Mineral Content (BMC, kg) assessed by Multi-frequency Bioelectrical Impedance Analysis ( MF-BIA) and Dual Energy X-ray Absorptiometry (DXA) measurement, providing evidence for MF-BIA accurate application in Chinese overweight/obese adults. A total of 1323 overweight/obesity adults aged 22-55 years were recruited voluntarily. All the subjects received the measurement of BMC both using MF-BIA and DXA. To evaluate the agreement of BMC measured by MF-BIA and DXA using interclass correlation coefficients (ICC), then establish correction prediction models. The mean difference of BMC between two methods was significant different with 0, overweight male subgroup was 0.28 kg, and 0.38 kg for obesity male, 0.24 kg for overweight female and 0.36 kg for obesity female, respectively (P obesity male, 0.741 for overweight female and 0.788 for obesity female, respectively. Correction prediction model: overweight male population: BMC (DXA method) = -0.297 + 1.005 x BMC (MF-BIA method). Obese male population: BMC (DXA method) =0.302 + 0.799 x BMC (MF-BIA method). Overweight female groups: BMC (DXA method) = 0.780 + 0.598 x BMC (MF-BIA method). Obese female group: BMC (DXA method) = 0.755 + 0.597 x BMC (MF-BIA method). Upon examination, correction prediction models were better. Co The correlation and agreement of BMC measured by BIA and DXA are weak in Chinese overweight/obese adults. Therefore, consideration should be given to BMC measured by BIA method in Chinese overweight/obese adults. It should be corrected or adjusted to reduce errors compared with DXA method.

  13. Percentage of body fat assessment using bioelectrical impedance analysis and dual-energy X-ray absorptiometry in a weight loss program for obese or overweight Chinese adults.

    Directory of Open Access Journals (Sweden)

    Yi-Chun Li

    Full Text Available The current study aimed to compare the estimates of body fat percentage (%BF by performing bioelectrical impedance analysis (BIA and dual energy X-ray absorptiometry (DXA in a sample of obese or overweight Chinese adults who participated in a weight-loss randomized control trial stratified by gender to determine whether or not BIA is a valid measurement tool. Among 189 adults [73 males, 116 females; age = 41 to 74 years; mean body mass index (BMI = 27.3 kg/m(2], assessments of %BF at the baseline and six months from the baseline were conducted by performing BIA and DXA. Bland-Altman analyses and multiple regression analyses were used to assess the relationships between %BFBIA and %BFDXA. Compared with DXA, BIA underestimated %BF [in males: 4.6, -2.4 to 11.7 (mean biases, 95% limit of agreement at the baseline, 1.4, -7.4 to 10.2 at the endpoint, and 3.2, -4.8 to 11.3 in changes; in females: 5.1, -2.4 to 12.7; 2.2, -6.1 to 10.4; and 3.0, -4.8 to 10.7, respectively]. For males and females, %BFDXA proved to be a significant predictor of the difference between DXA and BIA at the baseline, the endpoint, and in changes when BMI and age were considered (in males: p<0.01 and R (2 = 23.1%, 24.1%, 20.7%, respectively; for females: p<0.001 and R (2 = 40.4%, 48.8%, 25.4%, respectively. The current study suggests that BIA provides a relatively accurate prediction of %BF in individuals with normal weight, overweight, or obesity after the end of weight-loss program, but less accurate prediction of %BF in obese individuals at baseline or weight change during the weight-loss intervention program.

  14. Obesity in young-adult Nigerians: variations in prevalence determined by anthropometry and bioelectrical impedance analysis, and the development of % body fat prediction equations

    Directory of Open Access Journals (Sweden)

    Ejike Chukwunonso ECC

    2012-07-01

    Full Text Available Abstract Background Overweight/obesity is a growing global public health concern. The variations in the prevalence of overweight/obesity, defined by Body Mass Index (BMI, Waist Circumference (WC, Waist-to-Height Ratio (WHtR, Waist-to-Hip Ratio (WHpR and Bioelectrical Impedance Analysis (BIA, were studied and a prediction equation for % body fat (%BF developed. Methods A total of 1584 subjects (56.4% males were recruited for the study. Data on age, gender, height, weight, hip circumference and WC were collected from the subjects using standard protocols. BMI, WHtR and WHpR were derived using standard equations. %BF was measured using a BIA device (Omron BF-400. Appropriate statistical tools were used for the data analysis. Results The prevalence of overweight/obesity in the population was 28.4% (36.3% for males; 22.6% for females (BIA; 20.7% (17.5% for males; 24.8% for females (BMI; 7.5% (1.3% for males; 16.1% for females (WC; 2.9% (4.3% for males; 1.2% for females (WHpR; and 15.4% (14.8% for males; 16.2% females (WHtR. Taking BIA as the reference point, WC misclassified overweight/obesity the most for males (35%, while for the females, WHpR misclassified both disorders the most (21.4%. Correlation studies showed that only BMI correlated significantly, albeit weakly, with %BF among the males, whereas all the anthropometric measures, but WHpR correlated significantly with % body fat in females. Two prediction equations for %BF were generated, and %BF predicted with the two equations correlated significantly (P  Conclusion The prevalence of overweight/obesity in this population vary widely depending on the definition used. The developed prediction equations could be useful in resource-poor settings, but require validation.

  15. Utility of Volume Assessment Using Bioelectrical Impedance Analysis in Critically Ill Patients Receiving Continuous Renal Replacement Therapy: A Prospective Observational Study

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    Ki Hyun Park

    2017-08-01

    Full Text Available Background Fluid overload prior to continuous renal replacement therapy (CRRT is an important prognostic factor. Thus, precise evaluation of fluid status is necessary to treat such patients. In this study, we investigated whether fluid assessment using bioelectrical impedance analysis (BIA can predict outcomes in critically ill patients requiring CRRT. Methods A prospective observational study was performed in patients who were admitted to the intensive care unit and who required CRRT. BIA was conducted before CRRT; then, the ratio of extracellular water to total body water (ECW/TBW was derived to estimate volume status. Results A total of 31 patients treated with CRRT were included. There were 18 men (58.1%, and the median age was 67 years (interquartile range, 51 to 78 years. Fourteen patients (45.2% died within 28 days after CRRT initiation. Patients were divided into 16 with ECW/TBW ≥0.41 and 15 with ECW/TBW <0.41. Survival rate within 28 days was different between the two groups (P = 0.044. Cox regression analysis revealed a relationship between ECW/TBW ≥0.41 and 28-day mortality, but it was not statistically significant (hazard ratio, 3.0; 95% confidence interval, 0.9 to 9.8; P = 0.061. Lastly, the area under the curve of ECW/TBW for 28-day mortality was analyzed. The area under the curve of ECW/TBW was 0.73 (95% confidence interval, 0.54 to 0.92, and this was significant (P = 0.037. Conclusions Fluid status can be assessed using BIA in critically ill patients requiring CRRT, and BIA can predict mortality. Further large trials are needed to confirm the usefulness of BIA in critically ill patients.

  16. Prediction of fat-free mass by bioelectrical impedance analysis in older adults from developing countries: a cross-validation study using the deuterium dilution method

    International Nuclear Information System (INIS)

    Mateo, H. Aleman; Romero, J. Esparza; Valencia, M.E.

    2010-01-01

    Objective: Several limitations of published bioelectrical impedance analysis (BIA) equations have been reported. The aims were to develop in a multiethnic, elderly population a new prediction equation and cross- validate it along with some published BIA equations for estimating fat-free mass using deuterium oxide dilution as the reference method. Design and setting: Cross-sectional study of elderly from five developing countries. Methods: Total body water (TBW) measured by deuterium dilution was used to determine fat-free mass (FFM) in 383 subjects. Anthropometric and BIA variables were also measured. Only 377 subjects were included for the analysis, randomly divided into development and cross-validation groups after stratified by gender. Stepwise model selection was used to generate the model and Bland Altman analysis was used to test agreement. Results: FFM = 2.95 - 3.89 (Gender) + 0.514 (Ht2/Z) + 0.090 (Waist) + 0.156 (Body weight). The model fit parameters were an R2, total F-Ratio, and the SEE of 0.88, 314.3, and 3.3, respectively. None of the published BIA equations met the criteria for agreement. The new BIA equation underestimated FFM by just 0.3 kg in the cross-validation sample. The mean of the difference between FFM by TBW and the new BIA equation were not significantly different; 95% of the differences were between the limits of agreement of -6.3 to 6.9 kg of FFM. There was no significant association between the mean of the differences and their averages (r= 0.008 and p= 0.2). Conclusions:This new BIA equation offers a valid option compared with some of the current published BIA equations to estimate FFM in elderly subjects from five developing countries. (Authors)

  17. Percentage of body fat assessment using bioelectrical impedance analysis and dual-energy X-ray absorptiometry in a weight loss program for obese or overweight Chinese adults.

    Science.gov (United States)

    Li, Yi-Chun; Li, Chia-Ing; Lin, Wen-Yuan; Liu, Chiu-Shong; Hsu, Hua-Shui; Lee, Cheng-Chun; Chen, Fei-Na; Li, Tsai-Chung; Lin, Cheng-Chieh

    2013-01-01

    The current study aimed to compare the estimates of body fat percentage (%BF) by performing bioelectrical impedance analysis (BIA) and dual energy X-ray absorptiometry (DXA) in a sample of obese or overweight Chinese adults who participated in a weight-loss randomized control trial stratified by gender to determine whether or not BIA is a valid measurement tool. Among 189 adults [73 males, 116 females; age = 41 to 74 years; mean body mass index (BMI) = 27.3 kg/m(2)], assessments of %BF at the baseline and six months from the baseline were conducted by performing BIA and DXA. Bland-Altman analyses and multiple regression analyses were used to assess the relationships between %BFBIA and %BFDXA. Compared with DXA, BIA underestimated %BF [in males: 4.6, -2.4 to 11.7 (mean biases, 95% limit of agreement) at the baseline, 1.4, -7.4 to 10.2 at the endpoint, and 3.2, -4.8 to 11.3 in changes; in females: 5.1, -2.4 to 12.7; 2.2, -6.1 to 10.4; and 3.0, -4.8 to 10.7, respectively]. For males and females, %BFDXA proved to be a significant predictor of the difference between DXA and BIA at the baseline, the endpoint, and in changes when BMI and age were considered (in males: pobesity after the end of weight-loss program, but less accurate prediction of %BF in obese individuals at baseline or weight change during the weight-loss intervention program.

  18. Segmental fat-free and fat mass measurements by bioelectrical impedance analysis in 2,224 healthy Spanish women aged 18-85 years.

    Science.gov (United States)

    Pedrera-Zamorano, Juan D; Roncero-Martin, Raul; Lavado-Garcia, Jesus M; Calderon-Garcia, Julian F; Rey-Sanchez, Purificacion; Vera, Vicente; Martinez, Mariana; Moran, Jose M

    2015-01-01

    This study provides updated data on body composition in adult Spanish women. We considered data, including height and weight, from a survey conducted on a total of 4,013 adult women between 2009 and 2010. A subgroup of 2,224 women completed a bioelectrical body impedance analysis of body composition using a Tanita Body Composition Analyzer (Model no. BF-418). Total fat mass (FM) gradually increased between 18 and 74 years of age and decreased thereafter. FM increased in both legs between 65 and 74 years of age (5.69 ± 1.4 Kg and 5.66 ± 1.4 Kg for right and left legs, respectively) and decreased thereafter. FM in the right arm increased until 44 years of age (1.22 ± 2.6 Kg), decreased to 1.19 ± 0.5 Kg between 45 and 54 years of age, and increased to 1.54 ± 0.63 from 65 to 74 years of age. FM in the left arm increased constantly until it reached a peak of 1.63 ± 0.6 Kg between 65 and 74 years of age and decreased thereafter. FM increased in the trunk throughout life (peaks at 13.27±3.8 Kg) until subjects reached between 65 and 74 years of age. Fat free mass increased until 44 years of age (42.42 ± 4.17 Kg) and decreased thereafter. The prevalence of overweight/obesity significantly increased with age in the entire sample. Our results indicate that age-related increases in weight were at least partially due to increased adiposity. © 2015 Wiley Periodicals, Inc.

  19. Absolute value of bioelectrical impedance analysis-measured visceral fat area with obesity-related cardiovascular risk factors in Japanese workers.

    Science.gov (United States)

    Okauchi, Yukiyoshi; Kishida, Ken; Funahashi, Tohru; Noguchi, Midori; Ogawa, Tomoko; Ryo, Miwa; Okita, Kohei; Iwahashi, Hiromi; Imagawa, Akihisa; Nakamura, Tadashi; Matsuzawa, Yuji; Shimomura, Iichiro

    2010-12-26

    The accumulation of Visceral fat is known to precede metabolic disorders and atherosclerosis. This study aimed to determine the relationships between body mass index (BMI), waist circumference (WC), estimated visceral fat area (eVFA) measured by bioelectrical impedance analysis (BIA), and obesity-related cardiovascular risk factors. The study population was 2,870 middle-aged Japanese employees (males/females=2,322/ 548), who had undergone a health check-up. In the receiver operating characteristic (ROC) curve, the cutoff levels yielding maximal sensitivity plus specificity for predicting the prevalence of ≥ 2 risks were, 24.5 kg/m(2) for BMI, 84.6 cm for WC, and 111 cm(2) for eVFA in males, and 23.6 kg/m(2), 81.5 cm, and 67 cm(2) in females. The average number of risk factors was over 1.0 in those with a BMI ≥ 25 kg/m(2) and with a WC ≥ 85 cm for males, ≥ 28 kg/m(2) and ≥ 95 cm respectively for females, and those with an eVFA ≥ 100 cm(2) for both males and females. In males, it was around 1.0 with cutoff levels of BMI, WC, and eVFA from the ROC curve. However, in females, it was around 0.6, because the prevalence of subjects with obesity and multiple risks was very low. These results suggested that the cutoff level for visceral fat reduction should be set based on an absolute value of risk factors, rather than a calculated value. In regular health check-up, it may be useful to set an absolute cutoff value for eVFA at 100 cm(2) as criteria to screen for multiple obesity-related cardiovascular risk factors.

  20. Changes in body composition during weight loss in obese subjects in the NUGENOB study: comparison of bioelectrical impedance vs. dual-energy X-ray absorptiometry.

    Science.gov (United States)

    Verdich, C; Barbe, P; Petersen, M; Grau, K; Ward, L; Macdonald, I; Sørensen, T I A; Oppert, J-M

    2011-06-01

    We studied the accuracy of bioelectrical impedance analysis (BIA) to assess changes in body composition during moderate weight loss in obese subjects. Estimates of changes in fat mass (FM) and fat-free mass (FFM) by BIA were compared with those by dual-energy X-ray absorptiometry (DXA) as the reference method during a 10-week standardized weight-loss intervention. In obese women (age: 20-50 years, mean BMI: 33.8 kg/m(2)) participating in a European multicentre trial (nutrient-gene interactions in human obesity [NUGENOB]), body composition was assessed by BIA (Bodystat QuadScan 4000) and DXA (Lunar DPX-IQ at two centres, Hologic QDR 2000 at another centre) at baseline (n=131) and at week 10 (n=105) after a mean weight loss of -5.7 kg. At baseline, BIA significantly overestimated FFM and underestimated FM (by 1-3 kg on average) compared with DXA, and the limits of agreement were wide (mean ± 7-8.5 kg). For body-composition changes, although biases were generally non-significant, the limits of agreement were also wide (mean ± 3.7-4.6 kg). An FFM prediction equation for BIA data was developed in subjects scanned with Lunar instruments and cross-validated in an independent sample of 31 obese women undergoing similar weight loss. However, no major improvement in limits of agreement was found. During moderate diet-induced weight loss, the use of BIA leads to estimates of changes in body composition at the individual level that can differ substantially from those assessed by DXA, indicating that BIA and DXA cannot be used interchangeably. However, BIA in this context may be used for assessing changes in body composition at group level. Copyright © 2010 Elsevier Masson SAS. All rights reserved.

  1. Measurement of body composition changes during weight loss in obese men using multi-frequency bioelectrical impedance analysis and multi-compartment models.

    Science.gov (United States)

    Johnstone, Alexandra M; Faber, Peter; Gibney, Eileen R; Lobley, Gerald E; Stubbs, R James; Siervo, Mario

    2014-01-01

    The accurate measurement of changes in body composition is important to assess the contribution of fat and fat free mass to total body mass change as a measure of the effectiveness of weight loss programmes. Bioelectrical impedance spectroscopy (BIS) is a rapid and non-invasive technique which could be applied to assess body composition changes. The aim of the study was to evaluate the accuracy of the BIS for the measurement of fat mass (FM), total body water (TBW) and extracellular water (ECW) changes induced by different degrees of caloric deficit in obese men. Three groups of six, obese men participated in either (i) a total fast (for 6 days); (ii) a VLCD (2.5 MJ/day for 3 weeks); or (iii) LCD (5.2 MJ/day for 6 weeks). FM was measured using a 4-compartment (4-C) model. TBW and ECW were determined by dilution methods, respectively. TBW, ECW and FM were also assessed with BIS. Body weight loss in the fasting group was 6.0 ± 1.3 kg over 6 days; the VLCD group lost 9.2 ± 1.2 kg over 21 days and the LCD group lost 12.6 ± 2.4 kg over 42 days. BIS underestimated FM changes (bias = -3.3 ± 3.8 kg) and overestimated changes in TBW and ECW by +1.8 ± 4.8 kg and +2.3 ± 6.4 kg, respectively. The measurement error was consistently larger in the fasting group and the magnitude of the bias interacted significantly with the rate of weight loss. Rapid weight loss affects the accuracy of the BIS in detecting changes in body composition. A careful interpretation of the results is needed when sizable changes in body water compartments occurs. © 2014 Asian Oceanian Association for the Study of Obesity . Published by Elsevier Ltd. All rights reserved.

  2. Leg to leg bioelectrical impedance analysis of percentage fat mass in obese patients-Can it tell us more than we already know?

    Science.gov (United States)

    Dixon, John B; Bhasker, Aparna G; Lambert, Gavin W; Lakdawala, Muffazal

    2016-08-01

    Bioelectrical impedance analysis (BIA) is well tolerated, inexpensive, and readily available, but can it be used to detect with clinical precision aberrant changes in the proportion of fat mass to fat-free mass during weight loss? To assess the variance in percentage body fat mass explained by the readily available inputs and assess residual variance provided by leg-to-leg BIA scales. Using cross-sectional data from a cohort of 665 patients of Indian ethnicity presenting for bariatric surgery, we examine the determinants of percentage body fat as provided by leg-to-leg output from Tanita SC-330 BIA scales. Four input factors-sex, weight, height, and age-contributed to provide 92% and 95% explanation in output variance for percentage fat mass (%FM) and actual fat mass, respectively, in 665 patients. Body mass index alone explained 89% and 81% of variance in %FM output for women and men, respectively. Neither weight distribution, as indicated by waist and hip circumference or waist to hip ratio, nor plasma lipids or markers of glucose metabolism contributed additional variance in %FM when controlled for the 4 key inputs. Simple, known input variables dominate the leg-to-leg BIA output of %FM, and this may compromise the detection of aberrant changes in %FM and fat-free mass with substantial weight loss. For clinical research, validated methods not largely dependent on known inputs should be used for evaluating changes in body composition after substantial weight loss. Copyright © 2016 American Society for Bariatric Surgery. Published by Elsevier Inc. All rights reserved.

  3. Multi-frequency bioelectrical impedance analysis (BIA) compared to magnetic resonance imaging (MRI) for estimation of fat-free mass in colorectal cancer patients treated with chemotherapy.

    Science.gov (United States)

    Palle, Stine S; Møllehave, Line T; Taheri-Kadkhoda, Zahra; Johansen, Susanne; Larsen, Lisbeth; Hansen, Janne W; Jensen, Nikolaj K G; Elingaard, Anette O; Møller, Alice H; Larsen, Karen; Andersen, Jens R

    2016-12-01

    Changes in body composition in cancer patients during chemotherapy are associated with treatment related toxicities or mortalities. Thus, it is relevant to identify accessible, relatively inexpensive, portable and reliable tools for evaluation of body composition in cancer patients during the course of their treatments. To examine relationships between single cross-sectional thighs magnetic resonance imaging (MRI), skeletal muscle mass (SM) as reference and multi-frequency bioelectrical impedance analysis (BIA) fat free mass (FFM) in patients with colorectal cancer undergoing chemotherapy. In an observational, prospective study we examine the relationships between single cross-sectional thighs MRI (T1-weighted (1.5 T) SM compared to FFM BIA (8-electrodes multi-frequency Tanita MC780MA)) and FFM skin-fold thickness (ST) (4-points (Harpenden, Skinfold Caliper)) and SM equation for non-obese persons from Lee et al. 2000 (L2000) (based on age, height, weight, sex and race). FFM and SM (kg) were calculated based on either area (MRI) or weight. 18 CRC patients (10 males and 8 females) with mean (SD) age 67 yr (6) were measured at baseline, and 13 were available for follow-up. BIA overestimated FFM kg for all 31 measurements with mean (SD) 18.0 kg (6.0) compared to the MRI. ST overestimated FFM kg with mean 12.4 kg (6.2) and L2000 underestimated SM kg in 18 measurements and overestimated in 13 with a total mean of -4.3 kg (6.8). BIA and ST were the best alternatives to MRI as they showed constant and thereby correctable errors. The equation, L2000, carried the smallest average measurement error but it was non-constant. Copyright © 2016 European Society for Clinical Nutrition and Metabolism. Published by Elsevier Ltd. All rights reserved.

  4. Comparison of Abdominal Visceral Adipose Tissue Area Measured by Computed Tomography with That Estimated by Bioelectrical Impedance Analysis Method in Korean Subjects.

    Science.gov (United States)

    Lee, Dong-Hwa; Park, Kyeong Seon; Ahn, Soyeon; Ku, Eu Jeong; Jung, Kyong Yeun; Kim, Yoon Ji; Kim, Kyoung Min; Moon, Jae Hoon; Choi, Sung Hee; Park, Kyong Soo; Jang, Hak Chul; Lim, Soo

    2015-12-16

    We evaluated the concordance between visceral fat area (VFA) estimated by bioelectrical impedance analysis (BIA) or computed tomography (CT) in Korean subjects with a wide range in age and body mass index (BMI). In 1006 individuals (mean age 55.2 ± 11.8 (19-87) years, mean BMI 26.0 ± 3.5 (17-46) kg/m², 48.9% men), VFA quantified by CT was compared with VFA using multifrequency BIA machines within 15 days. Concordance rates were compared by age or BMI using correlation analysis, Bland-Altman plots, and intraclass correlation coefficient (ICC). Using BIA data, we established a regression formula to reflect CT-VFA. The mean VFAs by CT and BIA were 131.9 ± 57.3 cm² and 110.5 ± 33.9 cm², respectively (r = 0.605, p < 0.001). The mean difference was 21.4 ± 45.6 cm², tending to increase with BMI. In women with BMI <25 kg/m² or age <50 years, the VFAs by BIA were similar to those by CT (ICC = 0.496 in BMI <25 kg/m² and ICC = 0.638 in age <50 years). However, the difference was greater in men with BMI ≥25 kg/m² or age ≥50 years. Applying our formula, the difference between estimations decreased to 0.2 ± 38.2cm². VFA estimated by BIA correlated well with that by CT, but a more accurate formula is needed to match CT data, particularly in older men or subjects with a high BMI.

  5. Reliability of bioelectrical impedance analysis in the evaluation of the nutritional status of hemodialysis patients - a comparison with Mini Nutritional Assessment.

    Science.gov (United States)

    Erdoğan, E; Tutal, E; Uyar, M E; Bal, Z; Demirci, B G; Sayın, B; Sezer, S

    2013-01-01

    Protein-energy wasting (PEW) is a strong predictive factor for morbidity and mortality in patients who have end-stage renal disease (ESRD). Mini Nutritional Assessment (MNA) is an important and confirmed tool to evaluate PEW that has been recommended by many guidelines. Bioelectrical impedance analysis (BIA) is a noninvasive technique for assessing body composition. The aim of the present study was to analyze the reliability of BIA in malnutrition diagnosis by comparing it with standard MNA in a group of 100 ESRD patients. One hundred ESRD patients who were medically stable and under dialysis treatment for at least 6 months were enrolled to the study. Monthly assessed serum creatinine, albumin, C-reactive protein (CRP), and lipid profiles from the last 6 months prior to the study were retrospectively collected. A standard Full-MNA and body composition analyses were applied to all patients. Body compositions were analyzed with the BIA technique using the Body Composition Analyzer (Tanita BC-420 MA; Tanita, Tokyo, Japan). Patients were classified into three groups according to MNA scores as PEW (n = 15, score hemodialysis treatment was significantly shorter in the PEW group compared to both of the other groups described (P = .015). Well-nourished and risk groups had lower CRP and higher albumin levels compared to PEW patients; however, these values were statistically similar in these two groups (P = .018, .01, respectively). According to BIA findings, well-nourished patients had the highest fat ratio, fat mass, muscle mass, visceral fat mass, and fat-free mass compared to both moderate the PEW/risk and the PEW groups (P nutritional status of ESRD along with MNA, anthropometric measures, and classical biochemical markers. Copyright © 2013 Elsevier Inc. All rights reserved.

  6. A Comparison Study of Portable Foot-to-Foot Bioelectrical Impedance Scale to Measure Body Fat Percentage in Asian Adults and Children

    Directory of Open Access Journals (Sweden)

    Pei Ying Sim

    2014-01-01

    Full Text Available Objective. To compare the measurements of body fat percentage (BF% using the foot-to-foot bioelectrical impedance analysis (FTF-BIA with the direct segmental multifrequency BIA (DSM-BIA. Methods. There were 36 men and 52 women (37.1±14.3 years with 57% Malays, 30% Chinese, and 13% Indian. For children, there were 45 boys and 26 girls (11.5±2.5 years with 52% Malay, 15% Chinese, and 33% Indian. Results. Mean height for men was 168.4 cm, 11 cm taller than women. Men were 10 kg heavier than women at 70 kg. BF% in women was 32% and 33% whereas BF% in men was 23% and 25% when measured using FTF-BIA and DSM-BIA, respectively. In children, BF% measured with FTF-BIA and DSM-BIA was 49% and 46%, respectively. The correlations were significant for men (r=0.92, SEE = 2.80, women (r=0.91, SEE = 3.31, boys (r=0.95, SEE = 5.44, and girls (r=0.96, SEE = 5.27. The BF% in underweight/normal (r=0.92, SEE = 2.47 and that in overweight/obese adults (r=0.89, SEE = 3.61 were strongly correlated. The correlations were significant in normal/underweight (r=0.94, SEE = 3.78 and obese/overweight children (r=0.83, SEE = 6.49. All ethnic groups showed significant correlation with BF%. Malay adults (r=0.92, SEE = 3.27 and children (r=0.94, SEE = 0.88 showed significant mean differences in BF%. Conclusion. The FTF-BIA showed higher accuracy for all normal/underweight and Chinese group with acceptable overestimation in children and underestimation in adults. Caution should be taken when interpreting BF% depending on gender, BMI, and ethnicity.

  7. Cross-mode bioelectrical impedance analysis in a standing position for estimating fat-free mass validated against dual-energy x-ray absorptiometry.

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    Huang, Ai-Chun; Chen, Yu-Yawn; Chuang, Chih-Lin; Chiang, Li-Ming; Lu, Hsueh-Kuan; Lin, Hung-Chi; Chen, Kuen-Tsann; Hsiao, An-Chi; Hsieh, Kuen-Chang

    2015-11-01

    Bioelectrical impedance analysis (BIA) is commonly used to assess body composition. Cross-mode (left hand to right foot, Z(CR)) BIA presumably uses the longest current path in the human body, which may generate better results when estimating fat-free mass (FFM). We compared the cross-mode with the hand-to-foot mode (right hand to right foot, Z(HF)) using dual-energy x-ray absorptiometry (DXA) as the reference. We hypothesized that when comparing anthropometric parameters using stepwise regression analysis, the impedance value from the cross-mode analysis would have better prediction accuracy than that from the hand-to-foot mode analysis. We studied 264 men and 232 women (mean ages, 32.19 ± 14.95 and 34.51 ± 14.96 years, respectively; mean body mass indexes, 24.54 ± 3.74 and 23.44 ± 4.61 kg/m2, respectively). The DXA-measured FFMs in men and women were 58.85 ± 8.15 and 40.48 ± 5.64 kg, respectively. Multiple stepwise linear regression analyses were performed to construct sex-specific FFM equations. The correlations of FFM measured by DXA vs. FFM from hand-to-foot mode and estimated FFM by cross-mode were 0.85 and 0.86 in women, with standard errors of estimate of 2.96 and 2.92 kg, respectively. In men, they were 0.91 and 0.91, with standard errors of the estimates of 3.34 and 3.48 kg, respectively. Bland-Altman plots showed limits of agreement of -6.78 to 6.78 kg for FFM from hand-to-foot mode and -7.06 to 7.06 kg for estimated FFM by cross-mode for men, and -5.91 to 5.91 and -5.84 to 5.84 kg, respectively, for women. Paired t tests showed no significant differences between the 2 modes (P > .05). Hence, cross-mode BIA appears to represent a reasonable and practical application for assessing FFM in Chinese populations. Copyright © 2015 Elsevier Inc. All rights reserved.

  8. Evaluation of volume overload by bioelectrical impedance analysis, NT-proBNP and inferior vena cava diameter in patients with stage 3&4 and 5 chronic kidney disease.

    Science.gov (United States)

    Yilmaz, Zülfükar; Yildirim, Yaşar; Oto, Ferhat; Aydin, Fatma Yilmaz; Aydin, Emre; Kadiroglu, Ali Kemal; Yilmaz, Mehmet Emin

    2014-05-01

    Determination of fluid overload is important in chronic kidney disease. Early diagnosis and treatment of volume overload may decrease morbidity and mortality. We aimed to determine body composition by using bioelectrical impedance analysis, and studying other clinical characteristics, inferior vena cava diameter, and N-terminal pro-B natriuretic peptide associated with hydration status in chronic kidney disease Stages 3&4 and 5 in patients not undergoing dialysis. We examined 62 patients with Stages 3&4 and 68 patients with Stage 5 chronic kidney disease. Plasma NT-proBNP was measured and analyzed after log transformation. Inferior vena cave diameter was measured with echocardiography and indexed for body surface area. Hydration status was assessed using multi-frequency bioelectrical impedance analysis. Overhydration was defined as overhydration/extracellular water >0.15. Overhydration was more frequent in Stage 5 than in Stages 3&4 patients. Systolic and diastolic blood pressure, inferior vena cava index, and log NT-proBNP were higher in overhydrated compared to non-overhydrated patients. A significant positive correlation existed between overhydration/extracellular water and log NT-proBNP, systolic and diastolic blood pressures, and inferior vena cava index. In multiple linear regression analysis, the variables associated with hydration status were male sex, extracellular water/total body water, and extracellular water/intracellular water (greater overhydration), while serum albumin levels had a negative association with overhydration. Overhydration is more prevalent in Stage 5 chronic kidney disease patients than in Stages 3&4 patients. Bioelectrical impedance analysis, inferior vena cava diameter, and NT-proBNP analysis in chronic kidney disease are useful methods to determine the volume overload.

  9. Relationship between water compartments, body composition assessed by bioelectrical impedance analysis and blood pressure in school children.

    Science.gov (United States)

    Łątka, Monika; Wójtowicz, Kinga; Drożdż, Tomasz; Dąbrowska, Ewelina; Kwinta, Przemko; Pietrzyk, Jacek Antoni; Drożdż, Dorota

    2016-01-01

    Electrical bioimpedance analysis (BIA) is becoming more widely used in clinical practice as a method of body composition analysis. In healthy children blood pressure (BP) changes with age, body mass and height. Until now the relation between water compartments and BP in healthy children has not been evaluated. The aim of this study was to evaluate the relationship between body composition as well as water compartments (measured by electrical bioimpedance) and BP. The study was performed in 72 children (32 girls and 40 boys) aged: 6-7 and 12-13 years. BIA measurements were taken using Nutriguard Data Input device with Bianostic electrodes and following parameters were calculated: total body water (TBW), lean body mass (LBM), fat mass (FM), intra- and extracellular water (ICW, ECW) and phase angle alpha. BP was measured twice using the oscillometric method. Elevated BP > 95th percentile for gender, age and height were observed in 9 children. A significant correlation between systolic (S)BP and TBW (R = 0.4023, p obesity (BMI > 95th percentile). Growth disorders were found in 6 children (5 of them being undernourished). In the studied children SBP and DBP correlated with water compartments, lean body and fat masses derived from BIA. The problem of unrecognized hypertension and malnutrition in children and adolescents is still underestimated in the Polish population.

  10. Does the presence of an arteriovenous fistula alter changes in body water following hemodialysis as determined by multifrequency bioelectrical impedance assessment?

    Science.gov (United States)

    Panorchan, Kwanpeemai; Nongnuch, Arkom; El-Kateb, Sally; Goodlad, Cate; Davenport, Andrew

    2015-10-01

    Multifrequency bioelectrical impedance assessments (MFBIAs) aid clinical assessment of hydration status for hemodialysis (HD) patients. Many MFBIA devices are restricted to whole body measurements and as many patients dialyze using arteriovenous fistulas (AVFs), we wished to determine whether AVFs affected body water measurements. We reviewed pre- and post-HD segmental MFBIA measurements in 229 patients attending for midweek HD sessions. Up to 144 were dialyzed with a left arm AVF (L-AVF), 42 with a right arm AVF (R-AVF), and 43 by central venous access catheter (CVC). Water content and lean tissue were greater in the left compared to right arm in those patients with L-AVFs both pre and post dialysis (pre 2.1 ± 0.7 vs. 2.0 ± 0.7 L, and post 1.9 ± 0.6 vs. 1.8 ± 0.6 L and pre 2.65 ± 0.9 vs. 2.56 ± 0.8 kg, and post 2.34 ± 0.8 vs. 2.48 ± 0.8 vs. 2.34 ± 0.8 kg, respectively) and were also greater in the right compared to left arm for those patients dialyzing with R-AVFs (pre-HD 1.92 ± 0.5 vs. 1.86 ± 0.6 L and post-HD 1.79 ± 0.5 vs. 1.7 ± 0.5 L, and pre-HD 2.47 ± 0.6 vs. 2.38 ± 0.7 kg and post-HD 2.3 ± 0.74 vs. 1.28 ± 0.7 kg, respectively), all Ps Hemodialysis.

  11. Randomized trial of bioelectrical impedance analysis versus clinical criteria for guiding ultrafiltration in hemodialysis patients: effects on blood pressure, hydration status, and arterial stiffness.

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    Onofriescu, Mihai; Mardare, Nicoleta Genoveva; Segall, Liviu; Voroneanu, Luminiţa; Cuşai, Claudiu; Hogaş, Simona; Ardeleanu, Serban; Nistor, Ionuţ; Prisadă, Octavian Viorel; Sascău, Radu; Covic, Adrian

    2012-04-01

    Chronic fluid overload is common in maintenance hemodialysis (HD) patients and is associated with severe cardiovascular complications, such as arterial hypertension, left ventricular hypertrophy, congestive heart failure, and arrhythmia. Therefore, a crucial target of HD is to achieve the so-called dry weight; however, the best way to assess fluid status and dry weight is still unclear. Dry weight is currently determined in most dialysis units on a clinical basis, and it is commonly defined as the lowest body weight a patient can tolerate without developing intra-dialytic or inter-dialytic hypotension or other symptoms of dehydration. One of the most promising methods that have emerged in recent years is bioelectrical impedance analysis (BIA), which estimates body composition, including hydration status, by measuring the body's resistance and reactance to electrical current. Our objective was to study the effect BIA-guided versus clinical-guided ultrafiltration on various cardiovascular disease risk factors and markers in HD patients. We included 135 HD patients from a single center in a prospective study, aiming to compare the long-term (12 months) effect of BIA-based versus clinical-based assessment of dry weight on blood pressure (BP), pulse wave velocity (PWV), and serum N-terminal fragment of B-type natriuretic peptide (NT-proBNP). The body composition was measured using the portable whole-body multifrequency BIA device, Body Composition Monitor-BCM(®) (Fresenius Medical Care, Bad Homburg, Germany). In the "clinical" group there were no changes in BP, body mass index (BMI), and body fluids. The PWV increased from 7.9 ± 2.5 to 9.2 ± 3.6 m/s (P = 0.002), whereas serum NT-proBNP decreased from 5,238 to 3,883 pg/ml (P = 0.05). In the "BIA" group, BMI and body volumes also did not change; however, there was a significant decrease in both systolic BP, from 144.6 ± 14.7 to 135.3 ± 17.8 mmHg (P < 0.001), and diastolic BP, from 79.5 ± 9.7 to 73.2 ± 11.1 mmHg (P

  12. Fluid management in the intensive care unit: bioelectrical impedance vector analysis as a tool to assess hydration status and optimal fluid balance in critically ill patients.

    Science.gov (United States)

    Basso, Flavio; Berdin, Giovanna; Virzì, Grazia Maria; Mason, Giacomo; Piccinni, Pasquale; Day, Sonya; Cruz, Dinna N; Wjewodzka, Marzena; Giuliani, Anna; Brendolan, Alessandra; Ronco, Claudio

    2013-01-01

    Fluid balance disorders are a relevant risk factor for morbidity and mortality in critically ill patients. Volume assessment in the intensive care unit (ICU) is thus of great importance, but there are currently few methods to obtain an accurate and timely assessment of hydration status. Our aim was to evaluate the hydration status of ICU patients via bioelectric impedance vector analysis (BIVA) and to investigate the relationship between hydration and mortality. We evaluated 280 BIVA measurements of 64 patients performed daily in the 5 days following their ICU admission. The observation period ranged from a minimum of 72 h up to a maximum of 120 h. We observed the evolution of the hydration status during the ICU stay in this population, and analyzed the relationship between mean and maximum hydration reached and mortality--both in the ICU and at 60 days--using logistic regression. A state of overhydration was observed in the majority of patients (70%) on admission, which persisted during the ICU stay. Patients who required continuous renal replacement therapy (CRRT) were more likely to be overhydrated starting from the 2nd day of observation. Logistic regression showed a strong and significant correlation between mean/maximum hydration reached and mortality, both independently and correcting for severity of prognosis. Fluid overload measured by BIVA is a frequent condition in critically ill patients--whether or not they undergo CRRT--and a significant predictor of mortality. Hence, hydration status should be considered as an additional prognosticator in the clinical management of the critically ill patient. (i) On the day of ICU admittance, patients showed a marked tendency to overhydration (>70% of total). This tendency was more pronounced in patients on CRRT. (ii) Hyperhydration persisted during the ICU stay. Patients who underwent CRRT showed significantly higher hyperhydration from the 2nd day of hospitalization. (iii) Nonsurvivors showed worse hyperhydration

  13. [Analysis of metabolic syndrome and pulse wave velocity in hemodialysis patients: diagnosis of obesity by bioelectrical impedance analysis and a novel risk factor for atherosclerosis].

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    Sasaki, Nobuhiro; Takeda, Shinichi; Saito, Takako; Ando, Yasuhiro; Kusano, Eiji

    2009-01-01

    Metabolic syndrome (Met S) is one of the risk factors of atherosclerotic vascular diseases related to visceral fat accumulation. However, it is well known that morbidity and mortality of hemodialysis (HD) patients are associated with malnutrition and emaciation rather than obesity, representing "reverse epidemiology". The risk of visceral fat accumulation or Met S in HD patients remains unclear. Therefore, we evaluated atherosclerosis and Met S in HD patients using various markers of obesity by means of bioelectrical impedance analysis (BIA) and brachial-ankle PWV(baPWV). The subjects comprised 52 patients who were undergoing maintenance dialysis. In addition to a general physical examination and routine blood tests, immunoreactive insulin (IRI), homeostasis model assessment for insulin resistance (HOMA-R), serum adiponectin (ADPN) and C-reactive protein (CRP)were measured before dialysis. Furthermore, we measured various body fluid components, such as the ratio of extracellular water to total body water (ECW/TBW), body fat mass (BFM), percent body fat(PBF) and visceral fat accumulation (BIA-VFA), using a body composition analyzer (InBody S20)and baPWV as a marker of atherosclerosis. There was no significant difference between HD patients with and without Met S for baPWV. baPWV was positively correlated with age, systolic BP and ECW/TBW, and negatively correlated with serum albumin level, BMI and serum ADPN. However, no significant correlations were observed between baPWV and the durations of HD, Ca x P product, BIA-VFA, PBF, HOMA-R and CRP. The serum ADPN level was significantly lower in Met S than in non-Met S. In addition, the ADPN level was positively correlated with HDL-cholesterol, and negatively correlated with TG, HbA1c, CRP and various markers of obesity (Waist, BIA-VFA, BFM and PBF). In a multiple regression analysis for baPWV, the ECW/TBW ratio and serum ADPN level, as well as age and systolic BP, were independent predictors for the enhancement of ba

  14. [Comparison whole-body muscle mass assessed by dual-energy X-ray absorptiometry and multi-frequency bioelectrical impedance in overweight and obese adults].

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    Wang, Z H; Dong, Y H; Yang, Y D; Wang, S; Ma, J

    2017-03-06

    Objective: To investigate consistency of whole-body muscle mass (WBMM) assessed using multi-frequency bioelectrical impedance analysis (MF-BIA) and dual energy X-ray Absorptiometry (DXA) measurement, and to delvelop the correction regression formulas for the method of MF-BIA. Methods: 1 488 participants who resided in Beijing longer than one year, under 22 to 55 years of age, with self-report BMI ≥24 kg/m(2) were voluntarily recruited based on convenience sampling in Beijing, from April 1(st) 2014 to May 2(nd) 2014. After excluded 171 participants who BMI ≤24 kg/m(2) or with organic diseases when physical examination, Finally 1 317 overweight/obese participants were enrolled into the current study. All the subjects received the measurement of WBMM using both MF-BIA and DXA methods. The paired-samples T test was used to compare the difference of measurement values between MF-BIA and DXA methods. We evaluated the agreement of WBMM measured by MF-BIA and DXA using the interclass correlation coefficients (ICC) and the Bland-Altman plots, and using linear regression method established correction regression formulas. Results: The differences of overweight male, obese male, overweight female, and obese female were (3.29 ± 1.94), (2.05 ± 2.65), (0.17 ± 1.85), and (-2.22 ± 2.89) kg between methods of MF-BIA and DXA, respectively; Except the overweight female, the others groups had the statistically significant difference ( Pobese male, overweight female, and obese female were 0.958, 0.956, 0.911, and 0.851, respectively ( Pobese male population: y (DXA)=-3.646 + 1.026 x (MF-BIA); overweight female groups: y (DXA)=-4.800 + 1.117 x (MF-BIA); obese female group: y (DXA)=-9.884+ 1.287 x (MF-BIA). Conclusion: The correlation and agreement of WBMM measured by the methods of BIA and DXA were relative weak in Chinese excess weight male and obese female adults. Therefore, measuring WBMM by MF-BIA method in these adults should be corrected to reduce bias compared with the DXA

  15. Comparison of segmental multifrequency bioelectrical impedance analysis with dual-energy X-ray absorptiometry for the assessment of body composition in a community-dwelling older population.

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    Kim, Miji; Shinkai, Shoji; Murayama, Hiroshi; Mori, Seijiro

    2015-08-01

    The purpose of the present study was to examine the agreement of segmental multifrequency bioelectrical impedance analysis (SMF-BIA) for the assessment of whole-body and appendicular fat mass (FM) and lean soft tissue mass (LSTM) compared with dual-energy X-ray absorptiometry (DXA) in a community-dwelling Japanese older population. The study population included 551 community-dwelling Japanese older adults (241 men and 310 women) aged between 65 and 87 years. Agreement between SMF-BIA and DXA for whole-body and appendicular body composition was assessed using simple linear regression and Bland-Altman analysis. High coefficients of determination (R(2)) were observed for whole-body FM (R(2) = 0.91, standard error of estimate [SEE] = 1.4 kg in men and R(2) = 0.94, SEE = 1.2 kg in women) between SMF-BIA and DXA. The R(2) coefficient for whole-body LSTM was higher in men (R(2) = 0.88, SEE = 1.9 kg) than in women (R(2) = 0.83, SEE = 1.5 kg). There was systematic bias with overestimation of whole-body FM and underestimation of whole-body LSTM by SMF-BIA. Proportional bias was noted for measurement of whole-body FM and LSTM in both men and women, but there was no proportional bias between the two methods for measurement of appendicular LSTM (r = 0.05, P = 0.428 and r = -0.10, P = 0.070 for men and women, respectively). SMF-BIA is a good alternative for estimating the whole-body and appendicular FM and LSTM in a community-dwelling Japanese older population, although it overestimated FM and underestimated LSTM when validated against DXA. © 2014 Japan Geriatrics Society.

  16. Bioelectrical Impedance Analysis (BIA) of the association of the Japanese Kampo concept "Suidoku" (fluid disturbance) and the body composition of women.

    Science.gov (United States)

    Murakami, Aya; Kobayashi, Daisuke; Kubota, Toshio; Zukeyama, Niina; Mukae, Haru; Furusyo, Norihiro; Kainuma, Mosaburo; Shimazoe, Takao

    2016-10-22

    In Japanese Kampo medical practice, suidoku (fluid disturbance) is one of the most important concepts for selecting the proper medication. Suidoku is an excessive or uneven distribution of fluid that is indicated by splashing sounds and pitting edema. However, few objective reports about suidoku have been published. Bioelectrical impedance analysis (BIA) uses resistance values obtained from weak electrical currents to estimate body composition, including intracellular and extracellular water and muscle and fat mass. In this study, we used BIA to search for objective factors that can discriminate the various types of suidoku. Two hundred twenty-nine patients who visited the Kampo Medicine Clinic of Kyushu University Hospital from June 2010 to August 2015 were divided into non-suidoku (n = 180, 80 male and 100 female), splashing sound (n = 32, 8 male and 24 female) and edema groups (n = 17, 5 male and 12 female). Body composition values were taken from the electronic medical records of InBody730 (a vertical, segmental, multi-frequency analyzer by InBody, Tokyo Japan) testing done at the initial visit. Various parameters of the body composition values of female in the non-suidoku and suidoku groups (splashing sound and edema groups) were compared: there were too few male patients to provide significance. The age and body weight were significantly lower in the splashing sound group than in the non-suidoku group (p < 0.05). In contrast, the body weight of the edema group was significantly heavier than that of the non-suidoku group (p < 0.05). In ROC analysis, the percent Body Fat ≤ 27.8 %, Muscle Mass Index of the Trunk ≤ 6.5 kg/m 2 , VFA (Visceral fat area) ≤ 5.4 and BMI ≤ 19.2 kg/m 2 were associated with splashing sound, and Muscle Mass Index of Legs ≥ 4.8 kg/m 2 and BMI ≥ 21.4 kg/m 2 were associated with edema. Our data suggest that the use of this type of BIA to estimate body composition would be a useful

  17. Impact of hyperhydration on the mortality risk in critically ill patients admitted in intensive care units: comparison between bioelectrical impedance vector analysis and cumulative fluid balance recording.

    Science.gov (United States)

    Samoni, Sara; Vigo, Valentina; Reséndiz, Luis Ignacio Bonilla; Villa, Gianluca; De Rosa, Silvia; Nalesso, Federico; Ferrari, Fiorenza; Meola, Mario; Brendolan, Alessandra; Malacarne, Paolo; Forfori, Francesco; Bonato, Raffaele; Donadio, Carlo; Ronco, Claudio

    2016-04-08

    Studies have demonstrated a positive correlation between fluid overload (FO) and adverse outcomes in critically ill patients. The present study aims at defining the impact of hyperhydration on the Intensive Care Unit (ICU) mortality risk, comparing Bioelectrical Impedance Vector Analysis (BIVA) assessment with cumulative fluid balance (CFB) recording. We performed a prospective, dual-centre, clinician-blinded, observational study of consecutive patients admitted to ICU with an expected length of ICU stay of at least 72 hours. During observational period (72-120 hours), CFB was recorded and cumulative FO was calculated. At the admission and daily during the observational period, BIVA was performed. We considered FO between 5% and 9.99% as moderate and a FO ≥ 10% as severe. According to BIVA hydration scale of lean body mass, patients were classified as normohydrated (>72.7%-74.3%), mild (>71%-72.7%), moderate (>69%-71%) and severe (≤ 69%) dehydrated and mild (>74.3%-81%), moderate (>81%-87%) and severe (>87%) hyperhydrated. Two multivariate logistic regression models were performed: the ICU mortality was the response variable, while the predictor variables were hyperhydration, measured by BIVA (BIVA model), and FO (FO model). A p-value <0.05 was considered to indicate statistical significance. One hundred and twenty-five patients were enrolled (mean age 64.8 ± 16.0 years, 65.6% male). Five hundred and fifteen BIVA measurements were performed. The mean CFB recorded at the end of the observational period was 2.7 ± 4.1 L, while the maximum hydration of lean body mass estimated by BIVA was 83.67 ± 6.39%. Severe hyperhydration measured by BIVA was the only variable found to be significantly associated with ICU mortality (OR 22.91; 95% CI 2.38-220.07; p < 0.01). The hydration status measured by BIVA seems to predict mortality risk in ICU patients better than the conventional method of fluid balance recording. Moreover, it appears to be safe, easy to use and

  18. Study of cystatin C (Cys C in relation to the calculation of the glomerular filtration rate and bioelectrical impedance analysis parameters in obese patients with and without type 2 diabetes

    Directory of Open Access Journals (Sweden)

    Mario Liani

    2012-01-01

    Full Text Available IntroductionAssessment of renal function based on quantification of the glomerular filtration rate (GFR is essential for early detection of damage and progression of renal diseases. The purpose of our study was to determine the value of cystatin C (Cys C assays in the calculation of the GFR and bioelectrical impedance analysis parameters in obese subjects aged 30-70 years with moderately damaged renal function.Materials and methodsCys C levels were measured with a new immunoturbidimetric kit (Roche Diagnostics and an automated Cobas c6000 analyzer. In the GFR calculation, creatinine and Cys C levels were included. The GFR calculated with the equation that included Cys C in obese and normal-weight patients is not affected by changes in the lean body mass.ResultsObese patients (N = 70 had a mean (± SD serum creatinine level of 1.52 ± 1.0 mg/dL and a mean Cys C level of 1.28 ± 0.59 mg/L. In this group, the GFR calculated on the basis of MDRD, Cys C, and creatinine clearance values showed similar filtered values between MDRD and Cys C and a DS value smaller in the case of Cys C. The correlation (R2 between GFR and its metabolite is higher in the case of Cys C when somatotype parameters (measured with bioelectrical impedance analysis were introduced into the equation.ConclusionsWhen Cys C is included in calculations of GFR, the result shows a higher correlation degree compared to the MDRD system. Given that Cys C shows less intra-individual variability than creatinine, it can be applied in routine diagnostics in a larger number of patients.

  19. Age- and sex-standardised lean and fat indices derived from bioelectrical impedance analysis for ages 7-11 years: functional associations with cardio-respiratory fitness and grip strength.

    Science.gov (United States)

    Sherriff, Andrea; Wright, Charlotte M; Reilly, John J; McColl, John; Ness, Andy; Emmett, Pauline

    2009-06-01

    Indices for lean and fat mass adjusted for height derived from bioelectrical impedance for children aged 7 years have been published previously and their usefulness in the clinical assessment of undernutrition has been demonstrated. However, there is a need for norms that cover a wider age range and to explore their functional significance. The aim of the present study is to derive lean and fat indices for children aged 7-11 years and investigate associations with objective measures of cardio-respiratory fitness and grip strength. Subjects were 9574 children participating in the Avon Longitudinal Study of Parents and Children (ALSPAC). Bioelectrical impedance analysis (BIA) data collected longitudinally between ages 7 and 11 were used to derive lean and fat indices using the method of standardised residuals. Cardio-respiratory fitness (CRF) (9 years) and grip strength (11 years) were also measured. Correlation coefficients and 95 % CI were calculated to assess the strength of association between lean index, fat index and CRF and grip strength. Equations for calculating lean and fat indices in children aged 7-11 years relative to the ALSPAC population are presented. Lean index was linearly associated with CRF (rboys 0.20 (95 % CI 0.15, 0.25), rgirls 0.26 (95 % CI 0.22, 0.30)) and grip strength (rboys 0.29 (95 % CI 0.26, 0.32), rgirls 0.26 (95 % CI 0.23, 0.29)). BMI showed slightly weaker associations, while fat index was unrelated to either CRF or grip strength. Lean indices relate to muscle function and fitness while fat index does not.

  20. Validation of Standing Wave Liner Impedance Measurement Method, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Hersh Acoustical Engineering, Inc. proposes to establish the feasibility and practicality of using the Standing Wave Method (SWM) to measure the impedance of...

  1. Phase dependent impedance and temperature dependent response of microwave SQUID

    International Nuclear Information System (INIS)

    Callegari, A.C.

    1978-01-01

    We report measurements of the microwave impedance of superconducting point contacts as a function of the quantum mechanical phase difference phi. They yield a conductance of the form G(phi) = G/sub o/(1+alpha cos phi) where alpha is a dimensionless parameter reflecting an interference between the Cooper pairs and the quasiparticles. Experimental results agree with a negative alpha approximately equal to -.5 which can be interpreted in terms of a phenomenological model that follows essentially the Time Dependent Landau Ginzburg theory (TDLG). In the second part we report measurements of the response of a microwave SQUID using a Ta point contact at various temperatures. They give a progression of operating conditions from the non-hysteretic to the hysteretic mode. The responses calculated by Soerensen and by Burhman and Jackel are in qualitative agreement with the measurements. We also present a theory based on a calculation of the reflection coefficient from the point contact. This theory reproduces the results of Bunhman and Jackel and Soerensen and is directly adaptable to our microwave geometry. In the last chapter we present a calculation that exhibits explicitly the dependence of the response on OMEGA = PHI/sub o/nu/I/sub X sub/R where nu is the microwave frequency, I/sub c/ and R the critical current and resistance of the junction and PHI/sub o/ fluxoid quantum, and that agrees with their data and their interpretation of it in terms of a limiting time tau for the supercurrent response with tau varies as DELTA(T)/sup -1/ where DELTA (T) is the BCS gap parameter

  2. Bioelectrical impedance analysis to estimate body composition, and change in adiposity, in overweight and obese adolescents: comparison with dual-energy x-ray absorptiometry.

    Science.gov (United States)

    Wan, Ching S; Ward, Leigh C; Halim, Jocelyn; Gow, Megan L; Ho, Mandy; Briody, Julie N; Leung, Kelvin; Cowell, Chris T; Garnett, Sarah P

    2014-10-03

    There is a need for a practical, inexpensive method to assess body composition in obese adolescents. This study aimed to 1) compare body composition parameters estimated by a stand-on, multi-frequency bioelectrical impendence (BIA) device, using a) the manufacturers' equations, and b) published and derived equations with body composition measured by dual-energy x-ray absorptiometry (DXA) and 2) assess percentage body fat (%BF) change after a weight loss intervention. Participants were 66 obese adolescents, mean age (SD) 12.9 (2.0) years. Body composition was measured by Tanita BIA MC-180MA (Tanita BIA8) and DXA (GE-Lunar Prodigy). BIA resistance and reactance data at frequencies of 5, 50, 250 and 500 kHz, were used in published equations, and to generate a new prediction equation for fat-free mass (FFM) using a split-sample method. Approximately half (n = 34) of the adolescents had their body composition measured by DXA and BIA on two occasions, three to nine months apart. The correlations between FFM (kg), fat mass (kg) and %BF measured by BIA and DXA were 0.92, 0.93 and 0.78, respectively. The Tanita BIA8 manufacturers equations significantly (P obese adolescent.

  3. Change in fat-free mass assessed by bioelectrical impedance, total body potassium and dual energy X-ray absorptiometry during prolonged weight loss

    DEFF Research Database (Denmark)

    Hendel, H W; Gotfredsen, A; Højgaard, L

    1996-01-01

    . The results of the BIA equations varied widely; FFM was generally overestimated by BIA as compared with DXA and TBK before and after weight loss. During weight loss, the FFM did not change, as estimated by DXA (1.3 +/- 2.3 kg, p > 0.05) and TBK (0.9 +/- 2.9 kg, p > 0.05). The recorded change in impedance (R...

  4. Usefulness of combining admission brain natriuretic peptide (BNP) plus hospital discharge bioelectrical impedance vector analysis (BIVA) in predicting 90 days cardiovascular mortality in patients with acute heart failure.

    Science.gov (United States)

    Santarelli, Simona; Russo, Veronica; Lalle, Irene; De Berardinis, Benedetta; Navarin, Silvia; Magrini, Laura; Piccoli, Antonio; Codognotto, Marta; Castello, Luigi Maria; Avanzi, Gian Carlo; Villacorta, Humberto; Precht, Bernardo Luiz Campanário; de Araújo Porto, Pilar Barreto; Villacorta, Aline Sterque; Di Somma, Salvatore

    2017-06-01

    Heart failure is a disease characterized by high prevalence and mortality, and frequent rehospitalizations. The aim of this study is to investigate the prognostic power of combining brain natriuretic peptide (BNP) and congestion status detected by bioelectrical impedance vector analysis (BIVA) in acute heart failure patients. This is an observational, prospective, and a multicentre study. BNP assessment was measured upon hospital arrival, while BIVA analysis was obtained at the time of discharge. Cardiovascular deaths were evaluated at 90 days by a follow up phone call. 292 patients were enrolled. Compared to survivors, BNP was higher in the non-survivors group (mean value 838 vs 515 pg/ml, p failure patients, higher BNP levels upon hospital admission, and congestion detected by BIVA at discharge have a significant predictive value for 90 days cardiovascular mortality. The combined use of admission BNP and BIVA discharge seems to be a useful tool for increasing prognostic power in these patients.

  5. Assessing Body Fat of Children by Skinfold Thickness, Bioelectrical Impedance Analysis, and Dual-Energy X-Ray Absorptiometry: A Validation Study Among Malay Children Aged 7 to 11 Years.

    Science.gov (United States)

    Noradilah, Mohd Jonit; Ang, Yeow Nyin; Kamaruddin, Nor Azmi; Deurenberg, Paul; Ismail, Mohd Noor; Poh, Bee Koon

    2016-07-01

    This study aims to validate skinfold (SKF) and bioelectrical impedance analysis (BIA) against dual-energy X-ray absorptiometry (DXA) in determining body fat percentage (BF%) of Malay children aged 7 to 11 years. A total of 160 children had their BF% assessed using SKF and BIA, with DXA as the criterion method. Four SKF equations (SKFBray, SKFJohnston, SKFSlaughter, and SKFGoran) and 4 BIA equations (BIAManufacturer, BIAHoutkooper, BIARush, and BIAKushner) were used to estimate BF%. Mean age, weight, and height were 9.4 ± 1.1years, 30.5 ± 9.9 kg, and 131.3 ± 8.4 cm. All equations significantly underestimated BF% (P < .05). BIA equations had reasonable agreement with DXA and were independent of BF% with BIAManufacturer being the best equation. Although BIA underestimates BF% as compared with DXA, BIA was more suitable to measure BF% in a population that is similar to this study sample than SKF, suggesting a need to develop new SKF equations that are population specific. © 2016 APJPH.

  6. Neck electrical impedance for measurement of swallowing; Enge katsudo no keisoku no tame no keibu denki impedance

    Energy Technology Data Exchange (ETDEWEB)

    Yamamoto, Y. [Okayama University, Okayama (Japan)] Nakamura, T. [Okayama University, Okayama (Japan). School of Health Science; Utsunomiya, K.; Akashi, K. [Kawasaki Medical School, Kawasaki (Japan)] Jikuya, K. [Kawasaki College of Allied Health Professions, Kawasaki (Japan)

    1998-03-01

    Recently videofluorography has been used for evaluation of swallowing function in rehabilitation field. But it is not easy to evaluate swallowing disorder simply. And it has problems or exposure for daily use. We have proposed a measurement method of swallowing using bioelectrical impedance method (Impedance Pharyngography, IPG) which has advantages of easy handle and non-invasive measurement. Appropriate electrode positions have been determined. The waveform of IPG can be obtained with some extent reproducibility. The change of neck electrical impedance in pharyngeal phase is mainly caused by the changes of equivalent cross sectional area of near epiglottis. The possibilities of applications for clinical diagnosis have been shown. 7 refs., 10 figs.

  7. Estimation of Human Ankle Impedance During the Stance Phase of Walking

    Science.gov (United States)

    Rouse, Elliott J.; Hargrove, Levi J.; Perreault, Eric J.; Kuiken, Todd A.

    2018-01-01

    Human joint impedance is the dynamic relationship between the differential change in the position of a perturbed joint and the corresponding response torque; it is a fundamental property that governs how humans interact with their environments. It is critical to characterize ankle impedance during the stance phase of walking to elucidate how ankle impedance is regulated during locomotion, as well as provide the foundation for future development of natural, biomimetic powered prostheses and their control systems. In this study, ankle impedance was estimated using a model consisting of stiffness, damping and inertia. Ankle torque was well described by the model, accounting for 98 ± 1.2% of the variance. When averaged across subjects, the stiffness component of impedance was found to increase linearly from 1.5 Nm/rad/kg to 6.5 Nm/rad/kg between 20% and 70% of stance phase. The damping component was found to be statistically greater than zero only for the estimate at 70% of stance phase, with a value of 0.03 Nms/rad/kg. The slope of the ankle’s torque-angle curve—known as the quasi-stiffness—was not statistically different from the ankle stiffness values, and showed remarkable similarity. Finally, using the estimated impedance, the specifications for a biomimetic powered ankle prosthesis were introduced that would accurately emulate human ankle impedance during locomotion. PMID:24760937

  8. Electrical impedance tomography spectroscopy method for characterising particles in solid-liquid phase

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Yanlin [Department of Thermal Energy Engineering, College of Mechanical and Transportation Engineering, China University of Petroleum, Beijing, 102249 (China); Wang, Mi [Institute of Particle Science and Engineering, School of Process, Environmental and Materials Engineering, University of Leeds, Leeds LS2 9JT (China); Yao, Jun [School of Energy Research, Xiamen University, Xiamen 361005 (China)

    2014-04-11

    Electrical impedance tomography (EIT) is one of the process tomography techniques to provide an on-line non-invasive imaging for multiphase flow measurement. With EIT measurements, the images of impedance real part, impedance imaginary part, phase angle, and magnitude can be obtained. However, most of the applications of EIT in the process industries rely on the conductivity difference between two phases in fluids to obtain the concentration profiles. It is not common to use the imaginary part or phase angle due to the dominant change in conductivity or complication in the use of other impedance information. In a solid-liquid two phases system involving nano- or submicro-particles, characterisation of particles (e.g. particle size and concentration) have to rely on the measurement of impedance phase angle or imaginary part. Particles in a solution usually have an electrical double layer associated with their surfaces and can form an induced electrical dipole moment due to the polarization of the electrical double layer under the influence of an alternating electric field. Similar to EIT, electrical impedance spectroscopy (EIS) measurement can record the electrical impedance data, including impedance real part, imaginary part and phase angle (θ), which are caused by the polarization of the electrical double layer. These impedance data are related to the particle characteristics e.g. particle size, particle and ionic concentrations in the aqueous medium, therefore EIS method provides a capability for characterising the particles in suspensions. Electrical impedance tomography based on EIS measurement or namely, electrical impedance tomography spectroscopy (EITS) could image the spatial distribution of particle characteristics. In this paper, a new method, including test set-up and data analysis, for characterisation of particles in suspensions are developed through the experimental approach. The experimental results on tomographic imaging of colloidal particles

  9. Influence of impedance phase angle on sound pressures and reverberation times in a rectangular room

    DEFF Research Database (Denmark)

    Jeong, Cheol-Ho; Lee, Doheon; Santurette, Sébastien

    2014-01-01

    , but with an absorptive ceiling are investigated. The zero phase angle, which has commonly been assumed in practice, is regarded as reference and differences in the sound pressure level and early decay time from the reference are quantified. As expected, larger differences in the room acoustic parameters are found...... beam tracing model, after verifying it numerically against boundary element simulations. First, the absorption characteristic of the boundary surfaces varies uniformly from 0.2 to 0.8, but with various impedance phase angles. Second, typical non-uniform cases having hard walls and floor...... for larger impedance phase angles. Additionally, binaural impulse responses are compared in a listening test for the uniform absorption cases, revealing that non-zero impedance phase angle cases can be perceptually different from the reference condition in terms of reverberance perception. For the non...

  10. Change in fat-free mass assessed by bioelectrical impedance, total body potassium and dual energy X-ray absorptiometry during prolonged weight loss

    DEFF Research Database (Denmark)

    Hendel, H W; Gotfredsen, A; Højgaard, L

    1996-01-01

    A total of 16 obese women (body mass index (BMI) 30-43 kg m(-2)) participated in a weight reduction study. Before and after a weight loss of 11.7 +/- 7.4 kg (mean +/- SD), body composition was assessed by dual energy X-ray absorptiometry (DXA), and total body potassium counting (TBK). These measu......A total of 16 obese women (body mass index (BMI) 30-43 kg m(-2)) participated in a weight reduction study. Before and after a weight loss of 11.7 +/- 7.4 kg (mean +/- SD), body composition was assessed by dual energy X-ray absorptiometry (DXA), and total body potassium counting (TBK......). These measurements were compared with bioimpedance analysis (BIA) by applying 11 predictive BIA equations published in the literature. Predictive equations for the present study population were developed, with the use of fat-free mass (FFM) as assessed by TBK and DXA as references in multiple regression analysis....... The results of the BIA equations varied widely; FFM was generally overestimated by BIA as compared with DXA and TBK before and after weight loss. During weight loss, the FFM did not change, as estimated by DXA (1.3 +/- 2.3 kg, p > 0.05) and TBK (0.9 +/- 2.9 kg, p > 0.05). The recorded change in impedance (R...

  11. Change in fat-free mass assessed by bioelectrical impedance, total body potassium and dual energy X-ray absorptiometry during prolonged weight loss

    DEFF Research Database (Denmark)

    Hendel, H W; Gotfredsen, A; Højgaard, L

    1996-01-01

    A total of 16 obese women (body mass index (BMI) 30-43 kg m(-2)) participated in a weight reduction study. Before and after a weight loss of 11.7 +/- 7.4 kg (mean +/- SD), body composition was assessed by dual energy X-ray absorptiometry (DXA), and total body potassium counting (TBK). These measu......A total of 16 obese women (body mass index (BMI) 30-43 kg m(-2)) participated in a weight reduction study. Before and after a weight loss of 11.7 +/- 7.4 kg (mean +/- SD), body composition was assessed by dual energy X-ray absorptiometry (DXA), and total body potassium counting (TBK....... The results of the BIA equations varied widely; FFM was generally overestimated by BIA as compared with DXA and TBK before and after weight loss. During weight loss, the FFM did not change, as estimated by DXA (1.3 +/- 2.3 kg, p > 0.05) and TBK (0.9 +/- 2.9 kg, p > 0.05). The recorded change in impedance (R......) was also insignificant. Three BIA equations from the literature, which were not specific for the degree of obesity in the present study group, predicted changes in FFM (from 0.5 + 3.6 to 2.4 +/- 4.4kg, p > 0.05) that were comparable with those estimated by the reference methods. Eight equations from...

  12. Comparison of multi- and single-frequency bioelectrical impedance analysis with dual-energy X-ray absorptiometry for assessment of body composition in post-menopausal women: effects of body mass index and accelerometer-determined physical activity.

    Science.gov (United States)

    Gába, A; Kapuš, O; Cuberek, R; Botek, M

    2015-08-01

    Bioelectric impedance analysis (BIA) is commonly used in research to assess body composition. However, studies that validate the accuracy of BIA exclusively in post-menopausal women are lacking. The main purpose of the present study was to evaluate the agreement of multi-frequency (MF)-BIA and single-frequency (SF)-BIA with dual-energy X-ray absorptiometry (DXA) in the estimation of fat mass (FM) and fat-free mass (FFM) among post-menopausal women with variation in body mass index (BMI) and physical activity (PA). FM and FFM were estimated by BIA and DXA in 146 post-menopausal women with a mean (SD) age of 62.8 (5.2) years. PA was determined by an accelerometer. The mean (SD) difference between MF-BIA and DXA was -1.8 (1.8) kg (P = 0.08) and 1.3 (1.8) kg (P = 0.01) for FM and FFM, respectively. SF-BIA provided a significantly lower estimate of FM [-2.0 (2.2) kg; P = 0.04] and a higher estimate of FFM [1.8 (2.4) kg; P obese and insufficiently active subjects. In other BMI and PA groups, both BIA devices showed a similar deviation from DXA. BIA tends to underestimate FM and overestimate FFM relative to DXA. MF-BIA appears to be a more appropriate method for the assessment of body composition than SF-BIA in post-menopausal woman with BMI >30 kg/m(2) and in those who are insufficiently active. © 2014 The British Dietetic Association Ltd.

  13. [Comparison of consistency in measurement of body fat percentage by dual-energy X-ray absorptiometry and multi-frequency bioelectrical impedance analysis in overweight and obese adults in China].

    Science.gov (United States)

    Wang, Zhenghe; Fu, Lianguo; Yang, Yide; Wang, Shuo; Ma, Jun

    2015-07-01

    To compare the consistency in the measurement of percentage of body fat (PBF) by multi-frequency bioelectrical impedance analysis (MF-BIA) and dual energy X-ray absorptiometry (DXA) in overweight and obese adults in China, and provide evidence for the accurate MF-BIA application in China. A total of 1 323 overweight/obese adults aged 22-55 years were recruited in this study. All the subjects received PBF measurement by both MF-BIA and DXA. The consistency in PBF measurement by MF-BIA and DXA was evaluated by using interclass correlation coefficients (ICC), then the correction prediction models was established. The differences in PBF measurement in male subjects and female subjects between MF-BIA and DXA were statistical significant (all P obese males, -2.5% for overweight females and 0.5% for obese females, respectively. The difference in ICC of PBF between MF-BIA and DXA measurement were statistically significant in all subgroups (P obese males, 0.628 for overweight females and 0.674 for obese females, respectively. The correction prediction models included: PBF (DXA) = 13.425 + 0.719 × PBF (MF-BIA) for overweight males; PBF (DXA) = 12.572 + 0.741 × PBF (MF-BIA) for obese males; PBF (DXA) = 9.785 + 0.802 × PBF (MF-BIA) for overweight females; PBF (DXA) = 20.348 + 0.532 × PBF (MF-BIA) for obese females. The consistency in PBF measurement in overweight/obese adults by MF-BIA and DXA was poor in China. Correction should be conducted when MF-BIA is used in the measurement of PBF.

  14. A comparison of dual energy x-ray absorptiometry and two bioelectrical impedance analyzers to measure body fat percentage and fat-free mass index in a group of Mexican young women.

    Science.gov (United States)

    Velazquez-Alva, Maria Del Consuelo; Irigoyen-Camacho, Maria Esther; Huerta-Huerta, Raquel; Delgadillo-Velazquez, Jaime

    2014-05-01

    Studies of obesity require the estimation of fat mass (FM) and fat-free mass (FFM); therefore it is important to validate methods that evaluate these measurements. We sought to compare two different bioelectrical impedance analysis systems (BIAs) to estimate FM and FFM using dual-energy X-ray absorptiometry (DXA) as reference. We used a cross-sectional design. We evaluated FM and FFM using DXA and two types of BIA equipment: a foot-foot system (FFS) and a hand-foot system (HFS). We conducted paired analysis (paired ttest). We used Bland-Altman plots to assess the relationships between FM and FFMI, limits of agreement were constructed (CL). A total of 175 female students (22.9 ± 2.2 years old) participated in the study. The paired analysis showed significant differences between the mean value of body fat percentage (BF%) estimated by BIA equipment compared to DXA (FFS = 28.7%, HFS= 34.4% and DXA= 35.3%). The mean difference between the HFS and DXA of BF% was -0.96, ((CL -5.29, 7.20). For the FFS, the mean difference was -6.69, (CL -0.29, -13.09). The paired analysis revealed significant differences between the estimates of FFMI by BIA compared to DXA (FFS =16.29, HFS =14.95, DXA =14.18). The mean difference between HFS and DXA was 0.78, and (CL -2.27, 0.72) whereas the FFS mean difference was -2.11 (CL -3.73 -0.49). A different magnitude of bias was observed between the BIA equipment arrays. The HFS appears to be more reliable than the FFS used, particularly in obtaining FFMI in young women. Copyright AULA MEDICA EDICIONES 2014. Published by AULA MEDICA. All rights reserved.

  15. The utility of dual bioelectrical impedance analysis in detecting intra-abdominal fat area in obese patients during weight reduction therapy in comparison with waist circumference and abdominal CT.

    Science.gov (United States)

    Yamakage, Hajime; Ito, Ryo; Tochiya, Mayu; Muranaka, Kazuya; Tanaka, Masashi; Matsuo, Yoshiyuki; Odori, Shinji; Kono, Shigeo; Shimatsu, Akira; Satoh-Asahara, Noriko

    2014-01-01

    An increase in intra-abdominal fat area (IAFA) is an essential component of metabolic syndrome (MetS). Waist circumference (WC) is not a precise measure of IAFA, and computed tomography (CT) is unsuitable for frequent monitoring. Here, we examined utility of a dual bioelectrical impedance analysis (Dual BIA) for measuring IAFA in obese patients during weight reduction. Fat distribution was measured by Dual BIA and CT in 100 obese outpatients. All fat areas including total, IAFA, and subcutaneous fat by Dual BIA were more closely correlated with those by CT than WC. Estimated IAFA by Dual BIA was significantly correlated with number of MetS components as well as CT, but WC was not. Furthermore, in 61 obese patients who received 6-month weight reduction therapy, estimated IAFA by Dual BIA showed an earlier and greater decrease as well as that by CT than WC and BMI. In addition, decrease in estimated IAFA by Dual BIA through weight reduction had a higher correlation with decrease in IAFA by CT, than WC. This study is the first to demonstrate that the change in estimated IAFA by Dual BIA was highly correlated with that in IAFA by CT during weight reduction therapy. Our findings also indicate that estimated IAFA by Dual BIA is, potentially, a better indicator of severity of MetS, cardiovascular risk factors, and effectiveness of weight reduction than WC, and equal to IAFA by CT. Estimated IAFA by Dual BIA may be useful for monitoring the effectiveness of weight reduction therapy in obese patients.

  16. Cross-calibration of multi-frequency bioelectrical impedance analysis with eight-point tactile electrodes and dual-energy X-ray absorptiometry for assessment of body composition in healthy children aged 6-18 years.

    Science.gov (United States)

    Lim, Jung S; Hwang, Jin S; Lee, Jun A; Kim, Dong H; Park, Kyung D; Jeong, Jin S; Cheon, Gi J

    2009-04-01

    In diagnosis and treatment of obesity, body composition analysis including percent body fat (%BF) is useful in the clinical setting. Because bioelectrical impedance analysis (BIA) could be used quickly, easily and was non-invasive in clinical setting, the purpose of the present study was to evaluate the usefulness of multi-frequency BIA with eight-point tactile electrodes (MF-BIA8; InBody 720, Biospace) compared with dual-energy X-ray absorptiometry (DXA) in healthy children and adolescents. A total of 166 children and adolescents under 18 (male, n = 86; female, n = 80) were recruited. Height, weight, body mass index (BMI) and Tanner stage were measured for each subject. The body composition such as fat-free mass (FFM), fat mass (FM), and %BF was measured on BIA and DXA and compared. On linear regression analysis, DXA FFM = 1.006(BIA FFM) + 0.554, R(2) = 0.99 and the standard error of the estimate (SEE) was 1.16 kg; DXA FM = 0.971(BIA FM) - 0.596, R(2) = 0.93; SEE, 1.34 kg; and DXA %BF = 0.940(BIA %BF) - 1.026, R(2) = 0.858; SEE, 3.03%. Limit of agreement in FFM, FM, and %BF was 0.7 +/- 2.3 kg, -0.9 +/- 2.9 kg and -2.2 +/- 6.1%, respectively. Although the %BF was not interchangeable with DXA, MF-BIA8 (InBody 720; Biospace) could be used to measure body composition of children and adolescents in the clinical field because of its high precision.

  17. The Association of Hydration Status with Physical Signs, Symptoms and Survival in Advanced Cancer—The Use of Bioelectrical Impedance Vector Analysis (BIVA) Technology to Evaluate Fluid Volume in Palliative Care: An Observational Study

    Science.gov (United States)

    Mayland, Catriona R.; Mason, Stephen; Cox, Trevor F.; Varro, Andrea; Ellershaw, John

    2016-01-01

    Background Hydration in advanced cancer is a controversial area; however, current hydration assessments methods are poorly developed. Bioelectrical impedance vector analysis (BIVA) is an accurate hydration tool; however its application in advanced cancer has not been explored. This study used BIVA to evaluate hydration status in advanced cancer to examine the association of fluid status with symptoms, physical signs, renal biochemical measures and survival. Materials and methods An observational study of 90 adults with advanced cancer receiving care in a UK specialist palliative care inpatient unit was conducted. Hydration status was assessed using BIVA in addition to assessments of symptoms, physical signs, performance status, renal biochemical measures, oral fluid intake and medications. The association of clinical variables with hydration was evaluated using regression analysis. A survival analysis was conducted to examine the influence of hydration status and renal failure. Results The hydration status of participants was normal in 43 (47.8%), 'more hydrated' in 37 (41.1%) and 'less hydrated' in 10 (11.1%). Lower hydration was associated with increased symptom intensity (Beta = -0.29, p = 0.04) and higher scores for physical signs associated with dehydration (Beta = 10.94, p = 0.02). Higher hydration was associated with oedema (Beta = 2.55, phydrated' patients (44 vs. 68 days; p = 0.049) and in pre-renal failure (44 vs. 100 days; p = 0.003). Conclusions In advanced cancer, hydration status was associated with clinical signs and symptoms. Hydration status and pre-renal failure were independent predictors of survival. Further studies can establish the utility of BIVA as a standardised hydration assessment tool and explore its potential research application, in order to inform the clinical management of fluid balance in patients with advanced cancer. PMID:27673684

  18. Are ethnic and gender specific equations needed to derive fat free mass from bioelectrical impedance in children of South asian, black african-Caribbean and white European origin? Results of the assessment of body composition in children study.

    Directory of Open Access Journals (Sweden)

    Claire M Nightingale

    Full Text Available BACKGROUND: Bioelectrical impedance analysis (BIA is a potentially valuable method for assessing lean mass and body fat levels in children from different ethnic groups. We examined the need for ethnic- and gender-specific equations for estimating fat free mass (FFM from BIA in children from different ethnic groups and examined their effects on the assessment of ethnic differences in body fat. METHODS: Cross-sectional study of children aged 8-10 years in London Primary schools including 325 South Asians, 250 black African-Caribbeans and 289 white Europeans with measurements of height, weight and arm-leg impedance (Z; Bodystat 1500. Total body water was estimated from deuterium dilution and converted to FFM. Multilevel models were used to derive three types of equation {A: FFM = linear combination(height+weight+Z; B: FFM = linear combination(height(2/Z; C: FFM = linear combination(height(2/Z+weight}. RESULTS: Ethnicity and gender were important predictors of FFM and improved model fit in all equations. The models of best fit were ethnicity and gender specific versions of equation A, followed by equation C; these provided accurate assessments of ethnic differences in FFM and FM. In contrast, the use of generic equations led to underestimation of both the negative South Asian-white European FFM difference and the positive black African-Caribbean-white European FFM difference (by 0.53 kg and by 0.73 kg respectively for equation A. The use of generic equations underestimated the positive South Asian-white European difference in fat mass (FM and overestimated the positive black African-Caribbean-white European difference in FM (by 4.7% and 10.1% respectively for equation A. Consistent results were observed when the equations were applied to a large external data set. CONCLUSIONS: Ethnic- and gender-specific equations for predicting FFM from BIA provide better estimates of ethnic differences in FFM and FM in children, while generic equations

  19. Are Ethnic and Gender Specific Equations Needed to Derive Fat Free Mass from Bioelectrical Impedance in Children of South Asian, Black African-Caribbean and White European Origin? Results of the Assessment of Body Composition in Children Study

    Science.gov (United States)

    Nightingale, Claire M.; Rudnicka, Alicja R.; Owen, Christopher G.; Donin, Angela S.; Newton, Sian L.; Furness, Cheryl A.; Howard, Emma L.; Gillings, Rachel D.; Wells, Jonathan C. K.; Cook, Derek G.; Whincup, Peter H.

    2013-01-01

    Background Bioelectrical impedance analysis (BIA) is a potentially valuable method for assessing lean mass and body fat levels in children from different ethnic groups. We examined the need for ethnic- and gender-specific equations for estimating fat free mass (FFM) from BIA in children from different ethnic groups and examined their effects on the assessment of ethnic differences in body fat. Methods Cross-sectional study of children aged 8–10 years in London Primary schools including 325 South Asians, 250 black African-Caribbeans and 289 white Europeans with measurements of height, weight and arm-leg impedance (Z; Bodystat 1500). Total body water was estimated from deuterium dilution and converted to FFM. Multilevel models were used to derive three types of equation {A: FFM = linear combination(height+weight+Z); B: FFM = linear combination(height2/Z); C: FFM = linear combination(height2/Z+weight)}. Results Ethnicity and gender were important predictors of FFM and improved model fit in all equations. The models of best fit were ethnicity and gender specific versions of equation A, followed by equation C; these provided accurate assessments of ethnic differences in FFM and FM. In contrast, the use of generic equations led to underestimation of both the negative South Asian-white European FFM difference and the positive black African-Caribbean-white European FFM difference (by 0.53 kg and by 0.73 kg respectively for equation A). The use of generic equations underestimated the positive South Asian-white European difference in fat mass (FM) and overestimated the positive black African-Caribbean-white European difference in FM (by 4.7% and 10.1% respectively for equation A). Consistent results were observed when the equations were applied to a large external data set. Conclusions Ethnic- and gender-specific equations for predicting FFM from BIA provide better estimates of ethnic differences in FFM and FM in children, while generic equations can

  20. Absorption and impedance boundary conditions for phased geometrical-acoustics methods

    DEFF Research Database (Denmark)

    Jeong, Cheol-Ho

    2012-01-01

    Defining accurate acoustical boundary conditions is of crucial importance for room acoustic simulations. In predicting sound fields using phased geometrical acoustics methods, both absorption coefficients and surface impedances of the boundary surfaces can be used, but no guideline has been...... developed on which boundary condition produces accurate results. In this study, various boundary conditions in terms of normal, random, and field incidence absorption coefficients and normal incidence surface impedance are used in a phased beam tracing model, and the simulated results are validated...... with boundary element solutions. Two rectangular rooms with uniform and non-uniform absorption distributions are tested. Effects of the neglect of reflection phase shift are also investigated. It is concluded that the impedance, random incidence, and field incidence absorption boundary conditions produce...

  1. Utilização da impedância bioelétrica na indicação do excesso de gordura visceral e subcutânea The use of bioelectrical impedance to detect excess visceral and subcutaneous fat

    Directory of Open Access Journals (Sweden)

    Rômulo A. Fernandes

    2007-12-01

    Full Text Available OBJETIVO: Analisar a relação e o desempenho da impedância bioelétrica na indicação do excesso de gordura visceral e sobrepeso/obesidade em jovens brasileiros. MÉTODOS: A amostra foi composta por 811 jovens de ambos os sexos (de 11 a 17 anos. A identificação do estado nutricional foi baseada no valor da dobra cutânea tricipital e gordura relativa (impedância bioelétrica e no excesso de gordura visceral no valor da circunferência de cintura. A análise estatística utilizou valores médios, desvios padrão, correlação linear, teste t de Student e curva ROC. RESULTADOS: Em ambos os gêneros, impedância bioelétrica apresentou bom desempenho na identificação do simultâneo excesso de gordura visceral e sobrepeso/obesidade, sendo mais específica (masculino = 92,4%; feminino = 93,8% do que sensível (masculino = 86,1%; feminino = 71,8%. CONCLUSÃO: Em conclusão, os achados oferecem suporte para o uso da impedância bioelétrica na identificação do excesso de gordura visceral e subcutânea em adolescentes.OBJECTIVE: To analyze bioelectrical impedance performance in detecting the presence of excess visceral fat and overweight/obesity in young Brazilians and how its values are related with them. METHODS: Study sample consisted of 811 adolescents of both genders (11 to 17 years of age. Nutritional status was determined based on triceps skinfold thickness (TSF, relative body fat (bioelectrical impedance, and excess visceral fat as determined by waist circumference. Statistical analysis was performed using means, standard deviations, linear correlation, Student's t test, and ROC curve. RESULTS: Bioelectrical impedance achieved good performance in identifying excess visceral fat associated with overweight/obesity in both genders, and was found to be more specific (male 92.4% and female 93.8% than sensitive (male 86.1% and female 71.8%. CONCLUSION: Our findings support the use of bioelectrical impedance to identify the presence of excess

  2. Couplings in Phase Domain Impedance Modelling of Grid-Connected Converters

    DEFF Research Database (Denmark)

    Dowlatabadi, Mohammadkazem Bakhshizadeh; Wang, Xiongfei; Blaabjerg, Frede

    2016-01-01

    The output impedance of a power converter plays an important role in the stability assessment of the converter. The impedance can be expressed in different frames such as the stationary frame (phase domain) or in the synchronous frame (dq domain). To treat the three-phase system like a single......-phase system, the system can be divided into positive and negative sequences in the phase domain. This paper demonstrates that there exist couplings between the positive and negative sequences, even in a balanced system due to the PLL, which is important for synchronization. Further it will be shown that even...... though these couplings are very small in magnitude, they are important in the stability of the converter....

  3. Development and validation of bioelectrical impedance analysis equations for prediction total body water and fat-free mass using D2O technique in Moroccan children aged between 8 and 11 years old.

    Science.gov (United States)

    El Harchaoui, Imane; El Hamdouchi, Asmaa; Baddou, Issad; El Menchawy, Imane; Benjeddou, Kaoutar; Saeid, Naima; Belghiti, Hakim; El Mzibri, Mohammed; El Kari, Khalid; Aguenaou, Hassan

    2018-02-01

    Estimating body composition using bioelectric impedance analysis (BIA) requires specific prediction equations. The purpose of our study was to examine the validity of published BIA equations for assessing total body water (TBW) and fat-free mass (FFM) using deuterium oxide dilution (D 2 O) as a reference method and to develop new FFM and TBW BIA equations if needed for Moroccan pre-pubertal children. Data were collected from 247 schoolchildren aged 8-11 years old. Children were sorted by gender and age group and assigned in development and validation groups. D 2 O dilution was used as reference method for estimating TBW and FFM. Bland and Altman test, effect size, pure error, and proportional bias were used to assess the reliability of previous published equations. Cross-validation was performed by Bland and Altman test and BIA new equations were developed by linear regression. Previously published equations were tested and showed significant bias values indicating that if used they would provide biased values of TBW and FFM. The new prediction equations developed were: [Formula: see text] (l) = 0.269 + 0.292 Ht 2 /R (cm 2 /Ω) + 0.221 weight (kg) + 0.824 sex (boys = 1, girls = 0) + 0.291 age (years) (R 2  = 0.91, RMSE = 1.54 kg); [Formula: see text] (kg) = -0.450 + 0.380 Ht 2 /R (cm 2 /Ω) + 0.291 weight (kg) + 1.294 sex (boys = 1, girls = 0) + 0.446 age (years) (R 2  = 0.91, RMSE = 1.97 kg). These equations provide better values of proportional bias, agreement, and pure error than the other tested equations. The new BIA prediction equations seem to be the most accurate for Moroccan pre-pubertal children.

  4. Agreement of bioelectrical impedance with dual-energy X-ray absorptiometry and MRI to estimate changes in body fat, skeletal muscle and visceral fat during a 12-month weight loss intervention.

    Science.gov (United States)

    Pietiläinen, Kirsi H; Kaye, Sanna; Karmi, Anna; Suojanen, Laura; Rissanen, Aila; Virtanen, Kirsi A

    2013-05-28

    The aim of the present study was to analyse the agreement of bioelectrical impedance analysis (BIA) compared with dual-energy X-ray absorptiometry (DXA) and MRI in estimating body fat, skeletal muscle and visceral fat during a 12-month weight loss intervention. A total of nineteen obese adults (twelve females, seven males) aged 20·2-48·6 years, mean BMI 34·6 (SE 0·6) kg/m², participated in the study. Body fat, skeletal muscle and visceral fat index were measured by BIA (Omron BF-500; Omron Medizintechnik) and compared with DXA (body fat and skeletal muscle) at baseline, 5 and 12 months, and with MRI (visceral fat) at baseline and 5 months. The subjects lost 8·9 (SE 1·8) kg (9·0 (SE 1·7) %) of body weight during the 12-month intervention. BIA, as compared to DXA, accurately assessed loss of fat (7·0 (SE 1·5) v. 7·0 (SE 1·4) kg, P= 0·94) and muscle (1·0 (SE 0·2) v. 1·4 (SE 0·3) kg, P= 0·18). While body fat was similar by the two methods, skeletal muscle was underestimated by 1-2 kg using BIA at each time point. Compared to MRI, BIA overestimated visceral fat, especially in males. BIA and DXA showed high correlations for kg fat, both cross-sectionally and longitudinally (r 0·91-0·99). BIA, compared with DXA and MRI, detected kg muscle and visceral fat more accurately cross-sectionally (r 0·77-0·87 and r 0·40-0·78, respectively) than their changes longitudinally (r 0·24-0·61 and r 0·46, respectively). BIA is at its best when assessing the amount or changes in fat mass. It is a useful method for measuring skeletal muscle, but limited in its ability to measure visceral fat.

  5. Analysis of Magnetically-Coupled Impedance Source Three-Phase Four-Switch Inverters

    DEFF Research Database (Denmark)

    Li, Kerui; Abdelhakim, Ahmed; Yang, Yongheng

    2017-01-01

    In this paper, magnetically-coupled impedance source (MCIS) three-phase four-switch inverters are introduced for renewable energy applications. This inverter utilizes two single-phase MCIS inverters to obtain a three-phase output, where less component-count is achieved in order to reduce...... the inverter volume. On the other hand, as a result of the reduced number of switches, the proposed inverter suffers from higher voltage stresses. The MCIS inverters are first reviewed. Then, the modulation and operation principle of the MCIS three-phase inverter topology are introduced before sizing...

  6. Positive phase error from parallel conductance in tetrapolar bio-impedance measurements and its compensation

    Directory of Open Access Journals (Sweden)

    Ivan M Roitt

    2010-01-01

    Full Text Available Bioimpedance measurements are of great use and can provide considerable insight into biological processes.  However, there are a number of possible sources of measurement error that must be considered.  The most dominant source of error is found in bipolar measurements where electrode polarisation effects are superimposed on the true impedance of the sample.  Even with the tetrapolar approach that is commonly used to circumvent this issue, other errors can persist. Here we characterise the positive phase and rise in impedance magnitude with frequency that can result from the presence of any parallel conductive pathways in the measurement set-up.  It is shown that fitting experimental data to an equivalent electrical circuit model allows for accurate determination of the true sample impedance as validated through finite element modelling (FEM of the measurement chamber.  Finally, the model is used to extract dispersion information from cell cultures to characterise their growth.

  7. Measurement of void fraction distribution in two-phase flow by impedance CT with neural network

    International Nuclear Information System (INIS)

    Hayashi, Hideaki; Sumida, Isao; Sakai, Sinji; Wakai, Kazunori

    1996-01-01

    This paper describes a new method for measurement of void distribution using impedance CT with a hierarchical neural network. The present method consists of four processes. First, output electric currents are calculated by simulation of various distributions of void fraction. The relationship between distribution of void fraction and electric current is called 'teaching data'. Second, the neural network learns the teaching data by the back propagation method. Third, output electric currents are measured about actual two-phase flow. Finally, distribution of void fraction is calculated by the taught neural network using the measured electric currents. In this paper, measurement and learning parameters are adjusted, experimental results obtained using the impedance CT method are compared with data obtained by the impedance probe method. The results show that our method is effective for measurement of void fraction distribution. (author)

  8. Relationship between Bioelectrical Impedance Analysis and Body ...

    African Journals Online (AJOL)

    Methods: Adolescent pupils aged 10years to 18years from randomly selected secondary schools in Lagos, Nigeria were studied. Body mass index was calculated while percentage body fat was measured using Tanita body® fat scale model BF 681. Overweight and obesity were defined using age and sex specific criteria ...

  9. Skin Blood Flow and Bioelectrical Impedance

    Science.gov (United States)

    1994-06-14

    225-230. Rosdn L, Ostergren J, Fagrell B, Stranden E (1988) Skin micro vascular circulation in the sympathetic dystrophies evaluated by...is lowered, local SBF is reduced by a reflex vasoconstriction brought about by increased venous pressure in the extremity. The transient reductions in...SBF seen in the 35°C test may be due to this reflex vasoconstriction. If so, our study indicates that these reflexes occur not only locally, but also

  10. Is 2D impedance tomography a reliable technique for two-phase flow?

    International Nuclear Information System (INIS)

    Lemonnier, H.; Peytraud, J.F.

    1998-01-01

    Impedance tomography consists in reconstructing the conductivity distribution from electrical data which characterize the electrical response of a medium to arbitrary excitations. Impedance tomography is an ill-conditioned problem and designing a tomograph therefore requires the quantitative knowledge of the sensitivity of the reconstruction to the measurements noise. The numerical conditioning of an original and accurate algorithm has been studied. This algorithm does not suffer from the shortcomings already identified in the literature. It is shown that for media encompassing inclusions which is a typical situation in two-phase flows, the necessary accuracy for the measurements if far beyond any technological reach. Moreover, within these high requirements for accuracy, some side effects must be carefully controlled or compensated and relevant procedures arc provided. Furthermore. reconstruction artifacts are shown and they are found to derive from the unavoidable tridimensional nature of the electric field. For all these reasons, it is concluded that impedance tomography has very low potentialities as an accurate phase fraction distribution measuring technique in any arbitrary two-phase flows. (author)

  11. Estimativa da gordura corporal através de equipamentos de bioimpedância, dobras cutâneas e pesagem hidrostática Comparison of body fat estimation by bioelectric impedance, skinfold thickness, and underwater weighing

    Directory of Open Access Journals (Sweden)

    Maurício Nunes Rodrigues

    2001-08-01

    Full Text Available A estimativa do percentual de gordura (%G pela bioimpedância (BIA tem como vantagem a simplicidade da medida. Contudo, a confiabilidade da BIA tem sofrido críticas. O objetivo deste estudo foi comparar a estimativa do %G através das técnicas de bioimpedância (RJL-101; Byodinamics A-310, Maltron BF-900 e BF-906, de dobras cutâneas (DC e da pesagem hidrostática (PH. Observaram-se 25 indivíduos, homogeneizados segundo raça (branca, gênero (masculino e idade (18 a 36 anos. Para a medida de BIA foi utilizada a padronização proposta por Lukaski et al. (1985, 1986. Para as DC foram utilizadas as equações de å 3 DC e å 7 DC (Jackson, Pollock, 1978. Os valores de %G e de volume residual para PH foram preditos, respectivamente, pelas equações de Siri (1961 e Goldman e Becklake (1959. A análise estatística compreendeu: a comparação entre os métodos através da ANOVA com medidas repetidas seguida de testes post-hoc de Tukey; b correlação de Pearson (r; e c cálculo do erro padrão de estimativa (SEE das técnicas em relação à PH. Os resultados indicaram que: a as medidas de BIA não diferiram significativamente, entre si, para o %G estimado; b As medidas dos aparelhos A-310 e BF-906 não coincidiram com a PH (p The main advantage of the bioelectric impedance method (BIA in the determination of body fat (%BF is the simplicity of the procedure. However, its accuracy and reliability have been criticized. The purpose of this study was to compare the %BF obtained by BIA (RJL-101; Biodynamics A-310, Maltron BF-900 e BF-906, by skinfold thickness (ST, and by underwater weighing (UW. Twenty-five subjects, divided in homogenous groups according to age (18 to 36 years, sex (men, and race (white participated in the study. BIA measures were taken using the Lukaski et al. standardization (1985,1986. ST was taken by using the equation of 3 and 7 skinfolds (Jackson, Pollock, 1978. The values of %BF and residual volume for the UW were estimated

  12. Estimativa da massa muscular esquelética em mulheres idosas: validade da impedância bioelétrica Validity of bioelectrical impedance analysis for the estimation of skeletal muscle mass in elderly women

    Directory of Open Access Journals (Sweden)

    Cassiano Ricardo Rech

    2010-04-01

    Full Text Available O presente estudo tem como objetivos: a verificar a concordância entre os métodos da impedância bioelétrica (BIA e da absortometria radiológica de dupla energia (DXA para a estimativa da massa muscular esquelética (MME; e b analisar o poder preditivo de variáveis antropométricas e da BIA para a predição da MME em idosas. Foram avaliadas 120 mulheres (60 a 81 anos, residentes na região Sul do Brasil. Mensuraram-se as variáveis antropométricas (massa corporal e estatura; a resistência e hidratação dos tecidos livres de gordura foram medidas pela técnica da BIA tetrapolar (Biodinamics - BF-310, e pela DXA de corpo inteiro (Lunar Prodigy DF + 14319 Radiation e software 7.52.002 DPX-L. A diferença entre os métodos foi verificada pelo teste t pareado, análise dos resíduos e o coeficiente de correlação. O valor preditivo das variáveis antropométricas e de BIA foi verificado pela regressão linear múltipla, adotando nível de significância de p 0,01. Observou-se que a BIA subestimou em média 0,8kg (IC95%: -3,7; 2,0kg a MME, quando comparada com a DXA. Foi observada alta correlação entre os métodos (r² = 0,75; p The objectives of the present study were: a to determine the agreement between bioelectrical impedance analysis (BIA and dual-energy X-ray absorptiometry (DXA for the estimation of skeletal muscle mass (SMM, and b to analyze the predictive power of anthropometric variables and BIA for the prediction of SMM in elderly women. A total of 120 women (60 to 81 years, living in the southern region of Brazil, were studied. Anthropometric variables (body weight and height were measured. Resistance and hydration of fat-free tissues were measured by tetrapolar BIA (Biodynamics, BF-310 and by whole-body DXA (Lunar Prodigy DF + 14319 Radiation and DPX-L software, version 7.52.002. Differences between methods were determined using the paired t-test, analysis of residuals and correlation coefficient. The predictive value of the

  13. Measurement of transient two-phase flow velocity using statistical signal analysis of impedance probe signals

    International Nuclear Information System (INIS)

    Leavell, W.H.; Mullens, J.A.

    1981-01-01

    A computational algorithm has been developed to measure transient, phase-interface velocity in two-phase, steam-water systems. The algorithm will be used to measure the transient velocity of steam-water mixture during simulated PWR reflood experiments. By utilizing signals produced by two, spatially separated impedance probes immersed in a two-phase mixture, the algorithm computes the average transit time of mixture fluctuations moving between the two probes. This transit time is computed by first, measuring the phase shift between the two probe signals after transformation to the frequency domain and then computing the phase shift slope by a weighted least-squares fitting technique. Our algorithm, which has been tested with both simulated and real data, is able to accurately track velocity transients as fast as 4 m/s/s

  14. Development of an electrical impedance computed tomographic two-phase flows analyzer. Annual technical report for program renewal

    Energy Technology Data Exchange (ETDEWEB)

    Jones, O.C.

    1993-05-01

    This progress report details the theoretical development, numerical results, experimental design (mechanical), experimental design (electronic), and experimental results for the research program for the development of an electrical impedance computed tomographic two-phase flow analyzer.

  15. Novel Family of Single-Phase Modified Impedance-Source Buck-Boost Multilevel Inverters with Reduced Switch Count

    DEFF Research Database (Denmark)

    Husev, Oleksandr; Strzelecki, Ryszard; Blaabjerg, Frede

    2016-01-01

    This paper describes novel single-phase solutions with increased inverter voltage levels derived by means of a nonstandard inverter configuration and impedance source networks. Operation principles based on special modulation techniques are presented. Detailed component design guidelines along wi...

  16. Studies of phase transition and impedance behavior of Ba(Zr, TiO3 ceramics

    Directory of Open Access Journals (Sweden)

    P. Sateesh

    2015-03-01

    Full Text Available Ceramic samples of Barium Zirconium Titanate (BaZrxTi1-xO3 (BZT were synthesized by conventional solid-state reaction method with different concentrations of x(= 0.05 (BZT1, 0.10 (BZT2, 0.15 (BZT3, 0.20 (BZT4, 0.25 (BZT5, 0.30 (BZT6. Phase confirmation of the samples was done by X-ray diffraction (XRD technique. All the compositions are in cubic structure. XRD pattern was recorded for samples sintered at different sintering temperatures. Lattice parameters increased with addition of Zr+4. Doping with Zr+4 into Barium titanate resulted in interesting changes of electrical properties (dielectric, impedance and ferroelectiricity. The strong influence of Zr doping on the phase transition characteristics of the BZT ceramics was studied from the dielectric response of the samples. Diffusivity of phase transition of the BZT ceramic samples increase with Zr+4 concentration, indicating changes from normal to diffuse transition to relaxor phase transition behavior. Impedance spectroscopy reveals the presence of temperature-dependent grain, grain boundary effects. Polarization–Electricfield (PE loop measurements are also done on the samples.

  17. AC and DC Impedance Extraction for 3-Phase and 9-Phase Diode Rectifiers Utilizing Improved Average Mathematical Models

    Directory of Open Access Journals (Sweden)

    Shahbaz Khan

    2018-03-01

    Full Text Available Switching models possess discontinuous and nonlinear behavior, rendering difficulties in simulations in terms of time consumption and computational complexity, leading to mathematical instability and an increase in its vulnerability to errors. This issue can be countered by averaging detailed models over the entire switching period. An attempt is made for deriving improved dynamic average models of three phase (six-pulse and nine phase (18-pulse diode rectifiers by approximating load current through first order Taylor series. Small signal AC/DC impedances transfer functions of the average models are obtained using a small signal current injection technique in Simulink, while transfer functions are obtained through identification of the frequency response into the second order system. For the switch models in Simulink and the experimental setup, a small signal line to line shunt current injection technique is used and the obtained frequency response is then identified into second order systems. Sufficient matching among these results proves the validity of the modelling procedure. Exact impedances of the integral parts, in interconnected AC/DC/AC systems, are required for determining the stability through input-output impedances.

  18. Impedance void-meter and neural networks for vertical two-phase flows

    International Nuclear Information System (INIS)

    Mi, Y.; Li, M.; Xiao, Z.; Tsoukalas, L.H.; Ishii, M.

    1998-01-01

    Most two-phase flow measurements, including void fraction measurements, depend on correct flow regime identification. There are two steps towards successful identification of flow regimes: one is to develop a non-intrusive instrument to demonstrate area-averaged void fluctuations, the other to develop a non-linear mapping approach to perform objective identification of flow regimes. A non-intrusive impedance void-meter provides input signals to a neural mapping approach used to identify flow regimes. After training, both supervised and self-organizing neural network learning paradigms performed flow regime identification successfully. The methodology presented holds considerable promise for multiphase flow diagnostic and measurement applications. (author)

  19. Adjusting output impedance using a PI controller to improve the stability of a single-phase inverter under weak grid

    Directory of Open Access Journals (Sweden)

    Jiao Jiao

    2016-11-01

    Full Text Available Explored in this paper is the grid impedance effect on the stability of a single-phase grid connected inverter with an LC filter based on an analysis of the inverter output impedance. For a single-phase grid connected inverter, a PI controller is often used to regulate the current injected into the grid. However, the control performance can be influenced when the inverter is connected to a weak grid. Also, the utility grid has background harmonic noise, which can make the injected current distorted. Therefore, analysis of the output impedance of a single-phase grid connected inverter is important for the robustness and stability of the system. By modeling the output impedance of inverter, it can be determined that the proportional gain and integral gain of the controller have an effect on the output impedance. Analytical results show that by adjusting the PI controller parameters, the ability for harmonic reduction and stability of the system can be improved. Simulation and experiments using a 1 kW single-phase grid connected inverter verify the effectiveness of the theoretical analysis.

  20. Battery Internal Temperature Estimation for LiFePO4 Battery Based on Impedance Phase Shift under Operating Conditions

    Directory of Open Access Journals (Sweden)

    Jiangong Zhu

    2017-01-01

    Full Text Available An impedance-based temperature estimation method is investigated considering the electrochemical non-equilibrium with short-term relaxation time for facilitating the vehicular application. Generally, sufficient relaxation time is required for battery electrochemical equilibrium before the impedance measurement. A detailed experiment is performed to investigate the regularity of the battery impedance in short-term relaxation time after switch-off current excitation, which indicates that the impedance can be measured and also has systematical decrement with the relaxation time growth. Based on the discussion of impedance variation in electrochemical perspective, as well as the monotonic relationship between impedance phase shift and battery internal temperature in the electrochemical equilibrium state, an exponential equation that accounts for both measured phase shift and relaxation time is established to correct the measuring deviation caused by electrochemical non-equilibrium. Then, a multivariate linear equation coupled with ambient temperature is derived considering the temperature gradients between the active part and battery surface. Equations stated above are all identified with the embedded thermocouple experimentally. In conclusion, the temperature estimation method can be a valuable alternative for temperature monitoring during cell operating, and serve the functionality as an efficient implementation in battery thermal management system for electric vehicles (EVs and hybrid electric vehicles (HEVs.

  1. LCL filter design for three-phase two-level power factor correction using line impedance stabilization network

    DEFF Research Database (Denmark)

    Kouchaki, Alireza; Nymand, Morten

    2016-01-01

    This paper presents LCL filter design method for three-phase two-level power factor correction (PFC) using line impedance stabilization network (LISN). A straightforward LCL filter design along with variation in grid impedance is not simply achievable and inevitably lead to an iterative solution...... for filter. By introducing of fast power switches for PFC applications such as silicon-carbide, major current harmonics around the switching frequency drops in the region that LISN can actively provide well-defined impedance for measuring the harmonics (i.e. 9 kHz- 30MHz). Therefore, LISN can be replaced...... is derived using the current ripple behavior of converter-side inductor. The grid-side inductor is achieved as a function of LISN impedance to fulfill the grid regulation. To verify the analyses, an LCL filter is designed for a 5 kW SiC-based PFC. The simulation and experimental results support the validity...

  2. Estimativa da composição corporal e análise de concordância entre analisadores de impedância bioelétrica bipolar e tetrapolar Body composition estimation and agreement analysis between bipolar and tetrapolar bioelectrical impedance analyzers

    Directory of Open Access Journals (Sweden)

    José Claudio Jambassi Filho

    2010-02-01

    Full Text Available O objetivo deste estudo foi analisar as estimativas da composição corporal e a concordância das medidas produzidas por meio de dois diferentes analisadores de impedância bioelétrica em homens adultos jovens. Vinte e dois sujeitos (23,6 ± 2,9 anos; 73 ± 6,8kg; 177,6 ± 6,0cm; 23,1 ± 1,9kg/m², aparentemente saudáveis, foram submetidos a medidas de impedância bioelétrica por meio dos analisadores tetrapolar de corpo inteiro (TCI, Biodynamic Body Composition Analyser, modelo 310 e bipolar para membros superiores (BMS, Omron tm, modelo HBF-306BL após jejum de 12h. Estimativas da gordura corporal relativa (%GC, massa livre de gordura (MLG e massa gorda (MG foram estabelecidas a partir das informações fornecidas pelos dois equipamentos. Nenhuma diferença estatisticamente significante foi verificada para %GC (10,9 ± 4,3 vs. 10,0 ± 4,2%; P = 0,09, MG (8,1 ± 3,5 vs. 7,4 ± 3,5kg; P = 0,10 e MLG (64,9 ± 5,2 vs. 65,5 ± 4,9kg; P = 0,09 entre TCI e BMS, respectivamente. Correlações positivas e significantes (P The aim of this study was to analyze the body composition estimation and agreement of the measurements produced from two bioelectrical impedance analysers in young adult men. Twenty-two apparently healthy subjects (23.6 ± 2.9 yrs; 73.0 ± 6.8 kg; 177.6 ± 6.0 cm; 23.1 ± 1.9 kg/m², were submitted to bioelectrical impedance measurements by tetra-polar whole body (TWB, Biodynamic Body Composition Analyser, model 310 and bipolar for upper body (BUB, OMRON TM, model HBF-306BL after 12 h fast. Relative body fat (%BF, lean body mass (LBM and fat mass (FM estimation were established from information supplied by two analysers. No significant difference was verified for %BF (10.9 ±4.3 vs. 10.0 ±4.2%; P = 0.09, FM (8.1 ±3.5 vs. 7.4 ±3.5 kg; P = 0.10 or LBM (64.9 ±5.2 vs. 65.5 ±4.9 kg; P = 0.09 between TWB and BUB, respectively. Positive significant correlations (P < 0.001 were found between both analysers for LBM (r = 0.948, FM (r

  3. Phase boundary estimation in electrical impedance tomography using the Hooke and Jeeves pattern search method

    International Nuclear Information System (INIS)

    Khambampati, Anil Kumar; Kim, Kyung Youn; Ijaz, Umer Zeeshan; Lee, Jeong Seong; Kim, Sin

    2010-01-01

    In industrial processes, monitoring of heterogeneous phases is crucial to the safety and operation of the engineering structures. Particularly, the visualization of voids and air bubbles is advantageous. As a result many studies have appeared in the literature that offer varying degrees of functionality. Electrical impedance tomography (EIT) has already been proved to be a hallmark for process monitoring and offers not only the visualization of the resistivity profile for a given flow mixture but is also used for detection of phase boundaries. Iterative image reconstruction algorithms, such as the modified Newton–Raphson (mNR) method, are commonly used as inverse solvers. However, their utility is problematic in a sense that they require the initial solution in close proximity of the ground truth. Furthermore, they also rely on the gradient information of the objective function to be minimized. Therefore, in this paper, we address all these issues by employing a direct search algorithm, namely the Hooke and Jeeves pattern search method, to estimate the phase boundaries that directly minimizes the cost function and does not require the gradient information. It is assumed that the resistivity profile is known a priori and therefore the unknown information will be the size and location of the object. The boundary coefficients are parameterized using truncated Fourier series and are estimated using the relationship between the measured voltages and injected currents. Through extensive simulation and experimental result and by comparison with mNR, we show that the Hooke and Jeeves pattern search method offers a promising prospect for process monitoring

  4. Impedance self-matching ultra-narrow linewidth fiber resonator by use of a tunable π-phase-shifted FBG.

    Science.gov (United States)

    Jing, Mingyong; Yu, Bo; Hu, Jianyong; Hou, Huifang; Zhang, Guofeng; Xiao, Liantuan; Jia, Suotang

    2017-05-15

    In this paper, we present a novel ultra-narrow linewidth fiber resonator formed by a tunable polarization maintaining (PM) π-phase-shifted fiber Bragg grating and a PM uniform fiber Bragg grating with a certain length of PM single mode fiber patch cable between them. Theoretical prediction shows that this resonator has ultra-narrow linewidth resonant peaks and is easy to realize impedance matching. We experimentally obtain 3 MHz narrow linewidth impedance matched resonant peak in a 7.3 m ultra-long passive fiber cavity. The impedance self-matching characteristic of this resonator also makes itself particularly suitable for use in ultra-sensitive sensors, ultra-narrow band rejection optical filters and fiber lasers applications.

  5. An improved design of virtual output impedance loop for droop-controlled parallel three-phase Voltage Source Inverters

    DEFF Research Database (Denmark)

    Wang, Xiongfei; Blaabjerg, Frede; Chen, Zhe

    2012-01-01

    The virtual output impedance loop is known as an effective way to enhance the load sharing stability and quality of droop-controlled parallel inverters. This paper proposes an improved design of virtual output impedance loop for parallel three-phase voltage source inverters. In the approach......-sequence virtual resistance even in the case of feeding a balanced three-phase load. Furthermore, to adapt to the variety of unbalanced loads, a dynamically-tuned negative-sequence resistance loop is designed, such that a good compromise between the quality of inverter output voltage and the performance of load...... sharing can be obtained. Finally, laboratory test results of two parallel three-phase voltage source inverters are shown to confirm the validity of the proposed method....

  6. Signal-to-Noise Ratio Analysis of a Phase-Sensitive Voltmeter for Electrical Impedance Tomography.

    Science.gov (United States)

    Murphy, Ethan K; Takhti, Mohammad; Skinner, Joseph; Halter, Ryan J; Odame, Kofi

    2017-04-01

    In this paper, thorough analysis along with mathematical derivations of the matched filter for a voltmeter used in electrical impedance tomography systems are presented. The effect of the random noise in the system prior to the matched filter, generated by other components, are considered. Employing the presented equations allow system/circuit designers to find the maximum tolerable noise prior to the matched filter that leads to the target signal-to-noise ratio (SNR) of the voltmeter, without having to over-design internal components. A practical model was developed that should fall within 2 dB and 5 dB of the median SNR measurements of signal amplitude and phase, respectively. In order to validate our claims, simulation and experimental measurements have been performed with an analog-to-digital converter (ADC) followed by a digital matched filter, while the noise of the whole system was modeled as the input referred at the ADC input. The input signal was contaminated by a known value of additive white Gaussian noise (AWGN) noise, and the noise level was swept from 3% to 75% of the least significant bit (LSB) of the ADC. Differences between experimental and both simulated and analytical SNR values were less than 0.59 and 0.35 dB for RMS values ≥ 20% of an LSB and less than 1.45 and 2.58 dB for RMS values circuit designers in EIT, and a more accurate error analysis that was previously missing in EIT literature.

  7. Electrochemical impedance pattern recognition for detection of hidden chemical corrosion on aircraft components, phase 1

    Science.gov (United States)

    Sammells, A. F.; Bowers, J. S.

    1995-02-01

    This investigation addressed the need for diagnostic instrumentation compatible with performing the Nondestructive Evaluation (NDE) of hidden chemical corrosion with a high degree of accuracy, sensitivity and versatility on both titanium and aluminum alloys currently used in Air Force and commercial aircraft. The overall approach was directed towards development of pattern recognition schemes based upon the on-line data acquisition of Fast Fourier Transform Electrochemical Impedance Spectroscopy (FFTEIS) instrumentation from the suspect hidden chemical corrosion site. Resulting impedance patterns were then analyzed by application of a Neural Network pattern recognition scheme. The Neural Network Analysis (NNA) was then trained to both detect and grade the severity of hidden corrosion present on the aircraft metal substrate interface of interest. Nueral Net Analysis of FFTEIS data was verified as a powerful diagnostic strategy for in situ hidden corrosion process identification, quantitative analysis and severity grading. Correlations between impedance measurements and corrosion depth were verified by subsequent SEM and EDX examination of the metal interfacial regions. The approach will also be powerful for gaining fundamental information into the nature of corrosion processes and conditions leading to their inception at hidden sites.

  8. Bioelectrical impedance and visceral fat: a comparison with computed tomography in adults and elderly; Bioimpedancia eletrica e gordura visceral: uma comparacao com a tomografia computadorizada em adultos e idosos

    Energy Technology Data Exchange (ETDEWEB)

    Eickemberg, Michaela [Universidade Federal da Bahia (UFBA), Salvador, BA (Brazil); Roriz, Anna Karla Carneiro [Universidade Federal da Bahia (UFBA), Salvador, BA (Brazil); Fontes, Gardenia Abreu Vieira [Universidade Federal da Bahia (UFBA), Salvador, BA (Brazil); Sampaio, Lilian Ramos [Universidade Federal de Sao Paulo (Unifesp), Sao Paulo, SP (Brazil)

    2013-05-01

    Objective: To evaluate the association between electrical bioimpedance analysis (BIA) and visceral fat (VF) in adult and elderly patients. Subjects and methods: This was a cross-sectional study, with a sample of 191 subjects (52% women, 49% elderly) stratified by sex, age and body mass. Computerized tomography (VF area) and BIA (percentage of total body fat (%TBF-BIA), phase angle, reactance and resistance) data were generated. Statistical analysis was based on Pearson's Correlation Coefficient, Anova, Pearson's Chi-square, and ROC curves. Results: VF areas {>=} 130 cm{sup 2} were more prevalent among the elderly and among men. Adult females showed a stronger correlation between GV and %TBF-BIA. The other groups showed similar results and statistically significant correlations. Correlations between GV and phase angle were weak and not statistically significant. ROC Curves analyzes showed the following %TBF-BIA, which identified excess VF: for male subjects: 21.5% (adults) and 24.25% (elderly); for female subjects: 35.05% (adults) and 38.45% (elderly) with sensitivity of 78.6%, 82.1%, 83.3%, and 66.7%, and specificity of 70.6%, 62.5%, 79.1%, and 69%, respectively. Conclusion: BIA was found to have satisfactory sensitivity and specificity to predict VF; however, other devices and other techniques should be investigated to improve VF prediction. (author)

  9. Predicting the dental implant stability based on the antiresonance phase of a piezo-based impedance sensor

    Directory of Open Access Journals (Sweden)

    Paramita Banerjee

    2017-01-01

    Full Text Available Background: The stability of dental implants (DIs in in vivo tests can be determined using noninvasive resonance frequency analysis technique. A low-cost piezo-based sensor has been developed for this purpose which uses a readily available two-terminal piezo element, to which a metal substrate is adhesively glued for attaching the implant. Aim: The attainment of implant stability in dynamic tests using this sensor must be standardized in terms of the major antiresonance (AR in the impedance phase responses using sensor-DI assembly. This will be used to predetermine the dimensions of the glued metal substrate in the sensor design. Materials and Methods: Multiple sensors with varying sensor dimensions were developed. Static and dynamic impedance studies were performed on these and corresponding sensor-implant assemblies. Static tests as well as in vitro tests with the sensor-implant assembly dipped in a standardized dental plaster mixture were performed in controlled laboratory conditions. Results: The probability of acceptance of the hypothesis has been checked using binomial distribution with a significance level of 5%. Statistically observed that for 95% of the cases where the DI becomes stable in dental plaster, both AR phase and AR frequency (ARF return to their corresponding static values. Furthermore, for a piezo element, whose ARF is within 6–6.6 kHz, the sensor yields maximal phase when the length of the metallic strip is 2 cm. Conclusions: Experimental validation supports both claims. Hence, this work can be extended to in vivo DI stability determination and design aspects of the corresponding sensor.

  10. Cross validation of bioelectrical impedance equations for men

    Directory of Open Access Journals (Sweden)

    Maria Fátima Glaner

    2005-06-01

    Full Text Available The purpose of this study was to analyze the cross validity of bioimpedance equations (BIA on the estimation of the fat free mass (FFM of 44 men, with mean age of 24.98 ± 3.40 years and relative body fat (%BF of 17.15 ± 6.41%. A dual energy x-ray absorptiometry was used as a reference method for %BF and FFM. Total body resistance was assessed by the Biodynamics (Model 310. The equations analyzed in this study were: two equations (Eq.1 and 2 developed by Carvalho e Pires Neto (1998; one equation (Eq. 3 developed by Rising et al.(1991; one equation (Eq. 4 developed by Oppliger et al.(1991; two equations (Eq. 5 (%FM RESUMO Este estudo teve como objetivo analisar a validade concorrente de equações de impedância bioelétrica (IB para estimar a massa corporal livre de gordura (MLG, em 44 homens, com idade média de 24,98 ± 3,40 anos e gordura relativa (%G de 17,15 ± 6,41 %. A absortometria de raio-x de dupla energia foi usada como critério, para mensurar a %G e a MLG, e para obter estas variáveis decorrentes das equações de IB foi utilizado o Biodynamics (Modelo 310. As equações de IB analisadas neste estudo foram: duas equações (Eq. 1 e 2 de Carvalho e Pires Neto (1998; uma equação (Eq. 3 de Rising et al. (1991; uma equação (Eq. 4 de Oppliger et al.(1991; duas equações (Eq. 5 (%G < 20% e Eq. 6 (%G ≥ 20% de Segal et al. (1988. Os critérios adotados para validação foram os propostos por Lohman (1991. Todas as correlações foram altas e significativas, oscilando de 0,906 (Eq. 2 a 0,981 (Eq. 6. As equações 1 a 5 superestimaram de forma significativa (p < 0,001 a MLG, sendo que os erros constantes variaram de 1,32 kg (Eq. 5 a 5,90 kg (Eq. 4. A equação 6 atendeu a todos os critérios de validação, apresentando: correlação = 0,981; erro constante = -0,38 kg; erro total = 1,10 kg. Esta equação de Segal et al.(1988, para homens com gordura relativa ≥ 20% (Eq. 6 foi a única que apresentou validade concorrente, estimando a MLG, com um erro padrão de estimativa 0,90 kg.

  11. Validation of bioelectrical impedance analysis in Ethiopian adults with HIV

    DEFF Research Database (Denmark)

    Hegelund, Maria H; Wells, Jonathan C; Girma, Tsinuel

    2017-01-01

    in populations of different ethnic origin and health status. The aim of the present study was to test the validity of BIA in Ethiopian antiretroviral-naive HIV patients. BIA was validated against the 2H dilution technique by comparing fat-free mass (FFM) measured by the two methods using paired t tests and Bland......-Altman plots. BIA was based on single frequency (50 kHz) whole-body measurements. Data were obtained at three health facilities in Jimma Zone, Oromia Region, South-West Ethiopia. Data from 281 HIV-infected participants were available. Two-thirds were female and the mean age was 32·7 (sd 8·6) years. Also, 46...... % were underweight with a BMI below 18·5 kg/m2. There were no differences in FFM between the methods. Overall, BIA slightly underestimated FFM by 0·1 kg (-0·1, 95 % CI -0·3, 0·2 kg). The Bland-Altman plot indicated acceptable agreement with an upper limit of agreement of 4·5 kg and a lower limit...

  12. Use of electrocardiogram (ECG) electrodes for Bioelectrical Impedance Analysis (BIA)

    Science.gov (United States)

    Caicedo-Eraso, J. C.; González-Correa, C. H.; González-Correa, C. A.

    2012-12-01

    BIA is a safe, noninvasive, portable and relatively inexpensive method of estimating body composition that is practical and suitable for individual use and large-scale studies. However, the cost of the electrodes recommended by some BIA manufacturers is too high for developing countries; where very often the long and complicated process of importation reduces the time they can be used. The purpose of this study was to evaluate the use of two types of ECG electrodes (2290 and 2228 by 3M®) in BIA measurements to decrease the costs of the test. The results showed that the 2228 ECG electrodes can be used in BIA measurements for adult's body composition assessment. These electrodes are available in the domestic market and their costs are 92% lower than the electrodes recommended by manufacturer. The results show a new cost-benefit relation for BIA method and make this a more accessible tool for individual tests, large-scale researches and studies in the community.

  13. Resistivity and phase in localized BIA

    Science.gov (United States)

    Shiffman, C. A.; Aaron, R.; Amoss, V.; Therrien, J.; Coomler, K.

    1999-10-01

    We describe a system for highly reproducible non-invasive rf impedance measurements as a function of position along body segments such as the thigh. Results are reported for mainly healthy male and female subjects ranging in age from 19 to 65 and in body-mass index from 15 to 40. A principal conclusion is that the phase of the impedance falls monotonically with increasing distance from the knee, with average values substantially above what is found using standard, whole-body bioelectrical impedance analysis (BIA). To compensate for thigh shape, the data are further analysed using an anatomical model based on reasonable approximations for the distributions of muscle, fat and bone, yielding values of the effective resistivity for current flow parallel to the muscle fibres. The phase and resistivity results are discussed with reference to the whole-body BIA study of maintenance haemodialysis patients by Chertow et al, and in regard to possible physiological correlations observed in this work.

  14. Impedance Scaling and Impedance Control

    International Nuclear Information System (INIS)

    Chou, W.; Griffin, J.

    1997-06-01

    When a machine becomes really large, such as the Very Large Hadron Collider (VLHC), of which the circumference could reach the order of megameters, beam instability could be an essential bottleneck. This paper studies the scaling of the instability threshold vs. machine size when the coupling impedance scales in a ''normal'' way. It is shown that the beam would be intrinsically unstable for the VLHC. As a possible solution to this problem, it is proposed to introduce local impedance inserts for controlling the machine impedance. In the longitudinal plane, this could be done by using a heavily detuned rf cavity (e.g., a biconical structure), which could provide large imaginary impedance with the right sign (i.e., inductive or capacitive) while keeping the real part small. In the transverse direction, a carefully designed variation of the cross section of a beam pipe could generate negative impedance that would partially compensate the transverse impedance in one plane

  15. Mechanical impedance

    OpenAIRE

    Couroussé, Damien

    2007-01-01

    International audience; Mechanical impedance is a transposition to mechanics of the term impedance that is used and defined in circuit theory. The theory of circuit (theory of Kirchhoff networks) is basically applicable to electric networks but can be considered more generally as a unifying simplified theory of physics available in several domains like mechanics, electromagnetism, aero-acoustics and fluids mechanics.

  16. A parametric framework for modelling of bioelectrical signals

    CERN Document Server

    Mughal, Yar Muhammad

    2016-01-01

    This book examines non-invasive, electrical-based methods for disease diagnosis and assessment of heart function. In particular, a formalized signal model is proposed since this offers several advantages over methods that rely on measured data alone. By using a formalized representation, the parameters of the signal model can be easily manipulated and/or modified, thus providing mechanisms that allow researchers to reproduce and control such signals. In addition, having such a formalized signal model makes it possible to develop computer tools that can be used for manipulating and understanding how signal changes result from various heart conditions, as well as for generating input signals for experimenting with and evaluating the performance of e.g. signal extraction methods. The work focuses on bioelectrical information, particularly electrical bio-impedance (EBI). Once the EBI has been measured, the corresponding signals have to be modelled for analysis. This requires a structured approach in order to move...

  17. Method of recording bioelectrical signals using a capacitive coupling

    Science.gov (United States)

    Simon, V. A.; Gerasimov, V. A.; Kostrin, D. K.; Selivanov, L. M.; Uhov, A. A.

    2017-11-01

    In this article a technique for the bioelectrical signals acquisition by means of the capacitive sensors is described. A feedback loop for the ultra-high impedance biasing of the input instrumentation amplifier, which provides receiving of the electrical cardiac signal (ECS) through a capacitive coupling, is proposed. The mains 50/60 Hz noise is suppressed by a narrow-band stop filter with an independent notch frequency and quality factor tuning. Filter output is attached to a ΣΔ analog-to-digital converter (ADC), which acquires the filtered signal with a 24–bit resolution. Signal processing board is connected through universal serial bus interface to a personal computer, where ECS in a digital form is recorded and processed.

  18. On the impedance and phase transition of thin film all-solid-state batteries based on the Li4Ti5O12 system

    Science.gov (United States)

    Schichtel, Patrick; Geiß, Matthias; Leichtweiß, Thomas; Sann, Joachim; Weber, Dominik A.; Janek, Jürgen

    2017-08-01

    Model-type thin film all-solid-state batteries (ASSB) of the type Li/;LiPON;/Li4Ti5O12 are characterized by impedance spectroscopy as function of the state of charge. Both the contact of Li4Ti5O12 (LTO) to the substrate and current collector as well as the Li ion transport through the LTO thin film prove to be important factors for the rate limitation of the cell. The ionic charge transfer resistance between Li4Ti5O12 and ;LiPON; is proven to not be a rate limiting factor. The impedance measurements are interpreted in terms of the mechanism of phase change in the Li4Ti5O12 thin film and the data indicate a solid solution mechanism of phase change. The resulting data are compared to recent results for the Li/;LiPON;/LiCoO2 system, and several key similarities and differences are highlighted mostly involving the solid electrolyte/Li interface and the degradation thereof. The results are meant to improve the understanding of interfaces in ASSB in general rather than to advance high performance batteries.

  19. Phase transformation and impedance spectroscopic study of Ba substituted Na{sub 0.5}Bi{sub 0.5}TiO{sub 3} ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Kumari, Rekha [Department of Applied Physics, Guru Jambheshwar University of Science & Technology, Hisar, 125001, Haryana (India); Ahlawat, Neetu, E-mail: neetugju@yahoo.co.in [Department of Applied Physics, Guru Jambheshwar University of Science & Technology, Hisar, 125001, Haryana (India); Agarwal, Ashish; Sanghi, Sujata [Department of Applied Physics, Guru Jambheshwar University of Science & Technology, Hisar, 125001, Haryana (India); Sindhu, Monica [Department of Physics, MKJK College, Rohtak, 124001, Haryana (India); Ahlawat, Navneet [Matu Ram Institute of Engineering and Management, Rohtak, 124001, Haryana (India)

    2016-08-15

    (Na{sub 0.5}Bi{sub 0.5}){sub 1−x}Ba{sub x}TiO{sub 3} (x = 0.05, 0.1 and 0.15) ceramics abbreviated as (NBBT1, NBBT2 and NBBT3) are fabricated by conventional ceramic fabrication technique. The analysis of X-ray diffraction pattern of the prepared ceramic performed by Rietveld refinement indicate that crystal structure is rhombohedral for NBBT1, tetragonal for NBBT3 and a phase boundary occurs for NBBT2. Impedance spectroscopy has been employed to study the electrical properties of these ceramics in the frequency range of 10 Hz to 5 MHz and in a temperature range of 303 K–723 K. Frequency and temperature dependent electrical data is analyzed in the framework of conductivity, impedance and electric modulus formalisms. Conductivity spectrum obeys double power law for NBBT1, which is evidenced from two different dispersion regions. While for NBBT2 and NBBT3 only single power law is observed. Relaxation frequency for impedance is found to increase with temperature and obeys Arrhenius relationship with activation energy ≈0.764, 0.527 and 0.471 eV for NBBT1, NBBT2 and NBBT3 respectively. Variation of dielectric constant and tanδ with frequency at different temperatures was analyzed with the help of Maxwell–Wagner and Koop's phenomenogical theory. The presence of peaks in plots showing frequency dependence of tanδ for NBBT2 and NBBT3 indicates relaxor behavior of these compositions. - Highlights: • (Na{sub 0.5}Bi{sub 0.5}){sub 1−x}Ba{sub x}TiO{sub 3} (x = 0.05, 0.1, 0.15) ceramics have been synthesized. • There is change in crystal structure with Ba doping. • NBBT2 and NBBT3 show relaxor behavior.

  20. Avaliação de gordura corporal pela bioimpedância elétrica e sua correlação com diferentes pontos anatômicos de medida da circunferência da cintura em crianças Body fat assessment by bioelectrical impedance and its correlation with different anatomical sites used in the measurement of waist circumference in children

    Directory of Open Access Journals (Sweden)

    Mônica de Souza Lima Sant'Anna

    2009-02-01

    Full Text Available OBJETIVO: Comparar os diferentes pontos anatômicos de medida da circunferência da cintura, bem como a eficácia desses locais em predizer o percentual de gordura corporal mensurado pela bioimpedância elétrica tetrapolar. MÉTODOS: Foram avaliadas 205 crianças de 6 a 9 anos de idade de ambos os sexos. Foram coletados dados de peso, estatura e circunferência da cintura em três locais diferentes: na menor curvatura abdominal, sobre a cicatriz umbilical e no ponto médio entre a última costela e crista ilíaca. A avaliação do estado nutricional foi realizada a partir do índice de massa corporal/idade recomendado pela Organização Mundial de Saúde. RESULTADOS: No presente estudo houve homogeneidade entre os sexos, e a idade média foi de 7,2±1,2 anos. Em relação ao estado nutricional, 6,3% das crianças apresentaram baixo peso, 75,1% eram eutróficas, 7,3% apresentaram sobrepeso e 11,2% obesidade. No sexo masculino não houve diferença estatística entre os diferentes locais de medida. No feminino, a medida sobre a cicatriz umbilical foi estatisticamente maior. Na análise de correlação, a circunferência medida no ponto médio foi a que obteve melhor correlação com o percentual de gordura corporal, com valores de 0,50 nos meninos e 0,62 nas meninas. CONCLUSÃO: A circunferência da cintura medida no ponto médio entre a crista ilíaca e ultima costela foi a que apresentou melhor correlação com o percentual de gordura corporal.OBJECTIVE: To compare the different anatomical sites used in the measurement of waist circumference, as well as the effectiveness of these landmarks to predict the percentage of body fat by tetrapolar bioelectrical impedance analysis. METHODS: We evaluated 205 children from 6 to 9 years of age of both sexes. Data on weight, height and waist circumference were collected at three different sites: at the lower abdominal curvature, above the navel and at the midpoint between the last rib and the iliac crest

  1. Bioelectric Applications for Treatment of Melanoma

    Energy Technology Data Exchange (ETDEWEB)

    Beebe, Stephen J., E-mail: sbeebe@odu.edu; Schoenbach, Karl H.; Heller, Richard [Frank Reidy Research Center for Bioelectrics/Old Dominion University 4211 Monarch Way, Suite 300, Norfolk, Virginia 23508 (United States)

    2010-09-27

    Two new cancer therapies apply bioelectric principles. These methods target tumor structures locally and function by applying millisecond electric fields to deliver plasmid DNA encoding cytokines using electrogene transfer (EGT) or by applying rapid rise-time nanosecond pulsed electric fields (nsPEFs). EGT has been used to locally deliver cytokines such as IL-12 to activate an immune response, resulting in bystander effects. NsPEFs locally induce apoptosis-like effects and affect vascular networks, both promoting tumor demise and restoration of normal vascular homeostasis. EGT with IL-12 is in melanoma clinical trials and nsPEFs are used in models with B16F10 melanoma in vitro and in mice. Applications of bioelectrics, using conventional electroporation and extensions of it, provide effective alternative therapies for melanoma.

  2. Bioelectric Applications for Treatment of Melanoma

    International Nuclear Information System (INIS)

    Beebe, Stephen J.; Schoenbach, Karl H.; Heller, Richard

    2010-01-01

    Two new cancer therapies apply bioelectric principles. These methods target tumor structures locally and function by applying millisecond electric fields to deliver plasmid DNA encoding cytokines using electrogene transfer (EGT) or by applying rapid rise-time nanosecond pulsed electric fields (nsPEFs). EGT has been used to locally deliver cytokines such as IL-12 to activate an immune response, resulting in bystander effects. NsPEFs locally induce apoptosis-like effects and affect vascular networks, both promoting tumor demise and restoration of normal vascular homeostasis. EGT with IL-12 is in melanoma clinical trials and nsPEFs are used in models with B16F10 melanoma in vitro and in mice. Applications of bioelectrics, using conventional electroporation and extensions of it, provide effective alternative therapies for melanoma

  3. Bioelectric Applications for Treatment of Melanoma

    Directory of Open Access Journals (Sweden)

    Richard Heller

    2010-09-01

    Full Text Available Two new cancer therapies apply bioelectric principles. These methods target tumor structures locally and function by applying millisecond electric fields to deliver plasmid DNA encoding cytokines using electrogene transfer (EGT or by applying rapid rise-time nanosecond pulsed electric fields (nsPEFs. EGT has been used to locally deliver cytokines such as IL-12 to activate an immune response, resulting in bystander effects. NsPEFs locally induce apoptosis-like effects and affect vascular networks, both promoting tumor demise and restoration of normal vascular homeostasis. EGT with IL-12 is in melanoma clinical trials and nsPEFs are used in models with B16F10 melanoma in vitro and in mice. Applications of bioelectrics, using conventional electroporation and extensions of it, provide effective alternative therapies for melanoma.

  4. Impedance pneumography using textile electrodes.

    Science.gov (United States)

    Fiedler, P; Biller, S; Griebel, S; Haueisen, J

    2012-01-01

    The acquisition of physiological parameters using textile and textile-integrated sensors has become an important alternative for mobile and long-term monitoring. We analyzed to different commercially available electrically conductive textiles concerning their applicability for textile-based impedance pneumography. We immersed the textiles to four corroding solutions and observed no considerable changes in the absolute value as well as the phase shift of the material impedances. Subsequently, we performed impedance pneumography tests with different current amplitudes and frequencies. Using silver coated synthetic textile electrodes it was possible to detect the correct respiration frequency during normal, flat as well as slow, deep respiration.

  5. Microbiology and optimization of hydrogen fermentation and bioelectricity production

    Energy Technology Data Exchange (ETDEWEB)

    Makinen, A.

    2013-11-01

    yield. Pentose fermentation was accompanied by production of acetate, butyrate and formate, while in hexose fermentation the main soluble end product was lactate. In CSTR Hisarkoy enrichment culture produced H{sub 2} from xylose with the maximum average H{sub 2} yield and production rate of 1.97 mol/mol xylose and 7.3 mmol/h/L, respectively, at suboptimal temperature of 45 deg C for meso- and thermophiles. At 45 deg C microbial community consisted of only two bacterial strains affiliated to Clostridium acetobutylicum and Cirtobacter freundii. An exoeletrogenic culture was enriched on xylose from compost sample in MFCs. In enrichment phase electricity production in MFCs was accompanied with ethanol production. The main bacterium responsible of xylose degradation was xylanolytic Ruminobacillus xylanolyticum and the main bacteria responsible for electricity production were denitrifiers Paracoccus pantotrophus, Comamonas denitrificans and Alicycliphilus denitrificans. Anode potential had a significant effect on current production in MFCs. Compost enrichment culture was able to produce electricity from xylose at poised anode potential of 0.4 V vs standard hydrogen electrode (SHE) having the maximum current density and Coulombic efficiency (CE) of 1.65 A/m{sup 2} and 37 %, respectively. Lower anode potentials of 0.1 or -0.2 V vs SHE didn't lead to current production. Optimum operational parameters for bioelectricity production from xylose by compost enrichment culture were without mixing, external resistance of 100 ohm, 0.5 g/L xylose and pH 7. High current density and CE of 1.74 A/m{sup 2} and 82 %, respectively, were obtained. This is the highest CE obtained with xylose in two-chamber MFC reported in the literature. This very efficient exoelectrogenic culture was dominated by Geobacter species, including G. sulfurreducens, which were enriched on anode biofilm. Xylose fermenters, including Escherichia coli, Sphaerochaeta sp. TQ1, and Bacteroides sp. were present in

  6. Assessing Body Composition of Children and Adolescents Using Dual-Energy X-Ray Absorptiometry, Skinfolds, and Electrical Impedance

    Science.gov (United States)

    Mooney, Angela; Kelsey, Laurel; Fellingham, Gilbert W.; George, James D.; Hager, Ron L.; Myrer, J. William; Vehrs, Pat R.

    2011-01-01

    To determine the validity and reliability of percent body fat estimates in 177 boys and 154 girls between 12-17 years of age, percent body fat was assessed once using dual-energy X-ray absorptiometry and twice using the sum of two skinfolds and three bioelectrical impedance analysis devices. The assessments were repeated on 79 participants on a…

  7. Advances In Impedance Theory

    International Nuclear Information System (INIS)

    Stupakov, G.

    2009-01-01

    We review recent progress in the following areas of the impedance theory: calculation of impedance of tapers and small angle collimators; optical approximation and parabolic equation for the high-frequency impedance; impedance due to resistive inserts in a perfectly conducting pipe.

  8. Asymmetrical Grid Fault Ride-Through Strategy of Three-phase Grid-connected Inverter Considering Network Impedance Impact in Low Voltage Grid

    DEFF Research Database (Denmark)

    Guo, Xiaoqiang; Zhang, Xue; Wang, Baocheng

    2014-01-01

    This letter presents a new control strategy of threephase grid-connected inverter for the positive sequence voltage recovery and negative sequence voltage reduction under asymmetrical grid faults. Unlike the conventional control strategy based on an assumption that the network impedance is mainly...... inductive, the proposed control strategy is more flexible and effective by considering the network impedance impact, which is of great importance for the high penetration of grid-connected renewable energy systems into low-voltage grids. The experimental tests are carried out to validate the effectiveness...... of the proposed solution for the flexible voltage support in a low-voltage grid, where thenetwork impedance is mainly resistive....

  9. Evaluation of electrical broad bandwidth impedance spectroscopy as a tool for body composition measurement in cows in comparison with body measurements and the deuterium oxide dilution method.

    Science.gov (United States)

    Schäff, C T; Pliquett, U; Tuchscherer, A; Pfuhl, R; Görs, S; Metges, C C; Hammon, H M; Kröger-Koch, C

    2017-05-01

    Body fatness and degree of body fat mobilization in cows vary enormously during their reproduction cycle and influence energy partitioning and metabolic adaptation. The objective of the study was to test bioelectrical impedance spectroscopy (BIS) as a method for predicting fat depot mass (FDM), in living cows. The FDM is defined as the sum of subcutaneous, omental, mesenteric, retroperitoneal, and carcass fat mass. Bioelectrical impedance spectroscopy is compared with the prediction of FDM from the deuterium oxide (DO) dilution method and from body conformation measurements. Charolais × Holstein Friesian (HF; = 18; 30 d in milk) crossbred cows and 2 HF (lactating and nonlactating) cows were assessed by body conformation measurements, BIS, and the DO dilution method. The BCS of cows was a mean of 3.68 (SE 0.64). For the DO dilution method, a bolus of 0.23 g/kg BW DO (60 atom%) was intravenously injected and deuterium (D) enrichment was analyzed in plasma and whey by stabile isotope mass spectrometry, and total body water content was calculated. Impedance measurement was performed using a 4-electrode interface and time domain-based measurement system consisting of a voltage/current converter for applying current stimulus and an amplifier for monitoring voltage across the sensor electrodes. For the BIS, we used complex impedances over three frequency decades that delivers information on intra- and extracellular water and capacity of cell membranes. Impedance data (resistance of extra- and intracellular space, cell membrane capacity, and phase angle) were extracted 1) by simple curve fit to extract the resistance at direct current and high frequency and 2) by using an electrical equivalent circuit. Cows were slaughtered 7 d after BIS and D enrichment measurements and dissected for the measurement of FDM. Multiple linear regression analyses were performed to predict FDM based on data obtained from body conformation measurements, BIS, and D enrichment, and applied

  10. Electrical impedance spectroscopy (EIS)-based evaluation of biological tissue phantoms to study multifrequency electrical impedance tomography (Mf-EIT) systems

    KAUST Repository

    Bera, Tushar Kanti

    2016-03-18

    Abstract: Electrical impedance tomography (EIT) phantoms are essential for the calibration, comparison and evaluation of the EIT systems. In EIT, the practical phantoms are typically developed based on inhomogeneities surrounded by a homogeneous background to simulate a suitable conductivity contrast. In multifrequency EIT (Mf-EIT) evaluation, the phantoms must be developed with the materials which have recognizable or distinguishable impedance variations over a wide range of frequencies. In this direction the impedance responses of the saline solution (background) and a number vegetable and fruit tissues (inhomogeneities) are studied with electrical impedance spectroscopy (EIS) and the frequency responses of bioelectrical impedance and conductivity are analyzed. A number of practical phantoms with different tissue inhomogeneities and different inhomogeneity configurations are developed and the multifrequency impedance imaging is studied with the Mf-EIT system to evaluate the phantoms. The conductivity of the vegetable inhomogeneities reconstructed from the EIT imaging is compared with the conductivity values obtained from the EIS studies. Experimental results obtained from multifrequency EIT reconstruction demonstrate that the electrical impedance of all the biological tissues inhomogenity decreases with frequency. The potato tissue phantom produces better impedance image in high frequency ranges compared to the cucumber phantom, because the cucumber impedance at high frequency becomes lesser than that of the potato at the same frequency range. Graphical Abstract: [Figure not available: see fulltext.] © 2016 The Visualization Society of Japan

  11. Integrated assessment of bioelectricity technology options

    International Nuclear Information System (INIS)

    Thornley, Patricia; Upham, Paul; Huang, Ye; Rezvani, Sina; Brammer, John; Rogers, John

    2009-01-01

    Power generation from biomass is a sustainable energy technology which can contribute to substantial reductions in greenhouse gas emissions, but with greater potential for environmental, economic and social impacts than most other renewable energy technologies. It is important therefore in assessing bioenergy systems to take account of not only technical, but also environmental, economic and social parameters on a common basis. This work addresses the challenge of analysing, quantifying and comparing these factors for bioenergy power generation systems. A life-cycle approach is used to analyse the technical, environmental, economic and social impacts of entire bioelectricity systems, with a number of life-cycle indicators as outputs to facilitate cross-comparison. The results show that similar greenhouse gas savings are achieved with the wide variety of technologies and scales studied, but land-use efficiency of greenhouse gas savings and specific airborne emissions varied substantially. Also, while specific investment costs and electricity costs vary substantially from one system to another the number of jobs created per unit of electricity delivered remains roughly constant. Recorded views of stakeholders illustrate that diverging priorities exist for different stakeholder groups and this will influence appropriate choice of bioenergy systems for different applications

  12. The use of bioelectrical impedance to detect excess visceral and subcutaneous fat

    OpenAIRE

    Fernandes, Rômulo A.; Rosa, Clara S. C.; Buonani, Camila; Oliveira, Arli R. de; Freitas Júnior, Ismael F.

    2007-01-01

    OBJETIVO: Analisar a relação e o desempenho da impedância bioelétrica na indicação do excesso de gordura visceral e sobrepeso/obesidade em jovens brasileiros. MÉTODOS: A amostra foi composta por 811 jovens de ambos os sexos (de 11 a 17 anos). A identificação do estado nutricional foi baseada no valor da dobra cutânea tricipital e gordura relativa (impedância bioelétrica) e no excesso de gordura visceral no valor da circunferência de cintura. A análise estatística utilizou valores médios, desv...

  13. Impact of hemodialysis on dual X-ray absorptiometry, bioelectrical impedance measurements, and anthropometry

    DEFF Research Database (Denmark)

    Abrahamsen, Bo; Hansen, T B; Høgsberg, I M

    1996-01-01

    Dual X-ray absorptiometry (DXA) performs noninvasive assessment of bone and soft tissue with high precision. However, soft tissue algorithms assume that 73.2% of the lean body mass is water, a potential source of error in fluid retention. We evaluated DXA (model QDR-2000; Hologic Inc, Waltham, MA...

  14. Application of body mass index adjusted for fat mass (BMIfat) obtained by bioelectrical impedance in adults.

    Science.gov (United States)

    Mialich, Mirele Savegnago; Martinez, Edson Zangiacomi; Jordão Junior, Alceu Afonso

    2014-08-01

    Body mass index (BMI) has been one of the methods most frequently used for diagnose obesity, but it isn't consider body composition. This study intends to apply one new adiposity index, the BMI adjusted for fat mass (BMIfat) developed by Mialich et al. (2011), in a adult Brazilian sample. A cross-sectional study with 501 individuals of both genders (366 women, 135 men) aged 17 to 38 years and mean age was 20.4 ± 2.8 years, mean weight 63.0 ± 13.5 kg, mean height 166.9 ± 9.0 cm, and BMI 22.4 ± 3.4 kg/m2. High and satisfactory R2 values were obtained, i.e., 91.1%, 91.9% and 88.8% for the sample as a whole and for men and women, respectively. Considering this BMIfat were developed new ranges, as follows: 1.35 to 1.65 (nutritional risk for malnutrition), > 1.65 and ≤2.0 (normal weight) and > 2.0 (obesity). The BMIfat had a more accurate capacity of detecting obese individuals (0.980. 0.993, 0.974) considering the sample as a whole and women and men, respectively, compared to the traditional BMI (0.932, 0.956, 0.95). Were also defined new cut-off points for the traditional BMI for the classification of obesity, i.e.: 25.24 kg/m2 and 28.38 kg/m2 for men and women, respectively. The BMIfat was applied for the present population and can be adopted in clinical practice. Further studies are needed to determine its application to different ethnic groups and to compare this index to others previously described in the scientific literature. Copyright AULA MEDICA EDICIONES 2014. Published by AULA MEDICA. All rights reserved.

  15. Bioelectrical impedance analysis (BIA) for sarcopenic obesity (SO) diagnosis in young female subjects

    Science.gov (United States)

    González-Correa, C. H.; Caicedo-Eraso, J. C.; S, Villada-Gomez J.

    2013-04-01

    Sarcopenia is defined as a loss of muscle mass depending of ageing and affecting physical function (definition A). A new definition considers excluding mass reduction criterion (definition B). Obesity is pandemic and occurs at all ages. Sarcopenic obesity (SO) implies both processes. The purpose of this study was to compare the results obtained after applying these 2 definitions in 66 aged 22 ± 2.8 years overweight or obese young college women. Percentage body fat (%BF) and skeletal mass index (SMI) were estimated by BIA, muscle function by handgrip strength test (HGS) and physical performance by Harvard step test (HST). There were 9.1% and 90.9% overweight or obese subjects. Twenty nine subjects (43.9%) had decreased HGS and 22 (33.3%) had impaired physical performance. One obese subject (1.5%) met the criteria for sarcopenic obesity by definition A and 9 (13.6%) by definition B. Although a linear regression (α obese, the problematic of SO will be found earlier in life.

  16. Predictive capacity of different bioelectrical impedance analysis devices, with and without protocol, in evaluation of adolescents

    Directory of Open Access Journals (Sweden)

    Vivian Siqueira Santos Gonçalves

    2013-11-01

    Conclusion: BIA is capable of predicting alterations in adolescents’ body composition. When it is impossible to perform the assessment with a protocol, its results may be useful in population studies.

  17. Sensitivity field distributions for segmental bioelectrical impedance analysis based on real human anatomy

    Science.gov (United States)

    Danilov, A. A.; Kramarenko, V. K.; Nikolaev, D. V.; Rudnev, S. G.; Salamatova, V. Yu; Smirnov, A. V.; Vassilevski, Yu V.

    2013-04-01

    In this work, an adaptive unstructured tetrahedral mesh generation technology is applied for simulation of segmental bioimpedance measurements using high-resolution whole-body model of the Visible Human Project man. Sensitivity field distributions for a conventional tetrapolar, as well as eight- and ten-electrode measurement configurations are obtained. Based on the ten-electrode configuration, we suggest an algorithm for monitoring changes in the upper lung area.

  18. Prediction of percentage body fat from anthropometry and bioelectrical impedance in Singaporean and Beijing Chinese

    NARCIS (Netherlands)

    Deurenberg, P.; Deurenberg-Yap, M.; Jingzhong Wang,; Fu Po Lin,; Schmidt, G.

    2000-01-01

    Body composition was measured in 205 male and female Beijing Chinese and in 148 male and female Singaporean Chinese, age 34 (mean) (range 18-68) years and body mass index (BMI) 22.3 (15.9-38.5) kg/m 2. In Beijing Siri's two-compartment model based on densitometry was used as a reference technique

  19. Bioelectrical impedance analysis (BIA) equations validation against hydrodensitometry in a Colombian population

    Science.gov (United States)

    Caicedo-Eraso, J. C.; Gonzalez-Correa, C. A.; Gonzalez-Correa, C. H.

    2013-04-01

    Several studies have shown that the accuracy of BIA results depends of ethnicity, age, gender, hormonal and genetic variations and, so far, there are not specific equations for Colombian population. The purpose was to evaluate reported BIA equations to determine their usefulness in body composition assessment in young females from Colombia using hydrodensitometry as the reference method. A sample of 30 young females was evaluated. Inclusion and exclusion criteria were defined to minimize the variability of BIA. Height, weight, multi-frequency BIA, residual lung volume (RV) and underwater weight (UWW) were measured. Five BIA equations met the inclusion criteria of this study. Three equations overestimated and two equations underestimated body fat (BF). Paired Student t-test and Bland and Altman analysis (p<0.05) showed significant differences in four BIA equations. However, all standard error of estimate (SEE) to BF was greater than 2.7 kg. This study showed that the five selected BIA equations are not valid for estimation of body composition in young females from Colombia. It is recommended to develop BIA equations to improve BF fat assessment in our population.

  20. Bioelectrical impedance vectorial analysis and nutritional status of older women according to body mass index

    Science.gov (United States)

    Longitudinal studies, both epidemiological and clinical, have shown that elderly with high body mass index (BMI) are able to better face stressing factors, and have better survival rate as consequence. The aim of the present study was to evaluate if higher BMI values were associated with improved nu...

  1. Bioelectrical impedance analysis (BIA): a proposal for standardization of the classical method in adults

    Science.gov (United States)

    González-Correa, C. H.; Caicedo-Eraso, J. C.

    2012-12-01

    The accuracy of BIA measurements is limited by different sources of error such as physical model, cross sectional area, ethnicity, body hydration, age and level of body fat among other variables. Equation for each population is required as they can produce overestimation when manufacturer's equations are used. The classical measurements hand to foot has shown better correlation against hydrodensitometry than foot to foot or hand to hand. However there is a lack for an accepted standard of BIA procedures. This is compounded when there is not a good report of the BIA study's methodology; hence the comparability between the results is poor and reduces the reliability of the method. Perhaps, standardization of methods would be the first step for BIA studies to move forward and subsequently improve its accuracy. Standardized procedures could also minimize the impact of these variables on studies results. The aim of this study was to propose a protocol as a checklist to standardize BIA procedures and produce comparable results from future studies performed with the classic hand-foot configuration in adults.

  2. Bioelectrical Impedance Measurement for Predicting Treatment Outcome in Patients With Newly Diagnosed Acute Leukemia

    Science.gov (United States)

    2018-01-24

    Acute Undifferentiated Leukemia; Adult Acute Myeloid Leukemia With 11q23 (MLL) Abnormalities; Adult Acute Myeloid Leukemia With Del(5q); Adult Acute Myeloid Leukemia With Inv(16)(p13;q22); Adult Acute Myeloid Leukemia With t(15;17)(q22;q12); Adult Acute Myeloid Leukemia With t(16;16)(p13;q22); Adult Acute Myeloid Leukemia With t(8;21)(q22;q22); Mast Cell Leukemia; Myeloid/NK-cell Acute Leukemia; Untreated Adult Acute Lymphoblastic Leukemia; Untreated Adult Acute Myeloid Leukemia

  3. The validity and accuracy in foot-to-foot bioelectrical impedance ...

    African Journals Online (AJOL)

    The ZF-F value was 481.85 ± 63.37 ohm in male and 554.35 ± 74.97 ohm in female. The ZH-F value was 586.82 ± 81.56 ohm in male and 703.28 ± 97.70 ohm in female. Regression equations for ZF-F and ZH-F were ZF-F = 0.926 ZH-F - 63.093, (R = 0.85) in male and ZF-F = 0.909 ZH-F - 86.673 (R = 0.86) in female. The fat ...

  4. Pengembangan Bioelectrical Impedance Sebagai Control Commands Pengaturan Kecepatan Gerak Kursi Roda Dengan Metoda PID Controller

    Directory of Open Access Journals (Sweden)

    Juli Sardi

    2014-09-01

    Full Text Available In the present study, bioimpedance signals of human body was utilized to control speed of a wheelchair movement. A bioimpedance is electrically passive part contained the body tissues. The research is one of alternative solutions for patients with paralysis of the upper and lower limb. Firstly, design of system of the research consisted of bioimpedance measuring instruments and a mechanical design of the wheelchair. Bioimpedance measurement was performed by injecting a sinusoidal current source of 0.5 mArms with a frequency of 50 kHz to muscle tissue (shoulder to obtain the output voltage in the range of 0-5 Vdc. With impulse and manual thresholding methods, the voltage signal was classified into several controls command to adjust the speed and direction of the wheelchair control based on PID Controller. The experimental result of the research was realization of bioimpedance signal that used as a reference to control the direction and speed of the wheelchair with a success rate of 86.7 %. A wheelchair velocity was classified into three types of motion, namely slow, medium and fast. Slow speed has a rated speed of 30 Cm/s, medium speed value speed of 40 Cm/s and fast speed value of 50 Cm/s. The wheelchair can also turn to the left and the right in accordance with the wishes of wheelchair user beside to moving forward.

  5. Bioelectrical impedance analysis (BIA) for sarcopenic obesity (SO) diagnosis in young female subjects

    International Nuclear Information System (INIS)

    González-Correa, C H; Caicedo-Eraso, J C; Villada-Gomez J S

    2013-01-01

    Sarcopenia is defined as a loss of muscle mass depending of ageing and affecting physical function (definition A). A new definition considers excluding mass reduction criterion (definition B). Obesity is pandemic and occurs at all ages. Sarcopenic obesity (SO) implies both processes. The purpose of this study was to compare the results obtained after applying these 2 definitions in 66 aged 22 ± 2.8 years overweight or obese young college women. Percentage body fat (%BF) and skeletal mass index (SMI) were estimated by BIA, muscle function by handgrip strength test (HGS) and physical performance by Harvard step test (HST). There were 9.1% and 90.9% overweight or obese subjects. Twenty nine subjects (43.9%) had decreased HGS and 22 (33.3%) had impaired physical performance. One obese subject (1.5%) met the criteria for sarcopenic obesity by definition A and 9 (13.6%) by definition B. Although a linear regression (α 2 = 0.094, 0.037 and 0.275 respectively) it was observed a tendency for HGS, HST and SMI deterioration when %BF increases. However, other confounding factors must be investigated. Probably as the population gets more obese, the problematic of SO will be found earlier in life.

  6. Application of phase angle for evaluation of the nutrition status of patients with anorexia nervosa.

    Science.gov (United States)

    Małecka-Massalska, Teresa; Popiołek, Joanna; Teter, Mariusz; Homa-Mlak, Iwona; Dec, Mariola; Makarewicz, Agata; Karakuła-Juchnowicz, Hanna

    2017-12-30

    The evaluation of the nutrition status of patients has been the subject of interest of many scientific disciplines. Any deviation from normal values is a serious clinical problem. There are multiple nutrition status evaluation methods used including diet history, scales and questionnaires, physical examination, anthropometric measurements, biochemical measurements, function tests, as well as bioelectric impedance analysis or adipometry. Phase angle, obtained by means of bioelectric impedance analysis, is another parameter that is being more and more frequently applied in nutrition status monitoring. It is proportional to body cell mass. Its direct correlation with the cellular nutrition status has been documented. High phase angle values signify well-being, while low phase angle values indicate poor condition of cells. The purpose of this paper was to review the current state of knowledge about the application of phase angle in evaluation and monitoring of the nutrition status of patients with anorexia nervosa on the basis of available literature. It was proven that the phase angle values in patients with anorexia nervosa are much lower compared to healthy people. Detailed observations showed phase angle value increase in the course of treatment. The relevance of the commonly used body mass index (BMI) has been questioned due to significant degree of generalization in the nutrition status evaluation. Thus, there is a need for new, objective parameters for nutrition status evaluation, which will assist in the treatment and monitoring of patients in a more meaningful and reliable way. The existing independent studies equivocally confirm the usefulness of phase angle in the evaluation of nutrition status of patients with anorexia nervosa and its broader application in clinical practice is only a matter of time. However, these are merely attempts and they have not yet found wider application in clinical practice in the treatment of anorexia nervosa.

  7. Impedance plethysmography of thoracic region: impedance cardiography.

    Directory of Open Access Journals (Sweden)

    Deshpande A

    1990-10-01

    Full Text Available Impedance plethysmograms were recorded from thoracic region in 254 normal subjects, 183 patients with coronary artery disease, 391 patients with valvular heart disease and 107 patients with congenital septal disorder. The data in 18 normal subjects and 55 patients showed that basal impedance decreases markedly during exercise in patients with ischaemic heart disease. Estimation of cardiac index by this technique in a group of 99 normal subjects has been observed to be more consistent than that of the stroke volume. Estimation of systolic time index from impedance plethysmograms in 34 normal subjects has been shown to be as reliable as that from electrocardiogram, phonocardiogram and carotid pulse tracing. Changes in the shape of plethysmographic waveform produced by valvular and congenital heart diseases are briefly described and the role of this technique in screening cardiac patients has been highlighted.

  8. Spectroscopy study of the dynamics of the transencephalic electrical impedance in the perinatal brain during hypoxia.

    Science.gov (United States)

    Seoane, Fernando; Lindecrantz, Kaj; Olsson, Torsten; Kjellmer, Ingemar; Flisberg, Anders; Bågenholm, Ralph

    2005-10-01

    Hypoxia/ischaemia is the most common cause of brain damage in neonates. Thousands of newborn children suffer from perinatal asphyxia every year. The cells go through a response mechanism during hypoxia/ischaemia, to maintain the cellular viability and, as a response to the hypoxic/ischaemic insult, the composition and the structure of the cellular environment are altered. The alterations in the ionic concentration of the intra- and extracellular and the consequent cytotoxic oedema, cell swelling, modify the electrical properties of the constituted tissue. The changes produced can be easily measured using electrical impedance instrumentation. In this paper, we report the results from an impedance spectroscopy study on the effects of the hypoxia on the perinatal brain. The transencephalic impedance, both resistance and reactance, was measured in newborn piglets using the four-electrode method in the frequency range from 20 kHz to 750 kHz and the experimental results were compared with numerical results from a simulation of a suspension of cells during cell swelling. The experimental results make clear the frequency dependence of the bioelectrical impedance, confirm that the variation of resistance is more sensitive at low than at high frequencies and show that the reactance changes substantially during hypoxia. The resemblance between the experimental and numerical results proves the validity of modelling tissue as a suspension of cells and confirms the importance of the cellular oedema process in the alterations of the electrical properties of biological tissue. The study of the effects of hypoxia/ischaemia in the bioelectrical properties of tissue may lead to the development of useful clinical tools based on the application of bioelectrical impedance technology.

  9. Effect of photostimulation on maize leaves’ bioelectrical response

    Directory of Open Access Journals (Sweden)

    M. P. Motsnyj

    2011-06-01

    Full Text Available Dynamics of the maize leaves’ biopotentials evoked by white, blue, green and red light stimuli with an intensity of 90 Lx illumination is analyzed. Qualitative similarity in dynamics of plant’s bioelectrical response to white and colored stimuli is determined. Hyperpolarization levels are quantitatively estimated for each experimental series. Dependence of the total hyperpolarization levels on the photostimulus wave length is detected. Mean amplitude of the hyperpolarization potentials lessens when the wave length decreases: from 57.7 mV under the red light to 27.7 mV under the blue one. Probable forms of bioelectrical response initiation in photostimulated plants are analyzed.

  10. A new index of hemodialysis adequacy: clearance x dialysis time / bioelectrical resistance.

    Science.gov (United States)

    Basile, Carlo; Vernaglione, Luigi; Lomonte, Carlo; Bellizzi, Vincenzo; Dambrosio, Nicola; Di Iorio, Biagio

    2010-01-01

    Kt/V urea was established as an index of hemodialysis (HD) adequacy. The use of V urea (as derived by the Watson et al formulae) as a normalizing factor has been questioned, and alternative parameters such as body weight 0.67 (W 0.67), body surface area (BSA), resting energy expenditure (REE), high metabolic rate organ (HMRO) mass and liver size (LV) have been proposed (respective HD adequacy indices: Kt/W 0.67, Kt/BSA, Kt/REE, Kt/HMRO and Kt/LV). The present study aimed to calculate the 6 previously described normalizing factors (all obtained utilizing anthropometric variables) and to measure bioelectrical resistance (R), an independent and directly achievable biological parameter, in 481 white, disease-free individuals and 270 white prevalent HD patients, pair-matched by age, body weight and height, after stratification by sex. Further, we aimed to evaluate the effect of substituting BSA, W 0.67, REE, HMRO, LV and R for V urea as denominator in Kt/V urea on the distribution of target dialysis dose in a cohort of 1,058 white prevalent HD patients. All individuals underwent 1 single-frequency bioelectrical impedance measurement, on the nondominant side of the body, injecting 800 μA at 50 kHz alternating sinusoidal current with a standard tetrapolar technique. When comparing pair-matched disease-free men and women with HD men and women, respectively, only R was statistically significantly different (pcalculations which utilize anthropometric variables. In contrast, R is a biological parameter which can be directly measured in the clinical setting by means of a simple, low-cost, fast and repeatable procedure. Even though Kt/R is probably the most appropriate method for scaling dialysis dose among those evaluated in the present study, further work is required to develop these concepts and translate them into rigorous outcome-based adequacy targets suitable for clinical usage.

  11. Nonsynchronous Noncommensurate Impedance Transformers

    DEFF Research Database (Denmark)

    Zhurbenko, Vitaliy; Kim, K

    2012-01-01

    Nonsynchronous noncommensurate impedance transformers consist of a combination of two types of transmission lines: transmission lines with a characteristic impedance equal to the impedance of the source, and transmission lines with a characteristic impedance equal to the load. The practical...... advantage of such transformers is that they can be constructed using sections of transmission lines with a limited variety of characteristic impedances. These transformers also provide comparatively compact size in applications where a wide transformation ratio is required. This paper presents the data...... which allows to estimate the achievable total electrical length and in-band reflection coefficient for transformers consisting of up to twelve transmission line sections in the range of transformation ratios r = 1:5 to 10 and bandwidth ratios  = 2 to 20. This data is obtained using wave transmission...

  12. Bioelectric Control of a 757 Class High Fidelity Aircraft Simulation

    Science.gov (United States)

    Jorgensen, Charles; Wheeler, Kevin; Stepniewski, Slawomir; Norvig, Peter (Technical Monitor)

    2000-01-01

    This paper presents results of a recent experiment in fine grain Electromyographic (EMG) signal recognition, We demonstrate bioelectric flight control of 757 class simulation aircraft landing at San Francisco International Airport. The physical instrumentality of a pilot control stick is not used. A pilot closes a fist in empty air and performs control movements which are captured by a dry electrode array on the arm, analyzed and routed through a flight director permitting full pilot outer loop control of the simulation. A Vision Dome immersive display is used to create a VR world for the aircraft body mechanics and flight changes to pilot movements. Inner loop surfaces and differential aircraft thrust is controlled using a hybrid neural network architecture that combines a damage adaptive controller (Jorgensen 1998, Totah 1998) with a propulsion only based control system (Bull & Kaneshige 1997). Thus the 757 aircraft is not only being flown bioelectrically at the pilot level but also demonstrates damage adaptive neural network control permitting adaptation to severe changes in the physical flight characteristics of the aircraft at the inner loop level. To compensate for accident scenarios, the aircraft uses remaining control surface authority and differential thrust from the engines. To the best of our knowledge this is the first time real time bioelectric fine-grained control, differential thrust based control, and neural network damage adaptive control have been integrated into a single flight demonstration. The paper describes the EMG pattern recognition system and the bioelectric pattern recognition methodology.

  13. Production of bio-electricity during wastewater treatment using a ...

    African Journals Online (AJOL)

    Production of bio-electricity during wastewater treatment using a single chamber microbial fuel cell. ... water treatment with production of sustainable energy. The power ... it is possible to generate electricity using bacteria while accomplishing waste water treatment in process based on microbial fuel cell technologies.

  14. bioelectricity production from cassava mill effluents using microbial

    African Journals Online (AJOL)

    user

    2016-04-02

    Apr 2, 2016 ... new form of renewable and sustainable technology for electricity generation as it recovers energy from renewable ... energy generation. Bioelectricity is an electric current that is generated by a variety of biological processes and generally range from one to few ..... Availability of complex mixed cultures.

  15. Compost in plant microbial fuel cell for bioelectricity generation

    NARCIS (Netherlands)

    Moqsud, M.A.; Yoshitake, J.; Bushra, Q.S.; Hyodo, M.; Omine, K.; Strik, D.P.B.T.B.

    2015-01-01

    Recycling of organic waste is an important topic in developing countries as well as developed countries. Compost from organic waste has been used for soil conditioner. In this study, an experiment has been carried out to produce green energy (bioelectricity) by using paddy plant microbial fuel cells

  16. Impedance and Collective Effects

    CERN Document Server

    Metral, E; Rumolo, R; Herr, W

    2013-01-01

    This document is part of Subvolume C 'Accelerators and Colliders' of Volume 21 'Elementary Particles' of Landolt-Börnstein - Group I 'Elementary Particles, Nuclei and Atoms'. It contains the Chapter '4 Impedance and Collective Effects' with the content: 4 Impedance and Collective Effects Introduction 4.1 Space Charge 4.2 Wake Fields and Impedances 4.3 Coherent Instabilities 4.4 Landau Damping 4.5 Two-Stream Effects (Electron Cloud and Ions) 4.6 Beam-Beam Effects 4.7 Numerical Modelling

  17. Performance of Microbial Fuel Cell to Generate Bioelectricity Uses Different Kinds of Electrode in the Fish Processing Wastewater

    Directory of Open Access Journals (Sweden)

    Bustami Ibrahim

    2017-08-01

    Full Text Available Microbial Fuel Cell (MFC is one of the alternative technologies which can convert chemical energy to electrical energy through a catalytic reaction using microorganisms. The technology can be implemented for wastewater handling such as fish processing wastewater which contains highly in organic substances. The research objective was to measure the performance of MFC system using fishery processing wastewater in order to generate bioelectricity and to reduce its organic pollution load within a different material of the electrode. The electrode materials used were aluminum, iron, carbon graphite, and also the combination of aluminum and carbon graphite. The research carried out in three phases: production of fishery wastewater, assembly of MFC single chamber system and measurement of the bioelectricity produced. The bioelectricity power resulted during 120 hours of observation were 0.23V for aluminum, 0.17V for iron, 0.19V for carbon graphite, and 0.34V for the combination between aluminum and carbon graphite averagely. The MFC system can also  decrease the organic load parameter of wastewater as much as total Nitrogen was 61%, BOD 30.11%, COD 59.34%, and total Nitrogen Ammonia 12.45%. The increasing of activated sludge biomass occurred on the last observation with MLSS and MLVSS values respectively 7,066.67 mg/L and 6,100 mg/L.

  18. LHC Bellows Impedance Calculations

    CERN Document Server

    Dyachkov, M

    1997-01-01

    To compensate for thermal expansion the LHC ring has to accommodate about 2500 bellows which, together with beam position monitors, are the main contributors to the LHC broad-band impedance budget. In order to reduce this impedance to an acceptable value the bellows have to be shielded. In this paper we compare different designs proposed for the bellows and calculate their transverse and longitudinal wakefields and impedances. Owing to the 3D geometry of the bellows, the code MAFIA was used for the wakefield calculations; when possible the MAFIA results were compared to those obtained with ABCI. The results presented in this paper indicate that the latest bellows design, in which shielding is provided by sprung fingers which can slide along the beam screen, has impedances smaller tha those previously estimated according to a rather conservative scaling of SSC calculations and LEP measurements. Several failure modes, such as missing fingers and imperfect RF contact, have also been studied.

  19. Impedance and component heating

    CERN Document Server

    Métral, E; Mounet, N; Pieloni, T; Salvant, B

    2015-01-01

    The impedance is a complex function of frequency, which represents, for the plane under consideration (longitudinal, horizontal or vertical), the force integrated over the length of an element, from a “source” to a “test” wave, normalized by their charges. In general, the impedance in a given plane is a nonlinear function of the test and source transverse coordinates, but it is most of the time sufficient to consider only the first few linear terms. Impedances can influence the motion of trailing particles, in the longitudinal and in one or both transverse directions, leading to energy loss, beam instabilities, or producing undesirable secondary effects such as excessive heating of sensitive components at or near the chamber wall, called beam-induced RF heating. The LHC performance limitations linked to impedances encountered during the 2010-2012 run are reviewed and the currently expected situation during the HL-LHC era is discussed.

  20. Electrical Impedance Tomography Technology

    Data.gov (United States)

    National Aeronautics and Space Administration — The goal for the Electrical Impedance Tomography Technology (EITT) project is to develop a reliable portable, lightweight device providing two-dimensional...

  1. Impedance Analysis of SOGI-FLL-Based Grid Synchronization

    DEFF Research Database (Denmark)

    Yi, Hao; Wang, Xiongfei; Blaabjerg, Frede

    2017-01-01

    The latest research has pointed out that the Phase-Locked Loop (PLL) plays an important role in shaping the impedance of grid-connected converters, yet most of the works so far merely focus on the synchronous reference-frame PLL. Alternatively, this letter presents the impedance analysis of the S......The latest research has pointed out that the Phase-Locked Loop (PLL) plays an important role in shaping the impedance of grid-connected converters, yet most of the works so far merely focus on the synchronous reference-frame PLL. Alternatively, this letter presents the impedance analysis...

  2. The LEP impedance model

    Energy Technology Data Exchange (ETDEWEB)

    Zotter, B. [European Organization for Nuclear Research, Geneva (Switzerland)

    1996-08-01

    This report describes a number of measurements and computations of the impedance of the Large Electron Positron collider LEP at CERN. The work has been performed over several years, together with D. Brandt, K. Cornelis, A. Hofmann, G. Sabbi and many others. The agreement between measurements of single bunch instabilities on the machine and computer simulations is in general excellent and gives confidence in the impedance model used. (author)

  3. Impeded Dark Matter

    International Nuclear Information System (INIS)

    Kopp, Joachim; Liu, Jia; Slatyer, Tracy R.; Wang, Xiao-Ping; Xue, Wei

    2016-01-01

    We consider dark matter models in which the mass splitting between the dark matter particles and their annihilation products is tiny. Compared to the previously proposed Forbidden Dark Matter scenario, the mass splittings we consider are much smaller, and are allowed to be either positive or negative. To emphasize this modification, we dub our scenario “Impeded Dark Matter”. We demonstrate that Impeded Dark Matter can be easily realized without requiring tuning of model parameters. For negative mass splitting, we demonstrate that the annihilation cross-section for Impeded Dark Matter depends linearly on the dark matter velocity or may even be kinematically forbidden, making this scenario almost insensitive to constraints from the cosmic microwave background and from observations of dwarf galaxies. Accordingly, it may be possible for Impeded Dark Matter to yield observable signals in clusters or the Galactic center, with no corresponding signal in dwarfs. For positive mass splitting, we show that the annihilation cross-section is suppressed by the small mass splitting, which helps light dark matter to survive increasingly stringent constraints from indirect searches. As specific realizations for Impeded Dark Matter, we introduce a model of vector dark matter from a hidden SU(2) sector, and a composite dark matter scenario based on a QCD-like dark sector.

  4. Impeded Dark Matter

    Energy Technology Data Exchange (ETDEWEB)

    Kopp, Joachim; Liu, Jia [PRISMA Cluster of Excellence & Mainz Institute for Theoretical Physics,Johannes Gutenberg University,Staudingerweg 7, 55099 Mainz (Germany); Slatyer, Tracy R. [Center for Theoretical Physics, Massachusetts Institute of Technology,Cambridge, MA 02139 (United States); Wang, Xiao-Ping [PRISMA Cluster of Excellence & Mainz Institute for Theoretical Physics,Johannes Gutenberg University,Staudingerweg 7, 55099 Mainz (Germany); Xue, Wei [Center for Theoretical Physics, Massachusetts Institute of Technology,Cambridge, MA 02139 (United States)

    2016-12-12

    We consider dark matter models in which the mass splitting between the dark matter particles and their annihilation products is tiny. Compared to the previously proposed Forbidden Dark Matter scenario, the mass splittings we consider are much smaller, and are allowed to be either positive or negative. To emphasize this modification, we dub our scenario “Impeded Dark Matter”. We demonstrate that Impeded Dark Matter can be easily realized without requiring tuning of model parameters. For negative mass splitting, we demonstrate that the annihilation cross-section for Impeded Dark Matter depends linearly on the dark matter velocity or may even be kinematically forbidden, making this scenario almost insensitive to constraints from the cosmic microwave background and from observations of dwarf galaxies. Accordingly, it may be possible for Impeded Dark Matter to yield observable signals in clusters or the Galactic center, with no corresponding signal in dwarfs. For positive mass splitting, we show that the annihilation cross-section is suppressed by the small mass splitting, which helps light dark matter to survive increasingly stringent constraints from indirect searches. As specific realizations for Impeded Dark Matter, we introduce a model of vector dark matter from a hidden SU(2) sector, and a composite dark matter scenario based on a QCD-like dark sector.

  5. Heterogeneous silicon mesostructures for lipid-supported bioelectric interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Yuanwen; Carvalho-de-Souza, João L.; Wong, Raymond C. S.; Luo, Zhiqiang; Isheim, Dieter; Zuo, Xiaobing; Nicholls, Alan W.; Jung, Il Woong; Yue, Jiping; Liu, Di-Jia; Wang, Yucai; De Andrade, Vincent; Xiao, Xianghui; Navrazhnykh, Luizetta; Weiss, Dara E.; Wu, Xiaoyang; Seidman, David N.; Bezanilla, Francisco; Tian, Bozhi

    2016-06-27

    Silicon-based materials have widespread application as biophysical tools and biomedical devices. Here we introduce a biocompatible and degradable mesostructured form of silicon with multi-scale structural and chemical heterogeneities. The material was synthesized using mesoporous silica as a template through a chemical vapour deposition process. It has an amorphous atomic structure, an ordered nanowire-based framework and random submicrometre voids, and shows an average Young’s modulus that is 2–3 orders of magnitude smaller than that of single-crystalline silicon. In addition, we used the heterogeneous silicon mesostructures to design a lipid-bilayer-supported bioelectric interface that is remotely controlled and temporally transient, and that permits non-genetic and subcellular optical modulation of the electrophysiology dynamics in single dorsal root ganglia neurons. Our findings suggest that the biomimetic expansion of silicon into heterogeneous and deformable forms can open up opportunities in extracellular biomaterial or bioelectric systems.

  6. Acoustic Impedance Measurement for Underground Surfaces.

    Science.gov (United States)

    Cockcroft, Paul William

    Available from UMI in association with The British Library. Requires signed TDF. This thesis investigates the measurement of acoustic impedance for surfaces likely to be found in underground coal mines. By introducing the concepts of industrial noise, the effects of noise on the ear and relevant legislation the need for the protection of workers can be appreciated. Representative acoustic impedance values are vital as input for existing computer models that predict sound levels in various underground environments. These enable the mining engineer to predict the noise level at any point within a mine in the vicinity of noisy machinery. The concepts of acoustic intensity and acoustic impedance are investigated and different acoustic impedance measurement techniques are detailed. The possible use of either an impedance tube or an intensity meter for these kinds of measurements are suggested. The problems with acoustic intensity and acoustic impedance measurements are discussed with reference to the restraints that an underground environment imposes on any measurement technique. The impedance tube method for work in an acoustics laboratory is shown and the theory explained, accompanied by a few representative results. The use of a Metravib intensity meter in a soundproof chamber to gain impedance values is explained in detail. The accompanying software for the analysis of the two measured pressure signals is shown as well as the actual results for a variety of test surfaces. The use of a Nagra IV-SJ tape recorder is investigated to determine the effect of recording on the measurement and subsequent analysis of the input signals, particularly with reference to the phase difference introduced between the two simultaneous pressure signals. The subsequent use of a Norwegian Electronic intensity meter, including a proposal for underground work, is shown along with results for tests completed with this piece of equipment. Finally, recommendations are made on how to link up

  7. Lactate threshold by muscle electrical impedance in professional rowers

    Science.gov (United States)

    Jotta, B.; Coutinho, A. B. B.; Pino, A. V.; Souza, M. N.

    2017-04-01

    Lactate threshold (LT) is one of the physiological parameters usually used in rowing sport training prescription because it indicates the transitions from aerobic to anaerobic metabolism. Assessment of LT is classically based on a series of values of blood lactate concentrations obtained during progressive exercise tests and thus has an invasive aspect. The feasibility of noninvasive LT estimative through bioelectrical impedance spectroscopy (BIS) data collected in thigh muscles during rowing ergometer exercise tests was investigated. Nineteen professional rowers, age 19 (mean) ± 4.8 (standard deviation) yr, height 187.3 ± 6.6 cm, body mass 83 ± 7.7 kg, and training experience of 7 ± 4 yr, were evaluated in a rowing ergometer progressive test with paired measures of blood lactate concentration and BIS in thigh muscles. Bioelectrical impedance data were obtained by using a bipolar method of spectroscopy based on the current response to a voltage step. An electrical model was used to interpret BIS data and to derive parameters that were investigated to estimate LT noninvasively. From the serial blood lactate measurements, LT was also determined through Dmax method (LTDmax). The zero crossing of the second derivative of kinetic of the capacitance electrode (Ce), one of the BIS parameters, was used to estimate LT. The agreement between the LT estimates through BIS (LTBIS) and through Dmax method (LTDmax) was evaluated using Bland-Altman plots, leading to a mean difference between the estimates of just 0.07 W and a Pearson correlation coefficient r = 0.85. This result supports the utilization of the proposed method based on BIS parameters for estimating noninvasively the lactate threshold in rowing.

  8. [Endocrine obesity: bioelectric profiles (biotypes) detected in the body composition].

    Science.gov (United States)

    Miggiano, G A D; Petitti, T

    2004-09-01

    136 patients were selected (16 men and 120 women with non-specific menstrual disturbances) with a BMI (Body Mass Index) between 25 and 45 kg/m2, which were diagnosed with "disendocrinia" (GH deficit, hyperadrenocorticism, hypothyroidsm, hyperandrogenism, menstrual cycle disorders). The proposed approach, based on the visualization of the value distribution of the electric measures in different graphics, is able to immediately explain the bioelectric state of the individual's lean-mass. Subjects with hypothyroidism present, along with their overweight, less bio-conducting mass, with an altered fluid intra/extra-cellular distribution. Patients with hyperadrenocorticism show instead an hyperhydratation of the body mass, especially in the extracellular level. Patients with menstrual disorders (amenorrea, polycystic ovary syndrome, anovulatory cycle etc...) present a lean mass reduction (elevated Rs) and an increase of the intra-cellular compartment (elevated-Xc). Patients with hyper-androgenism (and hirsutism) show a characteristic bioelectric "pattern", with low Rs levels and high Xc levels. Subjects with GH deficit (men and women), has a trend of documenting bioelectric measures with lower lean mass and higher fat-mass. Different electric biotypes seem to characterize the body composition in the several endocrine disorders.

  9. Impedance of accelerator components

    International Nuclear Information System (INIS)

    Corlett, J.N.

    1996-05-01

    As demands for high luminosity and low emittance particle beams increase, an understanding of the electromagnetic interaction of these beams with their vacuum chamber environment becomes more important in order to maintain the quality of the beam. This interaction is described in terms of the wake field in time domain, and the beam impedance in frequency domain. These concepts are introduced, and related quantities such as the loss factor are presented. The broadband Q = 1 resonator impedance model is discussed. Perturbation and coaxial wire methods of measurement of real components are reviewed

  10. High temperature impedance spectroscopy of barium stannate ...

    Indian Academy of Sciences (India)

    temperature solid-state reac- tion technique. X-ray diffraction analysis indicated the formation of a single-phase cubic structure with lattice parameter: a = (4·1158 ± 0·0003) .... the equation for the impedance of this circuit. Z = Z − jZ = (. 1/Rg + jωCg. )−1.

  11. Electrical impedance of acupuncture meridians: the relevance of subcutaneous collagenous bands.

    Directory of Open Access Journals (Sweden)

    Andrew C Ahn

    2010-07-01

    Full Text Available The scientific basis for acupuncture meridians is unknown. Past studies have suggested that acupuncture meridians are physiologically characterized by low electrical impedance and anatomically associated with connective tissue planes. We are interested in seeing whether acupuncture meridians are associated with lower electrical impedance and whether ultrasound-derived measures--specifically echogenic collagenous bands--can account for these impedance differences.In 28 healthy subjects, we assessed electrical impedance of skin and underlying subcutaneous connective tissue using a four needle-electrode approach. The impedances were obtained at 10 kHz and 100 kHz frequencies and at three body sites - upper arm (Large Intestine meridian, thigh (Liver, and lower leg (Bladder. Meridian locations were determined by acupuncturists. Ultrasound images were obtained to characterize the anatomical features at each measured site. We found significantly reduced electrical impedance at the Large Intestine meridian compared to adjacent control for both frequencies. No significant decrease in impedance was found at the Liver or Bladder meridian. Greater subcutaneous echogenic densities were significantly associated with reduced impedances in both within-site (meridian vs. adjacent control and between-site (arm vs. thigh vs. lower leg analyses. This relationship remained significant in multivariable analyses which also accounted for gender, needle penetration depth, subcutaneous layer thickness, and other ultrasound-derived measures.Collagenous bands, represented by increased ultrasound echogenicity, are significantly associated with lower electrical impedance and may account for reduced impedances previously reported at acupuncture meridians. This finding may provide important insights into the nature of acupuncture meridians and the relevance of collagen in bioelectrical measurements.

  12. Synthesis of adaptive impedance control for bipedal robot mechanisms

    OpenAIRE

    Petrović Milena; Rodić Aleksandar

    2008-01-01

    The paper describes the impedance algorithm in locomotion of humanoid robot with proposed parameter modulation depending on the gate phase. The analysis shows influence of walking speed and foot elevation on regulator's parameters. Chosen criterion cares for footpath tracking and needed energy for that way of walking. The experiments give recommendation for impedance regulator tuning.

  13. Implantable Impedance Plethysmography

    Directory of Open Access Journals (Sweden)

    Michael Theodor

    2014-08-01

    Full Text Available We demonstrate by theory, as well as by ex vivo and in vivo measurements that impedance plethysmography, applied extravascularly directly on large arteries, is a viable method for monitoring various cardiovascular parameters, such as blood pressure, with high accuracy. The sensor is designed as an implant to monitor cardiac events and arteriosclerotic progression over the long term.

  14. Impedance plethysmography: basic principles.

    Directory of Open Access Journals (Sweden)

    Babu J

    1990-04-01

    Full Text Available Impedance Plethysmography technique has been discussed with explanation of two compartment model and parallel conductor theory for the estimation of peripheral blood flow and stroke volume. Various methods for signal enhancement to facilitate computation of blood flow are briefly described. Source of error in the estimation of peripheral blood flow is identified and the correction has been suggested.

  15. A NOVEL SINGLE IMPEDANCE NETWORK BASED NEUTRAL POINT CLAMPED SEVEN LEVEL THREE PHASE INVETER WITH REDUCED CLAMPING DIODES FOR REGENERATIVE APPLICATIONS

    OpenAIRE

    T. A. Raghavendiran; C.L.Kuppuswamy

    2012-01-01

    A Multilevel Inverter (MLI) can eliminate the need for the step-up transformer and reduce the harmonics produced by the inverter. This paper presents Neutral Point Clamped (NPC) seven level inverter with less number of clamping diodes which is suitable for regenerative loads such as three phase induction motor with regenerative braking. To reduce the stress across the main switches, diodes are clamped anti-parallel to the main switches. In Earlier configurations, the numbers of clamping diode...

  16. Influence of electrode impedance changes on the common-mode rejection ratio in bioimpedance measurements.

    Science.gov (United States)

    Petrova, G I

    1999-11-01

    Bioelectrical impedance in vivo measurements suffer from many potential sources of error due to the patient-instrument interface. The total common-mode rejection ratio (CMRR(T)) was investigated experimentally for three measurement channel circuit versions, including electrode-skin impedance imbalance. The first version was of the 'classical' type. The second one makes use of a differential filter at the input of the instrumentation amplifier. The third circuit was a frequency-converting structure, where the signal was demodulated before being amplified. The differential demodulator was based on synchronous sampling using floating capacitors. The experiments were accomplished with simulated imbalance of the real and imaginary parts of electrode-skin impedances. To reduce unwanted common-mode voltage, a differential accurately balanced current source was used. Considering an application in impedance cardiography, the experiments were carried out at a single frequency of 40 kHz. The results showed the advantage of the circuits using frequency conversion and differential input filter, rendering at least 15 dB higher CMRR(T). The most significant reduction of CMRR(T) resulted from imbalance of the capacitance component of voltage-sensing electrode impedances. The third circuit showed an unexpected behaviour of CMRR(T) improvement with higher imbalance of the electrode-skin impedance resistance component.

  17. Meaning of the negative impedance

    Energy Technology Data Exchange (ETDEWEB)

    Conciauro, G.; Puglisi, M.

    1981-06-01

    It is shown that the negative real part of an input impedance does not mean instability of the related circuit. A negative real part of the input impedance means only that the concerned circuit is active.

  18. Meaning of the negative impedance

    International Nuclear Information System (INIS)

    Conciauro, G.; Puglisi, M.

    1981-06-01

    It is shown that the negative real part of an input impedance does not mean instability of the related circuit. A negative real part of the input impedance means only that the concerned circuit is active

  19. Technical aspects of impedance plethysmography.

    Directory of Open Access Journals (Sweden)

    Bhuta A

    1990-04-01

    Full Text Available This paper describes the basic methods for measurement of body impedance, electrodes and their configuration, and the measuring instrument with its limitations. A microcomputer assisted impedance plethysmograph system, developed at BARC and different lead configurations for impedance plethysmographic investigation are also described. Typical impedance plethysmographic waveforms recorded from a normal subject and measurement of their amplitude and various time intervals are illustrated.

  20. SSC kicker impedances

    International Nuclear Information System (INIS)

    Colton, E.P.; Wang, T.F.

    1985-01-01

    The longitudinal and transverse complex impedances Z/sub l//n and Z/sub t/, respectively, have been calculated for both the SSC injection and abort kickers. The calculations assumed that no attempt was made to shield the beam from the kickers. We took the injection and abort kickers to be as specified. The injection kickers were ferrite with a single-turn design, and the abort kickers were of a ''window-frame design'' with tape wound cores

  1. Gynecologic electrical impedance tomograph

    Science.gov (United States)

    Korjenevsky, A.; Cherepenin, V.; Trokhanova, O.; Tuykin, T.

    2010-04-01

    Electrical impedance tomography extends to the new and new areas of the medical diagnostics: lungs, breast, prostate, etc. The feedback from the doctors who use our breast EIT diagnostic system has induced us to develop the 3D electrical impedance imaging device for diagnostics of the cervix of the uterus - gynecologic impedance tomograph (GIT). The device uses the same measuring approach as the breast imaging system: 2D flat array of the electrodes arranged on the probe with handle is placed against the body. Each of the 32 electrodes of the array is connected in turn to the current source while the rest electrodes acquire the potentials on the surface. The current flows through the electrode of the array and returns through the remote electrode placed on the patient's limb. The voltages are measured relative to another remote electrode. The 3D backprojection along equipotential surfaces is used to reconstruct conductivity distribution up to approximately 1 cm in depth. Small number of electrodes enables us to implement real time imaging with a few frames per sec. rate. The device is under initial testing and evaluation of the imaging capabilities and suitability of usage.

  2. MD 349: Impedance Localization with AC-dipole

    CERN Document Server

    Biancacci, Nicolo; Metral, Elias; Salvant, Benoit; Papotti, Giulia; Persson, Tobias Hakan Bjorn; Tomas Garcia, Rogelio; CERN. Geneva. ATS Department

    2016-01-01

    The purpose of this MD is to measure the distribution of the transverse impedance of the LHC by observing the phase advance variation with intensity between the machine BPMs. Four injected bunches with different intensities are excited with an AC dipole and the turn by turn data is acquired from the BPM system. Through post-processing analysis the phase variation along the machine is depicted and, from this information, first conclusions of the impedance distribution can be drawn.

  3. A flexible electrode array for muscle impedance measurements in the mouse hind limb: A tool to speed research in neuromuscular disease

    Science.gov (United States)

    Li, J.; Rutkove, S. B.

    2013-04-01

    Electrical impedance myography (EIM) is a bioelectrical impedance technique focused on the assessment of neuromuscular diseases using tetrapolar surface arrays. Recently, we have shown that reproducible and sensitive EIM measurements can be made on the gastrocnemius muscle of the mouse hind limb and that these are sensitive to disease alterations. A dedicated array would help speed data acquisition and provide additional sensitivity to disease-induced alterations. A flexible electrode array was developed with electrode sizes of 1mm × 1mm by Parlex, Inc. Tetrapolar electrode sets were arranged both parallel to (longitudinal) and orthogonally to (transverse) the major muscle fiber direction of the gastrocnemius muscle. Measurements were made with a dedicated EIM system. A total of 11 healthy animals and 7 animals with spinal muscular atrophy (a form of motor neuron disease) were evaluated after the fur was completely removed with a depilatory agent from the hind limb. Standard electrophysiologic testing (compound motor action potential amplitude and motor unit number estimation) was also performed. The flexible electrode array demonstrated high repeatability in both the longitudinal and transverse directions in the healthy and diseased animals (with intraclass correlation coefficients of 0.94 and 0.89, respectively, for phase angle measured transversely). In addition, differences between healthy and diseased animals were identifiable. For example, the 50 kHz transverse phase angle was higher in the healthy as compared to the SMA animals (16.8° ± 0.5 vs. 14.3° ± 0.7, respectively) at 21 weeks of age (p = 0.01). Differences in anisotropy were also identifiable. Correlations to several standard neurophysiologic parameters also appeared promising. This novel flexible tetrapolar electrode array can be used on the mouse hind limb and provides multidirectional data that can be used to assess muscle health. This technique has the potential of finding widespread use in

  4. A flexible electrode array for muscle impedance measurements in the mouse hind limb: A tool to speed research in neuromuscular disease

    International Nuclear Information System (INIS)

    Li, J; Rutkove, S B

    2013-01-01

    Electrical impedance myography (EIM) is a bioelectrical impedance technique focused on the assessment of neuromuscular diseases using tetrapolar surface arrays. Recently, we have shown that reproducible and sensitive EIM measurements can be made on the gastrocnemius muscle of the mouse hind limb and that these are sensitive to disease alterations. A dedicated array would help speed data acquisition and provide additional sensitivity to disease-induced alterations. A flexible electrode array was developed with electrode sizes of 1mm × 1mm by Parlex, Inc. Tetrapolar electrode sets were arranged both parallel to (longitudinal) and orthogonally to (transverse) the major muscle fiber direction of the gastrocnemius muscle. Measurements were made with a dedicated EIM system. A total of 11 healthy animals and 7 animals with spinal muscular atrophy (a form of motor neuron disease) were evaluated after the fur was completely removed with a depilatory agent from the hind limb. Standard electrophysiologic testing (compound motor action potential amplitude and motor unit number estimation) was also performed. The flexible electrode array demonstrated high repeatability in both the longitudinal and transverse directions in the healthy and diseased animals (with intraclass correlation coefficients of 0.94 and 0.89, respectively, for phase angle measured transversely). In addition, differences between healthy and diseased animals were identifiable. For example, the 50 kHz transverse phase angle was higher in the healthy as compared to the SMA animals (16.8° ± 0.5 vs. 14.3° ± 0.7, respectively) at 21 weeks of age (p = 0.01). Differences in anisotropy were also identifiable. Correlations to several standard neurophysiologic parameters also appeared promising. This novel flexible tetrapolar electrode array can be used on the mouse hind limb and provides multidirectional data that can be used to assess muscle health. This technique has the potential of finding widespread use in

  5. Impedance spectroscopy study and phase transition in phospho-vanadium mixed oxide LiZnV0.5P0.5O4

    Science.gov (United States)

    Rahal, A.; Megdiche Borchani, S.; Guidara, Kamel; Megdiche, Makram

    2017-08-01

    An X-ray crystallographic study has allowed us to identify a powder of the type LiZnV0.5P0.5O4, which contains 50% of vanadium and 50% of phosphore, inside the binary system LiZnVO4-LiZnPO4. The structure is isotypic with the phenacite like LiZnP04. X-ray diffraction patterns are indexed according to the lattice parameters of the rhombohedral system and the R3 space group. IR spectra show the presence of VO4 and PO4 groups in the network of this material. The experimental results indicate that σ_{AC}(ω) is proportional to ( {ωn } ). The activation energy found from the Arrhenius plot confirms that the conduction processing of the material is not due to simple hopping mechanism. The temperature dependence of frequency exponent n was investigated to understanding the conduction mechanism in LiZnV0.5P0.5O4. The non-overlapping small Polaron tunneling (NSPT) model can explain the temperature dependence of the frequency exponent. A phase transition at T = 623 K has been evidenced by Differential scanning calorimetry (DSC) and subsequently confirmed by the analysis of dielectric and electric properties.

  6. Observations involving broadband impedance modelling

    Energy Technology Data Exchange (ETDEWEB)

    Berg, J.S. [Stanford Linear Accelerator Center, Menlo Park, CA (United States)

    1996-08-01

    Results for single- and multi-bunch instabilities can be significantly affected by the precise model that is used for the broadband impedance. This paper discusses three aspects of broadband impedance modelling. The first is an observation of the effect that a seemingly minor change in an impedance model has on the single-bunch mode coupling threshold. The second is a successful attempt to construct a model for the high-frequency tails of an r.f. cavity. The last is a discussion of requirements for the mathematical form of an impedance which follow from the general properties of impedances. (author)

  7. Impedance Determination from Bench Measurements

    CERN Document Server

    Caspers, Friedhelm

    2000-01-01

    The concept of the coaxial wire technique as a bench method for beam coupling impedance measurements is presented. Starting with the lumped element impedance model formulae are given for impedance evaluation from measured scattering parameters, both for the longitudinal and transverse case and also for the loss-factor. Followed by a section on distributed impedances many hints, precautions and practical aspects for the proper use of the measuring instrument are mentioned. The paper concludes with a brief discussion on special methods in particular for simulation of slow beams, measurements beyond waveguide cutoff and resonator techniques for evaluation of very small impedances.

  8. Adaptive control of grid-connected inverters based on online grid impedance measurements

    Energy Technology Data Exchange (ETDEWEB)

    Cespedes, Mauricio; Sun, Jian [Rensselaer Polytechnic Institute, Troy, NY (United States). Dept. of Electrical, Computer and Systems Engineering

    2012-07-01

    Stability of a grid-connected inverter depends on the ratio of the grid impedance to the inverter impedance. Since the grid impedance changes during normal power system conditions, this paper uses first an impulse response analysis method built into a grid-connected inverter for online grid impedance identification. Secondly, in order to develop simple adaptation rules for the inverter control system, the grid impedance is assumed inductive, and used to derive, analytically, the stability limits of PLL bandwidth and grid voltage feedforward gains. Experimental measurements demonstrate the online grid impedance identification and the inverter adaptive control implemented together within the DSP of a three-phase grid-connected inverter. (orig.)

  9. [Assessment of differential lung function by electrical impedance tomography].

    Science.gov (United States)

    de Lema, J Bruno; Serrano, Ernesto; Feixas, Teresa; Calaf, Núria; Camacho, María Valle; Riu, Pere J; Casan, Pere

    2008-08-01

    To compare unilateral lung function estimated by 2 methods: electrical impedance tomography (EIT) and ventilation-perfusion lung scintigraphy. This prospective clinical study was carried out in the pulmonary function laboratory of a general hospital. Twenty patients diagnosed with lung cancer (17 men and 3 women, ranging in age from 25 to 77 years) who were candidates for lung resection underwent ventilation-perfusion lung scanning breathing a radioactive gas. Differential lung function was estimated based on images taken at 2 intercostal spaces in which ventilation and perfusion were represented by changes in bioelectrical impedance. Each lung's contribution to overall respiratory function was also calculated based on scintigraphy. The right lung contributed a mean (SD) of 54% (9%) of ventilation (range, 32%-71%) according to EIT. Scintigraphy similarly estimated the right lung's contribution to be 52% (10%) of total ventilation (range, 31%-80%) and 50% (9%) of perfusion (range, 37%-71%). The difference between the 2 estimates was not significant (t test), and the correlation coefficients between them were r=0.90 for ventilation and r=0.72 for perfusion (P< .05 in both cases). The analysis of agreement showed that the mean difference between the methods was 1.9% (95% confidence interval [CI], 10.5% to -6.8%) for ventilation and 3.4% (95% CI, 17.1% to -10.3%) for perfusion. EIT is able to estimate differential lung function as accurately as ventilation-perfusion scintigraphy.

  10. Correlation between ultrafiltration rate and phase angle measured by BIA in chronic kidney disease patients on regular hemodialysis

    Science.gov (United States)

    Nasution, B. R.; Lubis, A. R.

    2018-03-01

    Chronic Kidney Disease (CKD) patients with regular hemodialysis have high rates of morbidity and mortality that may be related to the hemodynamic effects of rapid UFR and low PhA value. In this study, we investigated whether high UFR is associated with a low value of PhA thus indirectly affect the risk of morbidity and mortality. UFR and Bioelectrical Impedance Analysis (BIA) examination on 92 subjects were recorded shortly after HD and analyzed by using Pearson correlation test. Multivariate analysis was also conducted to identify several factors that can affect the value of Phase angle. The number of HD regular CKD patients with PhAvalue of PhA. After multivariate analysis, the UFR and the etiology of HD are still significantly affect the value of PhA. UFR optimal value in patients with CKD with regular HD is <10 cc/kg/h.

  11. Compost in plant microbial fuel cell for bioelectricity generation.

    Science.gov (United States)

    Moqsud, M A; Yoshitake, J; Bushra, Q S; Hyodo, M; Omine, K; Strik, David

    2015-02-01

    Recycling of organic waste is an important topic in developing countries as well as developed countries. Compost from organic waste has been used for soil conditioner. In this study, an experiment has been carried out to produce green energy (bioelectricity) by using paddy plant microbial fuel cells (PMFCs) in soil mixed with compost. A total of six buckets filled with the same soil were used with carbon fiber as the electrodes for the test. Rice plants were planted in five of the buckets, with the sixth bucket containing only soil and an external resistance of 100 ohm was used for all cases. It was observed that the cells with rice plants and compost showed higher values of voltage and power density with time. The highest value of voltage showed around 700 mV when a rice plant with 1% compost mixed soil was used, however it was more than 95% less in the case of no rice plant and without compost. Comparing cases with and without compost but with the same number of rice plants, cases with compost depicted higher voltage to as much as 2 times. The power density was also 3 times higher when the compost was used in the paddy PMFCs which indicated the influence of compost on bio-electricity generation. Copyright © 2014 Elsevier Ltd. All rights reserved.

  12. Optically Controlled Oscillators in an Engineered Bioelectric Tissue

    Directory of Open Access Journals (Sweden)

    Harold M. McNamara

    2016-07-01

    Full Text Available Complex electrical dynamics in excitable tissues occur throughout biology, but the roles of individual ion channels can be difficult to determine due to the complex nonlinear interactions in native tissue. Here, we ask whether we can engineer a tissue capable of basic information storage and processing, where all functional components are known and well understood. We develop a cell line with four transgenic components: two to enable collective propagation of electrical waves and two to enable optical perturbation and optical readout of membrane potential. We pattern the cell growth to define simple cellular ring oscillators that run stably for >2  h (∼10^{4}  cycles and that can store data encoded in the direction of electrical circulation. Using patterned optogenetic stimulation, we probe the biophysical attributes of this synthetic excitable tissue in detail, including dispersion relations, curvature-dependent wave front propagation, electrotonic coupling, and boundary effects. We then apply the biophysical characterization to develop an optically reconfigurable bioelectric oscillator. These results demonstrate the feasibility of engineering bioelectric tissues capable of complex information processing with optical input and output.

  13. LIA longitudinal coupling impedance

    International Nuclear Information System (INIS)

    Faltens, A.

    1980-01-01

    The beam generated fields enter into the problems of waveform generation and longitudinal stability. In the former, provision must be made for the longitudinally defocusing forces due to the space charge and the beam loading effects on the accelerating voltage due to the current of a presumably known bunch. In the latter, the concern is for the growth of unintentional perturbations to unacceptably large values through the interaction of the charge and current fluctuations with the rest of the beam and the surrounding structures. These beam generated electric fields may be related to the beam current through a coupling impedance

  14. RF impedance measurement calibration

    International Nuclear Information System (INIS)

    Matthews, P.J.; Song, J.J.

    1993-01-01

    The intent of this note is not to explain all of the available calibration methods in detail. Instead, we will focus on the calibration methods of interest for RF impedance coupling measurements and attempt to explain: (1). The standards and measurements necessary for the various calibration techniques. (2). The advantages and disadvantages of each technique. (3). The mathematical manipulations that need to be applied to the measured standards and devices. (4). An outline of the steps needed for writing a calibration routine that operated from a remote computer. For further details of the various techniques presented in this note, the reader should consult the references

  15. Summary of Human Ankle Mechanical Impedance During Walking.

    Science.gov (United States)

    Lee, Hyunglae; Rouse, Elliott J; Krebs, Hermano Igo

    2016-01-01

    The human ankle joint plays a critical role during walking and understanding the biomechanical factors that govern ankle behavior and provides fundamental insight into normal and pathologically altered gait. Previous researchers have comprehensively studied ankle joint kinetics and kinematics during many biomechanical tasks, including locomotion; however, only recently have researchers been able to quantify how the mechanical impedance of the ankle varies during walking. The mechanical impedance describes the dynamic relationship between the joint position and the joint torque during perturbation, and is often represented in terms of stiffness, damping, and inertia. The purpose of this short communication is to unify the results of the first two studies measuring ankle mechanical impedance in the sagittal plane during walking, where each study investigated differing regions of the gait cycle. Rouse et al. measured ankle impedance from late loading response to terminal stance, where Lee et al. quantified ankle impedance from pre-swing to early loading response. While stiffness component of impedance increases significantly as the stance phase of walking progressed, the change in damping during the gait cycle is much less than the changes observed in stiffness. In addition, both stiffness and damping remained low during the swing phase of walking. Future work will focus on quantifying impedance during the "push off" region of stance phase, as well as measurement of these properties in the coronal plane.

  16. Modeling the Impedance of Nanostructured PV in Simulink/matlab

    Science.gov (United States)

    Houshmand, Mohammad; Zandi, Mohammad. H.; Gorji, Nima E.

    2013-08-01

    Impedance measurement is a common method to study the electrical properties of thin film photovoltaics. For the first time, we use the MATLAB/Simulink environment to extract the complex impedance of the nanostructured heterojunction solar cells. The impedance magnitude, phase and Nyquist plot of the PV are simulated in LTI Viewer and Impedance versus Frequency analysis tools of SimPower GUI block of Simulink. We examined a variety of the equivalent circuits consisting of capacitance, series and shunt resistances representing the solar cell structure. The model uses the parameters with values reported in the literature at room temperature and zero bias. The effect of the additional capacitance and resistances in the equivalent circuits on the impedance components of the cells is considered by Simulink environment.

  17. Electrical impedance tomography.

    Science.gov (United States)

    Costa, Eduardo L V; Lima, Raul Gonzalez; Amato, Marcelo B P

    2009-02-01

    Electrical impedance tomography (EIT) is a noninvasive, radiation-free monitoring tool that allows real-time imaging of ventilation. The purpose of this article is to discuss the fundamentals of EIT and to review the use of EIT in critical care patients. In addition to its established role in describing the distribution of alveolar ventilation, EIT has been shown to be a useful tool to detect lung collapse and monitor lung recruitment, both regionally and on a global basis. EIT has also been used to diagnose with high sensitivity incident pneumothoraces during mechanical ventilation. Additionally, with injection of hypertonic saline as a contrast agent, it is possible to estimate ventilation/perfusion distributions. EIT is cheap, noninvasive and allows continuous monitoring of ventilation. It is gaining acceptance as a valuable monitoring tool for the care of critical patients.

  18. AC impedance diagnosis of a 500 W PEM fuel cell stack . Part I: Stack impedance

    Science.gov (United States)

    Yuan, Xiaozi; Sun, Jian Colin; Blanco, Mauricio; Wang, Haijiang; Zhang, Jiujun; Wilkinson, David P.

    Diagnosis of stack performance is of importance to proton exchange membrane (PEM) fuel cell research. This paper presents the diagnostic testing results of a 500 W Ballard Mark V PEM fuel cell stack with an active area of 280 cm 2 by electrochemical impedance spectroscopy (EIS). The EIS was measured using a combination of a FuelCon test station, a TDI loadbank, and a Solartron 1260 Impedance/Gain-Phase Analyzer operating in the galvanostatic mode. The method described in this work can obtain the impedance spectra of fuel cells with a larger geometric surface area and power, which are normally difficult to measure due to the limitations on commercial load banks operating at high currents. By using this method, the effects of temperature, flow rate, and humidity on the stack impedance spectra were examined. The results of the electrochemical impedance analysis show that with increasing temperature, the charge transfer resistance decreases due to the slow oxygen reduction reaction (ORR) process at low temperature. If the stack is operated at a fixed air flow rate, a low frequency arc appears and grows with increasing current due to the shortage of air. The anode humidification cut-off does not affect the spectra compared to the cut-off for cathode humidification.

  19. Impedance-Source Networks for Electric Power Conversion Part I

    DEFF Research Database (Denmark)

    Siwakoti, Yam P.; Peng, Fang Zheng; Blaabjerg, Frede

    2015-01-01

    is the first of its kind with the aim of providing a “one-stop” information source and a selection guide on impedance-source networks for power conversion for researchers, designers, and application engineers. A comprehensive review of various modeling, control, and modulation techniques for the impedance......Impedance networks cover the entire of electric power conversion from dc (converter, rectifier), ac (inverter), to phase and frequency conversion (ac-ac) in a wide range of applications. Various converter topologies have been reported in the literature to overcome the limitations and problems......-source converters/inverters will be presented in Part II....

  20. Bioelectricity-AQA, one of the first MOOC courses in engineering.

    Science.gov (United States)

    Barr, Roger C

    2014-01-01

    Bioelectricity-AQA was one of the first massively open online courses in engineering, having been given the first time via Coursera starting in September, 2012. This report provides some detail on its background, presentation, enrollment, and lessons learned.