A Full-Body Layered Deformable Model for Automatic Model-Based Gait Recognition

Science.gov (United States)

Lu, Haiping; Plataniotis, Konstantinos N.; Venetsanopoulos, Anastasios N.

2007-12-01

This paper proposes a full-body layered deformable model (LDM) inspired by manually labeled silhouettes for automatic model-based gait recognition from part-level gait dynamics in monocular video sequences. The LDM is defined for the fronto-parallel gait with 22 parameters describing the human body part shapes (widths and lengths) and dynamics (positions and orientations). There are four layers in the LDM and the limbs are deformable. Algorithms for LDM-based human body pose recovery are then developed to estimate the LDM parameters from both manually labeled and automatically extracted silhouettes, where the automatic silhouette extraction is through a coarse-to-fine localization and extraction procedure. The estimated LDM parameters are used for model-based gait recognition by employing the dynamic time warping for matching and adopting the combination scheme in AdaBoost.M2. While the existing model-based gait recognition approaches focus primarily on the lower limbs, the estimated LDM parameters enable us to study full-body model-based gait recognition by utilizing the dynamics of the upper limbs, the shoulders and the head as well. In the experiments, the LDM-based gait recognition is tested on gait sequences with differences in shoe-type, surface, carrying condition and time. The results demonstrate that the recognition performance benefits from not only the lower limb dynamics, but also the dynamics of the upper limbs, the shoulders and the head. In addition, the LDM can serve as an analysis tool for studying factors affecting the gait under various conditions.

Combined brain voxel-based morphometry and diffusion tensor imaging study in idiopathic restless legs syndrome patients.

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Rizzo, G; Manners, D; Vetrugno, R; Tonon, C; Malucelli, E; Plazzi, G; Marconi, S; Pizza, F; Testa, C; Provini, F; Montagna, P; Lodi, R

2012-07-01

  The aim of this study was to evaluate the presence of abnormalities in the brain of patients with restless legs syndrome (RLS) using voxel-based morphometry and diffusion tensor imaging (DTI).   Twenty patients and twenty controls were studied. Voxel-based morphometry analysis was performed using statistical parametric mapping (SPM8) and FSL-VBM software tools. For voxel-wise analysis of DTI, tract-based spatial statistics (TBSS) and SPM8 were used.   Applying an appropriate threshold of probability, no significant results were found either in comparison or in correlation analyses.   Our data argue against clear structural or microstructural abnormalities in the brain of patients with idiopathic RLS, suggesting a prevalent role of functional or metabolic impairment. © 2011 The Author(s) European Journal of Neurology © 2011 EFNS.

Evidence of end-effector based gait machines in gait rehabilitation after CNS lesion.

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Hesse, S; Schattat, N; Mehrholz, J; Werner, C

2013-01-01

A task-specific repetitive approach in gait rehabilitation after CNS lesion is well accepted nowadays. To ease the therapists' and patients' physical effort, the past two decades have seen the introduction of gait machines to intensify the amount of gait practice. Two principles have emerged, an exoskeleton- and an endeffector-based approach. Both systems share the harness and the body weight support. With the end-effector-based devices, the patients' feet are positioned on two foot plates, whose movements simulate stance and swing phase. This article provides an overview on the end-effector based machine's effectiveness regarding the restoration of gait. For the electromechanical gait trainer GT I, a meta analysis identified nine controlled trials (RCT) in stroke subjects (n = 568) and were analyzed to detect differences between end-effector-based locomotion + physiotherapy and physiotherapy alone. Patients practising with the machine effected in a superior gait ability (210 out of 319 patients, 65.8% vs. 96 out of 249 patients, 38.6%, respectively, Z = 2.29, p = 0.020), due to a larger training intensity. Only single RCTs have been reported for other devices and etiologies. The introduction of end-effector based gait machines has opened a new succesful chapter in gait rehabilitation after CNS lesion.

Diffuse Decreased Gray Matter in Patients with Idiopathic Craniocervical Dystonia: a Voxel-Based Morphometry Study

Directory of Open Access Journals (Sweden)

Camila Callegari Piccinin

2015-01-01

Full Text Available Background: Recent studies have addressed the role of structures other than the basal ganglia in the pathophysiology of craniocervical dystonia. Neuroimaging studies have attempted to identify structural abnormalities in craniocervical dystonia but a clear pattern of alteration has not been established. We performed whole brain evaluation using voxel-based morphometry to identify patterns of gray matter changes in craniocervical dystonia.Methods: We compared 27 patients with craniocervical dystonia matched in age and gender to 54 healthy controls. Voxel-based morphometry was used to compare gray matter volumes. We created a two-sample t-test corrected for subjects’ age and we tested with a level of significance of p<0.001 and false discovery rate correction (p<0.05. Results: Voxel-based morphometry demonstrated significant reductions of gray matter using p<0.001 in the cerebellar vermis IV/V, bilaterally in the superior frontal gyrus, precuneus, anterior cingulate and paracingulate, insular cortex, lingual gyrus and calcarine fissure; in the left hemisphere in the supplemementary motor area (SMA, inferior frontal gyrus, inferior parietal gyrus, temporal pole, supramarginal gyrus, rolandic operculum , hippocampus, middle occipital gyrus, cerebellar lobules IV/V, superior and middle temporal gyri; in the right hemisphere, the middle cingulate and precentral gyrus. Our study did not report any significant result using the false discovery rate correction. We also detected correlations between gray matter volume and age, disease duration, duration of botulinum toxin treatment and the Marsden-Fahn dystonia scale scores.Conclusions: We detected large clusters of gray matter changes chiefly in structures primarily involved in sensorimotor integration, motor planning, visuospatial function and emotional processing.

Comparison of the Classifier Oriented Gait Score and the Gait Profile Score based on imitated gait impairments.

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Christian, Josef; Kröll, Josef; Schwameder, Hermann

2017-06-01

Common summary measures of gait quality such as the Gait Profile Score (GPS) are based on the principle of measuring a distance from the mean pattern of a healthy reference group in a gait pattern vector space. The recently introduced Classifier Oriented Gait Score (COGS) is a pathology specific score that measures this distance in a unique direction, which is indicated by a linear classifier. This approach has potentially improved the discriminatory power to detect subtle changes in gait patterns but does not incorporate a profile of interpretable sub-scores like the GPS. The main aims of this study were to extend the COGS by decomposing it into interpretable sub-scores as realized in the GPS and to compare the discriminative power of the GPS and COGS. Two types of gait impairments were imitated to enable a high level of control of the gait patterns. Imitated impairments were realized by restricting knee extension and inducing leg length discrepancy. The results showed increased discriminatory power of the COGS for differentiating diverse levels of impairment. Comparison of the GPS and COGS sub-scores and their ability to indicate changes in specific variables supports the validity of both scores. The COGS is an overall measure of gait quality with increased power to detect subtle changes in gait patterns and might be well suited for tracing the effect of a therapeutic treatment over time. The newly introduced sub-scores improved the interpretability of the COGS, which is helpful for practical applications. Copyright © 2017 Elsevier B.V. All rights reserved.

Finding significantly connected voxels based on histograms of connection strengths

DEFF Research Database (Denmark)

Kasenburg, Niklas; Pedersen, Morten Vester; Darkner, Sune

2016-01-01

We explore a new approach for structural connectivity based segmentations of subcortical brain regions. Connectivity based segmentations are usually based on fibre connections from a seed region to predefined target regions. We present a method for finding significantly connected voxels based...... on the distribution of connection strengths. Paths from seed voxels to all voxels in a target region are obtained from a shortest-path tractography. For each seed voxel we approximate the distribution with a histogram of path scores. We hypothesise that the majority of estimated connections are false-positives...... and that their connection strength is distributed differently from true-positive connections. Therefore, an empirical null-distribution is defined for each target region as the average normalized histogram over all voxels in the seed region. Single histograms are then tested against the corresponding null...

Gray matter abnormalities in Internet addiction: A voxel-based morphometry study

International Nuclear Information System (INIS)

Zhou Yan; Lin Fuchun; Du Yasong; Qin Lingdi; Zhao Zhimin; Xu Jianrong; Lei Hao

2011-01-01

Background: This study aims to investigate brain gray matter density (GMD) changes in adolescents with Internet addiction (IA) using voxel-based morphometry (VBM) analysis on high-resolution T1-weighted structural magnetic resonance images. Methods: Eighteen IA adolescents and 15 age- and gender-matched healthy controls took part in this study. High-resolution T1-weighted magnetic resonance imaging scans were performed on the two groups. VBM analysis was used to compare the GMD between the two groups. Results: Compared with healthy controls, IA adolescents had lower GMD in the left anterior cingulate cortex, left posterior cingulate cortex, left insula, and left lingual gyrus. Conclusions: Our findings suggested that brain structural changes were present in IA adolescents, and this finding may provide a new insight into the pathogenesis of IA.

Gray matter abnormalities in Internet addiction: A voxel-based morphometry study

Energy Technology Data Exchange (ETDEWEB)

Zhou Yan, E-mail: clare1475@hotmail.com [Department of Radiology, RenJi Hospital, Jiao Tong University Medical School, Shanghai 200127 (China); Lin Fuchun, E-mail: fclin@wipm.ac.cn [State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071 (China); Du Yasong, E-mail: yasongdu@yahoo.com.cn [Department of Child and Adolescent Psychiatry Shanghai Mental Health Center, Shanghai Jiao Tong University, Shanghai 200030 (China); Qin Lingdi, E-mail: flyingfool838@hotmail.com [Department of Radiology, RenJi Hospital, Jiao Tong University Medical School, Shanghai 200127 (China); Zhao Zhimin, E-mail: zmzsky@163.com [Department of Child and Adolescent Psychiatry Shanghai Mental Health Center, Shanghai Jiao Tong University, Shanghai 200030 (China); Xu Jianrong, E-mail: xujianr@hotmail.com [Department of Radiology, RenJi Hospital, Jiao Tong University Medical School, Shanghai 200127 (China); Lei Hao, E-mail: leihao@wipm.ac.cn [State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071 (China)

2011-07-15

Background: This study aims to investigate brain gray matter density (GMD) changes in adolescents with Internet addiction (IA) using voxel-based morphometry (VBM) analysis on high-resolution T1-weighted structural magnetic resonance images. Methods: Eighteen IA adolescents and 15 age- and gender-matched healthy controls took part in this study. High-resolution T1-weighted magnetic resonance imaging scans were performed on the two groups. VBM analysis was used to compare the GMD between the two groups. Results: Compared with healthy controls, IA adolescents had lower GMD in the left anterior cingulate cortex, left posterior cingulate cortex, left insula, and left lingual gyrus. Conclusions: Our findings suggested that brain structural changes were present in IA adolescents, and this finding may provide a new insight into the pathogenesis of IA.

Diffusion tensor imaging and voxel based morphometry study in amyotrophic lateral sclerosis: relationships with motor disability

OpenAIRE

Thivard, Lionel; Pradat, Pierre‐François; Lehéricy, Stéphane; Lacomblez, Lucette; Dormont, Didier; Chiras, Jacques; Benali, Habib; Meininger, Vincent

2007-01-01

International audience; The aim of this study was to investigate the extent of cortical and subcortical lesions in amyotrophic lateral sclerosis (ALS) using, in combination, voxel based diffusion tensor imaging (DTI) and voxel based morphometry (VBM). We included 15 patients with definite or probable ALS and 25 healthy volunteers. Patients were assessed using the revised ALS Functional Rating Scale (ALSFRS-R). In patients, reduced fractional anisotropy was found in bilateral corticospinal tra...

Whole-body voxel-based personalized dosimetry: Multiple voxel S-value approach for heterogeneous media with non-uniform activity distributions.

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Lee, Min Sun; Kim, Joong Hyun; Paeng, Jin Chul; Kang, Keon Wook; Jeong, Jae Min; Lee, Dong Soo; Lee, Jae Sung

2017-12-14

Personalized dosimetry with high accuracy is becoming more important because of the growing interests in personalized medicine and targeted radionuclide therapy. Voxel-based dosimetry using dose point kernel or voxel S-value (VSV) convolution is available. However, these approaches do not consider medium heterogeneity. Here, we propose a new method for whole-body voxel-based personalized dosimetry for heterogeneous media with non-uniform activity distributions, which is referred to as the multiple VSV approach. Methods: The multiple numbers (N) of VSVs for media with different densities covering the whole-body density ranges were used instead of using only a single VSV for water. The VSVs were pre-calculated using GATE Monte Carlo simulation; those were convoluted with the time-integrated activity to generate density-specific dose maps. Computed tomography-based segmentation was conducted to generate binary maps for each density region. The final dose map was acquired by the summation of N segmented density-specific dose maps. We tested several sets of VSVs with different densities: N = 1 (single water VSV), 4, 6, 8, 10, and 20. To validate the proposed method, phantom and patient studies were conducted and compared with direct Monte Carlo, which was considered the ground truth. Finally, patient dosimetry (10 subjects) was conducted using the multiple VSV approach and compared with the single VSV and organ-based dosimetry approaches. Errors at the voxel- and organ-levels were reported for eight organs. Results: In the phantom and patient studies, the multiple VSV approach showed significant improvements regarding voxel-level errors, especially for the lung and bone regions. As N increased, voxel-level errors decreased, although some overestimations were observed at lung boundaries. In the case of multiple VSVs ( N = 8), we achieved voxel-level errors of 2.06%. In the dosimetry study, our proposed method showed much improved results compared to the single VSV and

Frontotemporal alterations in pediatric bipolar disorder: results of a voxel-based morphometry study.

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Dickstein, Daniel P; Milham, Michael P; Nugent, Allison C; Drevets, Wayne C; Charney, Dennis S; Pine, Daniel S; Leibenluft, Ellen

2005-07-01

While numerous magnetic resonance imaging (MRI) studies have evaluated adults with bipolar disorder (BPD), few have examined MRI changes in children with BPD. To determine volume alterations in children with BPD using voxel-based morphometry, an automated MRI analysis method with reduced susceptibility to various biases. A priori regions of interest included amygdala, accumbens, hippocampus, dorsolateral prefrontal cortex (DLPFC), and orbitofrontal cortex. Ongoing study of the pathophysiology of pediatric BPD. Intramural National Institute of Mental Health; approved by the institutional review board. Patients Pediatric subjects with BPD (n = 20) with at least 1 manic or hypomanic episode meeting strict DSM-IV criteria for duration and elevated, expansive mood. Controls (n = 20) and their first-degree relatives lacked psychiatric disorders. Groups were matched for age and sex and did not differ in IQ. With a 1.5-T MRI machine, we collected 1.2-mm axial sections (124 per subject) with an axial 3-dimensional spoiled gradient recalled echo in the steady state sequence. Image analysis was by optimized voxel-based morphometry. Subjects with BPD had reduced gray matter volume in the left DLPFC. With a less conservative statistical threshold, additional gray matter reductions were found in the left accumbens and left amygdala. No difference was found in the hippocampus or orbitofrontal cortex. Our results are consistent with data implicating the prefrontal cortex in emotion regulation, a process that is perturbed in BPD. Reductions in amygdala and accumbens volumes are consistent with neuropsychological data on pediatric BPD. Further study is required to determine the relationship between these findings in children and adults with BPD.

The brain and the subjective experience of time. A voxel based symptom-lesion mapping study.

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Trojano, Luigi; Caccavale, Michelina; De Bellis, Francesco; Crisci, Claudio

2017-06-30

The aim of the study was to identify the anatomical bases involved in the subjective experience of time, by means of a voxel based symptom-lesion mapping (VLSM) study on patients with focal brain damage. Thirty-three patients (nineteen with right-hemisphere lesions -RBD, and fourteen with left lesion- LBD) and twenty-eight non-neurological controls (NNC) underwent the semi-structured QUEstionnaire for the Subjective experience of Time (QUEST) requiring retrospective and prospective judgements on self-relevant time intervals. All participants also completed tests to assess general cognitive functioning and two questionnaires to evaluate their emotional state. Both groups of brain-damaged patients achieved significantly different scores from NNC on the time performance, without differences between RBD and LBD. VLSM showed a cluster of voxels located in the right inferior parietal lobule significantly related to errors in the prospective items. The lesion subtraction analysis revealed two different patterns possibly associated with errors in the prospective items (the right inferior parietal cortex, rolandic operculum and posterior middle temporal gyrus) and in the retrospective items (superior middle temporal gyrus, white matter posterior to the insula). Copyright © 2017 Elsevier B.V. All rights reserved.

Technology-Based Feedback and Its Efficacy in Improving Gait Parameters in Patients with Abnormal Gait: A Systematic Review

Directory of Open Access Journals (Sweden)

Gema Chamorro-Moriana

2018-01-01

Full Text Available This systematic review synthesized and analyzed clinical findings related to the effectiveness of innovative technological feedback for tackling functional gait recovery. An electronic search of PUBMED, PEDro, WOS, CINAHL, and DIALNET was conducted from January 2011 to December 2016. The main inclusion criteria were: patients with modified or abnormal gait; application of technology-based feedback to deal with functional recovery of gait; any comparison between different kinds of feedback applied by means of technology, or any comparison between technological and non-technological feedback; and randomized controlled trials. Twenty papers were included. The populations were neurological patients (75%, orthopedic and healthy subjects. All participants were adults, bar one. Four studies used exoskeletons, 6 load platforms and 5 pressure sensors. The breakdown of the type of feedback used was as follows: 60% visual, 40% acoustic and 15% haptic. 55% used terminal feedback versus 65% simultaneous feedback. Prescriptive feedback was used in 60% of cases, while 50% used descriptive feedback. 62.5% and 58.33% of the trials showed a significant effect in improving step length and speed, respectively. Efficacy in improving other gait parameters such as balance or range of movement is observed in more than 75% of the studies with significant outcomes. Conclusion: Treatments based on feedback using innovative technology in patients with abnormal gait are mostly effective in improving gait parameters and therefore useful for the functional recovery of patients. The most frequently highlighted types of feedback were immediate visual feedback followed by terminal and immediate acoustic feedback.

Wearable Device-Based Gait Recognition Using Angle Embedded Gait Dynamic Images and a Convolutional Neural Network.

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Zhao, Yongjia; Zhou, Suiping

2017-02-28

The widespread installation of inertial sensors in smartphones and other wearable devices provides a valuable opportunity to identify people by analyzing their gait patterns, for either cooperative or non-cooperative circumstances. However, it is still a challenging task to reliably extract discriminative features for gait recognition with noisy and complex data sequences collected from casually worn wearable devices like smartphones. To cope with this problem, we propose a novel image-based gait recognition approach using the Convolutional Neural Network (CNN) without the need to manually extract discriminative features. The CNN's input image, which is encoded straightforwardly from the inertial sensor data sequences, is called Angle Embedded Gait Dynamic Image (AE-GDI). AE-GDI is a new two-dimensional representation of gait dynamics, which is invariant to rotation and translation. The performance of the proposed approach in gait authentication and gait labeling is evaluated using two datasets: (1) the McGill University dataset, which is collected under realistic conditions; and (2) the Osaka University dataset with the largest number of subjects. Experimental results show that the proposed approach achieves competitive recognition accuracy over existing approaches and provides an effective parametric solution for identification among a large number of subjects by gait patterns.

Wearable Device-Based Gait Recognition Using Angle Embedded Gait Dynamic Images and a Convolutional Neural Network

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Zhao, Yongjia; Zhou, Suiping

2017-01-01

The widespread installation of inertial sensors in smartphones and other wearable devices provides a valuable opportunity to identify people by analyzing their gait patterns, for either cooperative or non-cooperative circumstances. However, it is still a challenging task to reliably extract discriminative features for gait recognition with noisy and complex data sequences collected from casually worn wearable devices like smartphones. To cope with this problem, we propose a novel image-based gait recognition approach using the Convolutional Neural Network (CNN) without the need to manually extract discriminative features. The CNN’s input image, which is encoded straightforwardly from the inertial sensor data sequences, is called Angle Embedded Gait Dynamic Image (AE-GDI). AE-GDI is a new two-dimensional representation of gait dynamics, which is invariant to rotation and translation. The performance of the proposed approach in gait authentication and gait labeling is evaluated using two datasets: (1) the McGill University dataset, which is collected under realistic conditions; and (2) the Osaka University dataset with the largest number of subjects. Experimental results show that the proposed approach achieves competitive recognition accuracy over existing approaches and provides an effective parametric solution for identification among a large number of subjects by gait patterns. PMID:28264503

A Microsoft Kinect-Based Point-of-Care Gait Assessment Framework for Multiple Sclerosis Patients.

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Gholami, Farnood; Trojan, Daria A; Kovecses, Jozsef; Haddad, Wassim M; Gholami, Behnood

2017-09-01

Gait impairment is a prevalent and important difficulty for patients with multiple sclerosis (MS), a common neurological disorder. An easy to use tool to objectively evaluate gait in MS patients in a clinical setting can assist clinicians to perform an objective assessment. The overall objective of this study is to develop a framework to quantify gait abnormalities in MS patients using the Microsoft Kinect for the Windows sensor; an inexpensive, easy to use, portable camera. Specifically, we aim to evaluate its feasibility for utilization in a clinical setting, assess its reliability, evaluate the validity of gait indices obtained, and evaluate a novel set of gait indices based on the concept of dynamic time warping. In this study, ten ambulatory MS patients, and ten age and sex-matched normal controls were studied at one session in a clinical setting with gait assessment using a Kinect camera. The expanded disability status scale (EDSS) clinical ambulation score was calculated for the MS subjects, and patients completed the Multiple Sclerosis walking scale (MSWS). Based on this study, we established the potential feasibility of using a Microsoft Kinect camera in a clinical setting. Seven out of the eight gait indices obtained using the proposed method were reliable with intraclass correlation coefficients ranging from 0.61 to 0.99. All eight MS gait indices were significantly different from those of the controls (p-values less than 0.05). Finally, seven out of the eight MS gait indices were correlated with the objective and subjective gait measures (Pearson's correlation coefficients greater than 0.40). This study shows that the Kinect camera is an easy to use tool to assess gait in MS patients in a clinical setting.

[Voxel-Based Morphometry in Autism Spectrum Disorder].

Science.gov (United States)

Yamasue, Hidenori

2017-05-01

Autism spectrum disorder shows deficits in social communication and interaction including nonverbal communicative behaviors (e.g., eye contact, gestures, voice prosody, and facial expressions) and restricted and repetitive behaviors as its core symptoms. These core symptoms are emerged as an atypical behavioral development in toddlers with the disorder. Atypical neural development is considered to be a neural underpinning of such behaviorally atypical development. A number of studies using voxel-based morphometry have already been conducted to compare regional brain volumes between individuals with autism spectrum disorder and those with typical development. Furthermore, more than ten papers employing meta-analyses of the comparisons using voxel based morphometry between individuals with autism spectrum disorder and those with typical development have already been published. The current review paper adds some brief discussions about potential factors contributing to the inconsistency observed in the previous findings such as difficulty in controlling the confounding effects of different developmental phases among study participants.

Brain volumes in healthy adults aged 40 years and over: a voxel-based morphometry study.

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Riello, Roberta; Sabattoli, Francesca; Beltramello, Alberto; Bonetti, Matteo; Bono, Giorgio; Falini, Andrea; Magnani, Giuseppe; Minonzio, Giorgio; Piovan, Enrico; Alaimo, Giuseppina; Ettori, Monica; Galluzzi, Samantha; Locatelli, Enrico; Noiszewska, Malgorzata; Testa, Cristina; Frisoni, Giovanni B

2005-08-01

Gender and age effect on brain morphology have been extensively investigated. However, the great variety in methods applied to morphology partly explain the conflicting results of linear patterns of tissue changes and lateral asymmetry in men and women. The aim of the present study was to assess the effect of age, gender and laterality on the volumes of gray matter (GM) and white matter (WM) in a large group of healthy adults by means of voxel-based morphometry. This technique, based on observer-independent algorithms, automatically segments the 3 types of tissue and computes the amount of tissue in each single voxel. Subjects were 229 healthy subjects of 40 years of age or older, who underwent magnetic resonance (MR) for reasons other than cognitive impairment. MR images were reoriented following the AC-PC line and, after removing the voxels below the cerebellum, were processed by Statistical Parametric Mapping (SPM99). GM and WM volumes were normalized for intracranial volume. Women had more fractional GM and WM volumes than men. Age was negatively correlated with both fractional GM and WM, and a gender x age interaction effect was found for WM, men having greater WM loss with advancing age. Pairwise differences between left and right GM were negative (greater GM in right hemisphere) in men, and positive (greater GM in left hemisphere) in women (-0.56+/-4.2 vs 0.99+/-4.8; p=0.019). These results support side-specific accelerated WM loss in men, and may help our better understanding of changes in regional brain structures associated with pathological aging.

Combining voxel-based morphometry and diffusion tensor imaging to detect age-related brain changes.

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Lehmbeck, Jan T; Brassen, Stefanie; Weber-Fahr, Wolfgang; Braus, Dieter F

2006-04-03

The present study combined optimized voxel-based morphometry and diffusion tensor imaging to detect age-related brain changes. We compared grey matter density maps (grey matter voxel-based morphometry) and white matter fractional anisotropy maps (diffusion tensor imaging-voxel-based morphometry) between two groups of 17 younger and 17 older women. Older women exhibited reduced white matter fractional anisotropy as well as decreased grey matter density most prominently in the frontal, limbic, parietal and temporal lobes. A discriminant analysis identified four frontal and limbic grey and white matter areas that separated the two groups most effectively. We conclude that grey matter voxel-based morphometry and diffusion tensor imaging voxel-based morphometry are well suited for the detection of age-related changes and their combination provides high accuracy when detecting the neural correlates of aging.

Voxel-based morphometry and voxel-based diffusion tensor analysis in amyotrophic lateral sclerosis

International Nuclear Information System (INIS)

Chen Zhiye; Ma Lin; Lou Xin; Wang Yan

2010-01-01

Objective: To evaluate gray matter volume, white matter volume and FA value changes in amyatrophic lateral sclerosis (ALS) patients by voxel-based morphometry (VBM) and voxel-based diffusion tensor analysis (VBDTA). Methods: Thirty-nine definite or probable ALS patients diagnosed by El Escorial standard and 39 healthy controls were recruited and underwent conventional MR scans and the neuropsychological evaluation. The 3D FSPGR T 1 WI and DTI data were collected on GE Medical 3.0 T MRI system. The 3DT 1 structural images were normalized, segmented and smoothed, and then VBM analysis was performed. DTI data were acquired from 76 healthy controls, and FA map template was made. FA maps generated from the DTI data of ALS patients and healthy controls were normalized to the FA map template for voxel-based analysis. ANCOVA was applied, controlling with age and total intracranial volume for VBM and age for VBDDTA. A statistical threshold of P<0.01 (uncorrected) and cluster level of more than continuous 20 voxels determined significance. Results: Statistical results showed no significant difference in the global volumes of gray matter and white matter, total intracranial volumes and gray matter fraction between ALS patients and healthy controls, but the white matter fraction of ALS patients (0.29 ± 0.02) was significantly less than that of healthy controls (0.30 ± 0.02) statistically (P=0.003). There was significant reduction of gray matter volumes in bilateral superior frontal gyri and precentral gyri, right middle frontal gyrus, right middle and inferior temporal gyrus, left superior occipital gyrus and cuneus and left insula in ALS patients when compared with healthy controls; and the regional reduction of white matter volumes in ALS patients mainly located in genu of corpus callosum, bilateral medial frontal gyri, paracentral lobule and insula, right superior and middle frontal gyrus and left postcentral gyrus. VBDTA showed decrease in FA values in bilateral

A voxel-based MRI morphometric study of Alzheimer's disease

International Nuclear Information System (INIS)

Hao Jing; Li Kuncheng; Yang Yanhui; Wang Wei; Li Ke; Yan Bin; Shan Baoci

2005-01-01

Objective: To assess the diagnostic value of voxel-based Morphometry (VBM) in studying Alzheimer's disease (AD). Methods: Graymatter density were comprehensive assessed by means of VBM on T 1 -weighted MRI volume sets in 19 patients with AD and 15 healthy subjects of similar age and gender ratio, 15 healthy adults. The data were collected on Siemens 1.5 T Sonata MRI systems and analyzed by SPM 99 to generate gray matter density map. Results: Relative to healthy controls, significant clusters of reduced gray matter density were found to affect medial temporal lobe ( hippocampus) (P<0.001). For hippocampus, reduced gray matter density were 1529 in the right and 1281 in the left with right-sided predominance. Moreover, atrophy of right caudate head and left medial thalamus were showed. We demonstrate global asymmetrical cortical atrophy with sparing of the sensorimotor cortex, occipital lobe and cerebellum. Conclusion: The results from VBM are in perfect agreement with those of earlier neuroimaging, which confirmed its value in demonstrating neuroanatomy of AD. VBM, the simple and automatic approach providing a full-brain assessment of AD morphology, has a good clinical perspective. (authors)

Gait recognition based on integral outline

Science.gov (United States)

Ming, Guan; Fang, Lv

2017-02-01

Biometric identification technology replaces traditional security technology, which has become a trend, and gait recognition also has become a hot spot of research because its feature is difficult to imitate and theft. This paper presents a gait recognition system based on integral outline of human body. The system has three important aspects: the preprocessing of gait image, feature extraction and classification. Finally, using a method of polling to evaluate the performance of the system, and summarizing the problems existing in the gait recognition and the direction of development in the future.

A Corner-Point-Grid-Based Voxelization Method for Complex Geological Structure Model with Folds

Science.gov (United States)

Chen, Qiyu; Mariethoz, Gregoire; Liu, Gang

2017-04-01

3D voxelization is the foundation of geological property modeling, and is also an effective approach to realize the 3D visualization of the heterogeneous attributes in geological structures. The corner-point grid is a representative data model among all voxel models, and is a structured grid type that is widely applied at present. When carrying out subdivision for complex geological structure model with folds, we should fully consider its structural morphology and bedding features to make the generated voxels keep its original morphology. And on the basis of which, they can depict the detailed bedding features and the spatial heterogeneity of the internal attributes. In order to solve the shortage of the existing technologies, this work puts forward a corner-point-grid-based voxelization method for complex geological structure model with folds. We have realized the fast conversion from the 3D geological structure model to the fine voxel model according to the rule of isocline in Ramsay's fold classification. In addition, the voxel model conforms to the spatial features of folds, pinch-out and other complex geological structures, and the voxels of the laminas inside a fold accords with the result of geological sedimentation and tectonic movement. This will provide a carrier and model foundation for the subsequent attribute assignment as well as the quantitative analysis and evaluation based on the spatial voxels. Ultimately, we use examples and the contrastive analysis between the examples and the Ramsay's description of isoclines to discuss the effectiveness and advantages of the method proposed in this work when dealing with the voxelization of 3D geologic structural model with folds based on corner-point grids.

Global and regional associations of smaller cerebral gray and white matter volumes with gait in older people.

Directory of Open Access Journals (Sweden)

Michele L Callisaya

Full Text Available BACKGROUND: Gait impairments increase with advancing age and can lead to falls and loss of independence. Brain atrophy also occurs in older age and may contribute to gait decline. We aimed to investigate global and regional relationships of cerebral gray and white matter volumes with gait speed, and its determinants step length and cadence, in older people. METHODS: In a population-based study, participants aged >60 years without Parkinson's disease or brain infarcts underwent magnetic resonance imaging and gait measurements using a computerized walkway. Linear regression was used to study associations of total gray and white matter volumes with gait, adjusting for each other, age, sex, height and white matter hyperintensity volume. Other covariates considered in analyses included weight and vascular disease history. Voxel-based morphometry was used to study regional relationships of gray and white matter with gait. RESULTS: There were 305 participants, mean age 71.4 (6.9 years, 54% male, mean gait speed 1.16 (0.22 m/s. Smaller total gray matter volume was independently associated with poorer gait speed (p = 0.001 and step length (p<0.001, but not cadence. Smaller volumes of cortical and subcortical gray matter in bilateral regions important for motor control, vision, perception and memory were independently associated with slower gait speed and shorter steps. No global or regional associations were observed between white matter volume and gait independent of gray matter volume, white matter hyperintensity volume and other covariates. CONCLUSION: Smaller gray matter volume in bilaterally distributed brain networks serving motor control was associated with slower gait speed and step length, but not cadence.

A voxel visualization and analysis system based on AutoCAD

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Marschallinger, Robert

1996-05-01

A collection of AutoLISP programs is presented which enable the visualization and analysis of voxel models by AutoCAD rel. 12/rel. 13. The programs serve as an interactive, graphical front end for manipulating the results of three-dimensional modeling software producing block estimation data. ASCII data files describing geometry and attributes per estimation block are imported and stored as a voxel array. Each voxel may contain multiple attributes, therefore different parameters may be incorporated in one voxel array. Voxel classification is implemented on a layer basis providing flexible treatment of voxel classes such as recoloring, peeling, or volumetry. A versatile clipping tool enables slicing voxel arrays according to combinations of three perpendicular clipping planes. The programs feature an up-to-date, graphical user interface for user-friendly operation by non AutoCAD specialists.

Average Gait Differential Image Based Human Recognition

Directory of Open Access Journals (Sweden)

Jinyan Chen

2014-01-01

Full Text Available The difference between adjacent frames of human walking contains useful information for human gait identification. Based on the previous idea a silhouettes difference based human gait recognition method named as average gait differential image (AGDI is proposed in this paper. The AGDI is generated by the accumulation of the silhouettes difference between adjacent frames. The advantage of this method lies in that as a feature image it can preserve both the kinetic and static information of walking. Comparing to gait energy image (GEI, AGDI is more fit to representation the variation of silhouettes during walking. Two-dimensional principal component analysis (2DPCA is used to extract features from the AGDI. Experiments on CASIA dataset show that AGDI has better identification and verification performance than GEI. Comparing to PCA, 2DPCA is a more efficient and less memory storage consumption feature extraction method in gait based recognition.

Class Energy Image Analysis for Video Sensor-Based Gait Recognition: A Review

Directory of Open Access Journals (Sweden)

Zhuowen Lv

2015-01-01

Full Text Available Gait is a unique perceptible biometric feature at larger distances, and the gait representation approach plays a key role in a video sensor-based gait recognition system. Class Energy Image is one of the most important gait representation methods based on appearance, which has received lots of attentions. In this paper, we reviewed the expressions and meanings of various Class Energy Image approaches, and analyzed the information in the Class Energy Images. Furthermore, the effectiveness and robustness of these approaches were compared on the benchmark gait databases. We outlined the research challenges and provided promising future directions for the field. To the best of our knowledge, this is the first review that focuses on Class Energy Image. It can provide a useful reference in the literature of video sensor-based gait representation approach.

New lower-limb gait asymmetry indices based on a depth camera.

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Auvinet, Edouard; Multon, Franck; Meunier, Jean

2015-02-24

Various asymmetry indices have been proposed to compare the spatiotemporal, kinematic and kinetic parameters of lower limbs during the gait cycle. However, these indices rely on gait measurement systems that are costly and generally require manual examination, calibration procedures and the precise placement of sensors/markers on the body of the patient. To overcome these issues, this paper proposes a new asymmetry index, which uses an inexpensive, easy-to-use and markerless depth camera (Microsoft Kinect™) output. This asymmetry index directly uses depth images provided by the Kinect™ without requiring joint localization. It is based on the longitudinal spatial difference between lower-limb movements during the gait cycle. To evaluate the relevance of this index, fifteen healthy subjects were tested on a treadmill walking normally and then via an artificially-induced gait asymmetry with a thick sole placed under one shoe. The gait movement was simultaneously recorded using a Kinect™ placed in front of the subject and a motion capture system. The proposed longitudinal index distinguished asymmetrical gait (p indices based on spatiotemporal gait parameters failed using such Kinect™ skeleton measurements. Moreover, the correlation coefficient between this index measured by Kinect™ and the ground truth of this index measured by motion capture is 0.968. This gait asymmetry index measured with a Kinect™ is low cost, easy to use and is a promising development for clinical gait analysis.

Chord-based versus voxel-based methods of electron transport in the skeletal tissues

International Nuclear Information System (INIS)

Shah, Amish P.; Jokisch, Derek W.; Rajon, Didier A.; Watchman, Christopher J.; Patton, Phillip W.; Bolch, Wesley E.

2005-01-01

Anatomic models needed for internal dose assessment have traditionally been developed using mathematical surface equations to define organ boundaries, shapes, and their positions within the body. Many researchers, however, are now advocating the use of tomographic models created from segmented patient computed tomography (CT) or magnetic resonance (MR) scans. In the skeleton, however, the tissue structures of the bone trabeculae, marrow cavities, and endosteal layer are exceedingly small and of complex shape, and thus do not lend themselves easily to either stylistic representations or in-vivo CT imaging. Historically, the problem of modeling the skeletal tissues has been addressed through the development of chord-based methods of radiation particle transport, as given by studies at the University of Leeds (Leeds, UK) using a 44-year male subject. We have proposed an alternative approach to skeletal dosimetry in which excised sections of marrow-intact cadaver spongiosa are imaged directly via microCT scanning. The cadaver selected for initial investigation of this technique was a 66-year male subject of nominal body mass index (22.7 kg m -2 ). The objectives of the present study were to compare chord-based versus voxel-based methods of skeletal dosimetry using data from the UF 66-year male subject. Good agreement between chord-based and voxel-based transport was noted for marrow irradiation by either bone surface or bone volume sources up to 500-1000 keV (depending upon the skeletal site). In contrast, chord-based models of electron transport yielded consistently lower values of the self-absorbed fraction to marrow tissues than seen under voxel-based transport at energies above 100 keV, a feature directly attributed to the inability of chord-based models to account for nonlinear electron trajectories. Significant differences were also noted in the dosimetry of the endosteal layer (for all source tissues), with chord-based transport predicting a higher fraction of

Morphometric changes of whole brain in patients with alcohol addiction: a voxel-based morphometry study

International Nuclear Information System (INIS)

Li Jinfeng; Chen Zhiye; Ma Lin

2011-01-01

Objective: To evaluate morphometric changes of brain in patients with alcohol addiction by voxel-based morphometry. Methods: Fifteen patients with alcohol addiction and 15 health controls were recruited and underwent fluid attenuated inversion recovery (FLAIR) and 3D fast spoiled gradient echo (FSPGR) T 1 -weighted sequences on a 3.0 T MRI system. 3D FSPGR T 1 structure images were normalized, segmented and smoothed, and then underwent voxel-based morphometry. An ANCOVA was applied with age, body mass index (BMI), and education years as covariates because of exact sex match. A statistical threshold of P 0.05). Conclusions: Regional gray and white matter atrophy can be the initial changes in patients with alcohol addiction and the frontal region is a relative specific damaged brain region. VBM has a potential value for the detection of subtle brain atrophy in patients with alcohol addiction. (authors)

Sensitivity study of voxel-based PET image comparison to image registration algorithms

Energy Technology Data Exchange (ETDEWEB)

Yip, Stephen, E-mail: syip@lroc.harvard.edu; Chen, Aileen B.; Berbeco, Ross [Department of Radiation Oncology, Brigham and Women’s Hospital, Dana-Farber Cancer Institute and Harvard Medical School, Boston, Massachusetts 02115 (United States); Aerts, Hugo J. W. L. [Department of Radiation Oncology, Brigham and Women’s Hospital, Dana-Farber Cancer Institute and Harvard Medical School, Boston, Massachusetts 02115 and Department of Radiology, Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts 02115 (United States)

2014-11-01

Purpose: Accurate deformable registration is essential for voxel-based comparison of sequential positron emission tomography (PET) images for proper adaptation of treatment plan and treatment response assessment. The comparison may be sensitive to the method of deformable registration as the optimal algorithm is unknown. This study investigated the impact of registration algorithm choice on therapy response evaluation. Methods: Sixteen patients with 20 lung tumors underwent a pre- and post-treatment computed tomography (CT) and 4D FDG-PET scans before and after chemoradiotherapy. All CT images were coregistered using a rigid and ten deformable registration algorithms. The resulting transformations were then applied to the respective PET images. Moreover, the tumor region defined by a physician on the registered PET images was classified into progressor, stable-disease, and responder subvolumes. Particularly, voxels with standardized uptake value (SUV) decreases >30% were classified as responder, while voxels with SUV increases >30% were progressor. All other voxels were considered stable-disease. The agreement of the subvolumes resulting from difference registration algorithms was assessed by Dice similarity index (DSI). Coefficient of variation (CV) was computed to assess variability of DSI between individual tumors. Root mean square difference (RMS{sub rigid}) of the rigidly registered CT images was used to measure the degree of tumor deformation. RMS{sub rigid} and DSI were correlated by Spearman correlation coefficient (R) to investigate the effect of tumor deformation on DSI. Results: Median DSI{sub rigid} was found to be 72%, 66%, and 80%, for progressor, stable-disease, and responder, respectively. Median DSI{sub deformable} was 63%–84%, 65%–81%, and 82%–89%. Variability of DSI was substantial and similar for both rigid and deformable algorithms with CV > 10% for all subvolumes. Tumor deformation had moderate to significant impact on DSI for progressor

New Lower-Limb Gait Asymmetry Indices Based on a Depth Camera

Directory of Open Access Journals (Sweden)

Edouard Auvinet

2015-02-01

Full Text Available Background: Various asymmetry indices have been proposed to compare the spatiotemporal, kinematic and kinetic parameters of lower limbs during the gait cycle. However, these indices rely on gait measurement systems that are costly and generally require manual examination, calibration procedures and the precise placement of sensors/markers on the body of the patient. Methods: To overcome these issues, this paper proposes a new asymmetry index, which uses an inexpensive, easy-to-use and markerless depth camera (Microsoft Kinect™ output. This asymmetry index directly uses depth images provided by the Kinect™ without requiring joint localization. It is based on the longitudinal spatial difference between lower-limb movements during the gait cycle. To evaluate the relevance of this index, fifteen healthy subjects were tested on a treadmill walking normally and then via an artificially-induced gait asymmetry with a thick sole placed under one shoe. The gait movement was simultaneously recorded using a Kinect™ placed in front of the subject and a motion capture system. Results: The proposed longitudinal index distinguished asymmetrical gait (p < 0.001, while other symmetry indices based on spatiotemporal gait parameters failed using such Kinect™ skeleton measurements. Moreover, the correlation coefficient between this index measured by Kinect™ and the ground truth of this index measured by motion capture is 0.968. Conclusion: This gait asymmetry index measured with a Kinect™ is low cost, easy to use and is a promising development for clinical gait analysis.

Empirical Bayesian estimation in graphical analysis: a voxel-based approach for the determination of the volume of distribution in PET studies

Energy Technology Data Exchange (ETDEWEB)

Zanderigo, Francesca [Department of Molecular Imaging and Neuropathology, New York State Psychiatric Institute, New York, NY (United States)], E-mail: francesca.zanderigo@gmail.com; Ogden, R. Todd [Department of Molecular Imaging and Neuropathology, New York State Psychiatric Institute, New York, NY (United States); Department of Psychiatry, College of Physicians and Surgeons, Columbia University, New York, NY (United States); Department of Biostatistics, Mailman School of Public Health, Columbia University, New York, NY (United States); Bertoldo, Alessandra; Cobelli, Claudio [Department of Information Engineering, University of Padova, Padova (Italy); Mann, J. John; Parsey, Ramin V. [Department of Molecular Imaging and Neuropathology, New York State Psychiatric Institute, New York, NY (United States); Department of Psychiatry, College of Physicians and Surgeons, Columbia University, New York, NY (United States)

2010-05-15

Introduction: Total volume of distribution (V{sub T}) determined by graphical analysis (GA) of PET data suffers from a noise-dependent bias. Likelihood estimation in GA (LEGA) eliminates this bias at the region of interest (ROI) level, but at voxel noise levels, the variance of estimators is high, yielding noisy images. We hypothesized that incorporating LEGA V{sub T} estimation in a Bayesian framework would shrink estimators towards prior means, reducing variability and producing meaningful and useful voxel images. Methods: Empirical Bayesian estimation in GA (EBEGA) determines prior distributions using a two-step k-means clustering of voxel activity. Results obtained on eight [{sup 11}C]-DASB studies are compared with estimators computed by ROI-based LEGA. Results: EBEGA reproduces the results obtained by ROI LEGA while providing low-variability V{sub T} images. Correlation coefficients between average EBEGA V{sub T} and corresponding ROI LEGA V{sub T} range from 0.963 to 0.994. Conclusions: EBEGA is a fully automatic and general approach that can be applied to voxel-level V{sub T} image creation and to any modeling strategy to reduce voxel-level estimation variability without prefiltering of the PET data.

Two-dimensional PCA-based human gait identification

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Chen, Jinyan; Wu, Rongteng

2012-11-01

It is very necessary to recognize person through visual surveillance automatically for public security reason. Human gait based identification focus on recognizing human by his walking video automatically using computer vision and image processing approaches. As a potential biometric measure, human gait identification has attracted more and more researchers. Current human gait identification methods can be divided into two categories: model-based methods and motion-based methods. In this paper a two-Dimensional Principal Component Analysis and temporal-space analysis based human gait identification method is proposed. Using background estimation and image subtraction we can get a binary images sequence from the surveillance video. By comparing the difference of two adjacent images in the gait images sequence, we can get a difference binary images sequence. Every binary difference image indicates the body moving mode during a person walking. We use the following steps to extract the temporal-space features from the difference binary images sequence: Projecting one difference image to Y axis or X axis we can get two vectors. Project every difference image in the difference binary images sequence to Y axis or X axis difference binary images sequence we can get two matrixes. These two matrixes indicate the styles of one walking. Then Two-Dimensional Principal Component Analysis(2DPCA) is used to transform these two matrixes to two vectors while at the same time keep the maximum separability. Finally the similarity of two human gait images is calculated by the Euclidean distance of the two vectors. The performance of our methods is illustrated using the CASIA Gait Database.

Prevalence and Burden of Gait Disorders in Elderly Men and Women Aged 60–97 Years: A Population-Based Study

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Mahlknecht, Philipp; Kiechl, Stefan; Bloem, Bastiaan R.; Willeit, Johann; Scherfler, Christoph; Gasperi, Arno; Rungger, Gregorio; Poewe, Werner; Seppi, Klaus

2013-01-01

Background Although gait disorders are common in the elderly, the prevalence and overall burden of these disorders in the general community is not well defined. Methods In a cross-sectional investigation of the population-based Bruneck Study cohort, 488 community-residing elderly aged 60–97 years underwent a thorough neurological assessment including a standardized gait evaluation. Gait disorders were classified according to an accepted scheme and their associations to falls, neuropsychological measures, and quality of life were explored. Results Overall, 32.2% (95% confidence interval [CI] 28.2%–36.4%) of participants presented with impaired gait. Prevalence increased with age (pgait. A total of 24.0% (95%CI 20.4%–28.0%) manifested neurological gait disorders, 17.4% (14.3%–21.0%) non-neurological gait problems, and 9.2% (6.9%–12.1%) a combination of both. While there was no association of neurological gait disorders with gender, non-neurological gait disorders were more frequent in women (p = 0.012). Within the group of neurological gait disorders 69.2% (95%CI 60.3%–76.9%) had a single distinct entity and 30.8% (23.1%–39.7%) had multiple neurological causes for gait impairment. Gait disorders had a significant negative impact on quantitative gait measures, but only neurological gait disorders were associated with recurrent falls (odds ratio 3.3; 95%CI 1.4–7.5; p = 0.005 for single and 7.1; 2.7–18.7; pgait disorders). Finally, we detected a significant association of gait disorders, in particular neurological gait disorders, with depressed mood, cognitive dysfunction, and compromised quality of life. Conclusions Gait disorders are common in the general elderly population and are associated with reduced mobility. Neurological gait disorders in particular are associated with recurrent falls, lower cognitive function, depressed mood, and diminished quality of life. PMID:23894511

Intra-voxel heterogeneity influences the dose prescription for dose-painting with radiotherapy: a modelling study

NARCIS (Netherlands)

Petit, S.F.; Dekker, A.L.A.J.; Seigneuric, R.; Murrer, L.H.P.; Riel, van N.A.W.; Nordsmark, M.; Overgaard, J.; Lambin, Ph.; Wouters, B.G.

2009-01-01

The purpose of this study was to increase the potential of dose redistribution by incorporating estimates of oxygen heterogeneity within imaging voxels for optimal dose determination. Cellular oxygen tension (pO2) distributions were estimated for imaging-size-based voxels by solving oxygen

Clinical usefulness of augmented reality using infrared camera based real-time feedback on gait function in cerebral palsy: a case study.

Science.gov (United States)

Lee, Byoung-Hee

2016-04-01

[Purpose] This study investigated the effects of real-time feedback using infrared camera recognition technology-based augmented reality in gait training for children with cerebral palsy. [Subjects] Two subjects with cerebral palsy were recruited. [Methods] In this study, augmented reality based real-time feedback training was conducted for the subjects in two 30-minute sessions per week for four weeks. Spatiotemporal gait parameters were used to measure the effect of augmented reality-based real-time feedback training. [Results] Velocity, cadence, bilateral step and stride length, and functional ambulation improved after the intervention in both cases. [Conclusion] Although additional follow-up studies of the augmented reality based real-time feedback training are required, the results of this study demonstrate that it improved the gait ability of two children with cerebral palsy. These findings suggest a variety of applications of conservative therapeutic methods which require future clinical trials.

Gait Analysis Study of Runner Using Force Plate

Directory of Open Access Journals (Sweden)

Flaviana Catherine

2017-02-01

Full Text Available Humans do regular physical activities such as running. Gait is forward  propulsion of the human body using lower extremities as a thrust. Humans gait pattern is characterized by their limbs movement in terms of velocity, ground reaction force, work, kinetic energy and potential energy cycle . Human gait analysis is used to assess, to plan, and to deliver the treatment for individuals based on the conditions that affect their ability to move. Gait analysis is commonly used in running sport to improve the efficiency of athletes in running and to identify problems related to their posture or movement. The aim of this research is to do running gait analysis study of human, using force plate which equipped by track board. The benefit of this study is to provide information, ideas and new perspectives about running and its prevention over an injury. The main method that will be discussed in this study is system design of gait analysis with specific setting, hardware and software, in order to acquire data(s.

Bipedal gait model for precise gait recognition and optimal triggering in foot drop stimulator: a proof of concept.

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Shaikh, Muhammad Faraz; Salcic, Zoran; Wang, Kevin I-Kai; Hu, Aiguo Patrick

2018-03-10

Electrical stimulators are often prescribed to correct foot drop walking. However, commercial foot drop stimulators trigger inappropriately under certain non-gait scenarios. Past researches addressed this limitation by defining stimulation control based on automaton of a gait cycle executed by foot drop of affected limb/foot only. Since gait is a collaborative activity of both feet, this research highlights the role of normal foot for robust gait detection and stimulation triggering. A novel bipedal gait model is proposed where gait cycle is realized as an automaton based on concurrent gait sub-phases (states) from each foot. The input for state transition is fused information from feet-worn pressure and inertial sensors. Thereafter, a bipedal gait model-based stimulation control algorithm is developed. As a feasibility study, bipedal gait model and stimulation control are evaluated in real-time simulation manner on normal and simulated foot drop gait measurements from 16 able-bodied participants with three speed variations, under inappropriate triggering scenarios and with foot drop rehabilitation exercises. Also, the stimulation control employed in commercial foot drop stimulators and single foot gait-based foot drop stimulators are compared alongside. Gait detection accuracy (98.9%) and precise triggering under all investigations prove bipedal gait model reliability. This infers that gait detection leveraging bipedal periodicity is a promising strategy to rectify prevalent stimulation triggering deficiencies in commercial foot drop stimulators. Graphical abstract Bipedal information-based gait recognition and stimulation triggering.

Anatomical specificity of vascular endothelial growth factor expression in glioblastomas: a voxel-based mapping analysis

Energy Technology Data Exchange (ETDEWEB)

Fan, Xing [Capital Medical University, Department of Neurosurgery, Beijing Tiantan Hospital, Beijing (China); Wang, Yinyan [Capital Medical University, Department of Neurosurgery, Beijing Tiantan Hospital, Beijing (China); Capital Medical University, Department of Neuropathology, Beijing Neurosurgical Institute, Beijing (China); Wang, Kai; Ma, Jun; Li, Shaowu [Capital Medical University, Department of Neuroradiology, Beijing Tiantan Hospital, Beijing (China); Liu, Shuai [Chinese Academy of Medical Sciences and Peking Union Medical College, Departments of Neurosurgery, Peking Union Medical College Hospital, Beijing (China); Liu, Yong [Chinese Academy of Sciences, Brainnetome Center, Institute of Automation, Beijing (China); Jiang, Tao [Capital Medical University, Department of Neurosurgery, Beijing Tiantan Hospital, Beijing (China); Beijing Academy of Critical Illness in Brain, Department of Clinical Oncology, Beijing (China)

2016-01-15

The expression of vascular endothelial growth factor (VEGF) is a common genetic alteration in malignant gliomas and contributes to the angiogenesis of tumors. This study aimed to investigate the anatomical specificity of VEGF expression levels in glioblastomas using voxel-based neuroimaging analysis. Clinical information, MR scans, and immunohistochemistry stains of 209 patients with glioblastomas were reviewed. All tumor lesions were segmented manually and subsequently registered to standard brain space. Voxel-based regression analysis was performed to correlate the brain regions of tumor involvement with the level of VEGF expression. Brain regions identified as significantly associated with high or low VEGF expression were preserved following permutation correction. High VEGF expression was detected in 123 (58.9 %) of the 209 patients. Voxel-based statistical analysis demonstrated that high VEGF expression was more likely in tumors located in the left frontal lobe and the right caudate and low VEGF expression was more likely in tumors that occurred in the posterior region of the right lateral ventricle. Voxel-based neuroimaging analysis revealed the anatomic specificity of VEGF expression in glioblastoma, which may further our understanding of genetic heterogeneity during tumor origination. This finding provides primary theoretical support for potential future application of customized antiangiogenic therapy. (orig.)

Anatomical specificity of vascular endothelial growth factor expression in glioblastomas: a voxel-based mapping analysis

International Nuclear Information System (INIS)

Fan, Xing; Wang, Yinyan; Wang, Kai; Ma, Jun; Li, Shaowu; Liu, Shuai; Liu, Yong; Jiang, Tao

2016-01-01

The expression of vascular endothelial growth factor (VEGF) is a common genetic alteration in malignant gliomas and contributes to the angiogenesis of tumors. This study aimed to investigate the anatomical specificity of VEGF expression levels in glioblastomas using voxel-based neuroimaging analysis. Clinical information, MR scans, and immunohistochemistry stains of 209 patients with glioblastomas were reviewed. All tumor lesions were segmented manually and subsequently registered to standard brain space. Voxel-based regression analysis was performed to correlate the brain regions of tumor involvement with the level of VEGF expression. Brain regions identified as significantly associated with high or low VEGF expression were preserved following permutation correction. High VEGF expression was detected in 123 (58.9 %) of the 209 patients. Voxel-based statistical analysis demonstrated that high VEGF expression was more likely in tumors located in the left frontal lobe and the right caudate and low VEGF expression was more likely in tumors that occurred in the posterior region of the right lateral ventricle. Voxel-based neuroimaging analysis revealed the anatomic specificity of VEGF expression in glioblastoma, which may further our understanding of genetic heterogeneity during tumor origination. This finding provides primary theoretical support for potential future application of customized antiangiogenic therapy. (orig.)

Gait Recognition Based on Outermost Contour

Directory of Open Access Journals (Sweden)

Lili Liu

2011-10-01

Full Text Available Gait recognition aims to identify people by the way they walk. In this paper, a simple but e ective gait recognition method based on Outermost Contour is proposed. For each gait image sequence, an adaptive silhouette extraction algorithm is firstly used to segment the frames of the sequence and a series of postprocessing is applied to obtain the normalized silhouette images with less noise. Then a novel feature extraction method based on Outermost Contour is performed. Principal Component Analysis (PCA is adopted to reduce the dimensionality of the distance signals derived from the Outermost Contours of silhouette images. Then Multiple Discriminant Analysis (MDA is used to optimize the separability of gait features belonging to di erent classes. Nearest Neighbor (NN classifier and Nearest Neighbor classifier with respect to class Exemplars (ENN are used to classify the final feature vectors produced by MDA. In order to verify the e ectiveness and robustness of our feature extraction algorithm, we also use two other classifiers: Backpropagation Neural Network (BPNN and Support Vector Machine (SVM for recognition. Experimental results on a gait database of 100 people show that the accuracy of using MDA, BPNN and SVM can achieve 97.67%, 94.33% and 94.67%, respectively.

TU-F-CAMPUS-J-04: Impact of Voxel Anisotropy On Statistic Texture Features of Oncologic PET: A Simulation Study

International Nuclear Information System (INIS)

Yang, F; Byrd, D; Bowen, S; Kinahan, P; Sandison, G

2015-01-01

Purpose: Texture metrics extracted from oncologic PET have been investigated with respect to their usefulness as definitive indicants for prognosis in a variety of cancer. Metric calculation is often based on cubic voxels. Most commonly used PET scanners, however, produce rectangular voxels, which may change texture metrics. The objective of this study was to examine the variability of PET texture feature metrics resulting from voxel anisotropy. Methods: Sinograms of NEMA NU-2 phantom for 18F-FDG were simulated using the ASIM simulation tool. The obtained projection data was reconstructed (3D-OSEM) on grids of cubic and rectangular voxels, producing PET images of resolution of 2.73x2.73x3.27mm3 and 3.27x3.27x3.27mm3, respectively. An interpolated dataset obtained from resampling the rectangular voxel data for isotropic voxel dimension (3.27mm) was also considered. For each image dataset, 28 texture parameters based on grey-level co-occurrence matrices (GLCOM), intensity histograms (GLIH), neighborhood difference matrices (GLNDM), and zone size matrices (GLZSM) were evaluated within lesions of diameter of 33, 28, 22, and 17mm. Results: In reference to the isotopic image data, texture features appearing on the rectangular voxel data varied with a range of -34-10% for GLCOM based, -31-39% for GLIH based, -80 -161% for GLNDM based, and −6–45% for GLZSM based while varied with a range of -35-23% for GLCOM based, -27-35% for GLIH based, -65-86% for GLNDM based, and -22 -18% for GLZSM based for the interpolated image data. For the anisotropic data, GLNDM-cplx exhibited the largest extent of variation (161%) while GLZSM-zp showed the least (<1%). As to the interpolated data, GLNDM-busy varied the most (86%) while GLIH-engy varied the least (<1%). Conclusion: Variability of texture appearance on oncologic PET with respect to voxel representation is substantial and feature-dependent. It necessitates consideration of standardized voxel representation for inter

A biofeedback cycling training to improve locomotion: a case series study based on gait pattern classification of 153 chronic stroke patients

Science.gov (United States)

2011-01-01

Background The restoration of walking ability is the main goal of post-stroke lower limb rehabilitation and different studies suggest that pedaling may have a positive effect on locomotion. The aim of this study was to explore the feasibility of a biofeedback pedaling treatment and its effects on cycling and walking ability in chronic stroke patients. A case series study was designed and participants were recruited based on a gait pattern classification of a population of 153 chronic stroke patients. Methods In order to optimize participants selection, a k-means cluster analysis was performed to subgroup homogenous gait patterns in terms of gait speed and symmetry. The training consisted of a 2-week treatment of 6 sessions. A visual biofeedback helped the subjects in maintaining a symmetrical contribution of the two legs during pedaling. Participants were assessed before, after training and at follow-up visits (one week after treatment). Outcome measures were the unbalance during a pedaling test, and the temporal, spatial, and symmetry parameters during gait analysis. Results and discussion Three clusters, mainly differing in terms of gait speed, were identified and participants, representative of each cluster, were selected. An intra-subject statistical analysis (ANOVA) showed that all patients significantly decreased the pedaling unbalance after treatment and maintained significant improvements with respect to baseline at follow-up. The 2-week treatment induced some modifications in the gait pattern of two patients: one, the most impaired, significantly improved mean velocity and increased gait symmetry; the other one reduced significantly the over-compensation of the healthy limb. No benefits were produced in the gait of the last subject who maintained her slow but almost symmetrical pattern. Thus, this study might suggest that the treatment can be beneficial for patients having a very asymmetrical and inefficient gait and for those that overuse the healthy leg

A biofeedback cycling training to improve locomotion: a case series study based on gait pattern classification of 153 chronic stroke patients

Directory of Open Access Journals (Sweden)

Molteni Franco

2011-08-01

Full Text Available Abstract Background The restoration of walking ability is the main goal of post-stroke lower limb rehabilitation and different studies suggest that pedaling may have a positive effect on locomotion. The aim of this study was to explore the feasibility of a biofeedback pedaling treatment and its effects on cycling and walking ability in chronic stroke patients. A case series study was designed and participants were recruited based on a gait pattern classification of a population of 153 chronic stroke patients. Methods In order to optimize participants selection, a k-means cluster analysis was performed to subgroup homogenous gait patterns in terms of gait speed and symmetry. The training consisted of a 2-week treatment of 6 sessions. A visual biofeedback helped the subjects in maintaining a symmetrical contribution of the two legs during pedaling. Participants were assessed before, after training and at follow-up visits (one week after treatment. Outcome measures were the unbalance during a pedaling test, and the temporal, spatial, and symmetry parameters during gait analysis. Results and discussion Three clusters, mainly differing in terms of gait speed, were identified and participants, representative of each cluster, were selected. An intra-subject statistical analysis (ANOVA showed that all patients significantly decreased the pedaling unbalance after treatment and maintained significant improvements with respect to baseline at follow-up. The 2-week treatment induced some modifications in the gait pattern of two patients: one, the most impaired, significantly improved mean velocity and increased gait symmetry; the other one reduced significantly the over-compensation of the healthy limb. No benefits were produced in the gait of the last subject who maintained her slow but almost symmetrical pattern. Thus, this study might suggest that the treatment can be beneficial for patients having a very asymmetrical and inefficient gait and for those

Does dance-based therapy increase gait speed in older adults with chronic lower extremity pain: a feasibility study.

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Krampe, Jean; Wagner, Joanne M; Hawthorne, Kelly; Sanazaro, Deborah; Wong-Anuchit, Choochart; Budhathoki, Chakra; Lorenz, Rebecca A; Raaf, Soren

2014-01-01

A decreased gait speed in older adults can lead to dependency when the individuals are no longer able to participate in activities or do things for themselves. Thirty-seven senior apartment residents (31 females; Mean age=80.6 years; SD=8.9) with lower extremity pain/stiffness participated in a feasibility and preliminary efficacy study of 12 weeks (24 sessions). Healthy-Steps dance therapy compared to a wait-list control group. Small improvements in gait speed ([ES]=0.33) were noted for participants completing 19-24 dance sessions. Improvements in gait speed measured by a 10 Meter Walk Test (0.0517 m/s) exceeded 0.05 m/s, a value deemed to be meaningful in community dwelling older adults. These feasibility study findings support the need for additional research using dance-based therapy for older adults with lower extremity pain. Copyright © 2014 Elsevier Inc. All rights reserved.

Effect of 6-month community-based exercise interventions on gait and functional fitness of an older population: a quasi-experimental study.

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Ramalho, Fátima; Santos-Rocha, Rita; Branco, Marco; Moniz-Pereira, Vera; André, Helô-Isa; Veloso, António P; Carnide, Filomena

2018-01-01

Gait ability in older adults has been associated with independent living, increased survival rates, fall prevention, and quality of life. There are inconsistent findings regarding the effects of exercise interventions in the maintenance of gait parameters. The aim of the study was to analyze the effects of a community-based periodized exercise intervention on the improvement of gait parameters and functional fitness in an older adult group compared with a non-periodized program. A quasi-experimental study with follow-up was performed in a periodized exercise group (N=15) and in a non-periodized exercise group (N=13). The primary outcomes were plantar pressure gait parameters, and the secondary outcomes were physical activity, aerobic endurance, lower limb strength, agility, and balance. These variables were recorded at baseline and after 6 months of intervention. Both programs were tailored to older adults' functional fitness level and proved to be effective in reducing the age-related decline regarding functional fitness and gait parameters. Gait parameters were sensitive to both the exercise interventions. These exercise protocols can be used by exercise professionals in prescribing community exercise programs, as well as by health professionals in promoting active aging.

Model Predictive Control-based gait pattern generation for wearable exoskeletons.

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Wang, Letian; van Asseldonk, Edwin H F; van der Kooij, Herman

2011-01-01

This paper introduces a new method for controlling wearable exoskeletons that do not need predefined joint trajectories. Instead, it only needs basic gait descriptors such as step length, swing duration, and walking speed. End point Model Predictive Control (MPC) is used to generate the online joint trajectories based on these gait parameters. Real-time ability and control performance of the method during the swing phase of gait cycle is studied in this paper. Experiments are performed by helping a human subject swing his leg with different patterns in the LOPES gait trainer. Results show that the method is able to assist subjects to make steps with different step length and step duration without predefined joint trajectories and is fast enough for real-time implementation. Future study of the method will focus on controlling the exoskeletons in the entire gait cycle. © 2011 IEEE

The impact of sample size on the reproducibility of voxel-based lesion-deficit mappings.

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Lorca-Puls, Diego L; Gajardo-Vidal, Andrea; White, Jitrachote; Seghier, Mohamed L; Leff, Alexander P; Green, David W; Crinion, Jenny T; Ludersdorfer, Philipp; Hope, Thomas M H; Bowman, Howard; Price, Cathy J

2018-07-01

This study investigated how sample size affects the reproducibility of findings from univariate voxel-based lesion-deficit analyses (e.g., voxel-based lesion-symptom mapping and voxel-based morphometry). Our effect of interest was the strength of the mapping between brain damage and speech articulation difficulties, as measured in terms of the proportion of variance explained. First, we identified a region of interest by searching on a voxel-by-voxel basis for brain areas where greater lesion load was associated with poorer speech articulation using a large sample of 360 right-handed English-speaking stroke survivors. We then randomly drew thousands of bootstrap samples from this data set that included either 30, 60, 90, 120, 180, or 360 patients. For each resample, we recorded effect size estimates and p values after conducting exactly the same lesion-deficit analysis within the previously identified region of interest and holding all procedures constant. The results show (1) how often small effect sizes in a heterogeneous population fail to be detected; (2) how effect size and its statistical significance varies with sample size; (3) how low-powered studies (due to small sample sizes) can greatly over-estimate as well as under-estimate effect sizes; and (4) how large sample sizes (N ≥ 90) can yield highly significant p values even when effect sizes are so small that they become trivial in practical terms. The implications of these findings for interpreting the results from univariate voxel-based lesion-deficit analyses are discussed. Copyright © 2018 The Author(s). Published by Elsevier Ltd.. All rights reserved.

Deviations in gait metrics in patients with chronic ankle instability: a case control study.

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Gigi, Roy; Haim, Amir; Luger, Elchanan; Segal, Ganit; Melamed, Eyal; Beer, Yiftah; Nof, Matityahu; Nyska, Meir; Elbaz, Avi

2015-01-01

Gait metric alterations have been previously reported in patients suffering from chronic ankle instability (CAI). Previous studies of gait in this population have been comprised of relatively small cohorts, and the findings of these studies are not uniform. The objective of the present study was to examine spatiotemporal gait metrics in patients with CAI and examine the relationship between self-reported disease severity and the magnitude of gait abnormalities. Forty-four patients with CAI were identified and compared to 53 healthy controls. Patients were evaluated with spatiotemporal gait analysis via a computerized mat and with the Short Form (SF) - 36 health survey. Patients with CAI were found to walk with approximately 16% slower walking velocity, 9% lower cadence and approximately 7% lower step length. Furthermore, the base of support, during walking, in the CAI group was approximately 43% wider, and the single limb support phase was 3.5% shorter compared to the control group. All of the SF-36 8-subscales, as well as the SF-36 physical component summary and SF-36 mental component summary, were significantly lower in patients with CAI compared to the control group. Finally, significant correlations were found between most of the objective gait measures and the SF-36 mental component summary and SF-36 physical component summary. The results outline a gait profile for patients suffering from CAI. Significant differences were found in most spatiotemporal gait metrics. An important finding was a significantly wider base of support. It may be speculated that these gait alterations may reflect a strategy to deal with imbalance and pain. These findings suggest the usefulness of gait metrics, alongside with the use of self-evaluation questionnaires, in assessing disease severity of patients with CAI.

Human Gait Recognition Based on Multiview Gait Sequences

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Xiaxi Huang

2008-05-01

Full Text Available Most of the existing gait recognition methods rely on a single view, usually the side view, of the walking person. This paper investigates the case in which several views are available for gait recognition. It is shown that each view has unequal discrimination power and, therefore, should have unequal contribution in the recognition process. In order to exploit the availability of multiple views, several methods for the combination of the results that are obtained from the individual views are tested and evaluated. A novel approach for the combination of the results from several views is also proposed based on the relative importance of each view. The proposed approach generates superior results, compared to those obtained by using individual views or by using multiple views that are combined using other combination methods.

Absorbed fractions in a voxel-based phantom calculated with the MCNP-4B code.

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Yoriyaz, H; dos Santos, A; Stabin, M G; Cabezas, R

2000-07-01

A new approach for calculating internal dose estimates was developed through the use of a more realistic computational model of the human body. The present technique shows the capability to build a patient-specific phantom with tomography data (a voxel-based phantom) for the simulation of radiation transport and energy deposition using Monte Carlo methods such as in the MCNP-4B code. MCNP-4B absorbed fractions for photons in the mathematical phantom of Snyder et al. agreed well with reference values. Results obtained through radiation transport simulation in the voxel-based phantom, in general, agreed well with reference values. Considerable discrepancies, however, were found in some cases due to two major causes: differences in the organ masses between the phantoms and the occurrence of organ overlap in the voxel-based phantom, which is not considered in the mathematical phantom.

Brain involvement in patients with inflammatory bowel disease: a voxel-based morphometry and diffusion tensor imaging study.

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Zikou, Anastasia K; Kosmidou, Maria; Astrakas, Loukas G; Tzarouchi, Loukia C; Tsianos, Epameinondas; Argyropoulou, Maria I

2014-10-01

To investigate structural brain changes in inflammatory bowel disease (IBD). Brain magnetic resonance imaging (MRI) was performed on 18 IBD patients (aged 45.16 ± 14.71 years) and 20 aged-matched control subjects. The imaging protocol consisted of a sagittal-FLAIR, a T1-weighted high-resolution three-dimensional spoiled gradient-echo sequence, and a multisession spin-echo echo-planar diffusion-weighted sequence. Differences between patients and controls in brain volume and diffusion indices were evaluated using the voxel-based morphometry (VBM) and tract-based spatial statistics (TBSS) methods, respectively. The presence of white-matter hyperintensities (WMHIs) was evaluated on FLAIR images. VBM revealed decreased grey matter (GM) volume in patients in the fusiform and the inferior temporal gyrus bilaterally, the right precentral gyrus, the right supplementary motor area, the right middle frontal gyrus and the left superior parietal gyrus (p tensor imaging detects microstructural brain abnormalities in IBD. • Voxel based morphometry reveals brain atrophy in IBD.

Crowd-Sourced Amputee Gait Data: A Feasibility Study Using YouTube Videos of Unilateral Trans-Femoral Gait.

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James Gardiner

Full Text Available Collecting large datasets of amputee gait data is notoriously difficult. Additionally, collecting data on less prevalent amputations or on gait activities other than level walking and running on hard surfaces is rarely attempted. However, with the wealth of user-generated content on the Internet, the scope for collecting amputee gait data from alternative sources other than traditional gait labs is intriguing. Here we investigate the potential of YouTube videos to provide gait data on amputee walking. We use an example dataset of trans-femoral amputees level walking at self-selected speeds to collect temporal gait parameters and calculate gait asymmetry. We compare our YouTube data with typical literature values, and show that our methodology produces results that are highly comparable to data collected in a traditional manner. The similarity between the results of our novel methodology and literature values lends confidence to our technique. Nevertheless, clear challenges with the collection and interpretation of crowd-sourced gait data remain, including long term access to datasets, and a lack of validity and reliability studies in this area.

Crowd-Sourced Amputee Gait Data: A Feasibility Study Using YouTube Videos of Unilateral Trans-Femoral Gait.

Science.gov (United States)

Gardiner, James; Gunarathne, Nuwan; Howard, David; Kenney, Laurence

2016-01-01

Collecting large datasets of amputee gait data is notoriously difficult. Additionally, collecting data on less prevalent amputations or on gait activities other than level walking and running on hard surfaces is rarely attempted. However, with the wealth of user-generated content on the Internet, the scope for collecting amputee gait data from alternative sources other than traditional gait labs is intriguing. Here we investigate the potential of YouTube videos to provide gait data on amputee walking. We use an example dataset of trans-femoral amputees level walking at self-selected speeds to collect temporal gait parameters and calculate gait asymmetry. We compare our YouTube data with typical literature values, and show that our methodology produces results that are highly comparable to data collected in a traditional manner. The similarity between the results of our novel methodology and literature values lends confidence to our technique. Nevertheless, clear challenges with the collection and interpretation of crowd-sourced gait data remain, including long term access to datasets, and a lack of validity and reliability studies in this area.

Estimation of Temporal Gait Parameters Using a Wearable Microphone-Sensor-Based System

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Cheng Wang

2016-12-01

Full Text Available Most existing wearable gait analysis methods focus on the analysis of data obtained from inertial sensors. This paper proposes a novel, low-cost, wireless and wearable gait analysis system which uses microphone sensors to collect footstep sound signals during walking. This is the first time a microphone sensor is used as a wearable gait analysis device as far as we know. Based on this system, a gait analysis algorithm for estimating the temporal parameters of gait is presented. The algorithm fully uses the fusion of two feet footstep sound signals and includes three stages: footstep detection, heel-strike event and toe-on event detection, and calculation of gait temporal parameters. Experimental results show that with a total of 240 data sequences and 1732 steps collected using three different gait data collection strategies from 15 healthy subjects, the proposed system achieves an average 0.955 F1-measure for footstep detection, an average 94.52% accuracy rate for heel-strike detection and 94.25% accuracy rate for toe-on detection. Using these detection results, nine temporal related gait parameters are calculated and these parameters are consistent with their corresponding normal gait temporal parameters and labeled data calculation results. The results verify the effectiveness of our proposed system and algorithm for temporal gait parameter estimation.

Exoskeleton-assisted gait training to improve gait in individuals with spinal cord injury: a pilot randomized study.

Science.gov (United States)

Chang, Shuo-Hsiu; Afzal, Taimoor; Berliner, Jeffrey; Francisco, Gerard E

2018-01-01

Robotic wearable exoskeletons have been utilized as a gait training device in persons with spinal cord injury. This pilot study investigated the feasibility of offering exoskeleton-assisted gait training (EGT) on gait in individuals with incomplete spinal cord injury (iSCI) in preparation for a phase III RCT. The objective was to assess treatment reliability and potential efficacy of EGT and conventional physical therapy (CPT). Forty-four individuals were screened, and 13 were eligible to participate in the study. Nine participants consented and were randomly assigned to receive either EGT or CPT with focus on gait. Subjects received EGT or CPT, five sessions a week (1 h/session daily) for 3 weeks. American Spinal Injury Association (ASIA) Lower Extremity Motor Score (LEMS), 10-Meter Walk Test (10MWT), 6-Minute Walk Test (6MWT), Timed Up and Go (TUG) test, and gait characteristics including stride and step length, cadence and stance, and swing phase durations were assessed at the pre- and immediate post- training. Mean difference estimates with 95% confidence intervals were used to analyze the differences. After training, improvement was observed in the 6MWT for the EGT group. The CPT group showed significant improvement in the TUG test. Both the EGT and the CPT groups showed significant increase in the right step length. EGT group also showed improvement in the stride length. EGT could be applied to individuals with iSCI to facilitate gait recovery. The subjects were able to tolerate the treatment; however, exoskeleton size range may be a limiting factor in recruiting larger cohort of patients. Future studies with larger sample size are needed to investigate the effectiveness and efficacy of exoskeleton-assisted gait training as single gait training and combined with other gait training strategies. Clinicaltrials.org, NCT03011099, retrospectively registered on January 3, 2017.

Modification of hemiplegic compensatory gait pattern by symmetry-based motion controller of HAL.

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Kawamoto, Hiroaki; Kadone, Hideki; Sakurai, Takeru; Sankai, Yoshiyuki

2015-01-01

As one of several characteristics of hemiplegic patients after stroke, compensatory gait caused by affected limb is often seen. The purpose of this research is to apply a symmetry-based controller of a wearable type lower limb robot, Hybrid Assistive Limb (HAL) to hemiplegic patients with compensatory gait, and to investigate improvement of gait symmetry. The controller is designed respectively for swing phase and support phase according to characteristics of hemiplegic gait pattern. The controller during swing phase stores the motion of the unaffected limb and then provides motion support on the affected limb during the subsequent swing using the stored pattern to realize symmetric gait based on spontaneous limb swing. Moreover, the controller during support phase provides motion to extend hip and knee joints to support wearer's body. Clinical tests were conducted in order to assess the modification of gait symmetry. Our case study involved participation of one chronic stroke patient who performs abnormally-compensatory gait for both of the affected and unaffected limbs. As a result, the patient's gait symmetry was improved by providing motion support during the swing phase on the affected side and motion constraint during the support phase on the unaffected side. The study showed promising basis for the effectiveness of the controller for the future clinical study.

GaitaBase: Web-based repository system for gait analysis.

Science.gov (United States)

Tirosh, Oren; Baker, Richard; McGinley, Jenny

2010-02-01

The need to share gait analysis data to improve clinical decision support has been recognised since the early 1990s. GaitaBase has been established to provide a web-accessible repository system of gait analysis data to improve the sharing of data across local and international clinical and research community. It is used by several clinical and research groups across the world providing cross-group access permissions to retrieve and analyse the data. The system is useful for bench-marking and quality assurance, clinical consultation, and collaborative research. It has the capacity to increase the population sample size and improve the quality of 'normative' gait data. In addition the accumulated stored data may facilitate clinicians in comparing their own gait data with others, and give a valuable insight into how effective specific interventions have been for others. 2009 Elsevier Ltd. All rights reserved.

Gait Correlation Analysis Based Human Identification

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Jinyan Chen

2014-01-01

Full Text Available Human gait identification aims to identify people by a sequence of walking images. Comparing with fingerprint or iris based identification, the most important advantage of gait identification is that it can be done at a distance. In this paper, silhouette correlation analysis based human identification approach is proposed. By background subtracting algorithm, the moving silhouette figure can be extracted from the walking images sequence. Every pixel in the silhouette has three dimensions: horizontal axis (x, vertical axis (y, and temporal axis (t. By moving every pixel in the silhouette image along these three dimensions, we can get a new silhouette. The correlation result between the original silhouette and the new one can be used as the raw feature of human gait. Discrete Fourier transform is used to extract features from this correlation result. Then, these features are normalized to minimize the affection of noise. Primary component analysis method is used to reduce the features’ dimensions. Experiment based on CASIA database shows that this method has an encouraging recognition performance.

A voxel-based technique to estimate the volume of trees from terrestrial laser scanner data

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Bienert, A.; Hess, C.; Maas, H.-G.; von Oheimb, G.

2014-06-01

The precise determination of the volume of standing trees is very important for ecological and economical considerations in forestry. If terrestrial laser scanner data are available, a simple approach for volume determination is given by allocating points into a voxel structure and subsequently counting the filled voxels. Generally, this method will overestimate the volume. The paper presents an improved algorithm to estimate the wood volume of trees using a voxel-based method which will correct for the overestimation. After voxel space transformation, each voxel which contains points is reduced to the volume of its surrounding bounding box. In a next step, occluded (inner stem) voxels are identified by a neighbourhood analysis sweeping in the X and Y direction of each filled voxel. Finally, the wood volume of the tree is composed by the sum of the bounding box volumes of the outer voxels and the volume of all occluded inner voxels. Scan data sets from several young Norway maple trees (Acer platanoides) were used to analyse the algorithm. Therefore, the scanned trees as well as their representing point clouds were separated in different components (stem, branches) to make a meaningful comparison. Two reference measurements were performed for validation: A direct wood volume measurement by placing the tree components into a water tank, and a frustum calculation of small trunk segments by measuring the radii along the trunk. Overall, the results show slightly underestimated volumes (-0.3% for a probe of 13 trees) with a RMSE of 11.6% for the individual tree volume calculated with the new approach.

Segmentation Based Classification of 3D Urban Point Clouds: A Super-Voxel Based Approach with Evaluation

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Laurent Trassoudaine

2013-03-01

Full Text Available Segmentation and classification of urban range data into different object classes have several challenges due to certain properties of the data, such as density variation, inconsistencies due to missing data and the large data size that require heavy computation and large memory. A method to classify urban scenes based on a super-voxel segmentation of sparse 3D data obtained from LiDAR sensors is presented. The 3D point cloud is first segmented into voxels, which are then characterized by several attributes transforming them into super-voxels. These are joined together by using a link-chain method rather than the usual region growing algorithm to create objects. These objects are then classified using geometrical models and local descriptors. In order to evaluate the results, a new metric that combines both segmentation and classification results simultaneously is presented. The effects of voxel size and incorporation of RGB color and laser reflectance intensity on the classification results are also discussed. The method is evaluated on standard data sets using different metrics to demonstrate its efficacy.

Do manual and voxel-based morphometry measure the same? – A proof of concept study

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Niels K. Focke

2014-04-01

Full Text Available Voxel-based morphometry (VBM is a commonly used method to study volumetric variations on a whole brain basis. However it is often criticised for potential confounds, mainly based on imperfect spatial registration. We therefore aimed to evaluate if VBM and gold-standard manual volumetry are measuring the same effects with respect to subcortical grey matter volumes. Manual regions-of-interest (ROIs were drawn in the hippocampus, amygdala, nucleus accumbens, thalamus, putamen, pallidum and caudate nucleus bilaterally. Resulting volumes were used for a whole brain VBM correlation analysis with SPM8. The hippocampus, amygdala, putamen and caudate nucleus were correctly identified by SPM using the contemporary high-dimensional normalization (DARTEL toolbox. This strongly suggests that VBM and manual volumetry both are indeed measuring the same effects with regard to subcortical brain structures.

WE-D-BRE-06: Quantification of Dose-Response for High Grade Esophagtis Patients Using a Novel Voxel-To-Voxel Method

International Nuclear Information System (INIS)

Niedzielski, J; Martel, M; Tucker, S; Gomez, D; Court, L; Yang, J; Briere, T

2014-01-01

Purpose: Radiation induces an inflammatory response in the esophagus, discernible on CT studies. This work objectively quantifies the voxel esophageal radiation-response for patients with acute esophagitis. This knowledge is an important first-step towards predicting the effect of complex dose distributions on patient esophagitis symptoms. Methods: A previously validated voxel-based methodology of quantifying radiation esophagitis severity was used to identify the voxel dose-response for 18 NSCLC patients with severe esophagitis (CTCAE grading criteria, grade2 or higher). The response is quantified as percent voxel volume change for a given dose. During treatment (6–8 weeks), patients had weekly 4DCT studies and esophagitis scoring. Planning CT esophageal contours were deformed to each weekly CT using a demons DIR algorithm. An algorithm using the Jacobian Map from the DIR of the planning CT to all weekly CTs was used to quantify voxel-volume change, along with corresponding delivered voxel dose, to the planning voxel. Dose for each voxel for each time-point was calculated on each previous weekly CT image, and accumulated using DIR. Thus, for each voxel, the volume-change and delivered dose was calculated for each time-point. The data was binned according to when the volume-change first increased by a threshold volume (10%–100%, in 10% increments), and the average delivered dose calculated for each bin. Results: The average dose resulting in a voxel volume increase of 10–100% was 21.6 to 45.9Gy, respectively. The mean population dose to give a 50% volume increase was 36.3±4.4Gy, (range:29.8 to 43.5Gy). The average week of 50% response was 4.1 (range:4.9 to 2.8 weeks). All 18 patients showed similar dose to first response curves, showing a common trend in the initial inflammatoryresponse. Conclusion: We extracted the dose-response curve of the esophagus on a voxel-to-voxel level. This may be useful for estimating the esophagus response (and patient symptoms

Creativity and borderline personality disorder: evidence from a voxel-based morphometry study.

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Leutgeb, Verena; Ille, Rottraut; Wabnegger, Albert; Schienle, Anne; Schöggl, Helmut; Weber, Bernhard; Papousek, Ilona; Weiss, Elisabeth M; Fink, Andreas

2016-05-01

Throughout the history, various examples of eminent creative people suffering from mental disorders along with some empirical research reports strengthened the idea of a potential link between creativity and psychopathology. This study investigated different facets of psychometrically determined creativity in 20 females diagnosed with borderline personality disorder (BPD) relative to 19 healthy female controls. In addition, group differences in grey matter (GM) were examined. Behavioural findings revealed no significant differences between the BPD group and healthy controls with respect to verbal and figural-graphic creative task performance and creativity-related personality characteristics. Whole-brain voxel-based morphometry analyses revealed a distinct pattern of GM reductions in the BPD group (relative to controls) in a network of brain regions closely associated with various cognitive and emotional functions (including the bilateral orbital inferior frontal gyri and the left superior temporal gyrus), partly overlapping with creativity-related brain regions. Correlation analyses moreover revealed that in the BPD group GM reductions in the orbital parts of the inferior and middle frontal gyri were associated with lower levels of creativity. This study provides no indications in favour of the putative link between creativity and psychopathology, as sometimes reported in the literature.

Measuring medial longitudinal arch deformation during gait. A reliability study

DEFF Research Database (Denmark)

Bencke, Jesper; Christiansen, Ditte; Jensen, Anne Kathrine Bendrup

2012-01-01

during gait and to compare this method with a static measure and a 2D dynamic method. Fifty-two feet (26 healthy male participants) were tested twice 4-9 days apart in a biomechanical gait analysis laboratory using a 3D three-marker foot model, a 2D video-based model for the measurement of MLAD during...

An optimized voxel-based morphometry MRI study of the brain in patients with first episode schizophrenia

International Nuclear Information System (INIS)

Lv Su; Huang Xiaoqi; Tang Hehan; Gong Qiyong; Ouyang Luo; Deng Wei; Jiang Lijun; Li Tao

2007-01-01

Objective: To evaluate the structural differences between patients with first episode schizophrenia and normal controls using optimized voxel-based morphometry (VBM) study. Methods: High resolution T 1 weighted images were obtained using 3.0 T MR from 13 first-episode, untreated schizophrenia and 13 age, sex, handedness matched normal controls. Images were preprocessed by employing the optimized VBM and two sample t-test was used to detect differences between patients and normal controls with respect to both density and volume of gray matter in the brain. Results Patients with schizophrenia had significant lower gray matter density and gray matter volume generally distributed among bilateral hemispheres, especially in bilateral frontal and temporal lobes. However, no significant increase of gray matter density and gray matter volume was observed in these patients. Conclusions: Optimized voxel-based morphometry study is an automatic and effective method to study psychological diseases such as schizophrenia. Compared with normal controls, patients with schizophrenia had significantly lower gray matter density and gray matter volume across the bilateral hemispheres. (authors)

Gray matter changes in subjects at high risk for developing psychosis and first-episode schizophrenia: a voxel-based structural MRI study

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Kazue eNakamura

2013-03-01

Full Text Available Objectives: The aim of the present study was to use a voxel-based MRI method to investigate the neuroanatomical characteristics in subjects at high risk of developing psychosis compared with those of healthy controls and first-episode schizophrenia patients. Methods: This study included 14 subjects with at-risk mental state (ARMS, 34 patients with first-episode schizophrenia, and 51 healthy controls. We used voxel-based morphometry (VBM with the Diffeomorphic Anatomical Registration Through Exponentiated Lie Algebra (DARTEL tools to investigate the whole-brain difference in gray matter volume among the three groups. Results: Compared with the healthy controls, the schizophrenia patients showed significant gray matter reduction in the left anterior cingulate gyrus. There was no significant difference in the gray matter volume between the ARMS and other groups. Conclusion: The present study suggests that alteration of the anterior cingulate gyrus may be associated with development of frank psychosis. Further studies with a larger ARMS subjects would be required to examine the potential role of neuroimaging methods in the prediction of future transition into psychosis.

Effect of 6-month community-based exercise interventions on gait and functional fitness of an older population: a quasi-experimental study

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Ramalho F

2018-04-01

Full Text Available Fátima Ramalho,1,2 Rita Santos-Rocha,1,2 Marco Branco,1,2 Vera Moniz-Pereira,2 Helô-Isa André,2 António P Veloso,2 Filomena Carnide2 1Sport Sciences School of Rio Maior (ESDRM, Polytechnic Institute of Santarém, Rio Maior, Portugal; 2Laboratory of Biomechanics and Functional Morphology, Interdisciplinary Centre for the Study of Human Performance (CIPER, Faculty of Human Kinetics (FMH, University of Lisbon, Cruz Quebrada, Portugal Background: Gait ability in older adults has been associated with independent living, increased survival rates, fall prevention, and quality of life. There are inconsistent findings regarding the effects of exercise interventions in the maintenance of gait parameters.Objectives: The aim of the study was to analyze the effects of a community-based periodized exercise intervention on the improvement of gait parameters and functional fitness in an older adult group compared with a non-periodized program.Methods: A quasi-experimental study with follow-up was performed in a periodized exercise group (N=15 and in a non-periodized exercise group (N=13. The primary outcomes were plantar pressure gait parameters, and the secondary outcomes were physical activity, aerobic endurance, lower limb strength, agility, and balance. These variables were recorded at baseline and after 6 months of intervention.Results: Both programs were tailored to older adults’ functional fitness level and proved to be effective in reducing the age-related decline regarding functional fitness and gait parameters. Gait parameters were sensitive to both the exercise interventions. Conclusion: These exercise protocols can be used by exercise professionals in prescribing community exercise programs, as well as by health professionals in promoting active aging. Keywords: mobility, community exercise programs, active aging, plantar pressure analysis, ground reaction forces, gait properties

Assessment of memory/attention impairment in children with primary nocturnal enuresis: A voxel-based morphometry study

International Nuclear Information System (INIS)

Yu, Bing; Kong, Fanxing; Peng, Miao; Ma, Hongwei; Liu, Na; Guo, Qiyong

2012-01-01

Aim: Assessment of memory/attention impairment and related exploration of the gray matter differential MR density variations between children with and without primary nocturnal enuresis (PNE) using voxel-based morphometry (VBM) methodology is the aim of the present study. Methods: A total of 75 right-handed PNE children (M/F = 39:36, average age 10.4 ± 1.3 years) and 72 age-matched, right-handed, healthy controls (M/F = 40:32, 10.0 ± 1.2 years) were recruited for the study. First, intelligence tests were performed using the China-Wechsler Intelligence Scale for Children (C-WISC) in both PNE and control children. The full intelligence quotient (FIQ), verbal IQ (VIQ), performance IQ (PIQ), and memory/caution (M/C) factor were measured. Voxel-based morphometry (VBM) was performed using high resolution 3 Tesla T1-weighted MR images, processed using VBM5 in the PNE and control children. Student's t-test or Mann–Whitney U test were performed to analyze the difference in the gray matter density (GMD) between the PNE and control children. Results: The FIQ, VIQ, and PIQ in the PNE group were within the normal range and did not significantly differ from the control group, though the M/C factor was statistically lower in the PNE group. Compared with normal controls, PNE children exhibited lower GMD in the right dorsolateral prefrontal cortex (DLPFC) and the left cerebellum (P < 0.001). Conclusion: Impairment in memory/attention was detected in PNE children, and the structural abnormalities of the right DLPFC and left cerebellum are likely to be implicated in these deficits.

Voxel-based model construction from colored tomographic images

International Nuclear Information System (INIS)

Loureiro, Eduardo Cesar de Miranda

2002-07-01

This work presents a new approach in the construction of voxel-based phantoms that was implemented to simplify the segmentation process of organs and tissues reducing the time used in this procedure. The segmentation process is performed by painting tomographic images and attributing a different color for each organ or tissue. A voxel-based head and neck phantom was built using this new approach. The way as the data are stored allows an increasing in the performance of the radiation transport code. The program that calculates the radiation transport also works with image files. This capability allows image reconstruction showing isodose areas, under several points of view, increasing the information to the user. Virtual X-ray photographs can also be obtained allowing that studies could be accomplished looking for the radiographic techniques optimization assessing, at the same time, the doses in organs and tissues. The accuracy of the program here presented, called MCvoxEL, that implements this new approach, was tested by comparison to results from two modern and well-supported Monte Carlo codes. Dose conversion factors for parallel X-ray exposure were also calculated. (author)

Efficiency factors for Phoswich based lung monitor using ICRP Voxel phantoms

International Nuclear Information System (INIS)

Manohari, M.; Mathiyarasu, R.; Rajagopal, V.; Jose, M.T.; Venkatraman, B.

2016-01-01

The actinide contamination in lungs is measured either using array of HPGe detector or Phoswich based lung monitors. This paper discusses the results obtained during numerical calibration of Phoswich based lung counting system using ICRP VOXEL phantoms. The results are also compared with measured efficiency values obtained using LLNL phantom. The efficiency factors of 241 Am present in the lungs for phoswich detector was simulated using ICRP male voxel phantom and compared with experimentally observed values using LLNL Phantom. The observed deviation is 12%. The efficiency of the same for female subjects was estimated using ICRP female voxel phantom for both supine and posterior geometries

Effect of Experimental Thyrotoxicosis on Brain Gray Matter: A Voxel-Based Morphometry Study.

Science.gov (United States)

Göbel, Anna; Heldmann, Marcus; Göttlich, Martin; Dirk, Anna-Luise; Brabant, Georg; Münte, Thomas F

2015-09-01

Hyper-as well hypothyroidism have an effect on behavior and brain function. Moreover, during development thyroid hormones influence brain structure. This study aimed to demonstrate an effect of experimentally induced hyperthyroidism on brain gray matter in healthy adult humans. High-resolution 3D T1-weighted images were acquired in 29 healthy young subjects prior to as well as after receiving 250 µg of T4 per day for 8 weeks. Voxel-based morphometry analysis was performed using Statistical Parametric Mapping 8 (SPM8). Laboratory testing confirmed the induction of hyperthyroidism. In the hyperthyroid condition, gray matter volumes were increased in the right posterior cerebellum (lobule VI) and decreased in the bilateral visual cortex and anterior cerebellum (lobules I-IV) compared to the euthyroid condition. Our study provides evidence that short periods of hyperthyroidism induce distinct alterations in brain structures of cerebellar regions that have been associated with sensorimotor functions as well as working memory in the literature.

Guidelines for Assessment of Gait and Reference Values for Spatiotemporal Gait Parameters in Older Adults: The Biomathics and Canadian Gait Consortiums Initiative

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Olivier Beauchet

2017-08-01

Full Text Available Background: Gait disorders, a highly prevalent condition in older adults, are associated with several adverse health consequences. Gait analysis allows qualitative and quantitative assessments of gait that improves the understanding of mechanisms of gait disorders and the choice of interventions. This manuscript aims (1 to give consensus guidance for clinical and spatiotemporal gait analysis based on the recorded footfalls in older adults aged 65 years and over, and (2 to provide reference values for spatiotemporal gait parameters based on the recorded footfalls in healthy older adults free of cognitive impairment and multi-morbidities.Methods: International experts working in a network of two different consortiums (i.e., Biomathics and Canadian Gait Consortium participated in this initiative. First, they identified items of standardized information following the usual procedure of formulation of consensus findings. Second, they merged databases including spatiotemporal gait assessments with GAITRite® system and clinical information from the “Gait, cOgnitiOn & Decline” (GOOD initiative and the Generation 100 (Gen 100 study. Only healthy—free of cognitive impairment and multi-morbidities (i.e., ≤ 3 therapeutics taken daily—participants aged 65 and older were selected. Age, sex, body mass index, mean values, and coefficients of variation (CoV of gait parameters were used for the analyses.Results: Standardized systematic assessment of three categories of items, which were demographics and clinical information, and gait characteristics (clinical and spatiotemporal gait analysis based on the recorded footfalls, were selected for the proposed guidelines. Two complementary sets of items were distinguished: a minimal data set and a full data set. In addition, a total of 954 participants (mean age 72.8 ± 4.8 years, 45.8% women were recruited to establish the reference values. Performance of spatiotemporal gait parameters based on the recorded

Gait as evidence

DEFF Research Database (Denmark)

Lynnerup, Niels; Larsen, Peter Kastmand

2014-01-01

This study examines what in Denmark may constitute evidence based on forensic anthropological gait analyses, in the sense of pointing to a match (or not) between a perpetrator and a suspect, based on video and photographic imagery. Gait and anthropometric measures can be used when direct facial...

Automated health alerts from Kinect-based in-home gait measurements.

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Stone, Erik E; Skubic, Marjorie; Back, Jessica

2014-01-01

A method for automatically generating alerts to clinicians in response to changes in in-home gait parameters is investigated. Kinect-based gait measurement systems were installed in apartments in a senior living facility. The systems continuously monitored the walking speed, stride time, and stride length of apartment residents. A framework for modeling uncertainty in the residents' gait parameter estimates, which is critical for robust change detection, is developed; along with an algorithm for detecting changes that may be clinically relevant. Three retrospective case studies, of individuals who had their gait monitored for periods ranging from 12 to 29 months, are presented to illustrate use of the alert method. Evidence suggests that clinicians could be alerted to health changes at an early stage, while they are still small and interventions may be most successful. Additional potential uses are also discussed.

The neural substrates of procrastination: A voxel-based morphometry study.

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Hu, Yue; Liu, Peiwei; Guo, Yiqun; Feng, Tingyong

2018-03-01

Procrastination is a pervasive phenomenon across different cultures and brings about lots of serious consequences, including performance, subjective well-being, and even public policy. However, little is known about the neural substrates of procrastination. In order to shed light upon this question, we investigated the neuroanatomical substrates of procrastination across two independent samples using voxel-based morphometry (VBM) method. The whole-brain analysis showed procrastination was positively correlated with the graymatter (GM) volume of clusters in the parahippocampal gyrus (PHG) and the orbital frontal cortex (OFC), while negatively correlated with the GM volume of clusters in the inferior frontal gyrus (IFG) and the middle frontal gyrus (MFG) in sample one (151 participants). We further conducted a verification procedure on another sample (108 participants) using region-of-interest analysis to examine the reliability of these results. Results showed procrastination can be predicted by the GM volume of the OFC and the MFG. The present findings suggest that the MFG and OFC, which are the key regions of self-control and emotion regulation, may play an important role in procrastination. Copyright © 2018 Elsevier Inc. All rights reserved.

A study of the passive gait of a compass-like biped robot: Symmetry and chaos

International Nuclear Information System (INIS)

Goswami, A.; Espiau, B.; Thuilot, B.

1998-01-01

The focus of this work is a systematic study of the passive gait of a compass-like planar, biped robot on inclined slopes. The robot is kinematically equivalent to a double pendulum, possessing two kneeless legs with point masses and a third point mass at the hip joint. Three parameters, namely, the ground-slope angle and the normalized mass and length of the robot describe its gait. The authors show that in response to a continuous change in any one of its parameters, the symmetric and steady stable gait of the unpowered robot gradually evolves through a regime of bifurcations characterized by progressively complicated asymmetric gaits, eventually arriving at an apparently chaotic gait where not two steps are identical. The robot can maintain this gait indefinitely. A necessary (but not sufficient) condition for the stability of such gaits is the contraction of the phase-fluid volume. For this frictionless robot, the volume contraction, which the authors compute, is caused by the dissipative effects of the ground-impact model. In the chaotic regime, the fractal dimension of the robot's strange attractor (2.07) compared to its state-space dimension (4) also reveals strong contraction. The authors present a novel graphical technique based on the first return map that compactly captures the entire evolution of the gait, from symmetry to chaos. Additional passive dissipative elements in the robot joint results in a significant improvement in the stability and the versatility of the gait, and provide a rich repertoire for simple controls laws

Gait adjustments in obstacle crossing, gait initiation and gait termination after a recent lower limb amputation

NARCIS (Netherlands)

Vrieling, Aline H.; van Keeken, Helco G.; Schoppen, Tanneke; Hof, At L.; Otten, Bert; Halbertsma, Jan P. K.; Postema, Klaas

Objective: To describe the adjustments in gait characteristics of obstacle crossing, gait initiation and gait termination that occur in subjects with a recent lower limb amputation during the rehabilitation process. Design: Prospective and descriptive study. Subjects: Fourteen subjects with a recent

Neuroanatomical correlates of time perspective: A voxel-based morphometry study.

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Chen, Zhiyi; Guo, Yiqun; Feng, Tingyong

2018-02-26

Previous studies indicated that time perspective can affect many behaviors, such as decisions, risk taking, substance abuse and health behaviors. However, very little is known about the neural substrates of time perspective (TP). To address this question, we characterized different dimensions of TP (including the Past, Present, and Future TP) using standardized Zimbardo Time Perspective Inventory (ZTPI), and quantified the gray matter volume using voxel-based morphometry (VBM) method across two independent samples. Our whole-brain analysis (sample 1, N=150) revealed Past-Negative TP was positively correlated with the GMV of a cluster in LPFC whereas Past-Positive was negatively correlated with the GMV in OFC, and Future TP was negatively correlated with GMV in mPFC. Moreover, two present scales (Present-Hedonistic and Present-Fatalistic TPs) were positively correlated with the GMV of regions in MTG and precuneus, respectively. We further examined the reliability of these correlations between multidimensional TPs and neuroanatomical structures in another independent sample (sample 2, N=58). Results verified our findings that GMV in LPFC could predict Past-Negative TP while GMV in OFC could predict Past-Positive TP, and the GMV in MTG could predict Present-Hedonistic while the GMV in presuneus could predict Present-Fatalistic, as well as the GMV in mPFC could predict Future TP. Thus, our findings suggest that the existence of selective neural basis underlying TPs, and further provide the stable biomarkers for multidimensional TPs. Copyright © 2017 Elsevier B.V. All rights reserved.

Light regimes in Populus plantations using the Voxel-based Light Interception Model

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Van der Zande, D.; Dieussart, K.; Stuckens, J.; Verstraeten, W.W.; Coppin, P.

2011-01-01

Three-dimensional light interception by three uniform Populus canopies was studied using the Voxel-based Light Interception Model (VLIM) in combination with ground-based Light Detection and Ranging (LiDAR) measurements. As the VLIM was developed and validated in a virtual environment to ensure

VOXEL-BASED APPROACH FOR ESTIMATING URBAN TREE VOLUME FROM TERRESTRIAL LASER SCANNING DATA

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C. Vonderach

2012-07-01

Full Text Available The importance of single trees and the determination of related parameters has been recognized in recent years, e.g. for forest inventories or management. For urban areas an increasing interest in the data acquisition of trees can be observed concerning aspects like urban climate, CO2 balance, and environmental protection. Urban trees differ significantly from natural systems with regard to the site conditions (e.g. technogenic soils, contaminants, lower groundwater level, regular disturbance, climate (increased temperature, reduced humidity and species composition and arrangement (habitus and health status and therefore allometric relations cannot be transferred from natural sites to urban areas. To overcome this problem an extended approach was developed for a fast and non-destructive extraction of branch volume, DBH (diameter at breast height and height of single trees from point clouds of terrestrial laser scanning (TLS. For data acquisition, the trees were scanned with highest scan resolution from several (up to five positions located around the tree. The resulting point clouds (20 to 60 million points are analysed with an algorithm based on voxel (volume elements structure, leading to an appropriate data reduction. In a first step, two kinds of noise reduction are carried out: the elimination of isolated voxels as well as voxels with marginal point density. To obtain correct volume estimates, the voxels inside the stem and branches (interior voxels where voxels contain no laser points must be regarded. For this filling process, an easy and robust approach was developed based on a layer-wise (horizontal layers of the voxel structure intersection of four orthogonal viewing directions. However, this procedure also generates several erroneous "phantom" voxels, which have to be eliminated. For this purpose the previous approach was extended by a special region growing algorithm. In a final step the volume is determined layer-wise based on the

An Ambulatory System for Gait Monitoring Based on Wireless Sensorized Insoles

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González, Iván; Fontecha, Jesús; Hervás, Ramón; Bravo, José

2015-01-01

A new gait phase detection system for continuous monitoring based on wireless sensorized insoles is presented. The system can be used in gait analysis mobile applications, and it is designed for real-time demarcation of gait phases. The system employs pressure sensors to assess the force exerted by each foot during walking. A fuzzy rule-based inference algorithm is implemented on a smartphone and used to detect each of the gait phases based on the sensor signals. Additionally, to provide a solution that is insensitive to perturbations caused by non-walking activities, a probabilistic classifier is employed to discriminate walking forward from other low-level activities, such as turning, walking backwards, lateral walking, etc. The combination of these two algorithms constitutes the first approach towards a continuous gait assessment system, by means of the avoidance of non-walking influences. PMID:26184199

An Ambulatory System for Gait Monitoring Based on Wireless Sensorized Insoles

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Iván González

2015-07-01

Full Text Available A new gait phase detection system for continuous monitoring based on wireless sensorized insoles is presented. The system can be used in gait analysis mobile applications, and it is designed for real-time demarcation of gait phases. The system employs pressure sensors to assess the force exerted by each foot during walking. A fuzzy rule-based inference algorithm is implemented on a smartphone and used to detect each of the gait phases based on the sensor signals. Additionally, to provide a solution that is insensitive to perturbations caused by non-walking activities, a probabilistic classifier is employed to discriminate walking forward from other low-level activities, such as turning, walking backwards, lateral walking, etc. The combination of these two algorithms constitutes the first approach towards a continuous gait assessment system, by means of the avoidance of non-walking influences.

Intensive gait training in toddlers with cerebral palsy: A pilot study

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Anna Herskind

2016-07-01

Full Text Available Background: Reduced muscle growth may be involved in the development of contractures in children with cerebral palsy (CP. Here, we report data from a pilot study of intensive gait training in CP toddlers. Methods: Five children with CP aged 8-30 months performed activity-based gait training for one hour/day, five days/week for three consecutive months. Included children were diagnosed with spastic CP, had a Gross Motor Function Classification System (GMFCS score of I–II, and were not epileptic. All children wore pedometers during training. Before and after the training period, kinematic and qualitative gait analysis, clinical and objective evaluation of spasticity, Gross Motor Function Measure-66 (GMFM-66, and ultrasound of the affected medial gastrocnemius (MG muscle were performed. Two children were also tested before and after three months of receiving only standard care (SC. Results: On average 1410 steps/session were logged during 63 days of training. More steps were achieved at home than at a central facility. During training, MG muscle volume increased significantly, while it decreased for SC children. Gait improved qualitatively in all children, and GMFM-66 score improved in four of the five children. Similar improvements were seen among the SC children. Two children had pathologically increased muscle stiffness prior to training, which was reduced during training. Reflex stiffness was unchanged in all five children. Conclusions: This pilot study suggests that intensive gait training may increase muscle volume, improve walking skills and reduce passive muscle stiffness in toddlers with CP.

Assessment of memory/attention impairment in children with primary nocturnal enuresis: A voxel-based morphometry study

Energy Technology Data Exchange (ETDEWEB)

Yu, Bing, E-mail: yubing@sj-hospital.org [Department of Radiology, Shengjing Hospital of China Medical University, Shenyang 110004 (China); Kong, Fanxing, E-mail: kongfx@sj-hospital.org [Department of Radiology, Shengjing Hospital of China Medical University, Shenyang 110004 (China); Peng, Miao, E-mail: pengm@sj-hospital.org [Psychological Outpatient Service, Shengjing Hospital of China Medical University, Shenyang 110004 (China); Ma, Hongwei, E-mail: mahongwei1960@hotmail.com [Department of Pediatrics, Shengjing Hospital of China Medical University, Shenyang 110004 (China); Liu, Na, E-mail: liuna.916@163.com [Department of Radiology, the People' s Hospital of Liaoning Province, Shenyang 110016 (China); Guo, Qiyong, E-mail: guoqy@sj-hospital.org [Department of Radiology, Shengjing Hospital of China Medical University, Shenyang 110004 (China)

2012-12-15

Aim: Assessment of memory/attention impairment and related exploration of the gray matter differential MR density variations between children with and without primary nocturnal enuresis (PNE) using voxel-based morphometry (VBM) methodology is the aim of the present study. Methods: A total of 75 right-handed PNE children (M/F = 39:36, average age 10.4 ± 1.3 years) and 72 age-matched, right-handed, healthy controls (M/F = 40:32, 10.0 ± 1.2 years) were recruited for the study. First, intelligence tests were performed using the China-Wechsler Intelligence Scale for Children (C-WISC) in both PNE and control children. The full intelligence quotient (FIQ), verbal IQ (VIQ), performance IQ (PIQ), and memory/caution (M/C) factor were measured. Voxel-based morphometry (VBM) was performed using high resolution 3 Tesla T1-weighted MR images, processed using VBM5 in the PNE and control children. Student's t-test or Mann–Whitney U test were performed to analyze the difference in the gray matter density (GMD) between the PNE and control children. Results: The FIQ, VIQ, and PIQ in the PNE group were within the normal range and did not significantly differ from the control group, though the M/C factor was statistically lower in the PNE group. Compared with normal controls, PNE children exhibited lower GMD in the right dorsolateral prefrontal cortex (DLPFC) and the left cerebellum (P < 0.001). Conclusion: Impairment in memory/attention was detected in PNE children, and the structural abnormalities of the right DLPFC and left cerebellum are likely to be implicated in these deficits.

Automated voxel-based analysis of brain perfusion SPECT for vasospasm after subarachnoid haemorrhage

International Nuclear Information System (INIS)

Iwabuchi, S.; Yokouchi, T.; Hayashi, M.; Kimura, H.; Tomiyama, A.; Hirata, Y.; Saito, N.; Harashina, J.; Nakayama, H.; Sato, K.; Aoki, K.; Samejima, H.; Ueda, M.; Terada, H.; Hamazaki, K.

2008-01-01

We evaluated regional cerebral blood flow (rCBF) during vasospasm after subarachnoid haemorrhage ISAH) using automated voxel-based analysis of brain perfusion single-photon emission computed tomography (SPELT). Brain perfusion SPECT was performed 7 to 10 days after onset of SAH. Automated voxel-based analysis of SPECT used a Z-score map that was calculated by comparing the patients data with a control database. In cases where computed tomography (CT) scans detected an ischemic region due to vasospasm, automated voxel-based analysis of brain perfusion SPECT revealed dramatically reduced rCBF (Z-score ≤ -4). No patients with mildly or moderately diminished rCBF (Z-score > -3) progressed to cerebral infarction. Some patients with a Z-score < -4 did not progress to cerebral infarction after active treatment with a angioplasty. Three-dimensional images provided detailed anatomical information and helped us to distinguish surgical sequelae from vasospasm. In conclusion, automated voxel-based analysis of brain perfusion SPECT using a Z-score map is helpful in evaluating decreased rCBF due to vasospasm. (author)

Does a single gait training session performed either overground or on a treadmill induce specific short-term effects on gait parameters in patients with hemiparesis? A randomized controlled study.

Science.gov (United States)

Bonnyaud, Céline; Pradon, Didier; Zory, Raphael; Bensmail, Djamel; Vuillerme, Nicolas; Roche, Nicolas

2013-01-01

Gait training for patients with hemiparesis is carried out independently overground or on a treadmill. Several studies have shown differences in hemiparetic gait parameters during overground versus treadmill walking. However, few studies have compared the effects of these 2 gait training conditions on gait parameters, and no study has compared the short-term effects of these techniques on all biomechanical gait parameters. To determine whether a gait training session performed overground or on a treadmill induces specific short-term effects on biomechanical gait parameters in patients with hemiparesis. Twenty-six subjects with hemiparesis were randomly assigned to a single session of either overground or treadmill gait training. The short-term effects on spatiotemporal, kinematic, and kinetic gait parameters were assessed using gait analysis before and immediately after the training and after a 20-minute rest. Speed, cadence, percentage of single support phase, peak knee extension, peak propulsion, and braking on the paretic side were significantly increased after the gait training session. However, there were no specific changes dependent on the type of gait training performed (overground or on a treadmill). A gait training session performed by subjects with hemiparesis overground or on a treadmill did not induce specific short-term effects on biomechanical gait parameters. The increase in gait velocity that followed a gait training session seemed to reflect specific modifications of the paretic lower limb and adaptation of the nonparetic lower limb.

Measuring Gait Quality in Parkinson’s Disease through Real-Time Gait Phase Recognition

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Ilaria Mileti

2018-03-01

Full Text Available Monitoring gait quality in daily activities through wearable sensors has the potential to improve medical assessment in Parkinson’s Disease (PD. In this study, four gait partitioning methods, two based on thresholds and two based on a machine learning approach, considering the four-phase model, were compared. The methods were tested on 26 PD patients, both in OFF and ON levodopa conditions, and 11 healthy subjects, during walking tasks. All subjects were equipped with inertial sensors placed on feet. Force resistive sensors were used to assess reference time sequence of gait phases. Goodness Index (G was evaluated to assess accuracy in gait phases estimation. A novel synthetic index called Gait Phase Quality Index (GPQI was proposed for gait quality assessment. Results revealed optimum performance (G < 0.25 for three tested methods and good performance (0.25 < G < 0.70 for one threshold method. The GPQI resulted significantly higher in PD patients than in healthy subjects, showing a moderate correlation with clinical scales score. Furthermore, in patients with severe gait impairment, GPQI was found higher in OFF than in ON state. Our results unveil the possibility of monitoring gait quality in PD through real-time gait partitioning based on wearable sensors.

A comparative study of the effects of trunk exercise program in aquatic and land-based therapy on gait in hemiplegic stroke patients.

Science.gov (United States)

Park, Byoung-Sun; Noh, Ji-Woong; Kim, Mee-Young; Lee, Lim-Kyu; Yang, Seung-Min; Lee, Won-Deok; Shin, Yong-Sub; Kim, Ju-Hyun; Lee, Jeong-Uk; Kwak, Taek-Yong; Lee, Tae-Hyun; Park, Jaehong; Kim, Junghwan

2016-06-01

[Purpose] The purpose of this study was to compare the effects of aquatic and land-based trunk exercise program on gait in stroke patients. [Subjects and Methods] The subjects were 28 hemiplegic stroke patients (20 males, 8 females). The subjects performed a trunk exercise program for a total of four weeks. [Results] Walking speed and cycle, stance phase and stride length of the affected side, and the symmetry index of the stance phase significantly improved after the aquatic and land-based trunk exercise program. [Conclusion] These results suggest that the aquatic and land-based trunk exercise program may help improve gait performance ability after stroke.

Micromechanical analysis of nanocomposites using 3D voxel based material model

DEFF Research Database (Denmark)

Mishnaevsky, Leon

2012-01-01

A computational study on the effect of nanocomposite structures on the elastic properties is carried out with the use of the 3D voxel based model of materials and the combined Voigt–Reuss method. A hierarchical voxel based model of a material reinforced by an array of exfoliated and intercalated...... nanoclay platelets surrounded by interphase layers is developed. With this model, the elastic properties of the interphase layer are estimated using the inverse analysis. The effects of aspect ratio, intercalation and orientation of nanoparticles on the elastic properties of the nanocomposites are analyzed....... For modeling the damage in nanocomposites with intercalated structures, “four phase” model is suggested, in which the strength of “intrastack interphase” is lower than that of “outer” interphase around the nanoplatelets. Analyzing the effect of nanoreinforcement in the matrix on the failure probability...

GaitKeeper: A System for Measuring Canine Gait

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Cassim Ladha

2017-02-01

Full Text Available It is understood gait has the potential to be used as a window into neurodegenerative disorders, identify markers of subclinical pathology, inform diagnostic algorithms of disease progression and measure the efficacy of interventions. Dogs’ gaits are frequently assessed in a veterinary setting to detect signs of lameness. Despite this, a reliable, affordable and objective method to assess lameness in dogs is lacking. Most described canine lameness assessments are subjective, unvalidated and at high risk of bias. This means reliable, early detection of canine gait abnormalities is challenging, which may have detrimental implications for dogs’ welfare. In this paper, we draw from approaches and technologies used in human movement science and describe a system for objectively measuring temporal gait characteristics in dogs (step-time, swing-time, stance-time. Asymmetries and variabilities in these characteristics are of known clinical significance when assessing lameness but presently may only be assessed on coarse scales or under highly instrumented environments. The system consists an inertial measurement unit, containing a 3-axis accelerometer and gyroscope coupled with a standardized walking course. The measurement unit is attached to each leg of the dog under assessment before it is walked around the course. The data by the measurement unit is then processed to identify steps and subsequently, micro-gait characteristics. This method has been tested on a cohort of 19 healthy dogs of various breeds ranging in height from 34.2 cm to 84.9 cm. We report the system as capable of making precise step delineations with detections of initial and final contact times of foot-to-floor to a mean precision of 0.011 s and 0.048 s, respectively. Results are based on analysis of 12,678 foot falls and we report a sensitivity, positive predictive value and F-score of 0.81, 0.83 and 0.82 respectively. To investigate the effect of gait on system performance

A Comparative Study of Biologically Inspired Walking Gaits through Waypoint Navigation

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Umar Asif

2011-01-01

Full Text Available This paper investigates the locomotion of a walking robot by delivering a comparative study of three different biologically inspired walking gaits, namely: tripod, ripple, and wave, in terms of ground slippage they experience while walking. The objective of this study is to identify the gait model which experiences the minimum slippage while walking on a ground with a specific coefficient of friction. To accomplish this feat, the robot is steered over a reference path using a waypoint navigation algorithm, and the divergence of the robot from the reference path is investigated in terms of slip errors. Experiments are conducted through closed-loop simulations using an open dynamics engine which emphasizes the fact that due to uneven and unsymmetrical distribution of payload in tripod and ripple gait models, the robot experiences comparatively larger drift in these gaits than when using the wave gait model in which the distribution of payload is even and symmetrical on both sides of the robot body. The paper investigates this phenomenon on the basis of force distribution of supporting legs in each gait model.

VoxelStats: A MATLAB Package for Multi-Modal Voxel-Wise Brain Image Analysis.

Science.gov (United States)

Mathotaarachchi, Sulantha; Wang, Seqian; Shin, Monica; Pascoal, Tharick A; Benedet, Andrea L; Kang, Min Su; Beaudry, Thomas; Fonov, Vladimir S; Gauthier, Serge; Labbe, Aurélie; Rosa-Neto, Pedro

2016-01-01

In healthy individuals, behavioral outcomes are highly associated with the variability on brain regional structure or neurochemical phenotypes. Similarly, in the context of neurodegenerative conditions, neuroimaging reveals that cognitive decline is linked to the magnitude of atrophy, neurochemical declines, or concentrations of abnormal protein aggregates across brain regions. However, modeling the effects of multiple regional abnormalities as determinants of cognitive decline at the voxel level remains largely unexplored by multimodal imaging research, given the high computational cost of estimating regression models for every single voxel from various imaging modalities. VoxelStats is a voxel-wise computational framework to overcome these computational limitations and to perform statistical operations on multiple scalar variables and imaging modalities at the voxel level. VoxelStats package has been developed in Matlab(®) and supports imaging formats such as Nifti-1, ANALYZE, and MINC v2. Prebuilt functions in VoxelStats enable the user to perform voxel-wise general and generalized linear models and mixed effect models with multiple volumetric covariates. Importantly, VoxelStats can recognize scalar values or image volumes as response variables and can accommodate volumetric statistical covariates as well as their interaction effects with other variables. Furthermore, this package includes built-in functionality to perform voxel-wise receiver operating characteristic analysis and paired and unpaired group contrast analysis. Validation of VoxelStats was conducted by comparing the linear regression functionality with existing toolboxes such as glim_image and RMINC. The validation results were identical to existing methods and the additional functionality was demonstrated by generating feature case assessments (t-statistics, odds ratio, and true positive rate maps). In summary, VoxelStats expands the current methods for multimodal imaging analysis by allowing the

Structural neural correlates of multitasking: A voxel-based morphometry study.

Science.gov (United States)

Zhang, Rui-Ting; Yang, Tian-Xiao; Wang, Yi; Sui, Yuxiu; Yao, Jingjing; Zhang, Chen-Yuan; Cheung, Eric F C; Chan, Raymond C K

2016-12-01

Multitasking refers to the ability to organize assorted tasks efficiently in a short period of time, which plays an important role in daily life. However, the structural neural correlates of multitasking performance remain unclear. The present study aimed at exploring the brain regions associated with multitasking performance using global correlation analysis. Twenty-six healthy participants first underwent structural brain scans and then performed the modified Six Element Test, which required participants to attempt six subtasks in 10 min while obeying a specific rule. Voxel-based morphometry of the whole brain was used to detect the structural correlates of multitasking ability. Grey matter volume of the anterior cingulate cortex (ACC) was positively correlated with the overall performance and time monitoring in multitasking. In addition, white matter volume of the anterior thalamic radiation (ATR) was also positively correlated with time monitoring during multitasking. Other related brain regions associated with multitasking included the superior frontal gyrus, the inferior occipital gyrus, the lingual gyrus, and the inferior longitudinal fasciculus. No significant correlation was found between grey matter volume of the prefrontal cortex (Brodmann Area 10) and multitasking performance. Using a global correlation analysis to examine various aspects of multitasking performance, this study provided new insights into the structural neural correlates of multitasking ability. In particular, the ACC was identified as an important brain region that played both a general and a specific time-monitoring role in multitasking, extending the role of the ACC from lesioned populations to healthy populations. The present findings also support the view that the ATR may influence multitasking performance by affecting time-monitoring abilities. © 2016 The Institute of Psychology, Chinese Academy of Sciences and John Wiley & Sons Australia, Ltd.

Neural Correlates of Post-Conventional Moral Reasoning: A Voxel-Based Morphometry Study

Science.gov (United States)

Prehn, Kristin; Korczykowski, Marc; Rao, Hengyi; Fang, Zhuo; Detre, John A.; Robertson, Diana C.

2015-01-01

Going back to Kohlberg, moral development research affirms that people progress through different stages of moral reasoning as cognitive abilities mature. Individuals at a lower level of moral reasoning judge moral issues mainly based on self-interest (personal interests schema) or based on adherence to laws and rules (maintaining norms schema), whereas individuals at the post-conventional level judge moral issues based on deeper principles and shared ideals. However, the extent to which moral development is reflected in structural brain architecture remains unknown. To investigate this question, we used voxel-based morphometry and examined the brain structure in a sample of 67 Master of Business Administration (MBA) students. Subjects completed the Defining Issues Test (DIT-2) which measures moral development in terms of cognitive schema preference. Results demonstrate that subjects at the post-conventional level of moral reasoning were characterized by increased gray matter volume in the ventromedial prefrontal cortex and subgenual anterior cingulate cortex, compared with subjects at a lower level of moral reasoning. Our findings support an important role for both cognitive and emotional processes in moral reasoning and provide first evidence for individual differences in brain structure according to the stages of moral reasoning first proposed by Kohlberg decades ago. PMID:26039547

Neural correlates of post-conventional moral reasoning: a voxel-based morphometry study.

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Kristin Prehn

Full Text Available Going back to Kohlberg, moral development research affirms that people progress through different stages of moral reasoning as cognitive abilities mature. Individuals at a lower level of moral reasoning judge moral issues mainly based on self-interest (personal interests schema or based on adherence to laws and rules (maintaining norms schema, whereas individuals at the post-conventional level judge moral issues based on deeper principles and shared ideals. However, the extent to which moral development is reflected in structural brain architecture remains unknown. To investigate this question, we used voxel-based morphometry and examined the brain structure in a sample of 67 Master of Business Administration (MBA students. Subjects completed the Defining Issues Test (DIT-2 which measures moral development in terms of cognitive schema preference. Results demonstrate that subjects at the post-conventional level of moral reasoning were characterized by increased gray matter volume in the ventromedial prefrontal cortex and subgenual anterior cingulate cortex, compared with subjects at a lower level of moral reasoning. Our findings support an important role for both cognitive and emotional processes in moral reasoning and provide first evidence for individual differences in brain structure according to the stages of moral reasoning first proposed by Kohlberg decades ago.

Neural correlates of post-conventional moral reasoning: a voxel-based morphometry study.

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Prehn, Kristin; Korczykowski, Marc; Rao, Hengyi; Fang, Zhuo; Detre, John A; Robertson, Diana C

2015-01-01

Going back to Kohlberg, moral development research affirms that people progress through different stages of moral reasoning as cognitive abilities mature. Individuals at a lower level of moral reasoning judge moral issues mainly based on self-interest (personal interests schema) or based on adherence to laws and rules (maintaining norms schema), whereas individuals at the post-conventional level judge moral issues based on deeper principles and shared ideals. However, the extent to which moral development is reflected in structural brain architecture remains unknown. To investigate this question, we used voxel-based morphometry and examined the brain structure in a sample of 67 Master of Business Administration (MBA) students. Subjects completed the Defining Issues Test (DIT-2) which measures moral development in terms of cognitive schema preference. Results demonstrate that subjects at the post-conventional level of moral reasoning were characterized by increased gray matter volume in the ventromedial prefrontal cortex and subgenual anterior cingulate cortex, compared with subjects at a lower level of moral reasoning. Our findings support an important role for both cognitive and emotional processes in moral reasoning and provide first evidence for individual differences in brain structure according to the stages of moral reasoning first proposed by Kohlberg decades ago.

Shifting from region of interest (ROI) to voxel-based analysis in human brain mapping

International Nuclear Information System (INIS)

Astrakas, Loukas G.; Argyropoulou, Maria I.

2010-01-01

Current clinical studies involve multidimensional high-resolution images containing an overwhelming amount of structural and functional information. The analysis of such a wealth of information is becoming increasingly difficult yet necessary in order to improve diagnosis, treatment and healthcare. Voxel-wise analysis is a class of modern methods of image processing in the medical field with increased popularity. It has replaced manual region of interest (ROI) analysis and has provided tools to make statistical inferences at voxel level. The introduction of voxel-based analysis software in all modern commercial scanners allows clinical use of these techniques. This review will explain the main principles, advantages and disadvantages behind these methods of image analysis. (orig.)

Regional brain structural abnormality in ischemic stroke patients: a voxel-based morphometry study

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Ping Wu

2016-01-01

Full Text Available Our previous study used regional homogeneity analysis and found that activity in some brain areas of patients with ischemic stroke changed significantly. In the current study, we examined structural changes in these brain regions by taking structural magnetic resonance imaging scans of 11 ischemic stroke patients and 15 healthy participants, and analyzing the data using voxel-based morphometry. Compared with healthy participants, patients exhibited higher gray matter density in the left inferior occipital gyrus and right anterior white matter tract. In contrast, gray matter density in the right cerebellum, left precentral gyrus, right middle frontal gyrus, and left middle temporal gyrus was less in ischemic stroke patients. The changes of gray matter density in the middle frontal gyrus were negatively associated with the clinical rating scales of the Fugl-Meyer Motor Assessment (r = -0.609, P = 0.047 and the left middle temporal gyrus was negatively correlated with the clinical rating scales of the nervous functional deficiency scale (r = -0.737, P = 0.010. Our findings can objectively identify the functional abnormality in some brain regions of ischemic stroke patients.

Gait Analysis Using Wearable Sensors

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Hutian Feng

2012-02-01

Full Text Available Gait analysis using wearable sensors is an inexpensive, convenient, and efficient manner of providing useful information for multiple health-related applications. As a clinical tool applied in the rehabilitation and diagnosis of medical conditions and sport activities, gait analysis using wearable sensors shows great prospects. The current paper reviews available wearable sensors and ambulatory gait analysis methods based on the various wearable sensors. After an introduction of the gait phases, the principles and features of wearable sensors used in gait analysis are provided. The gait analysis methods based on wearable sensors is divided into gait kinematics, gait kinetics, and electromyography. Studies on the current methods are reviewed, and applications in sports, rehabilitation, and clinical diagnosis are summarized separately. With the development of sensor technology and the analysis method, gait analysis using wearable sensors is expected to play an increasingly important role in clinical applications.

Gait Analysis Using Wearable Sensors

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Tao, Weijun; Liu, Tao; Zheng, Rencheng; Feng, Hutian

2012-01-01

Gait analysis using wearable sensors is an inexpensive, convenient, and efficient manner of providing useful information for multiple health-related applications. As a clinical tool applied in the rehabilitation and diagnosis of medical conditions and sport activities, gait analysis using wearable sensors shows great prospects. The current paper reviews available wearable sensors and ambulatory gait analysis methods based on the various wearable sensors. After an introduction of the gait phases, the principles and features of wearable sensors used in gait analysis are provided. The gait analysis methods based on wearable sensors is divided into gait kinematics, gait kinetics, and electromyography. Studies on the current methods are reviewed, and applications in sports, rehabilitation, and clinical diagnosis are summarized separately. With the development of sensor technology and the analysis method, gait analysis using wearable sensors is expected to play an increasingly important role in clinical applications. PMID:22438763

Vision-based gait impairment analysis for aided diagnosis.

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Ortells, Javier; Herrero-Ezquerro, María Trinidad; Mollineda, Ramón A

2018-02-12

Gait is a firsthand reflection of health condition. This belief has inspired recent research efforts to automate the analysis of pathological gait, in order to assist physicians in decision-making. However, most of these efforts rely on gait descriptions which are difficult to understand by humans, or on sensing technologies hardly available in ambulatory services. This paper proposes a number of semantic and normalized gait features computed from a single video acquired by a low-cost sensor. Far from being conventional spatio-temporal descriptors, features are aimed at quantifying gait impairment, such as gait asymmetry from several perspectives or falling risk. They were designed to be invariant to frame rate and image size, allowing cross-platform comparisons. Experiments were formulated in terms of two databases. A well-known general-purpose gait dataset is used to establish normal references for features, while a new database, introduced in this work, provides samples under eight different walking styles: one normal and seven impaired patterns. A number of statistical studies were carried out to prove the sensitivity of features at measuring the expected pathologies, providing enough evidence about their accuracy. Graphical Abstract Graphical abstract reflecting main contributions of the manuscript: at the top, a robust, semantic and easy-to-interpret feature set to describe impaired gait patterns; at the bottom, a new dataset consisting of video-recordings of a number of volunteers simulating different patterns of pathological gait, where features were statistically assessed.

2.5D Multi-View Gait Recognition Based on Point Cloud Registration

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Tang, Jin; Luo, Jian; Tjahjadi, Tardi; Gao, Yan

2014-01-01

This paper presents a method for modeling a 2.5-dimensional (2.5D) human body and extracting the gait features for identifying the human subject. To achieve view-invariant gait recognition, a multi-view synthesizing method based on point cloud registration (MVSM) to generate multi-view training galleries is proposed. The concept of a density and curvature-based Color Gait Curvature Image is introduced to map 2.5D data onto a 2D space to enable data dimension reduction by discrete cosine transform and 2D principle component analysis. Gait recognition is achieved via a 2.5D view-invariant gait recognition method based on point cloud registration. Experimental results on the in-house database captured by a Microsoft Kinect camera show a significant performance gain when using MVSM. PMID:24686727

Object-action dissociation: A voxel-based lesion-symptom mapping study on 102 patients after glioma removal

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Alberto Pisoni

Full Text Available Data concerning the neural basis of noun and verb processing are inconsistent. Some authors assume that action-verb processing is based on frontal areas while nouns processing relies on temporal regions; others argue that the circuits processing verbs and nouns are closely interconnected in a predominantly left-lateralized fronto-temporal-parietal network; yet, other researchers consider that the primary motor cortex plays a crucial role in processing action verbs. In the present study, one hundred and two patients with a tumour either in the right or left hemisphere were submitted to picture naming of objects and actions before and after surgery. To test the effect of specific brain regions in object and action naming, patients' lesions were mapped and voxel-lesion-symptom mapping (VLSM was computed. Behavioural results showed that left-brain damaged patients were significantly more impaired than right brain-damaged patients. The VLSM showed that these two grammatical classes are segregated in the left hemisphere. In particular, scores in naming of objects correlated with damage to the anterior temporal region, while scores in naming of actions correlated with lesions in the parietal areas and in the posterior temporal cortex. In addition, VLSM analyses carried out on non-linguistic tasks were not significant, confirming that the regions associated with deficits in object and action naming were not generally engaged in all cognitive tasks. Finally, the involvement of subcortical pathways was investigated and the inferior longitudinal fasciculus proved to play a role in object naming, while no specific bundle was identified for actions. Keywords: Object action dissociation, Temporal lesion, Frontal lesion, Voxel-based lesion symptom mapping

Whole-brain voxel-based morphometry of white matter in mild cognitive impairment

International Nuclear Information System (INIS)

Wang Zhiqun; Guo Xiaojuan; Qi Zhigang; Yao Li; Li Kuncheng

2010-01-01

Purpose: The purpose of this study was to analyze whole-brain white matter changes in mild cognitive impairment (MCI). Materials and methods: We studied 14 patients with MCI and 14 age- and sex-matched healthy control subjects using voxel-based morphometry (VBM) on T1-weighted 3D datasets. The data were collected on a 3T MR system and analyzed by SPM2 to generate white matter volume maps. Results: Voxel-based morphometry revealed diffusively reduced white matter in MCI prominently including the bilateral temporal gyrus, the right anterior cingulate, the bilateral superior and medial frontal gyrus and right parietal angular gyrus. White matter reduction was more prominent in anterior regions than that in posterior regions. Conclusion: Whole-brain white matter reduction in MCI patients detected with VBM has special distribution which is in line with the white matter pathology of MCI.

Whole-brain voxel-based morphometry of white matter in mild cognitive impairment

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Wang Zhiqun [Department of Radiology, Xuanwu Hospital of Capital Medical University, 100053, Beijing (China); Guo Xiaojuan [College of Information Science and Technology, Beijing Normal University, 100875, Beijing (China); National Key Laboratory for Cognitive Neuroscience and Learning, Beijing Normal University, 100875, Beijing (China); Qi Zhigang [Department of Radiology, Xuanwu Hospital of Capital Medical University, 100053, Beijing (China); Yao Li [College of Information Science and Technology, Beijing Normal University, 100875, Beijing (China); National Key Laboratory for Cognitive Neuroscience and Learning, Beijing Normal University, 100875, Beijing (China); Li Kuncheng, E-mail: likuncheng@xwh.ccmu.edu.c [Department of Radiology, Xuanwu Hospital of Capital Medical University, 100053, Beijing (China)

2010-08-15

Purpose: The purpose of this study was to analyze whole-brain white matter changes in mild cognitive impairment (MCI). Materials and methods: We studied 14 patients with MCI and 14 age- and sex-matched healthy control subjects using voxel-based morphometry (VBM) on T1-weighted 3D datasets. The data were collected on a 3T MR system and analyzed by SPM2 to generate white matter volume maps. Results: Voxel-based morphometry revealed diffusively reduced white matter in MCI prominently including the bilateral temporal gyrus, the right anterior cingulate, the bilateral superior and medial frontal gyrus and right parietal angular gyrus. White matter reduction was more prominent in anterior regions than that in posterior regions. Conclusion: Whole-brain white matter reduction in MCI patients detected with VBM has special distribution which is in line with the white matter pathology of MCI.

DeepGait: A Learning Deep Convolutional Representation for View-Invariant Gait Recognition Using Joint Bayesian

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Chao Li

2017-02-01

Full Text Available Human gait, as a soft biometric, helps to recognize people through their walking. To further improve the recognition performance, we propose a novel video sensor-based gait representation, DeepGait, using deep convolutional features and introduce Joint Bayesian to model view variance. DeepGait is generated by using a pre-trained “very deep” network “D-Net” (VGG-D without any fine-tuning. For non-view setting, DeepGait outperforms hand-crafted representations (e.g., Gait Energy Image, Frequency-Domain Feature and Gait Flow Image, etc.. Furthermore, for cross-view setting, 256-dimensional DeepGait after PCA significantly outperforms the state-of-the-art methods on the OU-ISR large population (OULP dataset. The OULP dataset, which includes 4007 subjects, makes our result reliable in a statistically reliable way.

A voxel-based investigation for MRI-only radiotherapy of the brain using ultra short echo times

DEFF Research Database (Denmark)

Edmund, Jens Morgenthaler; Kjer, Hans Martin; Van Leemput, Koen

2014-01-01

including or excluding additional spatial information. Approach 3 used a statistical regression correlating MRI voxels with their corresponding CT voxels. A similar photon and proton treatment plan was generated for a target positioned between the nasal cavity and the brainstem for all patients. The CT...... receiving cranial irradiation, each containing a co-registered MRI and CT scan, were included. An ultra short echo time MRI sequence for bone visualization was used. Six methods were investigated for three popular types of voxel-based approaches; (1) threshold-based segmentation, (2) Bayesian segmentation...... significantly better than the threshold and Bayesian segmentation methods (excluding spatial information). All methods agreed significantly better with CT than a reference water MRI comparison. The mean dosimetric deviation for photons and protons compared to the CT was about 2% and highest in the gradient dose...

Accelerometry-based gait analysis, an additional objective approach to screen subjects at risk for falling.

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Senden, R; Savelberg, H H C M; Grimm, B; Heyligers, I C; Meijer, K

2012-06-01

This study investigated whether the Tinetti scale, as a subjective measure for fall risk, is associated with objectively measured gait characteristics. It is studied whether gait parameters are different for groups that are stratified for fall risk using the Tinetti scale. Moreover, the discriminative power of gait parameters to classify elderly according to the Tinetti scale is investigated. Gait of 50 elderly with a Tinneti>24 and 50 elderly with a Tinetti≤24 was analyzed using acceleration-based gait analysis. Validated algorithms were used to derive spatio-temporal gait parameters, harmonic ratio, inter-stride amplitude variability and root mean square (RMS) from the accelerometer data. Clear differences in gait were found between the groups. All gait parameters correlated with the Tinetti scale (r-range: 0.20-0.73). Only walking speed, step length and RMS showed moderate to strong correlations and high discriminative power to classify elderly according to the Tinetti scale. It is concluded that subtle gait changes that have previously been related to fall risk are not captured by the subjective assessment. It is therefore worthwhile to include objective gait assessment in fall risk screening. Copyright © 2012 Elsevier B.V. All rights reserved.

A voxel-based finite element model for the prediction of bladder deformation

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Xiangfei, Chai; Herk, Marcel van; Hulshof, Maarten C. C. M.; Bel, Arjan [Radiation Oncology Department, Academic Medical Center, University of Amsterdam, 1105 AZ Amsterdam (Netherlands); Radiation Oncology Department, Netherlands Cancer Institute, 1066 CX Amsterdam (Netherlands); Radiation Oncology Department, Academic Medical Center, University of Amsterdam, 1105 AZ Amsterdam (Netherlands)

2012-01-15

Purpose: A finite element (FE) bladder model was previously developed to predict bladder deformation caused by bladder filling change. However, two factors prevent a wide application of FE models: (1) the labor required to construct a FE model with high quality mesh and (2) long computation time needed to construct the FE model and solve the FE equations. In this work, we address these issues by constructing a low-resolution voxel-based FE bladder model directly from the binary segmentation images and compare the accuracy and computational efficiency of the voxel-based model used to simulate bladder deformation with those of a classical FE model with a tetrahedral mesh. Methods: For ten healthy volunteers, a series of MRI scans of the pelvic region was recorded at regular intervals of 10 min over 1 h. For this series of scans, the bladder volume gradually increased while rectal volume remained constant. All pelvic structures were defined from a reference image for each volunteer, including bladder wall, small bowel, prostate (male), uterus (female), rectum, pelvic bone, spine, and the rest of the body. Four separate FE models were constructed from these structures: one with a tetrahedral mesh (used in previous study), one with a uniform hexahedral mesh, one with a nonuniform hexahedral mesh, and one with a low-resolution nonuniform hexahedral mesh. Appropriate material properties were assigned to all structures and uniform pressure was applied to the inner bladder wall to simulate bladder deformation from urine inflow. Performance of the hexahedral meshes was evaluated against the performance of the standard tetrahedral mesh by comparing the accuracy of bladder shape prediction and computational efficiency. Results: FE model with a hexahedral mesh can be quickly and automatically constructed. No substantial differences were observed between the simulation results of the tetrahedral mesh and hexahedral meshes (<1% difference in mean dice similarity coefficient to

A voxel-based finite element model for the prediction of bladder deformation

International Nuclear Information System (INIS)

Chai Xiangfei; Herk, Marcel van; Hulshof, Maarten C. C. M.; Bel, Arjan

2012-01-01

Purpose: A finite element (FE) bladder model was previously developed to predict bladder deformation caused by bladder filling change. However, two factors prevent a wide application of FE models: (1) the labor required to construct a FE model with high quality mesh and (2) long computation time needed to construct the FE model and solve the FE equations. In this work, we address these issues by constructing a low-resolution voxel-based FE bladder model directly from the binary segmentation images and compare the accuracy and computational efficiency of the voxel-based model used to simulate bladder deformation with those of a classical FE model with a tetrahedral mesh. Methods: For ten healthy volunteers, a series of MRI scans of the pelvic region was recorded at regular intervals of 10 min over 1 h. For this series of scans, the bladder volume gradually increased while rectal volume remained constant. All pelvic structures were defined from a reference image for each volunteer, including bladder wall, small bowel, prostate (male), uterus (female), rectum, pelvic bone, spine, and the rest of the body. Four separate FE models were constructed from these structures: one with a tetrahedral mesh (used in previous study), one with a uniform hexahedral mesh, one with a nonuniform hexahedral mesh, and one with a low-resolution nonuniform hexahedral mesh. Appropriate material properties were assigned to all structures and uniform pressure was applied to the inner bladder wall to simulate bladder deformation from urine inflow. Performance of the hexahedral meshes was evaluated against the performance of the standard tetrahedral mesh by comparing the accuracy of bladder shape prediction and computational efficiency. Results: FE model with a hexahedral mesh can be quickly and automatically constructed. No substantial differences were observed between the simulation results of the tetrahedral mesh and hexahedral meshes (<1% difference in mean dice similarity coefficient to

Brain structural changes and their correlation with vascular disease in type 2 diabetes mellitus patients: a voxel-based morphometric study

OpenAIRE

Wang, Chunxia; Fu, Kailiang; Liu, Huaijun; Xing, Fei; Zhang, Songyun

2014-01-01

Voxel-based morphometry has been used in the study of alterations in brain structure in type 1 diabetes mellitus patients. These changes are associated with clinical indices. The age at onset, pathogenesis, and treatment of type 1 diabetes mellitus are different from those for type 2 diabetes mellitus. Thus, type 1 and type 2 diabetes mellitus may have different impacts on brain structure. Only a few studies of the alterations in brain structure in type 2 diabetes mellitus patients using voxe...

Predicting drought propagation within peat layers using a three dimensionally explicit voxel based model

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Condro, A. A.; Pawitan, H.; Risdiyanto, I.

2018-05-01

Peatlands are very vulnerable to widespread fires during dry seasons, due to availability of aboveground fuel biomass on the surface and belowground fuel biomass on the sub-surface. Hence, understanding drought propagation occurring within peat layers is crucial with regards to disaster mitigation activities on peatlands. Using a three dimensionally explicit voxel-based model of peatland hydrology, this study predicted drought propagation time lags into sub-surface peat layers after drought events occurrence on the surface of about 1 month during La-Nina and 2.5 months during El-Nino. The study was carried out on a high-conservation-value area of oil palm plantation in West Kalimantan. Validity of the model was evaluated and its applicability for disaster mitigation was discussed. The animations of simulated voxels are available at: goo.gl/HDRMYN (El-Nino 2015 episode) and goo.gl/g1sXPl (La-Nina 2016 episode). The model is available at: goo.gl/RiuMQz.

Gait Analysis Using Computer Vision Based on Cloud Platform and Mobile Device

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Mario Nieto-Hidalgo

2018-01-01

Full Text Available Frailty and senility are syndromes that affect elderly people. The ageing process involves a decay of cognitive and motor functions which often produce an impact on the quality of life of elderly people. Some studies have linked this deterioration of cognitive and motor function to gait patterns. Thus, gait analysis can be a powerful tool to assess frailty and senility syndromes. In this paper, we propose a vision-based gait analysis approach performed on a smartphone with cloud computing assistance. Gait sequences recorded by a smartphone camera are processed by the smartphone itself to obtain spatiotemporal features. These features are uploaded onto the cloud in order to analyse and compare them to a stored database to render a diagnostic. The feature extraction method presented can work with both frontal and sagittal gait sequences although the sagittal view provides a better classification since an accuracy of 95% can be obtained.

Different brain structures associated with artistic and scientific creativity: a voxel-based morphometry study.

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Shi, Baoguo; Cao, Xiaoqing; Chen, Qunlin; Zhuang, Kaixiang; Qiu, Jiang

2017-02-21

Creativity is the ability to produce original and valuable ideas or behaviors. In real life, artistic and scientific creativity promoted the development of human civilization; however, to date, no studies have systematically investigated differences in the brain structures responsible for artistic and scientific creativity in a large sample. Using voxel-based morphometry (VBM), this study identified differences in regional gray matter volume (GMV) across the brain between artistic and scientific creativity (assessed by the Creative Achievement Questionnaire) in 356 young, healthy subjects. The results showed that artistic creativity was significantly negatively associated with the regional GMV of the supplementary motor area (SMA) and anterior cingulate cortex (ACC). In contrast, scientific creativity was significantly positively correlated with the regional GMV of the left middle frontal gyrus (MFG) and left inferior occipital gyrus (IOG). Overall, artistic creativity was associated with the salience network (SN), whereas scientific creativity was associated with the executive attention network and semantic processing. These results may provide an effective marker that can be used to predict and evaluate individuals' creative performance in the fields of science and art.

Gait and footwear in children and adolescents with Charcot-Marie-Tooth disease: A cross-sectional, case-controlled study.

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Kennedy, Rachel A; McGinley, Jennifer L; Paterson, Kade L; Ryan, Monique M; Carroll, Kate

2018-05-01

Children with Charcot-Marie-Tooth disease (CMT) report problems with gait and footwear. We evaluated differences in spatio-temporal gait variables and gait variability between children with CMT and typically developing (TD) children, and investigated the effect of footwear upon gait. A cross-sectional study of 30 children with CMT and 30 age- and gender-matched TD children aged 4-18 years. Gait was assessed at self-selected speed on an electronic walkway while barefoot and in two types of the child's own footwear; optimal (e.g., athletic-type runners) and suboptimal (e.g., flip-flops). Children with CMT walked more slowly (mean (SD) -13.81 (3.61) cm/s), with shorter steps (-6.28 (1.37) cm), wider base of support (+2.47 (0.66) cm; all p footwear than suboptimal (-7.55 (1.31) cm/s) and barefoot (-7.42 (1.07) cm/sec; both p footwear was more variable compared to barefoot and optimal footwear. Greater base of support variability and reduced balance was moderately correlated for both groups (CMT and TD). Gait is slower with shorter, wider steps and greater base of support variability in children with CMT. Poor balance is associated with greater base of support gait variability. Suboptimal footwear negatively affects gait in all children (CMT and TD), which has clinical implications for children and adolescents with CMT who have weaker feet and ankles, and poor balance. Copyright © 2018 Elsevier B.V. All rights reserved.

Measuring the effect of treatment on gait quality in children with cerebral palsy – a retrospective study

DEFF Research Database (Denmark)

Larsen, Anders Holsgaard; Skov Sørensen, Rasmus; Jensen, Carsten

and subsequently, as a follow-up. Thus, the effect of treatment on gait quality in children with CP may be quantified. Purpose of study: In a retrospective study we investigated the effect of treatment on gait quality (measured by GDI) in children with CP. Materials and Methods: Data from children (...Background: Gait Deviation Index (GDI) describes the overall gait quality and summarizes it into a single score based upon three- dimensional gait analysis (3DGA). In the Region of Southern Denmark, children with cerebral palsy (CP) are referred to 3DGA if surgical intervention is considered......) diagnosed with CP and referred to 3DGA (either as a diagnostic instrument or for the purpose of follow- up) was extracted from a local database for the year 2012. The GDI score was calculated for each child and limb and used for further analysis. Results: 29 children with follow-up analysis were referred...

A voxel-based multiscale model to simulate the radiation response of hypoxic tumors.

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Espinoza, I; Peschke, P; Karger, C P

2015-01-01

In radiotherapy, it is important to predict the response of tumors to irradiation prior to the treatment. This is especially important for hypoxic tumors, which are known to be highly radioresistant. Mathematical modeling based on the dose distribution, biological parameters, and medical images may help to improve this prediction and to optimize the treatment plan. A voxel-based multiscale tumor response model for simulating the radiation response of hypoxic tumors was developed. It considers viable and dead tumor cells, capillary and normal cells, as well as the most relevant biological processes such as (i) proliferation of tumor cells, (ii) hypoxia-induced angiogenesis, (iii) spatial exchange of cells leading to tumor growth, (iv) oxygen-dependent cell survival after irradiation, (v) resorption of dead cells, and (vi) spatial exchange of cells leading to tumor shrinkage. Oxygenation is described on a microscopic scale using a previously published tumor oxygenation model, which calculates the oxygen distribution for each voxel using the vascular fraction as the most important input parameter. To demonstrate the capabilities of the model, the dependence of the oxygen distribution on tumor growth and radiation-induced shrinkage is investigated. In addition, the impact of three different reoxygenation processes is compared and tumor control probability (TCP) curves for a squamous cells carcinoma of the head and neck (HNSSC) are simulated under normoxic and hypoxic conditions. The model describes the spatiotemporal behavior of the tumor on three different scales: (i) on the macroscopic scale, it describes tumor growth and shrinkage during radiation treatment, (ii) on a mesoscopic scale, it provides the cell density and vascular fraction for each voxel, and (iii) on the microscopic scale, the oxygen distribution may be obtained in terms of oxygen histograms. With increasing tumor size, the simulated tumors develop a hypoxic core. Within the model, tumor shrinkage was

A voxel-based multiscale model to simulate the radiation response of hypoxic tumors

International Nuclear Information System (INIS)

Espinoza, I.; Peschke, P.; Karger, C. P.

2015-01-01

Purpose: In radiotherapy, it is important to predict the response of tumors to irradiation prior to the treatment. This is especially important for hypoxic tumors, which are known to be highly radioresistant. Mathematical modeling based on the dose distribution, biological parameters, and medical images may help to improve this prediction and to optimize the treatment plan. Methods: A voxel-based multiscale tumor response model for simulating the radiation response of hypoxic tumors was developed. It considers viable and dead tumor cells, capillary and normal cells, as well as the most relevant biological processes such as (i) proliferation of tumor cells, (ii) hypoxia-induced angiogenesis, (iii) spatial exchange of cells leading to tumor growth, (iv) oxygen-dependent cell survival after irradiation, (v) resorption of dead cells, and (vi) spatial exchange of cells leading to tumor shrinkage. Oxygenation is described on a microscopic scale using a previously published tumor oxygenation model, which calculates the oxygen distribution for each voxel using the vascular fraction as the most important input parameter. To demonstrate the capabilities of the model, the dependence of the oxygen distribution on tumor growth and radiation-induced shrinkage is investigated. In addition, the impact of three different reoxygenation processes is compared and tumor control probability (TCP) curves for a squamous cells carcinoma of the head and neck (HNSSC) are simulated under normoxic and hypoxic conditions. Results: The model describes the spatiotemporal behavior of the tumor on three different scales: (i) on the macroscopic scale, it describes tumor growth and shrinkage during radiation treatment, (ii) on a mesoscopic scale, it provides the cell density and vascular fraction for each voxel, and (iii) on the microscopic scale, the oxygen distribution may be obtained in terms of oxygen histograms. With increasing tumor size, the simulated tumors develop a hypoxic core. Within the

A mechanized gait trainer for restoration of gait.

Science.gov (United States)

Hesse, S; Uhlenbrock, D

2000-01-01

The newly developed gait trainer allows wheel-chair-bound subjects the repetitive practice of a gait-like movement without overstressing therapists. The device simulates the phases of gait, supports the subjects according to their abilities, and controls the center of mass (CoM) in the vertical and horizontal directions. The patterns of sagittal lower limb joint kinematics and of muscle activation for a normal subject were similar when using the mechanized trainer and when walking on a treadmill. A non-ambulatory hemiparetic subject required little help from one therapist on the gait trainer, while two therapists were required to support treadmill walking. Gait movements on the trainer were highly symmetrical, impact free, and less spastic. The vertical displacement of the CoM was bi-phasic instead of mono-phasic during each gait cycle on the new device. Two cases of non-ambulatory patients, who regained their walking ability after 4 weeks of daily training on the gait trainer, are reported.

Association of Dual-Task Gait With Incident Dementia in Mild Cognitive Impairment: Results From the Gait and Brain Study.

Science.gov (United States)

Montero-Odasso, Manuel M; Sarquis-Adamson, Yanina; Speechley, Mark; Borrie, Michael J; Hachinski, Vladimir C; Wells, Jennie; Riccio, Patricia M; Schapira, Marcelo; Sejdic, Ervin; Camicioli, Richard M; Bartha, Robert; McIlroy, William E; Muir-Hunter, Susan

2017-07-01

Gait performance is affected by neurodegeneration in aging and has the potential to be used as a clinical marker for progression from mild cognitive impairment (MCI) to dementia. A dual-task gait test evaluating the cognitive-motor interface may predict dementia progression in older adults with MCI. To determine whether a dual-task gait test is associated with incident dementia in MCI. The Gait and Brain Study is an ongoing prospective cohort study of community-dwelling older adults that enrolled 112 older adults with MCI. Participants were followed up for 6 years, with biannual visits including neurologic, cognitive, and gait assessments. Data were collected from July 2007 to March 2016. Incident all-cause dementia was the main outcome measure, and single- and dual-task gait velocity and dual-task gait costs were the independent variables. A neuropsychological test battery was used to assess cognition. Gait velocity was recorded under single-task and 3 separate dual-task conditions using an electronic walkway. Dual-task gait cost was defined as the percentage change between single- and dual-task gait velocities: ([single-task gait velocity - dual-task gait velocity]/ single-task gait velocity) × 100. Cox proportional hazard models were used to estimate the association between risk of progression to dementia and the independent variables, adjusted for age, sex, education, comorbidities, and cognition. Among 112 study participants with MCI, mean (SD) age was 76.6 (6.9) years, 55 were women (49.1%), and 27 progressed to dementia (24.1%), with an incidence rate of 121 per 1000 person-years. Slow single-task gait velocity (gait cost while counting backward (HR, 3.79; 95% CI, 1.57-9.15; P = .003) and naming animals (HR, 2.41; 95% CI, 1.04-5.59; P = .04) were associated with dementia progression (incidence rate, 155 per 1000 person-years). The models remained robust after adjusting by baseline cognition except for dual-task gait cost when dichotomized. Dual

Strategies for improving the Voxel-based statistical analysis for animal PET studies: assessment of cerebral glucose metabolism in cat deafness model

International Nuclear Information System (INIS)

Kim, Jin Su; Lee, Jae Sung; Park, Min Hyun; Kang, Hye Jin; Im, Ki Chun; Moon, Dae Hyuk; Lim, Sang Moo; Oh, Seung Ha; Lee, Dong Soo

2007-01-01

In imaging studies of the human brain, voxel-based statistical analysis method was widely used, since these methods were originally developed for the analysis of the human brain data, they are not optimal for the animal brain data. The aim of this study is to optimize the procedures for the 3D voxel-based statistical analysis of cat FDG PET brain images. A microPET Focus 120 scanner was used. Eight cats underwent FDG PET scans twice before and after inducing the deafness. Only the brain and adjacent regions were extracted from each data set by manual masking. Individual PET image at normal and deaf state was realigned to each other to remove the confounding effects by the different spatial normalization parameters on the results of statistical analyses. Distance between the sampling points on the reference image and kernel size of Gaussian filter applied to the images before estimating the realignment parameters were adjusted to 0.5 mm and 2 mm. Both data was then spatial normalized onto study-specific cat brain template. Spatially normalized PET data were smoothed and voxel-based paired t-test was performed. Cerebral glucose metabolism decreased significantly after the loss of hearing capability in parietal lobes, postcentral gyri, STG, MTG, lTG, and IC at both hemisphere and left SC (FDR corrected P < 0.05, k=50). Cerebral glucose metabolism in deaf cats was found to be significantly higher than in controls in the right cingulate (FDR corrected P < 0.05, k=50). The ROI analysis also showed significant reduction of glucose metabolism in the same areas as in the SPM analysis, except for some regions (P < 0.05). Method for the voxel-based analysis of cat brain PET data was optimized for analysis of cat brain PET. This result was also confirmed by ROI analysis. The results obtained demonstrated the high localization accuracy and specificity of the developed method, and were found to be useful for examining cerebral glucose metabolism in a cat cortical deafness model

Strategies for improving the Voxel-based statistical analysis for animal PET studies: assessment of cerebral glucose metabolism in cat deafness model

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Kim, Jin Su; Lee, Jae Sung; Park, Min Hyun; Kang, Hye Jin; Im, Ki Chun; Moon, Dae Hyuk; Lim, Sang Moo; Oh, Seung Ha; Lee, Dong Soo [Seoul National Univ. College of Medicine, Seoul (Korea, Republic of)

2007-07-01

In imaging studies of the human brain, voxel-based statistical analysis method was widely used, since these methods were originally developed for the analysis of the human brain data, they are not optimal for the animal brain data. The aim of this study is to optimize the procedures for the 3D voxel-based statistical analysis of cat FDG PET brain images. A microPET Focus 120 scanner was used. Eight cats underwent FDG PET scans twice before and after inducing the deafness. Only the brain and adjacent regions were extracted from each data set by manual masking. Individual PET image at normal and deaf state was realigned to each other to remove the confounding effects by the different spatial normalization parameters on the results of statistical analyses. Distance between the sampling points on the reference image and kernel size of Gaussian filter applied to the images before estimating the realignment parameters were adjusted to 0.5 mm and 2 mm. Both data was then spatial normalized onto study-specific cat brain template. Spatially normalized PET data were smoothed and voxel-based paired t-test was performed. Cerebral glucose metabolism decreased significantly after the loss of hearing capability in parietal lobes, postcentral gyri, STG, MTG, lTG, and IC at both hemisphere and left SC (FDR corrected P < 0.05, k=50). Cerebral glucose metabolism in deaf cats was found to be significantly higher than in controls in the right cingulate (FDR corrected P < 0.05, k=50). The ROI analysis also showed significant reduction of glucose metabolism in the same areas as in the SPM analysis, except for some regions (P < 0.05). Method for the voxel-based analysis of cat brain PET data was optimized for analysis of cat brain PET. This result was also confirmed by ROI analysis. The results obtained demonstrated the high localization accuracy and specificity of the developed method, and were found to be useful for examining cerebral glucose metabolism in a cat cortical deafness model.

A GPU-based Monte Carlo dose calculation code for photon transport in a voxel phantom

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Bellezzo, M.; Do Nascimento, E.; Yoriyaz, H., E-mail: mbellezzo@gmail.br [Instituto de Pesquisas Energeticas e Nucleares / CNEN, Av. Lineu Prestes 2242, Cidade Universitaria, 05508-000 Sao Paulo (Brazil)

2014-08-15

As the most accurate method to estimate absorbed dose in radiotherapy, Monte Carlo method has been widely used in radiotherapy treatment planning. Nevertheless, its efficiency can be improved for clinical routine applications. In this paper, we present the CUBMC code, a GPU-based Mc photon transport algorithm for dose calculation under the Compute Unified Device Architecture platform. The simulation of physical events is based on the algorithm used in Penelope, and the cross section table used is the one generated by the Material routine, als present in Penelope code. Photons are transported in voxel-based geometries with different compositions. To demonstrate the capabilities of the algorithm developed in the present work four 128 x 128 x 128 voxel phantoms have been considered. One of them is composed by a homogeneous water-based media, the second is composed by bone, the third is composed by lung and the fourth is composed by a heterogeneous bone and vacuum geometry. Simulations were done considering a 6 MeV monoenergetic photon point source. There are two distinct approaches that were used for transport simulation. The first of them forces the photon to stop at every voxel frontier, the second one is the Woodcock method, where the photon stop in the frontier will be considered depending on the material changing across the photon travel line. Dose calculations using these methods are compared for validation with Penelope and MCNP5 codes. Speed-up factors are compared using a NVidia GTX 560-Ti GPU card against a 2.27 GHz Intel Xeon CPU processor. (Author)

A GPU-based Monte Carlo dose calculation code for photon transport in a voxel phantom

International Nuclear Information System (INIS)

Bellezzo, M.; Do Nascimento, E.; Yoriyaz, H.

2014-08-01

As the most accurate method to estimate absorbed dose in radiotherapy, Monte Carlo method has been widely used in radiotherapy treatment planning. Nevertheless, its efficiency can be improved for clinical routine applications. In this paper, we present the CUBMC code, a GPU-based Mc photon transport algorithm for dose calculation under the Compute Unified Device Architecture platform. The simulation of physical events is based on the algorithm used in Penelope, and the cross section table used is the one generated by the Material routine, als present in Penelope code. Photons are transported in voxel-based geometries with different compositions. To demonstrate the capabilities of the algorithm developed in the present work four 128 x 128 x 128 voxel phantoms have been considered. One of them is composed by a homogeneous water-based media, the second is composed by bone, the third is composed by lung and the fourth is composed by a heterogeneous bone and vacuum geometry. Simulations were done considering a 6 MeV monoenergetic photon point source. There are two distinct approaches that were used for transport simulation. The first of them forces the photon to stop at every voxel frontier, the second one is the Woodcock method, where the photon stop in the frontier will be considered depending on the material changing across the photon travel line. Dose calculations using these methods are compared for validation with Penelope and MCNP5 codes. Speed-up factors are compared using a NVidia GTX 560-Ti GPU card against a 2.27 GHz Intel Xeon CPU processor. (Author)

Detecting gait abnormalities after concussion or mild traumatic brain injury: A systematic review of single-task, dual-task, and complex gait.

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Fino, Peter C; Parrington, Lucy; Pitt, Will; Martini, Douglas N; Chesnutt, James C; Chou, Li-Shan; King, Laurie A

2018-05-01

While a growing number of studies have investigated the effects of concussion or mild traumatic brain injury (mTBI) on gait, many studies use different experimental paradigms and outcome measures. The path for translating experimental studies for objective clinical assessments of gait is unclear. This review asked 2 questions: 1) is gait abnormal after concussion/mTBI, and 2) what gait paradigms (single-task, dual-task, complex gait) detect abnormalities after concussion. Data sources included MEDLINE/PubMed, Scopus, Web of Science, and Cumulative Index to Nursing and Allied Health Literature (CINAHL) accessed on March 14, 2017. Original research articles reporting gait outcomes in people with concussion or mTBI were included. Studies of moderate, severe, or unspecified TBI, and studies without a comparator were excluded. After screening 233 articles, 38 studies were included and assigned to one or more sections based on the protocol and reported outcomes. Twenty-six articles reported single-task simple gait outcomes, 24 reported dual-task simple gait outcomes, 21 reported single-task complex gait outcomes, and 10 reported dual-task complex gait outcomes. Overall, this review provides evidence for two conclusions: 1) gait is abnormal acutely after concussion/mTBI but generally resolves over time; and 2) the inconsistency of findings, small sample sizes, and small number of studies examining homogenous measures at the same time-period post-concussion highlight the need for replication across independent populations and investigators. Future research should concentrate on dual-task and complex gait tasks, as they showed promise for detecting abnormal locomotor function outside of the acute timeframe. Additionally, studies should provide detailed demographic and clinical characteristics to enable more refined comparisons across studies. Copyright © 2018 Elsevier B.V. All rights reserved.

Comparative study of SVM methods combined with voxel selection for object category classification on fMRI data.

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Song, Sutao; Zhan, Zhichao; Long, Zhiying; Zhang, Jiacai; Yao, Li

2011-02-16

Support vector machine (SVM) has been widely used as accurate and reliable method to decipher brain patterns from functional MRI (fMRI) data. Previous studies have not found a clear benefit for non-linear (polynomial kernel) SVM versus linear one. Here, a more effective non-linear SVM using radial basis function (RBF) kernel is compared with linear SVM. Different from traditional studies which focused either merely on the evaluation of different types of SVM or the voxel selection methods, we aimed to investigate the overall performance of linear and RBF SVM for fMRI classification together with voxel selection schemes on classification accuracy and time-consuming. Six different voxel selection methods were employed to decide which voxels of fMRI data would be included in SVM classifiers with linear and RBF kernels in classifying 4-category objects. Then the overall performances of voxel selection and classification methods were compared. Results showed that: (1) Voxel selection had an important impact on the classification accuracy of the classifiers: in a relative low dimensional feature space, RBF SVM outperformed linear SVM significantly; in a relative high dimensional space, linear SVM performed better than its counterpart; (2) Considering the classification accuracy and time-consuming holistically, linear SVM with relative more voxels as features and RBF SVM with small set of voxels (after PCA) could achieve the better accuracy and cost shorter time. The present work provides the first empirical result of linear and RBF SVM in classification of fMRI data, combined with voxel selection methods. Based on the findings, if only classification accuracy was concerned, RBF SVM with appropriate small voxels and linear SVM with relative more voxels were two suggested solutions; if users concerned more about the computational time, RBF SVM with relative small set of voxels when part of the principal components were kept as features was a better choice.

Treadmill training with partial body weight support and an electromechanical gait trainer for restoration of gait in subacute stroke patients: a randomized crossover study.

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Werner, C; Von Frankenberg, S; Treig, T; Konrad, M; Hesse, S

2002-12-01

The purpose of this study was to compare treadmill and electromechanical gait trainer therapy in subacute, nonambulatory stroke survivors. The gait trainer was designed to provide nonambulatory subjects the repetitive practice of a gait-like movement without overexerting therapists. This was a randomized, controlled study with a crossover design following an A-B-A versus a B-A-B pattern. A consisted of 2 weeks of gait trainer therapy, and B consisted of 2 weeks of treadmill therapy. Thirty nonambulatory hemiparetic patients, 4 to 12 weeks after stroke, were randomly assigned to 1 of the 2 groups receiving locomotor therapy every workday for 15 to 20 minutes for 6 weeks. Weekly gait ability (functional ambulation category [FAC]), gait velocity, and the required physical assistance during both kinds of locomotor therapy were the primary outcome measures, and other motor functions (Rivermead motor assessment score) and ankle spasticity (modified Ashworth score) were the secondary outcome measures. Follow-up occurred 6 months later. The groups did not differ at study onset with respect to the clinical characteristics and effector variables. During treatment, the FAC, gait velocity, and Rivermead scores improved in both groups, and ankle spasticity did not change. Median FAC level was 4 (3 to 4) in group A compared with 3 (2 to 3) in group B at the end of treatment (P=0.018), but the difference at 6-month follow up was not significant. The therapeutic effort was less on the gait trainer, with 1 instead of 2 therapists assisting the patient at study onset. All but seven patients preferred the gait trainer. The newly developed gait trainer was at least as effective as treadmill therapy with partial body weight support while requiring less input from the therapist. Further studies are warranted.

Motor imagery group practice for gait rehabilitation in individuals with post-stroke hemiparesis: a pilot study.

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Dickstein, Ruth; Levy, Sandra; Shefi, Sara; Holtzman, Sarit; Peleg, Sara; Vatine, Jean-Jacques

2014-01-01

Stroke is the leading cause of adult disability, with walking impairment being a devastating indicator of chronic post-stroke hemiparesis. Limited resources exist for individual treatments; therefore, the delivery of safe group exercise therapy is highly desired. To examine whether the application of group-based motor imagery practice to community-dwelling individuals with chronic hemiparesis improves gait. Sixteen individuals with chronic hemiparesis from two community centers participated in the study, with eight from each center. Four participants in each center received five weeks of the experimental intervention, consisting of group-based motor imagery exercises of gait tasks, followed by five weeks of control treatment of motor imagery exercises for the affected upper extremity. Four other subjects in each center received the same treatments in reverse order. Pre- and post intervention measurements included clinical and biomechanical gait parameters. Comparisons within (pre- vs. post) and between treatments (experimental vs. control) indicated no significant change in any gait variable. Nevertheless, the verbal reports of most participants alluded to satisfaction with the experimental intervention and to an increase in self-confidence. Despite the lack of evidence for the effectiveness of group-based motor imagery practice in improving gait among individuals with chronic hemiparesis, the contrast between the measured outcomes and the positive verbal reports merits further inquiry.

How distributed processing produces false negatives in voxel-based lesion-deficit analyses.

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Gajardo-Vidal, Andrea; Lorca-Puls, Diego L; Crinion, Jennifer T; White, Jitrachote; Seghier, Mohamed L; Leff, Alex P; Hope, Thomas M H; Ludersdorfer, Philipp; Green, David W; Bowman, Howard; Price, Cathy J

2018-07-01

In this study, we hypothesized that if the same deficit can be caused by damage to one or another part of a distributed neural system, then voxel-based analyses might miss critical lesion sites because preservation of each site will not be consistently associated with preserved function. The first part of our investigation used voxel-based multiple regression analyses of data from 359 right-handed stroke survivors to identify brain regions where lesion load is associated with picture naming abilities after factoring out variance related to object recognition, semantics and speech articulation so as to focus on deficits arising at the word retrieval level. A highly significant lesion-deficit relationship was identified in left temporal and frontal/premotor regions. Post-hoc analyses showed that damage to either of these sites caused the deficit of interest in less than half the affected patients (76/162 = 47%). After excluding all patients with damage to one or both of the identified regions, our second analysis revealed a new region, in the anterior part of the left putamen, which had not been previously detected because many patients had the deficit of interest after temporal or frontal damage that preserved the left putamen. The results illustrate how (i) false negative results arise when the same deficit can be caused by different lesion sites; (ii) some of the missed effects can be unveiled by adopting an iterative approach that systematically excludes patients with lesions to the areas identified in previous analyses, (iii) statistically significant voxel-based lesion-deficit mappings can be driven by a subset of patients; (iv) focal lesions to the identified regions are needed to determine whether the deficit of interest is the consequence of focal damage or much more extensive damage that includes the identified region; and, finally, (v) univariate voxel-based lesion-deficit mappings cannot, in isolation, be used to predict outcome in other patients

Monte Carlo study of voxel S factor dependence on tissue density and atomic composition

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Amato, Ernesto, E-mail: eamato@unime.it [University of Messina, Department of Biomedical Sciences and of Morphologic and Functional Imaging, Section of Radiological Sciences, via Consolare Valeria, 1, I-98125 Messina (Italy); Italiano, Antonio [INFN – Istituto Nazionale di Fisica Nucleare, Gruppo Collegato di Messina (Italy); Baldari, Sergio [University of Messina, Department of Biomedical Sciences and of Morphologic and Functional Imaging, Section of Radiological Sciences, via Consolare Valeria, 1, I-98125 Messina (Italy)

2013-11-21

Voxel dosimetry is a common approach to the internal dosimetry of non-uniform activity distributions in nuclear medicine therapies with radiopharmaceuticals and in the estimation of the radiation hazard due to internal contamination of radionuclides. Aim of the present work is to extend our analytical approach for the calculation of voxel S factors to materials different from the soft tissue. We used a Monte Carlo simulation in GEANT4 of a voxelized region of each material in which the source of monoenergetic electrons or photons was uniformly distributed within the central voxel, and the energy deposition was scored over the surrounding 11×11×11 voxels. Voxel S factors were obtained for the following standard ICRP materials: Adipose tissue, Bone cortical, Brain, Lung, Muscle skeletal and Tissue soft with 1 g cm{sup −3} density. Moreover, we considered the standard ICRU materials: Bone compact and Muscle striated. Voxel S factors were represented as a function of the “normalized radius”, defined as the ratio between the source–target voxel distance and the voxel side. We found that voxel S factors and related analytical fit functions are mainly affected by the tissue density, while the material composition gives only a slight contribution to the difference between data series, which is negligible for practical purposes. Our results can help in broadening the dosimetric three-dimensional approach based on voxel S factors to other tissues where diagnostic and therapeutic radionuclides can be taken up and radiation can propagate.

Monte Carlo study of voxel S factor dependence on tissue density and atomic composition

International Nuclear Information System (INIS)

Amato, Ernesto; Italiano, Antonio; Baldari, Sergio

2013-01-01

Voxel dosimetry is a common approach to the internal dosimetry of non-uniform activity distributions in nuclear medicine therapies with radiopharmaceuticals and in the estimation of the radiation hazard due to internal contamination of radionuclides. Aim of the present work is to extend our analytical approach for the calculation of voxel S factors to materials different from the soft tissue. We used a Monte Carlo simulation in GEANT4 of a voxelized region of each material in which the source of monoenergetic electrons or photons was uniformly distributed within the central voxel, and the energy deposition was scored over the surrounding 11×11×11 voxels. Voxel S factors were obtained for the following standard ICRP materials: Adipose tissue, Bone cortical, Brain, Lung, Muscle skeletal and Tissue soft with 1 g cm −3 density. Moreover, we considered the standard ICRU materials: Bone compact and Muscle striated. Voxel S factors were represented as a function of the “normalized radius”, defined as the ratio between the source–target voxel distance and the voxel side. We found that voxel S factors and related analytical fit functions are mainly affected by the tissue density, while the material composition gives only a slight contribution to the difference between data series, which is negligible for practical purposes. Our results can help in broadening the dosimetric three-dimensional approach based on voxel S factors to other tissues where diagnostic and therapeutic radionuclides can be taken up and radiation can propagate

Neurofunctional maps of the 'maternal brain' and the effects of oxytocin: a multimodal voxel-based meta-analysis.

Science.gov (United States)

Rocchetti, Matteo; Radua, Joaquim; Paloyelis, Yannis; Xenaki, Lida-Alkisti; Frascarelli, Marianna; Caverzasi, Edgardo; Politi, Pierluigi; Fusar-Poli, Paolo

2014-10-01

Several studies have tried to understand the possible neurobiological basis of mothering. The putative involvement of oxytocin, in this regard, has been deeply investigated. Performing a voxel-based meta-analysis, we aimed at testing the hypothesis of overlapping brain activation in functional magnetic resonance imaging (fMRI) studies investigating the mother-infant interaction and the oxytocin modulation of emotional stimuli in humans. We performed two systematic literature searches: fMRI studies investigating the neurofunctional correlates of the 'maternal brain' by employing mother-infant paradigms; and fMRI studies employing oxytocin during emotional tasks. A unimodal voxel-based meta-analysis was performed on each database, whereas a multimodal voxel-based meta-analytical tool was adopted to assess the hypothesis that the neurofunctional effects of oxytocin are detected in brain areas implicated in the 'maternal brain.' We found greater activation in the bilateral insula extending to the inferior frontal gyrus, basal ganglia and thalamus during mother-infant interaction and greater left insular activation associated with oxytocin administration versus placebo. Left insula extending to basal ganglia and frontotemporal gyri as well as bilateral thalamus and amygdala showed consistent activation across the two paradigms. Right insula also showed activation across the two paradigms, and dorsomedial frontal cortex activation in mothers but deactivation with oxytocin. Significant activation in areas involved in empathy, emotion regulation, motivation, social cognition and theory of mind emerged from our multimodal meta-analysis, supporting the need for further studies directly investigating the neurobiology of oxytocin in the mother-infant relationship. © 2014 The Authors. Psychiatry and Clinical Neurosciences © 2014 Japanese Society of Psychiatry and Neurology.

Flexible Piezoelectric Sensor-Based Gait Recognition

Directory of Open Access Journals (Sweden)

Youngsu Cha

2018-02-01

Full Text Available Most motion recognition research has required tight-fitting suits for precise sensing. However, tight-suit systems have difficulty adapting to real applications, because people normally wear loose clothes. In this paper, we propose a gait recognition system with flexible piezoelectric sensors in loose clothing. The gait recognition system does not directly sense lower-body angles. It does, however, detect the transition between standing and walking. Specifically, we use the signals from the flexible sensors attached to the knee and hip parts on loose pants. We detect the periodic motion component using the discrete time Fourier series from the signal during walking. We adapt the gait detection method to a real-time patient motion and posture monitoring system. In the monitoring system, the gait recognition operates well. Finally, we test the gait recognition system with 10 subjects, for which the proposed system successfully detects walking with a success rate over 93 %.

Curve aligning approach for gait authentication based on a wearable accelerometer

International Nuclear Information System (INIS)

Sun, Hu; Yuao, Tao

2012-01-01

Gait authentication based on a wearable accelerometer is a novel biometric which can be used for identity identification, medical rehabilitation and early detection of neurological disorders. The method for matching gait patterns tells heavily on authentication performances. In this paper, curve aligning is introduced as a new method for matching gait patterns and it is compared with correlation and dynamic time warping (DTW). A support vector machine (SVM) is proposed to fuse pattern-matching methods in a decision level. Accelerations collected from ankles of 22 walking subjects are processed for authentications in our experiments. The fusion of curve aligning with backward–forward accelerations and DTW with vertical accelerations promotes authentication performances substantially and consistently. This fusion algorithm is tested repeatedly. Its mean and standard deviation of equal error rates are 0.794% and 0.696%, respectively, whereas among all presented non-fusion algorithms, the best one shows an EER of 3.03%. (paper)

Gait disorder rehabilitation using vision and non-vision based sensors: A systematic review

Directory of Open Access Journals (Sweden)

Asraf Ali

2012-08-01

Full Text Available Even though the amount of rehabilitation guidelines has never been greater, uncertainty continues to arise regarding the efficiency and effectiveness of the rehabilitation of gait disorders. This question has been hindered by the lack of information on accurate measurements of gait disorders. Thus, this article reviews the rehabilitation systems for gait disorder using vision and non-vision sensor technologies, as well as the combination of these. All papers published in the English language between 1990 and June, 2012 that had the phrases “gait disorder” “rehabilitation”, “vision sensor”, or “non vision sensor” in the title, abstract, or keywords were identified from the SpringerLink, ELSEVIER, PubMed, and IEEE databases. Some synonyms of these phrases and the logical words “and” “or” and “not” were also used in the article searching procedure. Out of the 91 published articles found, this review identified 84 articles that described the rehabilitation of gait disorders using different types of sensor technologies. This literature set presented strong evidence for the development of rehabilitation systems using a markerless vision-based sensor technology. We therefore believe that the information contained in this review paper will assist the progress of the development of rehabilitation systems for human gait disorders.

IMU-Based Gait Recognition Using Convolutional Neural Networks and Multi-Sensor Fusion

Directory of Open Access Journals (Sweden)

Omid Dehzangi

2017-11-01

Full Text Available The wide spread usage of wearable sensors such as in smart watches has provided continuous access to valuable user generated data such as human motion that could be used to identify an individual based on his/her motion patterns such as, gait. Several methods have been suggested to extract various heuristic and high-level features from gait motion data to identify discriminative gait signatures and distinguish the target individual from others. However, the manual and hand crafted feature extraction is error prone and subjective. Furthermore, the motion data collected from inertial sensors have complex structure and the detachment between manual feature extraction module and the predictive learning models might limit the generalization capabilities. In this paper, we propose a novel approach for human gait identification using time-frequency (TF expansion of human gait cycles in order to capture joint 2 dimensional (2D spectral and temporal patterns of gait cycles. Then, we design a deep convolutional neural network (DCNN learning to extract discriminative features from the 2D expanded gait cycles and jointly optimize the identification model and the spectro-temporal features in a discriminative fashion. We collect raw motion data from five inertial sensors placed at the chest, lower-back, right hand wrist, right knee, and right ankle of each human subject synchronously in order to investigate the impact of sensor location on the gait identification performance. We then present two methods for early (input level and late (decision score level multi-sensor fusion to improve the gait identification generalization performance. We specifically propose the minimum error score fusion (MESF method that discriminatively learns the linear fusion weights of individual DCNN scores at the decision level by minimizing the error rate on the training data in an iterative manner. 10 subjects participated in this study and hence, the problem is a 10-class

A training program to improve gait while dual tasking in patients with Parkinson's disease: a pilot study.

Science.gov (United States)

Yogev-Seligmann, Galit; Giladi, Nir; Brozgol, Marina; Hausdorff, Jeffrey M

2012-01-01

Impairments in the ability to perform another task while walking (ie, dual tasking [DT]) are associated with an increased risk of falling. Here we describe a program we developed specifically to improve DT performance while walking based on motor learning principles and task-specific training. We examined feasibility, potential efficacy, retention, and transfer to the performance of untrained tasks in a pilot study among 7 patients with Parkinson's disease (PD). Seven patients (Hoehn and Yahr stage, 2.1±0.2) were evaluated before, after, and 1 month after 4 weeks of DT training. Gait speed and gait variability were measured during usual walking and during 4 DT conditions. The 4-week program of one-on-one training included walking while performing several distinct cognitive tasks. Gait speed and gait variability during DT significantly improved. Improvements were also seen in the DT conditions that were not specifically trained and were retained 1 month after training. These initial findings support the feasibility of applying a task-specific DT gait training program for patients with PD and suggest that it positively affects DT gait, even in untrained tasks. The present results are also consistent with the possibility that DT gait training enhances divided attention abilities during walking. Copyright © 2012 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Evaluation of absorbed doses in voxel-based and simplified models for small animals

International Nuclear Information System (INIS)

Mohammadi, A.; Kinase, S.; Saito, K.

2008-01-01

Internal dosimetry in non-human biota is desirable from the viewpoint of radiation protection of the environment. The International Commission on Radiological Protection (ICRP) proposed Reference Animals and Plants using simplified models, such as ellipsoids and spheres and calculated absorbed fractions (AFs) for whole bodies. In this study, photon and electron AFs in whole bodies of voxel-based rat and frog models have been calculated and compared with AFs in the reference models. It was found that the voxel-based and the reference frog (or rat) models can be consistent for the whole-body AFs within a discrepancy of 25 %, as the source was uniformly distributed in the whole body. The specific absorbed fractions (SAFs) and S values were also evaluated in whole bodies and all organs of the voxel-based frog and rat models as the source was distributed in the whole body or skeleton. The results demonstrated that the whole-body SAFs reflect SAFs of all individual organs as the source was uniformly distributed per mass within the whole body by about 30 % uncertainties with exceptions for body contour (up to -40 %) for both electrons and photons due to enhanced radiation leakages, and for the skeleton for photons only (up to +185 %) due to differences in the mass attenuation coefficients. For nuclides such as 90 Y and 90 Sr, which were concentrated in the skeleton, there were large differences between S values in the whole body and those in individual organs, however the whole-body S values for the reference models with the whole body as the source were remarkably similar to those for the voxel-based models with the skeleton as the source, within about 4 and 0.3 %, respectively. It can be stated that whole-body SAFs or S values in simplified models without internal organs are not sufficient for accurate internal dosimetry because they do not reflect SAFs or S values of all individual organs as the source was not distributed uniformly in whole body. Thus, voxel-based

Whole-brain voxel-based morphometry of white matter in medial temporal lobe epilepsy

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Yu Aihong [Department of Radiology, Xuanwu Hospital, Capital University of Medical Sciences, Beijing 100053 (China); Li Kuncheng [Department of Radiology, Xuanwu Hospital, Capital University of Medical Sciences, Beijing 100053 (China)], E-mail: Likuncheng@vip.sina.com; Li Lin; Shan Baoci [Institute of High Energy Physics, Chinese Academy of Sciences (China); Wang Yuping; Xue Sufang [Department of Neurology, Xuanwu Hospital, Capital University of Medical Sciences (China)

2008-01-15

Purpose: The purpose of this study was to analyze whole-brain white matter changes in medial temporal lobe epilepsy (MTLE). Materials and methods: We studied 23 patients with MTLE and 13 age- and sex-matched healthy control subjects using voxel-based morphometry (VBM) on T1-weighted 3D datasets. The seizure focus was right sided in 11 patients and left sided in 12. The data were collected on a 1.5 T MR system and analyzed by SPM 99 to generate white matter density maps. Results: Voxel-based morphometry revealed diffusively reduced white matter in MTLE prominently including bilateral frontal lobes, bilateral temporal lobes and corpus callosum. White matter reduction was also found in the bilateral cerebellar hemispheres in the left MTLE group. Conclusion: VBM is a simple and automated approach that is able to identify diffuse whole-brain white matter reduction in MTLE.

Whole-brain voxel-based morphometry of white matter in medial temporal lobe epilepsy

International Nuclear Information System (INIS)

Yu Aihong; Li Kuncheng; Li Lin; Shan Baoci; Wang Yuping; Xue Sufang

2008-01-01

Purpose: The purpose of this study was to analyze whole-brain white matter changes in medial temporal lobe epilepsy (MTLE). Materials and methods: We studied 23 patients with MTLE and 13 age- and sex-matched healthy control subjects using voxel-based morphometry (VBM) on T1-weighted 3D datasets. The seizure focus was right sided in 11 patients and left sided in 12. The data were collected on a 1.5 T MR system and analyzed by SPM 99 to generate white matter density maps. Results: Voxel-based morphometry revealed diffusively reduced white matter in MTLE prominently including bilateral frontal lobes, bilateral temporal lobes and corpus callosum. White matter reduction was also found in the bilateral cerebellar hemispheres in the left MTLE group. Conclusion: VBM is a simple and automated approach that is able to identify diffuse whole-brain white matter reduction in MTLE

A Neural Network-Based Gait Phase Classification Method Using Sensors Equipped on Lower Limb Exoskeleton Robots.

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Jung, Jun-Young; Heo, Wonho; Yang, Hyundae; Park, Hyunsub

2015-10-30

An exact classification of different gait phases is essential to enable the control of exoskeleton robots and detect the intentions of users. We propose a gait phase classification method based on neural networks using sensor signals from lower limb exoskeleton robots. In such robots, foot sensors with force sensing registers are commonly used to classify gait phases. We describe classifiers that use the orientation of each lower limb segment and the angular velocities of the joints to output the current gait phase. Experiments to obtain the input signals and desired outputs for the learning and validation process are conducted, and two neural network methods (a multilayer perceptron and nonlinear autoregressive with external inputs (NARX)) are used to develop an optimal classifier. Offline and online evaluations using four criteria are used to compare the performance of the classifiers. The proposed NARX-based method exhibits sufficiently good performance to replace foot sensors as a means of classifying gait phases.

Ergonomics, anthropometrics, and kinetic evaluation of gait: A case study

OpenAIRE

Lima, Rosa; Fontes, Liliana Magalhães Campos; Arezes, P.; Carvalho, Miguel

2015-01-01

This study aimed to develop appropriate changes in a pair of shoes in order to improve the gait of an individual selected for this case study. This analysis took into account ergonomic aspects, namely those relating to the individual’s anthropometrics. Gait analysis was done with the adapted footwear both before and after intervention.A conventional X-ray was performed, which revealed a 29-mm left lower limb shortening and possible foot adduction. The anthropometric assessment confir...

The Relevance Voxel Machine (RVoxM): A Bayesian Method for Image-Based Prediction

DEFF Research Database (Denmark)

Sabuncu, Mert R.; Van Leemput, Koen

2011-01-01

This paper presents the Relevance VoxelMachine (RVoxM), a Bayesian multivariate pattern analysis (MVPA) algorithm that is specifically designed for making predictions based on image data. In contrast to generic MVPA algorithms that have often been used for this purpose, the method is designed to ...

The effect of uphill and downhill walking on gait parameters: A self-paced treadmill study.

Science.gov (United States)

Kimel-Naor, Shani; Gottlieb, Amihai; Plotnik, Meir

2017-07-26

It has been shown that gait parameters vary systematically with the slope of the surface when walking uphill (UH) or downhill (DH) (Andriacchi et al., 1977; Crowe et al., 1996; Kawamura et al., 1991; Kirtley et al., 1985; McIntosh et al., 2006; Sun et al., 1996). However, gait trials performed on inclined surfaces have been subject to certain technical limitations including using fixed speed treadmills (TMs) or, alternatively, sampling only a few gait cycles on inclined ramps. Further, prior work has not analyzed upper body kinematics. This study aims to investigate effects of slope on gait parameters using a self-paced TM (SPTM) which facilitates more natural walking, including measuring upper body kinematics and gait coordination parameters. Gait of 11 young healthy participants was sampled during walking in steady state speed. Measurements were made at slopes of +10°, 0° and -10°. Force plates and a motion capture system were used to reconstruct twenty spatiotemporal gait parameters. For validation, previously described parameters were compared with the literature, and novel parameters measuring upper body kinematics and bilateral gait coordination were also analyzed. Results showed that most lower and upper body gait parameters were affected by walking slope angle. Specifically, UH walking had a higher impact on gait kinematics than DH walking. However, gait coordination parameters were not affected by walking slope, suggesting that gait asymmetry, left-right coordination and gait variability are robust characteristics of walking. The findings of the study are discussed in reference to a potential combined effect of slope and gait speed. Follow-up studies are needed to explore the relative effects of each of these factors. Copyright © 2017. Published by Elsevier Ltd.

Self-esteem recognition based on gait pattern using Kinect.

Science.gov (United States)

Sun, Bingli; Zhang, Zhan; Liu, Xingyun; Hu, Bin; Zhu, Tingshao

2017-10-01

Self-esteem is an important aspect of individual's mental health. When subjects are not able to complete self-report questionnaire, behavioral assessment will be a good supplement. In this paper, we propose to use gait data collected by Kinect as an indicator to recognize self-esteem. 178 graduate students without disabilities participate in our study. Firstly, all participants complete the 10-item Rosenberg Self-Esteem Scale (RSS) to acquire self-esteem score. After completing the RRS, each participant walks for two minutes naturally on a rectangular red carpet, and the gait data are recorded using Kinect sensor. After data preprocessing, we extract a few behavioral features to train predicting model by machine learning. Based on these features, we build predicting models to recognize self-esteem. For self-esteem prediction, the best correlation coefficient between predicted score and self-report score is 0.45 (pself-esteem with a fairly good criterion validity. The gait predicting model can be taken as a good supplementary method to measure self-esteem. Copyright © 2017 Elsevier B.V. All rights reserved.

A gait stability investigation into FES-assisted paraplegic walking based on the walker tipping index.

Science.gov (United States)

Ming, Dong; Bai, Yanru; Liu, Xiuyun; Qi, Hongzhi; Cheng, Longlong; Wan, Baikun; Hu, Yong; Wong, Yatwa; Luk, Keith D K; Leong, John C Y

2009-12-01

The gait outcome measures used in clinical trials of paraplegic locomotor training determine the effectiveness of improved walking function assisted by the functional electrical stimulation (FES) system. Focused on kinematic, kinetic or physiological changes of paraplegic patients, traditional methods cannot quantify the walking stability or identify the unstable factors of gait in real time. Up until now, the published studies on dynamic gait stability for the effective use of FES have been limited. In this paper, the walker tipping index (WTI) was used to analyze and process gait stability in FES-assisted paraplegic walking. The main instrument was a specialized walker dynamometer system based on a multi-channel strain-gauge bridge network fixed on the frame of the walker. This system collected force information for the handle reaction vector between the patient's upper extremities and the walker during the walking process; the information was then converted into walker tipping index data, which is an evaluation indicator of the patient's walking stability. To demonstrate the potential usefulness of WTI in gait analysis, a preliminary clinical trial was conducted with seven paraplegic patients who were undergoing FES-assisted walking training and seven normal control subjects. The gait stability levels were quantified for these patients under different stimulation patterns and controls under normal walking with knee-immobilization through WTI analysis. The results showed that the walking stability in the FES-assisted paraplegic group was worse than that in the control subject group, with the primary concern being in the anterior-posterior plane. This new technique is practical for distinguishing useful gait information from the viewpoint of stability, and may be further applied in FES-assisted paraplegic walking rehabilitation.

A gait stability investigation into FES-assisted paraplegic walking based on the walker tipping index

Science.gov (United States)

Ming, Dong; Bai, Yanru; Liu, Xiuyun; Qi, Hongzhi; Cheng, Longlong; Wan, Baikun; Hu, Yong; Wong, Yatwa; Luk, Keith D. K.; Leong, John C. Y.

2009-12-01

The gait outcome measures used in clinical trials of paraplegic locomotor training determine the effectiveness of improved walking function assisted by the functional electrical stimulation (FES) system. Focused on kinematic, kinetic or physiological changes of paraplegic patients, traditional methods cannot quantify the walking stability or identify the unstable factors of gait in real time. Up until now, the published studies on dynamic gait stability for the effective use of FES have been limited. In this paper, the walker tipping index (WTI) was used to analyze and process gait stability in FES-assisted paraplegic walking. The main instrument was a specialized walker dynamometer system based on a multi-channel strain-gauge bridge network fixed on the frame of the walker. This system collected force information for the handle reaction vector between the patient's upper extremities and the walker during the walking process; the information was then converted into walker tipping index data, which is an evaluation indicator of the patient's walking stability. To demonstrate the potential usefulness of WTI in gait analysis, a preliminary clinical trial was conducted with seven paraplegic patients who were undergoing FES-assisted walking training and seven normal control subjects. The gait stability levels were quantified for these patients under different stimulation patterns and controls under normal walking with knee-immobilization through WTI analysis. The results showed that the walking stability in the FES-assisted paraplegic group was worse than that in the control subject group, with the primary concern being in the anterior-posterior plane. This new technique is practical for distinguishing useful gait information from the viewpoint of stability, and may be further applied in FES-assisted paraplegic walking rehabilitation.

Voxel-Based Morphometry ALE meta-analysis of Bipolar Disorder

Science.gov (United States)

Magana, Omar; Laird, Robert

2012-03-01

A meta-analysis was performed independently to view the changes in gray matter (GM) on patients with Bipolar disorder (BP). The meta-analysis was conducted on a Talairach Space using GingerALE to determine the voxels and their permutation. In order to achieve the data acquisition, published experiments and similar research studies were uploaded onto the online Voxel-Based Morphometry database (VBM). By doing so, coordinates of activation locations were extracted from Bipolar disorder related journals utilizing Sleuth. Once the coordinates of given experiments were selected and imported to GingerALE, a Gaussian was performed on all foci points to create the concentration points of GM on BP patients. The results included volume reductions and variations of GM between Normal Healthy controls and Patients with Bipolar disorder. A significant amount of GM clusters were obtained in Normal Healthy controls over BP patients on the right precentral gyrus, right anterior cingulate, and the left inferior frontal gyrus. In future research, more published journals could be uploaded onto the database and another VBM meta-analysis could be performed including more activation coordinates or a variation of age groups.

A multicriteria framework with voxel-dependent parameters for radiotherapy treatment plan optimization

International Nuclear Information System (INIS)

Zarepisheh, Masoud; Uribe-Sanchez, Andres F.; Li, Nan; Jia, Xun; Jiang, Steve B.

2014-01-01

Purpose: To establish a new mathematical framework for radiotherapy treatment optimization with voxel-dependent optimization parameters. Methods: In the treatment plan optimization problem for radiotherapy, a clinically acceptable plan is usually generated by an optimization process with weighting factors or reference doses adjusted for a set of the objective functions associated to the organs. Recent discoveries indicate that adjusting parameters associated with each voxel may lead to better plan quality. However, it is still unclear regarding the mathematical reasons behind it. Furthermore, questions about the objective function selection and parameter adjustment to assure Pareto optimality as well as the relationship between the optimal solutions obtained from the organ-based and voxel-based models remain unanswered. To answer these questions, the authors establish in this work a new mathematical framework equipped with two theorems. Results: The new framework clarifies the different consequences of adjusting organ-dependent and voxel-dependent parameters for the treatment plan optimization of radiation therapy, as well as the impact of using different objective functions on plan qualities and Pareto surfaces. The main discoveries are threefold: (1) While in the organ-based model the selection of the objective function has an impact on the quality of the optimized plans, this is no longer an issue for the voxel-based model since the Pareto surface is independent of the objective function selection and the entire Pareto surface could be generated as long as the objective function satisfies certain mathematical conditions; (2) All Pareto solutions generated by the organ-based model with different objective functions are parts of a unique Pareto surface generated by the voxel-based model with any appropriate objective function; (3) A much larger Pareto surface is explored by adjusting voxel-dependent parameters than by adjusting organ-dependent parameters, possibly

Statistical Parametric Mapping to Identify Differences between Consensus-Based Joint Patterns during Gait in Children with Cerebral Palsy.

Science.gov (United States)

Nieuwenhuys, Angela; Papageorgiou, Eirini; Desloovere, Kaat; Molenaers, Guy; De Laet, Tinne

2017-01-01

Experts recently identified 49 joint motion patterns in children with cerebral palsy during a Delphi consensus study. Pattern definitions were therefore the result of subjective expert opinion. The present study aims to provide objective, quantitative data supporting the identification of these consensus-based patterns. To do so, statistical parametric mapping was used to compare the mean kinematic waveforms of 154 trials of typically developing children (n = 56) to the mean kinematic waveforms of 1719 trials of children with cerebral palsy (n = 356), which were classified following the classification rules of the Delphi study. Three hypotheses stated that: (a) joint motion patterns with 'no or minor gait deviations' (n = 11 patterns) do not differ significantly from the gait pattern of typically developing children; (b) all other pathological joint motion patterns (n = 38 patterns) differ from typically developing gait and the locations of difference within the gait cycle, highlighted by statistical parametric mapping, concur with the consensus-based classification rules. (c) all joint motion patterns at the level of each joint (n = 49 patterns) differ from each other during at least one phase of the gait cycle. Results showed that: (a) ten patterns with 'no or minor gait deviations' differed somewhat unexpectedly from typically developing gait, but these differences were generally small (≤3°); (b) all other joint motion patterns (n = 38) differed from typically developing gait and the significant locations within the gait cycle that were indicated by the statistical analyses, coincided well with the classification rules; (c) joint motion patterns at the level of each joint significantly differed from each other, apart from two sagittal plane pelvic patterns. In addition to these results, for several joints, statistical analyses indicated other significant areas during the gait cycle that were not included in the pattern definitions of the consensus study

A voxel-based investigation for MRI-only radiotherapy of the brain using ultra short echo times

Science.gov (United States)

Edmund, Jens M.; Kjer, Hans M.; Van Leemput, Koen; Hansen, Rasmus H.; Andersen, Jon AL; Andreasen, Daniel

2014-12-01

Radiotherapy (RT) based on magnetic resonance imaging (MRI) as the only modality, so-called MRI-only RT, would remove the systematic registration error between MR and computed tomography (CT), and provide co-registered MRI for assessment of treatment response and adaptive RT. Electron densities, however, need to be assigned to the MRI images for dose calculation and patient setup based on digitally reconstructed radiographs (DRRs). Here, we investigate the geometric and dosimetric performance for a number of popular voxel-based methods to generate a so-called pseudo CT (pCT). Five patients receiving cranial irradiation, each containing a co-registered MRI and CT scan, were included. An ultra short echo time MRI sequence for bone visualization was used. Six methods were investigated for three popular types of voxel-based approaches; (1) threshold-based segmentation, (2) Bayesian segmentation and (3) statistical regression. Each approach contained two methods. Approach 1 used bulk density assignment of MRI voxels into air, soft tissue and bone based on logical masks and the transverse relaxation time T2 of the bone. Approach 2 used similar bulk density assignments with Bayesian statistics including or excluding additional spatial information. Approach 3 used a statistical regression correlating MRI voxels with their corresponding CT voxels. A similar photon and proton treatment plan was generated for a target positioned between the nasal cavity and the brainstem for all patients. The CT agreement with the pCT of each method was quantified and compared with the other methods geometrically and dosimetrically using both a number of reported metrics and introducing some novel metrics. The best geometrical agreement with CT was obtained with the statistical regression methods which performed significantly better than the threshold and Bayesian segmentation methods (excluding spatial information). All methods agreed significantly better with CT than a reference water MRI

Altered Brain Network in Amyotrophic Lateral Sclerosis: A Resting Graph Theory-Based Network Study at Voxel-Wise Level.

Science.gov (United States)

Zhou, Chaoyang; Hu, Xiaofei; Hu, Jun; Liang, Minglong; Yin, Xuntao; Chen, Lin; Zhang, Jiuquan; Wang, Jian

2016-01-01

Amyotrophic lateral sclerosis (ALS) is a rare degenerative disorder characterized by loss of upper and lower motor neurons. Neuroimaging has provided noticeable evidence that ALS is a complex disease, and shown that anatomical and functional lesions extend beyond precentral cortices and corticospinal tracts, to include the corpus callosum; frontal, sensory, and premotor cortices; thalamus; and midbrain. The aim of this study is to investigate graph theory-based functional network abnormalities at voxel-wise level in ALS patients on a whole brain scale. Forty-three ALS patients and 44 age- and sex-matched healthy volunteers were enrolled. The voxel-wise network degree centrality (DC), a commonly employed graph-based measure of network organization, was used to characterize the alteration of whole brain functional network. Compared with the controls, the ALS patients showed significant increase of DC in the left cerebellum posterior lobes, bilateral cerebellum crus, bilateral occipital poles, right orbital frontal lobe, and bilateral prefrontal lobes; significant decrease of DC in the bilateral primary motor cortex, bilateral sensory motor region, right prefrontal lobe, left bilateral precuneus, bilateral lateral temporal lobes, left cingulate cortex, and bilateral visual processing cortex. The DC's z-scores of right inferior occipital gyrus were significant negative correlated with the ALSFRS-r scores. Our findings confirm that the regions with abnormal network DC in ALS patients were located in multiple brain regions including primary motor, somatosensory and extra-motor areas, supporting the concept that ALS is a multisystem disorder. Specifically, our study found that DC in the visual areas was altered and ALS patients with higher DC in right inferior occipital gyrus have more severity of disease. The result demonstrated that the altered DC value in this region can probably be used to assess severity of ALS.

Altered brain network in Amyotrophic Lateral Sclerosis: a resting graph theory-based network study at voxel-wise level

Directory of Open Access Journals (Sweden)

Chaoyang eZhou

2016-05-01

Full Text Available Amyotrophic lateral sclerosis (ALS is a rare degenerative disorder characterized by loss of upper and lower motor neurons. Neuroimaging has provided noticeable evidence that ALS is a complex disease, and shown that anatomical and functional lesions extend beyond precentral cortices and corticospinal tracts, to include the corpus callosum; frontal, sensory, and premotor cortices; thalamus; and midbrain. The aim of this study is to investigate graph theory-based functional network abnormalities at voxel-wise level in ALS patients on a whole brain scale. Forty-three ALS patients and 44 age- and sex- matched healthy volunteers were enrolled. The voxel-wise network degree centrality (DC, a commonly employed graph-based measure of network organization, was used to characterize the alteration of whole brain functional network. Compared with the controls, the ALS patients showed significant increase of DC in the left cerebellum posterior lobes, bilateral cerebellum crus, bilateral occipital poles, right orbital frontal lobe and bilateral prefrontal lobes; significant decrease of DC in the bilateral primary motor cortex, bilateral sensory motor region, right prefrontal lobe, left bilateral precuneus, bilateral lateral temporal lobes, left cingulate cortex, and bilateral visual processing cortex. The DC’s z-scores of right inferior occipital gyrus were significant negative correlated with the ALSFRS-r scores. Our findings confirm that the regions with abnormal network DC in ALS patients were located in multiple brain regions including primary motor, somatosensory and extra-motor areas, supporting the concept that ALS is a multisystem disorder. Specifically, our study found that DC in the visual areas was altered and ALS patients with higher DC in right inferior occipital gyrus have more severity of disease. The result demonstrated that the altered DC value in this region can probably be used to assess severity of ALS.

A systematic review of gait analysis methods based on inertial sensors and adaptive algorithms.

Science.gov (United States)

Caldas, Rafael; Mundt, Marion; Potthast, Wolfgang; Buarque de Lima Neto, Fernando; Markert, Bernd

2017-09-01

The conventional methods to assess human gait are either expensive or complex to be applied regularly in clinical practice. To reduce the cost and simplify the evaluation, inertial sensors and adaptive algorithms have been utilized, respectively. This paper aims to summarize studies that applied adaptive also called artificial intelligence (AI) algorithms to gait analysis based on inertial sensor data, verifying if they can support the clinical evaluation. Articles were identified through searches of the main databases, which were encompassed from 1968 to October 2016. We have identified 22 studies that met the inclusion criteria. The included papers were analyzed due to their data acquisition and processing methods with specific questionnaires. Concerning the data acquisition, the mean score is 6.1±1.62, what implies that 13 of 22 papers failed to report relevant outcomes. The quality assessment of AI algorithms presents an above-average rating (8.2±1.84). Therefore, AI algorithms seem to be able to support gait analysis based on inertial sensor data. Further research, however, is necessary to enhance and standardize the application in patients, since most of the studies used distinct methods to evaluate healthy subjects. Copyright © 2017 Elsevier B.V. All rights reserved.

Treatment plan modification using voxel-based weighting factors/dose prescription

International Nuclear Information System (INIS)

Wu Chuan; Olivera, Gustavo H; Jeraj, Robert; Keller, Harry; Mackie, Thomas R

2003-01-01

Under various clinical situations, it is desirable to modify the original treatment plan to better suit the clinical goals. In this work, a method to help physicians modify treatment plans based on their clinical preferences is proposed. The method uses a weighted quadratic dose objective function. The commonly used organ-/ROI-based weighting factors are expanded to a set of voxel-based weighting factors in order to obtain greater flexibility in treatment plan modification. Two different but equivalent modification schemes based on Rustem's quadratic programming algorithms -modification of a weighting matrix and modification of prescribed doses - are presented. Case studies demonstrated the effectiveness of the two methods with regard to their capability to fine-tune treatment plans

Inertial Sensor-Based Robust Gait Analysis in Non-Hospital Settings for Neurological Disorders

Directory of Open Access Journals (Sweden)

Can Tunca

2017-04-01

Full Text Available The gold standards for gait analysis are instrumented walkways and marker-based motion capture systems, which require costly infrastructure and are only available in hospitals and specialized gait clinics. Even though the completeness and the accuracy of these systems are unquestionable, a mobile and pervasive gait analysis alternative suitable for non-hospital settings is a clinical necessity. Using inertial sensors for gait analysis has been well explored in the literature with promising results. However, the majority of the existing work does not consider realistic conditions where data collection and sensor placement imperfections are imminent. Moreover, some of the underlying assumptions of the existing work are not compatible with pathological gait, decreasing the accuracy. To overcome these challenges, we propose a foot-mounted inertial sensor-based gait analysis system that extends the well-established zero-velocity update and Kalman filtering methodology. Our system copes with various cases of data collection difficulties and relaxes some of the assumptions invalid for pathological gait (e.g., the assumption of observing a heel strike during a gait cycle. The system is able to extract a rich set of standard gait metrics, including stride length, cadence, cycle time, stance time, swing time, stance ratio, speed, maximum/minimum clearance and turning rate. We validated the spatio-temporal accuracy of the proposed system by comparing the stride length and swing time output with an IR depth-camera-based reference system on a dataset comprised of 22 subjects. Furthermore, to highlight the clinical applicability of the system, we present a clinical discussion of the extracted metrics on a disjoint dataset of 17 subjects with various neurological conditions.

Preparing a voxel-simulator of Alderson Rando physical phantom

International Nuclear Information System (INIS)

Boia, Leonardo S.; Martins, Maximiano C.; Silva, Ademir X.; Salmon Junior, Helio A.; Soares, Alessandro F.N.S.

2011-01-01

There are, nowadays, sorts of anthropomorphycal phantoms which are used for simulation of radiation transport by the matter and also the deposition of energy in such radiation in human tissues and organs, because an in-vitro dosimetry becomes very either complicated or even impossible in some cases. In the present work we prepared a computational phantom in voxels based on computational tomography of Rando-Alderson. This phantom is one of the most known human body simulators on the scope of ionizing radiation dosimetry, and it is used for radioprotection issues and dosimetry from radiotherapy and brachytherapy treatments as well. The preparation of a voxel simulator starts with the image acquisition by a tomograph found at COI/RJ (Clinicas Oncologicas Integradas). The images were generated with 1mm cuts and collected for analysis. After that step the images were processed in SAPDI (Sistema Automatizado de Processamento Digital de Imagem) in order to amplify the images regions intending to facilitate the task in their segmentation. SAPDI is based on parameters described by Hounsfield scale. After that, it has begun discretization of elements in IDs voxels using Scan2MCNP software - which converts images to a sequential text file containing the voxels' IDs ready to be introduced into MCNPX input; however, this set can be turned to a voxel's IDs matrix and used in other Monte Carlo codes, such as Geant4, PENELOPE and EGSnrc. Finished this step, the simulator is able to simulate with accurate geometry the physical phantom. It's possible to study a large number of cases by computational techniques of geometry's insertions of tumors and TLDs, which makes this simulator a research material useful for a lot of subjects. (author)

Preparing a voxel-simulator of Alderson Rando physical phantom

Energy Technology Data Exchange (ETDEWEB)

Boia, Leonardo S.; Martins, Maximiano C.; Silva, Ademir X., E-mail: lboia@con.ufrj.br, E-mail: ademir@con.ufrj.br [Programa de Engenharia Nuclear (PEN/COPPE/UFRJ). Universidade Federal do Rio de Janeiro, RJ (Brazil); Salmon Junior, Helio A., E-mail: heliosalmon@coinet.com.br [COI - Clinicas Oncologicas Integradas, MD.X Barra Medical Center, Rio de Janeiro, RJ (Brazil); Soares, Alessandro F.N.S., E-mail: afacure@cnen.gov.br [Comissao Nacional de Engenharia Nuclear (CNEN), Rio de Janeiro, RJ (Brazil)

2011-07-01

There are, nowadays, sorts of anthropomorphycal phantoms which are used for simulation of radiation transport by the matter and also the deposition of energy in such radiation in human tissues and organs, because an in-vitro dosimetry becomes very either complicated or even impossible in some cases. In the present work we prepared a computational phantom in voxels based on computational tomography of Rando-Alderson. This phantom is one of the most known human body simulators on the scope of ionizing radiation dosimetry, and it is used for radioprotection issues and dosimetry from radiotherapy and brachytherapy treatments as well. The preparation of a voxel simulator starts with the image acquisition by a tomograph found at COI/RJ (Clinicas Oncologicas Integradas). The images were generated with 1mm cuts and collected for analysis. After that step the images were processed in SAPDI (Sistema Automatizado de Processamento Digital de Imagem) in order to amplify the images regions intending to facilitate the task in their segmentation. SAPDI is based on parameters described by Hounsfield scale. After that, it has begun discretization of elements in IDs voxels using Scan2MCNP software - which converts images to a sequential text file containing the voxels' IDs ready to be introduced into MCNPX input; however, this set can be turned to a voxel's IDs matrix and used in other Monte Carlo codes, such as Geant4, PENELOPE and EGSnrc. Finished this step, the simulator is able to simulate with accurate geometry the physical phantom. It's possible to study a large number of cases by computational techniques of geometry's insertions of tumors and TLDs, which makes this simulator a research material useful for a lot of subjects. (author)

Creation of voxel-based models for paediatric dosimetry from automatic segmentation methods

International Nuclear Information System (INIS)

Acosta, O.; Li, R.; Ourselin, S.; Caon, M.

2006-01-01

Full text: The first computational models representing human anatomy were mathematical phantoms, but still far from accurate representations of human body. These models have been used with radiation transport codes (Monte Carlo) to estimate organ doses from radiological procedures. Although new medical imaging techniques have recently allowed the construction of voxel-based models based on the real anatomy, few children models from individual CT or MRI data have been reported [1,3]. For pediatric dosimetry purposes, a large range of voxel models by ages is required since scaling the anatomy from existing models is not sufficiently accurate. The small number of models available arises from the small number of CT or MRI data sets of children available and the long amount of time required to segment the data sets. The existing models have been constructed by manual segmentation slice by slice and using simple thresholding techniques. In medical image segmentation, considerable difficulties appear when applying classical techniques like thresholding or simple edge detection. Until now, any evidence of more accurate or near-automatic methods used in construction of child voxel models exists. We aim to construct a range of pediatric voxel models, integrating automatic or semi-automatic 3D segmentation techniques. In this paper we present the first stage of this work using pediatric CT data.

A mechanical energy analysis of gait initiation

Science.gov (United States)

Miller, C. A.; Verstraete, M. C.

1999-01-01

The analysis of gait initiation (the transient state between standing and walking) is an important diagnostic tool to study pathologic gait and to evaluate prosthetic devices. While past studies have quantified mechanical energy of the body during steady-state gait, to date no one has computed the mechanical energy of the body during gait initiation. In this study, gait initiation in seven normal male subjects was studied using a mechanical energy analysis to compute total body energy. The data showed three separate states: quiet standing, gait initiation, and steady-state gait. During gait initiation, the trends in the energy data for the individual segments were similar to those seen during steady-state gait (and in Winter DA, Quanbury AO, Reimer GD. Analysis of instantaneous energy of normal gait. J Biochem 1976;9:253-257), but diminished in amplitude. However, these amplitudes increased to those seen in steady-state during the gait initiation event (GIE), with the greatest increase occurring in the second step due to the push-off of the foundation leg. The baseline level of mechanical energy was due to the potential energy of the individual segments, while the cyclic nature of the data was indicative of the kinetic energy of the particular leg in swing phase during that step. The data presented showed differences in energy trends during gait initiation from those of steady state, thereby demonstrating the importance of this event in the study of locomotion.

Development and tests of a mouse voxel model dor MCNPX based on Digimouse images

Energy Technology Data Exchange (ETDEWEB)

Melo M, B.; Ferreira F, C. [Centro de Desenvolvimento da Tecnologia Nuclear / CNEN, Pte. Antonio Carlos No. 6627, Belo Horizonte 31270-901, Minas Gerais (Brazil); Garcia de A, I.; Machado T, B.; Passos Ribeiro de C, T., E-mail: bmm@cdtn.br [Universidade Federal de Minas Gerais, Departamento de Engenharia Nuclear, Pte. Antonio Carlos 6627, Belo Horizonte 31270-901, Minas Gerais (Brazil)

2015-10-15

Mice have been widely used in experimental protocols involving ionizing radiation. Biological effects (Be) induced by radiation can compromise studies results. Good estimates of mouse whole body and organs absorbed dose could provide valuable information to researchers. The aim of this study was to create and test a new voxel phantom for mice dosimetry from -Digimouse- project images. Micro CT images from Digimouse project were used in this work. Corel PHOTOPAINT software was utilized in segmentation process. The three-dimensional (3-D) model assembly and its voxel size manipulation were performed by Image J. SISCODES was used to adapt the model to run in MCNPX Monte Carlo code. The resulting model was called DM{sub B}RA. The volume and mass of segmented organs were compared with data available in literature. For the preliminary tests the heart was considered the source organ. Photons of diverse energies were simulated and Saf values obtained through F6:p and + F6 MCNPX tallies. The results were compared with reference data. 3-D picturing of absorbed doses patterns and relative errors distribution were generated by a C++ -in house- made program and visualized through Amide software. The organ masses of DM{sub B}RA correlated well with two models that were based on same set of images. However some organs, like eyes and adrenals, skeleton and brain showed large discrepancies. Segmentation of an identical image set by different persons and/or methods can result significant organ masses variations. We believe that the main causes of these differences were: i) operator dependent subjectivity in the definition of organ limits during the segmentation processes; and i i) distinct voxel dimensions between evaluated models. Lack of reference data for mice models construction and dosimetry was detected. Comparison with other models originated from different mice strains also demonstrated that the anatomical and size variability can be significant. Use of + F6 tally for mouse

Development and tests of a mouse voxel model dor MCNPX based on Digimouse images

International Nuclear Information System (INIS)

Melo M, B.; Ferreira F, C.; Garcia de A, I.; Machado T, B.; Passos Ribeiro de C, T.

2015-10-01

Mice have been widely used in experimental protocols involving ionizing radiation. Biological effects (Be) induced by radiation can compromise studies results. Good estimates of mouse whole body and organs absorbed dose could provide valuable information to researchers. The aim of this study was to create and test a new voxel phantom for mice dosimetry from -Digimouse- project images. Micro CT images from Digimouse project were used in this work. Corel PHOTOPAINT software was utilized in segmentation process. The three-dimensional (3-D) model assembly and its voxel size manipulation were performed by Image J. SISCODES was used to adapt the model to run in MCNPX Monte Carlo code. The resulting model was called DM B RA. The volume and mass of segmented organs were compared with data available in literature. For the preliminary tests the heart was considered the source organ. Photons of diverse energies were simulated and Saf values obtained through F6:p and + F6 MCNPX tallies. The results were compared with reference data. 3-D picturing of absorbed doses patterns and relative errors distribution were generated by a C++ -in house- made program and visualized through Amide software. The organ masses of DM B RA correlated well with two models that were based on same set of images. However some organs, like eyes and adrenals, skeleton and brain showed large discrepancies. Segmentation of an identical image set by different persons and/or methods can result significant organ masses variations. We believe that the main causes of these differences were: i) operator dependent subjectivity in the definition of organ limits during the segmentation processes; and i i) distinct voxel dimensions between evaluated models. Lack of reference data for mice models construction and dosimetry was detected. Comparison with other models originated from different mice strains also demonstrated that the anatomical and size variability can be significant. Use of + F6 tally for mouse phantoms

Gender may have an influence on the relationship between Functional Movement Screen scores and gait parameters in elite junior athletes - A pilot study.

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Magyari, N; Szakács, V; Bartha, C; Szilágyi, B; Galamb, K; Magyar, M O; Hortobágyi, T; Kiss, R M; Tihanyi, J; Négyesi, J

2017-09-01

Aims The aim of this study was to examine the effects of gender on the relationship between Functional Movement Screen (FMS) and treadmill-based gait parameters. Methods Twenty elite junior athletes (10 women and 10 men) performed the FMS tests and gait analysis at a fixed speed. Between-gender differences were calculated for the relationship between FMS test scores and gait parameters, such as foot rotation, step length, and length of gait line. Results Gender did not affect the relationship between FMS and treadmill-based gait parameters. The nature of correlations between FMS test scores and gait parameters was different in women and men. Furthermore, different FMS test scores predicted different gait parameters in female and male athletes. FMS asymmetry and movement asymmetries measured by treadmill-based gait parameters did not correlate in either gender. Conclusion There were no interactions between FMS, gait parameters, and gender; however, correlation analyses support the idea that strength and conditioning coaches need to pay attention not only to how to score but also how to correctly use FMS.

Positive outcomes following gait therapy intervention for hip osteoarthritis: A longitudinal study.

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Solomonow-Avnon, Deborah; Herman, Amir; Levin, Daniel; Rozen, Nimrod; Peled, Eli; Wolf, Alon

2017-10-01

Footwear-generated biomechanical manipulation of lower-limb joints was shown to beneficially impact gait and quality of life in knee osteoarthritis patients, but has not been tested in hip osteoarthritis patients. We examined a customized gait treatment program using a biomechanical device shown in previous investigations to be capable of manipulating hip biomechanics via foot center of pressure (COP) modulation. The objective of this study was to assess the treatment program for hip osteoarthritis patients, enrolled in a 1-year prospective investigation, by means of objective gait and spatiotemporal parameters, and subjective quality of life measures. Gait analysis and completion of questionnaires were performed at the start of the treatment (baseline), and after 3, 6, and 12 months. Outcome parameters were evaluated over time using linear mixed effects models, and association between improvement in quality of life measures and change in objective outcomes was tested using mixed effect linear regression models. Quality of life measures improved compared to baseline, accompanied by increased gait speed and cadence. Sagittal-plane hip joint kinetics, kinematics, and spatiotemporal parameters changed throughout the study compared to baseline, in a manner suggesting improvement of gait. The most substantial improvement occurred within 3 months after treatment initiation, after which improvement approximately plateaued, but was sustained at 12 months. Speed and cadence, as well as several sagittal-plane gait parameters, were significant predictors of improvement in quality of life. Evidence suggests that a biomechanical gait therapy program improves subjective and objective outcomes measures and is a valid treatment option for hip osteoarthritis. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:2222-2232, 2017. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

Combining Gait Speed and Recall Memory to Predict Survival in Late Life: Population-Based Study.

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Marengoni, Alessandra; Bandinelli, Stefania; Maietti, Elisa; Guralnik, Jack; Zuliani, Giovanni; Ferrucci, Luigi; Volpato, Stefano

2017-03-01

To evaluate the relationship between gait speed, recall memory, and mortality. A cohort study (last follow-up December 2009). Tuscany, Italy. Individual data from 1,014 community-dwelling older adults aged 60 years or older with baseline gait speed and recall memory measurements and follow-up for a median time of 9.10 (IQR 7.1;9.3) years. Participants were a mean (SD) age of 73.9 (7.3) years, and 55.8% women. Participants walking faster than 0.8 m/s were defined as fast walkers; good recall memory was defined as a score of 2 or 3 in the 3-word delayed recall section of the Mini-Mental State Examination. All-cause mortality. There were 302 deaths and the overall 100 person-year death rate was 3.77 (95% CI: 3.37-4.22). Both low gait speed and poor recall memory were associated with mortality when analysed separately (HR = 2.47; 95% CI: 1.87-3.27 and HR = 1.47; 95% CI: 1.16-1.87, respectively). When we grouped participants according to both recall and gait speed, death rates (100 person-years) progressively increased from those with both good gait speed and memory (2.0; 95% CI: 1.6-2.5), to those with fast walk but poor memory (3.4; 95% CI: 2.8-4.2), to those with slow walk and good memory (8.8; 95% CI: 6.4-12.1), to those with both slow walk and poor memory (13.0; 95% CI: 10.6-16.1). In multivariate analysis, poor memory significantly increases mortality risk among persons with fast gait speed (HR = 1.40; 95% CI: 1.04-1.89). In older persons, gait speed and recall memory are independent predictors of expected survival. Information on memory function might better stratify mortality risk among persons with fast gait speed. © 2016, Copyright the Authors Journal compilation © 2016, The American Geriatrics Society.

Repeated intravenous administration of gadobutrol does not lead to increased signal intensity on unenhanced T1-weighted images - a voxel-based whole brain analysis

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Langner, Soenke; Kromrey, Marie-Luise [University Medicine Greifswald, Institute of Diagnostic Radiology and Neuroradiology, Greifswald (Germany); Kuehn, Jens-Peter [University Medicine Greifswald, Institute of Diagnostic Radiology and Neuroradiology, Greifswald (Germany); University Hospital, Carl Gustav Carus University Dresden, Institute for Radiology, Dresden (Germany); Grothe, Matthias [University Medicine Greifswald, Department of Neurology, Greifswald (Germany); Domin, Martin [University Medicine Greifswald, Functional Imaging Unit, Institute of Diagnostic Radiology and Neuroradiology, Greifswald (Germany)

2017-09-15

To identify a possible association between repeated intravenous administration of gadobutrol and increased signal intensity in the grey and white matter using voxel-based whole-brain analysis. In this retrospective single-centre study, 217 patients with a clinically isolated syndrome underwent baseline brain magnetic resonance imaging and at least one annual follow-up examination with intravenous administration of 0.1 mmol/kg body weight of gadobutrol. Using the ''Diffeomorphic Anatomical Registration using Exponentiated Lie algebra'' (DARTEL) normalisation process, tissue templates for grey matter (GM), white matter (WM), and cerebrospinal fluid (CSF) were calculated, as were GM-CSF and WM-CSF ratios. Voxel-based whole-brain analysis was used to calculate the signal intensity for each voxel in each data set. Paired t-test was applied to test differences to baseline MRI for significance. Voxel-based whole-brain analysis demonstrated no significant changes in signal intensity of grey and white matter after up to five gadobutrol administrations. There was no significant change in GM-CSF and grey WM-CSF ratios. Voxel-based whole-brain analysis did not demonstrate increased signal intensity of GM and WM on unenhanced T1-weighted images after repeated gadobutrol administration. The molecular structure of gadolinium-based contrast agent preparations may be an essential factor causing SI increase on unenhanced T1-weighted images. (orig.)

Advanced Prosthetic Gait Training Tool

Science.gov (United States)

2015-12-01

modules to train individuals to distinguish gait deviations (trunk motion and lower-limb motion). Each of these modules help trainers improve their...AWARD NUMBER: W81XWH-10-1-0870 TITLE: Advanced Prosthetic Gait Training Tool PRINCIPAL INVESTIGATOR: Dr. Karim Abdel-Malek CONTRACTING...study is to produce a computer-based Advanced Prosthetic Gait Training Tool to aid in the training of clinicians at military treatment facilities

Personality traits related to juvenile myoclonic epilepsy: MRI reveals prefrontal abnormalities through a voxel-based morphometry study.

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de Araújo Filho, Gerardo Maria; Jackowski, Andrea Parolin; Lin, Katia; Guaranha, Mirian S B; Guilhoto, Laura M F F; da Silva, Henrique Hattori; Caboclo, Luís Otávio Sales Ferreira; Júnior, Henrique Carrete; Bressan, Rodrigo Affonseca; Yacubian, Elza Márcia T

2009-06-01

Studies involving juvenile myoclonic epilepsy (JME) patients have demonstrated an elevated prevalence of cluster B personality disorders (PD) characterized as emotional instability, immaturity, unsteadiness, lack of discipline, and rapid mood changes. We aimed to verify a possible correlation between structural brain abnormalities in magnetic resonance image (MRI) and the PD in JME using voxel-based morphometry (VBM). Sixteen JME patients with cluster B PD, 38 JME patients without psychiatric disorders, and 30 healthy controls were submitted to a psychiatric evaluation through SCID I and II and to a MRI scan. Significant reduction in thalami and increase in mesiofrontal and frontobasal regions' volumes were observed mainly in JME patients with PD. Structural alterations of the orbitofrontal cortex (OFC), involved in regulation of mood reactivity, impulsivity, and social behavior, were also observed. This study supports the hypothesis of frontobasal involvement in the pathophysiology of cluster B PD related to JME.

Physiotherapy, based on the Bobath concept, may influence the gait pattern in persons with limb-girdle muscle dystrophy: a multiple case series study.

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Oygard, Kjellaug; Haestad, Helge; Jørgensen, Lone

2011-03-01

 There are few studies on possible effects of physiotherapy for adults with muscular dystrophy. The aim of this study was to examine if treatment based on the Bobath concept may influence specific gait parameters in some of these patients.   A single-subject experimental design with A-B-A-A phases was used, and four patients, three with limb-girdle muscular dystrophy (LGMD) and one with fascioscapulohumeral muscular dystrophy (FSHD), were included. The patients had 1 hour of individually tailored physiotherapy at each working day for a period of 3 weeks. Step length, step width and gait velocity were measured during the A-B-A-A phases by use of an electronic walkway. Walking distance and endurance were measured by use of the '6 minute walk test'.  . The three LGMD patients, who initially walked with a wide base of support, had a narrower, velocity-adjusted step width after treatment, accompanied with the same or even longer step length. These changes lasted throughout follow-up. Moreover, two of the patients were able to walk a longer distance within 6 minutes after the treatment period. The fourth patient (with FSHD) had a normal step width at baseline, which did not change during the study.   The results indicate that physiotherapy treatment based on the Bobath concept may influence the gait pattern in patients with LGMD. However, in order to evaluate the effectiveness of physiotherapy to patients with muscular dystrophies, we call for larger studies and controlled trials. Copyright © 2010 John Wiley & Sons, Ltd.

Global and regional brain volumes normalization in weight-recovered adolescents with anorexia nervosa: preliminary findings of a longitudinal voxel-based morphometry study

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Bomba M

2015-03-01

Full Text Available Monica Bomba,1,* Anna Riva,1,* Sabrina Morzenti,2 Marco Grimaldi,3 Francesca Neri,1 Renata Nacinovich1 1Child and Adolescent Mental Health Department, San Gerardo Hospital, University of Milano-Bicocca, Monza, Italy; 2Medical Physics Department, San Gerardo Hospital, Monza, Italy; 3Department of Radiology, Humanitas Research Hospital, Milan, Italy *These authors contributed equally to this work Abstract: The recent literature on anorexia nervosa (AN suggests that functional and structural abnormalities of cortico-limbic areas might play a role in the evolution of the disease. We explored global and regional brain volumes in a cross-sectional and follow-up study on adolescents affected by AN. Eleven adolescents with AN underwent a voxel-based morphometry study at time of diagnosis and immediately after weight recovery. Data were compared to volumes carried out in eight healthy, age and sex matched controls. Subjects with AN showed increased cerebrospinal fluid volumes and decreased white and gray matter volumes, when compared to controls. Moreover, significant regional gray matter decrease in insular cortex and cerebellum was found at time of diagnosis. No regional white matter decrease was found between samples and controls. Correlations between psychological evaluation and insular volumes were explored. After weight recovery gray matter volumes normalized while reduced global white matter volumes persisted. Keywords: anorexia nervosa, adolescent, gray matter, insula, voxel-based morphometry study

A non-voxel-based broad-beam (NVBB) framework for IMRT treatment planning.

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Lu, Weiguo

2010-12-07

We present a novel framework that enables very large scale intensity-modulated radiation therapy (IMRT) planning in limited computation resources with improvements in cost, plan quality and planning throughput. Current IMRT optimization uses a voxel-based beamlet superposition (VBS) framework that requires pre-calculation and storage of a large amount of beamlet data, resulting in large temporal and spatial complexity. We developed a non-voxel-based broad-beam (NVBB) framework for IMRT capable of direct treatment parameter optimization (DTPO). In this framework, both objective function and derivative are evaluated based on the continuous viewpoint, abandoning 'voxel' and 'beamlet' representations. Thus pre-calculation and storage of beamlets are no longer needed. The NVBB framework has linear complexities (O(N(3))) in both space and time. The low memory, full computation and data parallelization nature of the framework render its efficient implementation on the graphic processing unit (GPU). We implemented the NVBB framework and incorporated it with the TomoTherapy treatment planning system (TPS). The new TPS runs on a single workstation with one GPU card (NVBB-GPU). Extensive verification/validation tests were performed in house and via third parties. Benchmarks on dose accuracy, plan quality and throughput were compared with the commercial TomoTherapy TPS that is based on the VBS framework and uses a computer cluster with 14 nodes (VBS-cluster). For all tests, the dose accuracy of these two TPSs is comparable (within 1%). Plan qualities were comparable with no clinically significant difference for most cases except that superior target uniformity was seen in the NVBB-GPU for some cases. However, the planning time using the NVBB-GPU was reduced many folds over the VBS-cluster. In conclusion, we developed a novel NVBB framework for IMRT optimization. The continuous viewpoint and DTPO nature of the algorithm eliminate the need for beamlets and lead to better plan

A non-voxel-based broad-beam (NVBB) framework for IMRT treatment planning

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Lu Weiguo, E-mail: wlu@tomotherapy.co [TomoTherapy Inc., 1240 Deming Way, Madison, WI 53717 (United States)

2010-12-07

We present a novel framework that enables very large scale intensity-modulated radiation therapy (IMRT) planning in limited computation resources with improvements in cost, plan quality and planning throughput. Current IMRT optimization uses a voxel-based beamlet superposition (VBS) framework that requires pre-calculation and storage of a large amount of beamlet data, resulting in large temporal and spatial complexity. We developed a non-voxel-based broad-beam (NVBB) framework for IMRT capable of direct treatment parameter optimization (DTPO). In this framework, both objective function and derivative are evaluated based on the continuous viewpoint, abandoning 'voxel' and 'beamlet' representations. Thus pre-calculation and storage of beamlets are no longer needed. The NVBB framework has linear complexities (O(N{sup 3})) in both space and time. The low memory, full computation and data parallelization nature of the framework render its efficient implementation on the graphic processing unit (GPU). We implemented the NVBB framework and incorporated it with the TomoTherapy treatment planning system (TPS). The new TPS runs on a single workstation with one GPU card (NVBB-GPU). Extensive verification/validation tests were performed in house and via third parties. Benchmarks on dose accuracy, plan quality and throughput were compared with the commercial TomoTherapy TPS that is based on the VBS framework and uses a computer cluster with 14 nodes (VBS-cluster). For all tests, the dose accuracy of these two TPSs is comparable (within 1%). Plan qualities were comparable with no clinically significant difference for most cases except that superior target uniformity was seen in the NVBB-GPU for some cases. However, the planning time using the NVBB-GPU was reduced many folds over the VBS-cluster. In conclusion, we developed a novel NVBB framework for IMRT optimization. The continuous viewpoint and DTPO nature of the algorithm eliminate the need for beamlets

Grey matter, an endophenotype for schizophrenia? A voxel-based morphometry study in siblings of patients with schizophrenia.

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van der Velde, Jorien; Gromann, Paula M; Swart, Marte; de Haan, Lieuwe; Wiersma, Durk; Bruggeman, Richard; Krabbendam, Lydia; Aleman, André

2015-05-01

Grey matter, both volume and concentration, has been proposed as an endophenotype for schizophrenia given a number of reports of grey matter abnormalities in relatives of patients with schizophrenia. However, previous studies on grey matter abnormalities in relatives have produced inconsistent results. The aim of the present study was to examine grey matter differences between controls and siblings of patients with schizophrenia and to examine whether the age, genetic loading or subclinical psychotic symptoms of selected individuals could explain the previously reported inconsistencies. We compared the grey matter volume and grey matter concentration of healthy siblings of patients with schizophrenia and healthy controls matched for age, sex and education using voxel-based morphometry (VBM). Furthermore, we selected subsamples based on age (grey matter volume or concentration. Furthermore, specifically selecting participants based on age, genetic loading or subclinical psychotic symptoms did not alter these findings. The main limitation was that subdividing the sample resulted in smaller samples for the subanalyses. Furthermore, we used MRI data from 2 different scanner sites. These results indicate that grey matter measured through VBM might not be a suitable endophenotype for schizophrenia.

Loss aversion is associated with bilateral insula volume. A voxel based morphometry study.

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Markett, S; Heeren, G; Montag, C; Weber, B; Reuter, M

2016-04-21

Loss aversion is a decision bias, reflecting a greater sensitivity to losses than to gains in a decision situation. Recent neuroscientific research has shown that mesocorticolimbic structures like ventromedial prefrontal cortex and the ventral striatum constitute a bidirectional neural system that processes gains and losses and exhibits a neural basis of loss aversion. On a functional and structural level, the amygdala and insula also seem to play an important role in the processing of loss averse behavior. By applying voxel-based morphometry to structural brain images in N=41 healthy participants, the current study provides further evidence for the relationship of brain structure and loss aversion. The results show a negative correlation of gray matter volume in bilateral posterior insula as well as left medial frontal gyrus with individual loss aversion. Hence, higher loss aversion is associated with lower gray matter volume in these brain areas. Both structures have been discussed to play important roles in the brain's salience network, where the posterior insula is involved in interoception and the detection of salience. The medial frontal gyrus might impact decision making through its dense connections with the anterior cingulate cortex. A possible explanation for the present finding is that structural differences in these regions alter the processing of losses and salience, possibly biasing decision making towards avoidance of negative outcomes. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

a Super Voxel-Based Riemannian Graph for Multi Scale Segmentation of LIDAR Point Clouds

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Li, Minglei

2018-04-01

Automatically segmenting LiDAR points into respective independent partitions has become a topic of great importance in photogrammetry, remote sensing and computer vision. In this paper, we cast the problem of point cloud segmentation as a graph optimization problem by constructing a Riemannian graph. The scale space of the observed scene is explored by an octree-based over-segmentation with different depths. The over-segmentation produces many super voxels which restrict the structure of the scene and will be used as nodes of the graph. The Kruskal coordinates are used to compute edge weights that are proportional to the geodesic distance between nodes. Then we compute the edge-weight matrix in which the elements reflect the sectional curvatures associated with the geodesic paths between super voxel nodes on the scene surface. The final segmentation results are generated by clustering similar super voxels and cutting off the weak edges in the graph. The performance of this method was evaluated on LiDAR point clouds for both indoor and outdoor scenes. Additionally, extensive comparisons to state of the art techniques show that our algorithm outperforms on many metrics.

Spatiotemporal Gait Characteristics Associated with Cognitive Impairment: A Multicenter Cross-Sectional Study, the Intercontinental "Gait, cOgnitiOn & Decline" Initiative.

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Beauchet, Olivier; Blumen, Helena M; Callisaya, Michele L; De Cock, Anne-Marie; Kressig, Reto W; Srikanth, Velandai; Steinmetz, Jean-Paul; Verghese, Joe; Allali, Gilles

2018-01-23

The study aims to determine the spatiotemporal gait parameters and/or their combination(s) that best differentiate between cognitively healthy individuals (CHI), patients with mild cognitive impairment (MCI) and those with mild and moderate dementia, regardless of the etiology of cognitive impairment. A total of 2099 participants (1015 CHI, 478 patients with MCI, 331 patients with mild dementia and 275 with moderate dementia) were selected from the intercontinental "Gait, cOgnitiOn & Decline" (GOOD) initiative, which merged different databases from seven cross-sectional studies. Mean values and coefficients of variation (CoV) of spatiotemporal gait parameters were recorded during usual walking with the GAITRite® system. The severity of cognitive impairment was associated with worse performance on all gait parameters. Stride velocity had the strongest association with cognitive impairment, regardless of cognitive status. High mean value and CoV of stride length characterized moderate dementia, whereas increased CoV of stride time was specific to MCI status. The findings support the existence of specific cognitive impairment-related gait disturbances with differences related to stages of cognitive impairment, which may be used to screen individuals with cognitive impairment. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Gait rehabilitation machines based on programmable footplates.

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Schmidt, Henning; Werner, Cordula; Bernhardt, Rolf; Hesse, Stefan; Krüger, Jörg

2007-02-09

Gait restoration is an integral part of rehabilitation of brain lesioned patients. Modern concepts favour a task-specific repetitive approach, i.e. who wants to regain walking has to walk, while tone-inhibiting and gait preparatory manoeuvres had dominated therapy before. Following the first mobilization out of the bed, the wheelchair-bound patient should have the possibility to practise complex gait cycles as soon as possible. Steps in this direction were treadmill training with partial body weight support and most recently gait machines enabling the repetitive training of even surface gait and even of stair climbing. With treadmill training harness-secured and partially relieved wheelchair-mobilised patients could practise up to 1000 steps per session for the first time. Controlled trials in stroke and SCI patients, however, failed to show a superior result when compared to walking exercise on the floor. Most likely explanation was the effort for the therapists, e.g. manually setting the paretic limbs during the swing phase resulting in a too little gait intensity. The next steps were gait machines, either consisting of a powered exoskeleton and a treadmill (Lokomat, AutoAmbulator) or an electromechanical solution with the harness secured patient placed on movable foot plates (Gait Trainer GT I). For the latter, a large multi-centre trial with 155 non-ambulatory stroke patients (DEGAS) revealed a superior gait ability and competence in basic activities of living in the experimental group. The HapticWalker continued the end effector concept of movable foot plates, now fully programmable and equipped with 6 DOF force sensors. This device for the first time enables training of arbitrary walking situations, hence not only the simulation of floor walking but also for example of stair climbing and perturbations. Locomotor therapy is a fascinating new tool in rehabilitation, which is in line with modern principles of motor relearning promoting a task-specific repetitive

Gait rehabilitation machines based on programmable footplates

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Bernhardt Rolf

2007-02-01

Full Text Available Abstract Background Gait restoration is an integral part of rehabilitation of brain lesioned patients. Modern concepts favour a task-specific repetitive approach, i.e. who wants to regain walking has to walk, while tone-inhibiting and gait preparatory manoeuvres had dominated therapy before. Following the first mobilization out of the bed, the wheelchair-bound patient should have the possibility to practise complex gait cycles as soon as possible. Steps in this direction were treadmill training with partial body weight support and most recently gait machines enabling the repetitive training of even surface gait and even of stair climbing. Results With treadmill training harness-secured and partially relieved wheelchair-mobilised patients could practise up to 1000 steps per session for the first time. Controlled trials in stroke and SCI patients, however, failed to show a superior result when compared to walking exercise on the floor. Most likely explanation was the effort for the therapists, e.g. manually setting the paretic limbs during the swing phase resulting in a too little gait intensity. The next steps were gait machines, either consisting of a powered exoskeleton and a treadmill (Lokomat, AutoAmbulator or an electromechanical solution with the harness secured patient placed on movable foot plates (Gait Trainer GT I. For the latter, a large multi-centre trial with 155 non-ambulatory stroke patients (DEGAS revealed a superior gait ability and competence in basic activities of living in the experimental group. The HapticWalker continued the end effector concept of movable foot plates, now fully programmable and equipped with 6 DOF force sensors. This device for the first time enables training of arbitrary walking situations, hence not only the simulation of floor walking but also for example of stair climbing and perturbations. Conclusion Locomotor therapy is a fascinating new tool in rehabilitation, which is in line with modern principles

Quantification and recognition of parkinsonian gait from monocular video imaging using kernel-based principal component analysis

Directory of Open Access Journals (Sweden)

Chen Shih-Wei

2011-11-01

Full Text Available Abstract Background The computer-aided identification of specific gait patterns is an important issue in the assessment of Parkinson's disease (PD. In this study, a computer vision-based gait analysis approach is developed to assist the clinical assessments of PD with kernel-based principal component analysis (KPCA. Method Twelve PD patients and twelve healthy adults with no neurological history or motor disorders within the past six months were recruited and separated according to their "Non-PD", "Drug-On", and "Drug-Off" states. The participants were asked to wear light-colored clothing and perform three walking trials through a corridor decorated with a navy curtain at their natural pace. The participants' gait performance during the steady-state walking period was captured by a digital camera for gait analysis. The collected walking image frames were then transformed into binary silhouettes for noise reduction and compression. Using the developed KPCA-based method, the features within the binary silhouettes can be extracted to quantitatively determine the gait cycle time, stride length, walking velocity, and cadence. Results and Discussion The KPCA-based method uses a feature-extraction approach, which was verified to be more effective than traditional image area and principal component analysis (PCA approaches in classifying "Non-PD" controls and "Drug-Off/On" PD patients. Encouragingly, this method has a high accuracy rate, 80.51%, for recognizing different gaits. Quantitative gait parameters are obtained, and the power spectrums of the patients' gaits are analyzed. We show that that the slow and irregular actions of PD patients during walking tend to transfer some of the power from the main lobe frequency to a lower frequency band. Our results indicate the feasibility of using gait performance to evaluate the motor function of patients with PD. Conclusion This KPCA-based method requires only a digital camera and a decorated corridor setup

Wavelet-based characterization of gait signal for neurological abnormalities.

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Baratin, E; Sugavaneswaran, L; Umapathy, K; Ioana, C; Krishnan, S

2015-02-01

Studies conducted by the World Health Organization (WHO) indicate that over one billion suffer from neurological disorders worldwide, and lack of efficient diagnosis procedures affects their therapeutic interventions. Characterizing certain pathologies of motor control for facilitating their diagnosis can be useful in quantitatively monitoring disease progression and efficient treatment planning. As a suitable directive, we introduce a wavelet-based scheme for effective characterization of gait associated with certain neurological disorders. In addition, since the data were recorded from a dynamic process, this work also investigates the need for gait signal re-sampling prior to identification of signal markers in the presence of pathologies. To benefit automated discrimination of gait data, certain characteristic features are extracted from the wavelet-transformed signals. The performance of the proposed approach was evaluated using a database consisting of 15 Parkinson's disease (PD), 20 Huntington's disease (HD), 13 Amyotrophic lateral sclerosis (ALS) and 16 healthy control subjects, and an average classification accuracy of 85% is achieved using an unbiased cross-validation strategy. The obtained results demonstrate the potential of the proposed methodology for computer-aided diagnosis and automatic characterization of certain neurological disorders. Copyright © 2015 Elsevier B.V. All rights reserved.

Voxel Based Analysis of Surgical Revascularization for Moyamoya Disease: Pre- and Postoperative SPECT Studies.

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Yasutaka Fushimi

Full Text Available Moyamoya disease (MMD is a chronic, progressive, cerebrovascular occlusive disease that causes abnormal enlargement of collateral pathways (moyamoya vessels in the region of the basal ganglia and thalamus. Cerebral revascularization procedures remain the preferred treatment for patients with MMD, improving the compromised cerebral blood flow (CBF. However, voxel based analysis (VBA of revascularization surgery for MMD based on data from pre- and postoperative data has not been established. The latest algorithm called as Diffeomorphic Anatomical Registration Through Exponentiated Lie Algebra (DARTEL has been introduced for VBA as the function of statistical parametric mapping (SPM8, and improved registration has been achieved by SPM8 with DARTEL. In this study, VBA was conducted to evaluate pre- and postoperative single photon emission computed tomography (SPECT images for MMD by SPM8 with DARTEL algorithm, and the results were compared with those from SPM8 without DARTEL (a conventional method. Thirty-two patients with MMD who underwent superficial temporal artery-middle cerebral artery (STA-MCA bypass surgery as the first surgery were included and all patients underwent pre- and postoperative 3D T1-weighted imaging and SPECT. Pre- and postoperative SPECT images were registered to 3D T1-weighted images, then VBA was conducted. Postoperative SPECT showed more statistically increased CBF areas in the bypassed side cerebral hemisphere by using SPM8 with DARTEL (58,989 voxels; P<0.001, and increased ratio of CBF after operation was less than 15%. Meanwhile, postoperative SPECT showed less CBF increased areas by SPM8 without DARTEL. In conclusion, VBA was conducted for patients with MMD, and SPM8 with DARTEL revealed that postoperative SPECT showed statistically significant CBF increases over a relatively large area and with at most 15% increase ratio.

A Portable Gait Asymmetry Rehabilitation System for Individuals with Stroke Using a Vibrotactile Feedback

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Muhammad Raheel Afzal

2015-01-01

Full Text Available Gait asymmetry caused by hemiparesis results in reduced gait efficiency and reduced activity levels. In this paper, a portable rehabilitation device is proposed that can serve as a tool in diagnosing gait abnormalities in individuals with stroke and has the capability of providing vibration feedback to help compensate for the asymmetric gait. Force-sensitive resistor (FSR based insoles are used to detect ground contact and estimate stance time. A controller (Arduino provides different vibration feedback based on the gait phase measurement. It also allows wireless interaction with a personal computer (PC workstation using the XBee transceiver module, featuring data logging capabilities for subsequent analysis. Walking trials conducted with healthy young subjects allowed us to observe that the system can influence abnormality in the gait. The results of trials showed that a vibration cue based on temporal information was more effective than intensity information. With clinical experiments conducted for individuals with stroke, significant improvement in gait symmetry was observed with minimal disturbance caused to the balance and gait speed as an effect of the biofeedback. Future studies of the long-term rehabilitation effects of the proposed system and further improvements to the system will result in an inexpensive, easy-to-use, and effective rehabilitation device.

Gray and white matter asymmetries in healthy individuals aged 21-29 years: a voxel-based morphometry and diffusion tensor imaging study.

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Takao, Hidemasa; Abe, Osamu; Yamasue, Hidenori; Aoki, Shigeki; Sasaki, Hiroki; Kasai, Kiyoto; Yoshioka, Naoki; Ohtomo, Kuni

2011-10-01

The hemispheres of the human brain are functionally and structurally asymmetric. The study of structural asymmetries provides important clues to the neuroanatomical basis of lateralized brain functions. Previous studies have demonstrated age-related changes in morphology and diffusion properties of brain tissue. In this study, we simultaneously explored gray and white matter asymmetry using voxel-based morphometry (VBM) and diffusion tensor imaging (DTI) in 109 young healthy individuals (58 females and 51 males). To eliminate the potential confounding effects of aging and handedness, we restricted the study to right-handed subjects aged 21-29 years. VBM and voxel-based analysis of fractional anisotropy (FA) maps derived from DTI revealed a number of gray matter volume asymmetries (including the right frontal and left occipital petalias and leftward asymmetry of the planum temporale) and white matter FA asymmetries (including leftward asymmetry of the arcuate fasciculus, cingulum, and corticospinal tract). There was no significant effect of sex on gray and white matter asymmetry. Leftward volume asymmetry of the planum temporale and leftward FA asymmetry of the arcuate fasciculus were simultaneously demonstrated. Post hoc analysis showed that the gray matter volume of the planum temporale and FA of the arcuate fasciculus were positively related (Pearson correlation coefficient, 0.43; P < 0.0001). The results of our study demonstrate gray and white matter asymmetry in right-handed healthy young adults and suggest that leftward volume asymmetry of the planum temporale and leftward FA asymmetry of the arcuate fasciculus may be related. Copyright © 2010 Wiley-Liss, Inc.

Mobile Phone-Based Measures of Activity, Step Count, and Gait Speed: Results From a Study of Older Ambulatory Adults in a Naturalistic Setting.

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Rye Hanton, Cassia; Kwon, Yong-Jun; Aung, Thawda; Whittington, Jackie; High, Robin R; Goulding, Evan H; Schenk, A Katrin; Bonasera, Stephen J

2017-10-03

Cellular mobile telephone technology shows much promise for delivering and evaluating healthcare interventions in cost-effective manners with minimal barriers to access. There is little data demonstrating that these devices can accurately measure clinically important aspects of individual functional status in naturalistic environments outside of the laboratory. The objective of this study was to demonstrate that data derived from ubiquitous mobile phone technology, using algorithms developed and previously validated by our lab in a controlled setting, can be employed to continuously and noninvasively measure aspects of participant (subject) health status including step counts, gait speed, and activity level, in a naturalistic community setting. A second objective was to compare our mobile phone-based data against current standard survey-based gait instruments and clinical physical performance measures in order to determine whether they measured similar or independent constructs. A total of 43 ambulatory, independently dwelling older adults were recruited from Nebraska Medicine, including 25 (58%, 25/43) healthy control individuals from our Engage Wellness Center and 18 (42%, 18/43) functionally impaired, cognitively intact individuals (who met at least 3 of 5 criteria for frailty) from our ambulatory Geriatrics Clinic. The following previously-validated surveys were obtained on study day 1: (1) Late Life Function and Disability Instrument (LLFDI); (2) Survey of Activities and Fear of Falling in the Elderly (SAFFE); (3) Patient Reported Outcomes Measurement Information System (PROMIS), short form version 1.0 Physical Function 10a (PROMIS-PF); and (4) PROMIS Global Health, short form version 1.1 (PROMIS-GH). In addition, clinical physical performance measurements of frailty (10 foot Get up and Go, 4 Meter walk, and Figure-of-8 Walk [F8W]) were also obtained. These metrics were compared to our mobile phone-based metrics collected from the participants in the community

Voxel-based lesion analysis of brain regions underlying reading and writing.

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Baldo, Juliana V; Kacinik, Natalie; Ludy, Carl; Paulraj, Selvi; Moncrief, Amber; Piai, Vitória; Curran, Brian; Turken, And; Herron, Tim; Dronkers, Nina F

2018-03-20

The neural basis of reading and writing has been a source of inquiry as well as controversy in the neuroscience literature. Reading has been associated with both left posterior ventral temporal zones (termed the "visual word form area") as well as more dorsal zones, primarily in left parietal cortex. Writing has also been associated with left parietal cortex, as well as left sensorimotor cortex and prefrontal regions. Typically, the neural basis of reading and writing are examined in separate studies and/or rely on single case studies exhibiting specific deficits. Functional neuroimaging studies of reading and writing typically identify a large number of activated regions but do not necessarily identify the core, critical hubs. Last, due to constraints on the functional imaging environment, many previous studies have been limited to measuring the brain activity associated with single-word reading and writing, rather than sentence-level processing. In the current study, the brain correlates of reading and writing at both the single- and sentence-level were studied in a large sample of 111 individuals with a history of chronic stroke using voxel-based lesion symptom mapping (VLSM). VLSM provides a whole-brain, voxel-by-voxel statistical analysis of the role of distinct regions in a particular behavior by comparing performance of individuals with and without a lesion at every voxel. Rather than comparing individual cases or small groups with particular behavioral dissociations in reading and writing, VLSM allowed us to analyze data from a large, well-characterized sample of stroke patients exhibiting a wide range of reading and writing impairments. The VLSM analyses revealed that reading was associated with a critical left inferior temporo-occipital focus, while writing was primarily associated with the left supramarginal gyrus. Separate VLSM analyses of single-word versus sentence-level reading showed that sentence-level reading was uniquely associated with anterior

Comparison of grey matter and metabolic reductions in frontotemporal dementia using FDG-PET and voxel-based morphometric MR studies

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Kanda, Tomonori; Uemura, Takafumi; Miyamoto, Naokazu; Yoshikawa, Toshiki; Kono, Atsushi K. [Hyogo Brain and Heart Center, Department of Radiology and Nuclear Medicine, Himeji, Hyogo (Japan); Ishii, Kazunari [Hyogo Brain and Heart Center, Department of Radiology and Nuclear Medicine, Himeji, Hyogo (Japan); Hyogo Institute for Aging Brain and Cognitive Disorders, Division of Neuroimaging Research, Himeji, Hyogo (Japan); Mori, Etsuro [Hyogo Institute for Aging Brain and Cognitive Disorders, Division of Clinical Neurosciences, Himeji, Hyogo (Japan); Tohoku University Graduate School of Medicine, Behavioral Neurology and Cognitive Neuroscience, Sendai, Miyagi (Japan)

2008-12-15

The aim of this study was to investigate the regional differences between the morphologic and functional changes in the same patients with frontotemporal dementia (FTD) using statistical parametric mapping and voxel-based morphometry (VBM). Thirteen FTD patients (mean age, 64.9 years old; mean MMSE score, 17.7), 20 sex-matched Alzheimer's disease (AD) patients (mean age, 65.0 years old; mean MMSE score, 17.5), and 20 normal volunteers (mean age, 65.2 years old; mean MMSE score, 29.0) underwent both [{sup 18}F]FDG positron emission tomography and three-dimensional spoiled gradient echo MRI. Statistical parametric mapping was used to conduct a VBM analysis of the morphologic data, which were compared voxel by voxel with the results of a similar analysis of glucose metabolic data. FTD patients showed decreased grey matter volume and decreased glucose metabolism in the frontal lobe and anterior temporal lobe. In addition, there was a clear asymmetry in grey matter volume in FTD patients by the VBM analysis while the glucose metabolic data showed little asymmetry. In AD patients, glucose metabolic reduction occurred in the bilateral posterior cingulate gyri and parietal lobules while grey matter density decreased the least in the same patients. In FTD, metabolic and morphologic changes occur in the bilateral frontal lobe and temporal lobe with a limited asymmetry whereas there was considerable discordance in the AD group. (orig.)

Validation of voxel-based morphometry (VBM) based on MRI

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Yang, Xueyu; Chen, Kewei; Guo, Xiaojuan; Yao, Li

2007-03-01

Voxel-based morphometry (VBM) is an automated and objective image analysis technique for detecting differences in regional concentration or volume of brain tissue composition based on structural magnetic resonance (MR) images. VBM has been used widely to evaluate brain morphometric differences between different populations, but there isn't an evaluation system for its validation until now. In this study, a quantitative and objective evaluation system was established in order to assess VBM performance. We recruited twenty normal volunteers (10 males and 10 females, age range 20-26 years, mean age 22.6 years). Firstly, several focal lesions (hippocampus, frontal lobe, anterior cingulate, back of hippocampus, back of anterior cingulate) were simulated in selected brain regions using real MRI data. Secondly, optimized VBM was performed to detect structural differences between groups. Thirdly, one-way ANOVA and post-hoc test were used to assess the accuracy and sensitivity of VBM analysis. The results revealed that VBM was a good detective tool in majority of brain regions, even in controversial brain region such as hippocampus in VBM study. Generally speaking, much more severity of focal lesion was, better VBM performance was. However size of focal lesion had little effects on VBM analysis.

Voxel-based Monte Carlo simulation of X-ray imaging and spectroscopy experiments

International Nuclear Information System (INIS)

Bottigli, U.; Brunetti, A.; Golosio, B.; Oliva, P.; Stumbo, S.; Vincze, L.; Randaccio, P.; Bleuet, P.; Simionovici, A.; Somogyi, A.

2004-01-01

A Monte Carlo code for the simulation of X-ray imaging and spectroscopy experiments in heterogeneous samples is presented. The energy spectrum, polarization and profile of the incident beam can be defined so that X-ray tube systems as well as synchrotron sources can be simulated. The sample is modeled as a 3D regular grid. The chemical composition and density is given at each point of the grid. Photoelectric absorption, fluorescent emission, elastic and inelastic scattering are included in the simulation. The core of the simulation is a fast routine for the calculation of the path lengths of the photon trajectory intersections with the grid voxels. The voxel representation is particularly useful for samples that cannot be well described by a small set of polyhedra. This is the case of most naturally occurring samples. In such cases, voxel-based simulations are much less expensive in terms of computational cost than simulations on a polygonal representation. The efficient scheme used for calculating the path lengths in the voxels and the use of variance reduction techniques make the code suitable for the detailed simulation of complex experiments on generic samples in a relatively short time. Examples of applications to X-ray imaging and spectroscopy experiments are discussed

Voxel-based Monte Carlo simulation of X-ray imaging and spectroscopy experiments

Energy Technology Data Exchange (ETDEWEB)

Bottigli, U. [Istituto di Matematica e Fisica dell' Universita di Sassari, via Vienna 2, 07100, Sassari (Italy); Sezione INFN di Cagliari (Italy); Brunetti, A. [Istituto di Matematica e Fisica dell' Universita di Sassari, via Vienna 2, 07100, Sassari (Italy); Golosio, B. [Istituto di Matematica e Fisica dell' Universita di Sassari, via Vienna 2, 07100, Sassari (Italy) and Sezione INFN di Cagliari (Italy)]. E-mail: golosio@uniss.it; Oliva, P. [Istituto di Matematica e Fisica dell' Universita di Sassari, via Vienna 2, 07100, Sassari (Italy); Stumbo, S. [Istituto di Matematica e Fisica dell' Universita di Sassari, via Vienna 2, 07100, Sassari (Italy); Vincze, L. [Department of Chemistry, University of Antwerp (Belgium); Randaccio, P. [Dipartimento di Fisica dell' Universita di Cagliari and Sezione INFN di Cagliari (Italy); Bleuet, P. [European Synchrotron Radiation Facility, Grenoble (France); Simionovici, A. [European Synchrotron Radiation Facility, Grenoble (France); Somogyi, A. [European Synchrotron Radiation Facility, Grenoble (France)

2004-10-08

A Monte Carlo code for the simulation of X-ray imaging and spectroscopy experiments in heterogeneous samples is presented. The energy spectrum, polarization and profile of the incident beam can be defined so that X-ray tube systems as well as synchrotron sources can be simulated. The sample is modeled as a 3D regular grid. The chemical composition and density is given at each point of the grid. Photoelectric absorption, fluorescent emission, elastic and inelastic scattering are included in the simulation. The core of the simulation is a fast routine for the calculation of the path lengths of the photon trajectory intersections with the grid voxels. The voxel representation is particularly useful for samples that cannot be well described by a small set of polyhedra. This is the case of most naturally occurring samples. In such cases, voxel-based simulations are much less expensive in terms of computational cost than simulations on a polygonal representation. The efficient scheme used for calculating the path lengths in the voxels and the use of variance reduction techniques make the code suitable for the detailed simulation of complex experiments on generic samples in a relatively short time. Examples of applications to X-ray imaging and spectroscopy experiments are discussed.

Gray Matter Atrophy within the Default Mode Network of Fibromyalgia: A Meta-Analysis of Voxel-Based Morphometry Studies

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Chemin Lin

2016-01-01

Full Text Available Over the years, studies have demonstrated morphological changes in the brain of fibromyalgia (FMS. We aimed to conduct a coordinate-based meta-analytic research through systemic review on voxel-based morphometry (VBM imaging results to identify consistent gray matter (GM difference between FMS patients and healthy subjects. We performed a comprehensive literature search in PubMed (January 2000–December 2015 and included six VBM publication on FMS. Stereotactic data were extracted from 180 patients of FMS and 123 healthy controls. By means of activation likelihood estimation (ALE technique, regional GM reduction in left medial prefrontal cortex and right dorsal posterior cingulate cortex was identified. Both regions are within the default mode network. In conclusion, the gray matter deficit is related to the both affective and nonaffective components of pain processing. This result also provided the neuroanatomical correlates for emotional and cognitive symptoms in FMS.

Study on the Construction of a High-definition Whole-body Voxel Model based on Cadaver's Color Photographic Anatomical Slice Images and Monte Carlo Dose Calculations

International Nuclear Information System (INIS)

Choi, Sang Hyoun

2007-08-01

Ajou University School of Medicine made the serially sectioned anatomical images from the Visible Korean Human (VKH) Project in Korea. The VKH images, which are the high-resolution color photographic images, show the organs and tissues in the human body very clearly at 0.2 mm intervals. In this study, we constructed a high-quality voxel model (VKH-Man) with a total of 30 organs and tissues by manual and automatic segmentation method using the serially sectioned anatomical image data from the Visible Korean Human (VKH) project in Korea. The height and weight of VKH-Man voxel model is 164 cm and 57.6 kg, respectively, and the voxel resolution is 1.875 x 1.875 x 2 mm 3 . However, this voxel phantom can be used to calculate the organ and tissue doses of only one person. Therefore, in this study, we adjusted the voxel phantom to the 'Reference Korean' data to construct the voxel phantom that represents the radiation workers in Korea. The height and weight of the voxel model (HDRK-Man) that is finally developed are 171 cm and 68 kg, respectively, and the voxel resolution is 1.981 x 1.981 x 2.0854 mm 3 . VKH-Man and HDRK-Man voxel model were implemented in a Monte Carlo particle transport simulation code for calculation of the organ and tissue doses in various irradiation geometries. The calculated values were compared with each other to see the effect of the adjustment and also compared with other computational models (KTMAN-2, ICRP-74 and VIP-Man). According to the results, the adjustment of the voxel model was found hardly affect the dose calculations and most of the organ and tissue equivalent doses showed some differences among the models. These results shows that the difference in figure, and organ topology affects the organ doses more than the organ size. The calculated values of the effective dose from VKH-Man and HDRK-Man according to the ICRP-60 and upcoming ICRP recommendation were compared. For the other radiation geometries (AP, LLAT, RLAT) except for PA

Gait Selection and Transition of Passivity-Based Bipeds with Adaptable Ankle Stiffness

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Yan Huang

2012-10-01

Full Text Available Stable bipedal walking is one of the most important components of humanoid robot design, which can help us better understand natural human walking. In this paper, to study gait selection and gait transition of efficient bipedal walking, we proposed a dynamic bipedal walking model with an upper body, flat feet and compliant joints. The model can achieve stable cyclic motion with different walking gaits. The hip actuation and ankle stiffness behavior of the model are quite similar to those of human normal walking. In simulation, we studied the influence of hip actuation and ankle stiffness on walking performance of each gait. The effects of ankle stiffness on gait selection are also analyzed. Gait transition is realized by adjusting ankle stiffness during walking.

Behavioral Inhibition System activity is associated with increased amygdala and hippocampal gray matter volume: A voxel-based morphometry study.

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Barrós-Loscertales, A; Meseguer, V; Sanjuán, A; Belloch, V; Parcet, M A; Torrubia, R; Avila, C

2006-11-15

Recent research has examined anxiety and hyperactivity in the amygdala and the anterior hippocampus while processing aversive stimuli. In order to determine whether these functional differences have a structural basis, optimized voxel-based morphometry was used to study the relationship between gray matter concentration in the brain and scores on a Behavioral Inhibition System measure (the Sensitivity to Punishment scale) in a sample of 63 male undergraduates. Results showed a positive correlation between Sensitivity to Punishment scores and gray matter volume in the amygdala and the hippocampal formation, that is, in areas that Gray, J.A., and McNaughton, N.J. (2000). The neuropsychology of anxiety. Oxford: Oxford Medical Publications. associated with the Behavioral Inhibition System.

A mechanized gait trainer for restoring gait in nonambulatory subjects.

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Hesse, S; Uhlenbrock, D; Werner, C; Bardeleben, A

2000-09-01

To construct an advanced mechanized gait trainer to enable patients the repetitive practice of a gaitlike movement without overstraining therapists. DEVICE: Prototype gait trainer that simulates the phases of gait (by generating a ratio of 40% to 60% between swing and stance phases), supports the subjects according to their ability (lifts the foot during swing phase), and controls the center of mass in the vertical and horizontal directions. Two nonambulatory, hemiparetic patients who regained their walking ability after 4 weeks of daily training on the gait trainer, a 55-year-old woman and a 62-year-old man, both of whom had a first-time ischemic stroke. Four weeks of training, five times a week, each session 20 minutes long. Functional ambulation category (FAC, levels 0-5) to assess gait ability and ground level walking velocity. Rivermead motor assessment score (RMAS, 0-13) to assess gross motor function. Patient 1: At the end of treatment, she was able to walk independently on level ground with use of a walking stick. Her walking velocity had improved from .29m/sec to .59m/sec. Her RMAS score increased from 4 to 10, meaning she could walk at least 40 meters outside, pick up objects from floor, and climb stairs independently. Patient 2: At end of 4-week training, he could walk independently on even surfaces (FAC level 4), using an ankle-foot orthosis and a walking stick. His walking velocity improved from .14m/sec to .63m/sec. His RMAS increased from 3 to 10. The gait trainer enabled severely affected patients the repetitive practice of a gaitlike movement. Future studies may elucidate its value in gait rehabilitation of nonambulatory subjects.

Voxel based statistical analysis method for microPET studies to assess the cerebral glucose metabolism in cat deafness model: comparison to ROI based method

International Nuclear Information System (INIS)

Kim, Jin Su; Lee, Jae Sung; Park, Min Hyun; Lee, Jong Jin; Kang, Hye Jin; Lee, Hyo Jeong; Oh, Seung Ha; Kim, Chong Sun; Jung, June Key; Lee, Myung Chul; Lee, Dong Soo; Lim, Sang Moo

2005-01-01

Imaging research on the brain of sensory-deprived cats using small animal PET scanner has gained interest since the abundant information about the sensory system of ths animal is available and close examination of the brain is possible due to larger size of its brain than mouse or rat. In this study, we have established the procedures for 3D voxel-based statistical analysis (SPM) of FDG PET image of cat brain, and confirmed using ROI based-method. FDG PET scans of 4 normal and 4 deaf cats were acquired for 30 minutes using microPET R4 scanner. Only the brain cortices were extracted using a masking and threshold method to facilitate spatial normalization. After spatial normalization and smoothing, 3D voxel-wise and ROI based t-test were performed to identify the regions with significant different FDG uptake between the normal and deaf cats. In ROI analysis, 26 ROIs were drawn on both hemispheres, and regional mean pixel value in each ROI was normalized to the global mean of the brain. Cat brains were spatially normalized well onto the target brain due to the removal of background activity. When cerebral glucose metabolism of deaf cats were compared to the normal controls after removing the effects of the global count, the glucose metabolism in the auditory cortex, head of caudate nucleus, and thalamus in both hemispheres of the deaf cats was significantly lower than that of the controls (P<0.01). No area showed a significantly increased metabolism in the deaf cats even in higher significance level (P<0.05). ROI analysis also showed significant reduction of glucose metabolism in the same region. This study established and confirmed a method for voxel-based analysis of animal PET data of cat brain, which showed high localization accuracy and specificity and was useful for examining the cerebral glucose metabolism in a cat cortical deafness model

Voxel based statistical analysis method for microPET studies to assess the cerebral glucose metabolism in cat deafness model: comparison to ROI based method

Energy Technology Data Exchange (ETDEWEB)

Kim, Jin Su; Lee, Jae Sung; Park, Min Hyun; Lee, Jong Jin; Kang, Hye Jin; Lee, Hyo Jeong; Oh, Seung Ha; Kim, Chong Sun; Jung, June Key; Lee, Myung Chul; Lee, Dong Soo [Seoul National University College of Medicine, Seoul (Korea, Republic of); Lim, Sang Moo [KIRAMS, Seoul (Korea, Republic of)

2005-07-01

Imaging research on the brain of sensory-deprived cats using small animal PET scanner has gained interest since the abundant information about the sensory system of ths animal is available and close examination of the brain is possible due to larger size of its brain than mouse or rat. In this study, we have established the procedures for 3D voxel-based statistical analysis (SPM) of FDG PET image of cat brain, and confirmed using ROI based-method. FDG PET scans of 4 normal and 4 deaf cats were acquired for 30 minutes using microPET R4 scanner. Only the brain cortices were extracted using a masking and threshold method to facilitate spatial normalization. After spatial normalization and smoothing, 3D voxel-wise and ROI based t-test were performed to identify the regions with significant different FDG uptake between the normal and deaf cats. In ROI analysis, 26 ROIs were drawn on both hemispheres, and regional mean pixel value in each ROI was normalized to the global mean of the brain. Cat brains were spatially normalized well onto the target brain due to the removal of background activity. When cerebral glucose metabolism of deaf cats were compared to the normal controls after removing the effects of the global count, the glucose metabolism in the auditory cortex, head of caudate nucleus, and thalamus in both hemispheres of the deaf cats was significantly lower than that of the controls (P<0.01). No area showed a significantly increased metabolism in the deaf cats even in higher significance level (P<0.05). ROI analysis also showed significant reduction of glucose metabolism in the same region. This study established and confirmed a method for voxel-based analysis of animal PET data of cat brain, which showed high localization accuracy and specificity and was useful for examining the cerebral glucose metabolism in a cat cortical deafness model.

A longitudinal study on dual-tasking effects on gait: cognitive change predicts gait variance in the elderly.

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Rebecca K MacAulay

Full Text Available Neuropsychological abilities have found to explain a large proportion of variance in objective measures of walking gait that predict both dementia and falling within the elderly. However, to this date there has been little research on the interplay between changes in these neuropsychological processes and walking gait overtime. To our knowledge, the present study is the first to investigate intra-individual changes in neurocognitive test performance and gait step time at two-time points across a one-year span. Neuropsychological test scores from 440 elderly individuals deemed cognitively normal at Year One were analyzed via repeated measures t-tests to assess for decline in cognitive performance at Year Two. 34 of these 440 individuals neuropsychological test performance significantly declined at Year Two; whereas the "non-decliners" displayed improved memory, working memory, attention/processing speed test performance. Neuropsychological test scores were also submitted to factor analysis at both time points for data reduction purposes and to assess the factor stability overtime. Results at Year One yielded a three-factor solution: Language/Memory, Executive Attention/Processing Speed, and Working Memory. Year Two's test scores also generated a three-factor solution (Working Memory, Language/Executive Attention/Processing Speed, and Memory. Notably, language measures loaded on Executive Attention/Processing Speed rather than on the Memory factor at Year Two. Hierarchal multiple regression revealed that both Executive Attention/Processing Speed and sex significantly predicted variance in dual task step time at both time points. Remarkably, in the "decliners", the magnitude of the contribution of the neuropsychological characteristics to gait variance significantly increased at Year Two. In summary, this study provides longitudinal evidence of the dynamic relationship between intra-individual cognitive change and its influence on dual task gait

A Voxel-Based Approach to Explore Local Dose Differences Associated With Radiation-Induced Lung Damage

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Palma, Giuseppe [Institute of Biostructure and Bioimaging, National Research Council, Naples (Italy); Monti, Serena [IRCCS SDN, Naples (Italy); D' Avino, Vittoria [Institute of Biostructure and Bioimaging, National Research Council, Naples (Italy); Conson, Manuel [Institute of Biostructure and Bioimaging, National Research Council, Naples (Italy); Department of Advanced Biomedical Sciences, Federico II University School of Medicine, Naples (Italy); Liuzzi, Raffaele [Institute of Biostructure and Bioimaging, National Research Council, Naples (Italy); Pressello, Maria Cristina [Department of Health Physics, S. Camillo-Forlanini Hospital, Rome (Italy); Donato, Vittorio [Department of Radiation Oncology, S. Camillo-Forlanini Hospital, Rome (Italy); Deasy, Joseph O. [Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, NY (United States); Quarantelli, Mario [Institute of Biostructure and Bioimaging, National Research Council, Naples (Italy); Pacelli, Roberto [Institute of Biostructure and Bioimaging, National Research Council, Naples (Italy); Department of Advanced Biomedical Sciences, Federico II University School of Medicine, Naples (Italy); Cella, Laura, E-mail: laura.cella@cnr.it [Institute of Biostructure and Bioimaging, National Research Council, Naples (Italy)

2016-09-01

Purpose: To apply a voxel-based (VB) approach aimed at exploring local dose differences associated with late radiation-induced lung damage (RILD). Methods and Materials: An interinstitutional database of 98 patients who were Hodgkin lymphoma (HL) survivors treated with postchemotherapy supradiaphragmatic radiation therapy was analyzed in the study. Eighteen patients experienced late RILD, classified according to the Radiation Therapy Oncology Group scoring system. Each patient's computed tomographic (CT) scan was normalized to a single reference case anatomy (common coordinate system, CCS) through a log-diffeomorphic approach. The obtained deformation fields were used to map the dose of each patient into the CCS. The coregistration robustness and the dose mapping accuracy were evaluated by geometric and dose scores. Two different statistical mapping schemes for nonparametric multiple permutation inference on dose maps were applied, and the corresponding P<.05 significance lung subregions were generated. A receiver operating characteristic (ROC)-based test was performed on the mean dose extracted from each subregion. Results: The coregistration process resulted in a geometrically robust and accurate dose warping. A significantly higher dose was consistently delivered to RILD patients in voxel clusters near the peripheral medial-basal portion of the lungs. The area under the ROC curves (AUC) from the mean dose of the voxel clusters was higher than the corresponding AUC derived from the total lung mean dose. Conclusions: We implemented a framework including a robust registration process and a VB approach accounting for the multiple comparison problem in dose-response modeling, and applied it to a cohort of HL survivors to explore a local dose–RILD relationship in the lungs. Patients with RILD received a significantly greater dose in parenchymal regions where low doses (∼6 Gy) were delivered. Interestingly, the relation between differences in the high

Segmentation of Gait Sequences in Sensor-Based Movement Analysis: A Comparison of Methods in Parkinson’s Disease

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Nooshin Haji Ghassemi

2018-01-01

Full Text Available Robust gait segmentation is the basis for mobile gait analysis. A range of methods have been applied and evaluated for gait segmentation of healthy and pathological gait bouts. However, a unified evaluation of gait segmentation methods in Parkinson’s disease (PD is missing. In this paper, we compare four prevalent gait segmentation methods in order to reveal their strengths and drawbacks in gait processing. We considered peak detection from event-based methods, two variations of dynamic time warping from template matching methods, and hierarchical hidden Markov models (hHMMs from machine learning methods. To evaluate the methods, we included two supervised and instrumented gait tests that are widely used in the examination of Parkinsonian gait. In the first experiment, a sequence of strides from instructed straight walks was measured from 10 PD patients. In the second experiment, a more heterogeneous assessment paradigm was used from an additional 34 PD patients, including straight walks and turning strides as well as non-stride movements. The goal of the latter experiment was to evaluate the methods in challenging situations including turning strides and non-stride movements. Results showed no significant difference between the methods for the first scenario, in which all methods achieved an almost 100% accuracy in terms of F-score. Hence, we concluded that in the case of a predefined and homogeneous sequence of strides, all methods can be applied equally. However, in the second experiment the difference between methods became evident, with the hHMM obtaining a 96% F-score and significantly outperforming the other methods. The hHMM also proved promising in distinguishing between strides and non-stride movements, which is critical for clinical gait analysis. Our results indicate that both the instrumented test procedure and the required stride segmentation algorithm have to be selected adequately in order to support and complement classical

Rotating and translating anthropomorphic head voxel models to establish an horizontal Frankfort plane for dental CBCT Monte Carlo simulations: a dose comparison study

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Stratis, A.; Zhang, G.; Jacobs, R.; Bogaerts, R.; Bosmans, H.

2016-12-01

In order to carry out Monte Carlo (MC) dosimetry studies, voxel phantoms, modeling human anatomy, and organ-based segmentation of CT image data sets are applied to simulation frameworks. The resulting voxel phantoms preserve patient CT acquisition geometry; in the case of head voxel models built upon head CT images, the head support with which CT scanners are equipped introduces an inclination to the head, and hence to the head voxel model. In dental cone beam CT (CBCT) imaging, patients are always positioned in such a way that the Frankfort line is horizontal, implying that there is no head inclination. The orientation of the head is important, as it influences the distance of critical radiosensitive organs like the thyroid and the esophagus from the x-ray tube. This work aims to propose a procedure to adjust head voxel phantom orientation, and to investigate the impact of head inclination on organ doses in dental CBCT MC dosimetry studies. The female adult ICRP, and three in-house-built paediatric voxel phantoms were in this study. An EGSnrc MC framework was employed to simulate two commonly used protocols; a Morita Accuitomo 170 dental CBCT scanner (FOVs: 60  ×  60 mm2 and 80  ×  80 mm2, standard resolution), and a 3D Teeth protocol (FOV: 100  ×  90 mm2) in a Planmeca Promax 3D MAX scanner. Result analysis revealed large absorbed organ dose differences in radiosensitive organs between the original and the geometrically corrected voxel models of this study, ranging from  -45.6% to 39.3%. Therefore, accurate dental CBCT MC dose calculations require geometrical adjustments to be applied to head voxel models.

Grey matter volume differences associated with gender in children with attention-deficit/hyperactivity disorder: A voxel-based morphometry study

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Thomas Villemonteix

2015-08-01

Full Text Available Female participants have been underrepresented in previous structural magnetic resonance imaging reports on attention-deficit/hyperactivity disorder (ADHD. In this study, we used optimized voxel-based morphometry to examine grey matter volumes in a sample of 33 never-medicated children with combined-type ADHD and 27 typically developing (TD children. We found a gender-by-diagnosis interaction effect in the ventral anterior cingulate cortex (ACC, whereby boys with ADHD exhibited reduced volumes compared with TD boys, while girls with ADHD showed increased volumes when compared with TD girls. Considering the key role played by the ventral ACC in emotional regulation, we discuss the potential contribution of these alterations to gender-specific symptoms’ profiles in ADHD.

Larger right posterior parietal volume in action video game experts: a behavioral and voxel-based morphometry (VBM study.

Directory of Open Access Journals (Sweden)

Satoshi Tanaka

Full Text Available Recent studies suggest that action video game players exhibit superior performance in visuospatial cognitive tasks compared with non-game players. However, the neural basis underlying this visuospatial cognitive performance advantage remains largely unknown. The present human behavioral and imaging study compared gray matter volume in action video game experts and non-experts using structural magnetic resonance imaging and voxel-based morphometry analysis. The results revealed significantly larger gray matter volume in the right posterior parietal cortex in experts compared with non-experts. Furthermore, the larger gray matter volume in the right posterior parietal cortex significantly correlated with individual performance in a visual working memory task in experts. These results suggest that differences in brain structure may be linked to extensive video game play, leading to superior visuospatial cognitive performance in action video game experts.

Capability of 2 gait measures for detecting response to gait training in stroke survivors: Gait Assessment and Intervention Tool and the Tinetti Gait Scale.

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Zimbelman, Janice; Daly, Janis J; Roenigk, Kristen L; Butler, Kristi; Burdsall, Richard; Holcomb, John P

2012-01-01

To characterize the performance of 2 observational gait measures, the Tinetti Gait Scale (TGS) and the Gait Assessment and Intervention Tool (G.A.I.T.), in identifying improvement in gait in response to gait training. In secondary analysis from a larger study of multimodal gait training for stroke survivors, we measured gait at pre-, mid-, and posttreatment according to G.A.I.T. and TGS, assessing their capability to capture recovery of coordinated gait components. Large medical center. Cohort of stroke survivors (N=44) greater than 6 months after stroke. All subjects received 48 sessions of a multimodal gait-training protocol. Treatment consisted of 1.5 hours per session, 4 sessions per week for 12 weeks, receiving these 3 treatment aspects: (1) coordination exercise, (2) body weight-supported treadmill training, and (3) overground gait training, with 46% of subjects receiving functional electrical stimulation. All subjects were evaluated with the G.A.I.T. and TGS before and after completing the 48-session intervention. An additional evaluation was performed at midtreatment (after session 24). For the total subject sample, there were significant pre-/post-, pre-/mid-, and mid-/posttreatment gains for both the G.A.I.T. and the TGS. According to the G.A.I.T., 40 subjects (91%) showed improved scores, 2 (4%) no change, and 2 (4%) a worsening score. According to the TGS, only 26 subjects (59%) showed improved scores, 16 (36%) no change, and 1 (2%) a worsening score. For 1 treatment group of chronic stroke survivors, the TGS failed to identify a significant treatment response to gait training, whereas the G.A.I.T. measure was successful. The G.A.I.T. is more sensitive than the TGS for individual patients and group treatment response in identifying recovery of volitional control of gait components in response to gait training. Copyright © 2012 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Gait Deviations in Children with Autism Spectrum Disorders: A Review

Directory of Open Access Journals (Sweden)

Deirdre Kindregan

2015-01-01

Full Text Available In recent years, it has become clear that children with autism spectrum disorders (ASDs have difficulty with gross motor function and coordination, factors which influence gait. Knowledge of gait abnormalities may be useful for assessment and treatment planning. This paper reviews the literature assessing gait deviations in children with ASD. Five online databases were searched using keywords “gait” and “autism,” and 11 studies were found which examined gait in childhood ASD. Children with ASD tend to augment their walking stability with a reduced stride length, increased step width and therefore wider base of support, and increased time in the stance phase. Children with ASD have reduced range of motion at the ankle and knee during gait, with increased hip flexion. Decreased peak hip flexor and ankle plantar flexor moments in children with ASD may imply weakness around these joints, which is further exhibited by a reduction in ground reaction forces at toe-off in children with ASD. Children with ASD have altered gait patterns to healthy controls, widened base of support, and reduced range of motion. Several studies refer to cerebellar and basal ganglia involvement as the patterns described suggest alterations in those areas of the brain. Further research should compare children with ASD to other clinical groups to improve assessment and treatment planning.

The impact of voxel size-based inaccuracies on the mechanical behavior of thin bone structures.

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Maloul, Asmaa; Fialkov, Jeffrey; Whyne, Cari

2011-03-01

Computed tomography (CT)-based measures of skeletal geometry and material properties have been widely used to develop finite element (FE) models of bony structures. However, in the case of thin bone structures, the ability to develop FE models with accurate geometry derived from clinical CT data presents a challenge due to the thinness of the bone and the limited resolution of the imaging devices. The purpose of this study was to quantify the impact of voxel size on the thickness and intensity values of thin bone structure measurements and to assess the effect of voxel size on strains through FE modeling. Cortical bone thickness and material properties in five thin bone specimens were quantified at voxel sizes ranging from 16.4 to 488 μm. The measurements derived from large voxel size scans showed large increases in cortical thickness (61.9-252.2%) and large decreases in scan intensity (12.9-49.5%). Maximum principal strains from FE models generated using scans at 488 μm were decreased as compared to strains generated at 16.4 μm voxel size (8.6-64.2%). A higher level of significance was found in comparing intensity (p = 0.0001) vs. thickness (p = 0.005) to strain measurements. These findings have implications in developing methods to generate accurate FE models to predict the biomechanical behavior of thin bone structures.

Discrepancy between perceived pain and cortical processing: A voxel-based morphometry and contact heat evoked potential study.

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Kramer, J L K; Jutzeler, C R; Haefeli, J; Curt, A; Freund, P

2016-01-01

The purpose of this study was to determine if local gray and white matter volume variations between subjects could account for variability in responses to CHEP stimulation. Structural magnetic resonance imaging was used to perform voxel-based morphometry (VBM) of gray and white matter in 30 neurologically healthy subjects. Contact heat stimulation was performed on the dorsum of the right hand at the base of the thumb. Evoked potentials were acquired from a vertex-recording electrode referenced to linked ears. Controlling for age, total intracranial volume, and skull/scalp thickness, CHEP amplitude and pain rating were not significantly correlated between subjects. A VBM region of interest approach demonstrated a significant interaction between pain rating and N2 amplitude in the right insular cortex (ppain rating. This finding suggests that the discrepancy between pain ratings and the amplitude of evoked potentials is not solely related to measurement artifact, but rather attributable, in part, to anatomical differences between subjects. Crown Copyright © 2015. Published by Elsevier Ireland Ltd. All rights reserved.

A method to standardize gait and balance variables for gait velocity.

NARCIS (Netherlands)

Iersel, M.B. van; Olde Rikkert, M.G.M.; Borm, G.F.

2007-01-01

Many gait and balance variables depend on gait velocity, which seriously hinders the interpretation of gait and balance data derived from walks at different velocities. However, as far as we know there is no widely accepted method to correct for effects of gait velocity on other gait and balance

Balance and gait improved in patients with MS after physiotherapy based on the Bobath concept.

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Smedal, Tori; Lygren, Hildegunn; Myhr, Kjell-Morten; Moe-Nilssen, Rolf; Gjelsvik, Bente; Gjelsvik, Olav; Strand, Liv Inger; Inger, Liv

2006-06-01

Patients with multiple sclerosis (MS) tend to have movement difficulties, and the effect of physiotherapy for this group of patients has been subjected to limited systematic research. In the present study physiotherapy based on the Bobath concept, applied to MS patients with balance and gait problems, was evaluated. The ability of different functional tests to demonstrate change was evaluated. A single-subject experimental study design with ABAA phases was used, and two patients with relapsing-remitting MS in stable phase were treated. Tests were performed 12 times, three at each phase: A (at baseline); B (during treatment); A (immediately after treatment); and A (after two months). The key feature of treatment was facilitation of postural activity and selective control of movement. Several performance and self report measures and interviews were used. After intervention, improved balance was shown by the Berg Balance Scale (BBS) in both patients, and improved quality of gait was indicated by the Rivermead Visual Gait Assessment (RVGA). The patients also reported improved balance and gait function in the interviews and scored their condition as 'much improved'. Gait parameters, recorded by an electronic walkway, changed, but differently in the two patients. Among the physical performance tests the BBS and the RVGA demonstrated the highest change, while no or minimal change was demonstrated by the Rivermead Mobility Index (RMI) and Ratings of Perceived Exertion (RPE). The findings indicate that balance and gait can be improved after physiotherapy based on the Bobath concept, but this should be further evaluated in larger controlled trials of patients with MS.

Feature selection gait-based gender classification under different circumstances

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Sabir, Azhin; Al-Jawad, Naseer; Jassim, Sabah

2014-05-01

This paper proposes a gender classification based on human gait features and investigates the problem of two variations: clothing (wearing coats) and carrying bag condition as addition to the normal gait sequence. The feature vectors in the proposed system are constructed after applying wavelet transform. Three different sets of feature are proposed in this method. First, Spatio-temporal distance that is dealing with the distance of different parts of the human body (like feet, knees, hand, Human Height and shoulder) during one gait cycle. The second and third feature sets are constructed from approximation and non-approximation coefficient of human body respectively. To extract these two sets of feature we divided the human body into two parts, upper and lower body part, based on the golden ratio proportion. In this paper, we have adopted a statistical method for constructing the feature vector from the above sets. The dimension of the constructed feature vector is reduced based on the Fisher score as a feature selection method to optimize their discriminating significance. Finally k-Nearest Neighbor is applied as a classification method. Experimental results demonstrate that our approach is providing more realistic scenario and relatively better performance compared with the existing approaches.

To pace or not to pace: a pilot study of four- and five-gaited Icelandic horses homozygous for the DMRT3 'Gait Keeper' mutation.

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Jäderkvist Fegraeus, K; Hirschberg, I; Árnason, T; Andersson, L; Velie, B D; Andersson, L S; Lindgren, G

2017-12-01

The Icelandic horse is a breed known mainly for its ability to perform the ambling four-beat gait 'tölt' and the lateral two-beat gait pace. The natural ability of the breed to perform these alternative gaits is highly desired by breeders. Therefore, the discovery that a nonsense mutation (C>A) in the DMRT3 gene was the main genetic factor for horses' ability to perform gaits in addition to walk, trot and canter was of great interest. Although several studies have demonstrated that homozygosity for the DMRT3 mutation is important for the ability to pace, only about 70% of the homozygous mutant (AA) Icelandic horses are reported to pace. The aim of the study was to genetically compare four- and five-gaited (i.e. horses with and without the ability to pace) AA Icelandic horses by performing a genome-wide association (GWA) analysis. All horses (n = 55) were genotyped on the 670K Axiom Equine Genotyping Array, and a GWA analysis was performed using the genabel package in r. No SNP demonstrated genome-wide significance, implying that the ability to pace goes beyond the presence of a single gene variant. Despite its limitations, the current study provides additional information regarding the genetic complexity of pacing ability in horses. However, to fully understand the genetic differences between four- and five-gaited AA horses, additional studies with larger sample materials and consistent phenotyping are needed. © 2017 Stichting International Foundation for Animal Genetics.

Voxel-by-voxel analysis of brain SPECT perfusion in Fibromyalgia

International Nuclear Information System (INIS)

Guedj, Eric; Taieb, David; Cammilleri, Serge; Lussato, David; Laforte, Catherine de; Niboyet, Jean; Mundler, Olivier

2007-01-01

We evaluated brain perfusion SPECT at rest, without noxious stiumuli, in a homogeneous group of hyperalgesic FM patients. We performed a voxel-based analysis in comparison to a control group, matched for age and gender. Under such conditions, we made the assumption that significant cerebral perfusion abnormalities could be demonstrated, evidencing altered cerebral processing associated with spontaneous pain in FM patients. The secondary objective was to study the reversibility and the prognostic value of such possible perfusion abnormalities under specific treatment. Eighteen hyperalgesic FM women (mean age 48 yr; range 25-63 yr; ACR criteria) and 10 healthy women matched for age were enrolled in the study. A voxel-by-voxel group analysis was performed using SPM2 (p<0.05, corrected for multiple comparisons). All brain SPECT were performed before any change was made in therapy in the pain care unit. A second SPECT was performed a month later after specific treatment by Ketamine. Compared to control subjects, we observed individual brain SPECT abnormalities in FM patients, confirmed by SPM2 analysis with hyperperfusion of the somatosensory cortex and hypoperfusion of the frontal, cingulate, medial temporal and cerebellar cortices. We also found that a medial frontal and anterior cingulate hypoperfusions were highly predictive (PPV=83%; NPV=91%) of non-response on Ketamine, and that only responders showed significant modification of brain perfusion, after treatment. In the present study performed without noxious stimuli in hyperalgesic FM patients, we found significant hyperperfusion in regions of the brain known to be involved in sensory dimension of pain processing and significant hypoperfusion in areas assumed to be associated with the affective dimension. As current pharmacological and non-pharmacological therapies act differently on both components of pain, we hypothesize that SPECT could be a valuable and readily available tool to guide individual therapeutic

Voxel-by-voxel analysis of brain SPECT perfusion in Fibromyalgia

Energy Technology Data Exchange (ETDEWEB)

Guedj, Eric [Service Central de Biophysique et de Medecine Nucleaire, AP-HM Timone, Marseille (France)]. E-mail: eric.guedj@ap-hm.fr; Taieb, David [Service Central de Biophysique et de Medecine Nucleaire, AP-HM Timone, Marseille (France); Cammilleri, Serge [Service Central de Biophysique et de Medecine Nucleaire, AP-HM Timone, Marseille (France); Lussato, David [Service Central de Biophysique et de Medecine Nucleaire, AP-HM Timone, Marseille (France); Laforte, Catherine de [Service Central de Biophysique et de Medecine Nucleaire, AP-HM Timone, Marseille (France); Niboyet, Jean [Unite d' Etude et de Traitement de la Douleur, Clinique La Phoceanne, Marseille (France); Mundler, Olivier [Service Central de Biophysique et de Medecine Nucleaire, AP-HM Timone, Marseille (France)

2007-02-01

We evaluated brain perfusion SPECT at rest, without noxious stiumuli, in a homogeneous group of hyperalgesic FM patients. We performed a voxel-based analysis in comparison to a control group, matched for age and gender. Under such conditions, we made the assumption that significant cerebral perfusion abnormalities could be demonstrated, evidencing altered cerebral processing associated with spontaneous pain in FM patients. The secondary objective was to study the reversibility and the prognostic value of such possible perfusion abnormalities under specific treatment. Eighteen hyperalgesic FM women (mean age 48 yr; range 25-63 yr; ACR criteria) and 10 healthy women matched for age were enrolled in the study. A voxel-by-voxel group analysis was performed using SPM2 (p<0.05, corrected for multiple comparisons). All brain SPECT were performed before any change was made in therapy in the pain care unit. A second SPECT was performed a month later after specific treatment by Ketamine. Compared to control subjects, we observed individual brain SPECT abnormalities in FM patients, confirmed by SPM2 analysis with hyperperfusion of the somatosensory cortex and hypoperfusion of the frontal, cingulate, medial temporal and cerebellar cortices. We also found that a medial frontal and anterior cingulate hypoperfusions were highly predictive (PPV=83%; NPV=91%) of non-response on Ketamine, and that only responders showed significant modification of brain perfusion, after treatment. In the present study performed without noxious stimuli in hyperalgesic FM patients, we found significant hyperperfusion in regions of the brain known to be involved in sensory dimension of pain processing and significant hypoperfusion in areas assumed to be associated with the affective dimension. As current pharmacological and non-pharmacological therapies act differently on both components of pain, we hypothesize that SPECT could be a valuable and readily available tool to guide individual therapeutic

A voxel-based morphometry study of regional gray and white matter correlate of self-disclosure.

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Wang, ShanShan; Wei, DongTao; Li, WenFu; Li, HaiJiang; Wang, KangCheng; Xue, Song; Zhang, Qinglin; Qiu, Jiang

2014-01-01

Self-disclosure is an important performance in human social communication. Generally, an individual is likely to have a good physical and mental health if he is prone to self-disclosure under stressful life events. However, as for now, little is known about the neural structure associated with self-disclosure. Therefore, in this study, we used voxel-based morphometry to explore regional gray matter volume (rGMV) and white matter volume (rWMV) associated with self-disclosure measured by the Jourard Self-disclosure Questionnaire in a large sample of college students. Results showed that individual self-disclosure was significantly and positively associated with rGMV of the left postcentral gyrus, which might be related to strengthen individual's ability of body feeling; while self-disclosure was significantly and negatively associated with rGMV of the right orbitofrontal cortex (OFC), which might be involved in increased positive emotion experience seeking (intrinsically rewarding). In addition, individual self-disclosure was also associated with smaller rWMV in the right inferior parietal lobule (IPL). These findings suggested a biological basis for individual self-disclosure, distributed across different gray and white matter areas of the brain.

Gait outcome following outpatient physiotherapy based on the Bobath concept in people post stroke.

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Lennon, Sheila; Ashburn, Ann; Baxter, David

The purpose of this study was to characterize the gait cycle of patients with hemiplegia before and after a period of outpatient physiotherapy based on the Bobath concept. Nine patients, at least 6 weeks post stroke and recently discharged from a stroke unit, were measured before and after a period of outpatient physiotherapy (mean duration = 17.4 weeks). Therapy was documented using a treatment checklist for each patient. The primary outcome measures were a number of gait variables related to the therapists' treatment hypothesis, recorded during the gait cycle using the CODA motion analysis system. Other secondary outcome measures were the Motor Assessment Scale, Modified Ashworth Scale, subtests of the Sodring Motor Evaluation Scale, the Step test, a 10-m walk test, the Barthel Index and the London Handicap Score. Recovery of more normal gait patterns in the gait cycle (using motion analysis) did not occur. Significant changes in temporal parameters (loading response, single support time) for both legs, in one kinematic (dorsiflexion during stance) and one kinetic variable on the unaffected side (hip flexor moment), and most of the clinical measures of impairment, activity and participation (with the exception of the Modified Ashworth Scale and the 10-m walk) were noted. Study findings did not support the hypothesis that the Bobath approach restored more normal movement patterns to the gait cycle. Further research is required to investigate the treatment techniques that are effective at improving walking ability in people after stroke.

Effects of yoga on balance and gait properties in women with musculoskeletal problems: a pilot study.

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Ulger, Ozlem; Yağlı, Naciye Vardar

2011-02-01

The purpose of the present study is to investigate the effects of yoga on balance and gait properties in women with musculoskeletal problems. Twenty-seven women (30-45 years old) with musculoskeletal problems, such as osteoarthritis and low-back pain, were included in the present study. The patients participated in 8 sessions (twice weekly for 4 weeks) of a yoga program which included asanas, stretching exercises, and breathing techniques. Patients' static balance measurements and gait parameters were determined before and after the study using a stabilometer and a gait trainer, respectively. Post-study values of patients' gait parameters were found to be statistically higher than their pre-study values (p gait parameters of women with gait and balance disturbances that are caused by musculoskeletal problems. It is feasible to conclude that asanas and stretching exercises included in the yoga program brought about such a positive effect, and therefore it is possible to use yoga programs to solve problems caused by musculoskeletal disorders. Copyright © 2010 Elsevier Ltd. All rights reserved.

A Voxel-Based Method for Automated Identification and Morphological Parameters Estimation of Individual Street Trees from Mobile Laser Scanning Data

Directory of Open Access Journals (Sweden)

Hongxing Liu

2013-01-01

Full Text Available As an important component of urban vegetation, street trees play an important role in maintenance of environmental quality, aesthetic beauty of urban landscape, and social service for inhabitants. Acquiring accurate and up-to-date inventory information for street trees is required for urban horticultural planning, and municipal urban forest management. This paper presents a new Voxel-based Marked Neighborhood Searching (VMNS method for efficiently identifying street trees and deriving their morphological parameters from Mobile Laser Scanning (MLS point cloud data. The VMNS method consists of six technical components: voxelization, calculating values of voxels, searching and marking neighborhoods, extracting potential trees, deriving morphological parameters, and eliminating pole-like objects other than trees. The method is validated and evaluated through two case studies. The evaluation results show that the completeness and correctness of our method for street tree detection are over 98%. The derived morphological parameters, including tree height, crown diameter, diameter at breast height (DBH, and crown base height (CBH, are in a good agreement with the field measurements. Our method provides an effective tool for extracting various morphological parameters for individual street trees from MLS point cloud data.

Diffusion tensor imaging of nigral degeneration in Parkinson's disease: A region-of-interest and voxel-based study at 3 T and systematic review with meta-analysis☆

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Schwarz, Stefan T.; Abaei, Maryam; Gontu, Vamsi; Morgan, Paul S.; Bajaj, Nin; Auer, Dorothee P.

2013-01-01

There is increasing interest in developing a reliable, affordable and accessible disease biomarker of Parkinson's disease (PD) to facilitate disease modifying PD-trials. Imaging biomarkers using magnetic resonance imaging (MRI) and diffusion tensor imaging (DTI) can describe parameters such as fractional anisotropy (FA), mean diffusivity (MD) or apparent diffusion coefficient (ADC). These parameters, when measured in the substantia nigra (SN), have not only shown promising but also varying and controversial results. To clarify the potential diagnostic value of nigral DTI in PD and its dependency on selection of region-of-interest, we undertook a high resolution DTI study at 3 T. 59 subjects (32 PD patients, 27 age and sex matched healthy controls) were analysed using manual outlining of SN and substructures, and voxel-based analysis (VBA). We also performed a systematic literature review and meta-analysis to estimate the effect size (DES) of disease related nigral DTI changes. We found a regional increase in nigral mean diffusivity in PD (mean ± SD, PD 0.80 ± 0.10 vs. controls 0.73 ± 0.06 · 10− 3 mm2/s, p = 0.002), but no difference using a voxel based approach. No significant disease effect was seen using meta-analysis of nigral MD changes (10 studies, DES = + 0.26, p = 0.17, I2 = 30%). None of the nigral regional or voxel based analyses of this study showed altered fractional anisotropy. Meta-analysis of 11 studies on nigral FA changes revealed a significant PD induced FA decrease. There was, however, a very large variation in results (I2 = 86%) comparing all studies. After exclusion of five studies with unusual high values of nigral FA in the control group, an acceptable heterogeneity was reached, but there was non-significant disease effect (DES = − 0.5, p = 0.22, I2 = 28%). The small PD related nigral MD changes in conjunction with the negative findings on VBA and meta-analysis limit the usefulness of nigral MD measures as

White matter and schizophrenia: A meta-analysis of voxel-based morphometry and diffusion tensor imaging studies.

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Vitolo, Enrico; Tatu, Mona Karina; Pignolo, Claudia; Cauda, Franco; Costa, Tommaso; Ando', Agata; Zennaro, Alessandro

2017-12-30

Voxel-based morphometry (VBM) and diffusion tensor imaging (DTI) are the most implemented methodologies to detect alterations of both gray and white matter (WM). However, the role of WM in mental disorders is still not well defined. We aimed at clarifying the role of WM disruption in schizophrenia and at identifying the most frequently involved brain networks. A systematic literature search was conducted to identify VBM and DTI studies focusing on WM alterations in patients with schizophrenia compared to control subjects. We selected studies reporting the coordinates of WM reductions and we performed the anatomical likelihood estimation (ALE). Moreover, we labeled the WM bundles with an anatomical atlas and compared VBM and DTI ALE-scores of each significant WM tract. A total of 59 studies were eligible for the meta-analysis. WM alterations were reported in 31 and 34 foci with VBM and DTI methods, respectively. The most occurred WM bundles in both VBM and DTI studies and largely involved in schizophrenia were long projection fibers, callosal and commissural fibers, part of motor descending fibers, and fronto-temporal-limbic pathways. The meta-analysis showed a widespread WM disruption in schizophrenia involving specific cerebral circuits instead of well-defined regions. Copyright © 2017 Elsevier B.V. All rights reserved.

Voxel-based analysis of whole-brain effects of age and gender on dopamine transporter SPECT imaging in healthy subjects

International Nuclear Information System (INIS)

Eusebio, Alexandre; Azulay, Jean-Philippe; Ceccaldi, Mathieu; Girard, Nadine; Mundler, Olivier; Guedj, Eric

2012-01-01

Several studies have shown age- and gender-related differences in striatal dopamine transporter (DaT) binding. These studies were based on a striatal region on interest approach that may have underestimated these effects and could not evaluate extrastriatal regions. Our aim was to determine the effects at the voxel level of age and gender on whole-brain DaT distribution using [ 123 I]FP-CIT SPECT in healthy subjects. We performed a whole-brain [ 123 I]FP-CIT SPECT voxel-based analysis using SPM8 and a standardized normalization template (p < 0.05, corrected using the false discovery rate method) in 51 healthy subjects aged from 21 to 79 years. We found an age-related DaT binding decrease in the striatum, anterior cingulate/medial frontal cortices and insulo-opercular cortices. Also DaT binding ratios were higher in women than men in the striatum and opercular cortices. This study showed both striatal and extrastriatal age-related and gender-related differences in DaT binding in healthy subjects using a whole-brain voxel-based non-a priori approach. These differences highlight the need for careful age and gender matching in DaT analyses of neuropsychiatric disorders. (orig.)

Voxel-based analysis of whole-brain effects of age and gender on dopamine transporter SPECT imaging in healthy subjects

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Eusebio, Alexandre; Azulay, Jean-Philippe [APHM, Hopital de la Timone, Service de Neurologie et Pathologie du Mouvement, Marseille (France); CNRS, Aix-Marseille Univ, Institut de Neurosciences de la Timone, Marseille (France); Ceccaldi, Mathieu [APHM, Hopital de la Timone, Service de Neurologie et de Neuropsychologie, Marseille (France); Aix-Marseille Univ, UMR Inserm 1106, Institut de Neurosciences des Systemes, Marseille (France); Girard, Nadine [APHM, Hopital de la Timone, Service de Neuroradiologie diagnostique et interventionnelle, Marseille (France); Mundler, Olivier [APHM, Hopital de la Timone, Service Central de Biophysique et Medecine Nucleaire, Marseille (France); Aix-Marseille Univ, CERIMED, Marseille (France); Guedj, Eric [CNRS, Aix-Marseille Univ, Institut de Neurosciences de la Timone, Marseille (France); APHM, Hopital de la Timone, Service Central de Biophysique et Medecine Nucleaire, Marseille (France); Aix-Marseille Univ, CERIMED, Marseille (France)

2012-11-15

Several studies have shown age- and gender-related differences in striatal dopamine transporter (DaT) binding. These studies were based on a striatal region on interest approach that may have underestimated these effects and could not evaluate extrastriatal regions. Our aim was to determine the effects at the voxel level of age and gender on whole-brain DaT distribution using [{sup 123}I]FP-CIT SPECT in healthy subjects. We performed a whole-brain [{sup 123}I]FP-CIT SPECT voxel-based analysis using SPM8 and a standardized normalization template (p < 0.05, corrected using the false discovery rate method) in 51 healthy subjects aged from 21 to 79 years. We found an age-related DaT binding decrease in the striatum, anterior cingulate/medial frontal cortices and insulo-opercular cortices. Also DaT binding ratios were higher in women than men in the striatum and opercular cortices. This study showed both striatal and extrastriatal age-related and gender-related differences in DaT binding in healthy subjects using a whole-brain voxel-based non-a priori approach. These differences highlight the need for careful age and gender matching in DaT analyses of neuropsychiatric disorders. (orig.)

Increased gray matter density in the parietal cortex of mathematicians: a voxel-based morphometry study.

Science.gov (United States)

Aydin, K; Ucar, A; Oguz, K K; Okur, O O; Agayev, A; Unal, Z; Yilmaz, S; Ozturk, C

2007-01-01

The training to acquire or practicing to perform a skill, which may lead to structural changes in the brain, is called experience-dependent structural plasticity. The main purpose of this cross-sectional study was to investigate the presence of experience-dependent structural plasticity in mathematicians' brains, which may develop after long-term practice of mathematic thinking. Twenty-six volunteer mathematicians, who have been working as academicians, were enrolled in the study. We applied an optimized method of voxel-based morphometry in the mathematicians and the age- and sex-matched control subjects. We assessed the gray and white matter density differences in mathematicians and the control subjects. Moreover, the correlation between the cortical density and the time spent as an academician was investigated. We found that cortical gray matter density in the left inferior frontal and bilateral inferior parietal lobules of the mathematicians were significantly increased compared with the control subjects. Furthermore, increase in gray matter density in the right inferior parietal lobule of the mathematicians was strongly correlated with the time spent as an academician (r = 0.84; P mathematicians' brains revealed increased gray matter density in the cortical regions related to mathematic thinking. The correlation between cortical density increase and the time spent as an academician suggests experience-dependent structural plasticity in mathematicians' brains.

Regional patterns of grey matter atrophy and magnetisation transfer ratio abnormalities in multiple sclerosis clinical subgroups: a voxel-based analysis study.

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Mallik, Shahrukh; Muhlert, Nils; Samson, Rebecca S; Sethi, Varun; Wheeler-Kingshott, Claudia A M; Miller, David H; Chard, Declan T

2015-04-01

In multiple sclerosis (MS), demyelination and neuro-axonal loss occur in the brain grey matter (GM). We used magnetic resonance imaging (MRI) measures of GM magnetisation transfer ratio (MTR) and volume to assess the regional localisation of reduced MTR (reflecting demyelination) and atrophy (reflecting neuro-axonal loss) in relapsing-remitting MS (RRMS), secondary progressive MS (SPMS) and primary progressive MS (PPMS). A total of 98 people with MS (51 RRMS, 28 SPMS, 19 PPMS) and 29 controls had T1-weighted volumetric and magnetisation transfer scans. SPM8 was used to undertake voxel-based analysis (VBA) of GM tissue volumes and MTR. MS subgroups were compared with controls, adjusting for age and gender. A voxel-by-voxel basis correlation analysis between MTR and volume within each subject group was performed, using biological parametric mapping. MTR reduction was more extensive than atrophy. RRMS and SPMS patients showed proportionately more atrophy in the deep GM. SPMS and PPMS patients showed proportionately greater cortical MTR reduction. RRMS patients demonstrated the most correlation of MTR reduction and atrophy in deep GM. In SPMS and PPMS patients, there was less extensive correlation. These results suggest that in the deep GM of RRMS patients, demyelination and neuro-axonal loss may be linked, while in SPMS and PPMS patients, neuro-axonal loss and demyelination may occur mostly independently. © The Author(s), 2014.

Grey matter volume differences associated with gender in children with attention-deficit/hyperactivity disorder: A voxel-based morphometry study.

Science.gov (United States)

Villemonteix, Thomas; De Brito, Stéphane A; Slama, Hichem; Kavec, Martin; Balériaux, Danielle; Metens, Thierry; Baijot, Simon; Mary, Alison; Peigneux, Philippe; Massat, Isabelle

2015-08-01

Female participants have been underrepresented in previous structural magnetic resonance imaging reports on attention-deficit/hyperactivity disorder (ADHD). In this study, we used optimized voxel-based morphometry to examine grey matter volumes in a sample of 33 never-medicated children with combined-type ADHD and 27 typically developing (TD) children. We found a gender-by-diagnosis interaction effect in the ventral anterior cingulate cortex (ACC), whereby boys with ADHD exhibited reduced volumes compared with TD boys, while girls with ADHD showed increased volumes when compared with TD girls. Considering the key role played by the ventral ACC in emotional regulation, we discuss the potential contribution of these alterations to gender-specific symptoms' profiles in ADHD. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

Neuroanatomical Alterations in Patients with Early Stage of Unilateral Pulsatile Tinnitus: A Voxel-Based Morphometry Study

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Yawen Liu

2018-01-01

Full Text Available During the past several years, the rapid development of neuroimaging techniques has contributed greatly in the noninvasive imaging studies of tinnitus. The aim of the present study was to explore the brain anatomical alterations in patients with right-sided unilateral pulsatile tinnitus (PT in the early stage of PT symptom using voxel-based morphometry (VBM analysis. Twenty-four patients with right-sided pulsatile tinnitus and 24 age- and gender-matched normal controls were recruited to this study. Structural image data preprocessing was performed using VBM8 toolbox. Tinnitus Handicap Inventory (THI score was acquired in the tinnitus group to assess the severity of tinnitus and tinnitus-related distress. Two-sample t-test and Pearson’s correlation analysis were used in statistical analysis. Patients with unilateral pulsatile tinnitus had significantly increased gray matter (GM volume in bilateral superior temporal gyrus compared with the normal controls. However, the left cerebellum posterior lobe, left frontal superior orbital lobe (gyrus rectus, right middle occipital gyrus (MOG, and bilateral putamen showed significantly decreased brain volumes. This was the first study which demonstrated the features of neuroanatomical changes in patients with unilateral PT during their early stages of the symptom.

Balance and gait in older electroconvulsive therapy recipients: a pilot study

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Plakiotis C

2013-06-01

Full Text Available Chris Plakiotis,1,2 Fay Barson,2 Bharathi Vengadasalam,3 Terry P Haines,4 Daniel W O'Connor1,2 1School of Psychology and Psychiatry, Monash University, Melbourne, VIC, Australia; 2MonashHealth, Melbourne, VIC, Australia; 3Universiti Putra Malaysia, Serdang, Selangor, Malaysia; 4Allied Health Research Unit, Monash University and MonashHealth, Melbourne, VIC, Australia Background: Electroconvulsive therapy (ECT is commonly used to treat depression in older adults. Despite its efficacy in this regard, an associated increase in the risk of falls in this population is a downside of treatment. ECT research has focused on the incidence of falls, but its effect on balance and gait – intrinsic factors in instability and falls – has not been studied. Our aim was to examine changes in balance and gait among older adults before and after a single ECT session and explore the effect of patient-related and treatment factors on any changes found. Methods: Participants were 21 older adults requiring ECT for depression in public psychiatric services. Patients with clinically overt mobility problems (impairing test participation or increasing the risk of falls were excluded. Balance and gait testing 1 hour pre-ECT and 1, 2 and 3 hours post-ECT included: (1 steady standing test; (2 perturbation of standing balance by self-initiated movements; (3 perturbation of standing balance by an external perturbation; and (4 timed up and go test. Results: No deterioration in test performance was found, using one-way repeated measures analysis of variance. Conclusion: Balance and gait did not deteriorate immediately after ECT. Exclusion of participants with clinically overt mobility problems and falls being better attributable to factors unrelated to balance and gait (such as post-ECT confusion may account for our findings. This research does not repudiate the occurrence of ECT-related falls but calls into question the utility of introducing routine balance and gait

Anatomy of the Episodic Buffer: A Voxel-Based Morphometry Study in Patients with Dementia

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M. Berlingeri

2008-01-01

Full Text Available In 2000 Baddeley proposed the existence of a new component of working memory, the episodic buffer, which should contribute to the on-line maintenance of integrated memory traces. The author assumed that this component should be critical for immediate recall of a short story that exceeds the capacity of the phonological store. Accordingly, patients with Alzheimer’s dementia (AD should suffer of a deficit of the episodic buffer when immediate recall of a short story is impossible. On the other hand, the episodic buffer should be somewhat preserved in such patients when some IR can occur (Baddeley and Wilson, 2002. We adopted this logic for a voxel-based morphometry study. We compared the distribution of grey-matter density of two such groups of AD patients with a group of age-matched controls. We found that both AD groups had a significant atrophy of the left mid-hippocampus; on the other hand, the anterior part of the hippocampus was significantly more atrophic in patients who were also impaired on the immediate prose recall task. Six out of ten patients with no immediate recall were spared at “central executive” tasks. Taken together our findings suggest that the left anterior hippocampus contributes to the episodic buffer of the revised working memory model. We also suggest that the episodic buffer is somewhat independent from the central executive component of working memory.

Relationship between personality and gray matter volume in healthy young adults: a voxel-based morphometric study.

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Fengmei Lu

Full Text Available This study aims to investigate the neurostructural foundations of the human personality in young adults. High-resolution structural T1-weighted MR images of 71 healthy young individuals were processed using voxel-based morphometric (VBM approach. Multiple regression analyses were performed to identify the associations between personality traits and gray matter volume (GMV. The Eysenck Personality Questionnaire-Revised, Short Scale for Chinese was chosen to assess the personality traits. This scale includes four dimensions, namely, extraversion, neuroticism, psychoticism, and lie. Particularly, we studied on two dimensions (extraversion and neuroticism of Eysenck's personality. Our results showed that extraversion was negatively correlated with GMV of the bilateral amygdala, the bilateral parahippocampal gyrus, the right middle temporal gyrus, and the left superior frontal gyrus, all of which are involved in emotional and social cognitive processes. These results might suggest an association between extraversion and affective processing. In addition, a positive correlation was detected between neuroticism and GMV of the right cerebellum, a key brain region for negative affect coordination. Meanwhile, a negative association was revealed between GMV of the left superior frontal gyrus and neuroticism. These results may prove that neuroticism is related to several brain regions involved in regulating negative emotions. Based on those findings, we concluded that brain regions involved in social cognition and affective process accounted for modulation and shaping of personality traits among young individuals. Results of this study may serve as a basis for elucidating the anatomical factors of personality.

Alexithymia is related to differences in gray matter volume: a voxel-based morphometry study.

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Ihme, Klas; Dannlowski, Udo; Lichev, Vladimir; Stuhrmann, Anja; Grotegerd, Dominik; Rosenberg, Nicole; Kugel, Harald; Heindel, Walter; Arolt, Volker; Kersting, Anette; Suslow, Thomas

2013-01-23

Alexithymia has been characterized as the inability to identify and describe feelings. Functional imaging studies have revealed that alexithymia is linked to reactivity changes in emotion- and face-processing-relevant brain areas. In this respect, anterior cingulate cortex (ACC), amygdala, anterior insula and fusiform gyrus (FFG) have been consistently reported. However, it remains to be clarified whether alexithymia is also associated with structural differences. Voxel-based morphometry on T1-weighted magnetic resonance images was used to investigate gray matter volume in 17 high alexithymics (HA) and 17 gender-matched low alexithymics (LA), which were selected from a sample of 161 healthy volunteers on basis of the 20-item Toronto Alexithymia Scale. Data were analyzed as statistic parametric maps for the comparisons LA>HA and HA>LA in a priori determined regions of interests (ROIs), i.e., ACC, amygdala, anterior insula and FFG. Moreover, an exploratory whole brain analysis was accomplished. For the contrast LA>HA, significant clusters were detected in the ACC, left amygdala and left anterior insula. Additionally, the whole brain analysis revealed volume differences in the left middle temporal gyrus. No significant differences were found for the comparison HA>LA. Our findings suggest that high compared to low alexithymics show less gray matter volume in several emotion-relevant brain areas. These structural differences might contribute to the functional alterations found in previous imaging studies in alexithymia. Copyright © 2012 Elsevier B.V. All rights reserved.

Comparison of gray matter and metabolic reduction in mild Alzheimer's disease using FDG-PET and voxel-based morphometric MR studies

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Ishii, Kazunari; Sasaki, Hiroki; Kono, Atsushi K.; Miyamoto, Naokazu; Fukuda, Tetsuya [Hyogo Brain and Heart Center, Department of Radiology and Nuclear Medicine, Himeji, Hyogo (Japan); Mori, Etsuro [Hyogo Brain and Heart Center, Institute for Aging Brain and Cognitive Disorders, Himeji, Hyogo (Japan)

2005-08-01

The aim of this study was to investigate regional differences between morphologic and functional changes in the same patients with mild Alzheimer's disease (AD) using statistical parametric mapping (SPM) and voxel-based morphometry (VBM). Thirty patients with very mild AD (mean age 66.8 years, mean MMSE score 24.0) and 30 age- and sex-matched normal volunteers underwent both{sup 18}F-fluorodeoxyglucose (FDG) positron emission tomography (PET) and three-dimensional spoiled gradient echo (SPGR) magnetic resonance imaging (MRI). Statistical parametric mapping was used to conduct VBM analysis of the morphological data, which were compared voxel by voxel with the results of a similar analysis of the glucose metabolic data. In AD patients, VBM data indicated a significant gray matter volume density decrease in bilateral amygdala/hippocampus complex (p<0.05, corrected), while FDG-PET analysis showed significant glucose metabolic reductions in the posterior cingulate gyri and the right parietal lobule, compared with those in the normal control group. In very mild AD, morphological change occurs in the medial temporal lobes, while in contrast, metabolic changes occur in the posterior cingulate gyri and parietal lobule. (orig.)

Effects of conventional overground gait training and a gait trainer with partial body weight support on spatiotemporal gait parameters of patients after stroke.

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Park, Byoung-Sun; Kim, Mee-Young; Lee, Lim-Kyu; Yang, Seung-Min; Lee, Won-Deok; Noh, Ji-Woong; Shin, Yong-Sub; Kim, Ju-Hyun; Lee, Jeong-Uk; Kwak, Taek-Yong; Lee, Tae-Hyun; Kim, Ju-Young; Kim, Junghwan

2015-05-01

[Purpose] The purpose of this study was to confirm the effects of both conventional overground gait training (CGT) and a gait trainer with partial body weight support (GTBWS) on spatiotemporal gait parameters of patients with hemiparesis following chronic stroke. [Subjects and Methods] Thirty stroke patients were alternately assigned to one of two treatment groups, and both groups underwent CGT and GTBWS. [Results] The functional ambulation classification on the affected side improved significantly in the CGT and GTBWS groups. Walking speed also improved significantly in both groups. [Conclusion] These results suggest that the GTBWS in company with CGT may be, in part, an effective method of gait training for restoring gait ability in patients after a stroke.

Brain-volume changes in young and middle-aged smokers: a DARTEL-based voxel-based morphometry study.

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Peng, Peng; Wang, Zhenchang; Jiang, Tao; Chu, Shuilian; Wang, Shuangkun; Xiao, Dan

2017-09-01

Many studies have reported brain volume changes in smokers. However, the volume differences of grey matter (GM) and white matter (WM) in young and middle-aged male smokers with different lifetime tobacco consumption (pack-years) remain uncertain. To examine the brain volume change, especially whether more pack-years smoking would be associated with smaller gray matter and white matter volume in young and middle-aged male smokers. We used a 3T MR scanner and performed Diffeomorphic anatomical registration through exponentiated lie algebra (DARTEL)-based voxel-based morphometry on 53 long-term male smokers (30.72 ± 4.19 years) and 53 male healthy non-smokers (30.83 ± 5.18 years). We separated smokers to light and heavy smokers by pack-years and compared brain volume between different smoker groups and non-smokers. And then we did analysis of covariance (ANCOVA) between smokers and non-smokers by setting pack-years as covariates. Light and heavy smokers all displayed smaller GM and WM volume than non-smokers and more obviously in heavy smokers. The main smaller areas in light and heavy smokers were superior temporal gyrus, insula, middle occipital gyrus, posterior cingulate, precuneus in GM and posterior cingulate, thalamus and midbrain in WM, in addition, we also observed more pack-years smoking was associated with some certain smaller GM and WM volumes by ANCOVA. Young and middle-aged male smokers had many smaller brain areas than non-smokers. Some of these areas' volume had negative correlation with pack-years, while some had not. These may due to different pathophysiological role of smokings. © 2015 John Wiley & Sons Ltd.

A voxel-based mouse for internal dose calculations using Monte Carlo simulations (MCNP).

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Bitar, A; Lisbona, A; Thedrez, P; Sai Maurel, C; Le Forestier, D; Barbet, J; Bardies, M

2007-02-21

Murine models are useful for targeted radiotherapy pre-clinical experiments. These models can help to assess the potential interest of new radiopharmaceuticals. In this study, we developed a voxel-based mouse for dosimetric estimates. A female nude mouse (30 g) was frozen and cut into slices. High-resolution digital photographs were taken directly on the frozen block after each section. Images were segmented manually. Monoenergetic photon or electron sources were simulated using the MCNP4c2 Monte Carlo code for each source organ, in order to give tables of S-factors (in Gy Bq-1 s-1) for all target organs. Results obtained from monoenergetic particles were then used to generate S-factors for several radionuclides of potential interest in targeted radiotherapy. Thirteen source and 25 target regions were considered in this study. For each source region, 16 photon and 16 electron energies were simulated. Absorbed fractions, specific absorbed fractions and S-factors were calculated for 16 radionuclides of interest for targeted radiotherapy. The results obtained generally agree well with data published previously. For electron energies ranging from 0.1 to 2.5 MeV, the self-absorbed fraction varies from 0.98 to 0.376 for the liver, and from 0.89 to 0.04 for the thyroid. Electrons cannot be considered as 'non-penetrating' radiation for energies above 0.5 MeV for mouse organs. This observation can be generalized to radionuclides: for example, the beta self-absorbed fraction for the thyroid was 0.616 for I-131; absorbed fractions for Y-90 for left kidney-to-left kidney and for left kidney-to-spleen were 0.486 and 0.058, respectively. Our voxel-based mouse allowed us to generate a dosimetric database for use in preclinical targeted radiotherapy experiments.

The overlapping brain region accounting for the relationship between procrastination and impulsivity: A voxel-based morphometry study.

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Liu, Peiwei; Feng, Tingyong

2017-09-30

Procrastination is a prevalent problematic behavior that brings serious consequences, such as lower levels of health, wealth, and well-being. Previous research has verified that impulsivity is one of the traits most strongly correlated with procrastination. However, little is known about why there is a tight behavioral relationship between them. To address this question, we used voxel-based morphometry (VBM) to explore the common neural substrates between procrastination and impulsivity. In line with previous findings, the behavioral results showed a strong behavioral correlation between procrastination and impulsivity. Neuroimaging results showed impulsivity and procrastination shared the common neurobiological underpinnings in the dorsolateral prefrontal cortex (DLPFC) based on the data from 85 participants (sample 1). Furthermore, the mediation analysis revealed that impulsivity mediated the impact of gray matter (GM) volumes of this overlapping region in the DLPFC on procrastination on another independent 84 participants' data (sample 2). In conclusion, the overlapping brain region in the DLPFC would be responsible for the close relationship between procrastination and impulsivity. As a whole, the present study extends our knowledge on procrastination, and provides a novel perspective to explain the tight impulsivity - procrastination relationship. Copyright © 2017 IBRO. Published by Elsevier Ltd. All rights reserved.

Progressive and widespread brain damage in ALS: MRI voxel-based morphometry and diffusion tensor imaging study.

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Senda, Joe; Kato, Shigenori; Kaga, Tomotsugu; Ito, Mizuki; Atsuta, Naoki; Nakamura, Tomohiko; Watanabe, Hirohisa; Tanaka, Fumiaki; Naganawa, Shinji; Sobue, Gen

2011-01-01

We investigated 17 patients with sporadic amyotrophic lateral sclerosis (ALS) using voxel-based morphometry (VBM) and voxel-based analysis of diffusion tensor images (DTI) at baseline and after a six-month follow-up. Compared with 17 healthy controls, ALS patients at baseline showed only minimal white matter volume decreases in the inferior frontal gyrus but marked decreases in the gray matter of several regions, especially in the bilateral paracentral lobule of the premotor cortex. DTI revealed reduced fractional anisotropy in the bilateral corticospinal tracts, insula, ventrolateral premotor cortex, and parietal cortex. Increased mean diffusivity was noted bilaterally in the motor cortex, ventrolateral premotor cortex, insula, hippocampal formation, and temporal gyrus. At the six-month follow-up, ALS patients showed widespread volume decreases in gray matter, and DTI abnormalities extended mainly into the bilateral frontal lobes, while volume changes in the white matter remained minimal but more distinct. Our combined VBM and DTI techniques revealed extra-corticospinal tract neuronal degeneration mainly in the frontotemporal lobe of ALS patients. In particular, follow-up examinations in these patients showed that whole-brain DTI changes occurred predominantly in the regions of brain atrophy. These objective analyses can be used to assess the disease condition of the ALS brain.

Balance and Gait Impairment: Sensor-Based Assessment for Patients With Peripheral Neuropathy.

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Campbell, Grace; Skubic, Marjorie A

2018-06-01

Individuals with peripheral neuropathy (PN) frequently experience balance and gait impairments that can lead to poor physical function, falls, and injury. Nurses are aware that patients with cancer experience balance and gait impairments but are unsure of optimal assessment and management strategies. This article reviews options for balance and gait assessment for patients diagnosed with cancer experiencing PN, describes advantages and limitations of the various options, and highlights innovative, clinically feasible technologies to improve clinical assessment and management. The literature was reviewed to identify and assess the gold standard quantitative measures for assessing balance and gait. Gold standard quantitative measures are burdensome for patients and not often used in clinical practice. Sensor-based technologies improve balance and gait assessment options by calculating precise impairment measures during performance of simple clinical tests at the point of care.

An electromechanical gait trainer for restoration of gait in hemiparetic stroke patients: preliminary results.

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Hesse, S; Werner, C; Uhlenbrock, D; von Frankenberg, S; Bardeleben, A; Brandl-Hesse, B

2001-01-01

Modern concepts of gait rehabilitation after stroke favor a task-specific repetitive approach. In practice, the required physical effort of the therapists limits the realization of this approach. Therefore, a mechanized gait trainer enabling nonambulatory patients to have the repetitive practice of a gait-like movement without overstraining therapists was constructed. This preliminary study investigated whether an additional 4-week daily therapy on the gait trainer could improve gait ability in 14 chronic wheelchair-bound hemiparetic subjects. The 4 weeks of physiotherapy and gait-trainer therapy resulted in a relevant improvement of gait ability in all subjects. Velocity, cadence, and stride length improved significantly (p gait trainer seems feasible as an adjunctive tool in gait rehabilitation after stroke; further studies are needed.

Continuous positive airway pressure improves gait control in severe obstructive sleep apnoea: A prospective study.

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Sébastien Baillieul

Full Text Available Severe obstructive sleep apnoea (OSA can lead to neurocognitive alterations, including gait impairments. The beneficial effects of continuous positive airway pressure (CPAP on improving excessive daytime sleepiness and daily functioning have been documented. However, a demonstration of CPAP treatment efficacy on gait control is still lacking. This study aims to test the hypothesis that CPAP improves gait control in severe OSA patients.In this prospective controlled study, twelve severe OSA patients (age = 57.2±8.9 years, body mass index = 27.4±3.1 kg·m-2, apnoea-hypopnoea index = 46.3±11.7 events·h-1 and 10 healthy matched subjects were included. Overground gait parameters were recorded at spontaneous speed and stride time variability, a clinical marker of gait control, was calculated. To assess the role of executive functions in gait and postural control, a dual-task paradigm was applied using a Stroop test as secondary cognitive task. All assessments were performed before and after 8 weeks of CPAP treatment.Before CPAP treatment, OSA patients had significantly larger stride time variability (3.1±1.1% vs 2.1±0.5% and lower cognitive performances under dual task compared to controls. After CPAP treatment, stride time variability was significantly improved and no longer different compared to controls. Cognitive performance under dual task also improved after CPAP treatment.Eight weeks of CPAP treatment improves gait control of severe OSA patients, suggesting morphological and functional cerebral improvements. Our data provide a rationale for further mechanistic studies and the use of gait as a biomarker of OSA brain consequences.

Influence of moderate training on gait and work capacity of fibromyalgia patients: a preliminary field study.

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Tiidus, Peter M; Pierrynowski, Michael; Dawson, Kimberley A

2002-12-01

This field study examined the influence of moderate intensity training on gait patterns and work capacity of individuals with fibromyalgia syndrome (FS). FS is a chronic condition of unknown etiology, characterized by muscle tenderness, pain and stiffness and often accompanied by depression and fatigue which seems to occur primarily in middle aged females. There is no known cure for FS but treatment often includes a prescription of mild exercise. Few studies have evaluated the effectiveness of mild exercise on work capacity and gait patterns in FS patients. Participants were 14 females (age 47.0 ± 7.6 y) who participated in a 10 wk community based aerobic, strength and stretching program designed for FS individuals. Subjects were evaluated pre- and post-program and at a 2 month follow up. Work capacity was estimated by a sub-maximal PWC 170 cycle ergometer test and a Borg perceived exertion scale. Gait was assessed using OptoTrack three dimensional kinematics with 16 channel analogue data acquisition system. Trunk flexibility was also assessed. No significant change in estimated work capacity or flexibility was seen between pre- post- and follow up times. Nevertheless, a significant increase in self selected walking speed (p gait pattern that was sustained in the follow up testing was noted. We had previously also reported a significant improvement in muscle pain and other fibromyalgia symptoms in this population consequent to the training program. It was concluded that mild exercise training that does not influence work capacity or trunk flexibility can nevertheless positively influence gait mechanics and fibromyalgia symptoms in female FS patients.

Self-perceived gait stability modulates the effect of daily life gait quality on prospective falls in older adults.

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Weijer, R H A; Hoozemans, M J M; van Dieën, J H; Pijnappels, M

2018-05-01

Quality of gait during daily life activities and perceived gait stability are both independent risk factors for future falls in older adults. We investigated whether perceived gait stability modulates the association between gait quality and falling in older adults. In this prospective cohort study, we used one-week daily-life trunk acceleration data of 272 adults over 65 years of age. Sample entropy (SE) of the 3D acceleration signals was calculated to quantify daily life gait quality. To quantify perceived gait stability, the level of concern about falling was assessed using the Falls Efficacy Scale international (FES-I) questionnaire and step length, estimated from the accelerometer data. A fall calendar was used to record fall incidence during a six-month follow up period. Logistic regression analyses were performed to study the association between falling and SE, step length or FES-I score, and their interactions. High (i.e., poor) SE in vertical direction was significantly associated with falling. FES-I scores significantly modulated this association, whereas step length did not. Subgroup analyses based on FES-I scores showed that high SE in the vertical direction was a risk factor for falls only in older adults who had a high (i.e. poor) FES-I score. In conclusion, perceived gait stability modulates the association between gait quality and falls in older adults such that an association between gait quality and falling is only present when perceived gait stability is poor. The results of the present study indicate that the effectiveness of interventions for fall prevention, aimed at improving gait quality, may be affected by a modulating effect of perceived gait stability. Results indicate that interventions to reduce falls in older adults might sort most effectiveness in populations with both a poor physiological and psychological status. Copyright © 2018 Elsevier B.V. All rights reserved.

Invariant Gait Continuum Based on the Duty-Factor

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Fihl, Preben; Moeslund, Thomas B.

2008-01-01

contexts and tangent orientations. Input silhouettes are matched to the database using the Hungarian method. We define a classifier based on the dissimilarity between the input silhouettes and the gait actions of the database. This classification achieves an overall recognition rate of 87.1% on a diverse...

Gait variability: methods, modeling and meaning

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Hausdorff Jeffrey M

2005-07-01

Full Text Available Abstract The study of gait variability, the stride-to-stride fluctuations in walking, offers a complementary way of quantifying locomotion and its changes with aging and disease as well as a means of monitoring the effects of therapeutic interventions and rehabilitation. Previous work has suggested that measures of gait variability may be more closely related to falls, a serious consequence of many gait disorders, than are measures based on the mean values of other walking parameters. The Current JNER series presents nine reports on the results of recent investigations into gait variability. One novel method for collecting unconstrained, ambulatory data is reviewed, and a primer on analysis methods is presented along with a heuristic approach to summarizing variability measures. In addition, the first studies of gait variability in animal models of neurodegenerative disease are described, as is a mathematical model of human walking that characterizes certain complex (multifractal features of the motor control's pattern generator. Another investigation demonstrates that, whereas both healthy older controls and patients with a higher-level gait disorder walk more slowly in reduced lighting, only the latter's stride variability increases. Studies of the effects of dual tasks suggest that the regulation of the stride-to-stride fluctuations in stride width and stride time may be influenced by attention loading and may require cognitive input. Finally, a report of gait variability in over 500 subjects, probably the largest study of this kind, suggests how step width variability may relate to fall risk. Together, these studies provide new insights into the factors that regulate the stride-to-stride fluctuations in walking and pave the way for expanded research into the control of gait and the practical application of measures of gait variability in the clinical setting.

Grey matter, an endophenotype for schizophrenia? A voxel-based morphometry study in siblings of patients with schizophrenia

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van der Velde, Jorien; Gromann, Paula M.; Swart, Marte; de Haan, Lieuwe; Wiersma, Durk; Bruggeman, Richard; Krabbendam, Lydia; Aleman, André

2015-01-01

Background Grey matter, both volume and concentration, has been proposed as an endophenotype for schizophrenia given a number of reports of grey matter abnormalities in relatives of patients with schizophrenia. However, previous studies on grey matter abnormalities in relatives have produced inconsistent results. The aim of the present study was to examine grey matter differences between controls and siblings of patients with schizophrenia and to examine whether the age, genetic loading or subclinical psychotic symptoms of selected individuals could explain the previously reported inconsistencies. Methods We compared the grey matter volume and grey matter concentration of healthy siblings of patients with schizophrenia and healthy controls matched for age, sex and education using voxel-based morphometry (VBM). Furthermore, we selected subsamples based on age (< 30 yr), genetic loading and subclinical psychotic symptoms to examine whether this would lead to different results. Results We included 89 siblings and 69 controls in our study. The results showed that siblings and controls did not differ significantly on grey matter volume or concentration. Furthermore, specifically selecting participants based on age, genetic loading or subclinical psychotic symptoms did not alter these findings. Limitations The main limitation was that subdividing the sample resulted in smaller samples for the subanalyses. Furthermore, we used MRI data from 2 different scanner sites. Conclusion These results indicate that grey matter measured through VBM might not be a suitable endophenotype for schizophrenia. PMID:25768029

Apolipoprotein E4 Allele and Gait Performance in Mild Cognitive Impairment: Results From the Gait and Brain Study.

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Sakurai, Ryota; Montero-Odasso, Manuel

2017-11-09

The apolipoprotein E polymorphism ε4 allele (ApoE4) and gait impairment are both known risk factors for developing cognitive decline and dementia. However, it is unclear the interrelationship between these factors, particularly among older adults with mild cognitive impairment (MCI) who are considered as prodromal for Alzheimer's disease. This study aimed to determine whether ApoE4 carrier individuals with MCI may experience greater impairment in gait performance. Fifty-six older adults with MCI from the "Gait and Brain Study" who were identified as either ApoE4 carriers (n = 20) or non-ApoE4 carriers (n = 36) with 1 year of follow-up were included. Gait variability, the main outcome variable, was assessed as stride time variability with an electronic walkway. Additional gait variables and cognitive performance (mini-mental state examination [MMSE] and Montreal Cognitive Assessment [MoCA]) were also recorded. Covariates included age, sex, education level, body mass index, and number of comorbidities. Baseline characteristics were similar for both groups. Repeated measures analysis of covariance showed that gait stride time and stride length variabilities significantly increased in ApoE4 carriers but was maintained in the non-ApoE4 carriers. Similarly, ApoE4 carriers showed greater decrease in MMSE score at follow-up. In this sample of older adults with MCI, the presence of at least one copy of ApoE4 was associated with the development of both increased gait variability and cognitive decline during 1 year of follow-up. ApoE4 genotype might be considered as a potential mediator of decline in mobility function in MCI; future studies with larger samples are needed to confirm our preliminary findings. © The Author 2017. 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.

Reliability and validity of a smartphone-based assessment of gait parameters across walking speed and smartphone locations: Body, bag, belt, hand, and pocket.

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Silsupadol, Patima; Teja, Kunlanan; Lugade, Vipul

2017-10-01

The assessment of spatiotemporal gait parameters is a useful clinical indicator of health status. Unfortunately, most assessment tools require controlled laboratory environments which can be expensive and time consuming. As smartphones with embedded sensors are becoming ubiquitous, this technology can provide a cost-effective, easily deployable method for assessing gait. Therefore, the purpose of this study was to assess the reliability and validity of a smartphone-based accelerometer in quantifying spatiotemporal gait parameters when attached to the body or in a bag, belt, hand, and pocket. Thirty-four healthy adults were asked to walk at self-selected comfortable, slow, and fast speeds over a 10-m walkway while carrying a smartphone. Step length, step time, gait velocity, and cadence were computed from smartphone-based accelerometers and validated with GAITRite. Across all walking speeds, smartphone data had excellent reliability (ICC 2,1 ≥0.90) for the body and belt locations, with bag, hand, and pocket locations having good to excellent reliability (ICC 2,1 ≥0.69). Correlations between the smartphone-based and GAITRite-based systems were very high for the body (r=0.89, 0.98, 0.96, and 0.87 for step length, step time, gait velocity, and cadence, respectively). Similarly, Bland-Altman analysis demonstrated that the bias approached zero, particularly in the body, bag, and belt conditions under comfortable and fast speeds. Thus, smartphone-based assessments of gait are most valid when placed on the body, in a bag, or on a belt. The use of a smartphone to assess gait can provide relevant data to clinicians without encumbering the user and allow for data collection in the free-living environment. Copyright © 2017 Elsevier B.V. All rights reserved.

Voxel-Based Neighborhood for Spatial Shape Pattern Classification of Lidar Point Clouds with Supervised Learning

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Victoria Plaza-Leiva

2017-03-01

Full Text Available Improving the effectiveness of spatial shape features classification from 3D lidar data is very relevant because it is largely used as a fundamental step towards higher level scene understanding challenges of autonomous vehicles and terrestrial robots. In this sense, computing neighborhood for points in dense scans becomes a costly process for both training and classification. This paper proposes a new general framework for implementing and comparing different supervised learning classifiers with a simple voxel-based neighborhood computation where points in each non-overlapping voxel in a regular grid are assigned to the same class by considering features within a support region defined by the voxel itself. The contribution provides offline training and online classification procedures as well as five alternative feature vector definitions based on principal component analysis for scatter, tubular and planar shapes. Moreover, the feasibility of this approach is evaluated by implementing a neural network (NN method previously proposed by the authors as well as three other supervised learning classifiers found in scene processing methods: support vector machines (SVM, Gaussian processes (GP, and Gaussian mixture models (GMM. A comparative performance analysis is presented using real point clouds from both natural and urban environments and two different 3D rangefinders (a tilting Hokuyo UTM-30LX and a Riegl. Classification performance metrics and processing time measurements confirm the benefits of the NN classifier and the feasibility of voxel-based neighborhood.

Voxel-Based Neighborhood for Spatial Shape Pattern Classification of Lidar Point Clouds with Supervised Learning.

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Plaza-Leiva, Victoria; Gomez-Ruiz, Jose Antonio; Mandow, Anthony; García-Cerezo, Alfonso

2017-03-15

Improving the effectiveness of spatial shape features classification from 3D lidar data is very relevant because it is largely used as a fundamental step towards higher level scene understanding challenges of autonomous vehicles and terrestrial robots. In this sense, computing neighborhood for points in dense scans becomes a costly process for both training and classification. This paper proposes a new general framework for implementing and comparing different supervised learning classifiers with a simple voxel-based neighborhood computation where points in each non-overlapping voxel in a regular grid are assigned to the same class by considering features within a support region defined by the voxel itself. The contribution provides offline training and online classification procedures as well as five alternative feature vector definitions based on principal component analysis for scatter, tubular and planar shapes. Moreover, the feasibility of this approach is evaluated by implementing a neural network (NN) method previously proposed by the authors as well as three other supervised learning classifiers found in scene processing methods: support vector machines (SVM), Gaussian processes (GP), and Gaussian mixture models (GMM). A comparative performance analysis is presented using real point clouds from both natural and urban environments and two different 3D rangefinders (a tilting Hokuyo UTM-30LX and a Riegl). Classification performance metrics and processing time measurements confirm the benefits of the NN classifier and the feasibility of voxel-based neighborhood.

Energy Expenditure of Trotting Gait Under Different Gait Parameters

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Chen, Xian-Bao; Gao, Feng

2017-07-01

Robots driven by batteries are clean, quiet, and can work indoors or in space. However, the battery endurance is a great problem. A new gait parameter design energy saving strategy to extend the working hours of the quadruped robot is proposed. A dynamic model of the robot is established to estimate and analyze the energy expenditures during trotting. Given a trotting speed, optimal stride frequency and stride length can minimize the energy expenditure. However, the relationship between the speed and the optimal gait parameters is nonlinear, which is difficult for practical application. Therefore, a simplified gait parameter design method for energy saving is proposed. A critical trotting speed of the quadruped robot is found and can be used to decide the gait parameters. When the robot is travelling lower than this speed, it is better to keep a constant stride length and change the cycle period. When the robot is travelling higher than this speed, it is better to keep a constant cycle period and change the stride length. Simulations and experiments on the quadruped robot show that by using the proposed gait parameter design approach, the energy expenditure can be reduced by about 54% compared with the 100 mm stride length under 500 mm/s speed. In general, an energy expenditure model based on the gait parameter of the quadruped robot is built and the trotting gait parameters design approach for energy saving is proposed.

Gait disorders in the elderly and dual task gait analysis: a new approach for identifying motor phenotypes.

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Auvinet, Bernard; Touzard, Claude; Montestruc, François; Delafond, Arnaud; Goeb, Vincent

2017-01-31

Gait disorders and gait analysis under single and dual-task conditions are topics of great interest, but very few studies have looked for the relevance of gait analysis under dual-task conditions in elderly people on the basis of a clinical approach. An observational study including 103 patients (mean age 76.3 ± 7.2, women 56%) suffering from gait disorders or memory impairment was conducted. Gait analysis under dual-task conditions was carried out for all patients. Brain MRI was performed in the absence of contra-indications. Three main gait variables were measured: walking speed, stride frequency, and stride regularity. For each gait variable, the dual task cost was computed and a quartile analysis was obtained. Nonparametric tests were used for all the comparisons (Wilcoxon, Kruskal-Wallis, Fisher or Chi 2 tests). Four clinical subgroups were identified: gait instability (45%), recurrent falls (29%), memory impairment (18%), and cautious gait (8%). The biomechanical severity of these subgroups was ordered according to walking speed and stride regularity under both conditions, from least to most serious as follows: memory impairment, gait instability, recurrent falls, cautious gait (p < 0.01 for walking speed, p = 0.05 for stride regularity). According to the established diagnoses of gait disorders, 5 main pathological subgroups were identified (musculoskeletal diseases (n = 11), vestibular diseases (n = 6), mild cognitive impairment (n = 24), central nervous system pathologies, (n = 51), and without diagnosis (n = 8)). The dual task cost for walking speed, stride frequency and stride regularity were different among these subgroups (p < 0.01). The subgroups mild cognitive impairment and central nervous system pathologies both showed together a higher dual task cost for each variable compared to the other subgroups combined (p = 0.01). The quartile analysis of dual task cost for stride frequency and stride regularity

DTI Analysis of Presbycusis Using Voxel-Based Analysis.

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Ma, W; Li, M; Gao, F; Zhang, X; Shi, L; Yu, L; Zhao, B; Chen, W; Wang, G; Wang, X

2016-07-14

Presbycusis is the most common sensory deficit in the aging population. A recent study reported using a DTI-based tractography technique to identify a lack of integrity in a portion of the auditory pathway in patients with presbycusis. The aim of our study was to investigate the white matter pathology of patients with presbycusis by using a voxel-based analysis that is highly sensitive to local intensity changes in DTI data. Fifteen patients with presbycusis and 14 age- and sex-matched healthy controls were scanned on a 3T scanner. Fractional anisotropy, mean diffusivity, axial diffusivity, and radial diffusivity were obtained from the DTI data. Intergroup statistics were implemented on these measurements, which were transformed to Montreal Neurological Institute coordinates by using a nonrigid image registration method called large deformation diffeomorphic metric mapping. Increased axial diffusivity, radial diffusivity, and mean diffusivity and decreased fractional anisotropy were found near the right-side hearing-related areas in patients with presbycusis. Increased radial diffusivity and mean diffusivity were also found near a language-related area (Broca area) in patients with presbycusis. Our findings could be important for exploring reliable imaging evidence of presbycusis and could complement an ROI-based approach. © 2016 American Society of Neuroradiology.

Gait Analysis of Symptomatic Flatfoot in Children: An Observational Study.

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Kim, Ha Yong; Shin, Hyuck Soo; Ko, Jun Hyuck; Cha, Yong Han; Ahn, Jae Hoon; Hwang, Jae Yeon

2017-09-01

Flatfoot deformity is a lever arm disease that incurs kinetic inefficiency during gait. The purpose of this study was to measure the degree of kinetic inefficiency by comparing the gait analysis data of a flatfoot group with a normal control group. The patient group consisted of 26 children (21 males and 5 females) with symptomatic flatfoot. They were examined with gait analysis between May 2005 and February 2014. Exclusion criteria were patients with secondary flatfoot caused by neuromuscular disorders, tarsal coalition, vertical talus, or others. Patients' mean age was 9.5 years (range, 7 to 13 years). The gait analysis data of the study group and the normal control group were compared. The mean vertical ground reaction force (GRF) in the push-off phase was 0.99 for the patient group and 1.15 for the control group ( p push-off phase was 0.89 for the patient group and 1.27 for the control group ( p push-off phase was 1.38 for the patient group and 2.52 for the control group ( p push-off phase during gait. Symptomatic flatfeet had a moment inefficiency of 30% and power inefficiency of 45% during gait compared to feet with preserved medial longitudinal arches.

Voxel-based lesion-symptom mapping of stroke lesions underlying somatosensory deficits

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Sarah Meyer

2016-01-01

Full Text Available The aim of this study was to investigate the relationship between stroke lesion location and the resulting somatosensory deficit. We studied exteroceptive and proprioceptive somatosensory symptoms and stroke lesions in 38 patients with first-ever acute stroke. The Erasmus modified Nottingham Sensory Assessment was used to clinically evaluate somatosensory functioning in the arm and hand within the first week after stroke onset. Additionally, more objective measures such as the perceptual threshold of touch and somatosensory evoked potentials were recorded. Non-parametric voxel-based lesion-symptom mapping was performed to investigate lesion contribution to different somatosensory deficits in the upper limb. Additionally, structural connectivity of brain areas that demonstrated the strongest association with somatosensory symptoms was determined, using probabilistic fiber tracking based on diffusion tensor imaging data from a healthy age-matched sample. Voxels with a significant association to somatosensory deficits were clustered in two core brain regions: the central parietal white matter, also referred to as the sensory component of the superior thalamic radiation, and the parietal operculum close to the insular cortex, representing the secondary somatosensory cortex. Our objective recordings confirmed findings from clinical assessments. Probabilistic tracking connected the first region to thalamus, internal capsule, brain stem, postcentral gyrus, cerebellum, and frontal pathways, while the second region demonstrated structural connections to thalamus, insular and primary somatosensory cortex. This study reveals that stroke lesions in the sensory fibers of the superior thalamocortical radiation and the parietal operculum are significantly associated with multiple exteroceptive and proprioceptive deficits in the arm and hand.

Voxel-based lesion-symptom mapping of stroke lesions underlying somatosensory deficits.

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Meyer, Sarah; Kessner, Simon S; Cheng, Bastian; Bönstrup, Marlene; Schulz, Robert; Hummel, Friedhelm C; De Bruyn, Nele; Peeters, Andre; Van Pesch, Vincent; Duprez, Thierry; Sunaert, Stefan; Schrooten, Maarten; Feys, Hilde; Gerloff, Christian; Thomalla, Götz; Thijs, Vincent; Verheyden, Geert

2016-01-01

The aim of this study was to investigate the relationship between stroke lesion location and the resulting somatosensory deficit. We studied exteroceptive and proprioceptive somatosensory symptoms and stroke lesions in 38 patients with first-ever acute stroke. The Erasmus modified Nottingham Sensory Assessment was used to clinically evaluate somatosensory functioning in the arm and hand within the first week after stroke onset. Additionally, more objective measures such as the perceptual threshold of touch and somatosensory evoked potentials were recorded. Non-parametric voxel-based lesion-symptom mapping was performed to investigate lesion contribution to different somatosensory deficits in the upper limb. Additionally, structural connectivity of brain areas that demonstrated the strongest association with somatosensory symptoms was determined, using probabilistic fiber tracking based on diffusion tensor imaging data from a healthy age-matched sample. Voxels with a significant association to somatosensory deficits were clustered in two core brain regions: the central parietal white matter, also referred to as the sensory component of the superior thalamic radiation, and the parietal operculum close to the insular cortex, representing the secondary somatosensory cortex. Our objective recordings confirmed findings from clinical assessments. Probabilistic tracking connected the first region to thalamus, internal capsule, brain stem, postcentral gyrus, cerebellum, and frontal pathways, while the second region demonstrated structural connections to thalamus, insular and primary somatosensory cortex. This study reveals that stroke lesions in the sensory fibers of the superior thalamocortical radiation and the parietal operculum are significantly associated with multiple exteroceptive and proprioceptive deficits in the arm and hand.

Reduction of freezing of gait in Parkinson's disease by repetitive robot-assisted treadmill training: a pilot study

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Friedman Joseph H

2010-10-01

Full Text Available Abstract Background Parkinson's disease is a chronic, neurodegenerative disease characterized by gait abnormalities. Freezing of gait (FOG, an episodic inability to generate effective stepping, is reported as one of the most disabling and distressing parkinsonian symptoms. While there are no specific therapies to treat FOG, some external physical cues may alleviate these types of motor disruptions. The purpose of this study was to examine the potential effect of continuous physical cueing using robot-assisted sensorimotor gait training on reducing FOG episodes and improving gait. Methods Four individuals with Parkinson's disease and FOG symptoms received ten 30-minute sessions of robot-assisted gait training (Lokomat to facilitate repetitive, rhythmic, and alternating bilateral lower extremity movements. Outcomes included the FOG-Questionnaire, a clinician-rated video FOG score, spatiotemporal measures of gait, and the Parkinson's Disease Questionnaire-39 quality of life measure. Results All participants showed a reduction in FOG both by self-report and clinician-rated scoring upon completion of training. Improvements were also observed in gait velocity, stride length, rhythmicity, and coordination. Conclusions This pilot study suggests that robot-assisted gait training may be a feasible and effective method of reducing FOG and improving gait. Videotaped scoring of FOG has the potential advantage of providing additional data to complement FOG self-report.

Increased Grey Matter Associated with Long-Term Sahaja Yoga Meditation: A Voxel-Based Morphometry Study.

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Sergio Elías Hernández

Full Text Available To investigate regional differences in grey matter volume associated with the practice of Sahaja Yoga Meditation.Twenty three experienced practitioners of Sahaja Yoga Meditation and twenty three non-meditators matched on age, gender and education level, were scanned using structural Magnetic Resonance Imaging and their grey matter volume were compared using Voxel-Based Morphometry.Grey matter volume was larger in meditators relative to non-meditators across the whole brain. In addition, grey matter volume was larger in several predominantly right hemispheric regions: in insula, ventromedial orbitofrontal cortex, inferior temporal and parietal cortices as well as in left ventrolateral prefrontal cortex and left insula. No areas with larger grey matter volume were found in non-meditators relative to meditators.The study shows that long-term practice of Sahaja Yoga Meditation is associated with larger grey matter volume overall, and with regional enlargement in several right hemispheric cortical and subcortical brain regions that are associated with sustained attention, self-control, compassion and interoceptive perception. The increased grey matter volume in these attention and self-control mediating regions suggests use-dependent enlargement with regular practice of this meditation.

Increased Grey Matter Associated with Long-Term Sahaja Yoga Meditation: A Voxel-Based Morphometry Study.

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Hernández, Sergio Elías; Suero, José; Barros, Alfonso; González-Mora, José Luis; Rubia, Katya

2016-01-01

To investigate regional differences in grey matter volume associated with the practice of Sahaja Yoga Meditation. Twenty three experienced practitioners of Sahaja Yoga Meditation and twenty three non-meditators matched on age, gender and education level, were scanned using structural Magnetic Resonance Imaging and their grey matter volume were compared using Voxel-Based Morphometry. Grey matter volume was larger in meditators relative to non-meditators across the whole brain. In addition, grey matter volume was larger in several predominantly right hemispheric regions: in insula, ventromedial orbitofrontal cortex, inferior temporal and parietal cortices as well as in left ventrolateral prefrontal cortex and left insula. No areas with larger grey matter volume were found in non-meditators relative to meditators. The study shows that long-term practice of Sahaja Yoga Meditation is associated with larger grey matter volume overall, and with regional enlargement in several right hemispheric cortical and subcortical brain regions that are associated with sustained attention, self-control, compassion and interoceptive perception. The increased grey matter volume in these attention and self-control mediating regions suggests use-dependent enlargement with regular practice of this meditation.

Change in gait after high tibial osteotomy: A systematic review and meta-analysis.

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Lee, Seung Hoon; Lee, O-Sung; Teo, Seow Hui; Lee, Yong Seuk

2017-09-01

We conducted a meta-analysis to analyze how high tibial osteotomy (HTO) changes gait and focused on the following questions: (1) How does HTO change basic gait variables? (2) How does HTO change the gait variables in the knee joint? Twelve articles were included in the final analysis. A total of 383 knees was evaluated. There were 237 open wedge (OW) and 143 closed wedge (CW) HTOs. There were 4 level II studies and 8 level III studies. All studies included gait analysis and compared pre- and postoperative values. One study compared CWHTO and unicompartmental knee arthroplasty (UKA), and another study compared CWHTO and OWHTO. Five studies compared gait variables with those of healthy controls. One study compared operated limb gait variables with those in the non-operated limb. Gait speed, stride length, knee adduction moment, and lateral thrust were major variables assessed in 2 or more studies. Walking speed increased and stride length was increased or similar after HTO compared to the preoperative value in basic gait variables. Knee adduction moment and lateral thrust were decreased after HTO compared to the preoperative knee joint gait variables. Change in co-contraction of the medial side muscle after surgery differed depending on the degree of frontal plane alignment. The relationship between change in knee adduction moment and change in mechanical axis angle was controversial. Based on our systematic review and meta-analysis, walking speed and stride length increased after HTO. Knee adduction moment and lateral thrust decreased after HTO compared to the preoperative values of gait variables in the knee joint. Copyright © 2017 Elsevier B.V. All rights reserved.

A voxel-based morphometry and diffusion tensor imaging analysis of asymptomatic Parkinson's disease-related G2019S LRRK2 mutation carriers

NARCIS (Netherlands)

Thaler, A.; Artzi, M.; Mirelman, A.; Jacob, Y.; Helmich, R.C.G.; Nuenen, B.F.L. van; Gurevich, T.; Orr-Urtreger, A.; Marder, K.; Bressman, S.; Bloem, B.R.; Hendler, T.; Giladi, N.; Bashat, D. Ben; et al.,

2014-01-01

BACKGROUND: Patients with Parkinson's disease have reduced gray matter volume and fractional anisotropy in both cortical and sub-cortical structures, yet changes in the pre-motor phase of the disease are unknown. METHODS: A comprehensive imaging study using voxel-based morphometry and diffusion

Accuracy and reproducibility of voxel based superimposition of cone beam computed tomography models on the anterior cranial base and the zygomatic arches.

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Nada, Rania M; Maal, Thomas J J; Breuning, K Hero; Bergé, Stefaan J; Mostafa, Yehya A; Kuijpers-Jagtman, Anne Marie

2011-02-09

Superimposition of serial Cone Beam Computed Tomography (CBCT) scans has become a valuable tool for three dimensional (3D) assessment of treatment effects and stability. Voxel based image registration is a newly developed semi-automated technique for superimposition and comparison of two CBCT scans. The accuracy and reproducibility of CBCT superimposition on the anterior cranial base or the zygomatic arches using voxel based image registration was tested in this study. 16 pairs of 3D CBCT models were constructed from pre and post treatment CBCT scans of 16 adult dysgnathic patients. Each pair was registered on the anterior cranial base three times and on the left zygomatic arch twice. Following each superimposition, the mean absolute distances between the 2 models were calculated at 4 regions: anterior cranial base, forehead, left and right zygomatic arches. The mean distances between the models ranged from 0.2 to 0.37 mm (SD 0.08-0.16) for the anterior cranial base registration and from 0.2 to 0.45 mm (SD 0.09-0.27) for the zygomatic arch registration. The mean differences between the two registration zones ranged between 0.12 to 0.19 mm at the 4 regions. Voxel based image registration on both zones could be considered as an accurate and a reproducible method for CBCT superimposition. The left zygomatic arch could be used as a stable structure for the superimposition of smaller field of view CBCT scans where the anterior cranial base is not visible.

A comparative study of the effects of trunk exercise program in aquatic and land-based therapy on gait in hemiplegic stroke patients

OpenAIRE

Park, Byoung-Sun; Noh, Ji-Woong; Kim, Mee-Young; Lee, Lim-Kyu; Yang, Seung-Min; Lee, Won-Deok; Shin, Yong-Sub; Kim, Ju-Hyun; Lee, Jeong-Uk; Kwak, Taek-Yong; Lee, Tae-Hyun; Park, Jaehong; Kim, Junghwan

2016-01-01

[Purpose] The purpose of this study was to compare the effects of aquatic and land-based trunk exercise program on gait in stroke patients. [Subjects and Methods] The subjects were 28 hemiplegic stroke patients (20 males, 8 females). The subjects performed a trunk exercise program for a total of four weeks. [Results] Walking speed and cycle, stance phase and stride length of the affected side, and the symmetry index of the stance phase significantly improved after the aquatic and land-based t...

From Cortical and Subcortical Grey Matter Abnormalities to Neurobehavioral Phenotype of Angelman Syndrome: A Voxel-Based Morphometry Study.

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Gayane Aghakhanyan

Full Text Available Angelman syndrome (AS is a rare neurogenetic disorder due to loss of expression of maternal ubiquitin-protein ligase E3A (UBE3A gene. It is characterized by severe developmental delay, speech impairment, movement or balance disorder and typical behavioral uniqueness. Affected individuals show normal magnetic resonance imaging (MRI findings, although mild dysmyelination may be observed. In this study, we adopted a quantitative MRI analysis with voxel-based morphometry (FSL-VBM method to investigate disease-related changes in the cortical/subcortical grey matter (GM structures. Since 2006 to 2013 twenty-six AS patients were assessed by our multidisciplinary team. From those, sixteen AS children with confirmed maternal 15q11-q13 deletions (mean age 7.7 ± 3.6 years and twenty-one age-matched controls were recruited. The developmental delay and motor dysfunction were assessed using Bayley III and Gross Motor Function Measure (GMFM. Principal component analysis (PCA was applied to the clinical and neuropsychological datasets. High-resolution T1-weighted images were acquired and FSL-VBM approach was applied to investigate differences in the local GM volume and to correlate clinical and neuropsychological changes in the regional distribution of GM. We found bilateral GM volume loss in AS compared to control children in the striatum, limbic structures, insular and orbitofrontal cortices. Voxel-wise correlation analysis with the principal components of the PCA output revealed a strong relationship with GM volume in the superior parietal lobule and precuneus on the left hemisphere. The anatomical distribution of cortical/subcortical GM changes plausibly related to several clinical features of the disease and may provide an important morphological underpinning for clinical and neurobehavioral symptoms in children with AS.

Markedly impaired bilateral coordination of gait in post-stroke patients: Is this deficit distinct from asymmetry? A cohort study

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van Lummel Rob C

2011-05-01

Full Text Available Abstract Background Multiple aspects of gait are typically impaired post-stroke. Asymmetric gait is common as a consequence of unilateral brain lesions. The relationship between the resulting asymmetric gait and impairments in the ability to properly coordinate the reciprocal stepping activation of the legs is not clear. The objective of this exploratory study is to quantify the effects of hemiparesis on two putatively independent aspects of the bilateral coordination of gait to gain insight into mechanisms and their relationship and to assess their potential as clinical markers. Methods Twelve ambulatory stroke patients and age-matched healthy adults wore a tri-axial piezo-resistive accelerometer and walked back and forth along a straight path in a hall at a comfortable walking speed during 2 minutes. Gait speed, gait asymmetry (GA, and aspects of the bilateral coordination of gait (BCG were determined. Bilateral coordination measures included the left-right stepping phase for each stride φi, consistency in the phase generation φ_CV, accuracy in the phase generation φ_ABS, and Phase Coordination Index (PCI, a combination of accuracy and consistency of the phase generation. Results Group differences (p Conclusions In ambulatory post-stroke patients, two gait coordination properties, GA and PCI, are markedly impaired. Although these features are not related to each other in healthy controls, they are strongly related in stroke patients, which is a novel finding. A measurement approach based on body-fixed sensors apparently may provide sensitive markers that can be used for clinical assessment and for enhancing rehabilitation targeting in post-stroke patients.

Markedly impaired bilateral coordination of gait in post-stroke patients: Is this deficit distinct from asymmetry? A cohort study

Science.gov (United States)

2011-01-01

Background Multiple aspects of gait are typically impaired post-stroke. Asymmetric gait is common as a consequence of unilateral brain lesions. The relationship between the resulting asymmetric gait and impairments in the ability to properly coordinate the reciprocal stepping activation of the legs is not clear. The objective of this exploratory study is to quantify the effects of hemiparesis on two putatively independent aspects of the bilateral coordination of gait to gain insight into mechanisms and their relationship and to assess their potential as clinical markers. Methods Twelve ambulatory stroke patients and age-matched healthy adults wore a tri-axial piezo-resistive accelerometer and walked back and forth along a straight path in a hall at a comfortable walking speed during 2 minutes. Gait speed, gait asymmetry (GA), and aspects of the bilateral coordination of gait (BCG) were determined. Bilateral coordination measures included the left-right stepping phase for each stride φi, consistency in the phase generation φ_CV, accuracy in the phase generation φ_ABS, and Phase Coordination Index (PCI), a combination of accuracy and consistency of the phase generation. Results Group differences (p stroke patients (r = 0.94; p stroke patients, two gait coordination properties, GA and PCI, are markedly impaired. Although these features are not related to each other in healthy controls, they are strongly related in stroke patients, which is a novel finding. A measurement approach based on body-fixed sensors apparently may provide sensitive markers that can be used for clinical assessment and for enhancing rehabilitation targeting in post-stroke patients. PMID:21545703

Intensive gait training with rhythmic auditory stimulation in individuals with chronic hemiparetic stroke: a pilot randomized controlled study.

Science.gov (United States)

Cha, Yuri; Kim, Young; Hwang, Sujin; Chung, Yijung

2014-01-01

Motor relearning protocols should involve task-oriented movement, focused attention, and repetition of desired movements. To investigate the effect of intensive gait training with rhythmic auditory stimulation on postural control and gait performance in individuals with chronic hemiparetic stroke. Twenty patients with chronic hemiparetic stroke participated in this study. Subjects in the Rhythmic auditory stimulation training group (10 subjects) underwent intensive gait training with rhythmic auditory stimulation for a period of 6 weeks (30 min/day, five days/week), while those in the control group (10 subjects) underwent intensive gait training for the same duration. Two clinical measures, Berg balance scale and stroke specific quality of life scale, and a 2-demensional gait analysis system, were used as outcome measure. To provide rhythmic auditory stimulation during gait training, the MIDI Cuebase musical instrument digital interface program and a KM Player version 3.3 was utilized for this study. Intensive gait training with rhythmic auditory stimulation resulted in significant improvement in scores on the Berg balance scale, gait velocity, cadence, stride length and double support period in affected side, and stroke specific quality of life scale compared with the control group after training. Findings of this study suggest that intensive gait training with rhythmic auditory stimulation improves balance and gait performance as well as quality of life, in individuals with chronic hemiparetic stroke.

INFLUENCE OF MODERATE TRAINING ON GAIT AND WORK CAPACITY OF FIBROMYALGIA PATIENTS: A PRELIMINARY FIELD STUDY

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Michael Pierrynowski

2002-12-01

Full Text Available This field study examined the influence of moderate intensity training on gait patterns and work capacity of individuals with fibromyalgia syndrome (FS. FS is a chronic condition of unknown etiology, characterized by muscle tenderness, pain and stiffness and often accompanied by depression and fatigue which seems to occur primarily in middle aged females. There is no known cure for FS but treatment often includes a prescription of mild exercise. Few studies have evaluated the effectiveness of mild exercise on work capacity and gait patterns in FS patients. Participants were 14 females (age 47.0± 7.6 y who participated in a 10 wk community based aerobic, strength and stretching program designed for FS individuals. Subjects were evaluated pre- and post-program and at a 2 month follow up. Work capacity was estimated by a sub-maximal PWC 170 cycle ergometer test and a Borg perceived exertion scale. Gait was assessed using OptoTrack three dimensional kinematics with 16 channel analogue data acquisition system. Trunk flexibility was also assessed. No significant change in estimated work capacity or flexibility was seen between pre- post- and follow up times. Nevertheless, a significant increase in self selected walking speed (p < 0.05 and a trend toward a more normal gait pattern that was sustained in the follow up testing was noted. We had previously also reported a significant improvement in muscle pain and other fibromyalgia symptoms in this population consequent to the training program. It was concluded that mild exercise training that does not influence work capacity or trunk flexibility can nevertheless positively influence gait mechanics and fibromyalgia symptoms in female FS patients

Topographic deformation patterns of knee cartilage after exercises with high knee flexion: an in vivo 3D MRI study using voxel-based analysis at 3T

International Nuclear Information System (INIS)

Horng, Annie; Stockinger, M.; Notohamiprodjo, M.; Raya, J.G.; Pietschmann, M.; Hoehne-Hueckstaedt, U.; Glitsch, U.; Ellegast, R.; Hering, K.G.; Glaser, C.

2015-01-01

To implement a novel voxel-based technique to identify statistically significant local cartilage deformation and analyze in-vivo topographic knee cartilage deformation patterns using a voxel-based thickness map approach for high-flexion postures. Sagittal 3T 3D-T1w-FLASH-WE-sequences of 10 healthy knees were acquired before and immediately after loading (kneeling/squatting/heel sitting/knee bends). After cartilage segmentation, 3D-reconstruction and 3D-registration, colour-coded deformation maps were generated by voxel-based subtraction of loaded from unloaded datasets to visualize cartilage thickness changes in all knee compartments. Compression areas were found bifocal at the peripheral medial/caudolateral patella, both posterior femoral condyles and both anterior/central tibiae. Local cartilage thickening were found adjacent to the compression areas. Significant local strain ranged from +13 to -15 %. Changes were most pronounced after squatting, least after knee bends. Shape and location of deformation areas varied slightly with the loading paradigm, but followed a similar pattern consistent between different individuals. Voxel-based deformation maps identify individual in-vivo load-specific and posture-associated strain distribution in the articular cartilage. The data facilitate understanding individual knee loading properties and contribute to improve biomechanical 3 models. They lay a base to investigate the relationship between cartilage degeneration patterns in common osteoarthritis and areas at risk of cartilage wear due to mechanical loading in work-related activities. (orig.)

Topographic deformation patterns of knee cartilage after exercises with high knee flexion: an in vivo 3D MRI study using voxel-based analysis at 3T

Energy Technology Data Exchange (ETDEWEB)

Horng, Annie; Stockinger, M.; Notohamiprodjo, M. [Ludwig-Maximilians-University Hospital Munich, Institute for Clinical Radiology, Munich (Germany); Raya, J.G. [New York University Langone Medical Center, Center for Biomedical Imaging, New York, NY (United States); Pietschmann, M. [Ludwig-Maximilians-University Hospital Munich, Department of Orthopedic Surgery, Munich (Germany); Hoehne-Hueckstaedt, U.; Glitsch, U.; Ellegast, R. [Institute for Occupational Safety and Health of the German Social Accident Insurance (IFA), Sankt Augustin (Germany); Hering, K.G. [Miner' s Hospital, Department of Diagnostic Radiology, Dortmund (Germany); Glaser, C. [Ludwig-Maximilians-University Hospital Munich, Institute for Clinical Radiology, Munich (Germany); RZM Zentrum, Munich (Germany)

2015-06-01

To implement a novel voxel-based technique to identify statistically significant local cartilage deformation and analyze in-vivo topographic knee cartilage deformation patterns using a voxel-based thickness map approach for high-flexion postures. Sagittal 3T 3D-T1w-FLASH-WE-sequences of 10 healthy knees were acquired before and immediately after loading (kneeling/squatting/heel sitting/knee bends). After cartilage segmentation, 3D-reconstruction and 3D-registration, colour-coded deformation maps were generated by voxel-based subtraction of loaded from unloaded datasets to visualize cartilage thickness changes in all knee compartments. Compression areas were found bifocal at the peripheral medial/caudolateral patella, both posterior femoral condyles and both anterior/central tibiae. Local cartilage thickening were found adjacent to the compression areas. Significant local strain ranged from +13 to -15 %. Changes were most pronounced after squatting, least after knee bends. Shape and location of deformation areas varied slightly with the loading paradigm, but followed a similar pattern consistent between different individuals. Voxel-based deformation maps identify individual in-vivo load-specific and posture-associated strain distribution in the articular cartilage. The data facilitate understanding individual knee loading properties and contribute to improve biomechanical 3 models. They lay a base to investigate the relationship between cartilage degeneration patterns in common osteoarthritis and areas at risk of cartilage wear due to mechanical loading in work-related activities. (orig.)

Structural brain alterations in hemifacial spasm: A voxel-based morphometry and diffusion tensor imaging study.

Science.gov (United States)

Tu, Ye; Yu, Tian; Wei, Yongxu; Sun, Kun; Zhao, Weiguo; Yu, Buwei

2016-02-01

Hemifacial spasm (HFS) is characterized by involuntary, irregular clonic or tonic movement of muscles innervated by the facial nerve. We evaluated structural reorganization in brain gray matter and white matter and whether neuroplasticity is linked to clinical features in HFS patients. High-resolution structural magnetic resonance imaging and diffusion tensor imaging data were acquired by 3.0 T MRI from 42 patients with HFS and 30 healthy subjects. The severity of the spasm was assessed according to Jankovic disability rating scale. Voxel-based morphometry (VBM) and tract-based spatial statistics (TBSS) analysis were performed to identify regional grey matter volume (GMV) changes and whole-brain microstructural integrity disruption measured by fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD) and radial diffusivity (RD). The VBM analysis showed that patients with HFS reduced GMV in the right inferior parietal lobule and increased GMV in the cerebellar lobule VIII, when compared with healthy subjects. Furthermore, within the HFS disease group, GMV decreased with the disease duration in the right inferior parietal lobule. TBSS did not identify group differences in diffusivity parameters. While no white matter integrity disruption was detected in the brain of patients with HFS, our study identified evident GMV changes in brain areas which were known to be involved in motor control. Our results suggest that HFS, a chronic neurovascular conflict disease, is related to structural reorganization in the brain. Copyright © 2015 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

Gait Recognition Using Wearable Motion Recording Sensors

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Davrondzhon Gafurov

2009-01-01

Full Text Available This paper presents an alternative approach, where gait is collected by the sensors attached to the person's body. Such wearable sensors record motion (e.g. acceleration of the body parts during walking. The recorded motion signals are then investigated for person recognition purposes. We analyzed acceleration signals from the foot, hip, pocket and arm. Applying various methods, the best EER obtained for foot-, pocket-, arm- and hip- based user authentication were 5%, 7%, 10% and 13%, respectively. Furthermore, we present the results of our analysis on security assessment of gait. Studying gait-based user authentication (in case of hip motion under three attack scenarios, we revealed that a minimal effort mimicking does not help to improve the acceptance chances of impostors. However, impostors who know their closest person in the database or the genders of the users can be a threat to gait-based authentication. We also provide some new insights toward the uniqueness of gait in case of foot motion. In particular, we revealed the following: a sideway motion of the foot provides the most discrimination, compared to an up-down or forward-backward directions; and different segments of the gait cycle provide different level of discrimination.

Cerebral Reorganization in Subacute Stroke Survivors after Virtual Reality-Based Training: A Preliminary Study

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Xiang Xiao

2017-01-01

Full Text Available Background. Functional magnetic resonance imaging (fMRI is a promising method for quantifying brain recovery and investigating the intervention-induced changes in corticomotor excitability after stroke. This study aimed to evaluate cortical reorganization subsequent to virtual reality-enhanced treadmill (VRET training in subacute stroke survivors. Methods. Eight participants with ischemic stroke underwent VRET for 5 sections per week and for 3 weeks. fMRI was conducted to quantify the activity of selected brain regions when the subject performed ankle dorsiflexion. Gait speed and clinical scales were also measured before and after intervention. Results. Increased activation in the primary sensorimotor cortex of the lesioned hemisphere and supplementary motor areas of both sides for the paretic foot (p<0.01 was observed postintervention. Statistically significant improvements were observed in gait velocity (p<0.05. The change in voxel counts in the primary sensorimotor cortex of the lesioned hemisphere is significantly correlated with improvement of 10 m walk time after VRET (r=−0.719. Conclusions. We observed improved walking and increased activation in cortical regions of stroke survivors after VRET training. Moreover, the cortical recruitment was associated with better walking function. Our study suggests that cortical networks could be a site of plasticity, and their recruitment may be one mechanism of training-induced recovery of gait function in stroke. This trial is registered with ChiCTR-IOC-15006064.

Postural Control and Gait Performance in the Diabetic Peripheral Neuropathy: A Systematic Review.

Science.gov (United States)

Mustapa, Amirah; Justine, Maria; Mohd Mustafah, Nadia; Jamil, Nursuriati; Manaf, Haidzir

2016-01-01

Purpose. The aim of this paper is to review the published studies on the characteristics of impairments in the postural control and gait performance in diabetic peripheral neuropathy (DPN). Methods. A review was performed by obtaining publication of all papers reporting on the postural control and gait performance in DPN from Google Scholar, Ovid, SAGE, Springerlink, Science Direct (SD), EBSCO Discovery Service, and Web of Science databases. The keywords used for searching were "postural control," "balance," "gait performance," "diabetes mellitus," and "diabetic peripheral neuropathy." Results. Total of 4,337 studies were hit in the search. 1,524 studies were screened on their titles and citations. Then, 79 studies were screened on their abstract. Only 38 studies were eligible to be selected: 17 studies on postural control and 21 studies on the gait performance. Most previous researches were found to have strong evidence of postural control impairments and noticeable gait deficits in DPN. Deterioration of somatosensory, visual, and vestibular systems with the pathologic condition of diabetes on cognitive impairment causes further instability of postural and gait performance in DPN. Conclusions. Postural instability and gait imbalance in DPN may contribute to high risk of fall incidence, especially in the geriatric population. Thus, further works are crucial to highlight this fact in the hospital based and community adults.

The Relevance Voxel Machine (RVoxM): A Self-Tuning Bayesian Model for Informative Image-Based Prediction

DEFF Research Database (Denmark)

Sabuncu, Mert R.; Van Leemput, Koen

2012-01-01

This paper presents the relevance voxel machine (RVoxM), a dedicated Bayesian model for making predictions based on medical imaging data. In contrast to the generic machine learning algorithms that have often been used for this purpose, the method is designed to utilize a small number of spatially...

A Voxel-Based Morphometric MRI Study in Young Adults with Borderline Personality Disorder.

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Xinhu Jin

Full Text Available Increasing evidence has documented subtle changes in brain morphology and function in patients with borderline personality disorder (BPD. However, results of magnetic resonance imaging volumetry in patients with BPD are inconsistent. In addition, few researchers using voxel-based morphometry (VBM have focused on attachment and childhood trauma in BPD. This preliminary study was performed to investigate structural brain changes and their relationships to attachment and childhood trauma in a homogenous sample of young adults with BPD.We examined 34 young adults with BPD and 34 healthy controls (HCs to assess regionally specific differences in gray matter volume (GMV and gray matter concentration (GMC. Multiple regressions between brain volumes measured by VBM and attachment style questionnaire (ASQ and childhood trauma questionnaire (CTQ scores were performed.Compared with HCs, subjects with BPD showed significant bilateral increases in GMV in the middle cingulate cortex (MCC/posterior cingulate cortex (PCC/precuneus. GMC did not differ significantly between groups. In multiple regression models, ASQ insecure attachment scores were correlated negatively with GMV in the precuneus/MCC and middle occipital gyrus in HCs, HCs with more severe insecure attachment showed smaller volumes in precuneus/MCC and middle occipital gyrus, whereas no negative correlations between insecure attachment and GMV in any region were found in BPD group. In addition, CTQ total scores were not correlated with GMV in any region in the two groups respectively.Our findings fit with those of previous reports of larger precuneus GMV in patients with BPD, and suggest that GMV in the precuneus/MCC and middle occipital gyrus is associated inversely with insecure attachment style in HCs. Our finding of increased GMV in the MCC and PCC in patients with BPD compared with HCs has not been reported in previous VBM studies.

Description of spatio-temporal gait parameters in elderly people and their association with history of falls: results of the population-based cross-sectional KORA-Age study.

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Thaler-Kall, Kathrin; Peters, Annette; Thorand, Barbara; Grill, Eva; Autenrieth, Christine S; Horsch, Alexander; Meisinger, Christa

2015-03-25

In this epidemiological study we described the characteristics of spatio-temporal gait parameters among a representative, population-based sample of 890 community-dwelling people aged 65 to 90 years. In addition, we investigated the associations between certain gait parameters and a history of falls in study participants. In descriptive analyses spatio-temporal gait parameters were assessed according to history of falls, frailty, multimorbidity, gender, multiple medication use, disability status, and age group. Logistic regression models were calculated to examine the association between gait velocity and stride length with a history of falls (at least one fall in the last 12 month). Data on gait were collected on an electronic walkway on which participants walked at their usual pace. We found significant differences within gait parameters when stratifying by frailty, multimorbidity, disability and multiple medication use as well as age (cut point 75 years) and sex, with p history of falls, only stride length showed a significant difference (p falls in men aged older than 74 years (OR 1.34 (CI: 1.05-1.70 per 10 cm decrease)), while this was neither the case for women of similar age nor for men or women aged 65 to 74 years. A decreased walking speed was not associated with falls. Age, frailty, multimorbidity, disability, history of falls, sex, and multiple medication use show an association with different gait parameters measured during gait assessment on an electronic walkway in elderly people. Furthermore, stride length is a good indicator to differentiate fallers from non-fallers in older men from the general population.

A Voxel-Based Morphometry Study of the Brain of University Students Majoring in Music and Nonmusic Disciplines.

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Sato, Kanako; Kirino, Eiji; Tanaka, Shoji

2015-01-01

The brain changes flexibly due to various experiences during the developmental stages of life. Previous voxel-based morphometry (VBM) studies have shown volumetric differences between musicians and nonmusicians in several brain regions including the superior temporal gyrus, sensorimotor areas, and superior parietal cortex. However, the reported brain regions depend on the study and are not necessarily consistent. By VBM, we investigated the effect of musical training on the brain structure by comparing university students majoring in music with those majoring in nonmusic disciplines. All participants were right-handed healthy Japanese females. We divided the nonmusic students into two groups and therefore examined three groups: music expert (ME), music hobby (MH), and nonmusic (NM) group. VBM showed that the ME group had the largest gray matter volumes in the right inferior frontal gyrus (IFG; BA 44), left middle occipital gyrus (BA 18), and bilateral lingual gyrus. These differences are considered to be caused by neuroplasticity during long and continuous musical training periods because the MH group showed intermediate volumes in these regions.

Construction of a voxel model from CT images with density derived from CT numbers

International Nuclear Information System (INIS)

Cheng Mengyun; Zeng Qin; Cao Ruifen; Li Gui; Zheng Huaqing; Huang Shanqing; Song Gang; Wu Yican

2010-01-01

The voxel models representing human anatomy have been developed to calculate dose distribution in human body, while the density is the most important physical property of voxel model. Traditionally, when creating the Monte Carlo input files, the average tissue parameters recommended in ICRP report were used to assign each voxel in the existing voxel models. However, as each tissue consists of many voxels in which voxels are different in their densities, the method of assigning average tissue parameters doesn't take account of the voxel's discrepancy, and can't represent human anatomy faithfully. To represent human anatomy more faithfully, a method was implemented to assign each voxel, the density of which was derived from CT number. In order to compare with the traditional method, we have constructed two models from a same cadaver specimen date set. A CT-based pelvic voxel model called Pelvis-CT model, was constructed, the densities of which were derived from the CT numbers. A color photograph-based pelvic voxel model called Pelvis-Photo model, was also constructed, the densities of which were taken from ICRP Publication. The CT images and color photographs were obtained from the same female cadaver specimen. The Pelvis-CT and Pelvis-Photo models were ported into Monte Carlo code MCNP to calculate the conversion coefficients from kerma free-in-air to absorbed dose for external monoenergetic photon beams with energies of 0.1, 1 and 10 MeV under anterior-posterior (AP) geometries. The results were compared with those of given in ICRP74. Differences of up to 50% were observed between conversion coefficients of Pelvis-CT and Pelvis-Photo models, moreover the discrepancies decreased for the photon beams with higher energies. The overall trend of conversion coefficients of the Pelvis-CT model were agreed well with that of ICRP74 data. (author)

Robot-Crawler: Statically Balanced Gaits

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S. Parasuraman

2012-12-01

Full Text Available This paper presents a new statically balanced walking technique for a robot-crawler. The gait design and the control of the robot crawler aim to achieve stability while walking. This statically balanced gait has to be designed in a different fashion to a wheeled robot, as there are discrete changes in the support of the robot when its legs are lifted or placed on the ground. The stability of the robot depends on how the legs are positioned relative to the body and also on the sequence and timing with which the legs are lifted and placed. In order to reduce the risk of stability loss while walking, a measure for the robot stability (so-called stability margin is typically used in the gait and motion planning. In this paper different biological behaviours of four-legged animals are studied and mapped on a quad-legrobot-crawler. Experiments were carried out on the forward walking gaits of lizards and horses. Based on these results, the stability margins of different gaits are discussed and compared.

Effect of phantom voxelization in CT simulations

International Nuclear Information System (INIS)

Goertzen, Andrew L.; Beekman, Freek J.; Cherry, Simon R.

2002-01-01

In computer simulations of x-ray CT systems one can either use continuous geometrical descriptions for phantoms or a voxelized representation. The voxelized approach allows arbitrary phantoms to be defined without being confined to geometrical shapes. The disadvantage of the voxelized approach is that inherent errors are introduced due to the phantom voxelization. To study effects of phantom discretization, analytical CT simulations were run for a fan-beam geometry with phantom voxel sizes ranging from 0.0625 to 2 times the reconstructed pixel size and noise levels corresponding to 10 3 -10 7 photons per detector pixel prior to attenuation. The number of rays traced per detector element was varied from 1 to 16. Differences in the filtered backprojection images caused by changing the phantom matrix sizes and number of rays traced were assessed by calculating the difference between reconstructions based on the finest matrix and coarser matrix simulations. In noise free simulations, all phantom matrix sizes produced a measurable difference in comparison with the finest phantom matrix used. When even a small amount of noise was added to the projection data, the differences due to the phantom discretization were masked by the noise, and in all cases there was almost no improvement by using a phantom matrix that was more than twice as fine as the reconstruction matrix. No substantial improvement was achieved by tracing more than 4 rays per detector pixel

Effects of conventional overground gait training and a gait trainer with partial body weight support on spatiotemporal gait parameters of patients after stroke

OpenAIRE

Park, Byoung-Sun; Kim, Mee-Young; Lee, Lim-Kyu; Yang, Seung-Min; Lee, Won-Deok; Noh, Ji-Woong; Shin, Yong-Sub; Kim, Ju-Hyun; Lee, Jeong-Uk; Kwak, Taek-Yong; Lee, Tae-Hyun; Kim, Ju-Young; Kim, Junghwan

2015-01-01

[Purpose] The purpose of this study was to confirm the effects of both conventional overground gait training (CGT) and a gait trainer with partial body weight support (GTBWS) on spatiotemporal gait parameters of patients with hemiparesis following chronic stroke. [Subjects and Methods] Thirty stroke patients were alternately assigned to one of two treatment groups, and both groups underwent CGT and GTBWS. [Results] The functional ambulation classification on the affected side improved signifi...

An Ambulatory Method of Identifying Anterior Cruciate Ligament Reconstructed Gait Patterns

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Matthew R. Patterson

2014-01-01

Full Text Available The use of inertial sensors to characterize pathological gait has traditionally been based on the calculation of temporal and spatial gait variables from inertial sensor data. This approach has proved successful in the identification of gait deviations in populations where substantial differences from normal gait patterns exist; such as in Parkinsonian gait. However, it is not currently clear if this approach could identify more subtle gait deviations, such as those associated with musculoskeletal injury. This study investigates whether additional analysis of inertial sensor data, based on quantification of gyroscope features of interest, would provide further discriminant capability in this regard. The tested cohort consisted of a group of anterior cruciate ligament reconstructed (ACL-R females and a group of non-injured female controls, each performed ten walking trials. Gait performance was measured simultaneously using inertial sensors and an optoelectronic marker based system. The ACL-R group displayed kinematic and kinetic deviations from the control group, but no temporal or spatial deviations. This study demonstrates that quantification of gyroscope features can successfully identify changes associated with ACL-R gait, which was not possible using spatial or temporal variables. This finding may also have a role in other clinical applications where small gait deviations exist.

Physical Inactivity Predicts Slow Gait Speed in an Elderly Multi-Ethnic Cohort Study: The Northern Manhattan Study.

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Willey, Joshua Z; Moon, Yeseon P; Kulick, Erin R; Cheung, Ying Kuen; Wright, Clinton B; Sacco, Ralph L; Elkind, Mitchell S V

2017-01-01

Gait speed is associated with multiple adverse outcomes of aging. We hypothesized that physical inactivity would be prospectively inversely associated with gait speed independently of white matter hyperintensity volume and silent brain infarcts on MRI. Participants in the Northern Manhattan Study MRI sub-study had physical activity assessed when they were enrolled into the study. A mean of 5 years after the MRI, participants had gait speed measured via a timed 5-meter walk test. Physical inactivity was defined as reporting no leisure-time physical activity. Multi-variable logistic and quantile regression was performed to examine the associations between physical inactivity and future gait speed adjusted for confounders. Among 711 participants with MRI and gait speed measures (62% women, 71% Hispanic, mean age 74.1 ± 8.4), the mean gait speed was 1.02 ± 0.26 m/s. Physical inactivity was associated with a greater odds of gait speed in the lowest quartile (Physical inactivity is associated with slower gait speed independently of osteoarthritis, grip strength, and subclinical ischemic brain injury. Modifying sedentary behavior poses a target for interventions aimed at reducing decline in mobility. © 2017 S. Karger AG, Basel.

Gait performance and foot pressure distribution during wearable robot-assisted gait in elderly adults.

Science.gov (United States)

Lee, Su-Hyun; Lee, Hwang-Jae; Chang, Won Hyuk; Choi, Byung-Ok; Lee, Jusuk; Kim, Jeonghun; Ryu, Gyu-Ha; Kim, Yun-Hee

2017-11-28

A robotic exoskeleton device is an intelligent system designed to improve gait performance and quality of life for the wearer. Robotic technology has developed rapidly in recent years, and several robot-assisted gait devices were developed to enhance gait function and activities of daily living in elderly adults and patients with gait disorders. In this study, we investigated the effects of the Gait-enhancing Mechatronic System (GEMS), a new wearable robotic hip-assist device developed by Samsung Electronics Co, Ltd., Korea, on gait performance and foot pressure distribution in elderly adults. Thirty elderly adults who had no neurological or musculoskeletal abnormalities affecting gait participated in this study. A three-dimensional (3D) motion capture system, surface electromyography and the F-Scan system were used to collect data on spatiotemporal gait parameters, muscle activity and foot pressure distribution under three conditions: free gait without robot assistance (FG), robot-assisted gait with zero torque (RAG-Z) and robot-assisted gait (RAG). We found increased gait speed, cadence, stride length and single support time in the RAG condition. Reduced rectus femoris and medial gastrocnemius muscle activity throughout the terminal stance phase and reduced effort of the medial gastrocnemius muscle throughout the pre-swing phase were also observed in the RAG condition. In addition, walking with the assistance of GEMS resulted in a significant increase in foot pressure distribution, specifically in maximum force and peak pressure of the total foot, medial masks, anterior masks and posterior masks. The results of the present study reveal that GEMS may present an alternative way of restoring age-related changes in gait such as gait instability with muscle weakness, reduced step force and lower foot pressure in elderly adults. In addition, GEMS improved gait performance by improving push-off power and walking speed and reducing muscle activity in the lower

Gait disorder as a predictor of spatial learning and memory impairment in aged mice

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Xin Wang

2017-01-01

Full Text Available Objective To investigate whether gait dysfunction is a predictor of severe spatial learning and memory impairment in aged mice. Methods A total of 100 12-month-old male mice that had no obvious abnormal motor ability and whose Morris water maze performances were not significantly different from those of two-month-old male mice were selected for the study. The selected aged mice were then divided into abnormal or normal gait groups according to the results from the quantitative gait assessment. Gaits of aged mice were defined as abnormal when the values of quantitative gait parameters were two standard deviations (SD lower or higher than those of 2-month-old male mice. Gait parameters included stride length, variability of stride length, base of support, cadence, and average speed. After nine months, mice exhibiting severe spatial learning and memory impairment were separated from mice with mild or no cognitive dysfunction. The rate of severe spatial learning and memory impairment in the abnormal and normal gait groups was tested by a chi-square test and the correlation between gait dysfunction and decline in cognitive function was tested using a diagnostic test. Results The 12-month-old aged mice were divided into a normal gait group (n = 75 and an abnormal gait group (n = 25. Nine months later, three mice in the normal gait group and two mice in the abnormal gait group had died. The remaining mice were subjected to the Morris water maze again, and 17 out of 23 mice in the abnormal gait group had developed severe spatial learning and memory impairment, including six with stride length deficits, 15 with coefficient of variation (CV in stride length, two with base of support (BOS deficits, five with cadence dysfunction, and six with average speed deficits. In contrast, only 15 out of 72 mice in the normal gait group developed severe spatial learning and memory impairment. The rate of severe spatial learning and memory impairment was

Effects of circular gait training on balance, balance confidence in patients with stroke: a pilot study.

Science.gov (United States)

Park, Shin-Kyu; Kim, Sung-Jin; Yoon, Tak Yong; Lee, Suk-Min

2018-05-01

[Purpose] This study aimed to investigate the effects of circular gait training on balance and balance confidence in patients with stroke. [Subjects and Methods] Fifteen patients with stroke were randomly divided into either the circular gait training (CGT) group (n=8) or the straight gait training (SGT) group (n=7). Both groups had conventional therapy that adhered to the neurodevelopmental treatment (NDT) approach, for 30 min. In addition, the CGT group performed circular gait training, and the SGT group practiced straight gait training for 30 min. Each intervention was applied for 1 h, 5 days a week, for 2 weeks. Berg Balance Scale (BBS), Timed Up and Go (TUG) test, and Activities-specific Balance Confidence (ABC) scale were used to test balance and balance confidence. [Results] After the intervention, both groups showed significant increases in balance and balance confidence. Significant improvements in the balance of the CGT group compared with the SGT group were observed at post-assessment. [Conclusion] This study showed that circular gait training significantly improves balance in patients with stroke.

Accuracy and reproducibility of voxel based superimposition of cone beam computed tomography models on the anterior cranial base and the zygomatic arches.

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Rania M Nada

Full Text Available Superimposition of serial Cone Beam Computed Tomography (CBCT scans has become a valuable tool for three dimensional (3D assessment of treatment effects and stability. Voxel based image registration is a newly developed semi-automated technique for superimposition and comparison of two CBCT scans. The accuracy and reproducibility of CBCT superimposition on the anterior cranial base or the zygomatic arches using voxel based image registration was tested in this study. 16 pairs of 3D CBCT models were constructed from pre and post treatment CBCT scans of 16 adult dysgnathic patients. Each pair was registered on the anterior cranial base three times and on the left zygomatic arch twice. Following each superimposition, the mean absolute distances between the 2 models were calculated at 4 regions: anterior cranial base, forehead, left and right zygomatic arches. The mean distances between the models ranged from 0.2 to 0.37 mm (SD 0.08-0.16 for the anterior cranial base registration and from 0.2 to 0.45 mm (SD 0.09-0.27 for the zygomatic arch registration. The mean differences between the two registration zones ranged between 0.12 to 0.19 mm at the 4 regions. Voxel based image registration on both zones could be considered as an accurate and a reproducible method for CBCT superimposition. The left zygomatic arch could be used as a stable structure for the superimposition of smaller field of view CBCT scans where the anterior cranial base is not visible.

Does robot-assisted gait training ameliorate gait abnormalities in multiple sclerosis? A pilot randomized-control trial.

Science.gov (United States)

Straudi, S; Benedetti, M G; Venturini, E; Manca, M; Foti, C; Basaglia, N

2013-01-01

Gait disorders are common in multiple sclerosis (MS) and lead to a progressive reduction of function and quality of life. Test the effects of robot-assisted gait rehabilitation in MS subjects through a pilot randomized-controlled study. We enrolled MS subjects with Expanded Disability Status Scale scores within 4.5-6.5. The experimental group received 12 robot-assisted gait training sessions over 6 weeks. The control group received the same amount of conventional physiotherapy. Outcomes measures were both biomechanical assessment of gait, including kinematics and spatio-temporal parameters, and clinical test of walking endurance (six-minute walk test) and mobility (Up and Go Test). 16 subjects (n = 8 experimental group, n = 8 control group) were included in the final analysis. At baseline the two groups were similar in all variables, except for step length. Data showed walking endurance, as well as spatio-temporal gait parameters improvements after robot-assisted gait training. Pelvic antiversion and reduced hip extension during terminal stance ameliorated after aforementioned intervention. Robot-assisted gait training seems to be effective in increasing walking competency in MS subjects. Moreover, it could be helpful in restoring the kinematic of the hip and pelvis.

A Wearable Magneto-Inertial System for Gait Analysis (H-Gait: Validation on Normal Weight and Overweight/Obese Young Healthy Adults

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Valentina Agostini

2017-10-01

Full Text Available Background: Wearable magneto-inertial sensors are being increasingly used to obtain human motion measurements out of the lab, although their performance in applications requiring high accuracy, such as gait analysis, are still a subject of debate. The aim of this work was to validate a gait analysis system (H-Gait based on magneto-inertial sensors, both in normal weight (NW and overweight/obese (OW subjects. The validation is performed against a reference multichannel recording system (STEP32, providing direct measurements of gait timings (through foot-switches and joint angles in the sagittal plane (through electrogoniometers. Methods: Twenty-two young male subjects were recruited for the study (12 NW, 10 OW. After positioning body-fixed sensors of both systems, each subject was asked to walk, at a self-selected speed, over a 14-m straight path for 12 trials. Gait signals were recorded, at the same time, with the two systems. Spatio-temporal parameters, ankle, knee, and hip joint kinematics were extracted analyzing an average of 89 ± 13 gait cycles from each lower limb. Intraclass correlation coefficient and Bland-Altmann plots were used to compare H-Gait and STEP32 measurements. Changes in gait parameters and joint kinematics of OW with respect NW were also evaluated. Results: The two systems were highly consistent for cadence, while a lower agreement was found for the other spatio-temporal parameters. Ankle and knee joint kinematics is overall comparable. Joint ROMs values were slightly lower for H-Gait with respect to STEP32 for the ankle (by 1.9° for NW, and 1.6° for OW and for the knee (by 4.1° for NW, and 1.8° for OW. More evident differences were found for hip joint, with ROMs values higher for H-Gait (by 6.8° for NW, and 9.5° for OW. NW and OW showed significant differences considering STEP32 (p = 0.0004, but not H-Gait (p = 0.06. In particular, overweight/obese subjects showed a higher cadence (55.0 vs. 52.3 strides/min and a

Potential hippocampal region atrophy in diabetes mellitus type 2. A voxel-based morphometry VSRAD study

International Nuclear Information System (INIS)

Kamiyama, Kazutoshi; Sugihara, Masaki; Wada, Akihiko

2010-01-01

Among diabetes mellitus type 2 (DM2) patients, the frequency of cognitive dysfunction is higher and the relative risk of Alzheimer's disease (AD) is approximately twice that of nondiabetics. Cognitive impairment symptoms of AD are induced by limbic system dysfunction, and an early-stage AD brain without dementia has the potential for atrophy in the hippocampal region. In this study, we estimated potential hippocampal region atrophy in DM2 and pursued the association between DM2 and cognitive impairment/AD. Voxel-based morphometry analysis was performed in 28 diabetics (14 men, 14 women; ages 59-79 years, mean 70.7 years) and 28 sex- and age- matched (±1 year) nondiabetics. Severity of gray matter loss in the hippocampal region and whole brain were investigated. Group analysis was performed using two-tailed unpaired t-test; significance was assumed with less than 1% (P<0.01) of the critical rate. There was a significant difference between diabetics and nondiabetics regarding the severity of hippocampal region atrophy and whole-brain atrophy. Only diabetics showed a positive correlation for severity of hippocampal region atrophy and whole-brain atrophy (rs=0.69, P<0.0001). Aged DM2 patients have the potential for hippocampal region atrophy, and its dysfunction can be related to the expression of a cognitive impairment that resembles AD. (author)

Multiple gait parameters derived from iPod accelerometry predict age-related gait changes

NARCIS (Netherlands)

Kosse, Nienke; Vuillerme, Nicolas; Hortobagyi, Tibor; Lamoth, Claude

Introduction Normative data of how natural aging affects gait can serve as a frame of reference for changes in gait dynamics due to pathologies. Therefore, the present study aims (1) to identify gait variables sensitive to age-related changes in gait over the adult life span using the iPod and (2)

Postural Control and Gait Performance in the Diabetic Peripheral Neuropathy: A Systematic Review

Directory of Open Access Journals (Sweden)

Amirah Mustapa

2016-01-01

Full Text Available Purpose. The aim of this paper is to review the published studies on the characteristics of impairments in the postural control and gait performance in diabetic peripheral neuropathy (DPN. Methods. A review was performed by obtaining publication of all papers reporting on the postural control and gait performance in DPN from Google Scholar, Ovid, SAGE, Springerlink, Science Direct (SD, EBSCO Discovery Service, and Web of Science databases. The keywords used for searching were “postural control,” “balance,” “gait performance,” “diabetes mellitus,” and “diabetic peripheral neuropathy.” Results. Total of 4,337 studies were hit in the search. 1,524 studies were screened on their titles and citations. Then, 79 studies were screened on their abstract. Only 38 studies were eligible to be selected: 17 studies on postural control and 21 studies on the gait performance. Most previous researches were found to have strong evidence of postural control impairments and noticeable gait deficits in DPN. Deterioration of somatosensory, visual, and vestibular systems with the pathologic condition of diabetes on cognitive impairment causes further instability of postural and gait performance in DPN. Conclusions. Postural instability and gait imbalance in DPN may contribute to high risk of fall incidence, especially in the geriatric population. Thus, further works are crucial to highlight this fact in the hospital based and community adults.

Hardware Development and Locomotion Control Strategy for an Over-Ground Gait Trainer: NaTUre-Gaits.

Science.gov (United States)

Luu, Trieu Phat; Low, Kin Huat; Qu, Xingda; Lim, Hup Boon; Hoon, Kay Hiang

2014-01-01

Therapist-assisted body weight supported (TABWS) gait rehabilitation was introduced two decades ago. The benefit of TABWS in functional recovery of walking in spinal cord injury and stroke patients has been demonstrated and reported. However, shortage of therapists, labor-intensiveness, and short duration of training are some limitations of this approach. To overcome these deficiencies, robotic-assisted gait rehabilitation systems have been suggested. These systems have gained attentions from researchers and clinical practitioner in recent years. To achieve the same objective, an over-ground gait rehabilitation system, NaTUre-gaits, was developed at the Nanyang Technological University. The design was based on a clinical approach to provide four main features, which are pelvic motion, body weight support, over-ground walking experience, and lower limb assistance. These features can be achieved by three main modules of NaTUre-gaits: 1) pelvic assistance mechanism, mobile platform, and robotic orthosis. Predefined gait patterns are required for a robotic assisted system to follow. In this paper, the gait pattern planning for NaTUre-gaits was accomplished by an individual-specific gait pattern prediction model. The model generates gait patterns that resemble natural gait patterns of the targeted subjects. The features of NaTUre-gaits have been demonstrated by walking trials with several subjects. The trials have been evaluated by therapists and doctors. The results show that 10-m walking trial with a reduction in manpower. The task-specific repetitive training approach and natural walking gait patterns were also successfully achieved.

Radiation-induced changes in normal-appearing gray matter in patients with nasopharyngeal carcinoma: a magnetic resonance imaging voxel-based morphometry study

International Nuclear Information System (INIS)

Lv, Xiao-Fei; Zheng, Xiao-Li; Zhang, Wei-Dong; Liu, Li-Zhi; Zhang, You-Ming; Chen, Ming-Yuan; Li, Li

2014-01-01

Evidence is accumulating that temporal lobe radiation necrosis in patients with nasopharyngeal carcinoma (NPC) after radiotherapy (RT) could involve gray matter (GM). The purpose of the study was to assess the radiation-induced GM volume differences between NPC patients who had and had not received RT and the effect of time after RT on GM volume differences in those patients who had received RT. We used magnetic resonance imaging voxel-based morphometry (VBM) to assess differences in GM volume between 30 NPC patients with normal-appearing whole-brain GM after RT and 15 control patients with newly diagnosed but not yet medically treated NPC. Correlation analyses were used to investigate the relationship between GM volume changes and time after RT. Patients who had received RT had GM volume decreases in the bilateral superior temporal gyrus, left middle temporal gyrus, right fusiform gyrus, right precentral gyrus, and right inferior parietal lobule (p 100 voxels). Moreover, the correlation analysis indicated that regional GM volume loss in the left superior temporal gyrus, left middle temporal gyrus, and right fusiform gyrus were negatively related to the mean dose to the ipsilateral temporal lobe, respectively. These results indicate that GM volume deficits in bilateral temporal lobes in patients who had received RT might be radiation-induced. Our findings might provide new insight into the pathogenesis of radiation-induced structural damage in normal-appearing brain tissue. Yet this is an exploratory study, whose findings should therefore be taken with caution. (orig.)

MicroCT-Based Skeletal Models for Use in Tomographic Voxel Phantoms for Radiological Protection

International Nuclear Information System (INIS)

Bolch, Wesley

2010-01-01

The University of Florida (UF) proposes to develop two high-resolution image-based skeletal dosimetry models for direct use by ICRP Committee 2's Task Group on Dose Calculation in their forthcoming Reference Voxel Male (RVM) and Reference Voxel Female (RVF) whole-body dosimetry phantoms. These two phantoms are CT-based, and thus do not have the image resolution to delineate and perform radiation transport modeling of the individual marrow cavities and bone trabeculae throughout their skeletal structures. Furthermore, new and innovative 3D microimaging techniques will now be required for the skeletal tissues following Committee 2's revision of the target tissues of relevance for radiogenic bone cancer induction. This target tissue had been defined in ICRP Publication 30 as a 10-(micro)m cell layer on all bone surfaces of trabecular and cortical bone. The revised target tissue is now a 50-(micro)m layer within the marrow cavities of trabecular bone only and is exclusive of the marrow adipocytes. Clearly, this new definition requires the use of 3D microimages of the trabecular architecture not available from past 2D optical studies of the adult skeleton. With our recent acquisition of two relatively young cadavers (males of age 18-years and 40-years), we will develop a series of reference skeletal models that can be directly applied to (1) the new ICRP reference voxel man and female phantoms developed for the ICRP, and (2) pediatric phantoms developed to target the ICRP reference children. Dosimetry data to be developed will include absorbed fractions for internal beta and alpha-particle sources, as well as photon and neutron fluence-to-dose response functions for direct use in external dosimetry studies of the ICRP reference workers and members of the general public

MicroCT-Based Skeletal Models for Use in Tomographic Voxel Phantoms for Radiological Protection

Energy Technology Data Exchange (ETDEWEB)

Bolch, Wesley [Univ. of Florida, Gainesville, FL (United States)

2010-03-30

The University of Florida (UF) proposes to develop two high-resolution image-based skeletal dosimetry models for direct use by ICRP Committee 2’s Task Group on Dose Calculation in their forthcoming Reference Voxel Male (RVM) and Reference Voxel Female (RVF) whole-body dosimetry phantoms. These two phantoms are CT-based, and thus do not have the image resolution to delineate and perform radiation transport modeling of the individual marrow cavities and bone trabeculae throughout their skeletal structures. Furthermore, new and innovative 3D microimaging techniques will now be required for the skeletal tissues following Committee 2’s revision of the target tissues of relevance for radiogenic bone cancer induction. This target tissue had been defined in ICRP Publication 30 as a 10-μm cell layer on all bone surfaces of trabecular and cortical bone. The revised target tissue is now a 50-μm layer within the marrow cavities of trabecular bone only and is exclusive of the marrow adipocytes. Clearly, this new definition requires the use of 3D microimages of the trabecular architecture not available from past 2D optical studies of the adult skeleton. With our recent acquisition of two relatively young cadavers (males of age 18-years and 40-years), we will develop a series of reference skeletal models that can be directly applied to (1) the new ICRP reference voxel man and female phantoms developed for the ICRP, and (2) pediatric phantoms developed to target the ICRP reference children. Dosimetry data to be developed will include absorbed fractions for internal beta and alpha-particle sources, as well as photon and neutron fluence-to-dose response functions for direct use in external dosimetry studies of the ICRP reference workers and members of the general public

Construction of a voxel model from CT images with density derived from CT numbers

International Nuclear Information System (INIS)

Cheng Mengyun; Zeng Qin; Cao Ruifen; Li Gui; Zheng Huaqing; Huang Shanqing; Song Gang; Wu Yican

2011-01-01

The voxel models representing human anatomy have been developed to calculate dose distribution in human body, while the density and elemental composition are the most important physical properties of voxel model. Usually, when creating the Monte Carlo input files, the average tissue densities recommended in ICRP Publication were used to assign each voxel in the existing voxel models. As each tissue consists of many voxels with different densities, the conventional method of average tissue densities failed to take account of the voxel's discrepancy, and therefore could not represent human anatomy faithfully. To represent human anatomy more faithfully, a method was implemented to assign each voxel, the densities of which were derived from CT number. In order to compare with the traditional method, we constructed two models from the cadaver specimen dataset. A CT-based pelvic voxel model called Pelvis-CT model was constructed, the densities of which were derived from the CT numbers. A color photograph-based pelvic voxel model called Pelvis-Photo model was also constructed, the densities of which were taken from ICRP Publication. The CT images and the color photographs were obtained from the same female cadaver specimen. The Pelvis-CT and Pelvis-Photo models were both ported into Monte Carlo code MCNP to calculate the conversion coefficients from kerma free-in-air to absorbed dose for external monoenergetic photon beams with energies of 0.1, 1 and 10 MeV under anterior-posterior (AP) geometry. The results were compared with those of given in ICRP Publication 74. Differences of up to 50% were observed between conversion coefficients of Pelvis-CT and Pelvis- Photo models, moreover the discrepancies decreased for the photon beams with higher energies. The overall trend of conversion coefficients of the Pelvis-CT model agreed well with that of ICRP Publication 74 data. (author)

Automated Gait Analysis Through Hues and Areas (AGATHA): a method to characterize the spatiotemporal pattern of rat gait

Science.gov (United States)

Kloefkorn, Heidi E.; Pettengill, Travis R.; Turner, Sara M. F.; Streeter, Kristi A.; Gonzalez-Rothi, Elisa J.; Fuller, David D.; Allen, Kyle D.

2016-01-01

While rodent gait analysis can quantify the behavioral consequences of disease, significant methodological differences exist between analysis platforms and little validation has been performed to understand or mitigate these sources of variance. By providing the algorithms used to quantify gait, open-source gait analysis software can be validated and used to explore methodological differences. Our group is introducing, for the first time, a fully-automated, open-source method for the characterization of rodent spatiotemporal gait patterns, termed Automated Gait Analysis Through Hues and Areas (AGATHA). This study describes how AGATHA identifies gait events, validates AGATHA relative to manual digitization methods, and utilizes AGATHA to detect gait compensations in orthopaedic and spinal cord injury models. To validate AGATHA against manual digitization, results from videos of rodent gait, recorded at 1000 frames per second (fps), were compared. To assess one common source of variance (the effects of video frame rate), these 1000 fps videos were re-sampled to mimic several lower fps and compared again. While spatial variables were indistinguishable between AGATHA and manual digitization, low video frame rates resulted in temporal errors for both methods. At frame rates over 125 fps, AGATHA achieved a comparable accuracy and precision to manual digitization for all gait variables. Moreover, AGATHA detected unique gait changes in each injury model. These data demonstrate AGATHA is an accurate and precise platform for the analysis of rodent spatiotemporal gait patterns. PMID:27554674

Powered robotic exoskeletons in post-stroke rehabilitation of gait: a scoping review.

Science.gov (United States)

Louie, Dennis R; Eng, Janice J

2016-06-08

Powered robotic exoskeletons are a potential intervention for gait rehabilitation in stroke to enable repetitive walking practice to maximize neural recovery. As this is a relatively new technology for stroke, a scoping review can help guide current research and propose recommendations for advancing the research development. The aim of this scoping review was to map the current literature surrounding the use of robotic exoskeletons for gait rehabilitation in adults post-stroke. Five databases (Pubmed, OVID MEDLINE, CINAHL, Embase, Cochrane Central Register of Clinical Trials) were searched for articles from inception to October 2015. Reference lists of included articles were reviewed to identify additional studies. Articles were included if they utilized a robotic exoskeleton as a gait training intervention for adult stroke survivors and reported walking outcome measures. Of 441 records identified, 11 studies, all published within the last five years, involving 216 participants met the inclusion criteria. The study designs ranged from pre-post clinical studies (n = 7) to controlled trials (n = 4); five of the studies utilized a robotic exoskeleton device unilaterally, while six used a bilateral design. Participants ranged from sub-acute (6 months) stroke. Training periods ranged from single-session to 8-week interventions. Main walking outcome measures were gait speed, Timed Up and Go, 6-min Walk Test, and the Functional Ambulation Category. Meaningful improvement with exoskeleton-based gait training was more apparent in sub-acute stroke compared to chronic stroke. Two of the four controlled trials showed no greater improvement in any walking outcomes compared to a control group in chronic stroke. In conclusion, clinical trials demonstrate that powered robotic exoskeletons can be used safely as a gait training intervention for stroke. Preliminary findings suggest that exoskeletal gait training is equivalent to traditional therapy for chronic stroke

SU-F-BRB-10: A Statistical Voxel Based Normal Organ Dose Prediction Model for Coplanar and Non-Coplanar Prostate Radiotherapy

Energy Technology Data Exchange (ETDEWEB)

Tran, A; Yu, V; Nguyen, D; Woods, K; Low, D; Sheng, K [UCLA, Los Angeles, CA (United States)

2015-06-15

Purpose: Knowledge learned from previous plans can be used to guide future treatment planning. Existing knowledge-based treatment planning methods study the correlation between organ geometry and dose volume histogram (DVH), which is a lossy representation of the complete dose distribution. A statistical voxel dose learning (SVDL) model was developed that includes the complete dose volume information. Its accuracy of predicting volumetric-modulated arc therapy (VMAT) and non-coplanar 4π radiotherapy was quantified. SVDL provided more isotropic dose gradients and may improve knowledge-based planning. Methods: 12 prostate SBRT patients originally treated using two full-arc VMAT techniques were re-planned with 4π using 20 intensity-modulated non-coplanar fields to a prescription dose of 40 Gy. The bladder and rectum voxels were binned based on their distances to the PTV. The dose distribution in each bin was resampled by convolving to a Gaussian kernel, resulting in 1000 data points in each bin that predicted the statistical dose information of a voxel with unknown dose in a new patient without triaging information that may be collectively important to a particular patient. We used this method to predict the DVHs, mean and max doses in a leave-one-out cross validation (LOOCV) test and compared its performance against lossy estimators including mean, median, mode, Poisson and Rayleigh of the voxelized dose distributions. Results: SVDL predicted the bladder and rectum doses more accurately than other estimators, giving mean percentile errors ranging from 13.35–19.46%, 4.81–19.47%, 22.49–28.69%, 23.35–30.5%, 21.05–53.93% for predicting mean, max dose, V20, V35, and V40 respectively, to OARs in both planning techniques. The prediction errors were generally lower for 4π than VMAT. Conclusion: By employing all dose volume information in the SVDL model, the OAR doses were more accurately predicted. 4π plans are better suited for knowledge-based planning than