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Sample records for submentalis muscle emg

  1. Evaluation of jaw and neck muscle activities while chewing using EMG-EMG transfer function and EMG-EMG coherence function analyses in healthy subjects.

    Science.gov (United States)

    Ishii, Tomohiro; Narita, Noriyuki; Endo, Hiroshi

    2016-06-01

    This study aims to quantitatively clarify the physiological features in rhythmically coordinated jaw and neck muscle EMG activities while chewing gum using EMG-EMG transfer function and EMG-EMG coherence function analyses in 20 healthy subjects. The chewing side masseter muscle EMG signal was used as the reference signal, while the other jaw (non-chewing side masseter muscle, bilateral anterior temporal muscles, and bilateral anterior digastric muscles) and neck muscle (bilateral sternocleidomastoid muscles) EMG signals were used as the examined signals in EMG-EMG transfer function and EMG-EMG coherence function analyses. Chewing-related jaw and neck muscle activities were aggregated in the first peak of the power spectrum in rhythmic chewing. The gain in the peak frequency represented the power relationships between jaw and neck muscle activities during rhythmic chewing. The phase in the peak frequency represented the temporal relationships between the jaw and neck muscle activities, while the non-chewing side neck muscle presented a broad range of distributions across jaw closing and opening phases. Coherence in the peak frequency represented the synergistic features in bilateral jaw closing muscles and chewing side neck muscle activities. The coherence and phase in non-chewing side neck muscle activities exhibited a significant negative correlation. From above, the bilateral coordination between the jaw and neck muscle activities is estimated while chewing when the non-chewing side neck muscle is synchronously activated with the jaw closing muscles, while the unilateral coordination is estimated when the non-chewing side neck muscle is irregularly activated in the jaw opening phase. Thus, the occurrence of bilateral or unilateral coordinated features in the jaw and neck muscle activities may correspond to the phase characteristics in the non-chewing side neck muscle activities during rhythmical chewing. Considering these novel findings in healthy subjects, EMG-EMG

  2. Reliability of EMG normalisation methods for upper-limb muscles.

    Science.gov (United States)

    Rota, Samuel; Rogowski, Isabelle; Champely, Stéphane; Hautier, Christophe

    2013-01-01

    The study investigated different electromyographic (EMG) normalisation methods for upper-limb muscles. This assessment aimed at comparing the EMG amplitude and the reliability of EMG values obtained with each method. Eighteen male tennis players completed isometric maximal voluntary contractions and dynamic strength exercises (push-ups and chin-ups) on three separate test sessions over at least 7 days. Surface EMG activity of nine upper body muscles was recorded. For each muscle, an analysis of variance for repeated measures was used to compare maximal EMG amplitudes between test conditions. The intra-class correlation coefficient, the coefficient of variation and the standard error of measurement were calculated to determine the EMG reliability of each condition. On the basis of a compromise between maximal EMG amplitude and high reliability, the chin-ups appeared to be the optimal normalisation method for M. latissimus dorsi, M. posterior deltoid, M. biceps brachii, M. flexor carpi radialis and M. extensor carpi radialis. The push-ups seemed relevant to normalise M. anterior deltoid and M. triceps brachii activity, while isometric maximal voluntary contraction remained the most appropriate method for M. pectoralis major and M. middle deltoid. Thus, original methods are proposed to normalise EMG signal of upper-limb muscles.

  3. Influence of fatigue on hand muscle coordination and EMG-EMG coherence during three-digit grasping.

    Science.gov (United States)

    Danna-Dos Santos, Alessander; Poston, Brach; Jesunathadas, Mark; Bobich, Lisa R; Hamm, Thomas M; Santello, Marco

    2010-12-01

    Fingertip force control requires fine coordination of multiple hand muscles within and across the digits. While the modulation of neural drive to hand muscles as a function of force has been extensively studied, much less is known about the effects of fatigue on the coordination of simultaneously active hand muscles. We asked eight subjects to perform a fatiguing contraction by gripping a manipulandum with thumb, index, and middle fingers while matching an isometric target force (40% maximal voluntary force) for as long as possible. The coordination of 12 hand muscles was quantified as electromyographic (EMG) muscle activation pattern (MAP) vector and EMG-EMG coherence. We hypothesized that muscle fatigue would cause uniform changes in EMG amplitude across all muscles and an increase in EMG-EMG coherence in the higher frequency bands but with an invariant heterogeneous distribution across muscles. Muscle fatigue caused a 12.5% drop in the maximum voluntary contraction force (P muscles increased during the fatiguing contraction (P muscle coordination pattern was used throughout the fatiguing contraction. Last, EMG-EMG coherence (0-35 Hz) was significantly greater at the end than at the beginning of the fatiguing contraction (P muscles. These findings suggest that similar mechanisms are involved for modulating and sustaining digit forces in nonfatiguing and fatiguing contractions, respectively.

  4. Towards optimal multi-channel EMG electrode configurations in muscle force estimation: a high density EMG study.

    NARCIS (Netherlands)

    Staudenmann, D.; Kingma, I.; Stegeman, D.F.; Dieen, J.H. van

    2005-01-01

    Surface EMG is an important tool in biomechanics, kinesiology and neurophysiology. In neurophysiology the concept of high-density EMG (HD-EMG), using two dimensional electrode grids, was developed for the measurement of spatiotemporal activation patterns of the underlying muscle and its motor units

  5. Electromyography (EMG) accuracy compared to muscle biopsy in childhood.

    Science.gov (United States)

    Rabie, Malcolm; Jossiphov, Joseph; Nevo, Yoram

    2007-07-01

    Reports show wide variability of electromyography (EMG) in detecting pediatric neuromuscular disorders. The study's aim was to determine EMG/nerve conduction study accuracy compared to muscle biopsy and final clinical diagnosis, and sensitivity for myopathic motor unit potential detection in childhood. Of 550 EMG/nerve conduction studies performed by the same examiner from a pediatric neuromuscular service, 27 children (ages 6 days to 16 years [10 boys; M:F, 1:1.7]) with muscle biopsies and final clinical diagnoses were compared retrospectively. Final clinical diagnoses were congenital myopathies (5 of 27,18%), nonspecific myopathies (biopsy myopathic, final diagnosis uncertain; 6 of 27, 22%), congenital myasthenic syndrome (3 of 27, 11%), juvenile myasthenia gravis (1 of 27, 4%), arthrogryposis multiplex congenita (2 of 27, 7%), hereditary motor and sensory neuropathy (1 of 27, 4%), bilateral peroneal neuropathies (1 of 27, 4%), and normal (8 of 27, 30%). There were no muscular dystrophy or spinal muscular atrophy patients. EMG/nerve conduction studies had a 74% agreement with final clinical diagnoses and 100% agreement in neurogenic, neuromuscular junction, and normal categories. Muscle biopsies concurred with final diagnoses in 87%, and 100% in myopathic and normal categories. In congenital myasthenic syndrome, muscle biopsies showed mild variation in fiber size in 2 of 3 children and were normal in 1 of 3. EMG sensitivity for detecting myopathic motor unit potentials in myopathies was 4 of 11 (36%), greater over 2 years of age (3 of 4, 75%), compared to infants less than 2 years (1 of 7, 14%), not statistically significant (P = .0879). EMGs false-negative for myopathy in infants EMG detected myopathic motor unit potentials in 40%, with false-negative results neurogenic (20%) or normal (40%). Because our study has no additional tests for active myopathies, for example Duchenne muscular dystrophy genetic testing, our sensitivity for myopathies is lower than if we

  6. Trapezius muscle EMG as predictor of mental stress

    NARCIS (Netherlands)

    Wijsman, J.L.P; Grundlehner, B.; Penders, J.; Hermens, Hermanus J.

    Stress is a growing problem in society and can cause musculoskeletal complaints. It would be useful to measure stress for prevention of stress-related health problems. An experiment is described in which EMG signals of the upper trapezius muscle were measured with a wireless system during three

  7. Muscle networks: Connectivity analysis of EMG activity during postural control

    Science.gov (United States)

    Boonstra, Tjeerd W.; Danna-Dos-Santos, Alessander; Xie, Hong-Bo; Roerdink, Melvyn; Stins, John F.; Breakspear, Michael

    2015-12-01

    Understanding the mechanisms that reduce the many degrees of freedom in the musculoskeletal system remains an outstanding challenge. Muscle synergies reduce the dimensionality and hence simplify the control problem. How this is achieved is not yet known. Here we use network theory to assess the coordination between multiple muscles and to elucidate the neural implementation of muscle synergies. We performed connectivity analysis of surface EMG from ten leg muscles to extract the muscle networks while human participants were standing upright in four different conditions. We observed widespread connectivity between muscles at multiple distinct frequency bands. The network topology differed significantly between frequencies and between conditions. These findings demonstrate how muscle networks can be used to investigate the neural circuitry of motor coordination. The presence of disparate muscle networks across frequencies suggests that the neuromuscular system is organized into a multiplex network allowing for parallel and hierarchical control structures.

  8. Reliability of surface EMG measurements from the suprahyoid muscle complex

    DEFF Research Database (Denmark)

    Kothari, Mohit; Stubbs, Peter William; Pedersen, Asger Roer

    2017-01-01

    of using the suprahyoid muscle complex (SMC) using surface electromyography (sEMG) to assess changes to neural pathways by determining the reliability of measurements in healthy participants over days. Methods: Seventeen healthy participants were recruited. Measurements were performed twice with one week...... between sessions. Single pulse (at 120% and 140% of the resting motor threshold (rMT)) and paired pulse (2 ms and 15 ms paired pulse) transcranial magnetic stimulation (TMS) were used to elicit MEPs in the SMC which were recorded using sEMG. Results: ≈50% of participants (range: 42%-58%; depending...... on stimulus type/intensity) had significantly different MEP values between day 1 and day 2 for single pulse and paired pulse TMS. A large stimulus artefact resulted in MEP responses that could not be assessed in four participants. Conclusions: The assessment of the SMC using sEMG following TMS was poorly...

  9. Further observations on the relationship of EMG and muscle force

    Science.gov (United States)

    Agarwal, G. C.; Cecchini, L. R.; Gottlieb, G. L.

    1972-01-01

    Human skeletal muscle may be regarded as an electro-mechanical transducer. Its physiological input is a neural signal originating at the alpha motoneurons in the spinal cord and its output is force and muscle contraction, these both being dependent on the external load. Some experimental data taken during voluntary efforts around the ankle joint and by direct electrical stimulation of the nerve are described. Some of these experiments are simulated by an analog model, the input of which is recorded physiological soleus muscle EMG. The output is simulated foot torque. Limitations of a linear model and effect of some nonlinearities are discussed.

  10. Effect of Selective Muscle Training Using Visual EMG Biofeedback on Infraspinatus and Posterior Deltoid

    OpenAIRE

    Lim One-bin; Kim Jeong-ah; Song Si-jeong; Cynn Heon-seock; Yi Chung-hwi

    2014-01-01

    We investigated the effects of visual electromyography (EMG) biofeedback during side-lying shoulder external rotation exercise on the EMG amplitude for the posterior deltoid, infraspinatus, and infraspinatus/posterior deltoid EMG activity ratio. Thirty-one asymptomatic subjects were included. Subjects performed side-lying shoulder external rotation exercise with and without visual EMG biofeedback. Surface EMG was used to collect data from the posterior deltoid and infraspinatus muscles. The v...

  11. Improving EMG-based muscle force estimation by using a high-density EMG grid and principal component analysis.

    NARCIS (Netherlands)

    Staudenmann, D.; Kingma, I.; Daffertshofer, A.; Stegeman, D.F.; Dieen, J.H. van

    2006-01-01

    The accuracy of predictions of muscle force based on electromyography (EMG) is an important issue in biomechanics and kinesiology. Since human skeletal muscles show a high diversity and heterogeneity in their fiber architecture, it is difficult to properly align electrodes to the muscle fiber

  12. Influence on muscle oxygenation to EMG parameters at different skeletal muscle contraction

    Science.gov (United States)

    Zhang, Li; Song, Gaoqing

    2010-02-01

    The purpose of this study is to investigate the influence of muscle oxygenation on EMG parameters during isometric and incremental exercises and to observe the relationship between EMG parameters and muscle oxygenation. Twelve rowers took part in the tests. Near infrared spectrometer was utilized for measurements of muscle oxygenation on lateral quadriceps. sEMG measurement is performed for EMG parameters during isometric and incremental exercises. Results indicated that Oxy-Hb decrease significantly correlated with IEMG, E/T ratio and frequency of impulse signal during 1/3 MVC and 2/3 MVC isometric exercise, and it is also correlated with IEMG, E/T ratio and frequency of impulse signal. Increase of IEMG occurred at the time after Oxy-Hb decrease during incremental exercise and highly correlated with BLa. It is concluded that no matter how heavy the intensity is, Oxy-Hb dissociation may play an important role in affecting EMG parameters of muscle fatigue during isometric exercise. 2) EMG parameters may be influenced by Oxy-Hb dissociation and blood lactate concentration during dynamic exercise.

  13. EMG-force relation in the first dorsal interosseous muscle of patients with amyotrophic lateral sclerosis.

    Science.gov (United States)

    Jahanmiri-Nezhad, Faezeh; Hu, Xiaogang; Suresh, Nina L; Rymer, William Z; Zhou, Ping

    2014-01-01

    The relationship between surface electromyography (EMG) and muscle force is essential to assess muscle function and its deficits. However, few studies have explored the EMG-force relation in patients with amyotrophic lateral sclerosis (ALS). The purpose of this study was to examine the EMG-force relation in ALS subjects and its alteration in comparison with healthy control subjects. Surface EMG and force signals were recorded while 10 ALS and 10 age-matched healthy control subjects produced isometric voluntary contractions in the first dorsal interosseous (FDI) muscle over the full range of activation. A linear fit of the EMG-force relation was evaluated through the normalized root mean square error (RMSE) between the experimental and predicted EMG amplitudes. The EMG-force relation was compared between the ALS and the healthy control subjects. With a linear fit, the normalized RMSE between the experimental and predicted EMG amplitudes was 9.6 ± 3.6% for the healthy control subjects and 12.3 ± 8.0% for the ALS subjects. The slope of the linear fit was 2.9 ± 2.2 μVN-1 for the ALS subjects and was significantly shallower (p 0.05). A linear fit can be used to well describe the EMG-force relation for the FDI muscle of both ALS and healthy control subjects. A variety of processes may work together in ALS that can adversely affect the EMG-force relation.

  14. EMG of the hip adductor muscles in six clinical examination tests.

    Science.gov (United States)

    Lovell, Gregory A; Blanch, Peter D; Barnes, Christopher J

    2012-08-01

    To assess activation of muscles of hip adduction using EMG and force analysis during standard clinical tests, and compare athletes with and without a prior history of groin pain. Controlled laboratory study. 21 male athletes from an elite junior soccer program. Bilateral surface EMG recordings of the adductor magnus, adductor longus, gracilis and pectineus as well as a unilateral fine-wire EMG of the pectineus were made during isometric holds in six clinical examination tests. A load cell was used to measure force data. Test type was a significant factor in the EMG output for all four muscles (all muscles p EMG activation was highest in Hips 0 or Hips 45 for adductor magnus, adductor longus and gracilis. EMG activation for pectineus was highest in Hips 90. Injury history was a significant factor in the EMG output for the adductor longus (p test type was a significant factor (p EMG output). Muscle EMG varied significantly with clinical test position. Athletes with previous groin injury had a significant fall in some EMG outputs. Copyright © 2011 Elsevier Ltd. All rights reserved.

  15. Spatial variation and inconsistency between estimates of onset of muscle activation from EMG and ultrasound

    Science.gov (United States)

    Dieterich, Angela V.; Botter, Alberto; Vieira, Taian Martins; Peolsson, Anneli; Petzke, Frank; Davey, Paul; Falla, Deborah

    2017-01-01

    Delayed onset of muscle activation can be a descriptor of impaired motor control. Activation onset can be estimated from electromyography (EMG)-registered muscle excitation and from ultrasound-registered muscle motion, which enables non-invasive measurements in deep muscles. However, in voluntary activation, EMG- and ultrasound-detected activation onsets may not correspond. To evaluate this, ten healthy men performed isometric elbow flexion at 20% to 70% of their maximal force. Utilising a multi-channel electrode transparent to ultrasound, EMG and M(otion)-mode ultrasound were recorded simultaneously over the biceps brachii muscle. The time intervals between automated and visually estimated activation onsets were correlated with the regional variation of EMG and muscle motion onset, contraction level and speed. Automated and visual onsets indicated variable time intervals between EMG- and motion onset, median (interquartile range) 96 (121) ms and 48 (72) ms, respectively. In 17% (computed analysis) or 23% (visual analysis) of trials, motion onset was detected before local EMG onset. Multi-channel EMG and M-mode ultrasound revealed regional differences in activation onset, which decreased with higher contraction speed (Spearman ρ ≥ 0.45, P EMG- and ultrasound-detected activation onset. PMID:28176821

  16. EMG-force relations during isometric contractions of the first dorsal interosseous muscle after stroke.

    Science.gov (United States)

    Zhou, Ping; Li, Xiaoyan; Rymer, William Zev

    2013-01-01

    This study examines the electromyogram (EMG)-force relations observed in the first dorsal interosseous (FDI) muscle of hemiparetic stroke survivors. Fourteen stroke subjects were instructed to perform different levels of index finger abduction using their paretic and contralateral hands, respectively. Surface EMG and force signals were recorded from the FDI muscle. The EMG-force relation was constructed using linear regression of the EMG amplitude and force measurements. We found that there were diverse changes in the slope of the EMG-force relations in paretic muscles compared with contralateral muscles, with significant increases and decreases being observed relative to the contralateral side. Regression analysis did not verify strong correlations between the ratio of paretic and contralateral muscle EMG-force slopes and any clinical parameters. These findings suggest that there appear to be different types of processes (eg, motor unit control property changes, muscle fiber atrophy, spinal motoneuron degeneration, muscle fiber reinnervation, etc) at work post stroke that may impact the EMG-force relations and that may be present in varying degree in any given stroke survivor.

  17. EMG threshold determination in eight lower limb muscles during cycling exercise: A pilot study

    OpenAIRE

    Hug, François; Laplaud, David; Lucía Mulas, Alejandro; Grelot, Laurent

    2006-01-01

    The first aim of this study was to verify the occurrence of the EMG threshold (EMG (Th)) in each of eight lower limb muscles (vastus lateralis [VL], vatus medialis [VM], rectus femoris [RF], semimembranosus [SM], biceps femoris [BF], gastrocnemius lateralis [GL] and medialis [GM], and tibialis anterior [TA]) during incremental cycling exercise. The second aim was to investigate the test-retest reproducibility of the EMG (Th) occurrence. Six sedentary male subjects (27 +/- 1 years) performed t...

  18. DEVELOPMENT OF THE EMG OF THE SOLEUS MUSCLE IN THE RAT

    NARCIS (Netherlands)

    WESTERGA, J; GRAMSBERGEN, A

    1994-01-01

    The EMG of the soleus muscle was recorded with bipolar electrodes chronically implanted in rats aged 10-30 days. Changes in the activity pattern were studied in relation to motor development. The firing pattern and shape of motor units were studied at higher resolution. EMG activity was closely

  19. EMG-force relationship during static contraction: effects on sensor placement locations on biceps brachii muscle.

    Science.gov (United States)

    Ahamed, Nizam Uddin; Sundaraj, Kenneth; Alqahtani, Mahdi; Altwijri, Omar; Ali, Md Asraf; Islam, Md Anamul

    2014-01-01

    The relationship between surface electromyography (EMG) and force have been the subject of ongoing investigations and remain a subject of controversy. Even under static conditions, the relationships at different sensor placement locations in the biceps brachii (BB) muscle are complex. The aim of this study was to compare the activity and relationship between surface EMG and static force from the BB muscle in terms of three sensor placement locations. Twenty-one right hand dominant male subjects (age 25.3±1.2 years) participated in the study. Surface EMG signals were detected from the subject's right BB muscle. The muscle activation during force was determined as the root mean square (RMS) electromyographic signal normalized to the peak RMS EMG signal of isometric contraction for 10 s. The statistical analysis included linear regression to examine the relationship between EMG amplitude and force of contraction [40-100% of maximal voluntary contraction (MVC)], repeated measures ANOVA to assess differences among the sensor placement locations, and coefficient of variation (CoV) for muscle activity variation. The results demonstrated that when the sensor was placed on the muscle belly, the linear slope coefficient was significantly greater for EMG versus force testing (r2=0.62, P0.05) and upper part of the muscle belly (r2=0.29, PEMG signal activity on the muscle belly had less variability than the upper and lower parts (8.55% vs. 15.12% and 12.86%, respectively). These findings indicate the importance of applying the surface EMG sensor at the appropriate locations that follow muscle fiber orientation of the BB muscle during static contraction. As a result, EMG signals of three different placements may help to understand the difference in the amplitude of the signals due to placement.

  20. Effectiveness of the Wavelet Transform on the Surface EMG to Understand the Muscle Fatigue During Walk

    Science.gov (United States)

    Hussain, M. S.; Mamun, Md.

    2012-01-01

    Muscle fatigue is the decline in ability of a muscle to create force. Electromyography (EMG) is a medical technique for measuring muscle response to nervous stimulation. During a sustained muscle contraction, the power spectrum of the EMG shifts towards lower frequencies. These effects are due to muscle fatigue. Muscle fatigue is often a result of unhealthy work practice. In this research, the effectiveness of the wavelet transform applied to the surface EMG (SEMG) signal as a means of understanding muscle fatigue during walk is presented. Power spectrum and bispectrum analysis on the EMG signal getting from right rectus femoris muscle is executed utilizing various wavelet functions (WFs). It is possible to recognize muscle fatigue appreciably with the proper choice of the WF. The outcome proves that the most momentous changes in the EMG power spectrum are symbolized by WF Daubechies45. Moreover, this research has compared bispectrum properties to the other WFs. To determine muscle fatigue during gait, Daubechies45 is used in this research to analyze the SEMG signal.

  1. Effect of Selective Muscle Training Using Visual Emg Biofeedback on Infraspinatus and Posterior Deltoid

    Directory of Open Access Journals (Sweden)

    Lim One-bin

    2014-12-01

    Full Text Available We investigated the effects of visual electromyography (EMG biofeedback during side-lying shoulder external rotation exercise on the EMG amplitude for the posterior deltoid, infraspinatus, and infraspinatus/posterior deltoid EMG activity ratio. Thirty-one asymptomatic subjects were included. Subjects performed side-lying shoulder external rotation exercise with and without visual EMG biofeedback. Surface EMG was used to collect data from the posterior deltoid and infraspinatus muscles. The visual EMG biofeedback applied the pre-established threshold to prevent excessive posterior deltoid muscle contraction. A paired t-test was used to determine the significance of the measurements between without vs. with visual EMG biofeedback. Posterior deltoid activity significantly decreased while infraspinatus activity and the infraspinatus/posterior activity ratio significantly increased during side-lying shoulder external rotation exercise with visual EMG biofeedback. This suggests that using visual EMG biofeedback during shoulder external rotation exercise is a clinically effective training method for reducing posterior deltoid activity and increasing infraspinatus activity.

  2. Electromyostimulation and EMG real time device with muscle fatigue estimation

    OpenAIRE

    Yochum, Maxime; Bakir, Toufik; Binczak, Stéphane; Lepers, Romuald

    2012-01-01

    International audience; This study presents a system composed of an electromyostimulation (ES) and an electromyograph (EMG) modules which analyze in real time EMG during ES and proposes a new method based on wavelet decomposition to analyze changes in M wave. It leads to introduce a new muscular fatigue index. Different methods to filter the EMG noise are then compared. The results show that this new index gives reliable and robust results even when noise corrupts significantly the signal.

  3. EMG activity of the muscles of the neck and forelimbs during different forms of locomotion.

    Science.gov (United States)

    Tokuriki, M; Ohtsuki, R; Kai, M; Hiraga, A; Oki, H; Miyahara, Y; Aoki, O

    1999-07-01

    We recorded the electromyographic (EMG) activity of 7 skeletal muscles in the forequarters and 1 in the hindquarters of 6 Thoroughbred horses during overground walking, swimming in a circular pool, and walking and trotting in a water treadmill. Bipolar fine wire electrodes were inserted into the muscles and the EMG signals were recorded using a telemetric system. The splenius exhibited tonic EMG activity during swimming. The brachiocephalicus showed its highest intensity during swimming followed by the walk and trot in the water treadmill and then walking overground. The triceps brachii caput longum had a similar activity pattern to the brachiocephalicus. The brachialis showed only weak EMG activity in all 3 types of locomotion. The extensor digitorum communis had higher intensity of EMG activity in the walk in the water treadmill than in other kinds of locomotion. The flexor digitorum profundus exhibited the most intense EMG activity during swimming. These results indicated that swimming evoked strong EMG activity in the antigravity muscles in spite of reduced gravitational force. Walking in the water treadmill may require more intensified EMG activity of the forelimb than the trot in the same treadmill.

  4. An examination of surface EMG for the assessment of muscle tension dysphonia.

    Science.gov (United States)

    Van Houtte, Evelyne; Claeys, Sofie; D'haeseleer, Evelien; Wuyts, Floris; Van Lierde, Kristiane

    2013-03-01

    Muscle tension dysphonia (MTD) is the pathological condition in which an excessive tension of the (para)laryngeal musculature leads to a disturbed voice. Surface electromyography (sEMG) was used to investigate differences in extralaryngeal muscles' tension in patients with MTD compared with normal speakers. sEMG was examined as a diagnostic tool to differentiate between patients with MTD and controls. Eighteen patients with MTD and 44 normal speakers were included in the study. All subjects were evaluated with videostroboscopy, voice assessment protocol, and sEMG. sEMG was performed on three locations of the anterior neck. Measurements were taken during silence, phonation tasks, and while reading, with comparisons made between both study groups. Patients with MTD did not express higher levels of sEMG during rest, phonation, or reading compared with normal speakers. There were no significant differences in sEMG values between males and females in both study groups. sEMG was not able to detect an increase in muscle tension in patients with MTD. The results of this study do not support the use of sEMG as a diagnostic tool for distinguishing patients with and without MTD. Clinical examination with laryngeal palpation, videostroboscopy, and dysphonia severity index remain the key investigations. Copyright © 2013 The Voice Foundation. Published by Mosby, Inc. All rights reserved.

  5. Factors governing the form of the relation between muscle force and the EMG: a simulation study.

    Science.gov (United States)

    Zhou, Ping; Rymer, William Zev

    2004-11-01

    The dependence of the form of the EMG-force relation on key motoneuron and muscle properties was explored using a simulation approach. Surface EMG signals and isometric forces were simulated using existing motoneuron pool, muscle force, and surface EMG models, based primarily on reported properties of the first dorsal interosseous (FDI) muscle in humans. Our simulation results indicate that the relation between electrical and mechanical properties of the individual motor unit level plays the dominant role in determining the overall EMG amplitude-force relation of the muscle, while the underlying motor unit firing rate strategy appears to be a less important factor. However, different motor unit firing rate strategies result in substantially different relations between counts of the numbers of motoneuron discharges and the isometric force. Our simulation results also show that EMG amplitude (estimated as the average rectified value) increases as a result of synchronous discharges of different motor units within the pool, but the magnitude of this increase is determined primarily by the action potential duration of the synchronized motor units. Furthermore, when the EMG effects are normalized to their maximum levels, motor unit synchrony does not exert significant effects on the form of the EMG-force relation, provided that the synchrony level is held similar at different excitation levels.

  6. Quantitative evaluation of muscle relaxation induced by Kundalini yoga with the help of EMG integrator.

    Science.gov (United States)

    Narayan, R; Kamat, A; Khanolkar, M; Kamat, S; Desai, S R; Dhume, R A

    1990-10-01

    The present work is aimed to quantify the degree of relaxation of muscle under the effects of Kundalini Yoga with the help of EMG integrator. The data collected from 8 individuals (4 males 4 females) on the degree of muscle relaxation at the end of meditation revealed a significantly decreased muscle activity amounting to 58% of the basal level in both the sexes.

  7. Analysis of scapular muscle EMG activity in patients with idiopathic neck pain: a systematic review.

    Science.gov (United States)

    Castelein, Birgit; Cools, Ann; Bostyn, Emma; Delemarre, Jolien; Lemahieu, Trees; Cagnie, Barbara

    2015-04-01

    It is proposed that altered scapular muscle function can contribute to abnormal loading of the cervical spine. However, it is not clear if patients with idiopathic neck pain show altered activity of the scapular muscles. The aim of this paper was to systematically review the literature regarding the differences or similarities in scapular muscle activity, measured by electromyography ( = EMG), between patients with chronic idiopathic neck pain compared to pain-free controls. Case-control (neck pain/healthy) studies investigating scapular muscle EMG activity (amplitude, timing and fatigue parameters) were searched in Pubmed and Web of Science. 25 articles were included in the systematic review. During rest and activities below shoulder height, no clear differences in mean Upper Trapezius ( = UT) EMG activity exist between patients with idiopathic neck pain and a healthy control group. During overhead activities, no conclusion for scapular EMG amplitude can be drawn as a large variation of results were reported. Adaptation strategies during overhead tasks are not the same between studies. Only one study investigated timing of the scapular muscles and found a delayed onset and shorter duration of the SA during elevation in patients with idiopathic neck pain. For scapular muscle fatigue, no definite conclusions can be made as a wide variation and conflicting results are reported. Further high quality EMG research on scapular muscles (broader than the UT) is necessary to understand/draw conclusions on how scapular muscles react in the presence of idiopathic neck pain. Copyright © 2015 Elsevier Ltd. All rights reserved.

  8. Muscle fatigue evaluation of astronaut upper limb based on sEMG and subjective assessment

    Science.gov (United States)

    Zu, Xiaoqi; Zhou, Qianxiang; Li, Yun

    2012-07-01

    All movements are driven by muscle contraction, and it is easy to cause muscle fatigue. Evaluation of muscle fatigue is a hot topic in the area of astronaut life support training and rehabilitation. If muscle gets into fatigue condition, it may reduce work efficiency and has an impact on psychological performance. Therefore it is necessary to develop an accurate and usable method on muscle fatigue evaluation of astronaut upper limb. In this study, we developed a method based on surface electromyography (sEMG) and subjective assessment (Borg scale) to evaluate local muscle fatigue. Fifteen healthy young male subjects participated in the experiment. They performed isometric muscle contractions of the upper limb. sEMG of the biceps brachii were recorded during the entire process of isotonic muscle contraction and Borg scales of muscle fatigue were collected in certain times. sEMG were divided into several parts, and then mean energy of each parts were calculated by the one-twelfth band octave method. Equations were derived based on the relationship between the mean energy of sEMG and Borg scale. The results showed that cubic curve could describe the degree of local muscle fatigue, and could be used to evaluate and monitor local muscle fatigue during the entire process.

  9. An Analysis of Intrinsic and Extrinsic Hand Muscle EMG for Improved Pattern Recognition Control

    Science.gov (United States)

    Adewuyi, Adenike A.; Hargrove, Levi J.; Kuiken, Todd A.

    2015-01-01

    Pattern recognition control combined with surface electromyography (EMG) from the extrinsic hand muscles has shown great promise for control of multiple prosthetic functions for transradial amputees. There is, however, a need to adapt this control method when implemented for partial-hand amputees, who possess both a functional wrist and information-rich residual intrinsic hand muscles. We demonstrate that combining EMG data from both intrinsic and extrinsic hand muscles to classify hand grasps and finger motions allows up to 19 classes of hand grasps and individual finger motions to be decoded, with an accuracy of 96% for non-amputees and 85% for partial-hand amputees. We evaluated real-time pattern recognition control of three hand motions in seven different wrist positions. We found that a system trained with both intrinsic and extrinsic muscle EMG data, collected while statically and dynamically varying wrist position increased completion rates from 73% to 96% for partial-hand amputees and from 88% to 100% for non-amputees when compared to a system trained with only extrinsic muscle EMG data collected in a neutral wrist position. Our study shows that incorporating intrinsic muscle EMG data and wrist motion can significantly improve the robustness of pattern recognition control for partial-hand applications. PMID:25955989

  10. Evaluation of methods for extraction of the volitional EMG in dynamic hybrid muscle activation

    Directory of Open Access Journals (Sweden)

    Mizrahi Joseph

    2006-11-01

    Full Text Available Abstract Background Hybrid muscle activation is a modality used for muscle force enhancement, in which muscle contraction is generated from two different excitation sources: volitional and external, by means of electrical stimulation (ES. Under hybrid activation, the overall EMG signal is the combination of the volitional and ES-induced components. In this study, we developed a computational scheme to extract the volitional EMG envelope from the overall dynamic EMG signal, to serve as an input signal for control purposes, and for evaluation of muscle forces. Methods A "synthetic" database was created from in-vivo experiments on the Tibialis Anterior of the right foot to emulate hybrid EMG signals, including the volitional and induced components. The database was used to evaluate the results obtained from six signal processing schemes, including seven different modules for filtration, rectification and ES component removal. The schemes differed from each other by their module combinations, as follows: blocking window only, comb filter only, blocking window and comb filter, blocking window and peak envelope, comb filter and peak envelope and, finally, blocking window, comb filter and peak envelope. Results and conclusion The results showed that the scheme including all the modules led to an excellent approximation of the volitional EMG envelope, as extracted from the hybrid signal, and underlined the importance of the artifact blocking window module in the process. The results of this work have direct implications on the development of hybrid muscle activation rehabilitation systems for the enhancement of weakened muscles.

  11. To What Extent Is Mean EMG Frequency during Gait a Reflection of Functional Muscle Strength in Children with Cerebral Palsy?

    Science.gov (United States)

    Van Gestel, L.; Wambacq, H.; Aertbelien, E.; Meyns, P.; Bruyninckx, H.; Bar-On, L.; Molenaers, G.; De Cock, P.; Desloovere, K.

    2012-01-01

    The aim of the current paper was to analyze the potential of the mean EMG frequency, recorded during 3D gait analysis (3DGA), for the evaluation of functional muscle strength in children with cerebral palsy (CP). As walking velocity is known to also influence EMG frequency, it was investigated to which extent the mean EMG frequency is a reflection…

  12. Back muscle EMG of helicopter pilots in flight: effects of fatigue, vibration, and posture.

    Science.gov (United States)

    de Oliveira, Carlos Gomes; Nadal, Jurandir

    2004-04-01

    The high prevalence of low back pain in helicopter pilots has been attributed to back muscle fatigue due to a pilot's required posture and/or aircraft vibration. This study investigated the effect of posture and vibration on the surface electromyogram (EMG) of right and left erector spinae (ES) muscles of pilots and evaluated ES fatigue during flight. There were 12 male pilots who were monitored during helicopter flights lasting an average of 2 h. Prior to the flight, a maximal voluntary contraction (MVC) of ES was performed and the EMG was recorded. Vibration was measured at the pilot's seat through a triaxial accelerometer. The effect of posture on EMG was tested by comparing four characteristics of left and right EMG expressed as % MVC. Effect of Z vibration on EMG was investigated by coherence function and through correlation between coherently averaged EMG and Z for the frequencies of the main rotor of the helicopter (1R) and its first harmonic (2R). Fatigue was investigated through median frequencies (MF) of the EMG power spectra. No effect of posture on EMG was found for any parameter (p > 0.05). Data from one pilot suggested an effect of 1R on EMG, but statistical tests revealed this not to be significant (p > 0.05) for any pilot. No fatigue was evidenced by linear regression of MF. While the scientific literature contains the hypothesis that low back pain in helicopter pilots is mainly due to muscle fatigue caused by posture and/or vibration, the present study did not lend support to this hypothesis.

  13. EMG parameters and EEG α Index change at fatigue period during different types of muscle contraction

    Science.gov (United States)

    Zhang, Li; Zhou, Bin; Song, Gaoqing

    2011-03-01

    The purpose of this study is to measure and analyze the characteristics in change of EMG and EEG parameters at muscle fatigue period in participants with different exercise capacity. Twenty participants took part in the tests. They were divided into two groups, Group A (constant exerciser) and Group B (seldom-exerciser). MVC dynamic and 1/3 isometric exercises were performed; EMG and EEG signals were recorded synchronously during different type of muscle contraction. Results indicated that values of MVC, RMS and IEMG in Group A were greater than Group B, but isometric exercise time was shorter than the time of dynamic exercise although its intensity was light. Turning point of IEMG and α Index occurred synchronously during constant muscle contraction of isometric or dynamic exercise. It is concluded that IEMG turning point may be an indication to justify muscle fatigue. Synchronization of EEG and EMG reflects its common characteristics on its bio-electric change.

  14. Analysis of sEMG signals using discrete wavelet transform for muscle fatigue detection

    Science.gov (United States)

    Flórez-Prias, L. A.; Contreras-Ortiz, S. H.

    2017-11-01

    The purpose of the present article is to characterize sEMG signals to determine muscular fatigue levels. To do this, the signal is decomposed using the discrete wavelet transform, which offers noise filtering features, simplicity and efficiency. sEMG signals on the forearm were acquired and analyzed during the execution of cyclic muscular contractions in the presence and absence of fatigue. When the muscle fatigues, the sEMG signal shows a more erratic behavior of the signal as more energy is required to maintain the effort levels.

  15. Convolutive blind source separation of surface EMG measurements of the respiratory muscles.

    Science.gov (United States)

    Petersen, Eike; Buchner, Herbert; Eger, Marcus; Rostalski, Philipp

    2017-04-01

    Electromyography (EMG) has long been used for the assessment of muscle function and activity and has recently been applied to the control of medical ventilation. For this application, the EMG signal is usually recorded invasively by means of electrodes on a nasogastric tube which is placed inside the esophagus in order to minimize noise and crosstalk from other muscles. Replacing these invasive measurements with an EMG signal obtained non-invasively on the body surface is difficult and requires techniques for signal separation in order to reconstruct the contributions of the individual respiratory muscles. In the case of muscles with small cross-sectional areas, or with muscles at large distances from the recording site, solutions to this problem have been proposed previously. The respiratory muscles, however, are large and distributed widely over the upper body volume. In this article, we describe an algorithm for convolutive blind source separation (BSS) that performs well even for large, distributed muscles such as the respiratory muscles, while using only a small number of electrodes. The algorithm is derived as a special case of the TRINICON general framework for BSS. To provide evidence that it shows potential for separating inspiratory, expiratory, and cardiac activities in practical applications, a joint numerical simulation of EMG and ECG activities was performed, and separation success was evaluated in a variety of noise settings. The results are promising.

  16. Masticatory Muscle Sleep Background EMG Activity is Elevated in Myofascial TMD Patients

    Science.gov (United States)

    Raphael, Karen G.; Janal, Malvin N.; Sirois, David A.; Dubrovsky, Boris; Wigren, Pia E.; Klausner, Jack J.; Krieger, Ana C.; Lavigne, Gilles J.

    2013-01-01

    Despite theoretical speculation and strong clinical belief, recent research using laboratory polysomnographic (PSG) recording has provided new evidence that frequency of sleep bruxism (SB) masseter muscle events, including grinding or clenching of the teeth during sleep, is not increased for women with chronic myofascial temporomandibular disorder (TMD). The current case-control study compares a large sample of women suffering from chronic myofascial TMD (n=124) with a demographically matched control group without TMD (n=46) on sleep background electromyography (EMG) during a laboratory PSG study. Background EMG activity was measured as EMG root mean square (RMS) from the right masseter muscle after lights out. Sleep background EMG activity was defined as EMG RMS remaining after activity attributable to SB, other orofacial activity, other oromotor activity and movement artifacts were removed. Results indicated that median background EMG during these non SB-event periods was significantly higher (pmyofascial TMD (median=3.31 μV and mean=4.98 μV) than for control women (median=2.83 μV and mean=3.88 μV) with median activity in 72% of cases exceeding control activity. Moreover, for TMD cases, background EMG was positively associated and SB event-related EMG was negatively associated with pain intensity ratings (0–10 numerical scale) on post sleep waking. These data provide the foundation for a new focus on small, but persistent, elevations in sleep EMG activity over the course of the night as a mechanism of pain induction or maintenance. PMID:24237356

  17. Mechanically corrected EMG for the continuous estimation of erector spinae muscle loading during repetitive lifting.

    Science.gov (United States)

    Potvin, J R; Norman, R W; McGill, S M

    1996-01-01

    Few studies have been carried out on the changes in biomechanical loading on low-back tissues during prolonged lifting. The purpose of this paper was to develop a model for continuously estimating erector spinae muscle loads during repetitive lifting and lowering tasks. The model was based on spine kinematics and bilateral lumbar and thoracic erector spinae electromyogram (EMG) signals and was developed with the data from eight male subjects. Each subject performed a series of isometric contractions to develop extensor moments about the low back. Maximum voluntary contractions (MVCs) were used to normalize all recorded EMG and moment time-histories. Ramp contractions were used to determine the non-linear relationship between extensor moments and EMG amplitudes. In addition, the most appropriate low-pass filter cut-off frequencies were calculated for matching the rectified EMG signals with the moment patterns. The mean low-pass cut-off frequency was 2.7 (0.4) Hz. The accuracy of the non-linear EMG-based estimates of isometric extensor moment were tested with data from a series of six rapid contractions by each subject. The mean error over the duration of these contractions was 9.2 (2.6)% MVC. During prolonged lifting sessions of 20 min and of 2 h, a model was used to calculate changes in muscle length based on monitored spine kinematics. EMG signals were first processed according to the parameters determined from the isometric contractions and then further processed to account for the effects of instantaneous muscle length and velocity. Simple EMG estimates were found to underestimate peak loading by 9.1 (4.0) and 25.7 (11.6)% MVC for eccentric and concentric phases of lifting respectively, when compared to load estimates based on the mechanically corrected EMG. To date, the model has been used to analyze over 5300 lifts.

  18. The classification for "equilibrium triad" sensory loss based on sEMG signals of calf muscles.

    Science.gov (United States)

    Hairong Yu; Kairui Guo; Jie Luo; Kai Cao; Nguyen, Hung T; Su, Steven W

    2017-07-01

    Surface Electromyography (sEMG) has been commonly applied for analysing the electrical activities of skeletal muscles. The sensory system of maintaining posture balance includes vision, proprioception and vestibular senses. In this work, an attempt is made to classify whether the body is missing one of the sense during balance control by using sEMG signals. A trial of combination with different features and muscles is also developed. The results demonstrate that the classification accuracy between vision loss and the normal condition is higher than the one between vestibular sense loss and normal condition. When using different features and muscles, the impact on classification results is also different. The outcomes of this study could aid the development of sEMG based classification for the function of sensory systems during human balance movement.

  19. Compression of high-density EMG signals for trapezius and gastrocnemius muscles

    Science.gov (United States)

    2014-01-01

    Background New technologies for data transmission and multi-electrode arrays increased the demand for compressing high-density electromyography (HD EMG) signals. This article aims the compression of HD EMG signals recorded by two-dimensional electrode matrices at different muscle-contraction forces. It also shows methodological aspects of compressing HD EMG signals for non-pinnate (upper trapezius) and pinnate (medial gastrocnemius) muscles, using image compression techniques. Methods HD EMG signals were placed in image rows, according to two distinct electrode orders: parallel and perpendicular to the muscle longitudinal axis. For the lossless case, the images obtained from single-differential signals as well as their differences in time were compressed. For the lossy algorithm, the images associated to the recorded monopolar or single-differential signals were compressed for different compression levels. Results Lossless compression provided up to 59.3% file-size reduction (FSR), with lower contraction forces associated to higher FSR. For lossy compression, a 90.8% reduction on the file size was attained, while keeping the signal-to-noise ratio (SNR) at 21.19 dB. For a similar FSR, higher contraction forces corresponded to higher SNR Conclusions The computation of signal differences in time improves the performance of lossless compression while the selection of signals in the transversal order improves the lossy compression of HD EMG, for both pinnate and non-pinnate muscles. PMID:24612604

  20. Functional mapping of the pelvic floor and sphincter muscles from high-density surface EMG recordings.

    Science.gov (United States)

    Peng, Yun; He, Jinbao; Khavari, Rose; Boone, Timothy B; Zhang, Yingchun

    2016-11-01

    Knowledge of the innervation of pelvic floor and sphincter muscles is of great importance to understanding the pathophysiology of female pelvic floor dysfunctions. This report presents our high-density intravaginal and intrarectal electromyography (EMG) probes and a comprehensive innervation zone (IZ) imaging technique based on high-density EMG readings to characterize the IZ distribution. Both intravaginal and intrarectal probes are covered with a high-density surface electromyography electrode grid (8 × 8). Surface EMG signals were acquired in ten healthy women performing maximum voluntary contractions of their pelvic floor. EMG decomposition was performed to separate motor-unit action potentials (MUAPs) and then localize their IZs. High-density surface EMG signals were successfully acquired over the vaginal and rectal surfaces. The propagation patterns of muscle activity were clearly visualized for multiple muscle groups of the pelvic floor and anal sphincter. During each contraction, up to 218 and 456 repetitions of motor units were detected by the vaginal and rectal probes, respectively. MUAPs were separated with their IZs identified at various orientations and depths. The proposed probes are capable of providing a comprehensive mapping of IZs of the pelvic floor and sphincter muscles. They can be employed as diagnostic and preventative tools in clinical practices.

  1. Assessment of the paraspinal muscles of subjects presenting an idiopathic scoliosis: an EMG pilot study

    Directory of Open Access Journals (Sweden)

    Larivière Christian

    2005-03-01

    Full Text Available Abstract Background It is known that the back muscles of scoliotic subjects present abnormalities in their fiber type composition. Some researchers have hypothesized that abnormal fiber composition can lead to paraspinal muscle dysfunction such as poor neuromuscular efficiency and muscle fatigue. EMG parameters were used to evaluate these impairments. The purpose of the present study was to examine the clinical potential of different EMG parameters such as amplitude (RMS and median frequency (MF of the power spectrum in order to assess the back muscles of patients presenting idiopathic scoliosis in terms of their neuromuscular efficiency and their muscular fatigue. Methods L5/S1 moments during isometric efforts in extension were measured in six subjects with idiopathic scoliosis and ten healthy controls. The subjects performed three 7 s ramp contractions ranging from 0 to 100% maximum voluntary contraction (MVC and one 30 s sustained contraction at 75% MVC. Surface EMG activity was recorded bilaterally from the paraspinal muscles at L5, L3, L1 and T10. The slope of the EMG RMS/force (neuromuscular efficiency and MF/force (muscle composition relationships were computed during the ramp contractions while the slope of the EMG RMS/time and MF/time relationships (muscle fatigue were computed during the sustained contraction. Comparisons were performed between the two groups and between the left and right sides for the EMG parameters. Results No significant group or side differences between the slopes of the different measures used were found at the level of the apex (around T10 of the major curve of the spine. However, a significant side difference was seen at a lower level (L3, p = 0.01 for the MF/time parameter. Conclusion The EMG parameters used in this study could not discriminate between the back muscles of scoliotic subjects and those of control subject regarding fiber type composition, neuromuscular efficiency and muscle fatigue at the level

  2. Evoked EMG-based torque prediction under muscle fatigue in implanted neural stimulation

    Science.gov (United States)

    Hayashibe, Mitsuhiro; Zhang, Qin; Guiraud, David; Fattal, Charles

    2011-10-01

    In patients with complete spinal cord injury, fatigue occurs rapidly and there is no proprioceptive feedback regarding the current muscle condition. Therefore, it is essential to monitor the muscle state and assess the expected muscle response to improve the current FES system toward adaptive force/torque control in the presence of muscle fatigue. Our team implanted neural and epimysial electrodes in a complete paraplegic patient in 1999. We carried out a case study, in the specific case of implanted stimulation, in order to verify the corresponding torque prediction based on stimulus evoked EMG (eEMG) when muscle fatigue is occurring during electrical stimulation. Indeed, in implanted stimulation, the relationship between stimulation parameters and output torques is more stable than external stimulation in which the electrode location strongly affects the quality of the recruitment. Thus, the assumption that changes in the stimulation-torque relationship would be mainly due to muscle fatigue can be made reasonably. The eEMG was proved to be correlated to the generated torque during the continuous stimulation while the frequency of eEMG also decreased during fatigue. The median frequency showed a similar variation trend to the mean absolute value of eEMG. Torque prediction during fatigue-inducing tests was performed based on eEMG in model cross-validation where the model was identified using recruitment test data. The torque prediction, apart from the potentiation period, showed acceptable tracking performances that would enable us to perform adaptive closed-loop control through implanted neural stimulation in the future.

  3. [Hardware and software for EMG recording and analysis of respiratory muscles of human].

    Science.gov (United States)

    Solnushkin, S D; Chakhman, V N; Segizbaeva, M O; Pogodin, M A; Aleksandrov, V G

    2014-01-01

    This paper presents a new hardware and software system that allows to not only record the EMG of different groups of the respiratory muscles, but also hold its amplitude-frequency analysis, which allows to determine the change in the contribution to the work of breathing of a respiratory muscles and detect early signs of fatigue of the respiratory muscles. Presented complex can be used for functional diagnostics of breath in patients and healthy people and sportsmen.

  4. Force production and EMG activity of neck muscles in adolescent headache.

    Science.gov (United States)

    Oksanen, Airi; Pöyhönen, Tapani; Ylinen, Jari J; Metsähonkala, Liisa; Anttila, Pirjo; Laimi, Katri; Hiekkanen, Heikki; Aromaa, Minna; Salminen, Jouko J; Sillanpää, Matti

    2008-01-01

    This study compared the maximal force, EMG/force ratio and co-activation characteristics of the neck-shoulder muscles between 30 adolescents with migraine-type headache, 29 with tension-type headache, and 30 headache-free controls. Force was measured with surface electromyography (EMG) from the cervical erector spinae (CES), the sternocleidomastoid (SCM) and trapezius muscles during the maximal isometric neck flexion, neck extension and shoulder flexion. Girls with migraine-type headache had higher EMG/force ratios between the EMG of the left agonist SCM muscle and the corresponding maximal neck flexion (p = 0.030) and neck rotation force to the right side (p = 0.024) than the girls with tension-type headache. Migrainous girls had more co-activation of right antagonist CES muscle during maximal neck flexion force than the girls without headache (p = 0.015). Neck force production showed no significant differences between girls. Girls with tension-type headache displayed lower left shoulder flexion force than girls with migraine-type headache (p = 0.005) or with no headache (p = 0.005). In boys, no significant differences were observed. Girls with tension-type headache and migraine-type headache have differences in neuromuscular function in the neck-shoulder muscles. The data amplify our knowledge of the neck-shoulder muscle dysfunction in adolescent headache, and may encourage the use of specific rehabilitation methods in the management of different types of headache.

  5. Torque-EMG-velocity relationship in female workers with chronic neck muscle pain

    DEFF Research Database (Denmark)

    Andersen, Lars L; Nielsen, Pernille K; Søgaard, Karen

    2008-01-01

    registered before and after the dynamometer test. The main findings were that shoulder abduction torque (at -60 and 60 degrees s(-1)) and trapezius EMG amplitude (at -60, 0 and 60 degrees s(-1)) were significantly lower in MYA compared with CON (pmuscle thickness...... trapezius muscle. The most consistent differences-in terms of both torque and EMG-were found during slow concentric and eccentric contractions. Activity of the synergistic pain free deltoideus muscle was not significantly lower, indicating specific inhibitory feedback of the painful trapezius muscle only......The present study investigated the effect of chronic neck muscle pain (defined as trapezius myalgia) on neck/shoulder muscle function during concentric, eccentric and static contraction. Forty-two female office workers with trapezius myalgia (MYA) and 20 healthy matched controls (CON) participated...

  6. Determination of an Optimal Threshold Value for Muscle Activity Detection in EMG Analysis

    Science.gov (United States)

    Özgünen, Kerem Tuncay; Çelik, Umut; Kurdak, Sanlı Sadi

    2010-01-01

    It is commonly agreed that one needs to use a threshold value in the detection of muscle activity timing in electromyographic (EMG) signal analysis. However, the algorithm for threshold determination lacks an agreement between the investigators. In this study we aimed to determine a proper threshold value in an incremental cycling exercise for accurate EMG signal analysis. Nine healthy recreationally active male subjects cycled until exhaustion. EMG recordings were performed on four low extremity muscle groups; gastrocnemius lateralis (GL), gastrocnemius medialis (GM), soleus (SOL) and vastus medialis (VM). We have analyzed our data using three different threshold levels: 25%, 35% and 45% of the mean RMS EMG value. We compared the appropriateness of these threshold values using two criteria: (1) significant correlation between the actual and estimated number of bursts and (2) proximity of the regression line of the actual and estimated number of bursts to the line of identity. It had been possible to find a significant correlation between the actual and estimated number of bursts with the 25, 35 and 45% threshold values for the GL muscle. Correlation analyses for the VM muscle had shown that the number of bursts estimated with the 35% threshold value was found to be significantly correlated with the actual number of bursts. For the GM muscle, it had been possible to predict the burst number by using either the 35% or 45% threshold value and for the SOL muscle the 25% threshold value was found as the best predictor for actual number of burst estimation. Detailed analyses of the actual and estimated number of bursts had shown that success of threshold estimation may differ among muscle groups. Evaluation of our data had clearly shown that it is important to select proper threshold values for correct EMG signal analyses. Using a single threshold value for different exercise intensities and different muscle groups may cause misleading results. Key points α priori

  7. Comparison of EMG during passive stretching and shortening phases of each muscle for the investigation of parkinsonian rigidity.

    Science.gov (United States)

    Kwon, Yuri; Kim, Ji-Won; Kim, Ji-Sun; Koh, Seong-Beom; Eom, Gwang-Moon; Lim, Tae-Hong

    2015-01-01

    The aim of this study was to test the hypothesis in the literature that torque resistance of parkinsonian rigidity is the difference between the independent contributions of stretched and shortened muscles. The hypothesis was tested using muscle-specific stretch-shortening (MSSS) EMG ratio in this study. Nineteen patients with idiopathic Parkinson's disease (PD) and 18 healthy subjects (the mean age comparable to that of patients) participated in this study. The EMG activity was measured in the four muscles involved in wrist joint movement, i.e. flexor carpi radialis, flexor carpi ulnaris, extensor carpi radialis and extensor carpi ulnaris. The passive flexion-extension movement with a range of ±30∘ was applied at wrist joint. Root mean squared (RMS) mean was calculated from the envelope of the EMG for each of stretching and shortening phases. MSSS EMG ratio was defined as the ratio of RMS EMG of stretching phase and RMS EMG of shortening phase of a single muscle, and it was calculated for each muscle. MSSS EMG ratios were smaller than one in all muscles. These results indicate that all wrist muscles generate greater mean EMG during shortening than during stretching. Therefore, the torque resistance of parkinsonian rigidity cannot be explained as the simple summation of independent antagonistic torque pair.

  8. High-density surface EMG maps from upper-arm and forearm muscles

    Directory of Open Access Journals (Sweden)

    Rojas-Martínez Monica

    2012-12-01

    Full Text Available Abstract Background sEMG signal has been widely used in different applications in kinesiology and rehabilitation as well as in the control of human-machine interfaces. In general, the signals are recorded with bipolar electrodes located in different muscles. However, such configuration may disregard some aspects of the spatial distribution of the potentials like location of innervation zones and the manifestation of inhomogineties in the control of the muscular fibers. On the other hand, the spatial distribution of motor unit action potentials has recently been assessed with activation maps obtained from High Density EMG signals (HD-EMG, these lasts recorded with arrays of closely spaced electrodes. The main objective of this work is to analyze patterns in the activation maps, associating them with four movement directions at the elbow joint and with different strengths of those tasks. Although the activation pattern can be assessed with bipolar electrodes, HD-EMG maps could enable the extraction of features that depend on the spatial distribution of the potentials and on the load-sharing between muscles, in order to have a better differentiation between tasks and effort levels. Methods An experimental protocol consisting of isometric contractions at three levels of effort during flexion, extension, supination and pronation at the elbow joint was designed and HD-EMG signals were recorded with 2D electrode arrays on different upper-limb muscles. Techniques for the identification and interpolation of artifacts are explained, as well as a method for the segmentation of the activation areas. In addition, variables related to the intensity and spatial distribution of the maps were obtained, as well as variables associated to signal power of traditional single bipolar recordings. Finally, statistical tests were applied in order to assess differences between information extracted from single bipolar signals or from HD-EMG maps and to analyze

  9. Supralaryngeal muscle activity during sustained vibrato in four sopranos: surface EMG findings.

    Science.gov (United States)

    Sapir, S; Larson, K K

    1993-09-01

    Four classically trained sopranos, aged 22-41 years, sustained a vibrato at a comfortable loudness level, and at different vowels (/u/, /i/, or /a/) and pitch levels (220, 277, 349, 440, 554, 698, or 880 Hz). Pairs of surface electrodes were placed on each singer's right side over the submandibular region, the thyroid cartilage, mandibular ramus, and upper lip to record electromyographic (EMG) activity from the anterior suprahyoid (ASH), extralaryngeal (ELAR), massetter (MAS), and perioral (PER) muscles, respectively. A headset-mounted miniature microphone transduced the voice, and a Kay Visi-Pitch extracted the voice fundamental frequency (F0). The output of the Visi-Pitch, a voltage analog of the F0 (VF0), and the EMG signals were digitized, the EMG signals rectified and smoothed, and the VF0 and smoothed EMG signals were subjected to Fast Fourier Transform (FFT) analysis. Spectral peaks in the FFT records indicated vibrato-related activity in the ASH and ELAR muscles, with occasional vibrato-related activity in the MAS and PER muscles. The role of supralaryngeal muscles in vibrato is discussed.

  10. Calibration of EMG to force for knee muscles is applicable with submaximal voluntary contractions

    NARCIS (Netherlands)

    Doorenbosch, C.A.M.; Joosten, A.; Harlaar, J.

    2005-01-01

    Purpose: In this study, the influence of using submaximal isokinetic contractions about the knee compared to maximal voluntary contractions as input to obtain the calibration of an EMG-force model for knee muscles is investigated. Methods: Isokinetic knee flexion and extension contractions were

  11. Knee joint angle affects EMG-force relationship in the vastus intermedius muscle.

    Science.gov (United States)

    Saito, Akira; Akima, Hiroshi

    2013-12-01

    It is not understood how the knee joint angle affects the relationship between electromyography (EMG) and force of four individual quadriceps femoris (QF) muscles. The purpose of this study was to examine the effect of the knee joint angle on the EMG-force relationship of the four individual QF muscles, particularly the vastus intermedius (VI), during isometric knee extensions. Eleven healthy men performed 20-100% of maximal voluntary contraction (MVC) at knee joint angles of 90°, 120° and 150°. Surface EMG of the four QF synergists was recorded and normalized by the root mean square during MVC. The normalized EMG of the four QF synergists at a knee joint angle of 150° was significantly lower than that at 90° and 120° (P knee joint angle of 150°. Furthermore, the neuromuscular activation of the VI was the most sensitive to change in muscle length among the four QF synergistic muscles. Copyright © 2013 Elsevier Ltd. All rights reserved.

  12. Control of Leg Movements Driven by EMG Activity of Shoulder Muscles

    OpenAIRE

    La Scaleia, Valentina; Sylos-Labini, Francesca; Hoellinger, Thomas; Wang, Letian; Cheron, Guy; Lacquaniti, Francesco; Ivanenko, Yuri P.

    2014-01-01

    During human walking, there exists a functional neural coupling between arms and legs, and between cervical and lumbosacral pattern generators. Here, we present a novel approach for associating the electromyographic (EMG) activity from upper limb muscles with leg kinematics. Our methodology takes advantage of the high involvement of shoulder muscles in most locomotor-related movements and of the natural co-ordination between arms and legs. Nine healthy subjects were asked to walk at different...

  13. Torque-EMG-velocity relationship in female workers with chronic neck muscle pain.

    Science.gov (United States)

    Andersen, Lars L; Nielsen, Pernille K; Søgaard, Karen; Andersen, Christoffer H; Skotte, Jørgen; Sjøgaard, Gisela

    2008-01-01

    The present study investigated the effect of chronic neck muscle pain (defined as trapezius myalgia) on neck/shoulder muscle function during concentric, eccentric and static contraction. Forty-two female office workers with trapezius myalgia (MYA) and 20 healthy matched controls (CON) participated. Isokinetic (-60, 60 and 180 degrees s(-1)) and static maximal voluntary shoulder abductions were performed in a Biodex dynamometer, and electromyography (EMG) obtained in the trapezius and deltoideus muscles. Muscle thickness in the trapezius was measured with ultrasound. Pain and perceived exertion were registered before and after the dynamometer test. The main findings were that shoulder abduction torque (at -60 and 60 degrees s(-1)) and trapezius EMG amplitude (at -60, 0 and 60 degrees s(-1)) were significantly lower in MYA compared with CON (p<0.001-0.05). Deltoideus EMG and trapezius muscle thickness were not significantly different between the groups. While perceived exertion increased in both groups in response to the test (p<0.0001), pain increased in MYA only (p<0.0001). In conclusion, having trapezius myalgia was associated with decreased strength capacity and lowered activity of the painful trapezius muscle. The most consistent differences-in terms of both torque and EMG-were found during slow concentric and eccentric contractions. Activity of the synergistic pain free deltoideus muscle was not significantly lower, indicating specific inhibitory feedback of the painful trapezius muscle only. Parallel increase in pain and perceived exertion among MYA were observed in response to the maximal contractions, emphasizing that heavy physical exertion provokes pain increase only in conditions of myalgia.

  14. Age Related Differences in the Surface EMG Signals on Adolescent's Muscle during Contraction

    Science.gov (United States)

    Uddin Ahamed, Nizam; Taha, Zahari; Alqahtani, Mahdi; Altwijri, Omar; Rahman, Matiur; Deboucha, Abdelhakim

    2016-02-01

    The aim of this study was to investigate whether there are differences in the amplitude of the EMG signal among five different age groups of adolescent's muscle. Fifteen healthy adolescents participated in this study and they were divided into five age groups (13, 14, 15, 16 and 17 years). Subjects were performed dynamic contraction during lifting a standard weight (3-kg dumbbell) and EMG signals were recorded from their Biceps Brachii (BB) muscle. Two common EMG analysis techniques namely root mean square (RMS) and mean absolute values (MAV) were used to find the differences. The statistical analysis was included: linear regression to examine the relationships between EMG amplitude and age, repeated measures ANOVA to assess differences among the variables, and finally Coefficient of Variation (CoV) for signal steadiness among the groups of subjects during contraction. The result from RMS and MAV analysis shows that the 17-years age groups exhibited higher activity (0.28 and 0.19 mV respectively) compare to other groups (13-Years: 0.26 and 0.17 mV, 14-years: 0.25 and 0.23 mV, 15-Years: 0.23 and 0.16 mV, 16-years: 0.23 and 0.16 mV respectively). Also, this study shows modest correlation between age and signal activities among all age group's muscle. The experiential results can play a pivotal role for developing EMG prosthetic hand controller, neuromuscular system, EMG based rehabilitation aid and movement biomechanics, which may help to separate age groups among the adolescents.

  15. Effects of EMG processing on biomechanical models of muscle joint systems: sensitivity of trunk muscle moments, spinal forces, and stability.

    NARCIS (Netherlands)

    Staudenmann, D.; Potvin, J.R.; Kingma, I.; Stegeman, D.F.; Dieen, J.H. van

    2007-01-01

    Biomechanical models are in use to estimate parameters such as contact forces and stability at various joints. In one class of these models, surface electromyography (EMG) is used to address the problem of mechanical indeterminacy such that individual muscle activation patterns are accounted for.

  16. EMG (Electromyography) (For Parents)

    Science.gov (United States)

    ... Late for the Flu Vaccine? Eating Disorders Arrhythmias EMG (Electromyogram) KidsHealth > For Parents > EMG (Electromyogram) Print A ... muscular dystrophy and nerve disorders. How Is an EMG Done? Muscles are stimulated by signals from nerve ...

  17. Control of Leg Movements Driven by EMG Activity of Shoulder Muscles.

    Science.gov (United States)

    La Scaleia, Valentina; Sylos-Labini, Francesca; Hoellinger, Thomas; Wang, Letian; Cheron, Guy; Lacquaniti, Francesco; Ivanenko, Yuri P

    2014-01-01

    During human walking, there exists a functional neural coupling between arms and legs, and between cervical and lumbosacral pattern generators. Here, we present a novel approach for associating the electromyographic (EMG) activity from upper limb muscles with leg kinematics. Our methodology takes advantage of the high involvement of shoulder muscles in most locomotor-related movements and of the natural co-ordination between arms and legs. Nine healthy subjects were asked to walk at different constant and variable speeds (3-5 km/h), while EMG activity of shoulder (deltoid) muscles and the kinematics of walking were recorded. To ensure a high level of EMG activity in deltoid, the subjects performed slightly larger arm swinging than they usually do. The temporal structure of the burst-like EMG activity was used to predict the spatiotemporal kinematic pattern of the forthcoming step. A comparison of actual and predicted stride leg kinematics showed a high degree of correspondence (r > 0.9). This algorithm has been also implemented in pilot experiments for controlling avatar walking in a virtual reality setup and an exoskeleton during over-ground stepping. The proposed approach may have important implications for the design of human-machine interfaces and neuroprosthetic technologies such as those of assistive lower limb exoskeletons.

  18. Control of leg movements driven by EMG activity of shoulder muscles

    Directory of Open Access Journals (Sweden)

    Valentina eLa Scaleia

    2014-10-01

    Full Text Available During human walking there exists a functional neural coupling between arms and legs, and between cervical and lumbosacral pattern generators. Here we present a novel approach for associating the electromyographic (EMG activity from upper limb muscles with leg kinematics. Our methodology takes advantage of the high involvement of shoulder muscles in most locomotor-related movements and of the natural coordination between arms and legs. Nine healthy subjects were asked to walk at different constant and variable speeds (3-5 km/h, while EMG activity of shoulder (deltoid muscles and the kinematics of walking were recorded. To ensure a high level of EMG activity in deltoid, the subjects performed slightly larger arm swinging than they usually do. The temporal structure of the burst-like EMG activity was used to predict the spatiotemporal kinematic pattern of the forthcoming step. A comparison of actual and predicted stride leg kinematics showed a high degree of correspondence (r>0.9. This algorithm has been also implemented in pilot experiments for controlling avatar walking in a virtual reality setup and an exoskeleton during overground stepping. The proposed approach may have important implications for the design of human-machine interfaces and neuroprosthetic technologies such as those of assistive lower limb exoskeletons.

  19. Biomathematical pattern of EMG signal propagation in smooth muscle of the non-pregnant porcine uterus.

    Directory of Open Access Journals (Sweden)

    Malgorzata Domino

    Full Text Available Uterine contractions are generated by myometrial smooth muscle cells (SMCs that comprise most of the myometrial layer of the uterine wall. Aberrant uterine motility (i.e., hypo- or hyper-contractility or asynchronous contractions has been implicated in the pathogenesis of infertility due to the failure of implantation, endometriosis and abnormal estrous cycles. The mechanism whereby the non-pregnant uterus initiates spontaneous contractions remains poorly understood. The aim of the present study was to employ linear synchronization measures for analyzing the pattern of EMG signal propagation (direction and speed in smooth muscles of the non-pregnant porcine uterus in vivo using telemetry recording system. It has been revealed that the EMG signal conduction in the uterine wall of the non-pregnant sow does not occur at random but it rather exhibits specific directions and speed. All detectable EMG signals moved along the uterine horn in both cervico-tubal and tubo-cervical directions. The signal migration speed could be divided into the three main types or categories: i. slow basic migration rhythm (SBMR; ii. rapid basic migration rhythm (RBMR; and iii. rapid accessory migration rhythm (RAMR. In conclusion, the EMG signal propagation in smooth muscles of the porcine uterus in vivo can be assessed using a linear synchronization model. Physiological pattern of the uterine contractile activity determined in this study provides a basis for future investigations of normal and pathologicall myogenic function of the uterus.

  20. Control of Leg Movements Driven by EMG Activity of Shoulder Muscles

    Science.gov (United States)

    La Scaleia, Valentina; Sylos-Labini, Francesca; Hoellinger, Thomas; Wang, Letian; Cheron, Guy; Lacquaniti, Francesco; Ivanenko, Yuri P.

    2014-01-01

    During human walking, there exists a functional neural coupling between arms and legs, and between cervical and lumbosacral pattern generators. Here, we present a novel approach for associating the electromyographic (EMG) activity from upper limb muscles with leg kinematics. Our methodology takes advantage of the high involvement of shoulder muscles in most locomotor-related movements and of the natural co-ordination between arms and legs. Nine healthy subjects were asked to walk at different constant and variable speeds (3–5 km/h), while EMG activity of shoulder (deltoid) muscles and the kinematics of walking were recorded. To ensure a high level of EMG activity in deltoid, the subjects performed slightly larger arm swinging than they usually do. The temporal structure of the burst-like EMG activity was used to predict the spatiotemporal kinematic pattern of the forthcoming step. A comparison of actual and predicted stride leg kinematics showed a high degree of correspondence (r > 0.9). This algorithm has been also implemented in pilot experiments for controlling avatar walking in a virtual reality setup and an exoskeleton during over-ground stepping. The proposed approach may have important implications for the design of human–machine interfaces and neuroprosthetic technologies such as those of assistive lower limb exoskeletons. PMID:25368569

  1. Effect of toe extension on EMG of triceps surae muscles during isometric dorsiflexion.

    Science.gov (United States)

    Siddiqi, Ariba; Arjunan, Sridhar P; Kumar, Dinesh

    2016-12-01

    The protocol for estimating force of contraction by triceps surae (TS) muscles requires the immobilization of the ankle during dorsiflexion and plantar flexion. However, large variability in the results has been observed. To identify the cause of this variability, experiments were conducted where ankle dorsiflexion force and electromyogram (EMG) of the TS were recorded under two conditions: (i) toes were strapped and (ii) toes were unstrapped, with all other conditions such as immobilization of the ankle remaining unchanged. The root mean square (RMS) of the EMG and the force were analyzed and one-tail Student's t-test was performed for significance between the two conditions. The RMS of the EMG from TS muscles was found to be significantly higher (~55%) during dorsiflexion with toes unstrapped compared with when the toes were strapped. The torque corresponding to dorsiflexion was also higher with toes unstrapped. Our study has shown that it is important to strap the toes when measuring the torque at the ankle and EMG of the TS muscles.

  2. Biomathematical pattern of EMG signal propagation in smooth muscle of the non-pregnant porcine uterus.

    Science.gov (United States)

    Domino, Malgorzata; Pawlinski, Bartosz; Gajewski, Zdzislaw

    2017-01-01

    Uterine contractions are generated by myometrial smooth muscle cells (SMCs) that comprise most of the myometrial layer of the uterine wall. Aberrant uterine motility (i.e., hypo- or hyper-contractility or asynchronous contractions) has been implicated in the pathogenesis of infertility due to the failure of implantation, endometriosis and abnormal estrous cycles. The mechanism whereby the non-pregnant uterus initiates spontaneous contractions remains poorly understood. The aim of the present study was to employ linear synchronization measures for analyzing the pattern of EMG signal propagation (direction and speed) in smooth muscles of the non-pregnant porcine uterus in vivo using telemetry recording system. It has been revealed that the EMG signal conduction in the uterine wall of the non-pregnant sow does not occur at random but it rather exhibits specific directions and speed. All detectable EMG signals moved along the uterine horn in both cervico-tubal and tubo-cervical directions. The signal migration speed could be divided into the three main types or categories: i. slow basic migration rhythm (SBMR); ii. rapid basic migration rhythm (RBMR); and iii. rapid accessory migration rhythm (RAMR). In conclusion, the EMG signal propagation in smooth muscles of the porcine uterus in vivo can be assessed using a linear synchronization model. Physiological pattern of the uterine contractile activity determined in this study provides a basis for future investigations of normal and pathologicall myogenic function of the uterus.

  3. Contributions to muscle force and EMG by combined neural excitation and electrical stimulation

    Science.gov (United States)

    Crago, Patrick E.; Makowski, Nathaniel S.; Cole, Natalie M.

    2014-10-01

    Objective. Stimulation of muscle for research or clinical interventions is often superimposed on ongoing physiological activity without a quantitative understanding of the impact of the stimulation on the net muscle activity and the physiological response. Experimental studies show that total force during stimulation is less than the sum of the isolated voluntary and stimulated forces, but the occlusion mechanism is not understood. Approach. We develop a model of efferent motor activity elicited by superimposing stimulation during a physiologically activated contraction. The model combines action potential interactions due to collision block, source resetting, and refractory periods with previously published models of physiological motor unit recruitment, rate modulation, force production, and EMG generation in human first dorsal interosseous muscle to investigate the mechanisms and effectiveness of stimulation on the net muscle force and EMG. Main results. Stimulation during a physiological contraction demonstrates partial occlusion of force and the neural component of the EMG, due to action potential interactions in motor units activated by both sources. Depending on neural and stimulation firing rates as well as on force-frequency properties, individual motor unit forces can be greater, smaller, or unchanged by the stimulation. In contrast, voluntary motor unit EMG potentials in simultaneously stimulated motor units show progressive occlusion with increasing stimulus rate. The simulations predict that occlusion would be decreased by a reverse stimulation recruitment order. Significance. The results are consistent with and provide a mechanistic interpretation of previously published experimental evidence of force occlusion. The models also predict two effects that have not been reported previously—voluntary EMG occlusion and the advantages of a proximal stimulation site. This study provides a basis for the rational design of both future experiments and clinical

  4. Low-amplitude craniofacial EMG power spectral density and 3D muscle reconstruction from MRI

    Directory of Open Access Journals (Sweden)

    Lukas Wiedemann

    2015-03-01

    Full Text Available Improving EEG signal interpretation, specificity, and sensitivity is a primary focus of many current investigations, and the successful application of EEG signal processing methods requires a detailed knowledge of both the topography and frequency spectra of low-amplitude, high-frequency craniofacial EMG. This information remains limited in clinical research, and as such, there is no known reliable technique for the removal of these artifacts from EEG data. The results presented herein outline a preliminary investigation of craniofacial EMG high-frequency spectra and 3D MRI segmentation that offers insight into the development of an anatomically-realistic model for characterizing these effects. The data presented highlights the potential for confounding signal contribution from around 60 to 200 Hz, when observed in frequency space, from both low and high-amplitude EMG signals. This range directly overlaps that of both low γ (30-50 Hz and high γ (50-80 Hz waves, as defined traditionally in standatrd EEG measurements, and mainly with waves presented in dense-array EEG recordings. Likewise, average EMG amplitude comparisons from each condition highlights the similarities in signal contribution of low-activity muscular movements and resting, control conditions. In addition to the FFT analysis performed, 3D segmentation and reconstruction of the craniofacial muscles whose EMG signals were measured was successful. This recapitulation of the relevant EMG morphology is a crucial first step in developing an anatomical model for the isolation and removal of confounding low-amplitude craniofacial EMG signals from EEG data. Such a model may be eventually applied in a clinical setting to ultimately help to extend the use of EEG in various clinical roles.

  5. Use of antagonist muscle EMG in the assessment of neuromuscular health of the low back.

    Science.gov (United States)

    Lee, Nakyung; Kang, Hwayeong; Shin, Gwanseob

    2015-04-24

    Non-specific low back pain (LBP) has been one of the most frequently occurring musculoskeletal problems. Impairment in the mechanical stability of the lumbar spine has been known to lower the safety margin of the spine musculature and can result in the occurrence of pain symptoms of the low back area. Previously, changes in spinal stability have been identified by investigating recruitment patterns of low back and abdominal muscles in laboratory experiments with controlled postures and physical activities that were hard to conduct in daily life. The main objective of this study was to explore the possibility of developing a reliable spine stability assessment method using surface electromyography (EMG) of the low back and abdominal muscles in common physical activities. Twenty asymptomatic young participants conducted normal walking, plank, and isometric back extension activities prior to and immediately after maintaining a 10-min static upper body deep flexion on a flat bed. EMG data of the erector spinae, external oblique, and rectus abdominals were collected bilaterally, and their mean normalized amplitude values were compared between before and after the static deep flexion. Changes in the amplitude and co-contraction ratio values were evaluated to understand how muscle recruitment patterns have changed after the static deep flexion. Mean normalized amplitude of antagonist muscles (erector spinae muscles while conducting plank; external oblique and rectus abdominal muscles while conducting isometric back extension) decreased significantly (P muscles did not vary significantly after deep flexion. Results of this study suggest the possibility of using surface EMG in the evaluation of spinal stability and low back health status in simple exercise postures that can be done in non-laboratory settings. Specifically, amplitude of antagonist muscles was found to be more sensitive than agonist muscles in identifying changes in the spinal stability associated with the

  6. Myopathic EMG findings and type II muscle fiber atrophy in patients with Lambert-Eaton myasthenic syndrome

    DEFF Research Database (Denmark)

    Crone, Clarissa; Christiansen, Ingelise; Vissing, John

    2013-01-01

    Lambert-Eaton myasthenic syndrome (LEMS) is a rare condition, which may mimic myopathy. A few reports have described that EMG in LEMS may show changes compatible with myopathy, and muscle biopsies have been described with type II as well as type I atrophy. The EMG results were, however, based...

  7. Rectification of the EMG Signal Impairs the Identification of Oscillatory Input to the Muscle

    OpenAIRE

    Neto, Osmar Pinto; Christou, Evangelos A.

    2009-01-01

    Rectification of EMG signals is a common processing step used when performing electroencephalographic–electromyographic (EEG–EMG) coherence and EMG–EMG coherence. It is well known, however, that EMG rectification alters the power spectrum of the recorded EMG signal (interference EMG). The purpose of this study was to determine whether rectification of the EMG signal influences the capability of capturing the oscillatory input to a single EMG signal and the common oscillations between two EMG ...

  8. Effects of eccentric versus concentric training on thigh muscle strength and EMG.

    Science.gov (United States)

    Seger, J Y; Thorstensson, A

    2005-01-01

    The purpose of this study was to compare pure eccentric and concentric strength training regarding possible specific effects of muscle action type on neuromuscular parameters, such as a decreased inhibition during maximal voluntary eccentric actions. Two groups of young healthy adult men performed 10 weeks of either eccentric or concentric unilateral isokinetic knee extensor training at 90 degrees.s(-1), 4 sets of 10 maximal efforts, 3 days a week. Knee extensor torque and surface EMG from the quadriceps and hamstring muscle groups were collected and quantified in a window between 30 and 70 degrees knee angle (range of motion 90-5 degrees ) during maximal voluntary eccentric and concentric knee extensor actions at 30, 90, and 270 degrees.s(-1). Changes in strength of the trained legs revealed more signs of specificity related to velocity and contraction type after eccentric than concentric training. No major training effects were present in eccentric to concentric ratios of agonist EMG or in relative antagonist (hamstring) activation. Thus, for the trained leg, the muscle action type and speed specific changes in maximal voluntary eccentric strength could not be related to any effects on neural mechanisms, such as a selective increase in muscle activation during eccentric actions. Interestingly, with both types of training there were specific cross-education effects, that is, action type and velocity specific increases in strength occurred in the contralateral, untrained, leg, accompanied by a specific increase in eccentric to concentric EMG ratio after eccentric training.

  9. Reproducibility and responsiveness of a noninvasive EMG technique of the respiratory muscles in COPD patients and in healthy subjects

    NARCIS (Netherlands)

    Duiverman, ML; van Eykern, LA; Vennik, PW; Koeter, GH; Maarsingh, EJW; Wijkstra, PJ

    2004-01-01

    In the present study, we assessed the reproducibility and responsiveness of transcutaneous electromyography (EMG) of the respiratory muscles in patients with chronic obstructive pulmonary disease ( COPD) and healthy subjects during breathing against an inspiratory load. In seven healthy subjects and

  10. Comparison of jaw muscle EMG activity in awake and sleep bruxers

    DEFF Research Database (Denmark)

    Castrillon, Eduardo; Dreyer Nielsen, Patricia; Haugland, Morten

    2015-01-01

    TITLE: Comparison of Jaw Muscle EMG Activity in Awake and Sleep Bruxers AUTHORS: E. E. Castrillon, P. Dreyer, M. Haugland, W. Yachida, T. Arima, P. Svensson AUTHORS/INSTITUTIONS: E.E. Castrillon, P. Dreyer, P. Svensson, Aarhus School of Dentistry, Aarhus C, DENMARK; E.E. Castrillon, P. Svensson......, Scandinavian Center for Orofacial Neuroscience (SCON), Aarhus, DENMARK; M. Haugland, DELTA, Copenhagen, DENMARK; W. Yachida, T. Arima, Hokkaido University, Hokkaido, JAPAN; Group Author Abstracts: ABSTRACT: Objectives: Background: Bruxism has two different circadian manifestations (awake and sleep) that have...... been proposed to have different underlying pathophysiology. Objectives: To compare the characteristics of multiple days EMG assessment of the anterior temporalis muscles between patients with self-reported awake bruxism, sleep bruxism and healthy individuals. Methods: Methods: Participants...

  11. Different fatigue-resistant leg muscles and EMG response during whole-body vibration.

    Science.gov (United States)

    Simsek, Deniz

    2017-12-01

    The purpose of this study was to determine the effects of static whole-body vibration (WBV) on the Electromyograhic (EMG) responses of leg muscles, which are fatigue-resistant in different manner. The study population was divided into two groups according to the values obtained by the Fatigue Index [Group I: Less Fatigue Resistant (LFR), n=11; Group II: More Fatigue Resistant (MFR), n=11]. The repeated electromyographic (EMG) activities of four leg muscles were analyzed the following determinants: (1) frequency (30 Hz, 35 Hz and 40 Hz); (2) stance position (static squat position); (3) amplitude (2 mm and 4 mm) and (4) knee flexion angle (120°), (5) vertical vibration platform. Vibration data were analyzed using Minitab 16 (Minitab Ltd, State College, PA, USA). The significance level was set at pfatigue (pvibration exercise and can serve to guide the development of training programs. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Does EMG activation differ among fatigue-resistant leg muscles ...

    African Journals Online (AJOL)

    ... higher frequencies (max 40Hz) and amplitudes (4mm) (p≤0.001). The results could be useful for the optimal prescription of vibration exercise and can guide the development of training and rehabilitation programmes. Key words: Fatigue; Fatigue resistance; Isokinetic; Rehabilitation; Muscle activation; Electromyography.

  13. Trapezius Muscle EMG as Predictor of Mental Stress

    NARCIS (Netherlands)

    Wijsman, J.L.P; Grundlehner, Bernard; Penders, Julien; Hermens, Hermanus J.

    2010-01-01

    Stress is a growing problem in society and can, amongst others, induce musculoskeletal complaints, related to sustained muscle tension. The ability to measure stress with a wireless system would be useful in the prevention of stress-related health problems. The aim of this experiment was to derive

  14. Real-time muscle state estimation from EMG signals during isometric contractions using Kalman filters.

    Science.gov (United States)

    Menegaldo, Luciano L

    2017-12-01

    State-space control of myoelectric devices and real-time visualization of muscle forces in virtual rehabilitation require measuring or estimating muscle dynamic states: neuromuscular activation, tendon force and muscle length. This paper investigates whether regular (KF) and extended Kalman filters (eKF), derived directly from Hill-type muscle mechanics equations, can be used as real-time muscle state estimators for isometric contractions using raw electromyography signals (EMG) as the only available measurement. The estimators' amplitude error, computational cost, filtering lags and smoothness are compared with usual EMG-driven analysis, performed offline, by integrating the nonlinear Hill-type muscle model differential equations (offline simulations-OS). EMG activity of the three triceps surae components (soleus, gastrocnemius medialis and gastrocnemius lateralis), in three torque levels, was collected for ten subjects. The actualization interval (AI) between two updates of the KF and eKF was also varied. The results show that computational costs are significantly reduced (70x for KF and 17[Formula: see text] for eKF). The filtering lags presented sharp linear relationships with the AI (0-300 ms), depending on the state and activation level. Under maximum excitation, amplitude errors varied in the range 10-24% for activation, 5-8% for tendon force and 1.4-1.8% for muscle length, reducing linearly with the excitation level. Smoothness, measured by the ratio between the average standard variations of KF/eKF and OS estimations, was greatly reduced for activation but converged exponentially to 1 for the other states by increasing AI. Compared to regular KF, extended KF does not seem to improve estimation accuracy significantly. Depending on the particular application requirements, the most appropriate KF actualization interval can be selected.

  15. Cross-spectral analysis of physiological tremor and muscle activity; 1, Theory and application to unsynchronized EMG

    CERN Document Server

    Timmer, J; Pfleger, W; Deuschl, G

    1998-01-01

    We investigate the relationship between the extensor electromyogram (EMG) and tremor time series in physiological hand tremor by cross-spectral analysis. Special attention is directed to the phase spectrum and the effects of observational noise. We calculate the theoretical phase spectrum for a second order linear stochastic process and compare the results to measured tremor data recorded from subjects who did not show a synchronized EMG activity in the corresponding extensor muscle. The results show that physiological tremor is well described by the proposed model and that the measured EMG represents a Newtonian force by which the muscle acts on the hand.

  16. Redundancy or heterogeneity in the electric activity of the biceps brachii muscle? Added value of PCA-processed multi-channel EMG muscle activation estimates in a parallel-fibered muscle.

    Science.gov (United States)

    Staudenmann, Didier; Stegeman, Dick F; van Dieën, Jaap H

    2013-08-01

    Conventional bipolar EMG provides imprecise muscle activation estimates due to possibly heterogeneous activity within muscles and due to improper alignment of the electrodes with the muscle fibers. Principal component analysis (PCA), applied on multi-channel monopolar EMG yielded substantial improvements in muscle activation estimates in pennate muscles. We investigated the degree of heterogeneity in muscle activity and the contribution of PCA to muscle activation estimates in biceps brachii (BB), which has a relatively simply parallel-fibered architecture. EMG-based muscle activation estimates were assessed by comparison to elbow flexion forces in isometric, two-state isotonic contractions in eleven healthy male subjects. Monopolar EMG was collected over the entire surface of the BB with about 63 electrodes. Estimation quality of different combinations of EMG channels showed that heterogeneous activation was found mainly in medio-lateral direction, whereas adding channels in the longitudinal direction added largely redundant information. Multi-channel bipolar EMG amplitude improved muscle activation estimates by 5-14% as compared to a single bipolar. PCA-processed monopolar EMG amplitude yielded a further improvement of (12-22%). Thus multi-channel EMG, processed with PCA, substantially improves the quality of muscle activation estimates compared conventional bipolar EMG in BB. Copyright © 2013. Published by Elsevier Ltd.

  17. Young, Healthy Subjects Can Reduce the Activity of Calf Muscles When Provided with EMG Biofeedback in Upright Stance

    Science.gov (United States)

    Vieira, Taian M.; Baudry, Stéphane; Botter, Alberto

    2016-01-01

    Recent evidence suggests the minimization of muscular effort rather than of the size of bodily sway may be the primary, nervous system goal when regulating the human, standing posture. Different programs have been proposed for balance training; none however has been focused on the activation of postural muscles during standing. In this study we investigated the possibility of minimizing the activation of the calf muscles during standing through biofeedback. By providing subjects with an audio signal that varied in amplitude and frequency with the amplitude of surface electromyograms (EMG) recorded from different regions of the gastrocnemius and soleus muscles, we expected them to be able to minimize the level of muscle activation during standing without increasing the excursion of the center of pressure (CoP). CoP data and surface EMG from gastrocnemii, soleus and tibialis anterior muscles were obtained from 10 healthy participants while standing at ease and while standing with EMG biofeedback. Four sensitivities were used to test subjects' responsiveness to the EMG biofeedback. Compared with standing at ease, the two most sensitive feedback conditions induced a decrease in plantar flexor activity (~15%; P < 0.05) and an increase in tibialis anterior EMG (~10%; P < 0.05). Furthermore, CoP mean position significantly shifted backward (~30 mm). In contrast, the use of less sensitive EMG biofeedback resulted in a significant decrease in EMG activity of ankle plantar flexors with a marginal increase in TA activity compared with standing at ease. These changes were not accompanied by greater CoP displacements or significant changes in mean CoP position. Key results revealed subjects were able to keep standing stability while reducing the activity of gastrocnemius and soleus without loading their tibialis anterior muscle when standing with EMG biofeedback. These results may therefore posit the basis for the development of training protocols aimed at assisting subjects in

  18. Young, healthy subjects can reduce the activity of calf muscles when provided with EMG biofeedback in upright stance

    Directory of Open Access Journals (Sweden)

    Taian M. Vieira

    2016-04-01

    Full Text Available Recent evidence suggests the minimisation of muscular effort rather than of the size of bodily sway may be the primary, nervous system goal when regulating the human, standing posture. Different programs have been proposed for balance training; none however has been focused on the activation of postural muscles during standing. In this study we investigated the possibility of minimising the activation of the calf muscles during standing through biofeedback. By providing subjects with an audio signal that varied in amplitude and frequency with the amplitude of surface electromyograms (EMG recorded from different regions of the gastrocnemius and soleus muscles, we expected them to be able to minimise the level of muscle activation during standing without increasing the excursion of the centre of pressure (CoP. CoP data and surface EMG from gastrocnemii, soleus and tibialis anterior muscles were obtained from ten healthy participants while standing at ease and while standing with EMG biofeedback. Four sensitivities were used to test subjects’ responsiveness to the EMG biofeedback. Compared with standing at ease, the two most sensitive feedback conditions induced a decrease in plantar flexor activity (~15%; P<0.05 and an increase in tibialis anterior EMG (~10%; P<0.05. Furthermore, CoP mean position significantly shifted backward (~30 mm. In contrast, the use of less sensitive EMG biofeedback resulted in a significant decrease in EMG activity of ankle plantar flexors with a marginal increase in TA activity compared with standing at ease. These changes were not accompanied by greater CoP displacements or significant changes in mean CoP position. Key results revealed subjects were able to keep standing stability while reducing the activity of gastrocnemius and soleus without loading their tibialis anterior muscle when standing with EMG biofeedback. These results may therefore posit the basis for the development of training protocols aimed at

  19. EMG burst presence probability: a joint time-frequency representation of muscle activity and its application to onset detection.

    Science.gov (United States)

    Liu, Jie; Ying, Dongwen; Rymer, William Zev

    2015-04-13

    The purpose of this study was to quantify muscle activity in the time-frequency domain, therefore providing an alternative tool to measure muscle activity. This paper presents a novel method to measure muscle activity by utilizing EMG burst presence probability (EBPP) in the time-frequency domain. The EMG signal is grouped into several Mel-scale subbands, and the logarithmic power sequence is extracted from each subband. Each log-power sequence can be regarded as a dynamic process that transits between the states of EMG burst and non-burst. The hidden Markov model (HMM) was employed to elaborate this dynamic process since HMM is intrinsically advantageous in modeling the temporal correlation of EMG burst/non-burst presence. The EBPP was eventually yielded by HMM based on the criterion of maximum likelihood. Our approach achieved comparable performance with the Bonato method. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. Computational Intelligence Based Data Fusion Algorithm for Dynamic sEMG and Skeletal Muscle Force Modelling

    Energy Technology Data Exchange (ETDEWEB)

    Chandrasekhar Potluri,; Madhavi Anugolu; Marco P. Schoen; D. Subbaram Naidu

    2013-08-01

    In this work, an array of three surface Electrography (sEMG) sensors are used to acquired muscle extension and contraction signals for 18 healthy test subjects. The skeletal muscle force is estimated using the acquired sEMG signals and a Non-linear Wiener Hammerstein model, relating the two signals in a dynamic fashion. The model is obtained from using System Identification (SI) algorithm. The obtained force models for each sensor are fused using a proposed fuzzy logic concept with the intent to improve the force estimation accuracy and resilience to sensor failure or misalignment. For the fuzzy logic inference system, the sEMG entropy, the relative error, and the correlation of the force signals are considered for defining the membership functions. The proposed fusion algorithm yields an average of 92.49% correlation between the actual force and the overall estimated force output. In addition, the proposed fusionbased approach is implemented on a test platform. Experiments indicate an improvement in finger/hand force estimation.

  1. Effect of PNF stretch techniques on knee flexor muscle EMG activity in older adults.

    Science.gov (United States)

    Ferber, R; Osternig, L; Gravelle, D

    2002-10-01

    The effects of proprioceptive neuromuscular facilitation (PNF) stretch techniques on older adults are unknown and the physiological changes associated with aging may lead to differential responses to PNF stretching. Therefore, the purpose of this experiment was to examine the effects of PNF stretch techniques and EMG activity in older adults. Three PNF stretch techniques: static stretch (SS), contract-relax (CR), and agonist contract-relax (ACR) were applied to 24 older adults aged 50-75 years. The subjects were tested for knee extension range of motion (ROM) and knee flexor muscle EMG activity. The results indicated that ACR produced 29-34% more ROM and 65-119% more EMG activity than CR and SS, respectively. It was concluded that PNF stretch techniques can increase ROM in older adults. However, a paradoxical effect was observed in that PNF stretching may not induce muscular relaxation even though ROM about a joint increases. Care should be taken when applying PNF stretch techniques to older adults due to age-related alterations in muscle elasticity.

  2. Identification of Onset Of Fatigue in Biceps Brachii Muscles Using Surface EMG and Multifractal DMA Alogrithm.

    Science.gov (United States)

    Marri, Kiran; Swaminathan, Ramakrishnan

    2015-01-01

    Prolonged and repeated fatigue conditions can cause muscle damage and adversely impact coordination in dynamic contractions. Hence it is important to determine the onset of muscle fatigue (OMF) in clinical rehabilitation and sports medicine. The aim of this study is to propose a method for analyzing surface electromyography (sEMG) signals and identify OMF using multifractal detrending moving average algorithm (MFDMA). Signals are recorded from biceps brachii muscles of twenty two healthy volunteers while performing standard curl exercise. The first instance of muscle discomfort during curl exercise is considered as experimental OMF. Signals are pre-processed and divided into 1-second epoch for MFDMA analysis. Degree of multifractality (DOM) feature is calculated from multifractal spectrum. Further, the variance of DOM is computed and OMF is calculated from instances of high peaks. The analysis is carried out by dividing the entire duration into six equal zones for time axis normalization. High peaks are observed in zones where subjects reported muscle discomfort. First muscle discomfort occurred in third and forth zones for majority of subjects. The calculated and experimental muscle discomfort zone closely matched in 72% of subjects indicating that multifractal technique may be a good method for detecting onset of fatigue. The experimental data may have an element of subjectivity in identifying muscle discomfort. This work can also be useful to analyze progressive changes in muscle dynamics in neuromuscular condition and co-contraction activity.

  3. EMG activity of trunk stabilizer muscles during Centering Principle of Pilates Method.

    Science.gov (United States)

    Marques, Nise Ribeiro; Morcelli, Mary Hellen; Hallal, Camilla Zamfolini; Gonçalves, Mauro

    2013-04-01

    This study aimed to analyze the electromyographic (EMG) activity of iliocostalis lumborum (IL), internal oblique (IO) and multifidus (MU) and the antagonist cocontraction (IO/MU and IO/IL) during the performance of Centering Principle of Pilates Method. Participating in this study were eighteen young and physically fit volunteers, without experience in Pilates Method, divided in two groups: low back pain group (LBPG, n = 8) and control group (CG, n = 10). Two isometric contractions of IO muscles (Centering Principle) were performed in upright sitting posture. EMG signal amplitude was calculated by Root Mean Square (RMS), which was normalized by RMS maximum value. The common area method to calculate the antagonist cocontraction index was used. MU and IO activation and IO/MU cocontraction (p Pilates Method. Copyright © 2012 Elsevier Ltd. All rights reserved.

  4. Comparison between {sup 18}F-FDG PET/CT and EMG Mapping for Identifying Dystonic Superficial Muscles in Primary Cervical Dystonia: Preliminary Results

    Energy Technology Data Exchange (ETDEWEB)

    Jang, Su Jin [Seoul National University School, Seoul (Korea, Republic of); Choi, Joon Young; Sung, Duk Hyun; Park, Kwang Hong; Lee, Ji Young; Cho, Sook Kyung; Yu, Jang; Lee, Kyung Han; Kim, Byung Tae [Sungkyunkawn University School of Medicine, Seoul (Korea, Republic of)

    2010-04-15

    This study was conducted to compare {sup 18}F-FDG PET/CT and electromyography (EMG) mapping in patients with primary cervical dystonia (PCD) to find dystonic superficial cervical muscles. Ten consecutive patients with PCD (M:F=5:5, age 44{+-}13 years) whose dystonic posture was not relieved with conventional muscle relaxant therapy were included. Target cervical muscles for the comparison between {sup 18}F-FDG PET/CT and EMG mapping were four representative superficial bilateral cervical muscles: splenius capitis muscle, sternocleidomstoid muscle, upper trapeziums muscle, and levitator scapulae muscle. The diagnostic efficacy was compared between {sup 18}F-FDG PET/CT and EMG mapping using physical exam and measurement of rotation angle as the gold standard. Among 80 muscles evaluated, there were 21 (26%) dystonic superficial cervical muscles assessed with physical exam and motion analysis. The sensitivity, specificity, and accuracy for localizing dystonic muscles were 76, 92, and 88% for {sup 18}F-FDG PET/CT, and 95, 66, and 74% for EMG mapping, respectively. The sensitivity of EMG mapping was significantly higher than that of {sup 18}F-FDG PET/CT. In contrast, {sup 18}F-FDG PET/CT is more specific and accurate than EMG mapping for finding superficial dystonic cervical muscles. The high sensitivity of EMG mapping suggests that {sup 18}F-FDG PET/CT and EMG mapping are complementary for finding dystonic superficial cervical muscles.

  5. The Effectiveness of FES-Evoked EMG Potentials to Assess Muscle Force and Fatigue in Individuals with Spinal Cord Injury

    Directory of Open Access Journals (Sweden)

    Morufu Olusola Ibitoye

    2014-07-01

    Full Text Available The evoked electromyographic signal (eEMG potential is the standard index used to monitor both electrical changes within the motor unit during muscular activity and the electrical patterns during evoked contraction. However, technical and physiological limitations often preclude the acquisition and analysis of the signal especially during functional electrical stimulation (FES-evoked contractions. Hence, an accurate quantification of the relationship between the eEMG potential and FES-evoked muscle response remains elusive and continues to attract the attention of researchers due to its potential application in the fields of biomechanics, muscle physiology, and rehabilitation science. We conducted a systematic review to examine the effectiveness of eEMG potentials to assess muscle force and fatigue, particularly as a biofeedback descriptor of FES-evoked contractions in individuals with spinal cord injury. At the outset, 2867 citations were identified and, finally, fifty-nine trials met the inclusion criteria. Four hypotheses were proposed and evaluated to inform this review. The results showed that eEMG is effective at quantifying muscle force and fatigue during isometric contraction, but may not be effective during dynamic contractions including cycling and stepping. Positive correlation of up to r = 0.90 (p < 0.05 between the decline in the peak-to-peak amplitude of the eEMG and the decline in the force output during fatiguing isometric contractions has been reported. In the available prediction models, the performance index of the eEMG signal to estimate the generated muscle force ranged from 3.8% to 34% for 18 s to 70 s ahead of the actual muscle force generation. The strength and inherent limitations of the eEMG signal to assess muscle force and fatigue were evident from our findings with implications in clinical management of spinal cord injury (SCI population.

  6. Frenulectomy of the tongue and the influence of rehabilitation exercises on the sEMG activity of masticatory muscles.

    Science.gov (United States)

    Tecco, Simona; Baldini, Aberto; Mummolo, Stefano; Marchetti, Enrico; Giuca, Maria Rita; Marzo, Giuseppe; Gherlone, Enrico Felice

    2015-08-01

    This study aimed to assess by surface electromyography (sEMG) the changes in sub-mental, orbicularis oris, and masticatory muscle activity after a lingual frenulectomy. Rehabilitation exercises in subjects with ankyloglossia, characterized by Class I malocclusion, were assessed as well. A total of 24 subjects were selected. Thirteen subjects (mean age 7±2.5years) with Class I malocclusion and ankyloglossia were treated with lingual frenulectomy and rehabilitation exercises, while 11 subjects (mean age 7±0.8years) with normal occlusion and normal lingual frenulum were used as controls. The inclusion criteria for both groups were the presence of mixed dentition and no previous orthodontic treatment. The sEMG recordings were taken at the time of the first visit (T0), and after 1 (T1) and 6months (T2) for the treated group. Recordings were taken at the same time for the control group. Due to the noise inherent with the sEMG recording, special attention was paid to obtain reproducible and standardized recordings. The tested muscles were the masseter, anterior temporalis, upper and lower orbicularis oris, and sub-mental muscles. The sEMG recordings were performed at rest, while kissing, swallowing, opening the mouth, clenching the teeth and during protrusion of the mandible. These recordings were made by placing electrodes in the area of muscle contraction. At T0, the treated group showed different sEMG activity of the muscles with respect to the control group, with significant differences at rest and during some test tasks (pmuscle, from T0 to T2, during maximal voluntary clenching. During swallowing and kissing, the masseter and sub-mental muscles showed a significant increase in their sEMG potentials from T0 to T2. During the protrusion of the mandible, the masseter and anterior temporalis significantly decreased their sEMG activity, while the sub-mental area increased significantly. No significant change was observed in the control group during the follow-up. The sEMG

  7. Statistical Parametric Mapping (SPM) for alpha-based statistical analyses of multi-muscle EMG time-series.

    Science.gov (United States)

    Robinson, Mark A; Vanrenterghem, Jos; Pataky, Todd C

    2015-02-01

    Multi-muscle EMG time-series are highly correlated and time dependent yet traditional statistical analysis of scalars from an EMG time-series fails to account for such dependencies. This paper promotes the use of SPM vector-field analysis for the generalised analysis of EMG time-series. We reanalysed a publicly available dataset of Young versus Adult EMG gait data to contrast scalar and SPM vector-field analysis. Independent scalar analyses of EMG data between 35% and 45% stance phase showed no statistical differences between the Young and Adult groups. SPM vector-field analysis did however identify statistical differences within this time period. As scalar analysis failed to consider the multi-muscle and time dependence of the EMG time-series it exhibited Type II error. SPM vector-field analysis on the other hand accounts for both dependencies whilst tightly controlling for Type I and Type II error making it highly applicable to EMG data analysis. Additionally SPM vector-field analysis is generalizable to linear and non-linear parametric and non-parametric statistical models, allowing its use under constraints that are common to electromyography and kinesiology. Copyright © 2014 Elsevier Ltd. All rights reserved.

  8. Multifractal analysis of sEMG signal of the complex muscle activity

    CERN Document Server

    Trybek, Paulina; Nowakowski, Michal; Machura, Lukasz

    2014-01-01

    The neuro--muscular activity while working on laparoscopic trainer is the example of the complex (and complicated) movement. This class of problems are still waiting for the proper theory which will be able to describe the actual properties of the muscle performance. Here we consider the signals obtained from three states of muscle activity: at maximum contraction, during complex movements (at actual work) and in the completely relaxed state. In addition the difference between a professional and an amateur is presented. The Multifractal Detrended Fluctuation Analysis was used in description of the properties the kinesiological surface electromyographic signals (sEMG). We demonstrate the dissimilarity between each state of work for the selected group of muscles as well as between trained and untrained individuals.

  9. Real time estimation of generation, extinction and flow of muscle fibre action potentials in high density surface EMG.

    Science.gov (United States)

    Mesin, Luca

    2015-02-01

    Developing a real time method to estimate generation, extinction and propagation of muscle fibre action potentials from bi-dimensional and high density surface electromyogram (EMG). A multi-frame generalization of an optical flow technique including a source term is considered. A model describing generation, extinction and propagation of action potentials is fit to epochs of surface EMG. The algorithm is tested on simulations of high density surface EMG (inter-electrode distance equal to 5mm) from finite length fibres generated using a multi-layer volume conductor model. The flow and source term estimated from interference EMG reflect the anatomy of the muscle, i.e. the direction of the fibres (2° of average estimation error) and the positions of innervation zone and tendons under the electrode grid (mean errors of about 1 and 2mm, respectively). The global conduction velocity of the action potentials from motor units under the detection system is also obtained from the estimated flow. The processing time is about 1 ms per channel for an epoch of EMG of duration 150 ms. A new real time image processing algorithm is proposed to investigate muscle anatomy and activity. Potential applications are proposed in prosthesis control, automatic detection of optimal channels for EMG index extraction and biofeedback. Copyright © 2014 Elsevier Ltd. All rights reserved.

  10. Cross-spectral analysis of physiological tremor and muscle activity; 2, Application to synchronized EMG

    CERN Document Server

    Timmer, J; Pfleger, W; Deuschl, G

    1998-01-01

    We investigate the relationship between synchronized muscle activity and tremor time series in (enhanced) physiological tremor by cross-spectral analysis. Special attention is directed to the phase spectrum and its possibilities to clarify the contribution of reflex mechanisms to physiological tremor. The phase spectra are investigated under the assumptions that the EMG synchronization was caused by a reflex, respectively a central oscillator. In comparison of these results to phase spectra of measured data we found a significant contribution of reflexes. But reflexes only modify existing peaks in the power spectrum. The main agents of physiological tremor are an efferent pace and the resonant behavior of the biomechanical system.

  11. Muscle-tendon units localization and activation level analysis based on high-density surface EMG array and NMF algorithm

    Science.gov (United States)

    Huang, Chengjun; Chen, Xiang; Cao, Shuai; Zhang, Xu

    2016-12-01

    Objective. Some skeletal muscles can be subdivided into smaller segments called muscle-tendon units (MTUs). The purpose of this paper is to propose a framework to locate the active region of the corresponding MTUs within a single skeletal muscle and to analyze the activation level varieties of different MTUs during a dynamic motion task. Approach. Biceps brachii and gastrocnemius were selected as targeted muscles and three dynamic motion tasks were designed and studied. Eight healthy male subjects participated in the data collection experiments, and 128-channel surface electromyographic (sEMG) signals were collected with a high-density sEMG electrode grid (a grid consists of 8 rows and 16 columns). Then the sEMG envelopes matrix was factorized into a matrix of weighting vectors and a matrix of time-varying coefficients by nonnegative matrix factorization algorithm. Main results. The experimental results demonstrated that the weightings vectors, which represent invariant pattern of muscle activity across all channels, could be used to estimate the location of MTUs and the time-varying coefficients could be used to depict the variation of MTUs activation level during dynamic motion task. Significance. The proposed method provides one way to analyze in-depth the functional state of MTUs during dynamic tasks and thus can be employed on multiple noteworthy sEMG-based applications such as muscle force estimation, muscle fatigue research and the control of myoelectric prostheses. This work was supported by the National Nature Science Foundation of China under Grant 61431017 and 61271138.

  12. The effectiveness of FES-evoked EMG potentials to assess muscle force and fatigue in individuals with spinal cord injury.

    Science.gov (United States)

    Ibitoye, Morufu Olusola; Estigoni, Eduardo H; Hamzaid, Nur Azah; Wahab, Ahmad Khairi Abdul; Davis, Glen M

    2014-07-14

    The evoked electromyographic signal (eEMG) potential is the standard index used to monitor both electrical changes within the motor unit during muscular activity and the electrical patterns during evoked contraction. However, technical and physiological limitations often preclude the acquisition and analysis of the signal especially during functional electrical stimulation (FES)-evoked contractions. Hence, an accurate quantification of the relationship between the eEMG potential and FES-evoked muscle response remains elusive and continues to attract the attention of researchers due to its potential application in the fields of biomechanics, muscle physiology, and rehabilitation science. We conducted a systematic review to examine the effectiveness of eEMG potentials to assess muscle force and fatigue, particularly as a biofeedback descriptor of FES-evoked contractions in individuals with spinal cord injury. At the outset, 2867 citations were identified and, finally, fifty-nine trials met the inclusion criteria. Four hypotheses were proposed and evaluated to inform this review. The results showed that eEMG is effective at quantifying muscle force and fatigue during isometric contraction, but may not be effective during dynamic contractions including cycling and stepping. Positive correlation of up to r = 0.90 (p force output during fatiguing isometric contractions has been reported. In the available prediction models, the performance index of the eEMG signal to estimate the generated muscle force ranged from 3.8% to 34% for 18 s to 70 s ahead of the actual muscle force generation. The strength and inherent limitations of the eEMG signal to assess muscle force and fatigue were evident from our findings with implications in clinical management of spinal cord injury (SCI) population.

  13. Toward EMG-controlled force field generation for training and rehabilitation: From movement data to muscle geometry.

    Science.gov (United States)

    Lotti, Nicola; Sanguinati, Vittorio

    2017-07-01

    EMG signals are often used to control prostheses or assistive devices, but have been rarely used in rehabilitation. We propose a novel approach to personalised rehabilitation, based on EMG-driven force field adaptation. As a step toward this direction, here we show how EMG activity and movement data during a robot-assisted motor task can be used to estimate muscle geometry. We compare three different models of muscle geometry, characterised by (i) constant moment arms (CM); (ii) a normative model, based on polynomial functions of joint angles with fixed coefficients (normative polynomial, NP); and (iii) a person-adaptive model, in which the same polynomial model is fitted to individual subjects data (fitted polynomial, FP). We found that the FP model has the best performance, specially for subjects whose size is farther from 'average'. The fitting results also emphasise the adverse effect of muscles co-contraction.

  14. The basis and functional role of the late EMG activity in human forearm muscles following wrist displacement.

    Science.gov (United States)

    Goodin, D S; Aminoff, M J

    1992-08-28

    The present paper examines the hypothesis that the long latency EMG activity produced by muscle stretch is the result of long loop reflex pathways involved in the control of limb stiffness. We recorded the cerebral responses and late EMG activity in agonist and antagonist muscles following sudden stretch of the wrist extensor muscles under 4 experimental conditions in 11 subjects. In each experiment subjects held their right wrist extended isometrically against a constant force of 2.3 N and a trial was begun with a step increase in the force from 2.3 N to 18.4 N, to stretch the extensor muscle. In the first and second experiments the force change occurred unpredictably and subjects had to either oppose the perturbation (Unpredictable Oppose) or relax the forearm muscles once the increase in force was detected (Unpredictable Let-Go). In the third and fourth experiments the force change occurred predictably when subjects pressed a thumb switch with the left hand to cause it. As before, subjects were instructed to either oppose the perturbation (Predictable Oppose) or relax the forearm muscles (Predictable Let-Go). Responses were recorded from the flexor and extensor carpi radialis muscles and from the scalp. When the perturbing force occurred unpredictably, early latency EMG activity (the MI response) was seen in the stretched extensor muscle, and longer latency EMG activity was seen simultaneously in both extensor and flexor muscles. When the force change occurred predictably the late EMG activity was considerably attenuated, especially in the Predictable Let-Go condition. Cerebral responses similarly depended upon the predictability of the perturbation.(ABSTRACT TRUNCATED AT 250 WORDS)

  15. Modified track shoes and their effect on the EMG activity of calf muscles.

    Science.gov (United States)

    Greensword, Marlon; Aghazadeh, Fereydoun; Al-Qaisi, Saif

    2012-01-01

    Although track and field spike shoes are crafted for runners, these shoes are not designed for regular walking. With such shoes, runners may eventually encounter serious chronic injuries such as plantar fasciitis, shin splints, achilles tendinitis, chondromalacia, and iliotibial band syndrome. To address this problem, a modified spike shoe was tested and compared to a regular spike shoe. The modification consists of adding a removable heel to the shoe sole in order to reduce the flexion of the foot and properly level the foot for walking. Nine healthy participants performed walking drills at 2 and 3 mph, using the original and the modified shoes. Electromyography (EMG) measurements were used to evaluate muscle activities. Participants also rated their discomfort on a 0-10 scale. Results show that the use of modified shoes resulted in a reduction of 22% and 24.25% EMG activity for the tibialis and gastrocnemius muscles, respectively. Comfort ratings increased by an average of 2.7, 2.6, 3.9, and 4.2 points at the knees, calves, ankles, and feet, respectively.

  16. Muscle synergy control model-tuned EMG driven torque estimation system with a musculo-skeletal model.

    Science.gov (United States)

    Min, Kyuengbo; Shin, Duk; Lee, Jongho; Kakei, Shinji

    2013-01-01

    Muscle activity is the final signal for motion control from the brain. Based on this biological characteristic, Electromyogram (EMG) signals have been applied to various systems that interface human with external environments such as external devices. In order to use EMG signals as input control signal for this kind of system, the current EMG driven torque estimation models generally employ the mathematical model that estimates the nonlinear transformation function between the input signal and the output torque. However, these models need to estimate too many parameters and this process cause its estimation versatility in various conditions to be poor. Moreover, as these models are designed to estimate the joint torque, the input EMG signals are tuned out of consideration for the physiological synergetic contributions of multiple muscles for motion control. To overcome these problems of the current models, we proposed a new tuning model based on the synergy control mechanism between multiple muscles in the cortico-spinal tract. With this synergetic tuning model, the estimated contribution of multiple muscles for the motion control is applied to tune the EMG signals. Thus, this cortico-spinal control mechanism-based process improves the precision of torque estimation. This system is basically a forward dynamics model that transforms EMG signals into the joint torque. It should be emphasized that this forward dynamics model uses a musculo-skeletal model as a constraint. The musculo-skeletal model is designed with precise musculo-skeletal data, such as origins and insertions of individual muscles or maximum muscle force. Compared with the mathematical model, the proposed model can be a versatile model for the torque estimation in the various conditions and estimates the torque with improved accuracy. In this paper, we also show some preliminary experimental results for the discussion about the proposed model.

  17. Technical Device for Prevention of Spinal Column Disorders. Pilot EMG Study for Estimation of Back Muscle Activity

    Directory of Open Access Journals (Sweden)

    Rositza Raikova

    2011-07-01

    Full Text Available One possible cause of abnormal spinal column curvatures in adolescents is standing in “bad posture” for a long time. If this bad habit can be corrected on time, by creating a dynamic stereotype for correct body position maintenance, further health problems can be avoided. To present a technical device for prevention of scoliotic deformations signaling when the angles of inclination forward or sideward are bigger than preliminary set ones. To elaborate an experimental protocol based on analysis of EMG activity (EMGs of spine muscles for verification of its effect. Study design: Devising of the device and of software for EMGs processing. Pilot experiments were conducted recording EMGs of eight spinal muscles for estimation of the device efficiency. Different mathematical procedures were proposed and programmed for data processing and illustration. Two device prototypes (with sound and vibration signal are developed and experimentally used. EMG data from 20 motor tasks (half of them with carrying the device are processed. The device can be used as a simple tool for biofeedback-type pupil teaching of dynamic stereotype for right posture maintenance. The developed software for EMGs processing can be used for tracing the effect of using the device.

  18. Uncoupling of in vivo torque production from EMG in mouse muscles injured by eccentric contractions

    Science.gov (United States)

    Warren, Gordon L; Ingalls, Christopher P; Shah, Shree J; Armstrong, R B

    1999-01-01

    The main objective of this study was to determine whether eccentric contraction-induced muscle injury causes impaired plasmalemmal action potential conduction, which could explain the injury-induced excitation-contraction coupling failure. Mice were chronically implanted with stimulating electrodes on the left common peroneal nerve and with electromyographic (EMG) electrodes on the left tibialis anterior (TA) muscle. The left anterior crural muscles of anaesthetized mice were stimulated to perform 150 eccentric (ECC) (n = 12 mice) or 150 concentric (CON) (n = 11 mice) contractions. Isometric torque, EMG root mean square (RMS) and M-wave mean and median frequencies were measured before, immediately after, and at 1, 3, 5 and 14 days after the protocols. In parallel experiments, nicotinic acetylcholine receptor (AChR) concentration was measured in TA muscles to determine whether the excitation failure elicited a denervation-like response.Immediately after the ECC protocol, torque was reduced by 47–89%, while RMS was reduced by 9–21%; the RMS decrement was not different from that observed for the CON protocol, which did not elicit large torque deficits. One day later, both ECC and CON RMS had returned to baseline values and did not change over the next 2 weeks. However, torque production by the ECC group showed a slow recovery over that time and was still depressed by 12–30% after 2 weeks. M-wave mean and median frequencies were not affected by performance of either protocol.AChR concentration was elevated by 79 and 368% at 3 and 5 days, respectively, after the ECC protocol; AChR concentration had returned to control levels 2 weeks after the protocol. At the time of peak AChR concentration in the ECC protocol muscles (i.e. 5 days), AChR concentration in CON protocol muscles was not different from the control level.In conclusion, these data demonstrate no major role for impaired plasmalemmal action potential conduction in the excitation-contraction coupling

  19. Power spectral analysis of surface electromyography (EMG) at matched contraction levels of the first dorsal interosseous muscle in stroke survivors.

    Science.gov (United States)

    Li, Xiaoyan; Shin, Henry; Zhou, Ping; Niu, Xun; Liu, Jie; Rymer, William Zev

    2014-05-01

    The objective of this study was to help assess complex neural and muscular changes induced by stroke using power spectral analysis of surface electromyogram (EMG) signals. Fourteen stroke subjects participated in the study. They were instructed to perform isometric voluntary contractions by abducting the index finger. Surface EMG signals were collected from the paretic and contralateral first dorsal interosseous (FDI) muscles with forces ranging from 30% to 70% maximum voluntary contraction (MVC) of the paretic muscle. Power spectral analysis was performed to characterize features of the surface EMG in paretic and contralateral muscles at matched forces. A Linear Mixed Model was applied to identify the spectral changes in the hemiparetic muscle and to examine the relation between spectral parameters and contraction levels. Regression analysis was performed to examine the correlations between spectral characteristics and clinical features. Differences in power spectrum distribution patterns were observed in paretic muscles when compared with their contralateral pairs. Nine subjects showed increased mean power frequency (MPF) in the contralateral side (>15 Hz). No evident spectrum difference was observed in 3 subjects. Only 2 subjects had higher MPF in the paretic muscle than the contralateral muscle. Pooling all subjects' data, there was a significant reduction of MPF in the paretic muscle compared with the contralateral muscle (paretic: 168.7 ± 7.6 Hz, contralateral: 186.1 ± 8.7 Hz, mean ± standard error, F=36.56, pEMG power spectrum did not confirm a significant correlation between the MPF and contraction force in either hand (F=0.7, p>0.5). There was no correlation between spectrum difference and Fugl-Meyer or Chedoke scores, or ratio of paretic and contralateral MVC (p>0.2). There appears to be complex muscular and neural processes at work post stroke that may impact the surface EMG power spectrum. The majority of the tested stroke subjects had lower MPF in

  20. The effects of whole body vibration on EMG activity of the upper extremity muscles in static modified push up position.

    Science.gov (United States)

    Ashnagar, Zinat; Shadmehr, Azadeh; Hadian, Mohammadreza; Talebian, Saeed; Jalaei, Shohreh

    2016-08-10

    Whole Body Vibration (WBV) has been reported to change neuromuscular activity which indirectly assessed by electromyography (EMG). Although researches regarding the influence of WBV on EMG activity of the upper extremity muscles are in their infancy, contradictory findings have been reported as a result of dissimilar protocols. The purpose of this study was to investigate the effects of WBV on electromyography (EMG) activity of upper extremity muscles in static modified push up position. Forty recreationally active females were randomly assigned in WBV and control groups. Participants in WBV group received 5 sets of 30 seconds vibration at 5 mm (peak to peak) and 30 Hz by using vibratory platform. No vibration stimulus was used in the control group. Surface EMG was recorded from Upper Trapezius (UT), Serratus Anterior (SA), Biceps Brachii (BB) and Triceps Brachii (TB) muscles before, during and after the vibration protocol while the subjects maintained the static modified push up position. EMG signals were expressed as root mean square (EMGrms) and normalized by maximum voluntary exertion (MVE). EMGrms activity of the studied muscles increased significantly during the vibration protocol in the WBV group comparing to the control group (P ≤ 0.05). The results indicated that vibration stimulus transmitting via hands increased muscle activity of UT, SA, BB and TB muscles by an average of 206%, 60%, 106% and 120%, respectively, comparing to pre vibration values. These findings suggest that short exposure to the WBV could increase the EMGrms activity of the upper extremity muscles in the static modified push-up position. However, more sessions of WBV application require for a proper judgment.

  1. EMG control of a bionic knee prosthesis: exploiting muscle co-contractions for improved locomotor function.

    Science.gov (United States)

    Dawley, James A; Fite, Kevin B; Fulk, George D

    2013-06-01

    This paper presents the development and experimental evaluation of a volitional control architecture for a powered-knee transfemoral prosthesis that affords the amputee user with direct control of knee impedance using measured electromyogram (EMG) potentials of antagonist muscles in the residual limb. The control methodology incorporates a calibration procedure performed with each donning of the prosthesis that characterizes the co-contraction levels as the user performs volitional phantom-knee flexor and extensor contractions. The performance envelope for EMG control of impedance is then automatically shaped based on the flexor and extensor calibration datasets. The result is a control architecture that is optimized to the user's current co-contraction activity, providing performance robustness to variation in sensor placement or physiological changes in the residual-limb musculature. Experimental results with a single unilateral transfemoral amputee user demonstrate consistent and repeatable control performance for level walking at self-selected speed over a multi-week, multi-session period of evaluation.

  2. Reliable MRI and MRN signs of nerve and muscle injury following trauma to the shoulder with EMG and

    Directory of Open Access Journals (Sweden)

    Omar Ahmed Hassanien

    2016-09-01

    Full Text Available Purpose: To evaluate the role of MRN in diagnosis of suprascapular nerve injury and its relation with muscle injury after shoulder trauma in comparison with the EMG results. Patient & method: The study was carried on 30 patients following trauma to the shoulder, either direct trauma (80% or indirect trauma in 20% presented clinically with shoulder pain and limited movements and referred for MRI examination. The MRI results were correlated with EMG results for all cases. Results: Those 30 cases were divided into 13 cases with acute onset, 10 cases with subacute onset and 7 cases with chronic onset. In acute injuries, 5 cases (5/30 showed combined nerve and muscle injuries, 4 cases (4/30 showed nerve injury only and 5 cases (5/30 showed muscle injury only. In subacute injuries 5 cases (5/30 showed combined muscle and nerve injuries and 5 cases (5/30 showed muscle injury only, in chronic 7 cases (7/30 showed combined nerve and muscle injuries, where EMG showed sharp waves only in 7 cases which are all chronic. Conclusion: MRN is the best modality in diagnosis of nerve injuries and associated muscle injuries in one sitting with no obvious difficulties in the examination. MRN associating with the routine MRI elevated the sensitivity of diagnosis.

  3. Locomotor changes in length and EMG activity of feline medial gastrocnemius muscle following paralysis of two synergists

    NARCIS (Netherlands)

    Maas, H.; Gregor, R.J.; Hodson-Tole, E.F.; Farrell, B.J.; English, A.W.; Prilutsky, B.I.

    2010-01-01

    The mechanism of the compensatory increase in electromyographic activity (EMG) of a cat ankle extensor during walking shortly after paralysis of its synergists is not fully understood. It is possible that due to greater ankle Xexion in stance in this situation, muscle spindles are stretched to a

  4. EMG responses of the vertical eye muscles to dynamic and static natural vestibular stimulation about different axes in alert rabbits.

    Science.gov (United States)

    Favilla, M; Ghelarducci, B; La Noce, A; Starita, A

    1983-12-05

    The EMG responses of the vertical eye muscles have been recorded in alert intact rabbits submitted to both dynamic and static natural vestibular stimulations about different axes. Following dynamic vestibular stimulation, the phase lead of the EMG response with respect to head position as well as its sensitivity increased with stimulus frequency in all the stimulation modalities. This indicates a progressive recruitment by the stimulus of the second-order vestibular neurons related to semicircular canals. The sensitivity of the response was consistently higher in the effective intermediate roll-pitch modality for all the 4 muscles. Following static stimulation, the EMG response showed an asymmetric modulation. The excitatory response was always higher than the inhibitory one and linearly related with the stimulus. Also for the static stimulation the amplitude of the response was significantly higher when the animal was tilted about the effective intermediate roll-pitch axis for all the 4 muscles. The presence of a maximal EMG response in the same modality for both static and dynamic stimulation indicates a similar spatial organization of those subgroups of ampullar and macular receptors projecting to the same eye muscle.

  5. FATIGUE ASSOCIATED EMG BEHAVIOR OF THE FIRST DORSAL INTEROSSEOUS AND ADDUCTOR POLLICIS MUSCLES IN DIFFERENT GROUPS OF SUBJECTS

    NARCIS (Netherlands)

    ZIJDEWIND, Inge; KERNELL, D

    We have studied the fatigue-associated behavior of surface EMG in two histochemically different muscles of the hand: fi rst dorsal interosseous (FDI) and adductor pollicis (AP; relatively more type I fibers in AP than in FDI). During a fatigue test evoked by electrical stimulation of the ulnar

  6. The use of EMG biofeedback for learning of selective activation of intra-muscular parts within the serratus anterior muscle

    DEFF Research Database (Denmark)

    Holtermann, A; Mork, P J; Andersen, L L

    2010-01-01

    Motor control and learning possibilities of scapular muscles are of clinical interest for restoring scapular muscle balance in patients with neck and shoulder disorders. The aim of the study was to investigate whether selective voluntary activation of intra-muscular parts within the serratus...... anterior can be learned with electromyographical (EMG) biofeedback, and whether the lower serratus anterior and the lower trapezius muscle comprise the lower scapula rotation force couple by synergistic activation. Nine healthy males practiced selective activation of intra-muscular parts within...... the serratus anterior with visual EMG biofeedback, while the activity of four parts of the serratus anterior and four parts of the trapezius muscle was recorded. One subject was able to selectively activate both the upper and the lower serratus anterior respectively. Moreover, three subjects managed...

  7. Influence of fatigue on hand muscle coordination and EMG-EMG coherence during three-digit grasping

    National Research Council Canada - National Science Library

    Danna-Dos Santos, Alessander; Poston, Brach; Jesunathadas, Mark; Bobich, Lisa R; Hamm, Thomas M; Santello, Marco

    2010-01-01

    .... While the modulation of neural drive to hand muscles as a function of force has been extensively studied, much less is known about the effects of fatigue on the coordination of simultaneously active hand muscles...

  8. EMGD-FE: an open source graphical user interface for estimating isometric muscle forces in the lower limb using an EMG-driven model

    Science.gov (United States)

    2014-01-01

    Background This paper describes the “EMG Driven Force Estimator (EMGD-FE)”, a Matlab® graphical user interface (GUI) application that estimates skeletal muscle forces from electromyography (EMG) signals. Muscle forces are obtained by numerically integrating a system of ordinary differential equations (ODEs) that simulates Hill-type muscle dynamics and that utilises EMG signals as input. In the current version, the GUI can estimate the forces of lower limb muscles executing isometric contractions. Muscles from other parts of the body can be tested as well, although no default values for model parameters are provided. To achieve accurate evaluations, EMG collection is performed simultaneously with torque measurement from a dynamometer. The computer application guides the user, step-by-step, to pre-process the raw EMG signals, create inputs for the muscle model, numerically integrate the ODEs and analyse the results. Results An example of the application’s functions is presented using the quadriceps femoris muscle. Individual muscle force estimations for the four components as well the knee isometric torque are shown. Conclusions The proposed GUI can estimate individual muscle forces from EMG signals of skeletal muscles. The estimation accuracy depends on several factors, including signal collection and modelling hypothesis issues. PMID:24708668

  9. EMGD-FE: an open source graphical user interface for estimating isometric muscle forces in the lower limb using an EMG-driven model.

    Science.gov (United States)

    Menegaldo, Luciano Luporini; de Oliveira, Liliam Fernandes; Minato, Kin K

    2014-04-04

    This paper describes the "EMG Driven Force Estimator (EMGD-FE)", a Matlab® graphical user interface (GUI) application that estimates skeletal muscle forces from electromyography (EMG) signals. Muscle forces are obtained by numerically integrating a system of ordinary differential equations (ODEs) that simulates Hill-type muscle dynamics and that utilises EMG signals as input. In the current version, the GUI can estimate the forces of lower limb muscles executing isometric contractions. Muscles from other parts of the body can be tested as well, although no default values for model parameters are provided. To achieve accurate evaluations, EMG collection is performed simultaneously with torque measurement from a dynamometer. The computer application guides the user, step-by-step, to pre-process the raw EMG signals, create inputs for the muscle model, numerically integrate the ODEs and analyse the results. An example of the application's functions is presented using the quadriceps femoris muscle. Individual muscle force estimations for the four components as well the knee isometric torque are shown. The proposed GUI can estimate individual muscle forces from EMG signals of skeletal muscles. The estimation accuracy depends on several factors, including signal collection and modelling hypothesis issues.

  10. Does a SLAP lesion affect shoulder muscle recruitment as measured by EMG activity during a rugby tackle?

    Directory of Open Access Journals (Sweden)

    Herrington Lee C

    2010-02-01

    Full Text Available Abstract Background The study objective was to assess the influence of a SLAP lesion on onset of EMG activity in shoulder muscles during a front on rugby football tackle within professional rugby players. Methods Mixed cross-sectional study evaluating between and within group differences in EMG onset times. Testing was carried out within the physiotherapy department of a university sports medicine clinic. The test group consisted of 7 players with clinically diagnosed SLAP lesions, later verified on arthroscopy. The reference group consisted of 15 uninjured and full time professional rugby players from within the same playing squad. Controlled tackles were performed against a tackle dummy. Onset of EMG activity was assessed from surface EMG of Pectorialis Major, Biceps Brachii, Latissimus Dorsi, Serratus Anterior and Infraspinatus muscles relative to time of impact. Analysis of differences in activation timing between muscles and limbs (injured versus non-injured side and non injured side versus matched reference group. Results Serratus Anterior was activated prior to all other muscles in all (P = 0.001-0.03 subjects. In the SLAP injured shoulder Biceps was activated later than in the non-injured side. Onset times of all muscles of the non-injured shoulder in the injured player were consistently earlier compared with the reference group. Whereas, within the injured shoulder, all muscle activation timings were later than in the reference group. Conclusions This study shows that in shoulders with a SLAP lesion there is a trend towards delay in activation time of Biceps and other muscles with the exception of an associated earlier onset of activation of Serratus anterior, possibly due to a coping strategy to protect glenohumeral stability and thoraco-scapular stability. This trend was not statistically significant in all cases

  11. Spatial EMG potential distribution pattern of vastus lateralis muscle during isometric knee extension in young and elderly men.

    Science.gov (United States)

    Watanabe, Kohei; Kouzaki, Motoki; Merletti, Roberto; Fujibayashi, Mami; Moritani, Toshio

    2012-02-01

    The aim of the present study was to compare spatial electromyographic (EMG) potential distribution during force production between elderly and young individuals using multi-channel surface EMG (SEMG). Thirteen elderly (72-79years) and 13 young (21-27years) healthy male volunteers performed ramp submaximal contraction during isometric knee extension from 0% to 65% of maximal voluntary contraction. During contraction, multi-channel EMG was recorded from the vastus lateralis muscle. To evaluate alteration in heterogeneity and pattern in spatial EMG potential distribution, coefficient of variation (CoV), modified entropy and correlation coefficients with initial torque level were calculated from multi-channel SEMG at 5% force increment. Increase in CoV and decrease in modified entropy of RMS with increase of exerted torque were significantly smaller in elderly group (pchannel SEMG pattern in elderly individual reflects neuromuscular activation strategy regulated predominantly by clustering of similar type of muscle fibers in aged muscle. Copyright © 2011 Elsevier Ltd. All rights reserved.

  12. Influence of Fatigue on Hand Muscle Coordination and EMG-EMG Coherence During Three-Digit Grasping

    OpenAIRE

    Danna-Dos Santos, Alessander; Poston, Brach; Jesunathadas, Mark; Bobich, Lisa R.; Hamm, Thomas M.; Santello, Marco

    2010-01-01

    Fingertip force control requires fine coordination of multiple hand muscles within and across the digits. While the modulation of neural drive to hand muscles as a function of force has been extensively studied, much less is known about the effects of fatigue on the coordination of simultaneously active hand muscles. We asked eight subjects to perform a fatiguing contraction by gripping a manipulandum with thumb, index, and middle fingers while matching an isometric target force (40% maximal ...

  13. EMG biofeedback used to reduce standing levels of paraspinal muscle tension in chronic low back pain.

    Science.gov (United States)

    Nouwen, A

    1983-12-01

    Twenty chronic low back pain (LBP) patients with relatively high standing paraspinal EMG levels (greater than 5 microV) were randomly assigned to 2 groups. One group (N = 10) received EMG biofeedback training to reduce standing paraspinal EMG levels, the other group (N = 10) served as a waiting list control group. Changes in perceived pain (duration X intensity) and paraspinal EMG in standing position were measured at a 3 week pretreatment baseline, during the 3 week treatment period, and at a 3 week post-treatment baseline. Compared to patients in the waiting list control group, those who received EMG biofeedback showed a significant decrease in standing paraspinal EMG from pretreatment to post-treatment baseline. However, no significant differences in reported pain were found during these periods. It is concluded that reduction of standing paraspinal EMG does not lead to reduction in pain.

  14. Relationship of EMG/SMG features and muscle strength level: an exploratory study on tibialis anterior muscles during plantar-flexion among hemiplegia patients.

    Science.gov (United States)

    Li, Huihui; Zhao, Guoru; Zhou, Yongjin; Chen, Xin; Ji, Zhen; Wang, Lei

    2014-01-27

    Improvement in muscle strength is an important aim for the rehabilitation of hemiplegia patients. Presently, the rehabilitation prescription depends on the evaluation results of muscle strength, which are routinely estimated by experienced physicians and therefore not finely quantitative. Widely-used quantification methods for disability, such as Barthel Index (BI) and motor component of Functional Independent Measure (M-FIM), yet have limitations in their application, since both of them differentiated disability better in lower than higher disability, and they are subjective and recorded in wide scales. In this paper, to explore finely quantitative measures for evaluation of muscle strength level (MSL), we start with the study on quantified electromyography (EMG) and sonomyography (SMG) features of tibialis anterior (TA) muscles among hemiplegia patients. 12 hemiplegia subjects volunteered to perform several sets of plantar-flexion movements in the study, and their EMG signals and SMG signals were recorded on TA independently to avoid interference. EMG data were filtered and then the root-mean-square (RMS) was computed. SMG signals, specifically speaking, the muscle thickness of TA, were manually measured by two experienced operators using ultrasonography. Reproducibility of the SMG assessment on TA between operators was evaluated by non-parametric test (independent sample T test). Possible relationship between muscle thickness changes (TC) of TA and muscle strength level of hemiplegia patients was estimated. Mean of EMG RMS between subjects is found linearly correlated with MSL (R2 = 0.903). And mean of TA muscle TC amplitudes is also linearly correlated with MSL among dysfunctional legs (R2 = 0.949). Moreover, rectified TC amplitudes (dysfunctional leg/ healthy leg, DLHL) and rectified EMG signals (DLHL) are found in linear correlation with MSL, with R2 = 0.756 and R2 = 0.676 respectively. Meanwhile, the preliminary results demonstrate that

  15. Relationship of EMG/SMG features and muscle strength level: an exploratory study on tibialis anterior muscles during plantar-flexion among hemiplegia patients

    Science.gov (United States)

    2014-01-01

    Background Improvement in muscle strength is an important aim for the rehabilitation of hemiplegia patients. Presently, the rehabilitation prescription depends on the evaluation results of muscle strength, which are routinely estimated by experienced physicians and therefore not finely quantitative. Widely-used quantification methods for disability, such as Barthel Index (BI) and motor component of Functional Independent Measure (M-FIM), yet have limitations in their application, since both of them differentiated disability better in lower than higher disability, and they are subjective and recorded in wide scales. In this paper, to explore finely quantitative measures for evaluation of muscle strength level (MSL), we start with the study on quantified electromyography (EMG) and sonomyography (SMG) features of tibialis anterior (TA) muscles among hemiplegia patients. Methods 12 hemiplegia subjects volunteered to perform several sets of plantar-flexion movements in the study, and their EMG signals and SMG signals were recorded on TA independently to avoid interference. EMG data were filtered and then the root-mean-square (RMS) was computed. SMG signals, specifically speaking, the muscle thickness of TA, were manually measured by two experienced operators using ultrasonography. Reproducibility of the SMG assessment on TA between operators was evaluated by non-parametric test (independent sample T test). Possible relationship between muscle thickness changes (TC) of TA and muscle strength level of hemiplegia patients was estimated. Results Mean of EMG RMS between subjects is found linearly correlated with MSL (R2 = 0.903). And mean of TA muscle TC amplitudes is also linearly correlated with MSL among dysfunctional legs (R2 = 0.949). Moreover, rectified TC amplitudes (dysfunctional leg/ healthy leg, DLHL) and rectified EMG signals (DLHL) are found in linear correlation with MSL, with R2 = 0.756 and R2 = 0.676 respectively. Meanwhile, the preliminary

  16. Training-related changes in the EMG-moment relationship during isometric contractions: Further evidence of improved control of muscle activation in strength-trained men?

    Science.gov (United States)

    Amarantini, David; Bru, Bertrand

    2015-08-01

    The possibility of using electromyography (EMG) to track muscle activity has raised the question of its relationship with the effort exerted by the muscles around the joints. However, the EMG-moment relationship is yet to be fully defined, and increasing knowledge of this topic could contribute to research in motor control and to the development of EMG-based algorithms and devices. With regards the training-related adaptations at the peripheral and central level, the present study investigated the effect of strength training on EMG-moment relationship. Our aim was to clarify its nature and gain further understanding of how morphological and neural factors may affect its form. The EMG-moment relationship was determined during knee flexion and extension isometric contractions performed by strength-trained male athletes and untrained male participants. The results showed that strength training induced linearity of the EMG-moment relationship concomitantly with enhanced maximum force production capacity and decreased co-activation of knee agonist-antagonist muscle pair. These results clarified discordant results regarding the linear or curved nature of the EMG-moment in isometric conditions and suggested that the remarkable linearity of the EMG-moment found in trained participants could indicate improved control of muscle activation. Copyright © 2015 Elsevier Ltd. All rights reserved.

  17. Evaluation of muscle force classification using shape analysis of the sEMG probability density function: a simulation study.

    Science.gov (United States)

    Ayachi, F S; Boudaoud, S; Marque, C

    2014-08-01

    In this work, we propose to classify, by simulation, the shape variability (or non-Gaussianity) of the surface electromyogram (sEMG) amplitude probability density function (PDF), according to contraction level, using high-order statistics (HOS) and a recent functional formalism, the core shape modeling (CSM). According to recent studies, based on simulated and/or experimental conditions, the sEMG PDF shape seems to be modified by many factors as: contraction level, fatigue state, muscle anatomy, used instrumentation, and also motor control parameters. For sensitivity evaluation against these several sources (physiological, instrumental, and neural control) of variability, a large-scale simulation (25 muscle anatomies, ten parameter configurations, three electrode arrangements) is performed, by using a recent sEMG-force model and parallel computing, to classify sEMG data from three contraction levels (20, 50, and 80% MVC). A shape clustering algorithm is then launched using five combinations of HOS parameters, the CSM method and compared to amplitude clustering with classical indicators [average rectified value (ARV) and root mean square (RMS)]. From the results screening, it appears that the CSM method obtains, using Laplacian electrode arrangement, the highest classification scores, after ARV and RMS approaches, and followed by one HOS combination. However, when some critical confounding parameters are changed, these scores decrease. These simulation results demonstrate that the shape screening of the sEMG amplitude PDF is a complex task which needs both efficient shape analysis methods and specific signal recording protocol to be properly used for tracking neural drive and muscle activation strategies with varying force contraction in complement to classical amplitude estimators.

  18. Quadriceps Muscles O2 Extraction and EMG Breakpoints during a Ramp Incremental Test

    Directory of Open Access Journals (Sweden)

    Danilo Iannetta

    2017-09-01

    Full Text Available Muscle deoxygenated breakpoint ([HHb]BP has been found to be associated with other indices of exercise tolerance in the vastus lateralis (VL muscle but not in the vastus medialis (VM and rectus femoris (RF.Purpose: To investigate whether the [HHb]BP occurs also in the VM and RF muscles and whether or not it is associated with other physiological indices of exercise tolerance, such as the EMG threshold (EMGt and the respiratory compensation point (RCP.Methods: Twelve young endurance trained participants performed maximal ramp incremental (RI cycling tests (25–30 W·min−1 increments. Muscle oxygen extraction and activity as well as ventilatory and gas exchange parameters were measured. After accounting for the mean response time, the oxygen uptake (V·O2 corresponding to the RCP, [HHb]BP, and the EMGt was determined.Results: Peak power output (POpeak was 359 ± 48 W. Maximal oxygen consumption (V·O2max was 3.87 ± 0.46 L·min−1. The V·O2 at the RCP was 3.39 ± 0.41 L·min−1. The V·O2 (L·min−1 corresponding to the [HHb]BP and EMGt were: 3.49 ± 0.46 and 3.40 ± 0.44; 3.44 ± 0.61 and 3.43 ± 0.49; 3.59 ± 0.52, and 3.48 ± 0.46 for VL, VM, and RF, respectively. Pearson's correlation between these thresholds ranged from 0.90 to 0.97 (P < 0.05. No difference was found for the absolute V·O2 and the normalized PO (% at which the thresholds occurred in all three muscles investigated (P > 0.05. Although in eight out of 12 participants, the [HHb]BP in the RF led to a steeper increase instead of leading to a plateau-like response as observed in the VL and VM, the V·O2 at the breakpoints still coincided with that at the RCP.Conclusions: This study demonstrated that local indices of exercise tolerance derived from different portions of the quadriceps are not different to the systemic index of the RCP.

  19. Muscle strength, resting muscle tone and EMG activation in untrained men: interaction effect of time of day and test order-related confounding factors.

    Science.gov (United States)

    Sedliak, M; Haverinen, M; Häkkinen, K

    2011-12-01

    This article was designed to study an interaction effect of time of day and test order-related confounding factors on daily variation in maximum muscle strength and power. Seventeen untrained men were randomized into four groups and measured at four time points (08:00 a.m., 12:00 a.m., 04:00 p.m. and 08:00 p.m.) throughout one or two days. Each groups started at different time of day in a counter-balanced order. Peak force and myoelectrical activity (EMG) of vastus medialis, vastus lateralis and biceps femoris muscles during bilateral isometric leg extension and power output during explosive dynamic leg extension was measured. Computerized muscle tonometer was used to assess resting muscle tone. Resting muscle tone did not change significantly regardless of time of day or test order. In contrast, time-of-day effect was found in force and EMG during isometric leg extension and in power output; all variables were significantly lower in the morning compared to the individual best performance/highest value achieved at any time point. In addition, the above variables were also affected by test order. Regardless of time of day, isometric force and EMG were typically highest during the first test session, while the dynamic power output gradually improved with test order. Daily variation in maximum voluntary strength and power performance could be detected despite the test order-related confounding factors.

  20. Muscle Activity Map Reconstruction from High Density Surface EMG Signals With Missing Channels Using Image Inpainting and Surface Reconstruction Methods.

    Science.gov (United States)

    Ghaderi, Parviz; Marateb, Hamid R

    2017-07-01

    The aim of this study was to reconstruct low-quality High-density surface EMG (HDsEMG) signals, recorded with 2-D electrode arrays, using image inpainting and surface reconstruction methods. It is common that some fraction of the electrodes may provide low-quality signals. We used variety of image inpainting methods, based on partial differential equations (PDEs), and surface reconstruction methods to reconstruct the time-averaged or instantaneous muscle activity maps of those outlier channels. Two novel reconstruction algorithms were also proposed. HDsEMG signals were recorded from the biceps femoris and brachial biceps muscles during low-to-moderate-level isometric contractions, and some of the channels (5-25%) were randomly marked as outliers. The root-mean-square error (RMSE) between the original and reconstructed maps was then calculated. Overall, the proposed Poisson and wave PDE outperformed the other methods (average RMSE 8.7 μVrms ± 6.1 μVrms and 7.5 μVrms ± 5.9 μVrms) for the time-averaged single-differential and monopolar map reconstruction, respectively. Biharmonic Spline, the discrete cosine transform, and the Poisson PDE outperformed the other methods for the instantaneous map reconstruction. The running time of the proposed Poisson and wave PDE methods, implemented using a Vectorization package, was 4.6 ± 5.7 ms and 0.6 ± 0.5 ms, respectively, for each signal epoch or time sample in each channel. The proposed reconstruction algorithms could be promising new tools for reconstructing muscle activity maps in real-time applications. Proper reconstruction methods could recover the information of low-quality recorded channels in HDsEMG signals.

  1. Comparison of algorithms to quantify muscle fatigue in upper limb muscles based on sEMG signals.

    Science.gov (United States)

    Kahl, Lorenz; Hofmann, Ulrich G

    2016-11-01

    This work compared the performance of six different fatigue detection algorithms quantifying muscle fatigue based on electromyographic signals. Surface electromyography (sEMG) was obtained by an experiment from upper arm contractions at three different load levels from twelve volunteers. Fatigue detection algorithms mean frequency (MNF), spectral moments ratio (SMR), the wavelet method WIRM1551, sample entropy (SampEn), fuzzy approximate entropy (fApEn) and recurrence quantification analysis (RQA%DET) were calculated. The resulting fatigue signals were compared considering the disturbances incorporated in fatiguing situations as well as according to the possibility to differentiate the load levels based on the fatigue signals. Furthermore we investigated the influence of the electrode locations on the fatigue detection quality and whether an optimized channel set is reasonable. The results of the MNF, SMR, WIRM1551 and fApEn algorithms fell close together. Due to the small amount of subjects in this study significant differences could not be found. In terms of disturbances the SMR algorithm showed a slight tendency to out-perform the others. Copyright © 2016 IPEM. Published by Elsevier Ltd. All rights reserved.

  2. The acute effects of local muscle vibration frequency on peak torque, rate of torque development, and EMG activity.

    Science.gov (United States)

    Pamukoff, Derek N; Ryan, Eric D; Blackburn, J Troy

    2014-12-01

    Vibratory stimuli enhance muscle activity and may be used for rehabilitation and performance enhancement. Efficacy of vibration varies with the frequency of stimulation, but the optimal frequency is unclear. The purpose of this study was to examine the effects of 30 Hz and 60 Hz local muscle vibration (LMV) on quadriceps function. Twenty healthy volunteers (age = 20.4 ± 1.4 years, mass = 68.1 ± 11.0 kg, height = 170.1 ± 8.8 cm, males = 9) participated. Isometric knee extensor peak torque (PT), rate of torque development (RTD), and electromyography (EMG) of the quadriceps were assessed followed by one of the three LMV treatments (30 Hz, 60 Hz, control) applied under voluntary contraction, and again immediately, 5, 15, and 30 min post-treatment in three counterbalanced sessions. Dependent variables were analyzed using condition by time repeated-measures ANOVA. The condition × time interaction was significant for EMG amplitude (p = 0.001), but not for PT (p=0.324) or RTD (p = 0.425). The increase in EMG amplitude following 30 Hz LMV was significantly greater than 60 Hz LMV and control. These findings suggest that 30 Hz LMV may elicit an improvement in quadriceps activation and could be used to treat quadriceps dysfunction resulting from knee pathologies. Copyright © 2014 Elsevier Ltd. All rights reserved.

  3. Differential effects of type of keyboard playing task and tempo on surface EMG amplitudes of forearm muscles

    Directory of Open Access Journals (Sweden)

    Hyun Ju eChong

    2015-09-01

    Full Text Available Despite increasing interest in keyboard playing as a strategy for repetitive finger exercises in fine motor skill development and hand rehabilitation, comparative analysis of task-specific finger movements relevant to keyboard playing has been less extensive. This study examined whether there were differences in surface EMG activity levels of forearm muscles associated with different keyboard playing tasks. Results demonstrated higher muscle activity with sequential keyboard playing in a random pattern compared to individuated playing or sequential playing in a successive pattern. Also, the speed of finger movements was found as a factor that affect muscle activity levels, demonstrating that faster tempo elicited significantly greater muscle activity than self-paced tempo. The results inform our understanding of the type of finger movements involved in different types of keyboard playing at different tempi so as to consider the efficacy and fatigue level of keyboard playing as an intervention for amateur pianists or individuals with impaired fine motor skills.

  4. Three-Dimensional Model of a Muscle and Simulation of its Surface EMG

    National Research Council Canada - National Science Library

    Schnetzer, M

    2001-01-01

    ...) and a simulation of its surface EMG. The simulations are part of a larger model including in addition the input system to the motoneuronal pool, the motoneuronal pool itself and the force generating mechanism...

  5. An isometric muscle force estimation framework based on a high-density surface EMG array and an NMF algorithm

    Science.gov (United States)

    Huang, Chengjun; Chen, Xiang; Cao, Shuai; Qiu, Bensheng; Zhang, Xu

    2017-08-01

    Objective. To realize accurate muscle force estimation, a novel framework is proposed in this paper which can extract the input of the prediction model from the appropriate activation area of the skeletal muscle. Approach. Surface electromyographic (sEMG) signals from the biceps brachii muscle during isometric elbow flexion were collected with a high-density (HD) electrode grid (128 channels) and the external force at three contraction levels was measured at the wrist synchronously. The sEMG envelope matrix was factorized into a matrix of basis vectors with each column representing an activation pattern and a matrix of time-varying coefficients by a nonnegative matrix factorization (NMF) algorithm. The activation pattern with the highest activation intensity, which was defined as the sum of the absolute values of the time-varying coefficient curve, was considered as the major activation pattern, and its channels with high weighting factors were selected to extract the input activation signal of a force estimation model based on the polynomial fitting technique. Main results. Compared with conventional methods using the whole channels of the grid, the proposed method could significantly improve the quality of force estimation and reduce the electrode number. Significance. The proposed method provides a way to find proper electrode placement for force estimation, which can be further employed in muscle heterogeneity analysis, myoelectric prostheses and the control of exoskeleton devices.

  6. Surface EMG during the Push-up plus Exercise on a Stable Support or Swiss Ball: Scapular Stabilizer Muscle Exercise.

    Science.gov (United States)

    Seo, Sung-Hwa; Jeon, In-Ho; Cho, Yong-Ho; Lee, Hyun-Gi; Hwang, Yoon-Tae; Jang, Jee-Hun

    2013-07-01

    [Purpose] Scapular stabilizer strengthening exercise is crucial for shoulder rehabilitation. The purpose of this study was to compare two types of push-up plus exercises, on a stable and unstable bases of support, using surface electromyography (EMG), to suggest an effective shoulder rehabilitation program. [Subjects and Methods] Ten healthy men volunteered for this study. All volunteers performed two sets of push-up plus exercise (standard push up and knee push up) on stable and unstable bases of support. The muscle activities of five important scapular stabilizer muscles (upper trapezius, middle trapezius, lower trapezius, serratus anterior, latissimus dorsi) were recorded during the exercise. [Results] The upper trapezius showed greater mean electric activation amplitude in the scapular retraction posture than in the scapular protraction posture, and the serratus anterior showed greater mean electric activation amplitude in the scapular protraction posture than in the scapular retraction posture. The root-mean-square normalized EMG values of the muscles were greater during the exercise performed on the unstable support than those on the stable support. [Conclusion] The standard push-up plus exercise on an unstable base of support helps to increase muscle activity, especially those of the upper/middle trapezius and serratus anterior.

  7. Changes in EMG Activities of Upper Arm Muscles and in Shoulder Joint Angles in Post-stroke Patients

    Directory of Open Access Journals (Sweden)

    Rositsa Raikova

    2016-09-01

    Full Text Available The aim of the paper is to compare the electromyographic signals (EMGs and the joint angles of the affected upper limb muscles of stroke survivors to those of their non-affected limb as well as to those of the dominant and the non-dominant limbs of healthy volunteers. Twenty five volunteers, ten post-stroke survivors and fifteen healthy subjects as control group, participated in the experiments. EMGs of muscles of the upper limbs and two angles in the shoulder joint were registered and processed during three static and two dynamic tasks. The results showed a big variability of all investigated parameters (mean and median frequencies, ranges of motions, maximal normalized EMGs both for the patients and for the healthy subjects, for right and for left hand. This makes difficult a deduction of definitive conclusions about the changes in motor control of the upper limbs due to stroke. Moreover, natural differences in motor control exist for dominant and non-dominant limb. On the whole, the power-frequency analysis and the relevant statistical analysis indicated that the muscles of the affected limb had lower median frequencies than those of the healthy limb. Examination of full elbow flexions in the sagittal plane showed that the range of the motion in the shoulder joint of both limbs of the patients increased when compared to the healthy subjects and that this increase was larger for the affected limb. The post-stroke survivors used more of their muscle power although no increased co-contraction was observed.

  8. Musculoskeletal modeling of human lower limb during normal walking, one-legged forward hopping and side jumping: Comparison of measured EMG and predicted muscle activity patterns.

    Science.gov (United States)

    Wibawa, A D; Verdonschot, N; Halbertsma, J P K; Burgerhof, J G M; Diercks, R L; Verkerke, G J

    2016-11-07

    This study focused on comparing muscle activities predicted by the Musculoskeletal Modeling System with EMG from ten healthy subjects who performed normal walking, one-legged forward hopping and side jumping. Eight EMG electrodes measured the activity of eight right leg muscles. Specific thresholds per muscle were applied on the EMG prior comparison. These thresholds were determined by equalizing the duration of EMG to AMS muscle activity. Three graph variables, number of onsets, offsets and hills were used to quantify the level of agreement by using Cohen׳s kappa analysis. The Pearson correlation coefficient was also calculated as a result comparison. Overall, visual inspection showed comparable activity patterns. However, when quantifying them some differences became apparent. The mean level of agreement of all tests was EMG pattern. Those differences can be attributed to inevitable modeling limitation within the AMS framework like miscalculating the knee net moment, absence of co-contraction, simplified knee joint. Moreover, the delay between EMG and AMS has a clear effect on the comparison and this delay is obviously missing in the model. Despite those differences, this study can serve as a baseline measurement allowing progress in scientific work in order to reduce uncertainties with the aim to generate more reliable and robust musculoskeletal models in a valid manner. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. An algorithm for detecting EMG onset/offset in trunk muscles during a reaction- stabilization test.

    Science.gov (United States)

    Jubany, Júlia; Angulo-Barroso, Rosa

    2016-04-27

    Most of the EMG analysis algorithms developed to date don't detect the whole sequence of rhythmic and subtle changes that take place during the process of trunk stabilization. Indeed, the few recent methods that are capable of assessing these important EMG characteristics are highly complex and not accessible in most applied clinic contexts. To validate and disseminate a software program suitable for detecting multiple and relatively small EMG bursts during a trunk stabilization response. Ninety EMG recordings randomly selected from 50 individuals (24 with chronic low back pain) were analysed by our algorithm based on means and standard deviations and an experienced examiner (as a gold standard). Concordance, sensitivity, specificity, positive predictive value and negative predictive value were considered to analyse reliability. Results showed a high degree of concordance between the two methods (87.2%), high sensitivity and specificity rates (79.5 and 89.2%), a moderate-low positive predicted value (66.9%) and a high negative predicted value (94.4%). The program provided is flexible and useful to detect EMG activity. The selected parameters of the program were able to detect onset/offset EMG bursts and were valid for the purpose of this study with a small tendency to over-detect bursts.

  10. Assessment of work-related muscle strain by using surface EMG during test contractions interposed between work periods of simulateted mushroom picking

    DEFF Research Database (Denmark)

    Ohashi, Jun-Ya; Blangsted, Anne Katrine; Nielsen, Pernille Kofoed

    2010-01-01

    minutes in the rest periods. EMGs were recorded from the trapezius, infraspinatus, deltoid, and erector spinae muscles. The amplitude of EMG (AEMG) and mean power frequency (MPF) of EMG were calculated. Each TC was divided equally into three parts. Ratings of perceived exertion (RPE) in the neck, shoulder......Surface electromyograms(EMG) during test contractions (TCs) were studied to assess the muscle strain in simulated mushroom picking. Additionally, the duration of the TC for the effective assessment was investigated. Nine female subjects performed standardized shoulder abduction and a stooped...... posture for one minute as TCs. Each experiment consisted of a 60-min rest, three work periods (W1-W3), a 30-min rest, and two work periods (W4 and W5) separated by a 30-min rest period. The duration of each work period was about 20 min. A total of 18 TCs was performed between the work periods and every 10...

  11. Design, Development and Testing of a Low-Cost sEMG System and Its Use in Recording Muscle Activity in Human Gait

    Directory of Open Access Journals (Sweden)

    Tamara Grujic Supuk

    2014-05-01

    Full Text Available Surface electromyography (sEMG is an important measurement technique used in biomechanical, rehabilitation and sport environments. In this article the design, development and testing of a low-cost wearable sEMG system are described. The hardware architecture consists of a two-cascade small-sized bioamplifier with a total gain of 2,000 and band-pass of 3 to 500 Hz. The sampling frequency of the system is 1,000 Hz. Since real measured EMG signals are usually corrupted by various types of noises (motion artifacts, white noise and electromagnetic noise present at 50 Hz and higher harmonics, we have tested several denoising techniques, both on artificial and measured EMG signals. Results showed that a wavelet—based technique implementing Daubechies5 wavelet and soft sqtwolog thresholding is the most appropriate for EMG signals denoising. To test the system performance, EMG activities of six dominant muscles of ten healthy subjects during gait were measured (gluteus maximus, biceps femoris, sartorius, rectus femoris, tibialis anterior and medial gastrocnemius. The obtained EMG envelopes presented against the duration of gait cycle were compared favourably with the EMG data available in the literature, suggesting that the proposed system is suitable for a wide range of applications in biomechanics.

  12. Design, Development and Testing of a Low-Cost sEMG System and Its Use in Recording Muscle Activity in Human Gait

    Science.gov (United States)

    Supuk, Tamara Grujic; Skelin, Ana Kuzmanic; Cic, Maja

    2014-01-01

    Surface electromyography (sEMG) is an important measurement technique used in biomechanical, rehabilitation and sport environments. In this article the design, development and testing of a low-cost wearable sEMG system are described. The hardware architecture consists of a two-cascade small-sized bioamplifier with a total gain of 2,000 and band-pass of 3 to 500 Hz. The sampling frequency of the system is 1,000 Hz. Since real measured EMG signals are usually corrupted by various types of noises (motion artifacts, white noise and electromagnetic noise present at 50 Hz and higher harmonics), we have tested several denoising techniques, both on artificial and measured EMG signals. Results showed that a wavelet—based technique implementing Daubechies5 wavelet and soft sqtwolog thresholding is the most appropriate for EMG signals denoising. To test the system performance, EMG activities of six dominant muscles of ten healthy subjects during gait were measured (gluteus maximus, biceps femoris, sartorius, rectus femoris, tibialis anterior and medial gastrocnemius). The obtained EMG envelopes presented against the duration of gait cycle were compared favourably with the EMG data available in the literature, suggesting that the proposed system is suitable for a wide range of applications in biomechanics. PMID:24811078

  13. The relationship of extraneous movements to lumbar paraspinal muscle activity: implications for EMG biofeedback training applications to low back pain patients.

    Science.gov (United States)

    Wolf, S L; Wolf, L B; Segal, R L

    1989-03-01

    Within recent years clinicians and researchers have applied paraspinal EMG biofeedback procedures during static and dynamic movement retraining of chronic low back pain patients. Most of these applications make use of surface electromyography, an approach complicated by the fact that the erector spinae muscles are deeply situated. This descriptive study reveals that extraneous movements, such as neck flexion and pelvic rotation, can elicit profound activity from percutaneously placed EMG electrodes while little change is seen at the skin surface. The implications of these observations for the use of EMG feedback to remediate low back pain are discussed.

  14. Spatial distribution of surface EMG on trapezius and lumbar muscles of violin and cello players in single note playing.

    Science.gov (United States)

    Afsharipour, Babak; Petracca, Francesco; Gasparini, Mauro; Merletti, Roberto

    2016-12-01

    Musicians activate their muscles in different patterns, depending on their posture, the instrument being played, and their experience level. Bipolar surface electrodes have been used in the past to monitor such activity, but this method is highly sensitive to the location of the electrode pair. In this work, the spatial distribution of surface EMG (sEMG) of the right trapezius and right and left erector spinae muscles were studied in 16 violin players and 11 cello players. Musicians played their instrument one string at a time in sitting position with/without backrest support. A 64 sEMG electrode (16×4) grid, 10mm inter-electrode distance (IED), was placed over the middle and lower trapezius (MT and LT) of the bowing arm. Two 16×2 electrode grids (IED=10mm) were placed on the left and right erector spinae muscles. Subjects played each of the four strings of the instrument either in large (1bow/s) or detaché tip/tail (8bows/s) bowing in two sessions (two days). In each of two days, measurements were repeated after half an hour of exercise to see the effect of exercise on the muscle activity and signal stability. A "muscle activity index" (MAI) was defined as the spatial average of the segmented active region of the RMS map. Spatial maps were automatically segmented using the watershed algorithm and thresholding. Results showed that, for violin players, sliding the bow upward from the tip toward the tail results in a higher MAI for the trapezius muscle than a downward bow. On the contrary, in cello players, higher MAI is produced in the tail to tip movement. For both instruments, an increasing MAI in the trapezius was observed as the string position became increasingly lateral, from string 1 (most medial) toward string 4 (most lateral). Half an hour of performance did not cause significant differences between the signal quality and the MAI values measured before and after the exercise. The MAI of the left and right erector spinae was smaller in the case of

  15. Electromyography (EMG)

    Science.gov (United States)

    Tests and Procedures Electromyography (EMG) By Mayo Clinic Staff Electromyography (EMG) is a diagnostic procedure to assess the health of ... Woodward Lips Patient Education Center. About your electromyography (EMG) examination. Rochester, Minn.: Mayo Foundation for Medical Education ... . Mayo ...

  16. Individual-specific muscle maximum force estimation using ultrasound for ankle joint torque prediction using an EMG-driven Hill-type model.

    Science.gov (United States)

    de Oliveira, Liliam Fernandes; Menegaldo, Luciano Luporini

    2010-10-19

    EMG-driven models can be used to estimate muscle force in biomechanical systems. Collected and processed EMG readings are used as the input of a dynamic system, which is integrated numerically. This approach requires the definition of a reasonably large set of parameters. Some of these vary widely among subjects, and slight inaccuracies in such parameters can lead to large model output errors. One of these parameters is the maximum voluntary contraction force (F(om)). This paper proposes an approach to find F(om) by estimating muscle physiological cross-sectional area (PCSA) using ultrasound (US), which is multiplied by a realistic value of maximum muscle specific tension. Ultrasound is used to measure muscle thickness, which allows for the determination of muscle volume through regression equations. Soleus, gastrocnemius medialis and gastrocnemius lateralis PCSAs are estimated using published volume proportions among leg muscles, which also requires measurements of muscle fiber length and pennation angle by US. F(om) obtained by this approach and from data widely cited in the literature was used to comparatively test a Hill-type EMG-driven model of the ankle joint. The model uses 3 EMGs (Soleus, gastrocnemius medialis and gastrocnemius lateralis) as inputs with joint torque as the output. The EMG signals were obtained in a series of experiments carried out with 8 adult male subjects, who performed an isometric contraction protocol consisting of 10s step contractions at 20% and 60% of the maximum voluntary contraction level. Isometric torque was simultaneously collected using a dynamometer. A statistically significant reduction in the root mean square error was observed when US-obtained F(om) was used, as compared to F(om) from the literature. Copyright © 2010 Elsevier Ltd. All rights reserved.

  17. Reliability of the diaphragmatic compound muscle action potential evoked by cervical magnetic stimulation and recorded via chest wall surface EMG.

    Science.gov (United States)

    Welch, Joseph F; Mildren, Robyn L; Zaback, Martin; Archiza, Bruno; Allen, Grayson P; Sheel, A William

    2017-09-01

    Stimulation of the phrenic nerve via cervical magnetic stimulation (CMS) elicits a compound muscle action potential (CMAP) that allows for assessment of diaphragm activation. The reliability of CMS to evoke the CMAP recorded by chest wall surface EMG has yet to be comprehensively examined. CMS was performed on healthy young males (n=10) and females (n=10). Surface EMG electrodes were placed on the right and left hemi-diaphragm between the 6-8th intercostal spaces. CMAPs were analysed for: latency, duration, peak-to-peak amplitude, and area. Reliability within and between experimental sessions was assessed using intraclass correlation coefficients (ICC). Bilateral (right-left) and sex-based (male-female) comparisons were also made (independent samples t-test). All CMAP characteristics demonstrated high reproducibility within (ICCs>0.96) and between (ICCs>0.89) experimental sessions. No statistically significant bilateral or sex-based differences were found (p>0.05). CMS is a reliable and non-invasive method to evaluate phrenic nerve conduction. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Test-retest reliability of muscle fiber conduction velocity and fractal dimension of surface EMG during isometric contractions.

    Science.gov (United States)

    Beretta-Piccoli, Matteo; D'Antona, Giuseppe; Zampella, Cristian; Barbero, Marco; Clijsen, Ron; Cescon, Corrado

    2017-04-01

    The aim of this study was to determine the test-retest reliability of muscle fiber conduction velocity (CV) and fractal dimension (FD) obtained from multichannel surface electromyographic (sEMG) recordings. Forty healthy recreationally active subjects (20 men and 20 women) performed two elbow flexions on two trials with a 1 week interval. The first was a 20% maximal voluntary contraction (MVC) of 120 s, and the second at 60% MVC held until exhaustion. sEMG signals were detected from the biceps brachii, using bi-dimensional arrays. Initial values and slope of CV and FD were used for the reliability analysis. The intraclass correlation coefficient (ICC) values for the isometric contraction at 20% MVC were (-0.09) and 0.67 for CV and FD respectively; whereas the ICC values at 60% MVC were 0.78 and 0.82 for CV and FD respectively. The Bland Altman plots for the two isometric contractions showed a mean difference close to zero, with no evident outliers between the repeated measurements: at 20% MVC 0.001 53 for FD and  -0.0277 for CV, and at 60% MVC 0.006 66 for FD and 0.009 07 for CV. Overall, our findings suggest that during isometric fatiguing contractions, CV and FD slopes are reliable variables, with potential application in clinical populations.

  19. Evoked EMG versus muscle torque during fatiguing functional electrical stimulation-evoked muscle contractions and short-term recovery in individuals with spinal cord injury.

    Science.gov (United States)

    Estigoni, Eduardo H; Fornusek, Che; Hamzaid, Nur Azah; Hasnan, Nazirah; Smith, Richard M; Davis, Glen M

    2014-12-03

    This study investigated whether the relationship between muscle torque and m-waves remained constant after short recovery periods, between repeated intervals of isometric muscle contractions induced by functional electrical stimulation (FES). Eight subjects with spinal cord injury (SCI) were recruited for the study. All subjects had their quadriceps muscles group stimulated during three sessions of isometric contractions separated by 5 min of recovery. The evoked-electromyographic (eEMG) signals, as well as the produced torque, were synchronously acquired during the contractions and during short FES bursts applied during the recovery intervals. All analysed m-wave variables changed progressively throughout the three contractions, even though the same muscle torque was generated. The peak to peak amplitude (PtpA), and the m-wave area (Area) were significantly increased, while the time between the stimulus artefact and the positive peak (PosT) were substantially reduced when the muscles became fatigued. In addition, all m-wave variables recovered faster and to a greater extent than did torque after the recovery intervals. We concluded that rapid recovery intervals between FES-evoked exercise sessions can radically interfere in the use of m-waves as a proxy for torque estimation in individuals with SCI. This needs to be further investigated, in addition to seeking a better understanding of the mechanisms of muscle fatigue and recovery.

  20. Evoked EMG versus Muscle Torque during Fatiguing Functional Electrical Stimulation-Evoked Muscle Contractions and Short-Term Recovery in Individuals with Spinal Cord Injury

    Directory of Open Access Journals (Sweden)

    Eduardo H. Estigoni

    2014-12-01

    Full Text Available This study investigated whether the relationship between muscle torque and m-waves remained constant after short recovery periods, between repeated intervals of isometric muscle contractions induced by functional electrical stimulation (FES. Eight subjects with spinal cord injury (SCI were recruited for the study. All subjects had their quadriceps muscles group stimulated during three sessions of isometric contractions separated by 5 min of recovery. The evoked-electromyographic (eEMG signals, as well as the produced torque, were synchronously acquired during the contractions and during short FES bursts applied during the recovery intervals. All analysed m-wave variables changed progressively throughout the three contractions, even though the same muscle torque was generated. The peak to peak amplitude (PtpA, and the m-wave area (Area were significantly increased, while the time between the stimulus artefact and the positive peak (PosT were substantially reduced when the muscles became fatigued. In addition, all m-wave variables recovered faster and to a greater extent than did torque after the recovery intervals. We concluded that rapid recovery intervals between FES-evoked exercise sessions can radically interfere in the use of m-waves as a proxy for torque estimation in individuals with SCI. This needs to be further investigated, in addition to seeking a better understanding of the mechanisms of muscle fatigue and recovery.

  1. Analysis of Muscle Contraction on Pottery Manufacturing Process Using Electromyography (EMG)

    Science.gov (United States)

    Soewardi, Hartomo; Azka Rahmayani, Amalia

    2016-01-01

    One of the most common problems in pottery manufacturing process is musculoskeletal disorders on workers. This disorder was caused by uncomfortable posture where the workers sit on the floor with one leg was folded and another was twisted for long duration. Back, waist, buttock, and right knee frequently experience the disorders. The objective of this research is to investigate the muscle contraction at such body part of workers in manufacturing process of pottery. Electromyography is used to investigate the muscle contraction based on the median frequency signal. Focus measurements is conducted on four muscles types. They are lower interscapular muscle on the right and left side, dorsal lumbar muscle, and lateral hamstring muscle. Statistical analysis is conducted to test differences of muscle contraction between female and male. The result of this research showed that the muscle which reached the highest contraction is dorsal lumbar muscle with the average of median frequency is 51,84 Hz. Then followed by lower interscapular muscle on the left side with the average of median frequency is 31,30 hz, lower interscapular muscle on the right side average of median frequency is 31,24 Hz, and lateral hamstring muscle average of median frequency is 21,77 Hz. Based on the statistic analysis result, there were no differences between male and female on left and right lower interscapular muscle and dorsal lumbar muscle but there were differences on lateral hamstring muscle with the significance level is 5%. Besides that, there were differences for all combination muscle types with the level of significance is 5%.

  2. EMG Activity in the Abdominal Muscles and the Kinematics of the Lumbar Spine during Unilateral Upper-limb Resistance Exercises under Stable and Unstable Conditions.

    Science.gov (United States)

    Kang, Min-Hyeok; Kim, Man-Sig

    2014-06-01

    [Purpose] We investigated the effects of unstable conditions on the electromyographic (EMG) activity of the rectus abdominis (RA) and the transverse abdominis-internal oblique (TrA-IO) muscles, and lumbar kinematics during unilateral upper-limb resistance exercises using elastic tubing bands. [Subjects] Twelve healthy males were recruited. [Methods] The subjects performed isometric left shoulder abduction using an elastic tubing band in a sitting position on a chair, and on a Swiss ball. During this exercise, EMG activities of the RA and TrA-IO were recorded using a wireless EMG system, and a three-dimensional motion analysis system monitored lumbar kinematics. Differences in EMG activities of the RA and TrA-IO, the ratio of TrA-IO to RA activity, and lumbar kinematics were compared between the stable and unstable conditions using the paired t-test. [Results] Under the unstable condition, the EMG activities of both muscles were significantly greater than that under the stable condition; however the ratio of TrA-IO to RA activity did not significantly differ between the conditions. The lumbar angle significantly differed only in the coronal plane. [Conclusions] These findings indicate that trunk posture should be considered when performing exercises under unstable conditions.

  3. [Data collection of signals in the multi-channel sEMG system of masticatory muscles and development and preliminary clinical application of an analytic system].

    Science.gov (United States)

    Du, Hongliang; Li, Xin; Li, Shan; Zhang, Rui; Song, Rong; Li, Lan; Wang, Wei; Kang, Hong

    2014-02-01

    The aim of this study was to design a simple, economic, with high Common Mode Rejection Ratio (CMRR), preamplifier and multi-channel masticatory muscle surface electromyography (sEMG) signal acquisition system assisting to diagnose temporomandibular disorders (TMD). We used the USB interface technology in the EMG data with the aid of the windows to operate system and graphical interface. Eight patients with TMD and eight controls were analyzed separately using this system. In this system, we analyzed sEMG by an optional combination of time domain, frequency domain, time-frequency, several spectral analysis, wavelets and other special algorithms under multi-parameter. Multi-channel sEMG System of Masticatory Muscles is a simple, economic system. It has high sensitivity and specificity. The sEMG signals were changed in patients with TMD. The system would pave the way for diagnosis TMD and help us to assess the treatment effect. A novel and objective method is provided for diagnosis and treatment of oral-maxillofacial disease and functional reconstruction.

  4. Reliability study of tibialis posterior and selected leg muscle EMG and multi-segment foot kinematics in rheumatoid arthritis associated pes planovalgus.

    Science.gov (United States)

    Barn, Ruth; Rafferty, Daniel; Turner, Deborah E; Woodburn, James

    2012-07-01

    To determine within- and between-day reliability characteristics of electromyographic (EMG) activity patterns of selected lower leg muscles and kinematic variables in patients with rheumatoid arthritis (RA) and pes planovalgus. Five patients with RA underwent gait analysis barefoot and shod on two occasions 1 week apart. Fine-wire (tibialis posterior [TP]) and surface EMG for selected muscles and 3D kinematics using a multi-segmented foot model was undertaken barefoot and shod. Reliability of pre-determined variables including EMG activity patterns and inter-segment kinematics were analysed using coefficients of multiple correlation, intraclass correlation coefficients (ICC) and the standard error of the measurement (SEM). Muscle activation patterns within- and between-day ranged from fair-to-good to excellent in both conditions. Discrete temporal and amplitude variables were highly variable across all muscle groups in both conditions but particularly poor for TP and peroneus longus. SEMs ranged from 1% to 9% of stance and 4% to 27% of maximum voluntary contraction; in most cases the 95% confidence interval crossed zero. Excellent within-day reliability was found for the inter-segment kinematics in both conditions. Between-day reliability ranged from fair-to-good to excellent for kinematic variables and all ICCs were excellent; the SEM ranged from 0.60° to 1.99°. Multi-segmented foot kinematics can be reliably measured in RA patients with pes planovalgus. Serial measurement of discrete variables for TP and other selected leg muscles via EMG is not supported from the findings in this cohort of RA patients. Caution should be exercised when EMG measurements are considered to study disease progression or intervention effects. Copyright © 2012 Elsevier B.V. All rights reserved.

  5. Cauda equina repair in the rat: part 1. Stimulus-evoked EMG for identifying spinal nerves innervating intrinsic tail muscles.

    Science.gov (United States)

    Blaskiewicz, Don J; Smirnov, Igor; Cisu, Tudor; DeRuisseau, Lara R; Stelzner, Dennis J; Calancie, Blair

    2009-08-01

    Cauda equina injuries may produce severe leg and pelvic floor dysfunction, for which no effective treatments exist. We are developing a rat cauda equina injury model to allow nerve root identification and surgical repair. One possible difficulty in implementing any repair strategy after trauma in humans involves the correct identification of proximal and distal ends of nerve roots separated by the injury. Two series of studies were carried out. In Series 1, we electrically stimulated segmental contributors to the dorsal and ventral caudales nerves in order to characterize the recruitment patterns of muscles controlling rat tail movements. In Series 2, we attempted to identify individual nerve roots forming the cauda equina by both level of origin and function (i.e., dorsal or ventral), based solely upon the recruitment patterns in response to electrical stimulation. For Series 1 studies, electrical stimulation of the segmental contributors showed that all nerve roots-from the sixth lumbar to the first coccygeal-contributed to recruitment of muscles found at the base of the tail. Intrinsic tail muscles lying more distally in the tail showed a more root-specific pattern of innervation. For Series 2, the rate of successful identification of an unknown nerve root as being ventral was very high (>95%), and only somewhat lower (approximately 80%) for dorsal roots. Correctly identifying the level of origin of that root was more difficult, but for ventral roots this rate still exceeded 90%. Using the rat cauda equina model, we have shown that stimulus-evoked EMG can be used to identify ventral nerve roots innervating tail muscles with a high degree of accuracy. These findings support the feasibility of using this conceptual approach for identifying and repairing damaged human cauda equina nerve roots based on stimulus-evoked recruitment of muscles in the leg and pelvic floor.

  6. EMG-normalised kinase activation during exercise is higher in human gastrocnemius compared to soleus muscle

    DEFF Research Database (Denmark)

    Jensen, Thomas Elbenhardt; Leutert, Robin; Rasmussen, Søren T

    2012-01-01

    In mice, certain proteins show a highly confined expression in specific muscle groups. Also, resting and exercise/contraction-induced phosphorylation responses are higher in rat skeletal muscle with low mitochondrial content compared to muscles with high mitochondrial content, possibly related...... activating soleus and gastrocnemius in a comparable dynamic work-pattern. Hexokinase II and GLUT4 were 46-59% and 26-38% higher (p...

  7. Shoulder muscle EMG activity during push up variations on and off a Swiss ball.

    Science.gov (United States)

    Lehman, Gregory J; MacMillan, Brandon; MacIntyre, Ian; Chivers, Michael; Fluter, Mark

    2006-06-09

    Surface instability is a common addition to traditional rehabilitation and strength exercises with the aim of increasing muscle activity, increasing exercise difficulty and improving joint proprioception. The aim of the current study was to determine if performing upper body closed kinetic chain exercises on a labile surface (Swiss ball) influences myoelectric amplitude when compared with a stable surface. Thirteen males were recruited from a convenience sample of college students. Surface electromyograms were recorded from the triceps, pectoralis major, latissimus dorsi, rectus abdominis and external oblique while performing push up exercises with the feet or hands placed on a bench and separately on a Swiss ball. A push up plus exercise was also evaluated with hands on the support surface. Not all muscles responded with an increase in muscle activity. The pectoralis major muscle was not influenced by surface stability. The triceps and rectus abdominis muscles showed increases in muscle activity only when the hands were on the unstable surface. The external oblique muscle was only influenced by surface stability during the performance of the push up plus exercise. No muscle showed a change in activation level when the legs were supported by the Swiss ball instead of the bench. Muscle activity can be influenced by the addition of surface instability however an increase in muscle activity does not influence all muscles in all conditions. The relationship between the participant's center of mass, the location of the unstable surface and the body part contacting the Swiss ball may be important factors in determining the muscle activation changes following changes in surface stability.

  8. Changes in EMG activity in the upper trapezius muscle due to local vibration exposure

    NARCIS (Netherlands)

    Astrom, Charlotte; Lindkvist, Markus; Burstrom, Lage; Sundelin, Gunnevi; Karlsson, J. Stefan

    Exposure to vibration is suggested as a risk factor for developing neck and shoulder disorders in working life. Mechanical vibration applied to a muscle belly or a tendon can elicit a reflex muscle contraction, also called tonic vibration reflex, but the mechanisms behind how vibration could cause

  9. Stress Testing Recovery EMG for Evaluation of Biofeedback and Progressive Muscle Relaxation Training Effects.

    Science.gov (United States)

    Sime, Wesley E.; DeGood, Douglas E.

    The purpose of this investigation was to assess biofeedback (BF) and progressive muscle relaxation (PMR) and placebo-control training by means of a post-training transfer test. The subjects for the research were 30 women. Initial tests consisted of measuring the electromyographic response of the frontalis muscle of the forehead to stress. After…

  10. The Effect of Varying Biting Position on Relative Jaw Muscle EMG activity

    Science.gov (United States)

    1988-09-01

    theme, i.e. that the masticatory system functions to produce bite force in a way that minimizes joint reaction forces. 35 REFERENCES Ahigren, J. (1967...electromyographic study. J. Oral. Rehab. 1, 19- 27. Baron, P. and Debussy, T. (1979) A biomechanical functional analysis of the masticatory muscles in man...during clenching and chewing. Arch. Oral. Biol. 31, 245-253. Wood, W. W. (1987) A review of masticatory muscle function . J. Prosthet. Dent. 57, 222-232

  11. EMG analysis of shoulder muscle fatigue during resisted isometric shoulder elevation.

    Science.gov (United States)

    Minning, Stephen; Eliot, Colin A; Uhl, Tim L; Malone, Terry R

    2007-04-01

    The purpose of this study was to determine if a difference existed in the rate of fatigue of select shoulder muscles during isometric shoulder elevation and if the measured rate of fatigue was consistent from day to day. Shoulder muscle fatigue has been associated with alterations in joint mechanics and possibly contributes to shoulder dysfunction. While research exists, there is limited information on an objective and reliable measure of shoulder fatigue. Sixteen asymptomatic subjects were evaluated. The subjects held a weight equivalent to 60% of his/her Maximum Voluntary Isometric Contraction (MVIC) while elevating in the scapular plane. Surface electrodes were applied to collect electromyographic activity from the upper trapezius, middle deltoid, serratus anterior, and lower trapezius muscles while the arm was held at 90 degrees elevation. Data collection ceased when the subject was no longer able to maintain 90 degrees of elevation. The subject then rested and a second trial performed. One week later, the two-trial procedure was repeated. A significant interaction of trial x day x muscle was found for the rate of fatigue. Post hoc analysis revealed that the rate of fatigue of the middle deltoid was significantly greater than the other muscles tested. The intraday reliability was good for all muscles but interday reliability was poor except for the middle deltoid. This study suggests that the middle deltoid appears to fatigue faster than the other shoulder muscles tested at the selected level of shoulder elevation. This should be considered in designing a rehabilitation program to develop a sequence that does not overly fatigue the middle deltoid.

  12. Changes in EMG activity in the upper trapezius muscle due to local vibration exposure.

    Science.gov (United States)

    Aström, Charlotte; Lindkvist, Markus; Burström, Lage; Sundelin, Gunnevi; Karlsson, J Stefan

    2009-06-01

    Exposure to vibration is suggested as a risk factor for developing neck and shoulder disorders in working life. Mechanical vibration applied to a muscle belly or a tendon can elicit a reflex muscle contraction, also called tonic vibration reflex, but the mechanisms behind how vibration could cause musculoskeletal disorders has not yet been described. One suggestion has been that the vibration causes muscular fatigue. This study investigates whether vibration exposure changes the development of muscular fatigue in the trapezius muscle. Thirty-seven volunteers (men and women) performed a sub-maximal isometric shoulder elevation for 3 min. This was repeated four times, two times with induced vibration and two times without. Muscle activity was measured before and after each 3-min period to look at changes in the electromyography parameters. The result showed a significantly smaller mean frequency decrease when performing the shoulder elevation with vibration (-2.51 Hz) compared to without vibration (-4.04 Hz). There was also a slightly higher increase in the root mean square when exposed to vibration (5.7% of maximal voluntary contraction) compared to without (3.8% of maximal voluntary contraction); however, this was not statistically significant. The results of the present study indicate that short-time exposure to vibration has no negative acute effects on the fatiguing of upper trapezius muscle.

  13. Specificity of surface-EMG on the intrinsic lumbar back muscles

    NARCIS (Netherlands)

    Vink, P.; Daanen, H. A M; Verbout, A.J.

    1989-01-01

    The cross-correlation coefficient functions (CCCFs) between twelve bipolar surface electrodes, placed symmetrically on the intrinsic lumbar back muscles (ILBM) were computed in order to estimate the amount of cross-talk. It was found that the CCCF values were mainly influenced by the distance

  14. Simultaneous 31P NMR spectroscopy and EMG in exercising and recovering human skeletal muscle: technical aspects

    DEFF Research Database (Denmark)

    Vestergaard-Poulsen, P; Thomsen, C; Sinkjaer, T

    1994-01-01

    The bioenergetics of human skeletal muscle can be studied by 31P NMR spectroscopy (31P-MRS) and by surface electromyography (SEMG). Simultaneous 31P-MRS and SEMG permit accurate and noninvasive studies of the correlation between metabolic and electrical changes in exercising and recovering human ...

  15. Features interference EMG leg extensor muscles of skilled players in the context of the special exercises

    Directory of Open Access Journals (Sweden)

    Sirenko P.A.

    2013-06-01

    Full Text Available The article considers the problems of improvement of physical training of skilled players. The main instrumental method of the research is electromyography. The aim of the research is determination of the optimal angle of the provisions of legs on her hips for the appearance of a maximum of bioelectric activity of the muscles of the front panel hips in exercise unbending legs sitting on the mechanical simulator. In the course of research we have worked for electromyography 10 players of FC Metalist at the age of 19 – 30 years during the five-second of the submaximum contraction of these muscles as: musculus rectus femoris, musculus vastus medialis, musculus vastus lateralis. The results of the analysis of segments of electromyography allowed to make a conclusion, that we investigated the provisions of the angle of 140 degrees has the lowest preconditions for the appearance of muscle strength. We have obtained data testify to the fact that the angle of 90 degrees is the position of the greatest preconditions for the appearance of muscle strength.

  16. EMG-Driven Forward-Dynamic Estimation of Muscle Force and Joint Moment about Multiple Degrees of Freedom in the Human Lower Extremity

    Science.gov (United States)

    Sartori, Massimo; Reggiani, Monica; Farina, Dario; Lloyd, David G.

    2012-01-01

    This work examined if currently available electromyography (EMG) driven models, that are calibrated to satisfy joint moments about one single degree of freedom (DOF), could provide the same musculotendon unit (MTU) force solution, when driven by the same input data, but calibrated about a different DOF. We then developed a novel and comprehensive EMG-driven model of the human lower extremity that used EMG signals from 16 muscle groups to drive 34 MTUs and satisfy the resulting joint moments simultaneously produced about four DOFs during different motor tasks. This also led to the development of a calibration procedure that allowed identifying a set of subject-specific parameters that ensured physiological behavior for the 34 MTUs. Results showed that currently available single-DOF models did not provide the same unique MTU force solution for the same input data. On the other hand, the MTU force solution predicted by our proposed multi-DOF model satisfied joint moments about multiple DOFs without loss of accuracy compared to single-DOF models corresponding to each of the four DOFs. The predicted MTU force solution was (1) a function of experimentally measured EMGs, (2) the result of physiological MTU excitation, (3) reflected different MTU contraction strategies associated to different motor tasks, (4) coordinated a greater number of MTUs with respect to currently available single-DOF models, and (5) was not specific to an individual DOF dynamics. Therefore, our proposed methodology has the potential of producing a more dynamically consistent and generalizable MTU force solution than was possible using single-DOF EMG-driven models. This will help better address the important scientific questions previously approached using single-DOF EMG-driven modeling. Furthermore, it might have applications in the development of human-machine interfaces for assistive devices. PMID:23300725

  17. The effect of C5 and C6 spinal manipulative therapy on the alpha motorneuron excitability of the musculocutaneous nerve in the biceps brachii muscle measured using EMG

    OpenAIRE

    2008-01-01

    M. Tech. Chiro. The purpose of this study was to determine the effect that C5 and C6 spinal manipulative therapy had on alpha motorneuron excitability of the musculocutaneous nerve in the biceps brachii muscle. Readings were recorded using Electromyography (EMG). Eighty asymptomatic subjects participated in this study. The subjects selected had to be between 18 and 35 years of age, having experienced no cervical pain, discomfort or pathology. The subjects had to present with a C5 or C6 joi...

  18. Use of antagonist muscle EMG in the assessment of neuromuscular health of the low back

    OpenAIRE

    Lee, Nakyung; Kang, Hwayeong; Shin, Gwanseob

    2015-01-01

    Background Non-specific low back pain (LBP) has been one of the most frequently occurring musculoskeletal problems. Impairment in the mechanical stability of the lumbar spine has been known to lower the safety margin of the spine musculature and can result in the occurrence of pain symptoms of the low back area. Previously, changes in spinal stability have been identified by investigating recruitment patterns of low back and abdominal muscles in laboratory experiments with controlled postures...

  19. Waterproofing EMG Instrumentation.

    Science.gov (United States)

    Benfield, Rebecca D; Newton, Edward R; Hortobágyi, Tibor

    2007-01-01

    While still experimental, measurement of external uterine electromyographic (EMG) activity is a more sensitive and noninvasive method for measuring uterine contractility in human labor than the methods currently used in clinical practice. Hydrotherapy is purported to improve contractility in labor, yet there have been no reports of abdominal uterine EMG activity measured during immersion. To test telemetric EMG equipment and different waterproofing techniques under dry and immersed conditions, the authors recorded surface EMG activity from the abdominal muscles of 11 healthy, nonpregnant women, 22 to 51 years of age. After attaching one pair of electrodes to the skin on either side of the umbilicus and applying the waterproofing material, the authors tested the signal by asking participants to perform a short series of leg lifts while seated in a chair to evoke abdominal muscle contractions. They were then immersed to the chest in a hydrotherapy tub while performing two to three leg lifts over 60 s every 5 min for 60 min with 20 lb of weight suspended from their ankles to counteract the buoyancy effect of water. EMG activity was continuously recorded. They then repeated the dry-measures sequence. While waterproofing remained intact, EMG signals were essentially unchanged between dry and wet conditions. Of the 11 waterproofing applications tested, 10 failed at some point. In the data from the successful application, EMG signals in both channels exhibited stable baselines throughout and an absence of low-frequency artifact. The development of this technique allows for the recording of external uterine EMG activity during hydrotherapy. The authors have begun using it to investigate the effects of hydrotherapy on uterine contractility during human labor.

  20. Evaluation of Head Orientation and Neck Muscle EMG Signals as Command Inputs to a Human-Computer Interface for Individuals with High Tetraplegia

    Science.gov (United States)

    Williams, Matthew R.; Kirsch, Robert F.

    2013-01-01

    We investigated the performance of three user interfaces for restoration of cursor control in individuals with tetraplegia: head orientation, EMG from face and neck muscles, and a standard computer mouse (for comparison). Subjects engaged in a 2D, center-out, Fitts’ Law style task and performance was evaluated using several measures. Overall, head orientation commanded motion resembled mouse commanded cursor motion (smooth, accurate movements to all targets), although with somewhat lower performance. EMG commanded movements exhibited a higher average speed, but other performance measures were lower, particularly for diagonal targets. Compared to head orientation, EMG as a cursor command source was less accurate, was more affected by target direction and was more prone to overshoot the target. In particular, EMG commands for diagonal targets were more sequential, moving first in one direction and then the other rather than moving simultaneous in the two directions. While the relative performance of each user interface differs, each has specific advantages depending on the application. PMID:18990652

  1. Normalizing EMG to Background Muscle Activation Masks Medication-Induced Reductions in Reflex Amplitudes in Parkinsonian Rigidity.

    Science.gov (United States)

    Powell, Douglas; Muthumani, Anburaj; Xia, Rui-Ping

    2017-02-01

    Exaggerated reflex responses to passive stretch and shortening contribute to parkinsonian rigidity. Studies have reported medication-induced reductions in rigidity in the absence of attenuated reflex magnitudes. The purpose of this study was to determine if normalization procedures mask medication-induced reductions in reflex responses in Parkinson's disease. Twelve participants with PD performed passive wrist flexion and extension movements after a 12-hour withdrawal from dopaminergic medication and 60 minutes after medication was administered. EMG was recorded from wrist flexors and extensors. Raw EMG signals were conditioned and normalized to mean background EMG amplitudes collected 100 ms prior to the onset of passive movement by division and by subtraction. Raw EMG amplitudes were significantly reduced. No medication-related reductions were observed during passive flexion or extension when EMG amplitudes were normalized by division. When EMG amplitudes were normalized by subtraction, significant reductions were observed following administration of dopaminergic medication during flexion and extension. Dopaminergic medication was associated with significant reductions in rigidity work scores and significant increases in moment-angle slope plots. These findings demonstrate that EMG normalization techniques may hinder data interpretation in studies of altered reflex responses in individuals with Parkinson's disease following the administration of dopaminergic medication.

  2. Abdominal muscle EMG-activity during bridge exercises on stable and unstable surfaces.

    Science.gov (United States)

    Czaprowski, Dariusz; Afeltowicz, Anna; Gębicka, Anna; Pawłowska, Paulina; Kędra, Agnieszka; Barrios, Carlos; Hadała, Michał

    2014-08-01

    To assess abdominal muscles (AM) activity during prone, side, and supine bridge on stable and unstable surfaces (BOSU, Swiss Ball). Prospective comparison study. Research laboratory. Thirty-three healthy volunteers from a university population. Surface electromyography of the rectus abdominis (RA), the external oblique (EO) and the internal oblique with the transversus abdominis (IO-TA). The AM exhibited the highest activity during prone bridge on a Swiss Ball (RA, EO, IO-TA 44.7 ± 19.2, 54.7 ± 22.9, 36.8 ± 18.6 in % of MVC, respectively). The lowest activity was observed during supine bridge on a stable surface and a BOSU (under 5.0). The lowest ratio analyzed on the basis of the relation of EO and IO-TA activity to RA was obtained during prone bridge on the Swiss Ball (1.4 ± 0.7 for EO, 0.9 ± 0.5 for IO-TA). The highest ratio was obtained during prone bridge on stable surface and supine bridges. The highest level of activity in the abdominal muscles is achieved during prone bridge on a Swiss Ball. However, this exercise provided the lowest activity of the EO and IO-TA in relation to RA. It is essential to conduct further studies verifying the usefulness of using Swiss Ball during core stability training. Copyright © 2013 Elsevier Ltd. All rights reserved.

  3. Quantitative differences among EMG activities of muscles innervated by subpopulations of hypoglossal and upper spinal motoneurons during non-REM sleep - REM sleep transitions: a window on neural processes in the sleeping brain.

    Science.gov (United States)

    Rukhadze, I; Kamani, H; Kubin, L

    2011-12-01

    In the rat, a species widely used to study the neural mechanisms of sleep and motor control, lingual electromyographic activity (EMG) is minimal during non-rapid eye movement (non-REM) sleep and then phasic twitches gradually increase after the onset of REM sleep. To better characterize the central neural processes underlying this pattern, we quantified EMG of muscles innervated by distinct subpopulations of hypoglossal motoneurons and nuchal (N) EMG during transitions from non-REM sleep to REM sleep. In 8 chronically instrumented rats, we recorded cortical EEG, EMG at sites near the base of the tongue where genioglossal and intrinsic muscle fibers predominate (GG-I), EMG of the geniohyoid (GH) muscle, and N EMG. Sleep-wake states were identified and EMGs quantified relative to their mean levels in wakefulness in successive 10 s epochs. During non-REM sleep, the average EMG levels differed among the three muscles, with the order being N>GH>GG-I. During REM sleep, due to different magnitudes of phasic twitches, the order was reversed to GG-I>GH>N. GG-I and GH exhibited a gradual increase of twitching that peaked at 70-120 s after the onset of REM sleep and then declined if the REM sleep episode lasted longer. We propose that a common phasic excitatory generator impinges on motoneuron pools that innervate different muscles, but twitching magnitudes are different due to different levels of tonic motoneuronal hyperpolarization. We also propose that REM sleep episodes of average durations are terminated by intense activity of the central generator of phasic events, whereas long REM sleep episodes end as a result of a gradual waning of the tonic disfacilitatory and inhibitory processes.

  4. Assessment of force and fatigue in isometric contractions of the upper trapezius muscle by surface EMG signal and perceived exertion scale.

    Science.gov (United States)

    Troiano, Amedeo; Naddeo, Francesco; Sosso, Erik; Camarota, Gianfranco; Merletti, Roberto; Mesin, Luca

    2008-08-01

    Quantifying muscle force and fatigue is important in designing ergonomic work stations, in planning appropriate work-rest patterns, and in preventing/assessing the progress of disorders. In 14 subjects (seven males, seven females), muscle force and fatigue were estimated by subjective perception (based on Borg scale CR10) and objective indexes extracted from surface electromyogram (EMG). The experimental protocol consisted of an isometric task selective for the upper trapezius muscle at different force levels (10-80% of maximal voluntary contraction--MVC, in steps of 10%MVC) and one fatiguing contraction (constant force level at 50%MVC until exhaustion). Surface EMG signals were detected by a two-dimensional (2D) array of electrodes placed half way between C7 and the acromion. The following variables were calculated from EMG signals: muscle fibre conduction velocity (CV), root mean square value (RMS), mean frequency of the power spectrum (MNF), fractal dimension (FD), and entropy. All detected signals were also used to build topographical maps of RMS. Both subjective and objective indications of force and fatigue can provide information on exerted force and endurance time (ET). In particular, Borg ratings, RMS, and entropy were significantly related to force, and the rate of change of CV, MNF, FD, and Borg ratings were predictive of the endurance time. Moreover, significant differences were found in Borg ratings between males and females. The correlation coefficient of pairs of topographical maps of RMS was high (of the order of 0.8). This reflects a characteristic spatial-temporal recruitment of upper trapezius motor units that is not affected by force levels or fatigue.

  5. Mandibular movements at maximum mouth opening and EMG activity of masticatory and neck muscles in patients rehabilitated after a mandibular condyle fracture.

    Science.gov (United States)

    Sforza, Chiarella; Tartaglia, Gianluca M; Lovecchio, Nicola; Ugolini, Alessandro; Monteverdi, Riccardo; Giannì, Aldo Bruno; Ferrario, Virgilio F

    2009-09-01

    To assess rotation and translation movements of the mandible at maximum mouth opening in a group of patients successfully rehabilitated after condylar fractures. Using a three-dimensional motion analyser, free movements of mouth opening were recorded in nine patients, and divided into their rotation and gliding components. Surface electromyography (EMG) of the masticatory and sternocleidomastoid (SCM) muscles was performed during maximum voluntary teeth clenching (MVC). Data were compared with those collected in healthy adults. At maximum mouth opening, the total displacement of the mandibular interincisor point was 86% of reference value (p>0.05, Student's t test), with a reduced vertical displacement (84% of reference value, p=0.012). Percentage mandibular rotation was significantly larger in patients (82%) than in reference subjects (77%, p=0.005). During MVC, patients had more asymmetric EMG potentials (p=0.018), with greater mandibular torque (pmandibular movement, the rotation/translation components of mouth opening were modified. The overall EMG performance score could be used to predict the characteristics of mandibular motion.

  6. The recovery of repeated-sprint exercise is associated with PCr resynthesis, while muscle pH and EMG amplitude remain depressed.

    Directory of Open Access Journals (Sweden)

    Alberto Mendez-Villanueva

    Full Text Available The physiological equivalents of power output maintenance and recovery during repeated-sprint exercise (RSE remain to be fully elucidated. In an attempt to improve our understanding of the determinants of RSE performance we therefore aimed to determine its recovery following exhaustive exercise (which affected intramuscular and neural factors concomitantly with those of intramuscular concentrations of adenosine triphosphate [ATP], phosphocreatine [PCr] and pH values and electromyography (EMG activity (a proxy for net motor unit activity changes. Eight young men performed 10, 6-s all-out sprints on a cycle ergometer, interspersed with 30 s of recovery, followed, after 6 min of passive recovery, by five 6-s sprints, again interspersed by 30 s of passive recovery. Biopsies of the vastus lateralis were obtained at rest, immediately after the first 10 sprints and after 6 min of recovery. EMG activity of the vastus lateralis was obtained from surface electrodes throughout exercise. Total work (TW, [ATP], [PCr], pH and EMG amplitude decreased significantly throughout the first ten sprints (P<0.05. After 6 min of recovery, TW during sprint 11 recovered to 86.3±7.7% of sprint 1. ATP and PCr were resynthesized to 92.6±6.0% and 85.3±10.3% of the resting value, respectively, but muscle pH and EMG amplitude remained depressed. PCr resynthesis was correlated with TW done in sprint 11 (r = 0.79, P<0.05 and TW done during sprints 11 to 15 (r = 0.67, P<0.05. There was a ∼2-fold greater decrease in the TW/EMG ratio in the last five sprints (sprint 11 to 15 than in the first five sprints (sprint 1 to 5 resulting in a disproportionate decrease in mechanical power (i.e., TW in relation to EMG. Thus, we conclude that the inability to produce power output during repeated sprints is mostly mediated by intramuscular fatigue signals probably related with the control of PCr metabolism.

  7. A comparison of the electromyographic activity (EMG of the muscles during the release phase of javelin throwing in disabled male world and paralympic champions

    Directory of Open Access Journals (Sweden)

    Heydar Sadeghi

    2016-09-01

    Full Text Available Background : The purpose of this study was to recognize the performance of the pectoralis major, anterior deltoid, and triceps muscles of the disabled male world and paralympic championsby the EMG. Materials and Methods: The electrical activity of the pectoralis major, anterior deltoid, and triceps muscles of 24 disabled Iranian male world and paralympic throwers in sitting and standing positions was recorded by a surface electromyographic device. To determine the significant differences of the sitting and standing classes, the statistics techniques of the One Way ANOVA and the independent t- test at the 0.05 sinificant level were administered to the recorded data. Results: The activity (amplitude of pectoralis major and anterior deltoid muscles of the participants differed significantly in the sitting classes. Also, the activity of triceps muscles in the standing classes and that of pectoralis major muscles of the sitting and standing classes while the amplitude of triceps muscles of sitting classes, pectoralis major and anterior deltoid muscles of the standing classes, and anterior deltoid and triceps muscles of both sitting and standing classes was not significantly different. (p<0.05. Conclusion: The means of all the variables in the sitting classes were more than those in the standing classes. The highest amplitude belonged to the anterior deltoid, pectoralis major and triceps muscles of the sitting classes, respectively. This is due to the disabled throwers’ paralysis in the sitting position compared with that of the throwers in standing positions. The comparison of the amplitude recorded by surface electromyography of the disabled throwers’ muscles in all classes showed that the pectoralis major, anterior deltoid, and triceps muscles have major roles in the disabled male world and paralympic champions’ throwing events.

  8. Inferring Muscle-Tendon Unit Power from Ankle Joint Power during the Push-Off Phase of Human Walking: Insights from a Multiarticular EMG-Driven Model.

    Directory of Open Access Journals (Sweden)

    Eric C Honert

    Full Text Available Inverse dynamics joint kinetics are often used to infer contributions from underlying groups of muscle-tendon units (MTUs. However, such interpretations are confounded by multiarticular (multi-joint musculature, which can cause inverse dynamics to over- or under-estimate net MTU power. Misestimation of MTU power could lead to incorrect scientific conclusions, or to empirical estimates that misguide musculoskeletal simulations, assistive device designs, or clinical interventions. The objective of this study was to investigate the degree to which ankle joint power overestimates net plantarflexor MTU power during the Push-off phase of walking, due to the behavior of the flexor digitorum and hallucis longus (FDHL-multiarticular MTUs crossing the ankle and metatarsophalangeal (toe joints.We performed a gait analysis study on six healthy participants, recording ground reaction forces, kinematics, and electromyography (EMG. Empirical data were input into an EMG-driven musculoskeletal model to estimate ankle power. This model enabled us to parse contributions from mono- and multi-articular MTUs, and required only one scaling and one time delay factor for each subject and speed, which were solved for based on empirical data. Net plantarflexing MTU power was computed by the model and quantitatively compared to inverse dynamics ankle power.The EMG-driven model was able to reproduce inverse dynamics ankle power across a range of gait speeds (R2 ≥ 0.97, while also providing MTU-specific power estimates. We found that FDHL dynamics caused ankle power to slightly overestimate net plantarflexor MTU power, but only by ~2-7%.During Push-off, FDHL MTU dynamics do not substantially confound the inference of net plantarflexor MTU power from inverse dynamics ankle power. However, other methodological limitations may cause inverse dynamics to overestimate net MTU power; for instance, due to rigid-body foot assumptions. Moving forward, the EMG-driven modeling

  9. The slow component of O(2) uptake is not accompanied by changes in muscle EMG during repeated bouts of heavy exercise in humans.

    Science.gov (United States)

    Scheuermann, B W; Hoelting, B D; Noble, M L; Barstow, T J

    2001-02-15

    1. We hypothesized that either the recruitment of additional muscle motor units and/or the progressive recruitment of less efficient fast-twitch muscle fibres was the predominant contributor to the additional oxygen uptake (VO2) observed during heavy exercise. Using surface electromyographic (EMG) techniques, we compared the VO2 response with the integrated EMG (iEMG) and mean power frequency (MPF) response of the vastus lateralis with the VO2 response during repeated bouts of moderate (below the lactate threshold, LT) intensity cycle ergometer exercise. 2. Seven male subjects (age 29 +/- 7 years, mean +/- S.D.) performed three transitions to a work rate (WR) corresponding to 90 % LT and two transitions to a work rate that would elicit a VO2 corresponding to 50 % of the difference between peak VO2 and the LT (i.e. Delta50 %, > LT1 and > LT2). 3. The VO2 slow component was significantly reduced by prior heavy intensity exercise (> LT1, 410 +/- 196 ml min(-1); > LT2, 230 +/- 191 ml min-1). The time constant (tau), amplitude (A) and gain (DeltaVO2/DeltaWR) of the primary VO2 response (phase II) were not affected by prior heavy exercise when a three-component, exponential model was used to describe the V2 response. 4. Integrated EMG and MPF remained relatively constant and at the same level throughout both > LT1 and > LT2 exercise and therefore were not associated with the VO2 slow component. 5. These data are consistent with the view that the increased O2 cost (i.e. VO2 slow component) associated with performing heavy exercise is coupled with a progressive increase in ATP requirements of the already recruited motor units rather than to changes in the recruitment pattern of slow versus fast-twitch motor units. Further, the lack of speeding of the kinetics of the primary VO2 component with prior heavy exercise, thought to represent the initial muscle VO2 response, are inconsistent with O2 delivery being the limiting factor in V > O2 kinetics during heavy exercise.

  10. Novel Methods for Surface EMG Analysis and Exploration Based on Multi-Modal Gaussian Mixture Models

    National Research Council Canada - National Science Library

    Vögele, Anna Magdalena; Zsoldos, Rebeka R; Krüger, Björn; Licka, Theresia

    2016-01-01

    .... It is based on fitting Gaussian mixture models (GMMs) to surface EMG data (sEMG). This approach enables researchers/users to isolate parts of the overall muscle activation within locomotion EMG data...

  11. Effects of 4-Week Intensive Active-Resistive Training with an EMG-Based Exoskeleton Robot on Muscle Strength in Older People: A Pilot Study

    Directory of Open Access Journals (Sweden)

    Jongsang Son

    2016-01-01

    Full Text Available This study aims to investigate the idea that an active-resistive training with an EMG-based exoskeleton robot could be beneficial to muscle strength and antagonist muscle cocontraction control after 4-week intensive elbow flexion/extension training. Three older people over 65 years participated the training for an hour per session and completed total 20 sessions during four weeks. Outcome measures were chosen as the maximum joint torque and cocontraction ratio between the biceps/triceps brachii muscles at pre-/post-training. The Wilcoxon signed-ranks test was performed to evaluate paired difference for the outcome measures. As a result, there was no significant difference in the maximum flexion or extension torque at pre- and post-training. However, the cocontraction ratio of the triceps brachii muscle as the antagonist was significantly decreased by 9.8% after the 4-week intensive training. The active-resistive training with the exoskeleton robot in the older people yielded a promising result, showing significant changes in the antagonist muscle cocontraction.

  12. Early corticospinal tract damage in prodromal SCA2 revealed by EEG-EMG and EMG-EMG coherence.

    Science.gov (United States)

    Velázquez-Pérez, Luis; Tünnerhoff, Johannes; Rodríguez-Labrada, Roberto; Torres-Vega, Reidenis; Ruiz-Gonzalez, Yusely; Belardinelli, Paolo; Medrano-Montero, Jacqueline; Canales-Ochoa, Nalia; González-Zaldivar, Yanetza; Vazquez-Mojena, Yaimeé; Auburger, Georg; Ziemann, Ulf

    2017-12-01

    Clinical data suggest early involvement of the corticospinal tract (CST) in spinocerebellar ataxia type 2 (SCA2). Here we tested if early CST degeneration can be detected in prodromal SCA2 mutation carriers by electrophysiological markers of CST integrity. CST integrity was tested in 15 prodromal SCA2 mutation carriers, 19 SCA2 patients and 25 age-matched healthy controls, using corticomuscular (EEG-EMG) and intermuscular (EMG-EMG) coherence measures in upper and lower limb muscles. Significant reductions of EEG-EMG and EMG-EMG coherences were observed in the SCA2 patients, and to a similar extent in the prodromal SCA2 mutation carriers. In prodromal SCA2, EEG-EMG and EMG-EMG coherences correlated with the predicted time to ataxia onset. Findings indicate early CST neurodegeneration in SCA2. EEG-EMG and EMG-EMG coherence may serve as biomarkers of early CST neurodegeneration in prodromal SCA2 mutation carriers. Findings are important for developing preclinical disease markers in the context of currently emerging disease-modifying therapies of neurodegenerative disorders. Copyright © 2017 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.

  13. The Location of Peak Upper Trapezius Muscle Activity During Submaximal Contractions is not Associated With the Location of Myofascial Trigger Points: New Insights Revealed by High-density Surface EMG.

    Science.gov (United States)

    Barbero, Marco; Falla, Deborah; Mafodda, Luca; Cescon, Corrado; Gatti, Roberto

    2016-12-01

    To apply topographical mapping of the electromyography (EMG) amplitude recorded from the upper trapezius muscle to evaluate the distribution of activity and the location of peak activity during a shoulder elevation task in participants with and without myofascial pain and myofascial trigger points (MTrP) and compare this location with the site of the MTrP. Thirteen participants with myofascial pain and MTrP in the upper trapezius muscle and 12 asymptomatic individuals participated. High-density surface EMG was recorded from the upper trapezius muscle using a matrix of 64 surface electrodes aligned with an anatomic landmark system (ALS). Each participant performed a shoulder elevation task consisting of a series of 30 s ramped contractions to 15% or 60% of their maximal voluntary contraction (MVC) force. Topographical maps of the EMG average rectified value were computed and the peak EMG amplitude during the ramped contractions was identified and its location determined with respect to the ALS. The location of the MTrP was also determined relative to the ALS and Spearman correlation coefficients were used to examine the relationship between MTrP and peak EMG amplitude location. The location of the peak EMG amplitude was significantly (PEMG amplitude during the ramped contractions at either force level (15%: rs=0.039, P=0.9; 60%: rs=-0.087, P=0.778). People with myofascial pain and MTrP displayed a caudal shift of the distribution of upper trapezius muscle activity compared with asymptomatic individuals during a submaximal shoulder elevation task. For the first time, we show that the location of peak muscle activity is not associated with the location of the MTrP.

  14. EMG-biofeedback assisted pelvic floor muscle training is an effective therapy of stress urinary or mixed incontinence: a 7-year experience with 390 patients.

    Science.gov (United States)

    Dannecker, Christian; Wolf, Veronika; Raab, Renate; Hepp, Hermann; Anthuber, Christoph

    2005-12-01

    The aim of the study was to determine the short- and long-term efficacy of an intensive and EMG-biofeedback-assisted pelvic floor muscle training (PFMT) program as a therapy of female stress or mixed urinary incontinence. All women with stress or mixed urinary incontinence treated in the pelvic floor reeducation program at our clinic between September 1996 and March 2003 were included. EMG-biofeedback assisted PFMT was performed by specially trained therapists (one registered nurse and one midwife). Electric stimulation preceded PFMT if the pelvic floor muscle contractions were considered too weak for active training (Oxford < 2). Examinations included among others: conventional urodynamic studies prior to therapy, a stress provocation test (cough test), and determination of maximal pelvic floor muscle strength (Oxford-grading and electric EMG-potential). A retrospective chart review was performed. A questionnaire was administered for long-term follow-up. Four hundred and thirty four women attended our PFR-program in this 7-year period. All 390 women with stress (80%) or mixed (20%) urinary incontinence were evaluated. Mean age: 52 years. Mean duration of incontinence: 6.7 years. Two hundred and sixty three women completed the training (group 1, average number of training sessions: 8.7), 127 patients ended therapy prematurely (group 2, average number of training sessions: 4.1). Short-term results at the end of the PFR-program are available for group 1. There was a statistically significant improvement of the stress provocation test (cough test). The data before the therapy was 141x SUI degrees III (60%); 50x SUI degrees II (21%), 24x SUI degrees I (10%), 20x SUI degrees 0 (9%) as opposed to after the therapy 9x SUI degrees III (5%), 34x SUI degrees II (19%), 48x SUI degrees I (26%), 91x SUI degrees 0 (50%). There was a significant increase in the Oxford-score by 1.2 points (2.9-4.1; P<0.001). Self-reported improvement of incontinence symptoms was 95%. The electric

  15. Plantarflexor muscle function in healthy and chronic Achilles tendon pain subjects evaluated by the use of EMG and PET imaging

    DEFF Research Database (Denmark)

    Masood, Tahir; Kalliokoski, Kari; Bojsen-Møller, Jens

    2014-01-01

    BACKGROUND: Achilles tendon pathologies may alter the coordinative strategies of synergistic calf muscles. We hypothesized that both surface electromyography and positron emission tomography would reveal differences between symptomatic and asymptomatic legs in Achilles tendinopathy patients and b...

  16. Myoelectric manifestation of muscle fatigue in repetitive work detected by means of miniaturized sEMG sensors.

    Science.gov (United States)

    Ranavolo, Alberto; Chini, Giorgia; Silvetti, Alessio; Mari, Silvia; Serrao, Mariano; Draicchio, Francesco

    2017-09-25

    Upper limb work-related musculoskeletal disorders have a 12-month prevalence ranging from 12 to 41% worldwide and can be partly caused by handling low loads at high frequency. The association between the myoelectric manifestation of elbow flexor muscle fatigue and occupational physical demand has never been investigated. It was hypothesized that an elbow flexor muscle fatigue index could be a valid risk indicator in handling low loads at high frequency. This study aims to measure the myoelectric manifestation of muscle fatigue of the three elbow flexor muscles during the execution of the work tasks in different risk conditions. Fifteen right-handed healthy adults were screened using a movement analysis laboratory consisting of optoelectronic, dynamometer and surface electromyographic systems. The main result indicates that the fatigue index calculated from the brachioradialis is sensitive to the interaction among risk classes, session and gender, and above all it is sensitive to the risk classes.

  17. Training-induced changes in muscle CSA, muscle strength, EMG, and rate of force development in elderly subjects after long-term unilateral disuse

    DEFF Research Database (Denmark)

    Suetta, Charlotte; Aagaard, Per; Rosted, Anna

    2004-01-01

    The ability to develop muscle force rapidly may be a very important factor to prevent a fall and to perform other tasks of daily life. However, information is still lacking on the range of training-induced neuromuscular adaptations in elderly humans recovering from a period of disuse. Therefore......, the present study examined the effect of three types of training regimes after unilateral prolonged disuse and subsequent hip-replacement surgery on maximal muscle strength, rapid muscle force [rate of force development (RFD)], muscle activation, and muscle size. Thirty-six subjects (60-86 yr) were randomized...... to a 12-wk rehabilitation program consisting of either 1) strength training (3 times/wk for 12 wk), 2) electrical muscle stimulation (1 h/day for 12 wk), or 3) standard rehabilitation (1 h/day for 12 wk). The nonoperated side did not receive any intervention and thereby served as a within-subject control...

  18. Submental sEMG and Hyoid Movement during Mendelsohn Maneuver, Effortful Swallow, and Expiratory Muscle Strength Training

    Science.gov (United States)

    Wheeler-Hegland, Karen M.; Rosenbek, John C.; Sapienza, Christine M.

    2008-01-01

    Purpose: This study investigated the concurrent biomechanical and electromyographic properties of 2 swallow-specific tasks (effortful swallow and Mendelsohn maneuver) and 1 swallow-nonspecific (expiratory muscle strength training [EMST]) swallow therapy task in order to examine the differential effects of each on hyoid motion and associated…

  19. Are chronic neck pain, scapular dyskinesis and altered scapulothoracic muscle activity interrelated?: A case-control study with surface and fine-wire EMG.

    Science.gov (United States)

    Castelein, Birgit; Cools, Ann; Parlevliet, Thierry; Cagnie, Barbara

    2016-12-01

    The function of the scapula is important in normal neck function and might be disturbed in patients with neck pain. The surrounding muscular system is important for the function of the scapula. To date, it is not clear if patients with idiopathic neck pain show altered activity of these scapulothoracic muscles. Therefore, the objective of this study was to investigate differences in deeper and superficial lying scapulothoracic muscle activity between patients with idiopathic neck pain and healthy controls during arm elevation, and to identify the influence of scapular dyskinesis on muscle activity. Scapular dyskinesis was rated with the yes/no method. The deeper lying (Levator Scapulae, Pectoralis Minor (Pm) and Rhomboid major) and superficial lying (Trapezius and Serratus Anterior) scapulothoracic muscles' activity was investigated with fine-wire and surface EMG, respectively, in 19 female subjects with idiopathic neck pain (age 28.3±10.1years, average duration of neck pain 45.6±36.3months) and 19 female healthy control subjects (age 29.3±11.7years) while performing scaption and towel wall slide. Possible interactions or differences between subject groups, scapular dyskinesis groups or phases of the task were studied with a linear mixed model. Higher Pm activity during the towel wallslide (p=0.024, mean difference 8.8±3.3% MVIC) was shown in patients with idiopathic neck pain in comparison with healthy controls. For the MT, a significant group∗dyskinesis interaction effect was found during scaption which revealed that patients with neck pain and scapular dyskinesis showed lower Middle Trapezius (MT) activity in comparison with healthy controls with scapular dyskinesis (p=0.029, mean difference 5.1±2.2% MVIC). In the presence of idiopathic neck pain, higher Pm activity during the towel wallslide was found. Patients with neck pain and scapular dyskinesis showed lower MT activity in comparison with healthy controls with scapular dyskinesis during scaption

  20. Trunk Muscle EMG During Intermediate Pilates Mat Exercises in Beginner Healthy and Chronic Low Back Pain Individuals.

    Science.gov (United States)

    Pereira, Ivye L R; Queiroz, Bergson; Loss, Jefferson; Amorim, César; Sacco, Isabel C N

    2017-06-01

    The purpose of this study was to compare the electromyographic pattern of core muscles during intermediate Pilates mat exercises between healthy people and those with low back pain. We evaluated healthy participants (n = 19; mean ± standard deviation [SD]: age 28 ± 8 years, body mass 65 ± 10 kg, height 160.0 ± 9.1 cm) and a low back pain group (n = 13; mean ± SD: age 30 ± 9 years, body mass 67 ± 12 kg, height 170.0 ± 6.6 cm). Electromyographic analysis assessed the multifidus, external oblique, internal oblique, and rectus abdominis muscles during classical Pilates exercises (single leg stretch, criss-cross, and dead bug). We calculated the root mean square normalized by maximum voluntary contraction, and the time of peak activation was provided by a linear envelope and normalized by the total movement cycle. The criss-cross exercise presented the highest values of root mean square for trunk flexors (rectus abdominis and oblique) compared with the other exercises, followed by the single leg stretch and the dead bug, which had similar muscle activation. The single leg stretch presented more activation of the rectus abdominis and oblique, whereas the criss-cross and dead bug created more activation of the oblique compared with the multifidus and rectus. The Pilates exercises presented different muscle recruitment patterns, and allowed the activation of the lumbopelvic stabilizing muscles even in the first session for healthy individuals and those with chronic low back pain. Copyright © 2017. Published by Elsevier Inc.

  1. Experimentally Induced Stress Validated by EMG Activity

    Science.gov (United States)

    Luijcks, Rosan; Hermens, Hermie J.; Bodar, Lonneke; Vossen, Catherine J.; Os, Jim van.; Lousberg, Richel

    2014-01-01

    Experience of stress may lead to increased electromyography (EMG) activity in specific muscles compared to a non-stressful situation. The main aim of this study was to develop and validate a stress-EMG paradigm in which a single uncontrollable and unpredictable nociceptive stimulus was presented. EMG activity of the trapezius muscles was the response of interest. In addition to linear time effects, non-linear EMG time courses were also examined. Taking into account the hierarchical structure of the dataset, a multilevel random regression model was applied. The stress paradigm, executed in N = 70 subjects, consisted of a 3-minute baseline measurement, a 3-minute pre-stimulus stress period and a 2-minute post-stimulus phase. Subjects were unaware of the precise moment of stimulus delivery and its intensity level. EMG activity during the entire experiment was conform a priori expectations: the pre-stimulus phase showed a significantly higher mean EMG activity level compared to the other two phases, and an immediate EMG response to the stimulus was demonstrated. In addition, the analyses revealed significant non-linear EMG time courses in all three phases. Linear and quadratic EMG time courses were significantly modified by subjective anticipatory stress level, measured just before the start of the stress task. Linking subjective anticipatory stress to EMG stress reactivity revealed that subjects with a high anticipatory stress level responded with more EMG activity during the pre-stimulus stress phase, whereas subjects with a low stress level showed an inverse effect. Results suggest that the stress paradigm presented here is a valid test to quantify individual differences in stress susceptibility. Further studies with this paradigm are required to demonstrate its potential use in mechanistic clinical studies. PMID:24736740

  2. Experimentally induced stress validated by EMG activity.

    Science.gov (United States)

    Luijcks, Rosan; Hermens, Hermie J; Bodar, Lonneke; Vossen, Catherine J; Van Os, Jim; Lousberg, Richel

    2014-01-01

    Experience of stress may lead to increased electromyography (EMG) activity in specific muscles compared to a non-stressful situation. The main aim of this study was to develop and validate a stress-EMG paradigm in which a single uncontrollable and unpredictable nociceptive stimulus was presented. EMG activity of the trapezius muscles was the response of interest. In addition to linear time effects, non-linear EMG time courses were also examined. Taking into account the hierarchical structure of the dataset, a multilevel random regression model was applied. The stress paradigm, executed in N = 70 subjects, consisted of a 3-minute baseline measurement, a 3-minute pre-stimulus stress period and a 2-minute post-stimulus phase. Subjects were unaware of the precise moment of stimulus delivery and its intensity level. EMG activity during the entire experiment was conform a priori expectations: the pre-stimulus phase showed a significantly higher mean EMG activity level compared to the other two phases, and an immediate EMG response to the stimulus was demonstrated. In addition, the analyses revealed significant non-linear EMG time courses in all three phases. Linear and quadratic EMG time courses were significantly modified by subjective anticipatory stress level, measured just before the start of the stress task. Linking subjective anticipatory stress to EMG stress reactivity revealed that subjects with a high anticipatory stress level responded with more EMG activity during the pre-stimulus stress phase, whereas subjects with a low stress level showed an inverse effect. Results suggest that the stress paradigm presented here is a valid test to quantify individual differences in stress susceptibility. Further studies with this paradigm are required to demonstrate its potential use in mechanistic clinical studies.

  3. Experimentally induced stress validated by EMG activity.

    Directory of Open Access Journals (Sweden)

    Rosan Luijcks

    Full Text Available Experience of stress may lead to increased electromyography (EMG activity in specific muscles compared to a non-stressful situation. The main aim of this study was to develop and validate a stress-EMG paradigm in which a single uncontrollable and unpredictable nociceptive stimulus was presented. EMG activity of the trapezius muscles was the response of interest. In addition to linear time effects, non-linear EMG time courses were also examined. Taking into account the hierarchical structure of the dataset, a multilevel random regression model was applied. The stress paradigm, executed in N = 70 subjects, consisted of a 3-minute baseline measurement, a 3-minute pre-stimulus stress period and a 2-minute post-stimulus phase. Subjects were unaware of the precise moment of stimulus delivery and its intensity level. EMG activity during the entire experiment was conform a priori expectations: the pre-stimulus phase showed a significantly higher mean EMG activity level compared to the other two phases, and an immediate EMG response to the stimulus was demonstrated. In addition, the analyses revealed significant non-linear EMG time courses in all three phases. Linear and quadratic EMG time courses were significantly modified by subjective anticipatory stress level, measured just before the start of the stress task. Linking subjective anticipatory stress to EMG stress reactivity revealed that subjects with a high anticipatory stress level responded with more EMG activity during the pre-stimulus stress phase, whereas subjects with a low stress level showed an inverse effect. Results suggest that the stress paradigm presented here is a valid test to quantify individual differences in stress susceptibility. Further studies with this paradigm are required to demonstrate its potential use in mechanistic clinical studies.

  4. Clinical applications of high-density surface EMG: a systematic review.

    NARCIS (Netherlands)

    Drost, G.; Stegeman, D.F.; Engelen, B.G.M. van; Zwarts, M.J.

    2006-01-01

    High density-surface EMG (HD-sEMG) is a non-invasive technique to measure electrical muscle activity with multiple (more than two) closely spaced electrodes overlying a restricted area of the skin. Besides temporal activity HD-sEMG also allows spatial EMG activity to be recorded, thus expanding the

  5. Clinical applications of high-density surface EMG: A systematic review

    NARCIS (Netherlands)

    Drost, G; Stegeman, D.F.; van Engelen, B.G.M.; Smeitink, J.A.M.; Rodenburg, J.A.; Hol, F.A.

    2006-01-01

    High density-surface EMG (HD-sEMG) is a non-invasive technique to measure electrical muscle activity with multiple (more than two) closely spaced electrodes overlying a restricted area of the skin. Besides temporal activity HD-sEMG also allows spatial EMG activity to be recorded, thus expanding the

  6. A literature review of the methodology of EMG recordings of the diaphragm

    NARCIS (Netherlands)

    Hutten, G. J.; van Thuijl, H. F.; van Bellegem, A. C. M.; van Eykern, L. A.; van Aalderen, W. M. C.

    2010-01-01

    Introduction: EMG measurements of the diaphragm (rEMG) provide insight in to ventilatory muscle activity. Applicability of these measurements has improved, but literature of the different rEMG measurement techniques is inconsistent. This makes it difficult to compare studies of rEMG technique. This

  7. Interpreting Changes in Surface EMG Amplitude During High-Level Fatiguing Contractions of the Brachioradialis

    National Research Council Canada - National Science Library

    Lowery, M

    2001-01-01

    ... to estimate muscle fatigue. In this paper, theoretical relationships between surface EMG amplitude measures and mean motor unit firing rates and muscle fiber conduction velocity (MFCV) are established...

  8. Evaluation of muscle fatigue of wheelchair basketball players with spinal cord injury using recurrence quantification analysis of surface EMG.

    Science.gov (United States)

    Uzun, S; Pourmoghaddam, A; Hieronymus, M; Thrasher, T A

    2012-11-01

    Wheelchair basketball is the most popular exercise activity among individuals with spinal cord injury (SCI). The purpose of this study was to investigate muscular endurance and fatigue in wheelchair basketball athletes with SCI using surface electromyography (SEMG) and maximal torque values. SEMG characteristics of 10 wheelchair basketball players (WBP) were compared to 13 able-bodied basketball players and 12 sedentary able-bodied subjects. Participants performed sustained isometric elbow flexion at 50% maximal voluntary contraction until exhaustion. Elbow flexion torque and SEMG signals were recorded from three elbow flexor muscles: biceps brachii longus, biceps brachii brevis and brachioradialis. SEMG signals were clustered into 0.5-s epochs with 50% overlap. Root mean square (RMS) and median frequency (MDF) of SEMG signals were calculated for each muscle and epoch as traditional fatigue monitoring. Recurrence quantification analysis was used to extract the percentage of determinism (%DET) of SEMG signals. The slope of the %DET for basketball players and WBP showed slower increase with time than the sedentary able-bodied control group for three different elbow flexor muscles, while no difference was observed for the slope of the %DET between basketball and WBP. This result indicated that the athletes are less fatigable during the task effort than the nonathletes. Normalized MDF slope decay exhibited similar results between the groups as %DET, while the slope of the normalized RMS failed to show any significant differences among the groups (p > 0.05). MDF and %DET could be useful for the evaluation of muscle fatigue in wheelchair basketball training. No conclusions about special training for WBP could be determined.

  9. EMG MEDIAN POWER FREQUENCY IN AN EXHAUSTING EXERCISE

    NARCIS (Netherlands)

    AMENT, W; BONGA, GJJ; HOF, AL; VERKERKE, GJ

    1993-01-01

    EMG median power frequency of the calf muscles was investigated during an exhausting treadmill exercise. This exercise was an uphill run, the average endurance time was 1.5 min. Median power frequency of the calf muscles declined by more than 10% during this exercise. In addition EMG median power

  10. Surface EMG parameters in schizophrenia patients.

    Science.gov (United States)

    Miroshnichenko, German; Kuzmina, Anna; Meigal, Alexander; Burkin, Mark; Rissanen, Saara M; Karjalainen, Pasi A

    2014-01-01

    The aim of the study was to compare a variety of surface EMG (sEMG) parameters in several groups of schizophrenia (SZ, n=69) patients and healthy controls (n=44). We computed spectral, mutual information (MI) based and recurrence quantification analysis (RQA) parameters of sEMG. The major finding is that sEMG of the controls had higher values of the MI-based parameter, mean and median spectrum frequencies, and lower values of most of RQA parameters. It means higher content of recurrent fragments in sEMG of SZ patients. We suggest that the differences might be caused by either denervation/renervation process of single muscle fibers in SZ patients and/or by increased motor unit synchronization induced by antipsychotic therapy.

  11. Simultaneous 31P-NMR spectroscopy and EMG in exercising and recovering human skeletal muscle: a correlation study

    DEFF Research Database (Denmark)

    Vestergaard-Poulsen, P; Thomsen, C; Sinkjaer, T

    1995-01-01

    A large number of studies have shown amplitude and spectral changes of the electromyogram during exercise, leading to several theories of how these changes might be related to the underlying metabolic changes. The amplitude and spectral changes are generally interpreted as changes in motor unit...... recruitment and a reduction of the muscle fiber conduction velocity due to proton or lactate accumulation. This study focuses on the causality of spectral changes of the surface electromyogram and proton or lactate accumulation and how the changes in motor unit recruitment are related to the metabolic status...... and pH was seen in the healthy volunteers during recovery and during exercise in the patient with McArdle's disease. The results indicate that proton or lactate accumulation is not primarily responsible for the spectral changes of the surface electromyogram as previously suggested. The motor unit...

  12. EMG evaluation of hip adduction exercises for soccer players

    DEFF Research Database (Denmark)

    Serner, Andreas; Jakobsen, Markus Due; Andersen, Lars Louis

    2014-01-01

    traditional and two new hip adduction exercises. Additionally, to analyse muscle activation of gluteals and abdominals. MATERIALS AND METHODS: 40 healthy male elite soccer players, training >5 h a week, participated in the study. Muscle activity using surface electromyography (sEMG) was measured bilaterally...... for the adductor longus during eight hip adduction strengthening exercises and peak EMG was normalised (nEMG) using an isometric maximal voluntary contraction (MVC) as reference. Furthermore, muscle activation of the gluteus medius, rectus abdominis and the external abdominal obliques was analysed during...... the exercises. RESULTS: There were large differences in peak nEMG of the adductor longus between the exercises, with values ranging from 14% to 108% nEMG (pEMG results for the gluteals...

  13. Identification of the occurrence and pattern of masseter muscle activities during sleep using EMG and accelerometer systems

    Directory of Open Access Journals (Sweden)

    Sato Sadao

    2009-02-01

    Full Text Available Abstract Background Sleep bruxism has been described as a combination of different orofacial motor activities that include grinding, clenching and tapping, although accurate distribution of the activities still remains to be clarified. Methods We developed a new system for analyzing sleep bruxism to examine the muscle activities and mandibular movement patterns during sleep bruxism. The system consisted of a 2-axis accelerometer, electroencephalography and electromyography. Nineteen healthy volunteers were recruited and screened to evaluate sleep bruxism in the sleep laboratory. Results The new system could easily distinguish the different patterns of bruxism movement of the mandible and the body movement. Results showed that grinding (59.5% was most common, followed by clenching (35.6% based on relative activity to maximum voluntary contraction (%MVC, whereas tapping was only (4.9%. Conclusion It was concluded that the tapping, clenching, and grinding movement of the mandible could be effectively differentiated by the new system and sleep bruxism was predominantly perceived as clenching and grinding, which varied between individuals.

  14. Identification of the occurrence and pattern of masseter muscle activities during sleep using EMG and accelerometer systems

    Science.gov (United States)

    Yoshimi, Hidehiro; Sasaguri, Kenichi; Tamaki, Katsushi; Sato, Sadao

    2009-01-01

    Background Sleep bruxism has been described as a combination of different orofacial motor activities that include grinding, clenching and tapping, although accurate distribution of the activities still remains to be clarified. Methods We developed a new system for analyzing sleep bruxism to examine the muscle activities and mandibular movement patterns during sleep bruxism. The system consisted of a 2-axis accelerometer, electroencephalography and electromyography. Nineteen healthy volunteers were recruited and screened to evaluate sleep bruxism in the sleep laboratory. Results The new system could easily distinguish the different patterns of bruxism movement of the mandible and the body movement. Results showed that grinding (59.5%) was most common, followed by clenching (35.6%) based on relative activity to maximum voluntary contraction (%MVC), whereas tapping was only (4.9%). Conclusion It was concluded that the tapping, clenching, and grinding movement of the mandible could be effectively differentiated by the new system and sleep bruxism was predominantly perceived as clenching and grinding, which varied between individuals. PMID:19208264

  15. A new EMG frequency-based fatigue threshold test.

    Science.gov (United States)

    Hendrix, C Russell; Housh, Terry J; Johnson, Glen O; Mielke, Michelle; Camic, Clayton L; Zuniga, Jorge M; Schmidt, Richard J

    2009-06-30

    Theoretically, the critical torque (CT) and electromyographic mean power frequency fatigue threshold (EMG MPF(FT)) describe the maximal non-fatiguing isometric torque level. The purposes of this study were two-fold: (1) to determine if the mathematical model for estimating the EMG fatigue threshold (EMG(FT)) from the amplitude of the EMG signal was applicable to the frequency domain of the EMG signal to estimate a new fatigue threshold called the EMG MPF(FT); and (2) to compare the torque level derived from the CT test to that of the EMG MPF(FT) test for the vastus lateralis (VL) muscle during isometric muscle actions of the leg extensors. Nine adults (4 men and 5 women; mean+/-SD age=21.6+/-1.2 yr) performed three or four continuous, fatiguing, isometric muscle actions of the leg extensors at 30, 45, 60, and 75% of maximum voluntary isometric contraction (MVIC) to determine the time to exhaustion (T(lim)) values. The slope coefficient of the linear relationship between total isometric "work" (W(lim) in Nms=TorquexT(lim)) and T(lim) was defined as the CT. Surface EMG signals were recorded from the vastus lateralis (VL) muscle during each fatiguing isometric muscle action. The EMG MPF(FT) was defined as the y-intercept of the isometric torque versus slope coefficient (EMG MPF versus time) plot. There were no significant differences between CT (19.7+/-5.8%MVIC) and EMG MPF(FT) (21.4+/-8.7%MVIC). These findings provided indirect validation of the EMG MPF(FT) test.

  16. Correlated EMG Oscillations between Antagonists during Cocontraction in Men.

    Science.gov (United States)

    Yoshitake, Yasuhide; Kanehisa, Hiroaki; Shinohara, Minoru

    2017-03-01

    The purpose of this study was to determine the modulation of common low-frequency oscillations in pools of motor units across antagonistic muscles because of the difference in the activation level of pools of spinal motor neurons and the presence of neuromuscular fatigue during intended cocontraction. Ten healthy young men (21.8 ± 1.5 yr) performed intended steady cocontractions of elbow flexors and extensors at maximal and a submaximal (10% of maximal EMG) effort. The submaximal cocontraction was repeated after sustained maximal contraction of elbow flexors. Surface EMG was recorded from the biceps brachii and triceps brachii muscles. Correlated EMG oscillations between the antagonistic muscles were quantified by the cross-correlation function (CCF) using rectified EMG for the EMG for the 3- to 15-Hz bands. The positive CCF peak in rectified EMG EMG, a negative CCF peak (i.e., out-of-phase oscillations) during submaximal cocontraction was smaller compared with maximal cocontraction but increased after the sustained contraction. Across subjects, the degree of reduction in maximal EMG amplitude after the sustained contraction was correlated with the amount of change in the CCF peak in EMG oscillations between antagonistic muscles occur during intended cocontraction, and 2) the magnitude of these correlated oscillations increases with the activation level of pools of spinal motor neurons and neuromuscular fatigue.

  17. Gesture Based Control and EMG Decomposition

    Science.gov (United States)

    Wheeler, Kevin R.; Chang, Mindy H.; Knuth, Kevin H.

    2005-01-01

    This paper presents two probabilistic developments for use with Electromyograms (EMG). First described is a new-electric interface for virtual device control based on gesture recognition. The second development is a Bayesian method for decomposing EMG into individual motor unit action potentials. This more complex technique will then allow for higher resolution in separating muscle groups for gesture recognition. All examples presented rely upon sampling EMG data from a subject's forearm. The gesture based recognition uses pattern recognition software that has been trained to identify gestures from among a given set of gestures. The pattern recognition software consists of hidden Markov models which are used to recognize the gestures as they are being performed in real-time from moving averages of EMG. Two experiments were conducted to examine the feasibility of this interface technology. The first replicated a virtual joystick interface, and the second replicated a keyboard. Moving averages of EMG do not provide easy distinction between fine muscle groups. To better distinguish between different fine motor skill muscle groups we present a Bayesian algorithm to separate surface EMG into representative motor unit action potentials. The algorithm is based upon differential Variable Component Analysis (dVCA) [l], [2] which was originally developed for Electroencephalograms. The algorithm uses a simple forward model representing a mixture of motor unit action potentials as seen across multiple channels. The parameters of this model are iteratively optimized for each component. Results are presented on both synthetic and experimental EMG data. The synthetic case has additive white noise and is compared with known components. The experimental EMG data was obtained using a custom linear electrode array designed for this study.

  18. Seizure detection algorithms based on EMG signals

    DEFF Research Database (Denmark)

    Conradsen, Isa

    Background: the currently used non-invasive seizure detection methods are not reliable. Muscle fibers are directly connected to the nerves, whereby electric signals are generated during activity. Therefore, an alarm system on electromyography (EMG) signals is a theoretical possibility. Objective......: to show whether medical signal processing of EMG data is feasible for detection of epileptic seizures. Methods: EMG signals during generalised seizures were recorded from 3 patients (with 20 seizures in total). Two possible medical signal processing algorithms were tested. The first algorithm was based...... the frequency-based algorithm was efficient for detecting the seizures in the third patient. Conclusion: Our results suggest that EMG signals could be used to develop an automatic seizuredetection system. However, different patients might require different types of algorithms /approaches....

  19. Speed dependence of averaged EMG profiles in walking

    NARCIS (Netherlands)

    Hof, AL; Elzinga, H; Grimmius, W; Halbertsma, JPK

    Electromyogram (EMG) profiles strongly depend on walking speed and, in pathological gait, patients do not usually walk at normal speeds. EMG data was collected from 14 muscles in two groups of healthy young subjects who walked at five different speeds ranging from 0.75 to 1.75 ms(-1). We found that

  20. Predicting 3D lip shapes using facial surface EMG

    OpenAIRE

    Eskes, Merijn; van Alphen, Maarten J. A.; Balm, Alfons J. M.; Smeele, Ludi E.; Brandsma, Dieta; van der Heijden, Ferdinand

    2017-01-01

    Aim The aim of this study is to prove that facial surface electromyography (sEMG) conveys sufficient information to predict 3D lip shapes. High sEMG predictive accuracy implies we could train a neural control model for activation of biomechanical models by simultaneously recording sEMG signals and their associated motions. Materials and methods With a stereo camera set-up, we recorded 3D lip shapes and simultaneously performed sEMG measurements of the facial muscles, applying principal compon...

  1. The Response of Hyperkinesis to EMG Biofeedback.

    Science.gov (United States)

    Haight, Maryellen J.; And Others

    A study was conducted involving eight hyperkinetic males (11-15 years old) to determine if Ss receiving electromyography (EMG) biofeedback training would show a reduction in frontalis muscle tension, hyperactivity, and lability, and increases in self-esteem and visual and auditory attention span. Individual 45- and 30-minute relaxation exercises…

  2. Wideband EMG telemetry system

    Science.gov (United States)

    Rosatino, S. A.; Westbrook, R. M.

    1979-01-01

    Miniature, individual crystal-controlled RF transmitters located in EMG pressure sensors simplifies multichannel EMG telemetry for electronic gait monitoring. Transmitters which are assigned operating frequencies within 174 - 216 MHz band have linear frequency response from 20 - 2000 Hz and operate over range of 15 m.

  3. The effectiveness of EMG biofeedback training in low back pain.

    Science.gov (United States)

    Nouwen, A; Solinger, J W

    1979-06-01

    Eighteen patients with chronic low back pain (lbp) of muscle tension origin were given an EMG biofeedback training. Compared to seven controls they showed a significant decrease during training in muscle tension and subsequently in pain. However, at follow-up EMG levels dropped to the initial (high) level. Pain scores of patients with high pain decrements during training showed further improvement during follow-up, which was not the case with patients showing less substantial improvement. The importance of cognitions was discussed.

  4. The use of surface EMG in knee extensor moment prediction.

    Science.gov (United States)

    Cheng, C K; Hsiung, H S; Lai, J S

    1994-10-01

    A systematic method of EMG quantification is developed to estimate the isometric muscle moment directly from quantified surface EMG. This method includes the EMG Signals acquired from an acupuncture point Fu-Tu located on the quadriceps muscle group, an EMG smoothing scheme, an electromechanical time lag estimation, and a mathematical model with the polynomial regression function to quantify the EMG. Three subjects were asked to be tested on the CYBEX II dynamometer with a knee joint angle of 90 degree flexion and hip joint angle of also 90 degrees. They were asked to perform "two" trials of maximal voluntary contraction and "three" trials of free voluntary contraction of the isometric exercise. The first two trials were used to build up the quantification model, and the latter three trials served as data for the validation of the method. A Medelec MS92 EMG system with surface EMG electrodes was used to acquire the EMG Signals. In the determination of the regression order of the polynomial equations, the threshold value 0.0001 of the difference of the coefficient of determination values was used. The results of the polynomial regression orders are all 6 for three subjects, which reflects a tendency of nonlinear behavior of the EMG/moment relationship. A validation scheme was proposed to calculate the root mean square difference (RMSD) of the measured knee extensor moments from the CYBEX II dynamometer and estimated moments from the EMG quantification. The mean values of the RMSD of the three subjects were 0.0597, 0.0679 and 0.1080. These results demonstrate that the present approach can estimate the isometric muscle moment exerted by the quadriceps muscle group.

  5. siGnum: graphical user interface for EMG signal analysis.

    Science.gov (United States)

    Kaur, Manvinder; Mathur, Shilpi; Bhatia, Dinesh; Verma, Suresh

    2015-01-01

    Electromyography (EMG) signals that represent the electrical activity of muscles can be used for various clinical and biomedical applications. These are complicated and highly varying signals that are dependent on anatomical location and physiological properties of the muscles. EMG signals acquired from the muscles require advanced methods for detection, decomposition and processing. This paper proposes a novel Graphical User Interface (GUI) siGnum developed in MATLAB that will apply efficient and effective techniques on processing of the raw EMG signals and decompose it in a simpler manner. It could be used independent of MATLAB software by employing a deploy tool. This would enable researcher's to gain good understanding of EMG signal and its analysis procedures that can be utilized for more powerful, flexible and efficient applications in near future.

  6. Intramuscular pressure and EMG relate during static contractions but dissociate with movement and fatigue

    DEFF Research Database (Denmark)

    Sjøgaard, Gisela; Jensen, Bente R; Hargens, Alan R

    2004-01-01

    Intramuscular pressure (IMP) and electromyography (EMG) mirror muscle force in the nonfatigued muscle during static contractions. The present study explores whether the constant IMP-EMG relationship with increased force may be extended to dynamic contractions and to fatigued muscle. IMP and EMG...... were recorded from shoulder muscles in three sessions: 1). brief static arm abductions at angles from 0 to 90 degrees, with and without 1 kg in the hands; 2). dynamic arm abductions at angular velocities from 9 to 90 degrees /s, with and without 1 kg in the hands; and 3). prolonged static arm abduction...... at 30 degrees for 30 min followed by recovery. IMP and EMG increased in parallel with increasing shoulder torque during brief static tasks. During dynamic contractions, peak IMP and EMG increased to values higher than those during static contractions, and EMG, but not IMP, increased significantly...

  7. Effects of innovative virtual reality game and EMG biofeedback on neuromotor control in cerebral palsy.

    Science.gov (United States)

    Yoo, Ji Won; Lee, Dong Ryul; Sim, Yon Ju; You, Joshua H; Kim, Cheol J

    2014-01-01

    Sensorimotor control dysfunction or dyskinesia is a hallmark of neuromuscular impairment in children with cerebral palsy (CP), and is often implicated in reaching and grasping deficiencies due to a neuromuscular imbalance between the triceps and biceps. To mitigate such muscle imbalances, an innovative electromyography (EMG)-virtual reality (VR) biofeedback system were designed to provide accurate information about muscle activation and motivation. However, the clinical efficacy of this approach has not yet been determined in children with CP. The purpose of this study was to investigate the effectiveness of a combined EMG biofeedback and VR (EMG-VR biofeedback) intervention system to improve muscle imbalance between triceps and biceps during reaching movements in children with spastic CP. Raw EMG signals were recorded at a sampling rate of 1,000 Hz, band-pass filtered between 20-450 Hz, and notch-filtered at 60 Hz during elbow flexion and extension movements. EMG data were then processed using MyoResearch Master Edition 1.08 XP software. All participants underwent both interventions consisting of the EMG-VR biofeedback combination and EMG biofeedback alone. EMG analysis resulted in improved muscle activation in the underactive triceps while decreasing overactive or hypertonic biceps in the EMG-VR biofeedback compared with EMG biofeedback. The muscle imbalance ratio between the triceps and biceps was consistently improved. The present study is the first clinical trial to provide evidence for the additive benefits of VR intervention for enhancing the upper limb function of children with spastic CP.

  8. A Study on EMG-based Biometrics

    Directory of Open Access Journals (Sweden)

    Jin Su Kim

    2017-05-01

    Full Text Available Biometrics is a technology that recognizes user's information by using unique physical features of his or her body such as face, fingerprint, and iris. It also uses behavioral features such as signature, electrocardiogram (ECG, electromyogram (EMG, and electroencephalogram (EEG. Among them, the EMG signal is a sign generated when the muscles move, which can be used in various fields such as motion recognition, personal identification, and disease diagnosis. In this paper, we analyze EMG-based biometrics and implement a motion recognition and personal identification system. The system extracted features using non-uniform filter bank and Waveform Length (WL, and reduces the dimension using Principal Component Analysis (PCA and Linear Discriminant Analysis (LDA. Afterward, it classified the features using Euclidean Distance (ED, Support Vector Machine (SVM and K Nearest Neighbors (KNN. As a result of the motion recognition experiment, 95% of acquired EMG data and 84.66% of UCI data were obtained and as a result of the personal recognition experiment, 85% of acquired EMG data and 88.66% of UCI data were obtained.

  9. Detection radius of EMG for fasciculations: Empiric study combining ultrasonography and electromyography.

    Science.gov (United States)

    Regensburger, Martin; Tenner, Felix; Möbius, Cornelia; Schramm, Axel

    2017-11-21

    The aims of this study were to investigate the detection radius and sensitivity of EMG for fasciculations. Muscle ultrasonography was performed simultaneously to EMG recordings in patients with fasciculations in the context of amyotrophic lateral sclerosis. Ultrasonography and EMG parameters were analyzed for selected fasciculations. A total of 381 fasciculations were detected by ultrasonography in 18 muscles of 10 patients. Out of these, 125 (33%) were EMG-negative. In contrast, none of the fasciculations detected by EMG were ultrasonography-negative. EMG detection probability decreased significantly with increasing distance from the center of the fasciculation. EMG detection rate was 98% when the EMG needle was located within the fasciculation and 50% at 7.75 mm distance from the fasciculation center. In addition, EMG detection depended significantly on cross-sectional area of the fasciculation and presence of neurogenic changes. For detecting the same fasciculations, EMG is less sensitive than ultrasonography. EMG detection probability decreases sharply at a distance comparable to motor unit size. These results extend previous knowledge about superior sensitivity of ultrasonography for fasciculations. Moreover, our novel bimodal detection method provides first in vivo data about the EMG detection radius for fasciculations in a clinical setting. Copyright © 2017. Published by Elsevier B.V.

  10. A method for discrimination of noise and EMG signal regions recorded during rhythmic behaviors.

    Science.gov (United States)

    Ying, Rex; Wall, Christine E

    2016-12-08

    Analyses of muscular activity during rhythmic behaviors provide critical data for biomechanical studies. Electrical potentials measured from muscles using electromyography (EMG) require discrimination of noise regions as the first step in analysis. An experienced analyst can accurately identify the onset and offset of EMG but this process takes hours to analyze a short (10-15s) record of rhythmic EMG bursts. Existing computational techniques reduce this time but have limitations. These include a universal threshold for delimiting noise regions (i.e., a single signal value for identifying the EMG signal onset and offset), pre-processing using wide time intervals that dampen sensitivity for EMG signal characteristics, poor performance when a low frequency component (e.g., DC offset) is present, and high computational complexity leading to lack of time efficiency. We present a new statistical method and MATLAB script (EMG-Extractor) that includes an adaptive algorithm to discriminate noise regions from EMG that avoids these limitations and allows for multi-channel datasets to be processed. We evaluate the EMG-Extractor with EMG data on mammalian jaw-adductor muscles during mastication, a rhythmic behavior typified by low amplitude onsets/offsets and complex signal pattern. The EMG-Extractor consistently and accurately distinguishes noise from EMG in a manner similar to that of an experienced analyst. It outputs the raw EMG signal region in a form ready for further analysis. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Analysis of EMG Signals in Aggressive and Normal Activities by Using Higher-Order Spectra

    Directory of Open Access Journals (Sweden)

    Necmettin Sezgin

    2012-01-01

    Full Text Available The analysis and classification of electromyography (EMG signals are very important in order to detect some symptoms of diseases, prosthetic arm/leg control, and so on. In this study, an EMG signal was analyzed using bispectrum, which belongs to a family of higher-order spectra. An EMG signal is the electrical potential difference of muscle cells. The EMG signals used in the present study are aggressive or normal actions. The EMG dataset was obtained from the machine learning repository. First, the aggressive and normal EMG activities were analyzed using bispectrum and the quadratic phase coupling of each EMG episode was determined. Next, the features of the analyzed EMG signals were fed into learning machines to separate the aggressive and normal actions. The best classification result was 99.75%, which is sufficient to significantly classify the aggressive and normal actions.

  12. Lower extremity muscles activity in standing and sitting position with use of sEMG in patients suffering from Charcot-Marie-Tooth syndrome.

    Science.gov (United States)

    Kuciel, Natalia Maria; Konieczny, Grzegorz Krzysztof; Oleksy, Łukasz; Wrzosek, Zdzisława

    2016-01-01

    There is very limited, evidenced data about movement possibilities in patients with high level of lower limb muscles atrophy and fatigue in patients suffering from Charcot-Marie-Tooth syndrome. Patient (age 46) suffering from Charcot-Marie-Tooth disease for 30 years with multiple movement restrictions and muscles atrophy above knees took part into the study. Tests were performed for 8 muscles of the lower limb and pelvis. Muscles electrical activity was tested in sitting and standing position (for knees extended and hyperextended). In the right leg rectus femoris, vastus lateralis obliquus, gluteus medius and semitendinosus muscles activated at first and were working the longest time. The highest activity was observed in standing position with knees extended. In the left leg rectus femoris and biceps femoris muscles activated at first and biceps femoris was working the longest time. Activity level in left lower limb is much lower than in the right one. Muscles weakness is asymmetric. Left leg is much weaker and engages antagonists and synergists muscles to compensate weaker rectus femoris, vastus medialis obliquus and vastus lateralis obliquus. Copyright © 2016. Published by Elsevier Urban & Partner Sp. z o.o.

  13. Behaviour of a surface EMG based measure for motor control: Motor unit action potential rate in relation to force and muscle fatigue

    NARCIS (Netherlands)

    Kallenberg, L.A.C.; Hermens, Hermanus J.

    2008-01-01

    Surface electromyography parameters such as root-mean-square value (RMS) and median power frequency (FMED) are commonly used to assess the input of the central nervous system (CNS) to a muscle. However, RMS and FMED are influenced not only by CNS input, but also by peripheral muscle properties. The

  14. EMG patterns during assisted walking in the exoskeleton.

    Science.gov (United States)

    Sylos-Labini, Francesca; La Scaleia, Valentina; d'Avella, Andrea; Pisotta, Iolanda; Tamburella, Federica; Scivoletto, Giorgio; Molinari, Marco; Wang, Shiqian; Wang, Letian; van Asseldonk, Edwin; van der Kooij, Herman; Hoellinger, Thomas; Cheron, Guy; Thorsteinsson, Freygardur; Ilzkovitz, Michel; Gancet, Jeremi; Hauffe, Ralf; Zanov, Frank; Lacquaniti, Francesco; Ivanenko, Yuri P

    2014-01-01

    Neuroprosthetic technology and robotic exoskeletons are being developed to facilitate stepping, reduce muscle efforts, and promote motor recovery. Nevertheless, the guidance forces of an exoskeleton may influence the sensory inputs, sensorimotor interactions and resulting muscle activity patterns during stepping. The aim of this study was to report the muscle activation patterns in a sample of intact and injured subjects while walking with a robotic exoskeleton and, in particular, to quantify the level of muscle activity during assisted gait. We recorded electromyographic (EMG) activity of different leg and arm muscles during overground walking in an exoskeleton in six healthy individuals and four spinal cord injury (SCI) participants. In SCI patients, EMG activity of the upper limb muscles was augmented while activation of leg muscles was typically small. Contrary to our expectations, however, in neurologically intact subjects, EMG activity of leg muscles was similar or even larger during exoskeleton-assisted walking compared to normal overground walking. In addition, significant variations in the EMG waveforms were found across different walking conditions. The most variable pattern was observed in the hamstring muscles. Overall, the results are consistent with a non-linear reorganization of the locomotor output when using the robotic stepping devices. The findings may contribute to our understanding of human-machine interactions and adaptation of locomotor activity patterns.

  15. Using State-Space Model with Regime Switching to Represent the Dynamics of Facial Electromyography (EMG) Data

    Science.gov (United States)

    Yang, Manshu; Chow, Sy-Miin

    2010-01-01

    Facial electromyography (EMG) is a useful physiological measure for detecting subtle affective changes in real time. A time series of EMG data contains bursts of electrical activity that increase in magnitude when the pertinent facial muscles are activated. Whereas previous methods for detecting EMG activation are often based on deterministic or…

  16. Adaptive neuron-to-EMG decoder training for FES neuroprostheses

    Science.gov (United States)

    Ethier, Christian; Acuna, Daniel; Solla, Sara A.; Miller, Lee E.

    2016-08-01

    Objective. We have previously demonstrated a brain-machine interface neuroprosthetic system that provided continuous control of functional electrical stimulation (FES) and restoration of grasp in a primate model of spinal cord injury (SCI). Predicting intended EMG directly from cortical recordings provides a flexible high-dimensional control signal for FES. However, no peripheral signal such as force or EMG is available for training EMG decoders in paralyzed individuals. Approach. Here we present a method for training an EMG decoder in the absence of muscle activity recordings; the decoder relies on mapping behaviorally relevant cortical activity to the inferred EMG activity underlying an intended action. Monkeys were trained at a 2D isometric wrist force task to control a computer cursor by applying force in the flexion, extension, ulnar, and radial directions and execute a center-out task. We used a generic muscle force-to-endpoint force model based on muscle pulling directions to relate each target force to an optimal EMG pattern that attained the target force while minimizing overall muscle activity. We trained EMG decoders during the target hold periods using a gradient descent algorithm that compared EMG predictions to optimal EMG patterns. Main results. We tested this method both offline and online. We quantified both the accuracy of offline force predictions and the ability of a monkey to use these real-time force predictions for closed-loop cursor control. We compared both offline and online results to those obtained with several other direct force decoders, including an optimal decoder computed from concurrently measured neural and force signals. Significance. This novel approach to training an adaptive EMG decoder could make a brain-control FES neuroprosthesis an effective tool to restore the hand function of paralyzed individuals. Clinical implementation would make use of individualized EMG-to-force models. Broad generalization could be achieved by

  17. Design of microcontroller-based EMG and the analysis of EMG signals.

    Science.gov (United States)

    Güler, Nihal Fatma; Hardalaç, Firat

    2002-04-01

    In this work, a microcontroller-based EMG designed and tested on 40 patients. When the patients are in rest, the fast Fourier transform (FFT) analysis was applied to EMG signals recorded from right leg peroneal region. The histograms are constructed from the results of the FFT analysis. The analysis results shows that the amplitude of fibrillation potential of the muscle fiber of 30 patients measured from peroneal region is low and the duration is short. This is the reason why the motor nerves degenerated and 10 patients were found to be healthy.

  18. An EMG-CT method using multiple surface electrodes in the forearm.

    Science.gov (United States)

    Nakajima, Yasuhiro; Keeratihattayakorn, Saran; Yoshinari, Satoshi; Tadano, Shigeru

    2014-12-01

    Electromyography computed tomography (EMG-CT) method is proposed for visualizing the individual muscle activities in the human forearm. An EMG conduction model was formulated for reverse-estimation of muscle activities using EMG signals obtained with multi surface electrodes. The optimization process was calculated using sequential quadratic programming by comparing the estimated EMG values from the model with the measured values. The individual muscle activities in the deep region were estimated and used to produce an EMG tomographic image. For validation of the method, isometric contractions of finger muscles were examined for three subjects, applying a flexion load (4.9, 7.4 and 9.8 N) to the proximal interphalangeal joint of the middle finger. EMG signals in the forearm were recorded during the tasks using multiple surface electrodes, which were bound around the subject's forearm. The EMG-CT method illustrates the distribution of muscle activities within the forearm. The change in amplitude and area of activated muscles can be observed. The normalized muscle activities of all three subjects appear to increase monotonically with increases in the load. Kinesiologically, this method was able to estimate individual muscle activation values and could provide a novel tool for studying hand function and development of an examination for evaluating rehabilitation. Copyright © 2014 Elsevier Ltd. All rights reserved.

  19. Emg Signal Analysis of Healthy and Neuropathic Individuals

    Science.gov (United States)

    Gupta, Ashutosh; Sayed, Tabassum; Garg, Ridhi; Shreyam, Richa

    2017-08-01

    Electromyography is a method to evaluate levels of muscle activity. When a muscle contracts, an action potential is generated and this circulates along the muscular fibers. In electromyography, electrodes are connected to the skin and the electrical activity of muscles is measured and graph is plotted. The surface EMG signals picked up during the muscular activity are interfaced with a system. The EMG signals from individual suffering from Neuropathy and healthy individual, so obtained, are processed and analyzed using signal processing techniques. This project includes the investigation and interpretation of EMG signals of healthy and Neuropathic individuals using MATLAB. The prospective use of this study is in developing the prosthetic device for the people with Neuropathic disability.

  20. Predicting 3D lip shapes using facial surface EMG.

    Directory of Open Access Journals (Sweden)

    Merijn Eskes

    Full Text Available The aim of this study is to prove that facial surface electromyography (sEMG conveys sufficient information to predict 3D lip shapes. High sEMG predictive accuracy implies we could train a neural control model for activation of biomechanical models by simultaneously recording sEMG signals and their associated motions.With a stereo camera set-up, we recorded 3D lip shapes and simultaneously performed sEMG measurements of the facial muscles, applying principal component analysis (PCA and a modified general regression neural network (GRNN to link the sEMG measurements to 3D lip shapes. To test reproducibility, we conducted our experiment on five volunteers, evaluating several sEMG features and window lengths in unipolar and bipolar configurations in search of the optimal settings for facial sEMG.The errors of the two methods were comparable. We managed to predict 3D lip shapes with a mean accuracy of 2.76 mm when using the PCA method and 2.78 mm when using modified GRNN. Whereas performance improved with shorter window lengths, feature type and configuration had little influence.

  1. An artificial EMG generation model based on signal-dependent noise and related application to motion classification.

    Science.gov (United States)

    Furui, Akira; Hayashi, Hideaki; Nakamura, Go; Chin, Takaaki; Tsuji, Toshio

    2017-01-01

    This paper proposes an artificial electromyogram (EMG) signal generation model based on signal-dependent noise, which has been ignored in existing methods, by introducing the stochastic construction of the EMG signals. In the proposed model, an EMG signal variance value is first generated from a probability distribution with a shape determined by a commanded muscle force and signal-dependent noise. Artificial EMG signals are then generated from the associated Gaussian distribution with a zero mean and the generated variance. This facilitates representation of artificial EMG signals with signal-dependent noise superimposed according to the muscle activation levels. The frequency characteristics of the EMG signals are also simulated via a shaping filter with parameters determined by an autoregressive model. An estimation method to determine EMG variance distribution using rectified and smoothed EMG signals, thereby allowing model parameter estimation with a small number of samples, is also incorporated in the proposed model. Moreover, the prediction of variance distribution with strong muscle contraction from EMG signals with low muscle contraction and related artificial EMG generation are also described. The results of experiments conducted, in which the reproduction capability of the proposed model was evaluated through comparison with measured EMG signals in terms of amplitude, frequency content, and EMG distribution demonstrate that the proposed model can reproduce the features of measured EMG signals. Further, utilizing the generated EMG signals as training data for a neural network resulted in the classification of upper limb motion with a higher precision than by learning from only measured EMG signals. This indicates that the proposed model is also applicable to motion classification.

  2. An artificial EMG generation model based on signal-dependent noise and related application to motion classification

    Science.gov (United States)

    Hayashi, Hideaki; Nakamura, Go; Chin, Takaaki; Tsuji, Toshio

    2017-01-01

    This paper proposes an artificial electromyogram (EMG) signal generation model based on signal-dependent noise, which has been ignored in existing methods, by introducing the stochastic construction of the EMG signals. In the proposed model, an EMG signal variance value is first generated from a probability distribution with a shape determined by a commanded muscle force and signal-dependent noise. Artificial EMG signals are then generated from the associated Gaussian distribution with a zero mean and the generated variance. This facilitates representation of artificial EMG signals with signal-dependent noise superimposed according to the muscle activation levels. The frequency characteristics of the EMG signals are also simulated via a shaping filter with parameters determined by an autoregressive model. An estimation method to determine EMG variance distribution using rectified and smoothed EMG signals, thereby allowing model parameter estimation with a small number of samples, is also incorporated in the proposed model. Moreover, the prediction of variance distribution with strong muscle contraction from EMG signals with low muscle contraction and related artificial EMG generation are also described. The results of experiments conducted, in which the reproduction capability of the proposed model was evaluated through comparison with measured EMG signals in terms of amplitude, frequency content, and EMG distribution demonstrate that the proposed model can reproduce the features of measured EMG signals. Further, utilizing the generated EMG signals as training data for a neural network resulted in the classification of upper limb motion with a higher precision than by learning from only measured EMG signals. This indicates that the proposed model is also applicable to motion classification. PMID:28640883

  3. Kinematical and EMG-classifications of a fencing attack.

    Science.gov (United States)

    Frère, J; Göpfert, B; Nüesch, C; Huber, C; Fischer, M; Wirz, D; Friederich, N F

    2011-01-01

    8 expert fencers were studied with a 3-dimensional motion analysis system. Each subject performed 10 flèche attacks toward a standardized target. Surface electromyography signals (EMG) were recorded of the deltoid pars clavicularis, infraspinatus and triceps brachii caput laterale muscles of the weapon arm. The recorded EMGs were averaged using EMG wavelet-transformation software. 4 phases were defined based on the arm kinematics and used to classify fencers into 2 groups. A first group of 4 fencers showed an early maximal elbow extension (Early MEE) whereas the second group presented a late maximal elbow extension (Late MEE). 2 EMG-classifications were based on this kinematical classification, one in the time-domain and the other in the frequency-domain by using the spherical classification. The time-domain EMG-classification showed a significantly ( P=0.03) higher normalized deltoid intensity for the Early MEE group (91 ± 18%) than the Late MEE group (36 ± 13%) in the attack phase. The spherical classification revealed that the activity of all the muscles was significantly classified (recognition rate 75%, P=0.04) between the 2 groups. This study of EMG and kinematics of the weapon upper limb in fencing proposes several classifications, which implies a relationship between kinematic strategies, muscular activations and fencing success. © Georg Thieme Verlag KG Stuttgart · New York.

  4. The extraction of neural strategies from the surface EMG: an update

    Science.gov (United States)

    Merletti, Roberto; Enoka, Roger M.

    2014-01-01

    A surface EMG signal represents the linear transformation of motor neuron discharge times by the compound action potentials of the innervated muscle fibers and is often used as a source of information about neural activation of muscle. However, retrieving the embedded neural code from a surface EMG signal is extremely challenging. Most studies use indirect approaches in which selected features of the signal are interpreted as indicating certain characteristics of the neural code. These indirect associations are constrained by limitations that have been detailed previously (Farina D, Merletti R, Enoka RM. J Appl Physiol 96: 1486–1495, 2004) and are generally difficult to overcome. In an update on these issues, the current review extends the discussion to EMG-based coherence methods for assessing neural connectivity. We focus first on EMG amplitude cancellation, which intrinsically limits the association between EMG amplitude and the intensity of the neural activation and then discuss the limitations of coherence methods (EEG-EMG, EMG-EMG) as a way to assess the strength of the transmission of synaptic inputs into trains of motor unit action potentials. The debated influence of rectification on EMG spectral analysis and coherence measures is also discussed. Alternatively, there have been a number of attempts to identify the neural information directly by decomposing surface EMG signals into the discharge times of motor unit action potentials. The application of this approach is extremely powerful, but validation remains a central issue. PMID:25277737

  5. The extraction of neural strategies from the surface EMG: an update.

    Science.gov (United States)

    Farina, Dario; Merletti, Roberto; Enoka, Roger M

    2014-12-01

    A surface EMG signal represents the linear transformation of motor neuron discharge times by the compound action potentials of the innervated muscle fibers and is often used as a source of information about neural activation of muscle. However, retrieving the embedded neural code from a surface EMG signal is extremely challenging. Most studies use indirect approaches in which selected features of the signal are interpreted as indicating certain characteristics of the neural code. These indirect associations are constrained by limitations that have been detailed previously (Farina D, Merletti R, Enoka RM. J Appl Physiol 96: 1486-1495, 2004) and are generally difficult to overcome. In an update on these issues, the current review extends the discussion to EMG-based coherence methods for assessing neural connectivity. We focus first on EMG amplitude cancellation, which intrinsically limits the association between EMG amplitude and the intensity of the neural activation and then discuss the limitations of coherence methods (EEG-EMG, EMG-EMG) as a way to assess the strength of the transmission of synaptic inputs into trains of motor unit action potentials. The debated influence of rectification on EMG spectral analysis and coherence measures is also discussed. Alternatively, there have been a number of attempts to identify the neural information directly by decomposing surface EMG signals into the discharge times of motor unit action potentials. The application of this approach is extremely powerful, but validation remains a central issue. Copyright © 2014 the American Physiological Society.

  6. The influence of mental fatigue on facial EMG activity during a simulated workday

    NARCIS (Netherlands)

    Veldhuizen, I.J.T.; Gaillard, A.W.K.; Vries, J. de

    2003-01-01

    The present study investigated whether facial EMG measures are sensitive to the effects of fatigue. EMG activity of the corrugator and frontalis muscles was recorded during and after a simulated workday. Fatigue was evaluated in four ways: (a) the building up of fatigue effects during the workday,

  7. Effect of Vibration Training on Anaerobic Power and Quardroceps Surface EMG in Long Jumpers

    Science.gov (United States)

    Liu, Bin; Luo, Jiong

    2015-01-01

    Objective: To explore the anaerobic power and surface EMG (sEMG) of quardrocep muscle in lower extremities after single vibration training intervention. Methods: 8 excellent male long jumpers voluntarily participated in this study. Four intervention modes were devised, including high frequency high amplitude (HFHA,30Hz,6mm), low frequency low…

  8. Lack of effect of acupuncture on electromyographic (EMG) activity--a randomised controlled trial in healthy volunteers

    National Research Council Canada - National Science Library

    Tough, Liz

    2006-01-01

    Acupuncture is used clinically to treat muscle spasticity and flaccidity. Claims have been made that acupuncture can affect muscle EMG activity, though there is some doubt about the reliability of these studies...

  9. Peak and average rectified EMG measures: which method of data reduction should be used for assessing core training exercises?

    Science.gov (United States)

    Hibbs, A E; Thompson, K G; French, D N; Hodgson, D; Spears, I R

    2011-02-01

    Core strengthening and stability exercises are fundamental for any conditioning training program. Although surface electromyography (sEMG) is used to quantify muscle activity there is a lack of research using this method to investigate the core musculature and core stability. Two types of data reduction are commonly used for sEMG; peak and average rectified EMG methods. Peak EMG has been infrequently reported in the literature with regard to the assessment of core training while even fewer studies have incorporated average rectified EMG data (ARV). The aim of the study was to establish the repeatability of peak and average rectified EMG data during core training exercises and their interrelationship. Ten male highly trained athletes (inter-subject repeatability group; age, 18 ± 1.2 years; height, 176.5 ± 3.2 cm; body mass, 71 ± 4.5 kg) and one female highly trained athlete (intra-subject repeatability group; age; 27 years old; height; 180 cm; weight; 53 kg) performed five maximal voluntary isometric contractions (MVIC) and five core exercises, chosen to represent a range of movement and muscle recruitment patterns. Peak EMG and ARV EMG were calculated for eight core muscles (rectus abdominis, RA; external oblique, EO; internal oblique, IO; multifidis, MF; latissimus dorsi, LD; longissimus, LG; gluteus maximus, GM; rectus femoris, RF) using sEMG. Average coefficient of variation (CV%) for peak EMG across all the exercises and muscles was 45%. This is in comparison to 35% for the ARV method, which was found to be a significant difference (Pexercise. Analysis of the inter-subject and intra-subject CV% values suggest that these exercises and muscles are sufficiently repeatable using sEMG. Five muscles were highly correlated (R>0.70; RA, EO, MF, GM, LG) between peak and ARV EMG suggesting, that for these core muscles, the two methods provide a similar evaluation of muscle activity. However, for other muscles (IO, RF, LD) the relationship was found to range from poor

  10. Normative EMG values during REM sleep for the diagnosis of REM sleep behavior disorder.

    Science.gov (United States)

    Frauscher, Birgit; Iranzo, Alex; Gaig, Carles; Gschliesser, Viola; Guaita, Marc; Raffelseder, Verena; Ehrmann, Laura; Sola, Nuria; Salamero, Manel; Tolosa, Eduardo; Poewe, Werner; Santamaria, Joan; Högl, Birgit

    2012-06-01

    Correct diagnosis of rapid eye movement sleep behavior disorder (RBD) is important because it can be the first manifestation of a neurodegenerative disease, it may lead to serious injury, and it is a well-treatable disorder. We evaluated the electromyographic (EMG) activity in the Sleep Innsbruck Barcelona (SINBAR) montage (mentalis, flexor digitorum superficialis, extensor digitorum brevis) and other muscles to obtain normative values for the correct diagnosis of RBD for clinical practice. Two university hospital sleep disorder centers. Thirty RBD patients (15 idiopathic [iRBD], 15 with Parkinson disease [PD]) and 30 matched controls recruited from patients with effectively treated sleep related breathing disorders. Not applicable. Participants underwent video-polysomnography, including registration of 11 body muscles. Tonic, phasic, and "any" (any type of EMG activity, irrespective of whether it consisted of tonic, phasic or a combination of both) EMG activity was blindly quantified for each muscle. When choosing a specificity of 100%, the 3-sec miniepoch cutoff for a diagnosis of RBD was 18% for "any" EMG activity in the mentalis muscle (area under the curve [AUC] 0.990). Discriminative power was higher in upper limb (100% specificity, AUC 0.987-9.997) than in lower limb muscles (100% specificity, AUC 0.813-0.852). The combination of "any" EMG activity in the mentalis muscle with both phasic flexor digitorum superficialis muscles yielded a cutoff of 32% (AUC 0.998) for patients with iRBD and with PD-RBD. For the diagnosis of iRBD and RBD associated with PD, we recommend a polysomnographic montage quantifying "any" (any type of EMG activity, irrespective of whether it consisted of tonic, phasic or a combination of both) EMG activity in the mentalis muscle and phasic EMG activity in the right and left flexor digitorum superficialis muscles in the upper limbs with a cutoff of 32%, when using 3-sec miniepochs.

  11. Knowledge of electromyography (EMG) in patients undergoing EMG examinations.

    Science.gov (United States)

    Mondelli, Mauro; Aretini, Alessandro; Greco, Giuseppe

    2014-01-01

    The aim of this study was to evaluate knowledge of electromyography (EMG) in patients undergoing the procedure. In one year, 1,586 consecutive patients (mean age 56 years; 58.8% women) were admitted to two EMG labs to undergo EMG for the first time. The patients found to be "informed" about the how an EMG examination is performed and about the purpose of EMG numbered 448 (28.2%), while those found to be "informed" only about the manner of its execution or only about its purpose numbered 161 (10.2%) and 151 (9.5%), respectively. The remaining 826 (52.1%) patients had either no information, or the information they had was very poor or incorrect (this was particularly true if they had been consulting websites). Being "informed" was associated with level of education (high), type of referring physician (specialist) and with an appropriate referral diagnosis specified in the EMG request. The quality of patient information on EMG was found to be very poor and could be improved. Physicians referring patients for EMG examinations, especially general practitioners, should assume primary responsibility for patient education and counseling in this field.

  12. Knowledge of electromyography (EMG) in patients undergoing EMG examinations

    Science.gov (United States)

    Mondelli, Mauro; Aretini, Alessandro; Greco, Giuseppe

    2014-01-01

    Summary The aim of this study was to evaluate knowledge of electromyography (EMG) in patients undergoing the procedure. In one year, 1,586 consecutive patients (mean age 56 years; 58.8% women) were admitted to two EMG labs to undergo EMG for the first time. The patients found to be “informed” about the how an EMG examination is performed and about the purpose of EMG numbered 448 (28.2%), while those found to be “informed” only about the manner of its execution or only about its purpose numbered 161 (10.2%) and 151 (9.5%), respectively. The remaining 826 (52.1%) patients had either no information, or the information they had was very poor or incorrect (this was particularly true if they had been consulting websites). Being “informed” was associated with level of education (high), type of referring physician (specialist) and with an appropriate referral diagnosis specified in the EMG request. The quality of patient information on EMG was found to be very poor and could be improved. Physicians referring patients for EMG examinations, especially general practitioners, should assume primary responsibility for patient education and counseling in this field. PMID:25473740

  13. Natural mediotrusive contact: does it affect the masticatory and neck EMG activity during tooth grinding?

    Science.gov (United States)

    Fuentes, Aler D; Martin, Conchita; Bull, Ricardo; Santander, Hugo; Gutiérrez, Mario F; Miralles, Rodolfo

    2016-07-01

    There is scarce knowledge regarding the influence of a natural mediotrusive contact on mandibular and cervical muscular activity. The purpose of this study was to analyze the EMG activity of the anterior temporalis (AT) and sternocleidomastoid (SCM) muscles during awake grinding in healthy subjects with or without a natural mediotrusive occlusal contact. Fifteen subjects with natural mediotrusive occlusal contact (Group 1) and 15 subjects without natural mediotrusive occlusal contact (Group 2) participated. Bilateral surface EMG activity of AT and SCM muscles was recorded during unilateral eccentric or concentric tooth grinding tasks. EMG activity was normalized against the activity recorded during maximal voluntary clenching in intercuspal position (IP) for AT muscles and during maximal intentional isometric head-neck rotation to each side, for SCM muscles. EMG activity of AT and SCM muscles showed no statistical difference between groups. EMG activity of AT muscle was higher in the working side (WS) than in the non-WS (NWS) in Group 1 during concentric grinding (0.492 vs 0.331, p = 0.047), whereas no difference was observed in Group 2. EMG activity of SCM was similar between working and NWSs in both groups and tasks. Asymmetry indexes (AIs) were not significantly different between groups. These findings in healthy subjects support the assumption that during awake tooth grinding, central nerve control predominates over peripheral inputs, and reinforce the idea of a functional link between the motor-neuron pools that control jaw and neck muscles.

  14. Estimation of Upper Limb Joint Angle Using Surface EMG Signal

    Directory of Open Access Journals (Sweden)

    Yee Mon Aung

    2013-10-01

    Full Text Available In the development of robot-assisted rehabilitation systems for upper limb rehabilitation therapy, human electromyogram (EMG is widely used due to its ability to detect the user intended motion. EMG is one kind of biological signal that can be recorded to evaluate the performance of skeletal muscles by means of a sensor electrode. Based on recorded EMG signals, user intended motion could be extracted via estimation of joint torque, force or angle. Therefore, this estimation becomes one of the most important factors to achieve accurate user intended motion. In this paper, an upper limb joint angle estimation methodology is proposed. A back propagation neural network (BPNN is developed to estimate the shoulder and elbow joint angles from the recorded EMG signals. A Virtual Human Model (VHM is also developed and integrated with BPNN to perform the simulation of the estimated angle. The relationships between sEMG signals and upper limb movements are observed in this paper. The effectiveness of our developments is evaluated with four healthy subjects and a VHM simulation. The results show that the methodology can be used in the estimation of joint angles based on EMG.

  15. Specialized Nerve Tests: EMG, NCV and SSEP

    Science.gov (United States)

    ... BLOG FIND A SPECIALIST Treatments Specialized Nerve Tests: EMG, NCV and SSEP Ajay Jawahar MD Ajay Jawahar ... these techniques in the following sections. What is EMG? EMG, or Electromyography is a technique for evaluating ...

  16. Frequency analysis of EMG activity in patients with idiopathic torticollis

    NARCIS (Netherlands)

    Tijssen, MAJ; Marsden, JF; Brown, P

    The pathophysiology of idiopathic dystonic torticollis is unclear and there is no simple test that confirms the diagnosis and excludes a psychogenic or voluntary torticollis in individual patients. We recorded EMG activity in the sternocleidomastoid (SCM) and splenius capitis (SPL) muscles of eight

  17. Analysis of the sEMG/force relationship using HD-sEMG technique and data fusion: A simulation study.

    Science.gov (United States)

    Al Harrach, Mariam; Carriou, Vincent; Boudaoud, Sofiane; Laforet, Jeremy; Marin, Frederic

    2017-04-01

    The relationship between the surface Electromyogram (sEMG) signal and the force of an individual muscle is still ambiguous due to the complexity of experimental evaluation. However, understanding this relationship should be useful for the assessment of neuromuscular system in healthy and pathological contexts. In this study, we present a global investigation of the factors governing the shape of this relationship. Accordingly, we conducted a focused sensitivity analysis of the sEMG/force relationship form with respect to neural, functional and physiological parameters variation. For this purpose, we used a fast generation cylindrical model for the simulation of an 8×8 High Density-sEMG (HD-sEMG) grid and a twitch based force model for the muscle force generation. The HD-sEMG signals as well as the corresponding force signals were simulated in isometric non-fatiguing conditions and were based on the Biceps Brachii (BB) muscle properties. A total of 10 isometric constant contractions of 5s were simulated for each configuration of parameters. The Root Mean Squared (RMS) value was computed in order to quantify the sEMG amplitude. Then, an image segmentation method was used for data fusion of the 8×8 RMS maps. In addition, a comparative study between recent modeling propositions and the model proposed in this study is presented. The evaluation was made by computing the Normalized Root Mean Squared Error (NRMSE) of their fitting to the simulated relationship functions. Our results indicated that the relationship between the RMS (mV) and muscle force (N) can be modeled using a 3rd degree polynomial equation. Moreover, it appears that the obtained coefficients are patient-specific and dependent on physiological, anatomical and neural parameters. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Generalization of EMG biofeedback training.

    Science.gov (United States)

    Poppen, R; Hanson, H B; Ip, S M

    1988-09-01

    Five young adults received audio biofeedback training to reduce trapezius EMG levels while they engaged in reading in an office, seated at a table. A multiple-baseline-across subjects design was employed in two separate studies. After training, all subjects demonstrated reduced EMG levels while reading in a home or library setting. The first study suggested that subjects reduced EMG levels by minimizing movements and altering their postures; the second study systematically demonstrated changes in such behavior, which was correlated with EMG levels. The data provide evidence that EMG biofeedback resulted in response generalization across several motoric classes, and in stimulus generalization from the training setting to the natural environment. The importance of assessing generalization is discussed.

  19. Surface Laplacian of scalp electrical signals and independent component analysis resolve EMG contamination of electroencephalogram.

    Science.gov (United States)

    Fitzgibbon, S P; DeLosAngeles, D; Lewis, T W; Powers, D M W; Whitham, E M; Willoughby, J O; Pope, K J

    2015-09-01

    The serious impact of electromyogram (EMG) contamination of electroencephalogram (EEG) is well recognised. The objective of this research is to demonstrate that combining independent component analysis with the surface Laplacian can eliminate EMG contamination of the EEG, and to validate that this processing does not degrade expected neurogenic signals. The method involves sequential application of ICA, using a manual procedure to identify and discard EMG components, followed by the surface Laplacian. The extent of decontamination is quantified by comparing processed EEG with EMG-free data that was recorded during pharmacologically induced neuromuscular paralysis. The combination of the ICA procedure and the surface Laplacian, with a flexible spherical spline, results in a strong suppression of EMG contamination at all scalp sites and frequencies. Furthermore, the ICA and surface Laplacian procedure does not impair the detection of well-known, cerebral responses; alpha activity with eyes-closed; ERP components (N1, P2) in response to an auditory oddball task; and steady state responses to photic and auditory stimulation. Finally, more flexible spherical splines increase the suppression of EMG by the surface Laplacian. We postulate this is due to ICA enabling the removal of local muscle sources of EMG contamination and the Laplacian transform being insensitive to distant (postural) muscle EMG contamination. Copyright © 2014 Elsevier B.V. All rights reserved.

  20. Validating the EMG(FT) from a single incremental cycling test.

    Science.gov (United States)

    Briscoe, M J; Forgach, M S; Trifan, E; Malek, M H

    2014-06-01

    The purposes of this study were to (1) identify the EMG(FT) from a single incremental cycle ergometry test and (2) validate this fatigue threshold by having participants perform constant workload rides at 70, 100 and 130% of the estimated EMG(FT). 11 healthy college-age participants performed incremental cycle ergometry on the initial visit. The EMG amplitude was recorded from the vastus lateralis muscle for each power output and fitted with linear regression which provided the estimated EMG(FT). In subsequent visits, participants exercised at 3 percentages of their EMG(FT) with the EMG amplitude recorded for each condition. The results indicated no significant (p>0.05) increases in EMG amplitude vs. time for the 70% and 100% workloads, respectively. In addition, the participants were able to maintain these exercise intensities for over 40 min. For the 130% workload, however, EMG amplitude vs. time increased significantly (pEMG(FT) estimated from a single incremental cycle ergometry test is a valid measure of neuromuscular fatigue and may potentially be useful in assessing the efficacy of rehabilitative interventions. © Georg Thieme Verlag KG Stuttgart · New York.

  1. High-pass filtering to remove electrocardiographic interference from torso EMG recordings.

    Science.gov (United States)

    Redfern, M; Hughes, R; Chaffin, D

    1993-01-01

    Removal of electrocardiographic (ECG) contamination of electromyographic (EMG) signals from torso muscles is often attempted by high-pass filtering. This study investigated the effects of the cut-off frequency used in this high-pass filtering technique on the resulting EMG signal. Surface EMGs were recorded on five subjects from the rectus abdominis, external oblique, and erector spinae muscles. These signals were then digitally high-pass filtered at cut-off frequencies of 10, 30, and 60 Hz. Integration and power analyses of the filtered EMGs were subsequently performed. It was found that an increase in the cut-off frequency affects the integrated EMG signal by (1) reducing the ECG contamination, (2) decreasing the amplitude, and (3) smoothing the signal. It was concluded that the use of a high-pass filter is effective in reducing ECG interference in integrated EMG recordings, and a cut-off frequency of approximately 30 Hz was optimal. Electromyographic recordings of torso muscles are often used in the development of low-back biomechanical models. Unfortunately, these recordings are usually contaminated by electrocardiographic interference. High-pass filtering methods are sometimes used to diminish the influence of ECG from surface EMGs; however, the effects of these filters on the recorded and processed EMG have not been reported. The findings show that high-pass filtering is effective in reducing ECG contamination and motion artefact from integrated EMGs when the appropriate cut-off frequency is used. Inappropriate cut-off frequencies lead to either incomplete ECG removal or excess filtering of the EMG signal. Copyright © 1993. Published by Elsevier Ltd.

  2. [Electromyography (EMG) and neurography in patients with severe neuromuscular diseases].

    Science.gov (United States)

    Løseth, Sissel; Torbergsen, Torberg

    2013-01-22

    Many neuromuscular diseases are potentially severe, and EMG and neurography are methods used in the assessment of these conditions. The article is based on the authors' knowledge and experience, with special emphasis on the use of these methods in the assessment of severe diseases affecting striated muscle and peripheral nerves. A PubMed search was performed with the cut-off fifteen years back in time, and in addition a discretionary selection was made of articles known to the authors. EMG is the most valuable method for assessing myopathy, and neurography provides most information about neuropathy, but the methods are complementary. These examinations are the most sensitive for diagnosing some conditions (for example myasthaenia) A high level of expertise is necessary for diagnosing these conditions. EMG and neurography are important and often necessary means of assessing patients with severe neuromuscular disease.

  3. A surface EMG test tool to measure proportional prosthetic control.

    Science.gov (United States)

    Sturma, Agnes; Roche, Aidan D; Göbel, Peter; Herceg, Malvina; Ge, Nan; Fialka-Moser, Veronika; Aszmann, Oskar

    2015-06-01

    In upper limb amputees, prosthetic control training is recommended before and after fitting. During rehabilitation, the focus is on selective proportional control signals. For functional monitoring, many different tests are available. None can be used in the early phase of training. However, an early assessment is needed to judge if a patient has the potential to control a certain prosthetic set-up. This early analysis will determine if further training is needed or if other strategies would be more appropriate. Presented here is a tool that is capable of predicting achievable function in voluntary EMG control. This tool is applicable to individual muscle groups to support preparation of training and fitting. In four of five patients, the sEMG test tool accurately predicted the suitability for further myoelectric training based on SHAP outcome measures. (P1: "Poor" function in the sEMG test tool corresponded to 54/100 in the SHAP test; P2: Good: 85; P3: Good: 81; P4: Average: 78). One patient scored well during sEMG testing, but was unmotivated during SHAP testing. (Good: 50) Therefore, the surface EMG test tool may predict achievable control skills to a high extent, validated with the SHAP, but requires further clinical testing to validate this technique.

  4. What do facial expressions of emotion express in young children? The relationship between facial display and EMG measures

    OpenAIRE

    Michela Balconi; Giovanni Lecci; Verdiana Trapletti

    2014-01-01

    The present paper explored the relationship between emotional facial response and electromyographic modulation in children when they observe facial expression of emotions. Facial responsiveness (evaluated by arousal and valence ratings) and psychophysiological correlates (facial electromyography, EMG) were analyzed when children looked at six facial expressions of emotions (happiness, anger, fear, sadness, surprise and disgust). About EMG measure, corrugator and zygomatic muscle activity was ...

  5. Objective models of EMG signals for cyclic processes such as a human gait

    Science.gov (United States)

    Babska, Luiza; Selegrat, Monika; Dusza, Jacek J.

    2016-09-01

    EMG signals are small potentials appearing at the surface of human skin during muscle work. They arise due to changes in the physiological state of cell membranes in the muscle fibers. They are characterized by a relatively low frequency range (500 Hz) and a low amplitude signal (of the order of μV), making it difficult to record. Raw EMG signal is inherently random shape. However we can distinguish certain features related to the activation of the muscles of a deterministic or quasi-deterministic associated with the movement and its parametric description. Objective models of EMG signals were created on the base of actual data obtained from the VICON system installed at the University of Physical Education in Warsaw. The object of research (healthy woman) moved repeatedly after a fixed track. On her body 35 reflective markers to record the gait kinematics and 8 electrodes to record EMG signals were placed. We obtained research data included more than 1,000 EMG signals synchronized with the phases of gait. Test result of the work is an algorithm for obtaining the average EMG signal received from the multiple registration gait cycles carried out in the same reproducible conditions. The method described in the article is essentially a pre-finding measurement data from the two quasi-synchronous signals at different sampling frequencies for further processing. This signal is characterized by a significant reduction of high frequency noise and emphasis on the specific characteristics of individual records found in muscle activity.

  6. Comparison of lumbar and abdominal muscle activation during two types of golf swing: An EMG analysis. (Comparación de la activación muscular abdominal y lumbar en la realización de dos tipos de swing en Golf: Un análisis electromiográfico.

    Directory of Open Access Journals (Sweden)

    Sandhu Jaspal Singh

    2008-07-01

    Full Text Available AbstractGolf is a popular sport and golf swing is a complex movement which requires a coordinated sequence of muscle activity. Two types of golf swing exists i.e. “Classical” and “Modern”. Classical swing differs from modern swing in several respects, which are important when considering their effects on the lower back. The present study compared muscle activation amplitudes in the trunk region of golfers during two different types of golf swing. 22 golfers (21.5 years ±3.4 were instructed to perform modern and classical golf swing and surface EMG activity was recorded from external oblique (E.O., internal oblique (I.O., and erector spinae (E.S. muscles of both sides. Results showed muscle activity of right and left side of E.O. and I.O. to be lower in modern swing than classical swing (significant difference p menor que 0.05 in downswing and impact phase, whereas it is higher for both sides E.S. in modern swing. The E.S. muscle activity during follow-through phase was significantly higher (p menor que 0.05 in modern swing compared to classical swing. Significant differences in E.S. and other muscles activity suggest inappropriate recruitment of these muscles in golfers during the modern swing. EMG evidence proposes that the modern golf swing produces more extension forces in the lower back compared with the forces of classical swing.Resumen El Golf es un deporte popular y el swing en golf es un movimiento complejo que reclama una secuencia coordinada de movimientos. Existen dos tipos de swing: el clásico y el moderno. El Clásico se diferencia del Moderno en varios aspectos que son importantes cuando se consideran sus efectos en la parte inferior de la espalda. Este estudio comparó la amplitud de la activación muscular en el tronco de los golfistas al realizar los dos tipos de swing. Veintidos jugadores de golf (21.5 años ±3.4 fueron instruidos para realizar el swing moderno y clásico, tomándose la actividad muscular (actividad

  7. Long-term surface EMG monitoring using K-means clustering and compressive sensing

    Science.gov (United States)

    Balouchestani, Mohammadreza; Krishnan, Sridhar

    2015-05-01

    In this work, we present an advanced K-means clustering algorithm based on Compressed Sensing theory (CS) in combination with the K-Singular Value Decomposition (K-SVD) method for Clustering of long-term recording of surface Electromyography (sEMG) signals. The long-term monitoring of sEMG signals aims at recording of the electrical activity produced by muscles which are very useful procedure for treatment and diagnostic purposes as well as for detection of various pathologies. The proposed algorithm is examined for three scenarios of sEMG signals including healthy person (sEMG-Healthy), a patient with myopathy (sEMG-Myopathy), and a patient with neuropathy (sEMG-Neuropathr), respectively. The proposed algorithm can easily scan large sEMG datasets of long-term sEMG recording. We test the proposed algorithm with Principal Component Analysis (PCA) and Linear Correlation Coefficient (LCC) dimensionality reduction methods. Then, the output of the proposed algorithm is fed to K-Nearest Neighbours (K-NN) and Probabilistic Neural Network (PNN) classifiers in order to calclute the clustering performance. The proposed algorithm achieves a classification accuracy of 99.22%. This ability allows reducing 17% of Average Classification Error (ACE), 9% of Training Error (TE), and 18% of Root Mean Square Error (RMSE). The proposed algorithm also reduces 14% clustering energy consumption compared to the existing K-Means clustering algorithm.

  8. EMG biofeedback training in adult attention-deficit/hyperactivity disorder: An active (control) training?

    Science.gov (United States)

    Barth, Beatrix; Mayer, Kerstin; Strehl, Ute; Fallgatter, Andreas J; Ehlis, Ann-Christine

    2017-06-30

    The present study aimed at revealing neurophysiological effects induced by electromyography (EMG) based biofeedback, considered as a semi-active control condition in neurofeedback studies, in adult attention-deficit/hyperactivity disorder (ADHD) patients. 20 adult ADHD patients trained their muscle activity in the left and right supraspinatus muscle over the course of 30 EMG biofeedback sessions. Changes induced by the EMG feedback were evaluated at a clinical and neurophysiological level; additionally, the relation between changes in EEG activity recorded at the vertex over the training course and changes of symptom severity over the treatment course were assessed in order to investigate the mechanisms underlying clinical effects of EMG biofeedback. Participants showed significant behavioral improvements on a self-rating scale. There was a significant increase in alpha power, but no significant changes in the delta frequency range; changes in the theta and beta frequency range were not significant after adjustment for multiple comparisons. No statistically significant correlation was found between changes in EEG frequency bands and changes in ADHD symptoms. The current results assessed by means of a single-electrode EEG constitute a starting point regarding a clearer understanding of mechanisms underlying clinical effects of EMG biofeedback. Although we did not reveal systematic effects induced by EMG feedback on brain activity it remains an open question whether EMG biofeedback induces changes in brain regions or parameters we did not gather in the present study (e.g. motor cortex). Copyright © 2017 Elsevier B.V. All rights reserved.

  9. When EMG contamination does not necessarily hide high-frequency EEG: scalp electrical recordings before and after Dysport injections.

    Science.gov (United States)

    Boytsova, Julia A; Danko, Sergey G; Medvedev, Svyatoslav V

    2016-11-01

    The main aim of the present study was to investigate effects of partial reductions of electromyogram (EMG) on high-frequency scalp electroencephalogram (EEG) at rest and during performance of certain cognitive tasks. Nineteen healthy women performed the same cognitive tasks before and after cosmetic injections of Dysport in certain sites of facial muscles. Scalp EEG and EMG were recorded. Impact of Dysport injections on changes of spectral power in β2 and low γ frequency ranges (18-40 Hz) in EEG and EMG derivations was investigated. Also changes of spectral power in EEG and EMG derivations during comparisons of different cognitive states were calculated before and after Dysport injections separately. Dysport injections led to EMG decreases in facial muscles around the injection zones and also led to reductions of power of electric processes in scalp derivations. Along with it results of EEG power comparisons between the pairs of the cognitive states were qualitatively similar before and after Dysport injections. These facts to all appearance demonstrate that though scalp EEGs in the range above 15-40 Hz are contaminated by EMG, in certain experimental situations EMG contamination does not preclude qualitative detections of electroencephalographic correlates of mental activities in β2 and low γ frequency ranges. Parallel EEG and EMG registrations can help not to overestimate EMG contamination in psychophysiological EEG studies.

  10. Effect of vibrotactile feedback on an EMG-based proportional cursor control system.

    Science.gov (United States)

    Li, Shunchong; Chen, Xingyu; Zhang, Dingguo; Sheng, Xinjun; Zhu, Xiangyang

    2013-01-01

    Surface electromyography (sEMG) has been introduced into the bio-mechatronics systems, however, most of them are lack of the sensory feedback. In this paper, the effect of vibrotactile feedback for a myoelectric cursor control system is investigated quantitatively. Simultaneous and proportional control signals are extracted from EMG using a muscle synergy model. Different types of feedback including vibrotactile feedback and visual feedback are added, assessed and compared with each other. The results show that vibrotactile feedback is capable of improving the performance of EMG-based human machine interface.

  11. Úloha sestry při vyšetření EMG

    OpenAIRE

    PELEŠKOVÁ, Adéla

    2010-01-01

    The electromyography (EMG) is a technique capable of recording the electrical activity produced by skeletal muscles and examining whether nerves are sufficiently supplied. The electromyography is carried out in some neurological ambulances or EMG laboratories. Together with a practitioner, it is a nurse who has an unsubstitutable role. The epithet ``assisting{\\crqq} belongs inseparably to the nurse´s profession. Her behaviour, acting and attitude can affect {--} positively as well as negative...

  12. Reliability of MUAP properties in multi-channel array EMG recordings of trapezius and SCM

    NARCIS (Netherlands)

    Kallenberg, L.A.C.; Preece, S.; Hermens, Hermanus J.

    2007-01-01

    Muscle activity can be assessed non-invasively by means of surface electrodes places at the skin overlyin a muscle. When multiy-channel array electrodes are used, it is possible to extract motor unit action potentials (MUAP's) from the EMG signals with a segmentation approach based on the Continuous

  13. Surface EMG Recording of the Perioral Reflexes: Preliminary Observations on Stutterers and Nonstutterers.

    Science.gov (United States)

    McClean, Michael D.

    1987-01-01

    Surface electrodes were used to describe the perioral reflexes in seven stutterers and five nonstutterers and electromyographic (EMG) recordings were obtained at electrode sites associated with the orbicularis oris inferior muscle and the depressor labia inferior muscle. A difference was noted in the pattern of reflex response between the two…

  14. Time-of-Day Effects on EMG Parameters During the Wingate Test in Boys

    National Research Council Canada - National Science Library

    Souissi, Hichem; Chtourou, Hamdi; Chaouachi, Anis; Chamari, Karim; Souissi, Nizar; Amri, Mohamed

    2012-01-01

    ... (measurement of muscle power and fatigue) at 07:00 and 17:00-h on separate days. Surface EMG activity was recorded in the Vastus lateralis, rectus femoris and vastus medialis muscles throughout the test and analyzed over a 5-s span...

  15. Histamine induced airway response in pre-school children assessed by a non-invasive EMG technique

    NARCIS (Netherlands)

    Maarsingh, E. J. W.; van Eykern, LA; Sprikkelman, AB; van Aalderen, WMC

    The aim of the study was to investigate the association between surface electromyographic (EMG) activity of the diaphragm and intercostal muscles, and clinical symptoms (wheeze, cough, increased respiratory rate and prolonged expiration) during bronchial challenge testing and after administration of

  16. Supplementing biomechanical modeling with EMG analysis

    Science.gov (United States)

    Lewandowski, Beth; Jagodnik, Kathleen; Crentsil, Lawton; Humphreys, Bradley; Funk, Justin; Gallo, Christopher; Thompson, William; DeWitt, John; Perusek, Gail

    2016-01-01

    It is well established that astronauts experience musculoskeletal deconditioning when exposed to microgravity environments for long periods of time. Spaceflight exercise is used to counteract these effects, and the Advanced Resistive Exercise Device (ARED) on the International Space Station (ISS) has been effective in minimizing musculoskeletal losses. However, the exercise devices of the new exploration vehicles will have requirements of limited mass, power and volume. Because of these limitations, there is a concern that the exercise devices will not be as effective as ARED in maintaining astronaut performance. Therefore, biomechanical modeling is being performed to provide insight on whether the small Multi-Purpose Crew Vehicle (MPCV) device, which utilizes a single-strap design, will provide sufficient physiological loading to maintain musculoskeletal performance. Electromyography (EMG) data are used to supplement the biomechanical model results and to explore differences in muscle activation patterns during exercises using different loading configurations.

  17. Estimating mood variation from MPF of EMG during walking.

    Science.gov (United States)

    Kinase, Yuta; Venture, Gentiane

    2013-01-01

    The information on the mood included in behavior is classified into nonverbal information, and is included in behavior without necessarily being based on the intention of an agent. Consequently, it is considered that we can estimate the mood from the measurement of the behavior. In this work, we estimate the mood from the surface electromyogram (EMG) information of the muscles of the upper limb during walking. Identification of emotion and mood using EMG information has been done with a variety of methods until now. In addition, it is known that human walking includes information that is specific to the individual and be affected by mood. Therefore, it is thought that the EMG analysis of walking is effective in the identification of human mood. In this work, we made a subject walk in the various mood states and answer psychological tests that measure the mood. We use two types of tasks (music listening and numerical calculation) for evoking different moods. Statistical features of EMG signals are calculated using Fast Fourier Transform (FFT) and Principal Component Analysis (PCA). These statistical features are related with psychological test scores, using regression analysis. In this paper, we have shown the statistical significance of the linear model to predict the variation of mood based on the information on the variation in MPF of EMG data of the muscles of the upper limb during walking with different moods. This shows the validity of such a mapping. However, since the interpretability of the model is still low, it cannot be said that the model is able to accurately represent the mood variation. Creating a model with high accuracy is a key issue in the future.

  18. Human joint motion estimation for electromyography (EMG)-based dynamic motion control.

    Science.gov (United States)

    Zhang, Qin; Hosoda, Ryo; Venture, Gentiane

    2013-01-01

    This study aims to investigate a joint motion estimation method from Electromyography (EMG) signals during dynamic movement. In most EMG-based humanoid or prosthetics control systems, EMG features were directly or indirectly used to trigger intended motions. However, both physiological and nonphysiological factors can influence EMG characteristics during dynamic movements, resulting in subject-specific, non-stationary and crosstalk problems. Particularly, when motion velocity and/or joint torque are not constrained, joint motion estimation from EMG signals are more challenging. In this paper, we propose a joint motion estimation method based on muscle activation recorded from a pair of agonist and antagonist muscles of the joint. A linear state-space model with multi input single output is proposed to map the muscle activity to joint motion. An adaptive estimation method is proposed to train the model. The estimation performance is evaluated in performing a single elbow flexion-extension movement in two subjects. All the results in two subjects at two load levels indicate the feasibility and suitability of the proposed method in joint motion estimation. The estimation root-mean-square error is within 8.3% ∼ 10.6%, which is lower than that being reported in several previous studies. Moreover, this method is able to overcome subject-specific problem and compensate non-stationary EMG properties.

  19. Dental occlusion and body posture: a surface EMG study.

    Science.gov (United States)

    Bergamini, Maurizio; Pierleoni, Felicita; Gizdulich, Andrea; Bergamini, Carlo

    2008-01-01

    The influence between dental occlusion and body posture has been discussed in the past ten years by several authors with controversial conclusions. The objective of this study was to access, using surface electromyography (EMG), the rest activity of paired sternocleidomastoids, erectors spinae at L4 level, and soleus muscles in a group of 24 volunteer subjects (12 males, 12 females, aged 23-25 yrs) affected by sub-clinical dental malocclusions in different situations of dental occlusion. The subjects' occlusion was balanced (neuromuscularly) (registered on an acrylic wafer). Rest activity was assessed using the sEMG. The measurements were achieved on subjects while standing barefooted, before (Test 1), and 15 minutes after they wore the acrylic wafer (Test 2). The result was a significant reduction of the mean voltage for each muscle. Paired muscles were registered and the balancing rate between right and left muscles showed improvement for all the paired muscles (Wilcoxon test p occlusion with an acrylic wafer on the following paired postural muscles: sternocleidomostoid, erector spinae, and soleus.

  20. Zebrafish needle EMG: a new tool for high-throughput drug screens.

    Science.gov (United States)

    Cho, Sung-Joon; Nam, Tai-Seung; Byun, Donghak; Choi, Seok-Yong; Kim, Myeong-Kyu; Kim, Sohee

    2015-09-01

    Zebrafish models have recently been highlighted as a valuable tool in studying the molecular basis of neuromuscular diseases and developing new pharmacological treatments. Needle electromyography (EMG) is needed not only for validating transgenic zebrafish models with muscular dystrophies (MD), but also for assessing the efficacy of therapeutics. However, performing needle EMG on larval zebrafish has not been feasible due to the lack of proper EMG sensors and systems for such small animals. We introduce a new type of EMG needle electrode to measure intramuscular activities of larval zebrafish, together with a method to hold the animal in position during EMG, without anesthetization. The silicon-based needle electrode was found to be sufficiently strong and sharp to penetrate the skin and muscles of zebrafish larvae, and its shape and performance did not change after multiple insertions. With the use of the proposed needle electrode and measurement system, EMG was successfully performed on zebrafish at 30 days postfertilization (dpf) and at 5 dpf. Burst patterns and spike morphology of the recorded EMG signals were analyzed. The measured single spikes were triphasic with an initial positive deflection, which is typical for motor unit action potentials, with durations of ∼10 ms, whereas the muscle activity was silent during the anesthetized condition. These findings confirmed the capability of this system of detecting EMG signals from very small animals such as 5 dpf zebrafish. The developed EMG sensor and system are expected to become a helpful tool in validating zebrafish MD models and further developing therapeutics. Copyright © 2015 the American Physiological Society.

  1. EMG based FES for post-stroke rehabilitation

    Science.gov (United States)

    Piyus, Ceethal K.; Anjaly Cherian, V.; Nageswaran, Sharmila

    2017-11-01

    Annually, 15 million in world population experiences stroke. Nearly 9 million stroke survivors every year experience mild to severe disability. The loss of upper extremity function in stroke survivors still remains a major rehabilitation challenge. The proposed EMG Abstract—Annually, 15 million in world population experiences stroke. Nearly 9 million stroke survivors every year experience mild to severe disability. The loss of upper extremity function in stroke survivors still remains a major rehabilitation challenge. The proposed EMG based FES system can be used for effective upper limb motor re-education in post stroke upper limb rehabilitation. The governing feature of the designed system is its synchronous activation, in which the FES stimulation is dependent on the amplitude of the EMG signal acquired from the unaffected upper limb muscle of the hemiplegic patient. This proportionate operation eliminates the undesirable damage to the patient’s skin by generating stimulus in proportion to voluntary EMG signals. This feature overcomes the disadvantages of currently available manual motor re-education systems. This model can be used in home-based post stroke rehabilitation, to effectively improve the upper limb functions.

  2. EMG Processing Based Measures of Fatigue Assessment during Manual Lifting

    Science.gov (United States)

    Marhaban, M. H.; Abdullah, A. R.

    2017-01-01

    Manual lifting is one of the common practices used in the industries to transport or move objects to a desired place. Nowadays, even though mechanized equipment is widely available, manual lifting is still considered as an essential way to perform material handling task. Improper lifting strategies may contribute to musculoskeletal disorders (MSDs), where overexertion contributes as the highest factor. To overcome this problem, electromyography (EMG) signal is used to monitor the workers' muscle condition and to find maximum lifting load, lifting height and number of repetitions that the workers are able to handle before experiencing fatigue to avoid overexertion. Past researchers have introduced several EMG processing techniques and different EMG features that represent fatigue indices in time, frequency, and time-frequency domain. The impact of EMG processing based measures in fatigue assessment during manual lifting are reviewed in this paper. It is believed that this paper will greatly benefit researchers who need a bird's eye view of the biosignal processing which are currently available, thus determining the best possible techniques for lifting applications. PMID:28303251

  3. EMG Processing Based Measures of Fatigue Assessment during Manual Lifting

    Directory of Open Access Journals (Sweden)

    E. F. Shair

    2017-01-01

    Full Text Available Manual lifting is one of the common practices used in the industries to transport or move objects to a desired place. Nowadays, even though mechanized equipment is widely available, manual lifting is still considered as an essential way to perform material handling task. Improper lifting strategies may contribute to musculoskeletal disorders (MSDs, where overexertion contributes as the highest factor. To overcome this problem, electromyography (EMG signal is used to monitor the workers’ muscle condition and to find maximum lifting load, lifting height and number of repetitions that the workers are able to handle before experiencing fatigue to avoid overexertion. Past researchers have introduced several EMG processing techniques and different EMG features that represent fatigue indices in time, frequency, and time-frequency domain. The impact of EMG processing based measures in fatigue assessment during manual lifting are reviewed in this paper. It is believed that this paper will greatly benefit researchers who need a bird’s eye view of the biosignal processing which are currently available, thus determining the best possible techniques for lifting applications.

  4. Investigation of Physiological Properties of Nerves and Muscles Using Electromyography

    Science.gov (United States)

    Roe, Seán M.; Johnson, Christopher D.; Tansey, Etain A.

    2014-01-01

    The measurement and representation of the electrical activity of muscles [electromyography (EMG)] have a long history from the Victorian Era until today. Currently, EMG has uses both as a research tool, in noninvasively recording muscle activation, and clinically in the diagnosis and assessment of nerve and muscle disease and injury as well as in…

  5. Influence of fatigue on EMG/force ratio and cocontraction in cycling.

    Science.gov (United States)

    Hautier, C A; Arsac, L M; Deghdegh, K; Souquet, J; Belli, A; Lacour, J R

    2000-04-01

    The purpose of the present study was to observe force and power losses and electromyographic manifestations of fatigue during repeated sprints performed on a friction-loaded cycle ergometer. Ten subjects performed 15 maximal 5-s sprints with 25-s rests between them. Power, velocity, and torque were measured during sprints 1 and 13 and during two submaximal constant-velocity (50 rpm) periods of cycling performed before and after the sprints. The EMG signals of five leg muscles were stored to determine the EMG/force ratio of power producer muscles and the coactivation of antagonist muscles. The power producer muscles were activated to the same level during sprints 1 and 13, despite a loss of force, whereas the vastus lateralis muscle was recruited more during the submaximal cycling period under fatigue conditions. This led to an increased EMG/force ratio for the power producer muscles, indicating the peripheral fatigue status of these muscles. Antagonist muscles were less activated during the sprints after fatigue; whereas they stayed unchanged during the last submaximal cycling period. This suggests that there is a decrease in coactivation as agonist force is lost. This decrease in coactivation under fatigue conditions has not been previously reported and is probably due to the training status of the subjects. Subjects may have learned to better use their antagonist muscles to efficiently transfer force and power to the rotating pedal. This coordination can be adapted to cope with fatigue of the power producer muscles.

  6. Mastication, EMG activity and occlusal contact area in subjects with different facial types.

    Science.gov (United States)

    Gomes, Simone Guimarães Farias; Custodio, William; Jufer, Juliana Silva Moura; Del Bel, Cury Altair Antoninha; Garcia, Renata Cunha Matheus Rodrigues

    2010-10-01

    Dentofacial morphology may affect orofacial functions, therefore the aim of the current study was to evaluate the influence of craniofacial morphology on masticatory function, occlusal contact area (OCA), and masticatory muscles activity. Seventy-eight (78) subjects were divided into three groups according to vertical facial pattern: 1. mesofacial; 2. brachyfacial; and 3. dolichofacial. Artificial material and the sieving method were used to access masticatory efficiency (ME). OCA was determined by registration of posterior teeth. Electromyographic (EMG) activity of the masseter and anterior temporal (AT) muscles was accessed bilaterally at rest and at maximal vertical clenching (MVC). ME (%) was significantly higher in brachyfacial and lower in dolichofacial subjects. Brachyfacials presented the highest OCA (mm2) followed by meso and dolichofacial subjects. The EMG of the masseter and AT at rest and at MVC showed that dolichofacial subjects presented the lowest activity values, while brachyfacial subjects presented significantly higher measurements. Craniofacial morphology affected masticatory function, OCA, and EMG activity of the masticatory muscles.

  7. Features extraction of EMG signal using time domain analysis for arm rehabilitation device

    Science.gov (United States)

    Jali, Mohd Hafiz; Ibrahim, Iffah Masturah; Sulaima, Mohamad Fani; Bukhari, W. M.; Izzuddin, Tarmizi Ahmad; Nasir, Mohamad Na'im

    2015-05-01

    Rehabilitation device is used as an exoskeleton for people who had failure of their limb. Arm rehabilitation device may help the rehab program whom suffers from arm disability. The device that is used to facilitate the tasks of the program should improve the electrical activity in the motor unit and minimize the mental effort of the user. Electromyography (EMG) is the techniques to analyze the presence of electrical activity in musculoskeletal systems. The electrical activity in muscles of disable person is failed to contract the muscle for movements. In order to prevent the muscles from paralysis becomes spasticity, the force of movements should minimize the mental efforts. Therefore, the rehabilitation device should analyze the surface EMG signal of normal people that can be implemented to the device. The signal is collected according to procedure of surface electromyography for non-invasive assessment of muscles (SENIAM). The EMG signal is implemented to set the movements' pattern of the arm rehabilitation device. The filtered EMG signal was extracted for features of Standard Deviation (STD), Mean Absolute Value (MAV) and Root Mean Square (RMS) in time-domain. The extraction of EMG data is important to have the reduced vector in the signal features with less of error. In order to determine the best features for any movements, several trials of extraction methods are used by determining the features with less of errors. The accurate features can be use for future works of rehabilitation control in real-time.

  8. Intraoperative EMG response of the musculature after stimulation of the glenohumeral joint capsule.

    Science.gov (United States)

    Jerosch, J; Steinbeck, J; Schröder, M; Westhues, M; Reer, R

    1997-03-01

    In an experimental study we investigated the EMG response in 10 human subjects after intraarticular stimulation of the shoulder joint capsule following arthroscopic insertion of the stimulating electrode in the anterior glenohumeral ligaments. The muscle response was documented by mono- or bipolar electrodes. Reproducible EMG response patterns were present in superficial as well as in deep muscle layers. The response time ranged from 100 to 516 msec. The earliest muscle response was found in the anterior part of the deltoid muscle and the latest one in the supraspinatus muscle and the lateral part of the deltoid muscle. The results of this study suggest a significant influence of the tension in the joint capsule on the activity of the stabilizing musculature.

  9. Importance of mind-muscle connection during progressive resistance training

    DEFF Research Database (Denmark)

    Calatayud, Joaquin; Vinstrup, Jonas; Jakobsen, Markus Due

    2016-01-01

    PURPOSE: This study evaluates whether focusing on using specific muscles during bench press can selectively activate these muscles. METHODS: Altogether 18 resistance-trained men participated. Subjects were familiarized with the procedure and performed one-maximum repetition (1RM) test during...... electromyography (EMG) signals were recorded for the triceps brachii and pectoralis major muscles. Subsequently, peak EMG of the filtered signals were normalized to maximum maximorum EMG of each muscle. RESULTS: In both muscles, focusing on using the respective muscles increased muscle activity at relative loads...... on activating the triceps muscle the activity of the pectoralis muscle did not decrease. On the contrary, focusing on using the triceps muscle also increased pectoralis EMG at 50 and 60 % of 1RM. CONCLUSION: Resistance-trained individuals can increase triceps brachii or pectarilis major muscle activity during...

  10. EMG Feature Assessment for Myoelectric Pattern Recognition and Channel Selection: A Study with Incomplete Spinal Cord Injury

    Science.gov (United States)

    Liu, Jie; Li, Xiaoyan; Li, Guanglin; Zhou, Ping

    2014-01-01

    Myoelectric pattern recognition with a large number of electromyogram (EMG) channels provides an approach to assessing motor control information available from the recorded muscles. In order to develop a practical myoelectric control system, a feature dependent channel reduction method was developed in this study to determine a small number of EMG channels for myoelectric pattern recognition analysis. The method selects appropriate raw EMG features for classification of different movements, using the minimum Redundancy Maximum Relevance (mRMR) and the Markov random field (MRF) methods to rank a large number of EMG features, respectively. A k-nearest neighbor (KNN) classifier was used to evaluate the performance of the selected features in terms of classification accuracy. The method was tested using 57 channels’ surface EMG signals recorded from forearm and hand muscles of individuals with incomplete spinal cord injury (SCI). Our results demonstrate that appropriate selection of a small number of raw EMG features from different recording channels resulted in similar high classification accuracies as achieved by using all the EMG channels or features. Compared with the conventional sequential forward selection (SFS) method, the feature dependent method does not require repeated classifier implementation. It can effectively reduce redundant information not only cross different channels, but also cross different features in the same channel. Such hybrid feature-channel selection from a large number of EMG recording channels can reduce computational cost for implementation of a myoelectric pattern recognition based control system. PMID:24844608

  11. EMG feature assessment for myoelectric pattern recognition and channel selection: a study with incomplete spinal cord injury.

    Science.gov (United States)

    Liu, Jie; Li, Xiaoyan; Li, Guanglin; Zhou, Ping

    2014-07-01

    Myoelectric pattern recognition with a large number of electromyogram (EMG) channels provides an approach to assessing motor control information available from the recorded muscles. In order to develop a practical myoelectric control system, a feature dependent channel reduction method was developed in this study to determine a small number of EMG channels for myoelectric pattern recognition analysis. The method selects appropriate raw EMG features for classification of different movements, using the minimum Redundancy Maximum Relevance (mRMR) and the Markov random field (MRF) methods to rank a large number of EMG features, respectively. A k-nearest neighbor (KNN) classifier was used to evaluate the performance of the selected features in terms of classification accuracy. The method was tested using 57 channels' surface EMG signals recorded from forearm and hand muscles of individuals with incomplete spinal cord injury (SCI). Our results demonstrate that appropriate selection of a small number of raw EMG features from different recording channels resulted in similar high classification accuracies as achieved by using all the EMG channels or features. Compared with the conventional sequential forward selection (SFS) method, the feature dependent method does not require repeated classifier implementation. It can effectively reduce redundant information not only cross different channels, but also cross different features in the same channel. Such hybrid feature-channel selection from a large number of EMG recording channels can reduce computational cost for implementation of a myoelectric pattern recognition based control system. Copyright © 2014 IPEM. Published by Elsevier Ltd. All rights reserved.

  12. The EEG Correlates of the TMS Induced EMG Silent Period in Humans

    Science.gov (United States)

    Farzan, Faranak; Barr, Mera S.; Hoppenbrouwers, Sylco S.; Fitzgerald, Paul B.; Chen, Robert; Pascual-Leone, Alvaro; Daskalakis, Zafiris J.

    2014-01-01

    Application of magnetic or electrical stimulation to the motor cortex can result in a period of electromyography (EMG) silence in a tonically active peripheral muscle. This period of EMG silence is referred to as the silent period (SP). The duration of SP shows intersubject variability and reflects the integrity of cortical and corticospinal pathways. A non-invasive technique for assessing the duration of SP is the combination of Transcranial Magnetic Stimulation (TMS) with EMG. Utilizing TMS-EMG, several studies have reported on the shortening or lengthening of SP in neuropsychiatric disorders such as schizophrenia, bipolar disorder, depression, obsessive compulsive disorder, epilepsy, Parkinson’s disease, and stroke. However, cortical, corticospinal and peripheral components are difficult to disentangle from EMG alone. Here, we use the multimodal neuroimaging technique of TMS-EMG combined with concurrent electroencephalography (EEG) recording to further examine the cortical origin of SP and the cortical oscillatory activity that underlies SP genesis. We demonstrate that the duration of SP is related to the temporal characteristics of the cortical reactivity and the power of delta to alpha oscillations in both local and remote areas ipsilateral and contralateral to the stimulation site, and beta oscillations locally. We illustrate that, compared to EMG, the EEG indices of the SP provide additional information about the brain dynamics and propose that the EEG measures of SP may be used in future clinical and research investigations to more precisely delineate the mechanisms underlying inhibitory impairments. PMID:23800790

  13. The EEG correlates of the TMS-induced EMG silent period in humans.

    Science.gov (United States)

    Farzan, Faranak; Barr, Mera S; Hoppenbrouwers, Sylco S; Fitzgerald, Paul B; Chen, Robert; Pascual-Leone, Alvaro; Daskalakis, Zafiris J

    2013-12-01

    Application of magnetic or electrical stimulation to the motor cortex can result in a period of electromyography (EMG) silence in a tonically active peripheral muscle. This period of EMG silence is referred to as the silent period (SP). The duration of SP shows intersubject variability and reflects the integrity of cortical and corticospinal pathways. A non-invasive technique for assessing the duration of SP is the combination of Transcranial Magnetic Stimulation (TMS) with EMG. Utilizing TMS-EMG, several studies have reported on the shortening or lengthening of SP in neuropsychiatric disorders such as schizophrenia, bipolar disorder, depression, obsessive compulsive disorder, epilepsy, Parkinson's disease, and stroke. However, cortical, corticospinal and peripheral components are difficult to disentangle from EMG alone. Here, we use the multimodal neuroimaging technique of TMS-EMG combined with concurrent electroencephalography (EEG) recording to further examine the cortical origin of SP and the cortical oscillatory activity that underlies SP genesis. We demonstrate that the duration of SP is related to the temporal characteristics of the cortical reactivity and the power of delta to alpha oscillations in both local and remote areas ipsilateral and contralateral to the stimulation site, and beta oscillations locally. We illustrate that, compared to EMG, the EEG indices of the SP provide additional information about the brain dynamics and propose that the EEG measures of SP may be used in future clinical and research investigations to more precisely delineate the mechanisms underlying inhibitory impairments. Copyright © 2013 Elsevier Inc. All rights reserved.

  14. Intensity-dependent EMG response for the biceps brachii during sustained maximal and submaximal isometric contractions.

    Science.gov (United States)

    Carr, Joshua C; Beck, Travis W; Ye, Xin; Wages, Nathan P

    2016-09-01

    There have been recent attempts to characterize the mechanisms associated with fatigue-induced task failure. We compared the time to failure and the corresponding changes in the surface electromyogram (EMG) during sustained maximal and submaximal isometric force tasks. EMG activity was measured from the biceps brachii of 18 male participants as they sustained either a maximal or submaximal (60 % MVC) isometric contraction of the dominant elbow flexors until force could not be maintained above 55 % MVC. Intensity-dependent patterns of change were observed for EMG amplitude and mean power frequency (MNF) between the two force tasks. Interestingly, the only significant predictor of failure time was the rate of change in EMG MNF during the submaximal task (r (2) = 0.304). In addition, EMG amplitude at submaximal failure was significantly lower (p EMG response emphasize the basis of neuromuscular fatigue and task dependency. Additionally, our data suggest that the EMG MNF should be used when monitoring the progression of local muscle fatigue.

  15. FastICA peel-off for ECG interference removal from surface EMG.

    Science.gov (United States)

    Chen, Maoqi; Zhang, Xu; Chen, Xiang; Zhu, Mingxing; Li, Guanglin; Zhou, Ping

    2016-06-13

    Multi-channel recording of surface electromyographyic (EMG) signals is very likely to be contaminated by electrocardiographic (ECG) interference, specifically when the surface electrode is placed on muscles close to the heart. A novel fast independent component analysis (FastICA) based peel-off method is presented to remove ECG interference contaminating multi-channel surface EMG signals. Although demonstrating spatial variability in waveform shape, the ECG interference in different channels shares the same firing instants. Utilizing the firing information estimated from FastICA, ECG interference can be separated from surface EMG by a "peel off" processing. The performance of the method was quantified with synthetic signals by combining a series of experimentally recorded "clean" surface EMG and "pure" ECG interference. It was demonstrated that the new method can remove ECG interference efficiently with little distortion to surface EMG amplitude and frequency. The proposed method was also validated using experimental surface EMG signals contaminated by ECG interference. The proposed FastICA peel-off method can be used as a new and practical solution to eliminating ECG interference from multichannel EMG recordings.

  16. Normalizing shoulder EMG: An optimal set of maximum isometric voluntary contraction tests considering reproducibility.

    Science.gov (United States)

    Schwartz, Cédric; Tubez, François; Wang, François-Charles; Croisier, Jean-Louis; Brüls, Olivier; Denoël, Vincent; Forthomme, Bénédicte

    2017-08-18

    Normalization of the electromyography (EMG) signal is often performed relatively to maximal voluntary activations (MVA) obtained during maximum isometric voluntary contraction (MVIC). The first aim was to provide an inter-session reproducible protocol to normalize the signal of eight shoulder muscles. The protocol should also lead to a level of activation >90% of MVA for >90% of the volunteers. The second aim was to evaluate the influence of the method used to extract the MVA from the EMG envelope on the normalized EMG signal. Thirteen volunteers performed 12 MVICs twice (one week interval). Several time constants (100ms to 2s) were compared when extracting the MVA from the EMG envelope. The EMG activity was also acquired during an arm elevation. Our results show that a combination of nine MVIC tests was required to meet our requirements including reproducibility. Both the number of MVIC tests and the size of the time constant influence the normalized EMG signal during the dynamic activity (variations up to 15%). A time constant of 1s was a good compromise to extract the MVA. These findings are valuable to improve the reproducibility of EMG signal normalization. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Automatic segmentation of surface EMG images: Improving the estimation of neuromuscular activity.

    Science.gov (United States)

    Vieira, Taian M M; Merletti, Roberto; Mesin, Luca

    2010-08-10

    Surface electromyograms (EMGs) recorded with a couple of electrodes are meant to comprise representative information of the whole muscle activation. Nonetheless, regional variations in neuromuscular activity seem to occur in numerous conditions, from standing to passive muscle stretching. In this study, we show how local activation of skeletal muscles can be automatically tracked from EMGs acquired with a bi-dimensional grid of surface electrodes (a grid of 8 rows and 15 columns was used). Grayscale images were created from simulated and experimental EMGs, filtered and segmented into clusters of activity with the watershed algorithm. The number of electrodes on each cluster and the mean level of neuromuscular activity were used to assess the accuracy of the segmentation of simulated signals. Regardless of the noise level, thickness of fat tissue and acquisition configuration (monopolar or single differential), the segmentation accuracy was above 60%. Accuracy values peaked close to 95% when pixels with intensity below approximately 70% of maximal EMG amplitude in each segmented cluster were excluded. When simulating opposite variations in the activity of two adjacent muscles, watershed segmentation produced clusters of activity consistently centered on each simulated portion of active muscle and with mean amplitude close to the simulated value. Finally, the segmentation algorithm was used to track spatial variations in the activity, within and between medial and lateral gastrocnemius muscles, during isometric plantar flexion contraction and in quiet standing position. In both cases, the regionalization of neuromuscular activity occurred and was consistently identified with the segmentation method. Copyright 2010 Elsevier Ltd. All rights reserved.

  18. Intra-session and inter-day reliability of forearm surface EMG during varying hand grip forces.

    Science.gov (United States)

    Hashemi Oskouei, Alireza; Paulin, Michael G; Carman, Allan B

    2013-02-01

    Surface electromyography (EMG) is widely used to evaluate forearm muscle function and predict hand grip forces; however, there is a lack of literature on its intra-session and inter-day reliability. The aim of this study was to determine reliability of surface EMG of finger and wrist flexor muscles across varying grip forces. Surface EMG was measured from six forearm flexor muscles of 23 healthy adults. Eleven of these subjects undertook inter-day test-retest. Six repetitions of five randomized isometric grip forces between 0% and 80% of maximum force (MVC) were recorded and normalized to MVC. Intra- and inter-day reliability were calculated through the intraclass correlation coefficient (ICC) and standard error of measurement (SEM). Normalized EMG produced excellent intra-session ICC of 0.90 when repeated measurements were averaged. Intra-session SEM was low at low grip forces, however, corresponding normalized SEM was high (23-45%) due to the small magnitude of EMG signals. This may limit the ability to evaluate finer forearm muscle function and hand grip forces in daily tasks. Combining EMG of functionally related muscles improved intra-session SEM, improving within-subject reliability without taking multiple measurements. Removing and replacing electrodes inter-day produced poor ICC (ICC < 0.50) but did not substantially affect SEM. Copyright © 2012 Elsevier Ltd. All rights reserved.

  19. Recognition and prediction of individual and combined muscular activation modes via surface EMG analysis

    Directory of Open Access Journals (Sweden)

    Daniel Graupe

    2010-09-01

    Full Text Available The paper discusses how recognition of individual and combined muscular activation modes (functions and the prediction of intended such modes can be accomplished by identifying parameters of noninvasive surface EMG signals. It outlines the mathematical analysis of surface EMG signal to facilitate such recognition and related prediction, including recognition of intention (in terms of attempts to activate motor functions from the EMG, without accessing the CNS itself, in cases where a patient, say, a high-level amputee does not have the final-activation muscles and joints. The EMG activity thus allows to interpret and recognize CNS commands from minute variations in the parameters of surface EMG signals that record changes in the firing of motor neurons triggering contractions in related muscle fibers. We note that although in popular media this is sometimes referred to as detection of “thoughts”, no thoughts are detected, but only motor-outcomes of thoughts as found in the EMG signal. Examples of concrete cases where such recognition or prediction were accomplished in the author’s lab and in devices that came out of that lab, are given as are references to these in the literature over the last 35 years.

  20. Biofeedback effectiveness to reduce upper limb muscle activity during computer work is muscle specific and time pressure dependent

    DEFF Research Database (Denmark)

    Vedsted, Pernille; Søgaard, Karen; Blangsted, Anne Katrine

    2011-01-01

    Continuous electromyographic (EMG) activity level is considered a risk factor in developing muscle disorders. EMG biofeedback is known to be useful in reducing EMG activity in working muscles during computer work. The purpose was to test the following hypotheses: (1) unilateral biofeedback from...... computer work during two different working conditions (time constraint/no time constraint) while receiving biofeedback. Biofeedback was given from right TRA or EDC through two modes (visual/auditory) by the use of EMG or mechanomyography as biofeedback source. During control sessions (no biofeedback), EMG...

  1. NEUROFEEDBACK AND EMG TRAINING COMBINING EFFICIENCY STUDY IN 6–9 YEARS OLD ADHD CHILDREN

    Directory of Open Access Journals (Sweden)

    Ye. А. Sapina

    2013-01-01

    Full Text Available The research goal was to study neurofeedback and EMG combining training efficiency in ADHD children.To achieve the goal three groups were compared before and after training and six months later. Experimental group included ADHD children 6–9 years old. It was divided into two: group A trained thetabeta ratio and muscle tension decrease simultaneously while group B trained only theta-beta ratio decrease. Control group included healthy children. The results showed significant effect of combined EEG and EMG training for self-control improvement, anxiety and muscle tension decrease in comparison with standard EEG training.

  2. Origin of the low-level EMG during the silent period following transcranial magnetic stimulation

    DEFF Research Database (Denmark)

    Butler, Jane E; Petersen, Nicolas C; Herbert, Robert D

    2012-01-01

    OBJECTIVE: The cortical silent period refers to a period of near silence in the electromyogram (EMG) after transcranial magnetic stimulation (TMS) of the motor cortex during contraction. However, low-level EMG of unknown origin is often present. We hypothesised that it arises through spinal...... reflexes. Sudden lengthening of the muscle as force drops during the silent period could excite muscle spindles and facilitate motoneurones. METHODS: Subjects (n=8) performed maximal isometric, shortening and lengthening contractions of the elbow flexors during which TMS (90-100% output) was delivered over...

  3. Evaluation of pelvic floor muscle strength using four different techniques.

    Science.gov (United States)

    Peschers, U M; Gingelmaier, A; Jundt, K; Leib, B; Dimpfl, T

    2001-01-01

    The aim of the study was to evaluate whether four different techniques were able to correctly measure pelvic floor muscle strength only. Sixteen volunteers performed a set of muscle contractions using the pelvic floor muscles (PFM) only, the abdominal muscles with and without PFM, gluteal muscles with and without PFM, adductor muscles with and without PFM and Valsalva maneuver with and without PFM. Pelvic floor muscle strength was evaluated by digital palpation, intravaginal EMG, pressure perineometry and perineal ultrasound. A 'non-pelvic muscle induced' reading was defined as a significant increase even though the pelvic floor muscles were not contracted. Results were as follows: isolated abdominal muscle contraction: non-pelvic muscle induced readings in 3/8 women with EMG and in 3/8 with pressure perineometry; isolated gluteal muscle contraction: non-pelvic muscle induced readings in 1/2 women with EMG perineometry; isolated adductor muscle contraction: non-pelvic muscle induced readings in 6/11 women with EMG perineometry and in 2/11 women with pressure perineometry; Valsalva maneuver: non-pelvic muscle induced readings in 4/9 women with EMG perineometry and 9/9 women with pressure perineometry. It was concluded that EMG and pressure perineometry do not selectively depict pelvic floor muscle activity.

  4. A study on the effect of age, gender and paralysis on sEMG signals

    CERN Document Server

    Jha, Abhishek

    2015-01-01

    Surface Electromyography (sEMG) is a technology to measure the bio-potentials across the muscles. The true prospective of this technology is yet to be explored. In this paper, a simple and economic construction of a sEMG sensor is proposed. These sensors are used to determine the differences in the Electromyography (EMG) signal patterns of different individuals. Signals of several volunteers from different age groups, gender and individual having paralysis have been obtained. The sEMG data acquisition is done using the soundcard of a computer, hence reducing the need of additional hardware. Finally, the data is used to analyse the relationship between electromyography and factors like age, gender and health condition i.e. paralysis.

  5. Portable EMG devices, Biofeedback and Contingent Electrical Stimulation applications in Bruxism

    DEFF Research Database (Denmark)

    Castrillon, Eduardo

    Portable EMG devices, Biofeedback and Contingent Electrical Stimulation applications in Bruxism Eduardo Enrique, Castrillon Watanabe, DDS, MSc, PhD Section of Orofacial Pain and Jaw Function, Department of Dentistry, Aarhus University, Aarhus, Denmark; Scandinavian Center for Orofacial Neuroscience...... Summary: Bruxism is a parafunctional activity, which involves the masticatory muscles and probably it is as old as human mankind. Different methods such as portable EMG devices have been proposed to diagnose and understand the pathophysiology of bruxism. Biofeedback / contingent electrical stimulation...... (CES) methods have been also studied lately in the field of bruxism as a management method. Results from studies on portable EMG devices that can assess EMG activity on multiple nights, tell us that it is possible to improve the accuracy of the clinical diagnosis of sleep bruxism. New algorithms...

  6. An implementation of movement classification for prosthesis control using custom-made EMG system

    Directory of Open Access Journals (Sweden)

    Mejić Luka

    2017-01-01

    Full Text Available Electromyography (EMG is a well known technique used for recording electrical activity produced by human muscles. In the last few decades, EMG signals are used as a control input for prosthetic hands. There are several multifunctional myoelectric prosthetic hands for amputees on the market, but so forth, none of these devices permits the natural control of more than two degrees of freedom. In this paper we present our implementation of the pattern classification using custom made components (electrodes and an embedded EMG amplifier. The components were evaluated in offline and online tests, in able bodied as well as amputee subjects. This type of control is based on computing the time domain features of the EMG signals recorded from the forearm and using these features as input for a Linear Discriminant Analysis (LDA classifier estimating the intention of the prosthetic user. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. III - 41007

  7. Sex differences in surface EMG interference pattern power spectrum.

    Science.gov (United States)

    Cioni, R; Giannini, F; Paradiso, C; Battistini, N; Navona, C; Starita, A

    1994-11-01

    Sex differences in the spectral parameters of the surface electromyogram (EMG) power spectrum were studied during voluntary muscle contractions of different strength with rest in between. The influence of two different types of leads (unipolar and bipolar) on the values of the spectral parameters was also investigated under the same experimental conditions. The subjects were 15 healthy female and 15 healthy male volunteers. The relationship between the amplitude (root mean square) of the EMG and the force developed was not linear. The mean values of the median power frequency were lower in women than in men. With both types of lead, the increase in force was accompanied by a progressive increase in median power frequency in male and female subjects. The significant differences in spectral parameters observed in the two sexes are probably correlated with anatomic differences.

  8. Locomotor adaptation to a soleus EMG-controlled antagonistic exoskeleton.

    Science.gov (United States)

    Gordon, Keith E; Kinnaird, Catherine R; Ferris, Daniel P

    2013-04-01

    Locomotor adaptation in humans is not well understood. To provide insight into the neural reorganization that occurs following a significant disruption to one's learned neuromuscular map relating a given motor command to its resulting muscular action, we tied the mechanical action of a robotic exoskeleton to the electromyography (EMG) profile of the soleus muscle during walking. The powered exoskeleton produced an ankle dorsiflexion torque proportional to soleus muscle recruitment thus limiting the soleus' plantar flexion torque capability. We hypothesized that neurologically intact subjects would alter muscle activation patterns in response to the antagonistic exoskeleton by decreasing soleus recruitment. Subjects practiced walking with the exoskeleton for two 30-min sessions. The initial response to the perturbation was to "fight" the resistive exoskeleton by increasing soleus activation. By the end of training, subjects had significantly reduced soleus recruitment resulting in a gait pattern with almost no ankle push-off. In addition, there was a trend for subjects to reduce gastrocnemius recruitment in proportion to the soleus even though only the soleus EMG was used to control the exoskeleton. The results from this study demonstrate the ability of the nervous system to recalibrate locomotor output in response to substantial changes in the mechanical output of the soleus muscle and associated sensory feedback. This study provides further evidence that the human locomotor system of intact individuals is highly flexible and able to adapt to achieve effective locomotion in response to a broad range of neuromuscular perturbations.

  9. EMG-based pattern recognition approach in post stroke robot-aided rehabilitation: a feasibility study.

    Science.gov (United States)

    Cesqui, Benedetta; Tropea, Peppino; Micera, Silvestro; Krebs, Hermano Igo

    2013-07-15

    Several studies investigating the use of electromyographic (EMG) signals in robot-based stroke neuro-rehabilitation to enhance functional recovery. Here we explored whether a classical EMG-based patterns recognition approach could be employed to predict patients' intentions while attempting to generate goal-directed movements in the horizontal plane. Nine right-handed healthy subjects and seven right-handed stroke survivors performed reaching movements in the horizontal plane. EMG signals were recorded and used to identify the intended motion direction of the subjects. To this aim, a standard pattern recognition algorithm (i.e., Support Vector Machine, SVM) was used. Different tests were carried out to understand the role of the inter- and intra-subjects' variability in affecting classifier accuracy. Abnormal muscular spatial patterns generating misclassification were evaluated by means of an assessment index calculated from the results achieved with the PCA, i.e., the so-called Coefficient of Expressiveness (CoE). Processing the EMG signals of the healthy subjects, in most of the cases we were able to build a static functional map of the EMG activation patterns for point-to-point reaching movements on the horizontal plane. On the contrary, when processing the EMG signals of the pathological subjects a good classification was not possible. In particular, patients' aimed movement direction was not predictable with sufficient accuracy either when using the general map extracted from data of normal subjects and when tuning the classifier on the EMG signals recorded from each patient. The experimental findings herein reported show that the use of EMG patterns recognition approach might not be practical to decode movement intention in subjects with neurological injury such as stroke. Rather than estimate motion from EMGs, future scenarios should encourage the utilization of these signals to detect and interpret the normal and abnormal muscle patterns and provide

  10. Simultaneous Recording and Analysis of Uterine and Abdominal Muscle Electromyographic Activity in Nulliparous Women During Labor.

    Science.gov (United States)

    Qian, Xueya; Li, Pin; Shi, Shao-Qing; Garfield, Robert E; Liu, Huishu

    2017-03-01

    To record and characterize electromyography (EMG) from the uterus and abdominal muscles during the nonlabor to first and second stages of labor and to define relationships to contractions. Nulliparous patients without any treatments were used (n = 12 nonlabor stage, 48 during first stage and 33 during second stage). Electromyography of both uterine and abdominal muscles was simultaneously recorded from electrodes placed on patients' abdominal surface using filters to separate uterine and abdominal EMG. Contractions of muscles were also recorded using tocodynamometry. Electromyography was characterized by analysis of various parameters. During the first stage of labor, when abdominal EMG is absent, uterine EMG bursts temporally correspond to contractions. In the second stage, uterine EMG bursts usually occur at same frequency as groups of abdominal bursts and precede abdominal bursts, whereas abdominal EMG bursts correspond to contractions and are accompanied by feelings of "urge to push." Uterine EMG increases progressively from nonlabor to second stage of labor. (1) Uterine EMG activity can be separated from abdominal EMG events by filtering. (2) Uterine EMG gradually evolves from the antepartum stage to the first and second stages of labor. (3) Uterine and abdominal EMG reflect electrical activity of the muscles during labor and are valuable to assess uterine and abdominal muscle events that control labor. (4) During the first stage of labor uterine, EMG is responsible for contractions, and during the second stage, both uterine and abdominal muscle participate in labor.

  11. Activation of respiratory muscles during respiratory muscle training.

    Science.gov (United States)

    Walterspacher, Stephan; Pietsch, Fabian; Walker, David Johannes; Röcker, Kai; Kabitz, Hans-Joachim

    2018-01-01

    It is unknown which respiratory muscles are mainly activated by respiratory muscle training. This study evaluated Inspiratory Pressure Threshold Loading (IPTL), Inspiratory Flow Resistive Loading (IFRL) and Voluntary Isocapnic Hyperpnea (VIH) with regard to electromyographic (EMG) activation of the sternocleidomastoid muscle (SCM), parasternal muscles (PARA) and the diaphragm (DIA) in randomized order. Surface EMG were analyzed at the end of each training session and normalized using the peak EMG recorded during maximum inspiratory maneuvers (Sniff nasal pressure: SnPna, maximal inspiratory mouth occlusion pressure: PImax). 41 healthy participants were included. Maximal activation was achieved for SCM by SnPna; the PImax activated predominantly PARA and DIA. Activations of SCM and PARA were higher in IPTL and VIH than for IFRL (pVIH (pVIH differ in activation of inspiratory respiratory muscles. Whereas all methods mainly stimulate accessory respiratory muscles, diaphragm activation was predominant in IPTL. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. MUAP number estimates in surface EMG: template-matching methods and their performance boundaries.

    Science.gov (United States)

    Zhou, Ping; Rymer, William Z

    2004-07-01

    Estimates of the number of motor unit action potential (MUAP)s appearing in the surface electromyogram (EMG) signal, which offers potentially valuable information about motor unit recruitment and firing rates, are likely to provide a more accurate reflection of the neural command to muscle than are current EMG quantification methods. In this paper, we show that the basic shapes of surface MUAPs recorded from the first dorsal interosseous (FDI) muscle can ideally be represented by a small number of waveforms. On the basis of this, we seek to estimate the number of MUAPs present in standard surface EMG records, using template-matching techniques to identify MUAP occurrences. Our simulation study indicates that the performance of template-matching methods for MUAP number estimation is mainly constrained by the MUAP superposition in the signal, and the maximum number of MUAPs allowed in the signal for a good estimation is determined by the duration of MUAPs. To further explore this from experimental surface EMG signals, we compare the recordings from a selective multiple concentric ring electrode against those derived from a standard differential EMG electrode situated over the same muscle. We conclude that the ring surface electrode only slightly reduces the MUAP duration and the less MUAP superposition rate contained in the signal is mainly achieved by reducing the pick up area of the electrode. Using a template-matching method, although the number of MUAPs can be approximately estimated based on a very selective surface EMG recording at low force levels, the maximum number of MUAPs correctly estimated from the surface EMG is constrained by the MUAP duration.

  13. An EMG-driven model of the upper extremity and estimation of long head biceps force.

    Science.gov (United States)

    Langenderfer, Joseph; LaScalza, Suzanne; Mell, Amy; Carpenter, James E; Kuhn, John E; Hughes, Richard E

    2005-01-01

    An electromyography (EMG) driven model of the upper extremity has been developed that incorporates musculoskeletal geometry of the glenohumeral and elbow joints, estimated relevant physiologic muscle parameters including optimal muscle lengths, and EMG activity. The model is designed to predict forces in muscles spanning the glenohumeral joint resulting from functionally relevant tasks. The model is composed of four sub-models that comprise a mathematical as well as graphical three-dimensional representation of the upper extremity: a musculoskeletal model for estimation of muscle-tendon lengths and moment arms, a Hill-based muscle force model, a model for estimating optimal muscle lengths, and a model for estimation of muscle activation from EMG signal of the biceps. The purpose of this paper is to describe the components of the model, as well as the data required to drive the model. Collection of data is described in the context of applying the model to determine biceps muscle forces for testing of functional tasks. Results obtained from applying the model to analyze the functional tasks are summarized, and model strengths and limitations are discussed.

  14. Heterogeneity of muscle activity during sedentary behavior.

    Science.gov (United States)

    Pesola, Arto J; Laukkanen, Arto; Tikkanen, Olli; Finni, Taija

    2016-11-01

    Replacing sitting by standing has been hypothesized to reduce the health risks of sitting, based on the assumption that muscles are passive during sitting and active during standing. Interventions have been more effective in overweight (OW) than in normal weight (NW) individuals, but subjects' muscle activities have not been quantified. This study compared quadriceps and hamstring muscle electromyographic (EMG) activity between 57 NW (body mass index (BMI) 22.5 ± 1.5 kg/m 2 , female n = 36) and 27 OW (BMI 28.4 ± 2.9 kg/m 2 , female n = 8) subjects during non-fatiguing standing (15 s, EMG standing ) and sitting (30 min). EMG amplitude was normalized to EMG measured during maximal isometric knee extension and flexion (% EMG MVC ), and sitting muscle inactivity and bursts were determined using 4 thresholds (60% or 90% EMG standing and 1% or 2% EMG MVC ). Comparisons were adjusted for sex, age, knee extension strength, and the individual threshold. Standing EMG amplitude was 36% higher in OW (1.9% ± 1.5% EMG MVC ) than in NW (1.4% ± 1.4% EMG MVC , P muscles were inactive 89.8% ± 12.7% of the measurement time with 12.7 ± 14.2 bursts/min across all thresholds. On average, 6% more activity was recorded in NW than in OW individuals for 3 of the 4 thresholds (P muscle activity amplitude during standing but more muscle inactivity during sitting for 3/4 of the thresholds tested. Interventions should test whether the observed heterogeneity in muscle activity affects the potential to gain cardiometabolic benefits from replacing sitting with standing.

  15. Generating Control Commands From Gestures Sensed by EMG

    Science.gov (United States)

    Wheeler, Kevin R.; Jorgensen, Charles

    2006-01-01

    of electrodes needed to acquire sufficient data; refinements in the acquisition, filtering, and digitization of EMG signals; and methods of training the pattern- recognition software. The joystick and keyboard simulations were chosen for the initial experiments because they are familiar to many computer users. It is anticipated that, ultimately, interfaces would utilize EMG signals associated with movements more nearly natural than those associated with joysticks or keyboards. Future versions of the pattern-recognition software are planned to be capable of adapting to the preferences and day-today variations in EMG outputs of individual users; this capability for adaptation would also make it possible to select gestures that, to a given user, feel the most nearly natural for generating control signals for a given task (provided that there are enough properly positioned electrodes to acquire the EMG signals from the muscles involved in the gestures).

  16. Augmented effects of EMG biofeedback interfaced with virtual reality on neuromuscular control and movement coordination during reaching in children with cerebral palsy.

    Science.gov (United States)

    Yoo, Ji Won; Lee, Dong Ryul; Cha, Young Joo; You, Sung Hyun

    2017-01-01

    The purpose of the present study was to compare therapeutic effects of an electromyography (EMG) biofeedback augmented by virtual reality (VR) and EMG biofeedback alone on the triceps and biceps (T:B) muscle activity imbalance and elbow joint movement coordination during a reaching motor taskOBJECTIVE: To compare therapeutic effects of an electromyography (EMG) biofeedback augmented by virtual reality (VR) and EMG biofeedback alone on the triceps and biceps muscle activity imbalance and elbow joint movement coordination during a reaching motor task in normal children and children with spastic cerebral palsy (CP). 18 children with spastic CP (2 females; mean±standard deviation = 9.5 ± 1.96 years) and 8 normal children (3 females; mean ± standard deviation = 9.75 ± 2.55 years) were recruited from a local community center. All children with CP first underwent one intensive session of EMG feedback (30 minutes), followed by one session of the EMG-VR feedback (30 minutes) after a 1-week washout period. Clinical tests included elbow extension range of motion (ROM), biceps muscle strength, and box and block test. EMG triceps and biceps (T:B) muscle activity imbalance and reaching movement acceleration coordination were concurrently determined by EMG and 3-axis accelerometer measurements respectively. Independent t-test and one-way repeated analysis of variance (ANOVA) were performed at p EMG biofeedback when augmented by virtual reality exercise games in children with spastic CP. The augmented EMG and VR feedback produced better neuromuscular balance control in the elbow joint than the EMG biofeedback alone.

  17. Can muscle coordination be precisely studied by surface electromyography?

    Science.gov (United States)

    Hug, François

    2011-02-01

    Despite the many reviews and research papers on the limitations of surface electromyography (EMG), there are relatively few that address this issue by considering dynamic contractions and specifically from the point of view of muscle coordination. Nevertheless, whether muscle coordination can be precisely studied using surface EMG signals is still a matter of discussion in the scientific community. In other words, it is uncertain whether neural control strategies of movement can be inferred from EMG. This review article discusses the appropriateness of using EMG recordings for studying muscle coordination. First, the main uses of surface EMG for studying muscle coordination are depicted. Then, the main intrinsic drawbacks of the EMG technique (i.e., amplitude cancellation, crosstalk and spatial variability of muscle activity) and of EMG processing (i.e., smoothing of the linear envelope, normalization of the time scale and the amplitude and timing of muscle activation) are described and discussed. Finally, three other factors (i.e., variability, electromechanical delay and neuromuscular fatigue), which can affect the interpretation of EMG and have received little attention in the literature, are presented and discussed. All of this information is crucial to the proper interpretation of muscle coordination from EMG signals. Copyright © 2010 Elsevier Ltd. All rights reserved.

  18. Mudanças no padrão temporal da EMG de músculos do tornozelo e pé pré e pós-aterrissagem em jogadores de voleibol com instabilidade funcional Changes in the EMG temporal pattern of pre and post-landing of ankle and foot muscles in volleyball players with functional instability

    Directory of Open Access Journals (Sweden)

    Eneida Yuri Suda

    2008-08-01

    Full Text Available INTRODUÇÃO: A instabilidade funcional (IF é a complicação mais comum após o entorse de tornozelo; acomete até 52% dos atletas com história de entorse. O entorse de tornozelo é uma das lesões esportivas mais comuns, inclusive no voleibol, em que 90% dos entorses de tornozelo ocorrem durante a aterrissagem, após o movimento de bloqueio. A IF é definida por queixas de falseios e entorses recorrentes, sem que haja evidências clínicas de lesão ligamentar, sendo extremamente prejudicial para a prática do voleibol, pois interfere na realização dos fundamentos envolvidos na modalidade. OBJETIVOS: Comparar os padrões temporais e de magnitude da atividade eletromiográfica dos músculos tibial anterior (TA, fibular longo (FL e gastrocnêmio lateral (GL durante a aterrissagem do salto vertical após a execução da habilidade do bloqueio do voleibol entre jogadores com e sem IF de tornozelo. MÉTODOS: Foi adquirida a atividade EMG do tibial anterior, do fibular longo e do gastrocnêmio lateral em 21 atletas com IF (GI e em 19 atletas controle (GC - idade média de 20 ± 4 anos. Os envoltórios lineares foram calculados para cada um dos grupos no período de tempo entre 200ms antes e 200ms após o instante do impacto, determinados por meio da componente vertical da FRS. A magnitude e o instante do pico máximo de cada um dos músculos também foram determinados matematicamente. Os grupos foram comparados por meio do teste t (α = 0,05. RESULTADOS: O grupo com instabilidade apresentou instante de pico do TA mais tardio ± (GC = -107,4 ± 29,6ms; GI = -134,0 ± 26,0ms e FL (GC = -11,0 ± 55,9ms; GI = -41,7 ± 49,8ms e menor pico de TA (GC = 68,5 ± 17,2%; GI = 81,2 ± 28,8% e FL (GC = 72,9 ± 27,3%; GI = 59,1 ± 16,0%, CONCLUSÕES: Os resultados mostram um padrão de alteração mais tardio e com menor magnitude nos músculos de atletas com IF que podem predispô-los à condição de instabilidade, mesmo na ausência de lesão anat

  19. EMG-biofeedback training in fibromyalgia syndrome.

    Science.gov (United States)

    Ferraccioli, G; Ghirelli, L; Scita, F; Nolli, M; Mozzani, M; Fontana, S; Scorsonelli, M; Tridenti, A; De Risio, C

    1987-08-01

    Fifteen patients with fibromyalgia syndrome were given EMG-BFB (biofeedback) training sessions because of persistent aches after one year of monthly courses of NSAID. A long-lasting clinical benefit was observed in 56%. The improvement was found in those without overt psychopathological disturbances. In fact, a subgroup of clinically depressed patients responded poorly. Our findings were confirmed in a controlled study. Six patients were allocated into "true EMG-BFB" and 6 into "false EMG-BFB" treatment in a blinded fashion. The rheumatological assessment revealed a significant improvement in most of the variables only in the "true EMG-BFB" group.

  20. Quantitative surface electromyography (qEMG): applications in anaesthesiology and critical care.

    Science.gov (United States)

    Paloheimo, M

    1990-01-01

    During general anaesthesia and in lowered vigilance states such as after major trauma and during heavy sedation or analgesic medication, patients' ability to communicate with their surroundings is limited. Subjective intuitional interpretation may be the only means to ascertain a patient's emotional state, mood, and pain perception. Electromyographic detection and quantification of minimal and covert facial mimic muscle activity in anaesthesiology and critical care was an interesting concept worth further evaluation. In this study, the behaviour of quantitative surface-detected electromyographic activity (qEMG) was investigated during common anaesthetic events, post-operatively, and in volunteers as well as in experimental animals. A review of the methodology includes the necessary details for reproduction of the studies, including computerized processing of numerical data available in the commercial equipment. Results from the monitoring of 218 patients, seven volunteers and 31 rats are discussed. Conclusions are based on 32 testable null-hypotheses, the earlier documented literature and the author's own experience. The qEMG signal was derived from two electrodes placed on the frontal area and on the mastoid process behind the ipsilateral ear. After amplification, the signal was filtered to obtain a portion containing electrical activity between 60-300 Hz, which was considered to represent electromyographic activity. The signals were thereafter full-wave rectified and averaged with a 1-s time constant. The output of the processing unit consisted of a graphics display and a numeric computer output. A variety of clinical conditions and drug effects were studied in order to evaluate the method's applicability in research and in routine anaesthetic practice. The facial muscles turned out to be less sensitive to the effects of neuromuscular blocking drugs than the hand muscles, the normal monitoring site of neuromuscular transmission. Although muscle relaxants had a

  1. Electromyographic biofeedback training for reducing muscle pain and tension on masseter and temporal muscles: A pilot study

    Science.gov (United States)

    de La Fuente, Antonio; Heredia, Margarita; Montero, Javier; Albaladejo, Alberto; Criado, José-María

    2016-01-01

    Background Due to the absence of agreement about an effective unified treatment for temporomandibular disorders, non-invasive therapies such as EMG-biofeedback generate a greater interest. Furthermore, most studies to the present show methodological deficiencies that must be solved in the future, which makes important to emphasize this line of studies. Material and Methods Fourteen patients were selected for this case series study, and replied to a questionnaire concerning awareness of bruxism, painful muscles, and muscle tension. They also practiced an intraoral exploration (occlusal analysis and mandibular dynamics), and an extraoral exploration of the head and neck muscles and the temporomandibular joint. Before each session, patients responded to a questionnaire about the subjective perceived improvement. In each session, a period of three minutes of pre-biofeedback EMG activity of right masseter and temporal muscles was registered, then patients performed 30 iterations of visual EMG-biofeedback training and finally, a period of three minutes of post-EMG activity was also registered for those muscles. Patients performed four sessions. Results A decrease in painful symptoms was found for all patients since the first session. EMG activity decreases (p<0,05) in both muscles during the biofeedback training stage, in the four sessions. It is also observed a decrease (p<0,05) in EMG activity in the masseter muscle at the post-biofeedback stage, in the second and third sessions. There is likewise a decrease in EMG post-biofeedback activity of the temporal muscle (p<0,05) in sessions two, three, and four. Conclusions EMG-biofeedback training produces a decrease in EMG activity in both masseter and temporal muscles during the session. This decrease persists during the post-biofeedback period since the second session. Also there is a decrease in painful symptoms for all patients. Key words:Muscle tension, muscle pain, EMG-biofeedback, masseter muscle, temporal muscle

  2. Instrumentation for ENG and EMG recordings in FES systems.

    Science.gov (United States)

    Nikolić, Z M; Popović, D B; Stein, R B; Kenwell, Z

    1994-07-01

    An electronic circuit for analog processing of neural (electroneurogram or ENG) and muscular (electromyogram or EMG) signals in functional electrical stimulation (FES) systems is described in this paper. The basic circuit consists of a low-noise gated preamplifier, band-pass filter, amplifier, and a blanking circuit to minimize stimulation artifacts during electrical stimulation. This device was tested in chronic recordings using a triphasic cuff electrode for nerves and epimysial electrodes for muscles in the hind limbs of cats. The device was used for nerve recordings in the presence of electrical stimulation of muscles in the same leg. The recordings showed rejection of stimulation and muscle (M-wave) artifacts, while retaining the information of interest.

  3. Longitudinal high-density EMG classification: Case study in a glenohumeral TMR subject.

    Science.gov (United States)

    Schweisfurth, Meike A; Ernst, Jennifer; Vujaklija, Ivan; Schilling, Arndt F; Farina, Dario; Aszmann, Oskar C; Felmerer, Gunther

    2017-07-01

    Targeted muscle reinnervation (TMR) represents a breakthrough interface for prosthetic control in high-level upper-limb amputees. However, clinically, it is still limited to the direct motion-wise control restricted by the number of reinnervation sites. Pattern recognition may overcome this limitation. Previous studies on EMG classification in TMR patients experienced with myocontrol have shown greater accuracy when using high-density (HD) recordings compared to conventional single-channel derivations. This case study investigates the potential of HD-EMG classification longitudinally over a period of 17 months post-surgery in a glenohumeral amputee. Five experimental sessions, separated by approximately 3 months, were performed. They were timed during a standard rehabilitation protocol that included intensive physio- and occupational therapy, myosignal training, and routine use of the final myoprosthesis. The EMG signals recorded by HD-EMG grids were classified into 12 classes. The first sign of EMG activity was observed in the second experimental session. The classification accuracy over 12 classes was 76% in the third session and ∼95% in the last two sessions. When using training and testing sets that were acquired with a 1-h time interval in between, a much lower accuracy (32%, Session 4) was obtained, which improved upon prosthesis usage (Session 5, 67%). The results document the improvement in EMG classification accuracy throughout the TMR-rehabilitation process.

  4. Teager–Kaiser energy operator signal conditioning improves EMG onset detection

    Science.gov (United States)

    Rider, Patrick; Steinweg, Ken; DeVita, Paul; Hortobágyi, Tibor

    2010-01-01

    Accurate identification of the onset of muscle activity is an important element in the biomechanical analysis of human movement. The purpose of this study was to determine if inclusion of the Teager–Kaiser energy operator (TKEO) in signal conditioning would increase the accuracy of popular electromyography (EMG) onset detection methods. Three methods, visual determination, threshold-based method, and approximated generalized likelihood ratio were used to estimate the onset of EMG burst with and without TKEO conditioning. Reference signals, with known onset times, were constructed from EMG signals collected during isometric contraction of the vastus lateralis (n = 17). Additionally, vastus lateralis EMG signals (n = 255) recorded during gait were used to evaluate a clinical application of the TKEO conditioning. Inclusion of TKEO in signal conditioning significantly reduced mean detection error of all three methods compared with signal conditioning without TKEO, using artificially generated reference data (13 vs. 98 ms, p EMG signals increases the detection accuracy of EMG burst boundaries. PMID:20526612

  5. Research on Lower Limb Motion Recognition Based on Fusion of sEMG and Accelerometer Signals

    Directory of Open Access Journals (Sweden)

    Qingsong Ai

    2017-08-01

    Full Text Available Since surface electromyograghic (sEMG signals are non-invasive and capable of reflecting humans’ motion intention, they have been widely used for the motion recognition of upper limbs. However, limited research has been conducted for lower limbs, because the sEMGs of lower limbs are easily affected by body gravity and muscle jitter. In this paper, sEMG signals and accelerometer signals are acquired and fused to recognize the motion patterns of lower limbs. A curve fitting method based on median filtering is proposed to remove accelerometer noise. As for movement onset detection, an sEMG power spectral correlation coefficient method is used to detect the start and end points of active signals. Then, the time-domain features and wavelet coefficients of sEMG signals are extracted, and a dynamic time warping (DTW distance is used for feature extraction of acceleration signals. At last, five lower limbs’ motions are classified and recognized by using Gaussian kernel-based linear discriminant analysis (LDA and support vector machine (SVM respectively. The results prove that the fused feature-based classification outperforms the classification with only sEMG signals or accelerometer signals, and the fused feature can achieve 95% or higher recognition accuracy, demonstrating the validity of the proposed method.

  6. Effect of sex on torque, recovery, EMG, and MMG responses to fatigue

    Science.gov (United States)

    Hill, E.C.; Housh, T.J.; Smith, C.M.; Cochrane, K.C.; Jenkins, N.D.M.; Cramer, J.T.; Schmidt, R.J.; Johnson, G.O.

    2016-01-01

    Objective: The purpose of the present investigation was to examine the effect of sex on maximal voluntary isometric contraction (MVIC) torque and the EMG and MMG responses as a result of fatiguing, intermittent, submaximal (65% of MVIC), isometric elbow flexion muscle contractions. Methods: Eighteen men and women performed MVIC trials before (pretest), after (posttest), and 5-min after (5-min recovery) performing 50 intermittent, submaximal isometric muscle contractions. Surface electromyographic (EMG) and mechanomyographic (MMG) signals were simultaneously recorded from the biceps brachii muscle. Results: As a result of the fatiguing workbout torque decreased similarly from pretest to posttest for both the men (24.0%) and women (23.3%). After 5-min of recovery, torque had partially recovered for the men, while torque had returned to pretest levels for the women. For both sexes, from pretest to posttest EMG mean power frequency and MMG amplitude decreased, but returned to pretest levels after 5-min of recovery. Conclusions: In the present study, there were sex-related differences in muscle fatigue that were not associated with the EMG or MMG responses. PMID:27973383

  7. FMRl analysis for motor paradigms using EMG-Based designs : A validation study

    NARCIS (Netherlands)

    Van Rootselaar, Anne-Fleur; Renken, Remco; De Jong, Bauke M.; Hoogduin, Johannes M.; Tijssen, Marina A. J.; Maurits, Natasha M.

    2007-01-01

    The goal of the present validation study is to show that continuous surface EMG recorded simultaneously with 3T fMRI can be used to identify local brain activity related to (1) motor tasks, and to (2) muscle activity independently of a specific motor task, i.e. spontaneous (abnormal) movements. Five

  8. fMRI analysis for motor paradigms using EMG-based designs: a validation study

    NARCIS (Netherlands)

    van Rootselaar, Anne-Fleur; Renken, Remco; de Jong, Bauke M.; Hoogduin, Johannes M.; Tijssen, Marina A. J.; Maurits, Natasha M.

    2007-01-01

    The goal of the present validation study is to show that continuous surface EMG recorded simultaneously with 3T fMRI can be used to identify local brain activity related to (1) motor tasks, and to (2) muscle activity independently of a specific motor task, i.e. spontaneous (abnormal) movements. Five

  9. Suppression of EMG activity by transcranial magnetic stimulation in human subjects during walking

    DEFF Research Database (Denmark)

    Petersen, Nicolas Caesar; Butler, Jane E; Marchand-Pauvert, Veronique

    2001-01-01

    1. The involvement of the motor cortex during human walking was evaluated using transcranial magnetic stimulation (TMS) of the motor cortex at a variety of intensities. Recordings of EMG activity in tibialis anterior (TA) and soleus muscles during walking were rectified and averaged. 2. TMS of lo...

  10. FEATURE EXTRACTION FOR EMG BASED PROSTHESES CONTROL

    Directory of Open Access Journals (Sweden)

    R. Aishwarya

    2013-01-01

    Full Text Available The control of prosthetic limb would be more effective if it is based on Surface Electromyogram (SEMG signals from remnant muscles. The analysis of SEMG signals depend on a number of factors, such as amplitude as well as time- and frequency-domain properties. Time series analysis using Auto Regressive (AR model and Mean frequency which is tolerant to white Gaussian noise are used as feature extraction techniques. EMG Histogram is used as another feature vector that was seen to give more distinct classification. The work was done with SEMG dataset obtained from the NINAPRO DATABASE, a resource for bio robotics community. Eight classes of hand movements hand open, hand close, Wrist extension, Wrist flexion, Pointing index, Ulnar deviation, Thumbs up, Thumb opposite to little finger are taken into consideration and feature vectors are extracted. The feature vectors can be given to an artificial neural network for further classification in controlling the prosthetic arm which is not dealt in this paper.

  11. Coordinated upper limb training assisted with an electromyography (EMG)-driven hand robot after stroke.

    Science.gov (United States)

    Hu, X L; Tong, K Y; Wei, X J; Rong, W; Susanto, E A; Ho, S K

    2013-01-01

    An electromyography (EMG)-driven hand robot had been developed for post-stroke rehabilitation training. The effectiveness of the hand robot assisted whole upper limb training on muscular coordination was investigated on persons with chronic stroke (n=10) in this work. All subjects attended a 20-session training (3-5 times/week) by using the hand robot to practice object grasp/release and arm transportation tasks. Improvements were found in the muscle co-ordination between the antagonist muscle pair (flexor digitorum and extensor digitorum) as measured by muscle co-contractions in EMG signals; and also in the reduction of excessive muscle activities in the biceps brachii. Reduced spasticity in the fingers was also observed as measured by the Modified Ashworth Score.

  12. A switching regime model for the EMG-based control of a robot arm.

    Science.gov (United States)

    Artemiadis, Panagiotis K; Kyriakopoulos, Kostas J

    2011-02-01

    Human-robot control interfaces have received increased attention during the last decades. These interfaces increasingly use signals coming directly from humans since there is a strong necessity for simple and natural control interfaces. In this paper, electromyographic (EMG) signals from the muscles of the human upper limb are used as the control interface between the user and a robot arm. A switching regime model is used to decode the EMG activity of 11 muscles to a continuous representation of arm motion in the 3-D space. The switching regime model is used to overcome the main difficulties of the EMG-based control systems, i.e., the nonlinearity of the relationship between the EMG recordings and the arm motion, as well as the nonstationarity of EMG signals with respect to time. The proposed interface allows the user to control in real time an anthropomorphic robot arm in the 3-D space. The efficiency of the method is assessed through real-time experiments of four persons performing random arm motions.

  13. EMG-Based Continuous and Simultaneous Estimation of Arm Kinematics in Able-Bodied Individuals and Stroke Survivors

    Directory of Open Access Journals (Sweden)

    Jie Liu

    2017-08-01

    Full Text Available Among the potential biological signals for human-machine interactions (brain, nerve, and muscle signals, electromyography (EMG widely used in clinical setting can be obtained non-invasively as motor commands to control movements. The aim of this study was to develop a model for continuous and simultaneous decoding of multi-joint dynamic arm movements based on multi-channel surface EMG signals crossing the joints, leading to application of myoelectrically controlled exoskeleton robots for upper-limb rehabilitation. Twenty subjects were recruited for this study including 10 stroke subjects and 10 able-bodied subjects. The subjects performed free arm reaching movements in the horizontal plane with an exoskeleton robot. The shoulder, elbow and wrist movements and surface EMG signals from six muscles crossing the three joints were recorded. A non-linear autoregressive exogenous (NARX model was developed to continuously decode the shoulder, elbow and wrist movements based solely on the EMG signals. The shoulder, elbow and wrist movements were decoded accurately based only on the EMG inputs in all the subjects, with the variance accounted for (VAF > 98% for all three joints. The proposed approach is capable of simultaneously and continuously decoding multi-joint movements of the human arm by taking into account the non-linear mappings between the muscle EMGs and joint movements, which may provide less effortful control of robotic exoskeletons for rehabilitation training of individuals with neurological disorders and arm impairment.

  14. The impact of shoulder abduction loading on EMG-based intention detection of hand opening and closing after stroke.

    Science.gov (United States)

    Lan, Yiyun; Yao, Jun; Dewald, Julius P A

    2011-01-01

    Many stroke patients are subject to limited hand functions in the paretic arm due to a significant loss of Corticospinal Tract (CST) fibers. A possible solution for this problem is to classify surface Electromyography (EMG) signals generated by hand movements and uses that to implement Functional Electrical Stimulation (FES). However, EMG usually presents an abnormal muscle coactivation pattern shown as increased coupling between muscles within and/or across joints after stroke. The resulting Abnormal Muscle Synergies (AMS) could make the classification more difficult in individuals with stroke, especially when attempting to use the hand together with other joints in the paretic arm. Therefore, this study is aimed at identifying the impact of AMS following stroke on EMG pattern recognition between two hand movements. In an effort to achieve this goal, 7 chronic hemiparetic chronic stroke subjects were recruited and asked to perform hand opening and closing movements at their paretic arm while being either fully supported by a virtual table or loaded with 25% of subject's maximum shoulder abduction force. During the execution of motor tasks EMG signals from the wrist flexors and extensors were simultaneously acquired. Our results showed that increased synergy-induced activity at elbow flexors, induced by increasing shoulder abduction loading, deteriorated the performance of EMG pattern recognition for hand opening for those with a weak grasp strength and EMG activity. However, no such impact on hand closing has yet been observed possibly because finger/wrist flexion is facilitated by the shoulder abduction-induced flexion synergy.

  15. Automatic analysis of EMG during clonus

    Science.gov (United States)

    Mummidisetty, Chaithanya K.; Bohorquez, Jorge; Thomas, Christine K

    2011-01-01

    Clonus can disrupt daily activities after spinal cord injury. Here an algorithm was developed to automatically detect contractions during clonus in 24-hour electromyographic (EMG) records. Filters were created by non-linearly scaling a Mother (Morlet) wavelet to envelope the EMG using different frequency bands. The envelope for the intermediate band followed the EMG best (74.8–193.9 Hz). Threshold and time constraints were used to reduce the envelope peaks to one per contraction. Energy in the EMG was measured 50 ms either side of each envelope (contraction) peak. Energy values at 5 % and 95 % maximal defined EMG start and end time, respectively. The algorithm was as good as a person at identifying contractions during clonus (p = 0.946, n=31 spasms, 7 subjects with cervical spinal cord injury), and marking start and end times to determine clonus frequency (intra class correlation coefficient, α: 0.949), contraction intensity using root mean square EMG (α: 0.997) and EMG duration (α: 0.852). On average the algorithm was 574 times faster than manual analysis performed independently by two people (p≤ 0.001). This algorithm is an important tool for characterization of clonus in long-term EMG records. PMID:22057220

  16. Estudi de la señal de EMG pel tratactament de la incontinència urinària

    OpenAIRE

    Benasques Borau, Laura

    2016-01-01

    This project is focused on the analysis of the Electromyographic signal (EMG) of the pelvic floor muscles during the realization of physical exercises oriented to increase the strength of the muscles. These exercises are oriented to reduce urinary incontinence in adult women. Studying records of electromyography (EMG) under conditions similar to a randomized clinical trial. With the records obtained, it is expected to study where is the best location of the electrodes in the abdomen to det...

  17. Surface EMG pattern recognition for real-time control of a wrist exoskeleton

    Directory of Open Access Journals (Sweden)

    Khokhar Zeeshan O

    2010-08-01

    Full Text Available Abstract Background Surface electromyography (sEMG signals have been used in numerous studies for the classification of hand gestures and movements and successfully implemented in the position control of different prosthetic hands for amputees. sEMG could also potentially be used for controlling wearable devices which could assist persons with reduced muscle mass, such as those suffering from sarcopenia. While using sEMG for position control, estimation of the intended torque of the user could also provide sufficient information for an effective force control of the hand prosthesis or assistive device. This paper presents the use of pattern recognition to estimate the torque applied by a human wrist and its real-time implementation to control a novel two degree of freedom wrist exoskeleton prototype (WEP, which was specifically developed for this work. Methods Both sEMG data from four muscles of the forearm and wrist torque were collected from eight volunteers by using a custom-made testing rig. The features that were extracted from the sEMG signals included root mean square (rms EMG amplitude, autoregressive (AR model coefficients and waveform length. Support Vector Machines (SVM was employed to extract classes of different force intensity from the sEMG signals. After assessing the off-line performance of the used classification technique, the WEP was used to validate in real-time the proposed classification scheme. Results The data gathered from the volunteers were divided into two sets, one with nineteen classes and the second with thirteen classes. Each set of data was further divided into training and testing data. It was observed that the average testing accuracy in the case of nineteen classes was about 88% whereas the average accuracy in the case of thirteen classes reached about 96%. Classification and control algorithm implemented in the WEP was executed in less than 125 ms. Conclusions The results of this study showed that

  18. EMG activity and neuronal activity in the internal globus pallidus (GPi) and their interaction are different between hemiballismus and apomorphine induced dyskinesias of Parkinson's disease (AID).

    Science.gov (United States)

    Zhao, L; Verhagen-Metman, L; Kim, J H; Liu, C C; Lenz, F A

    2015-04-07

    The nature of electromyogram (EMG) activity and its relationship to neuronal activity in the internal globus pallidus (GPi) have not previously been studied in hyperkinetic movement disorders. We now test the hypothesis that GPi spike trains are cross-correlated with EMG activity during apomorphine-induced dyskinesias of Parkinson's disease (AID), and Hemiballism. We have recorded these two signals during awake stereotactic pallidal surgeries and analyzed them by cross-correlation of the raw signals and of peaks of activity occurring in those signals. EMG signals in Hemiballism usually consist of 'sharp' activity characterized by peaks of activity with low levels of activity between peaks, and by co-contraction between antagonistic muscles. Less commonly, EMG in Hemiballism shows 'non-sharp' EMG activity with substantial EMG activity between peaks; 'non-sharp' EMG activity is more common in AID. Therefore, these hyperkinetic disorders show substantial differences in peripheral (EMG) activity, although both kinds of activity can occur in both disorders. Since GPi spike×EMG spectral and time domain functions demonstrated inconsistent cross-correlation in both disorders, we studied peaks of activity in GPi neuronal and in EMG signals. The peaks of GPi activity commonly show prolonged cross-correlation with peaks of EMG activity, which suggests that GPi peaks are related to the occurrence of EMG peaks, perhaps by transmission of GPi activity to the periphery. In Hemiballism, the presence of direct GPi peak×EMG peak cross-correlations at the site where lesions relieve these disorders is evidence that gradual changes in peak GPi neuronal activity are directly involved in Hemiballism. Copyright © 2015. Published by Elsevier B.V.

  19. A critical period of corticomuscular and EMG-EMG coherence detection in healthy infants aged 9-25 weeks.

    Science.gov (United States)

    Ritterband-Rosenbaum, Anina; Herskind, Anna; Li, Xi; Willerslev-Olsen, Maria; Olsen, Mikkel Damgaard; Farmer, Simon Francis; Nielsen, Jens Bo

    2017-04-15

    The early postnatal development of functional corticospinal connections in human infants is not fully clarified. Corticospinal drive to upper and lower limb muscle shows developmental changes with an increased functional coupling in infants between 9 and 25 weeks in the beta frequency band. The changes in functional coupling coincide with the developmental period where fidgety movements are present in healthy infants. Data support a possible sensitive period where functional connections between corticospinal tract fibres and spinal motoneurones undergo activity-dependent reorganization. The early postnatal development of functional corticospinal connections in human infants is not fully clarified. We used EEG and EMG to investigate the development of corticomuscular and intramuscular coherence as indicators of functional corticospinal connectivity in healthy infants aged 1-66 weeks. EEG was recorded over leg and hand area of motor cortex. EMG recordings were made from right ankle dorsiflexor and right wrist extensor muscles. Quantification of the amount of corticomuscular coherence in the 20-40 Hz frequency band showed a significantly larger coherence for infants aged 9-25 weeks compared to younger and older infants. Coherence between paired EMG recordings from tibialis anterior muscle in the 20-40 Hz frequency band was also significantly larger for the 9-25 week age group. A low-amplitude, broad-duration (40-50 ms) central peak of EMG-EMG synchronization was observed for infants younger than 9 weeks, whereas a short-lasting (10-20 ms) central peak was observed for EMG-EMG synchronization in older infants. This peak was largest for infants aged 9-25 weeks. These data suggest that the corticospinal drive to lower and upper limb muscles shows significant developmental changes with an increase in functional coupling in infants aged 9-25 weeks, a period which coincides partly with the developmental period of normal fidgety movements. We propose that these

  20. Lower extremity EMG-driven modeling of walking with automated adjustment of musculoskeletal geometry.

    Science.gov (United States)

    Meyer, Andrew J; Patten, Carolynn; Fregly, Benjamin J

    2017-01-01

    Neuromusculoskeletal disorders affecting walking ability are often difficult to manage, in part due to limited understanding of how a patient's lower extremity muscle excitations contribute to the patient's lower extremity joint moments. To assist in the study of these disorders, researchers have developed electromyography (EMG) driven neuromusculoskeletal models utilizing scaled generic musculoskeletal geometry. While these models can predict individual muscle contributions to lower extremity joint moments during walking, the accuracy of the predictions can be hindered by errors in the scaled geometry. This study presents a novel EMG-driven modeling method that automatically adjusts surrogate representations of the patient's musculoskeletal geometry to improve prediction of lower extremity joint moments during walking. In addition to commonly adjusted neuromusculoskeletal model parameters, the proposed method adjusts model parameters defining muscle-tendon lengths, velocities, and moment arms. We evaluated our EMG-driven modeling method using data collected from a high-functioning hemiparetic subject walking on an instrumented treadmill at speeds ranging from 0.4 to 0.8 m/s. EMG-driven model parameter values were calibrated to match inverse dynamic moments for five degrees of freedom in each leg while keeping musculoskeletal geometry close to that of an initial scaled musculoskeletal model. We found that our EMG-driven modeling method incorporating automated adjustment of musculoskeletal geometry predicted net joint moments during walking more accurately than did the same method without geometric adjustments. Geometric adjustments improved moment prediction errors by 25% on average and up to 52%, with the largest improvements occurring at the hip. Predicted adjustments to musculoskeletal geometry were comparable to errors reported in the literature between scaled generic geometric models and measurements made from imaging data. Our results demonstrate that with

  1. Agreement between clinical and portable EMG/ECG diagnosis of sleep bruxism.

    Science.gov (United States)

    Castroflorio, T; Bargellini, A; Rossini, G; Cugliari, G; Deregibus, A; Manfredini, D

    2015-10-01

    The aim of this study was to compare clinical sleep bruxism (SB) diagnosis with an instrumental diagnosis obtained with a device providing electromyography/electrocardiography (EMG/ECG) recordings. Forty-five (N = 45) subjects (19 males and 26 females, mean age 28 ± 11 years) were selected among patients referring to the Gnathology Unit of the Dental School of the University of Torino. An expert clinician assessed the presence of SB based on the presence of one or more signs/symptoms (i.e., transient jaw muscle pain in the morning, muscle fatigue at awakening, presence of tooth wear, masseter hypertrophy). Furthermore, all participants underwent an instrumental recording at home with a portable device (Bruxoff; OT Bioelettronica, Torino, Italy) allowing a simultaneous recording of EMG signals from both the masseter muscles as well as heart frequency. Statistical procedures were performed with the software Statistical Package for the Social Science v. 20.0 (SPSS 20.0; IBM, Milan, Italy). Based on the EMG/ECG analysis, 26 subjects (11 males, 15 females, mean age 28 ± 10 years) were diagnosed as sleep bruxers, whilst 19 subjects (7 males, 12 females, mean age 30 ± 10 years) were diagnosed as non-bruxers. The correlation between the clinical and EMG/ECG SB diagnoses was low (ϕ value = 0.250), with a 62.2% agreement (28/45 subjects) between the two approaches (kappa = 0.248). Assuming instrumental EMG/ECG diagnosis as the standard of reference for definite SB diagnosis in this investigation, the false-positive and false-negative rates were unacceptable for all clinical signs/symptoms. In conclusion, findings from clinical assessment are not related with SB diagnosis performed with a portable EMG/ECG recorder. © 2015 John Wiley & Sons Ltd.

  2. Adaptations of upper trapezius muscle activity during sustained contractions in women with fibromyalgia

    DEFF Research Database (Denmark)

    Falla, Deborah Lorraine; Andersen, Helle; Danneskiold-Samsøe, Bente

    2010-01-01

    The study compared the distribution of electromyographic (EMG) signal amplitude in the upper trapezius muscle in 10 women with fibromyalgia and in 10 healthy women before and after experimentally-induced muscle pain. Surface EMG signals were recorded over the right upper trapezius muscle with a 10...

  3. Adaptations of upper trapezius muscle activity during sustained contractions in women with fibromyalgia

    DEFF Research Database (Denmark)

    Falla, Deborah Lorraine; Andersen, Helle; Danneskiold-Samsøe, Bente

    2010-01-01

    The study compared the distribution of electromyographic (EMG) signal amplitude in the upper trapezius muscle in 10 women with fibromyalgia and in 10 healthy women before and after experimentally-induced muscle pain. Surface EMG signals were recorded over the right upper trapezius muscle with a 1...

  4. Electromyographic Control of a Hands-Free Electrolarynx Using Neck Strap Muscles

    Science.gov (United States)

    Kubert, Heather L.; Stepp, Cara E.; Zeitels, Steven M.; Gooey, John E.; Walsh, Michael J.; Prakash, S. R.; Hillman, Robert E.; Heaton, James T.

    2009-01-01

    Three individuals with total laryngectomy were studied for their ability to control a hands-free electrolarynx (EL) using neck surface electromyography (EMG) for on/off and pitch modulation. The laryngectomy surgery of participants was modified to preserve neck strap musculature for EMG-based EL control (EMG-EL), with muscles on one side…

  5. The influence of mental fatigue on facial EMG activity during a simulated workday

    OpenAIRE

    Veldhuizen, I.J.T.; Gaillard, A.W.K.; de Vries, J.

    2003-01-01

    The present study investigated whether facial EMG measures are sensitive to the effects of fatigue. EMG activity of the corrugator and frontalis muscles was recorded during and after a simulated workday. Fatigue was evaluated in four ways: (a) the building up of fatigue effects during the workday, (b) the building up of fatigue during a test period, (c) examination of after-effects of the workday in two test sessions in the evening, and (d) comparison of subjects with a high-and low-score on ...

  6. Evaluation of Linear Regression Simultaneous Myoelectric Control Using Intramuscular EMG.

    Science.gov (United States)

    Smith, Lauren H; Kuiken, Todd A; Hargrove, Levi J

    2016-04-01

    The objective of this study was to evaluate the ability of linear regression models to decode patterns of muscle coactivation from intramuscular electromyogram (EMG) and provide simultaneous myoelectric control of a virtual 3-DOF wrist/hand system. Performance was compared to the simultaneous control of conventional myoelectric prosthesis methods using intramuscular EMG (parallel dual-site control)-an approach that requires users to independently modulate individual muscles in the residual limb, which can be challenging for amputees. Linear regression control was evaluated in eight able-bodied subjects during a virtual Fitts' law task and was compared to performance of eight subjects using parallel dual-site control. An offline analysis also evaluated how different types of training data affected prediction accuracy of linear regression control. The two control systems demonstrated similar overall performance; however, the linear regression method demonstrated improved performance for targets requiring use of all three DOFs, whereas parallel dual-site control demonstrated improved performance for targets that required use of only one DOF. Subjects using linear regression control could more easily activate multiple DOFs simultaneously, but often experienced unintended movements when trying to isolate individual DOFs. Offline analyses also suggested that the method used to train linear regression systems may influence controllability. Linear regression myoelectric control using intramuscular EMG provided an alternative to parallel dual-site control for 3-DOF simultaneous control at the wrist and hand. The two methods demonstrated different strengths in controllability, highlighting the tradeoff between providing simultaneous control and the ability to isolate individual DOFs when desired.

  7. Three-Dimensional Innervation Zone Imaging from Multi-Channel Surface EMG Recordings.

    Science.gov (United States)

    Liu, Yang; Ning, Yong; Li, Sheng; Zhou, Ping; Rymer, William Z; Zhang, Yingchun

    2015-09-01

    There is an unmet need to accurately identify the locations of innervation zones (IZs) of spastic muscles, so as to guide botulinum toxin (BTX) injections for the best clinical outcome. A novel 3D IZ imaging (3DIZI) approach was developed by combining the bioelectrical source imaging and surface electromyogram (EMG) decomposition methods to image the 3D distribution of IZs in the target muscles. Surface IZ locations of motor units (MUs), identified from the bipolar map of their MU action potentials (MUAPs) were employed as a prior knowledge in the 3DIZI approach to improve its imaging accuracy. The performance of the 3DIZI approach was first optimized and evaluated via a series of designed computer simulations, and then validated with the intramuscular EMG data, together with simultaneously recorded 128-channel surface EMG data from the biceps of two subjects. Both simulation and experimental validation results demonstrate the high performance of the 3DIZI approach in accurately reconstructing the distributions of IZs and the dynamic propagation of internal muscle activities in the biceps from high-density surface EMG recordings.

  8. High energy spectrogram with integrated prior knowledge for EMG-based locomotion classification.

    Science.gov (United States)

    Joshi, Deepak; Nakamura, Bryson H; Hahn, Michael E

    2015-05-01

    Electromyogram (EMG) signal representation is crucial in classification applications specific to locomotion and transitions. For a given signal, classification can be performed using discriminant functions or if-else rule sets, using learning algorithms derived from training examples. In the present work, a spectrogram based approach was developed to classify (EMG) signals for locomotion mode. Spectrograms for each muscle were calculated and summed to develop a histogram. If-else rules were used to classify test data based on a matching score. Prior knowledge of locomotion type reduced class space to exclusive locomotion modes. The EMG data were collected from seven leg muscles in a sample of able-bodied subjects while walking over ground (W), ascending stairs (SA) and the transition between (W-SA). Three muscles with least discriminating power were removed from the original data set to examine the effect on classification accuracy. Initial classification error was EMG channels decreased the classification accuracy by 10.8%, 24.3%, and 8.1% for W, W-SA, and SA respectively, and reduced computation time by 42.8%. This approach may be useful in the control of multi-mode assistive devices. Copyright © 2015 IPEM. Published by Elsevier Ltd. All rights reserved.

  9. Generating Human-Like Velocity-Adapted Jumping Gait from sEMG Signals for Bionic Leg’s Control

    Directory of Open Access Journals (Sweden)

    Weiwei Yu

    2017-01-01

    Full Text Available In the case of dynamic motion such as jumping, an important fact in sEMG (surface Electromyogram signal based control on exoskeletons, myoelectric prostheses, and rehabilitation gait is that multichannel sEMG signals contain mass data and vary greatly with time, which makes it difficult to generate compliant gait. Inspired by the fact that muscle synergies leading to dimensionality reduction may simplify motor control and learning, this paper proposes a new approach to generate flexible gait based on muscle synergies extracted from sEMG signal. Two questions were discussed and solved, the first one concerning whether the same set of muscle synergies can explain the different phases of hopping movement with various velocities. The second one is about how to generate self-adapted gait with muscle synergies while alleviating model sensitivity to sEMG transient changes. From the experimental results, the proposed method shows good performance both in accuracy and in robustness for producing velocity-adapted vertical jumping gait. The method discussed in this paper provides a valuable reference for the sEMG-based control of bionic robot leg to generate human-like dynamic gait.

  10. Muscle activity characterization by laser Doppler Myography

    Science.gov (United States)

    Scalise, Lorenzo; Casaccia, Sara; Marchionni, Paolo; Ercoli, Ilaria; Primo Tomasini, Enrico

    2013-09-01

    Electromiography (EMG) is the gold-standard technique used for the evaluation of muscle activity. This technique is used in biomechanics, sport medicine, neurology and rehabilitation therapy and it provides the electrical activity produced by skeletal muscles. Among the parameters measured with EMG, two very important quantities are: signal amplitude and duration of muscle contraction, muscle fatigue and maximum muscle power. Recently, a new measurement procedure, named Laser Doppler Myography (LDMi), for the non contact assessment of muscle activity has been proposed to measure the vibro-mechanical behaviour of the muscle. The aim of this study is to present the LDMi technique and to evaluate its capacity to measure some characteristic features proper of the muscle. In this paper LDMi is compared with standard superficial EMG (sEMG) requiring the application of sensors on the skin of each patient. sEMG and LDMi signals have been simultaneously acquired and processed to test correlations. Three parameters has been analyzed to compare these techniques: Muscle activation timing, signal amplitude and muscle fatigue. LDMi appears to be a reliable and promising measurement technique allowing the measurements without contact with the patient skin.

  11. Real-time intelligent pattern recognition algorithm for surface EMG signals

    Directory of Open Access Journals (Sweden)

    Jahed Mehran

    2007-12-01

    Full Text Available Abstract Background Electromyography (EMG is the study of muscle function through the inquiry of electrical signals that the muscles emanate. EMG signals collected from the surface of the skin (Surface Electromyogram: sEMG can be used in different applications such as recognizing musculoskeletal neural based patterns intercepted for hand prosthesis movements. Current systems designed for controlling the prosthetic hands either have limited functions or can only be used to perform simple movements or use excessive amount of electrodes in order to achieve acceptable results. In an attempt to overcome these problems we have proposed an intelligent system to recognize hand movements and have provided a user assessment routine to evaluate the correctness of executed movements. Methods We propose to use an intelligent approach based on adaptive neuro-fuzzy inference system (ANFIS integrated with a real-time learning scheme to identify hand motion commands. For this purpose and to consider the effect of user evaluation on recognizing hand movements, vision feedback is applied to increase the capability of our system. By using this scheme the user may assess the correctness of the performed hand movement. In this work a hybrid method for training fuzzy system, consisting of back-propagation (BP and least mean square (LMS is utilized. Also in order to optimize the number of fuzzy rules, a subtractive clustering algorithm has been developed. To design an effective system, we consider a conventional scheme of EMG pattern recognition system. To design this system we propose to use two different sets of EMG features, namely time domain (TD and time-frequency representation (TFR. Also in order to decrease the undesirable effects of the dimension of these feature sets, principle component analysis (PCA is utilized. Results In this study, the myoelectric signals considered for classification consists of six unique hand movements. Features chosen for EMG signal

  12. A non-MVC EMG normalization technique for the trunk musculature: Part 1. Method development.

    Science.gov (United States)

    Marras, W S; Davis, K G

    2001-02-01

    Normalization of muscle activity has been commonly used to determine the amount of force exerted by a muscle. The most widely used reference point for normalization is the maximum voluntary contraction (MVC). However, MVCs are often subjective, and potentially limited by sensation of pain in injured individuals. The objective of the current study was to develop a normalization technique that predicts an electromyographic (EMG) reference point from sub-maximal exertions. Regression equations predicting maximum exerted trunk moments were developed from anthropometric measurements of 120 subjects. In addition, 20 subjects performed sub-maximal and maximal exertions to determine the necessary characteristic exertions needed for normalization purposes. For most of the trunk muscles, a highly linear relationship was found between EMG muscle activity and trunk moment exerted. This analysis determined that an EMG-moment reference point can be obtained via a set of sub-maximal exertions in combination with a predicted maximal exertion (expected maximum contraction or EMC) based upon anthropometric measurements. This normalization technique overcomes the limitations of the subjective nature for the MVC method providing a viable assessment method of individuals with a low back injury or those unwilling to exert an MVC as well as could be extended to other joints/muscles.

  13. Surface EMG activity during REM sleep in Parkinson's disease correlates with disease severity.

    Science.gov (United States)

    Chahine, Lama M; Kauta, Shilpa R; Daley, Joseph T; Cantor, Charles R; Dahodwala, Nabila

    2014-07-01

    Over 40% of individuals with Parkinson's disease (PD) have rapid eye movement sleep behavior disorder (RBD). This is associated with excessive sustained (tonic) or intermittent (phasic) muscle activity instead of the muscle atonia normally seen during REM sleep. We examined characteristics of manually-quantitated surface EMG activity in PD to ascertain whether the extent of muscle activity during REM sleep is associated with specific clinical features and measures of disease severity. In a convenience sample of outpatients with idiopathic PD, REM sleep behavior disorder was diagnosed based on clinical history and polysomnogram, and severity was measured using the RBD sleep questionnaire. Surface EMG activity in the mentalis, extensor muscle group of the forearms, and anterior tibialis was manually quantitated. Percentage of REM time with excessive tonic or phasic muscle activity was calculated and compared across PD and RBD characteristics. Among 65 patients, 31 had confirmed RBD. In univariate analyses, higher amounts of surface EMG activity were associated with longer PD disease duration (srho = 0.34; p = 0.006) and greater disease severity (p REM sleep was associated with severity of both PD and RBD. This measure may be useful as a PD biomarker and, if confirmed, may aid in determining which PD patients warrant treatment for their dream enactment to reduce risk of injury. Copyright © 2014 Elsevier Ltd. All rights reserved.

  14. Low-cost assistive device for hand gesture recognition using sEMG

    Science.gov (United States)

    Kainz, Ondrej; Cymbalák, Dávid; Kardoš, Slavomír.; Fecil'ak, Peter; Jakab, František

    2016-07-01

    In this paper a low-cost solution for surface EMG (sEMG) signal retrieval is presented. The principal goal is to enable reading the temporal parameters of muscles activity by a computer device, with its further processing. Paper integrates design and deployment of surface electrodes and amplifier following the prior researches. Bearing in mind the goal of creating low-cost solution, the Arduino micro-controller was utilized for analog-to-digital conversion and communication. The software part of the system employs support vector machine (SVM) to classify the EMG signal, as acquired from sensors. Accuracy of the proposed solution achieves over 90 percent for six hand movements. Proposed solution is to be tested as an assistive device for several cases, involving people with motor disabilities and amputees.

  15. EMG monitoring during functional non-surgical therapy of Achilles tendon rupture.

    Science.gov (United States)

    Hüfner, Tobias; Wohifarth, Kai; Fink, Matthias; Thermann, H; Rollnik, Jens D

    2002-07-01

    After surgical therapy of Achilles tendon rupture, neuromuscular changes may persist, even one year after surgery. We were interested whether these changes are also evident following a non-surgical functional therapy (Variostabil therapy boot/Adidas). Twenty-one patients with complete Achilles tendon rupture were enrolled in the study (mean age 38.5 years, range 24 to 60; 18 men, three women) and followed-up clinically and with surface EMG of the gastrocnemius muscles after four, eight, 12 weeks, and one year after rupture. EMG differences between the affected and non-affected side could only be observed at baseline and after four weeks following Achilles tendon rupture. The results from our study show that EMG changes are not found following non-surgical functional therapy.

  16. Influence of different attentional focus on EMG amplitude and contraction duration during the bench press at different speeds.

    Science.gov (United States)

    Calatayud, Joaquin; Vinstrup, Jonas; Jakobsen, Markus D; Sundstrup, Emil; Colado, Juan Carlos; Andersen, Lars L

    2017-08-10

    The purpose of this study was to investigate whether using different focus affects electromyographic (EMG) amplitude and contraction duration during bench press performed at explosive and controlled speeds. Eighteen young male individuals were familiarized with the procedure and performed the one-maximum repetition (1RM) test in the first session. In the second session, participants performed the bench press exercise at 50% of the 1RM with 3 different attentional focuses (regular focus on moving the load vs contracting the pectoralis vs contracting the triceps) at 2 speed conditions (controlled vs maximal speed). During the controlled speed condition, focusing on using either the pectoralis or the triceps muscles increased pectoralis normalized EMG (nEMG) by 6% (95% CI 3-8%; p = 0.0001) and 4% nEMG (95% CI 1-7%; p = 0.0096), respectively, compared with the regular focus condition. Triceps activity was increased by 4% nEMG (95% CI 0-7%; p = 0.0308) at the controlled speed condition during the triceps focus. During the explosive speed condition, the use of different focuses had no effect. The different attentional focus resulted in comparable contraction duration for the measured muscles when the exercise was performed explosively. Using internal focus to increase EMG amplitude seems to function only during conditions of controlled speed.

  17. Surface EMG Decomposition Based on K-means Clustering and Convolution Kernel Compensation

    Science.gov (United States)

    Ning, Yong; Zhu, Xiangjun; Zhu, Shanan; Zhang, Yingchun

    2015-01-01

    A new approach has been developed by combining the K-mean clustering (KMC) method and a modified convolution kernel compensation (CKC) method for multi-channel surface electromyogram (EMG) decomposition. The KMC method was first utilized to cluster vectors of observations at different time instants and then estimate the initial innervation pulse train (IPT). The CKC method, modified with a novel multi-step iterative process, was conducted to update the estimated IPT. The performance of the proposed K-means clustering - Modified CKC (KmCKC) approach was evaluated by reconstructing IPTs from both simulated and experimental surface EMG signals. The KmCKC approach successfully reconstructed all 10 IPTs from the simulated surface EMG signals with true positive rates (TPR) of over 90% with a low signal-to-noise ratio (SNR) of −10dB. Over 10 motor units were also successfully extracted from the 64-channel experimental surface EMG signals of the first dorsal interosseous (FDI) muscles when a contraction force was held at 8 N by using the KmCKC approach. A ‘two-source’ test was further conducted with 64-channel surface EMG signals. The high percentage of common MUs and common pulses (over 92% at all force levels) between the IPTs reconstructed from the two independent groups of surface EMG signals demonstrates the reliability and capability of the proposed KmCKC approach in multi-channel surface EMG decomposition. Results from both simulated and experimental data are consistent and confirm that the proposed KmCKC approach can successfully reconstruct IPTs with high accuracy at different levels of contraction. PMID:25486655

  18. Surface EMG decomposition based on K-means clustering and convolution kernel compensation.

    Science.gov (United States)

    Ning, Yong; Zhu, Xiangjun; Zhu, Shanan; Zhang, Yingchun

    2015-03-01

    A new approach has been developed by combining the K-mean clustering (KMC) method and a modified convolution kernel compensation (CKC) method for multichannel surface electromyogram (EMG) decomposition. The KMC method was first utilized to cluster vectors of observations at different time instants and then estimate the initial innervation pulse train (IPT). The CKC method, modified with a novel multistep iterative process, was conducted to update the estimated IPT. The performance of the proposed K-means clustering-Modified CKC (KmCKC) approach was evaluated by reconstructing IPTs from both simulated and experimental surface EMG signals. The KmCKC approach successfully reconstructed all 10 IPTs from the simulated surface EMG signals with true positive rates (TPR) of over 90% with a low signal-to-noise ratio (SNR) of -10 dB. More than 10 motor units were also successfully extracted from the 64-channel experimental surface EMG signals of the first dorsal interosseous (FDI) muscles when a contraction force was held at 8 N by using the KmCKC approach. A "two-source" test was further conducted with 64-channel surface EMG signals. The high percentage of common MUs and common pulses (over 92% at all force levels) between the IPTs reconstructed from the two independent groups of surface EMG signals demonstrates the reliability and capability of the proposed KmCKC approach in multichannel surface EMG decomposition. Results from both simulated and experimental data are consistent and confirm that the proposed KmCKC approach can successfully reconstruct IPTs with high accuracy at different levels of contraction.

  19. An EMG-controlled neuroprosthesis for daily upper limb support: a preliminary study.

    Science.gov (United States)

    Ambrosini, Emilia; Ferrante, Simona; Tibiletti, Marta; Schauer, Thomas; Klauer, Christian; Ferrigno, Giancarlo; Pedrocchi, Alessandra

    2011-01-01

    MUNDUS is an assistive platform for recovering direct interaction capability of severely impaired people based on upper limb motor functions. Its main concept is to exploit any residual control of the end-user, thus being suitable for long term utilization in daily activities. MUNDUS integrates multimodal information (EMG, eye tracking, brain computer interface) to control different actuators, such as a passive exoskeleton for weight relief, a neuroprosthesis for arm motion and small motors for grasping. Within this project, the present work integreted a commercial passive exoskeleton with an EMG-controlled neuroprosthesis for supporting hand-to-mouth movements. Being the stimulated muscle the same from which the EMG was measured, first it was necessary to develop an appropriate digital filter to separate the volitional EMG and the stimulation response. Then, a control method aimed at exploiting as much as possible the residual motor control of the end-user was designed. The controller provided a stimulation intensity proportional to the volitional EMG. An experimental protocol was defined to validate the filter and the controller operation on one healthy volunteer. The subject was asked to perform a sequence of hand-to-mouth movements holding different loads. The movements were supported by both the exoskeleton and the neuroprosthesis. The filter was able to detect an increase of the volitional EMG as the weight held by the subject increased. Thus, a higher stimulation intensity was provided in order to support a more intense exercise. The study demonstrated the feasibility of an EMG-controlled neuroprosthesis for daily upper limb support on healthy subjects, providing a first step forward towards the development of the final MUNDUS platform.

  20. Amplitude and frequency changes in surface EMG of biceps femoris during five days Bruce Protocol treadmill test.

    Science.gov (United States)

    Jamaluddin, Fauzani N; Ahmad, Siti A; Noor, Samsul Bahari Mohd; Hassan, Wan Zuha Wan; Yaakob, Azhar; Adam, Yunus; Ali, Sawal H M

    2015-01-01

    Electromyography (EMG) is one of the indirect tools in indexing fatigue. Fatigue can be detected when there are changes on amplitude and frequency. However, various outcomes from literature make researchers conclude that EMG is not a reliable tool to measure fatigue. This paper investigates EMG behavior of biceps femoris in median frequency and mean absolute value during five days of Bruce Protocol treadmill test. Before that, surface EMG signals are filtered using band pass filter cut-off at 20-500Hz and are de-noised using db45 1-decimated wavelet transform. Five participants achieved more than 85% of their maximal heart rate during the running activity. The authors also consider other markers of fatigue such as performance, muscle soreness and lethargy as indicators to adaptation and maladaptation conditions. Result shows that turning points of median frequency and mean absolute value are very significant in indexing fatigue and indicators to adaptation of resistive training.

  1. Validity and feasibility of the EMG direct observation tool (EMG-DOT).

    Science.gov (United States)

    Leep Hunderfund, Andrea N; Rubin, Devon I; Laughlin, Ruple S; Sorenson, Eric J; Watson, James C; Jones, Lyell K; Juul, Dorthea; Park, Yoon Soo

    2016-04-26

    To develop a new workplace-based EMG direct observation tool (EMG-DOT) and gather validity evidence supporting its use for assessing electrodiagnostic skills among postgraduate medical trainees. The EMG-DOT was developed by experts using an iterative process. Validity evidence from content, response process, internal structure, relations to other variables, and consequences of testing was collected during the 2013-2014 academic year. Of 3,412 studies performed by trainees during the study period, 299 (9%) were assessed using the EMG-DOT. Of these, 203 (68%) involved a physician rater and 96 (32%) involved a technician rater. The 14-item EMG-DOT had excellent internal-consistency reliability (Cronbach α 0.94). Correlations between individual items and criterion-referenced global ratings of performance ranged from 0.36 to 0.72 (all p EMG rotation (p EMG-DOT improved the quality of care provided to patients in 58% (133/230). Trainees were "satisfied" or "very satisfied" with the observational assessment exercise in 96% of encounters (234/243). This study provides validity evidence supporting the use of EMG-DOT scores to assess electrodiagnostic skills of residents and fellows. The EMG-DOT can be used to inform milestone-based assessments of trainee performance in neurology, child neurology, physical medicine and rehabilitation, neuromuscular, and clinical neurophysiology training programs. © 2016 American Academy of Neurology.

  2. Quantification of dynamic EMG patterns during gait in children with cerebral palsy.

    Science.gov (United States)

    Bojanic, Dubravka M; Petrovacki-Balj, Bojana D; Jorgovanovic, Nikola D; Ilic, Vojin R

    2011-06-15

    Our goal was to simplify the representation and interpretation of surface electromyographic (EMG) activity during gait to develop a clinical method for evaluating gait disabilities in children with cerebral palsy (CP). EMG was recorded from four muscles of a lower extremity. Gait cycles were tracked from one force-sensing resistor signal that was recorded synchronously with EMG. The method is based on the comparison of a patient's dynamic EMG envelope shapes and the normative gait-related patterns (norms). Developed norms were based on EMG data obtained in 10 healthy children. Due to newly introduced techniques for time and amplitude normalization, norms were developed regardless of differences in subject age, gender, basic gait parameters and the EMG measurement process. The proposed gait metric quantifies the similarity between a patient's gait-related patterns and norms by a single global value suitable for gait analysis in general, including a detailed analysis using the 10 partial values. The gait metric was experimentally validated with a control group of healthy children and a group of children with CP with different degrees of motor deficits. Gait metric values obtained in children from the control group are high for all muscles, which means that gait-related patterns are close to norms, whereas in children with CP the higher the degree of motor deficit, the lower the gait metric values. The method could be a very useful clinical tool for the recognition and tracking of motor disorders of the lower extremities in children with CP as well as many other neuromotor pathologies. Copyright © 2011 Elsevier B.V. All rights reserved.

  3. Long-term recording of external urethral sphincter EMG activity in unanesthetized, unrestrained rats.

    Science.gov (United States)

    LaPallo, Brandon K; Wolpaw, Jonathan R; Chen, Xiang Yang; Carp, Jonathan S

    2014-08-15

    The external urethral sphincter muscle (EUS) plays an important role in urinary function and often contributes to urinary dysfunction. EUS study would benefit from methodology for longitudinal recording of electromyographic activity (EMG) in unanesthetized animals, but this muscle is a poor substrate for chronic intramuscular electrodes, and thus the required methodology has not been available. We describe a method for long-term recording of EUS EMG by implantation of fine wires adjacent to the EUS that are secured to the pubic bone. Wires pass subcutaneously to a skull-mounted plug and connect to the recording apparatus by a flexible cable attached to a commutator. A force transducer-mounted cup under a metabolic cage collected urine, allowing recording of EUS EMG and voided urine weight without anesthesia or restraint. Implant durability permitted EUS EMG recording during repeated (up to 3 times weekly) 24-h sessions for more than 8 wk. EMG and voiding properties were stable over weeks 2-8. The degree of EUS phasic activity (bursting) during voiding was highly variable, with an average of 25% of voids not exhibiting bursting. Electrode implantation adjacent to the EUS yielded stable EMG recordings over extended periods and eliminated the confounding effects of anesthesia, physical restraint, and the potential for dislodgment of the chronically implanted intramuscular electrodes. These results show that micturition in unanesthetized, unrestrained rats is usually, but not always, associated with EUS bursting. This methodology is applicable to studying EUS behavior during progression of gradually evolving disease and injury models and in response to therapeutic interventions. Copyright © 2014 the American Physiological Society.

  4. sEMG during Whole-Body Vibration Contains Motion Artifacts and Reflex Activity.

    Science.gov (United States)

    Lienhard, Karin; Cabasson, Aline; Meste, Olivier; Colson, Serge S

    2015-03-01

    The purpose of this study was to determine whether the excessive spikes observed in the surface electromyography (sEMG) spectrum recorded during whole-body vibration (WBV) exercises contain motion artifacts and/or reflex activity. The occurrence of motion artifacts was tested by electrical recordings of the patella. The involvement of reflex activity was investigated by analyzing the magnitude of the isolated spikes during changes in voluntary background muscle activity. Eighteen physically active volunteers performed static squats while the sEMG was measured of five lower limb muscles during vertical WBV using no load and an additional load of 33 kg. In order to record motion artifacts during WBV, a pair of electrodes was positioned on the patella with several layers of tape between skin and electrodes. Spectral analysis of the patella signal revealed recordings of motion artifacts as high peaks at the vibration frequency (fundamental) and marginal peaks at the multiple harmonics were observed. For the sEMG recordings, the root mean square of the spikes increased with increasing additional loads (p activity might be contained in the isolated spikes, as identical behavior has been found for stretch reflex responses evoked during direct vibration. In conclusion, the spikes visible in the sEMG spectrum during WBV exercises contain motion artifacts and possibly reflex activity. Key pointsThe spikes observed in the sEMG spectrum during WBV exercises contain motion artifacts and possibly reflex activityThe motion artifacts are more pronounced in the first spike than the following spikes in the sEMG spectrumReflex activity during WBV exercises is enhanced with an additional load of approximately 50% of the body mass.

  5. Surface EMG signals based motion intent recognition using multi-layer ELM

    Science.gov (United States)

    Wang, Jianhui; Qi, Lin; Wang, Xiao

    2017-11-01

    The upper-limb rehabilitation robot is regard as a useful tool to help patients with hemiplegic to do repetitive exercise. The surface electromyography (sEMG) contains motion information as the electric signals are generated and related to nerve-muscle motion. These sEMG signals, representing human's intentions of active motions, are introduced into the rehabilitation robot system to recognize upper-limb movements. Traditionally, the feature extraction is an indispensable part of drawing significant information from original signals, which is a tedious task requiring rich and related experience. This paper employs a deep learning scheme to extract the internal features of the sEMG signals using an advanced Extreme Learning Machine based auto-encoder (ELMAE). The mathematical information contained in the multi-layer structure of the ELM-AE is used as the high-level representation of the internal features of the sEMG signals, and thus a simple ELM can post-process the extracted features, formulating the entire multi-layer ELM (ML-ELM) algorithm. The method is employed for the sEMG based neural intentions recognition afterwards. The case studies show the adopted deep learning algorithm (ELM-AE) is capable of yielding higher classification accuracy compared to the Principle Component Analysis (PCA) scheme in 5 different types of upper-limb motions. This indicates the effectiveness and the learning capability of the ML-ELM in such motion intent recognition applications.

  6. A Novel Framework Based on FastICA for High Density Surface EMG Decomposition

    Science.gov (United States)

    Chen, Maoqi; Zhou, Ping

    2015-01-01

    This study presents a progressive FastICA peel-off (PFP) framework for high density surface electromyogram (EMG) decomposition. The novel framework is based on a shift-invariant model for describing surface EMG. The decomposition process can be viewed as progressively expanding the set of motor unit spike trains, which is primarily based on FastICA. To overcome the local convergence of FastICA, a “peel off” strategy (i.e. removal of the estimated motor unit action potential (MUAP) trains from the previous step) is used to mitigate the effects of the already identified motor units, so more motor units can be extracted. Moreover, a constrained FastICA is applied to assess the extracted spike trains and correct possible erroneous or missed spikes. These procedures work together to improve the decomposition performance. The proposed framework was validated using simulated surface EMG signals with different motor unit numbers (30, 70, 91) and signal to noise ratios (SNRs) (20, 10, 0 dB). The results demonstrated relatively large numbers of extracted motor units and high accuracies (high F1-scores). The framework was also tested with 111 trials of 64-channel electrode array experimental surface EMG signals during the first dorsal interosseous (FDI) muscle contraction at different intensities. On average 14.1 ± 5.0 motor units were identified from each trial of experimental surface EMG signals. PMID:25775496

  7. Prediction of distal arm joint angles from EMG and shoulder orientation for prosthesis control.

    Science.gov (United States)

    Akhtar, Aadeel; Hargrove, Levi J; Bretl, Timothy

    2012-01-01

    Current state-of-the-art upper limb myoelectric prostheses are limited by only being able to control a single degree of freedom at a time. However, recent studies have separately shown that the joint angles corresponding to shoulder orientation and upper arm EMG can predict the joint angles corresponding to elbow flexion/extension and forearm pronation/ supination, which would allow for simultaneous control over both degrees of freedom. In this preliminary study, we show that the combination of both upper arm EMG and shoulder joint angles may predict the distal arm joint angles better than each set of inputs alone. Also, with the advent of surgical techniques like targeted muscle reinnervation, which allows a person with an amputation intuitive muscular control over his or her prosthetic, our results suggest that including a set of EMG electrodes around the forearm increases performance when compared to upper arm EMG and shoulder orientation. We used a Time-Delayed Adaptive Neural Network to predict distal arm joint angles. Our results show that our network's root mean square error (RMSE) decreases and coefficient of determination (R(2)) increases when combining both shoulder orientation and EMG as inputs.

  8. Real-time estimation of FES-induced joint torque with evoked EMG : Application to spinal cord injured patients.

    Science.gov (United States)

    Li, Zhan; Guiraud, David; Andreu, David; Benoussaad, Mourad; Fattal, Charles; Hayashibe, Mitsuhiro

    2016-06-22

    Functional electrical stimulation (FES) is a neuroprosthetic technique for restoring lost motor function of spinal cord injured (SCI) patients and motor-impaired subjects by delivering short electrical pulses to their paralyzed muscles or motor nerves. FES induces action potentials respectively on muscles or nerves so that muscle activity can be characterized by the synchronous recruitment of motor units with its compound electromyography (EMG) signal is called M-wave. The recorded evoked EMG (eEMG) can be employed to predict the resultant joint torque, and modeling of FES-induced joint torque based on eEMG is an essential step to provide necessary prediction of the expected muscle response before achieving accurate joint torque control by FES. Previous works on FES-induced torque tracking issues were mainly based on offline analysis. However, toward personalized clinical rehabilitation applications, real-time FES systems are essentially required considering the subject-specific muscle responses against electrical stimulation. This paper proposes a wireless portable stimulator used for estimating/predicting joint torque based on real time processing of eEMG. Kalman filter and recurrent neural network (RNN) are embedded into the real-time FES system for identification and estimation. Prediction results on 3 able-bodied subjects and 3 SCI patients demonstrate promising performances. As estimators, both Kalman filter and RNN approaches show clinically feasible results on estimation/prediction of joint torque with eEMG signals only, moreover RNN requires less computational requirement. The proposed real-time FES system establishes a platform for estimating and assessing the mechanical output, the electromyographic recordings and associated models. It will contribute to open a new modality for personalized portable neuroprosthetic control toward consolidated personal healthcare for motor-impaired patients.

  9. Influence of joint angle on EMG-torque model during constant-posture, quasi-constant-torque contractions.

    Science.gov (United States)

    Liu, Pu; Liu, Lukai; Martel, Francois; Rancourt, Denis; Clancy, Edward A

    2013-10-01

    Electromyogram (EMG)-torque modeling is of value to many different application areas, including ergonomics, clinical biomechanics and prosthesis control. One important aspect of EMG-torque modeling is the ability to account for the joint angle influence. This manuscript describes an experimental study which relates the biceps/triceps surface EMG of 12 subjects to elbow torque at seven joint angles (spanning 45-135°) during constant-posture, quasi-constant-torque contractions. Advanced EMG amplitude (EMGσ) estimation processors (i.e., whitened, multiple-channel) were investigated and three non-linear EMGσ-torque models were evaluated. When EMG-torque models were formed separately for each of the seven distinct joint angles, a minimum "gold standard" error of 4.23±2.2% MVCF90 resulted (i.e., error relative to maximum voluntary contraction at 90° flexion). This model structure, however, did not directly facilitate interpolation across angles. The best model which did so (i.e., parameterized the angle dependence), achieved an error of 4.17±1.7% MVCF90. Results demonstrated that advanced EMGσ processors lead to improved joint torque estimation. We also contrasted models that did vs. did not account for antagonist muscle co-contraction. Models that accounted for co-contraction estimated individual flexion muscle torques that were ∼29% higher and individual extension muscle torques that were ∼68% higher. Copyright © 2013 Elsevier Ltd. All rights reserved.

  10. Open-Box Muscle-Computer Interface: Introduction to Human-Computer Interactions in Bioengineering, Physiology, and Neuroscience Courses

    Science.gov (United States)

    Landa-Jiménez, M. A.; González-Gaspar, P.; Pérez-Estudillo, C.; López-Meraz, M. L.; Morgado-Valle, C.; Beltran-Parrazal, L.

    2016-01-01

    A Muscle-Computer Interface (muCI) is a human-machine system that uses electromyographic (EMG) signals to communicate with a computer. Surface EMG (sEMG) signals are currently used to command robotic devices, such as robotic arms and hands, and mobile robots, such as wheelchairs. These signals reflect the motor intention of a user before the…

  11. Recovery Effect of the Muscle Fatigue by the Magnetic Stimulation

    Science.gov (United States)

    Uchida, Kousuke; Nuruki, Atsuo; Tsujimura, Sei-Ichi; Tamari, Youzou; Yunokuchi, Kazutomo

    The purpose of this study is to investigate the effect of magnetic stimulation for muscle fatigue. The six healthy subjects participated in the experiment with the repetition grasp using a hand dynamometer. The measurement of EMG (electromyography) and MMG (mechanomyography) is performed on the left forearm. All subjects performed MVC (maximum voluntary contraction), and repeated exercise in 80%MVC after the MVC measurement. The repetition task was entered when display muscular strength deteriorated. We used an EMG and MMG for the measurement of the muscle fatigue. Provided EMG and MMG waves were calculated integral calculus value (iEMG, and iMMG). The result of iEMG and iMMG were divided by muscular strength, because we calculate integral calculus value per the unit display muscular strength. The result of our study, we found recovery effect by the magnetic stimulation in voluntarily muscular strength and iEMG. However, we can not found in a figure of iMMG.

  12. Validation of surface EMG as a measure of intravaginal and intra-abdominal activity: implications for biofeedback-assisted Kegel exercises.

    Science.gov (United States)

    Workman, D E; Cassisi, J E; Dougherty, M C

    1993-01-01

    This study validates surface EMG as a measure of pelvic muscle and abdominal activity by showing its high correlation to internal pressure data. Using standardized scores, between-subjects correlation of perineal EMG and intravaginal pressure was r = .75, and the correlation of abdominal EMG and intra-abdominal pressure was r = .72. Discriminant validity was also demonstrated by showing low correlation between standardized abdominal and perineal EMG measurements (r = .10). A repeated measures multivariate analysis of variance demonstrated that visual and auditory biofeedback of EMG during pelvic floor contractions increases intravaginal pressure when compared with trials without biofeedback. Potential benefits of fabric electrodes include reduced invasiveness and risk and the ease with which patients can utilize this technology for home practice.

  13. Does local immersion in thermo-neutral bath influence surface EMG measurements? Results of an experimental trial.

    Science.gov (United States)

    Kalpakcioglu, Banu; Candir, Fatma; Bernateck, Michael; Gutenbrunner, Christoph; Fischer, Michael J

    2009-12-01

    This study investigated the effect of water immersion on surface electromyography (EMG) signals recorded from the brachioradial muscle of 11 healthy subjects, both in a dry environment and a thermo-neutral forearm bath (36 degrees C). EMG measurements were registered in a sitting position, using waterproof electrodes under 3 conditions: relaxed muscle, maximum voluntary isometric contraction (MVC, 1s, grip test) and 70% of the MVC (5 s). In relaxed muscle, mean EMG values were significantly higher under immersion compared to the dry conditions (dry: 5.4+/-3.6 microV; water: 19.5+/-14.9 microV; p=0.014). In maximum voluntary isometric contraction, there was a significant difference, though not in the same direction (dry: 145.9+/-58.9 microV; water: 73.2+/-35.0 microV; p=0.003). Under 70% MVC, there was no difference between wet and dry conditions (dry: 102.4+/-75.0 microV; water: 100.4+/-65.3 microV; p=0.951). Results suggest that dry and underwater conditions influence EMG readings; however, the results are inconsistent. These findings indicate additional influences on resting muscle activity, as well as MVC. Further measurements with other muscle groups and different types of immersion are needed to clarify conflicting observations.

  14. Oxycodone and Dexamethasone for pain management after tonsillectomy: A placebo-controlled EMG assessed clinical trial

    Science.gov (United States)

    Vaiman, Michael; Krakovski, Daniel; Haitov, Zoe

    2011-01-01

    Summary Background Surface electromyographic (sEMG) study of post-tonsillectomy swallow-evoked muscular reactions was performed in order to evaluate the efficacy and safety of oxycodone and dexamethasone in pain management after tonsillectomy. Material/Methods 90 randomly chosen operated adults were divided into three groups. Group 1 (n=30) was treated with OxyContin (Oxycodone) injections; Group 2 (n=30) was treated with Dexacort (Dexamethasone), and Group 3 (n=30) was a placebo group. Pain assessment included visual analogue scale (VAS) pain score and the EMG data like the timing, electric amplitude and graphic patterns of muscular activity during deglutition. We investigated masseter, infrahyoid and submental-submandibular muscles. Records from trapezius muscle were used for control. The results were compared with previously established normative database. The patients were tested 24 h after surgery. The sEMG data were compared with VAS pain score with regard to changes in clinical condition of the patients. Results Analgesia with oxycodone smoothed the recorded sEMG swallow peaks and increases time of deglutition. Dexamethasone normalized muscular activity in deglutition in cases with edema as detected by the EMG records. Statistically significant difference in muscle reactions was detected between the two Groups and the placebo group. Conclusions Application of oxycodone significantly reduces the postoperative pain. Application of dexamethasone after tonsillectomy is advisable because of the reduction of postoperative morbidity while the reduction of the postoperative pain is secondary to the reduction of edema. SEMG might be used as an adjunctive measure of pain behavior via assessment of muscular reactions to pain and to analgesia. PMID:21959624

  15. sEMG during Whole-Body Vibration Contains Motion Artifacts and Reflex Activity

    Directory of Open Access Journals (Sweden)

    Karin Lienhard

    2015-01-01

    Full Text Available The purpose of this study was to determine whether the excessive spikes observed in the surface electromyography (sEMG spectrum recorded during whole-body vibration (WBV exercises contain motion artifacts and/or reflex activity. The occurrence of motion artifacts was tested by electrical recordings of the patella. The involvement of reflex activity was investigated by analyzing the magnitude of the isolated spikes during changes in voluntary background muscle activity. Eighteen physically active volunteers performed static squats while the sEMG was measured of five lower limb muscles during vertical WBV using no load and an additional load of 33 kg. In order to record motion artifacts during WBV, a pair of electrodes was positioned on the patella with several layers of tape between skin and electrodes. Spectral analysis of the patella signal revealed recordings of motion artifacts as high peaks at the vibration frequency (fundamental and marginal peaks at the multiple harmonics were observed. For the sEMG recordings, the root mean square of the spikes increased with increasing additional loads (p < 0.05, and was significantly correlated to the sEMG signal without the spikes of the respective muscle (r range: 0.54 - 0.92, p < 0.05. This finding indicates that reflex activity might be contained in the isolated spikes, as identical behavior has been found for stretch reflex responses evoked during direct vibration. In conclusion, the spikes visible in the sEMG spectrum during WBV exercises contain motion artifacts and possibly reflex activity.

  16. The increase in surface EMG could be a misleading measure of neural adaptation during the early gains in strength.

    Science.gov (United States)

    Arabadzhiev, Todor I; Dimitrov, Vladimir G; Dimitrov, George V

    2014-08-01

    To test the validity of using the increase in surface EMG as a measure of neural adaptation during the early gains in strength. Simulation of EMG signals detected by surface bipolar electrode with 20-mm inter-pole distance at different radial distances from the muscle and longitudinal distances from the end-plate area. The increases in the root mean square (RMS) of the EMG signal due to possible alteration in the neural drive or elevation of the intracellular negative after-potentials, detected in fast fatigable muscle fibres during post-tetanic potentiation and assumed to accompany post-activation potentiation, were compared. Lengthening of the intracellular action potential (IAP) profile due to elevation of the negative after-potentials could affect amplitude characteristics of surface EMG detected at any axial distance stronger than alteration in the neural drive. This was irrespective of the fact that the elevation of IAP negative after-potential was applied to fast fatigable motor units (MUs) only, while changes in frequency of activation (simulating neural drive changes) were applied to all MUs. In deeper muscles, where the fibre-electrode distance was larger, the peripheral effect was more pronounced. The normalization of EMG amplitude characteristics to an M-wave one could result only in partial elimination of peripheral factor influence The increase in RMS of surface EMG during the early gains in strength should not be directly related to the changes in the neural drive. The relatively small but long-lasting elevated free resting calcium after high-resistance strength training could result in force potentiation and EMG increase.

  17. Absolute and relative intrasession reliability of surface EMG variables for voluntary precise forearm movements.

    Science.gov (United States)

    Carius, Daniel; Kugler, Patrick; Kuhwald, Hans-Marten; Wollny, Rainer

    2015-12-01

    The reliability of surface electromyography (EMG) derived parameters is of high importance, but there is distinct lack of studies concerning the reliability during dynamic contractions. Especially Amplitude, Fourier and Wavelet parameter in conjunction have not been tested so far. The interpretation of the EMG variables might be difficult because the movement itself introduces additional factors that affect its characteristics. The aim of this study was to determine the relative and absolute intrasession reliability of electromyographic (EMG) variables of selected arm muscles during concurrent precise elbow extension/flexion movements at different force levels and movement speed. Participants (all-male: n = 17, range 20-32 years) were asked to adapt to a gross-motor visuomotor tracking task (elbow extension/flexion movement) using a custom-built lever arm apparatus. After sufficient adaptation surface electromyography was used to record the electrical activity of mm. biceps brachii, brachioradialis and triceps brachii, and the signal amplitude (RMS [μV]) and the mean frequency of the power spectrum (MNF [Hz]) were computed. Additionally Wavelet analysis was used. Relative reproducibility (intraclass correlation) for signal amplitude, mean frequency of the power spectrum and Wavelet intensity during dynamic contractions was fair to good, independent of force level and movement speed (ICC = 0.71-0.98). The amount of absolute intrasession reliability (coefficient of variation) of EMG variables depends on muscle and force level. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. Evaluation of sonomyography (SMG) for control compared with electromyography (EMG) in a discrete target tracking task.

    Science.gov (United States)

    Guo, Jing-Yi; Zheng, Yong-Ping; Kenney, Laurence P; Xie, Hong-Bo

    2009-01-01

    Most of the commercial upper-limb externally powered prosthetic devices are controlled by electromyography (EMG) signals. We previously proposed using the real-time change of muscle thickness detected using ultrasound, namely sonomyography (SMG), for the control of prostheses. In this study, we compared the performance of subjects using 1-D SMG signal and surface EMG signal, using a discrete target tracking protocol involving a series of letter cancellation tasks. Each task involved using grip force, EMG or SMG from a wrist extensor muscle to move a cursor to one of 5 locations on a computer screen, at the first four of which were located a letter and last of which was a word of "NEXT". The target was defined by the location showing the letter "E" and, once the subject reached this target, they were instructed to "cancel" the E from the screen, using a button operated by the contralateral hand. A paired t-test revealed that the percentage of letters correctly cancelled with force/angle and SMG signal in isometric force control, and with SMG in wrist extension were significantly higher than with EMG (PEMG for prosthetic control.

  19. Robust functional statistics applied to Probability Density Function shape screening of sEMG data.

    Science.gov (United States)

    Boudaoud, S; Rix, H; Al Harrach, M; Marin, F

    2014-01-01

    Recent studies pointed out possible shape modifications of the Probability Density Function (PDF) of surface electromyographical (sEMG) data according to several contexts like fatigue and muscle force increase. Following this idea, criteria have been proposed to monitor these shape modifications mainly using High Order Statistics (HOS) parameters like skewness and kurtosis. In experimental conditions, these parameters are confronted with small sample size in the estimation process. This small sample size induces errors in the estimated HOS parameters restraining real-time and precise sEMG PDF shape monitoring. Recently, a functional formalism, the Core Shape Model (CSM), has been used to analyse shape modifications of PDF curves. In this work, taking inspiration from CSM method, robust functional statistics are proposed to emulate both skewness and kurtosis behaviors. These functional statistics combine both kernel density estimation and PDF shape distances to evaluate shape modifications even in presence of small sample size. Then, the proposed statistics are tested, using Monte Carlo simulations, on both normal and Log-normal PDFs that mimic observed sEMG PDF shape behavior during muscle contraction. According to the obtained results, the functional statistics seem to be more robust than HOS parameters to small sample size effect and more accurate in sEMG PDF shape screening applications.

  20. EMG-based speech recognition using hidden markov models with global control variables.

    Science.gov (United States)

    Lee, Ki-Seung

    2008-03-01

    It is well known that a strong relationship exists between human voices and the movement of articulatory facial muscles. In this paper, we utilize this knowledge to implement an automatic speech recognition scheme which uses solely surface electromyogram (EMG) signals. The sequence of EMG signals for each word is modelled by a hidden Markov model (HMM) framework. The main objective of the work involves building a model for state observation density when multichannel observation sequences are given. The proposed model reflects the dependencies between each of the EMG signals, which are described by introducing a global control variable. We also develop an efficient model training method, based on a maximum likelihood criterion. In a preliminary study, 60 isolated words were used as recognition variables. EMG signals were acquired from three articulatory facial muscles. The findings indicate that such a system may have the capacity to recognize speech signals with an accuracy of up to 87.07%, which is superior to the independent probabilistic model.

  1. An EMG-driven model applied for predicting metabolic energy consumption during movement.

    Science.gov (United States)

    Bisi, Maria Cristina; Stagni, Rita; Houdijk, Han; Gnudi, Gianni

    2011-12-01

    The relationship between mechanical work and metabolic energy cost during movement is not yet clear. Many studies demonstrated the utility of forward-dynamic musculoskeletal models combined with experimental data to address such question. The aim of this study was to evaluate the applicability of a muscle energy expenditure model at whole body level, using an EMG-driven approach. Four participants performed a 5-min squat exercise on unilateral leg press at two different frequencies and two load levels. Data collected were kinematics, EMG, forces and moments under the foot and gas-exchange data. This same task was simulated using a musculoskeletal model, which took EMG and kinematics as inputs and gave muscle forces and muscle energetics as outputs. Model parameters were taken from literature, but maximal isometric muscle force was optimized in order to match predicted joint moments with measured ones. Energy rates predicted by the model were compared with energy consumption measured by the gas-exchange data. Model results on metabolic energy consumption were close to the values obtained through indirect calorimetry. At the higher frequency level, the model underestimated measured energy consumption. This underestimation can be explained with an increase in energy consumption of the non-muscular mass with movement velocity. In conclusion, results obtained in comparing model predictions with experimental data were promising. More research is needed to evaluate this way of computing mechanical and metabolic work. Copyright © 2011 Elsevier Ltd. All rights reserved.

  2. Simultaneous electromyography and 31P nuclear magnetic resonance spectroscopy--with application to muscle fatigue

    DEFF Research Database (Denmark)

    Vestergaard-Poulsen, P; Thomsen, C; Sinkjaer, T

    1992-01-01

    The electromyogram (EMG) is often used to study human muscle fatigue, but the changes in the electromyographic signals during muscle contraction are not well understood in relation to muscle metabolism. The 31P NMR spectroscopy is a semi-quantitative non-invasive method for studying the metabolic...... changes in human muscle. The aim of this study was to develop a method by which EMG and NMR spectroscopy measurements could be performed simultaneously. All measurements were performed in a whole body 1.5 Tesla NMR scanner. A calf muscle ergometer, designed for use in a whole body NMR scanner, was used....... The subject had the left foot strapped to the ergometer. The anterior tibial EMG was recorded by bipolar surface electrodes. A surface coil was strapped to the anterior tibial muscle next to the EMG electrodes. Simultaneous measurements of surface EMG and surface coil 31P NMR spectroscopy were performed...

  3. Fundamental research on the evaluation of muscle activity state

    OpenAIRE

    遠藤, 厚志

    2016-01-01

    This paper describes the fundamental research results obtained by adding the sensory information to the activity state evaluation of muscle movement. The purpose of this study is to show the engineering evaluation results of the activity state of the muscle by sEMG(surface ElectroMyoGraphy) using the visual information that biofeedback is made. No evaluation method has the visual information, from being affected by the auxiliary cooperative muscles, not efficient. How to sEMG and biofeedback ...

  4. A motion-classification strategy based on sEMG-EEG signal combination for upper-limb amputees.

    Science.gov (United States)

    Li, Xiangxin; Samuel, Oluwarotimi Williams; Zhang, Xu; Wang, Hui; Fang, Peng; Li, Guanglin

    2017-01-07

    Most of the modern motorized prostheses are controlled with the surface electromyography (sEMG) recorded on the residual muscles of amputated limbs. However, the residual muscles are usually limited, especially after above-elbow amputations, which would not provide enough sEMG for the control of prostheses with multiple degrees of freedom. Signal fusion is a possible approach to solve the problem of insufficient control commands, where some non-EMG signals are combined with sEMG signals to provide sufficient information for motion intension decoding. In this study, a motion-classification method that combines sEMG and electroencephalography (EEG) signals were proposed and investigated, in order to improve the control performance of upper-limb prostheses. Four transhumeral amputees without any form of neurological disease were recruited in the experiments. Five motion classes including hand-open, hand-close, wrist-pronation, wrist-supination, and no-movement were specified. During the motion performances, sEMG and EEG signals were simultaneously acquired from the skin surface and scalp of the amputees, respectively. The two types of signals were independently preprocessed and then combined as a parallel control input. Four time-domain features were extracted and fed into a classifier trained by the Linear Discriminant Analysis (LDA) algorithm for motion recognition. In addition, channel selections were performed by using the Sequential Forward Selection (SFS) algorithm to optimize the performance of the proposed method. The classification performance achieved by the fusion of sEMG and EEG signals was significantly better than that obtained by single signal source of either sEMG or EEG. An increment of more than 14% in classification accuracy was achieved when using a combination of 32-channel sEMG and 64-channel EEG. Furthermore, based on the SFS algorithm, two optimized electrode arrangements (10-channel sEMG + 10-channel EEG, 10-channel sEMG + 20-channel

  5. Iterative Assessment of Statistically-Oriented and Standard Algorithms for Determining Muscle Onset with Intramuscular Electromyography

    Science.gov (United States)

    2017-12-01

    EMG), is a commonly applied metric in biomechanics. Intramuscular EMG is often used to examine deep musculature and there are currently no studies...assessment of deep musculature or small superficial muscles.4 The onset timing of intramuscular EMG has been used exten- sively to examine the “core muscles...this work , no more than 3 parameters were systematically modified for each algorithm. Statistical Analysis In total, 605 standard and novel algorithm

  6. Lack of effect of acupuncture on electromyographic (EMG) activity--a randomised controlled trial in healthy volunteers.

    Science.gov (United States)

    Tough, Liz

    2006-06-01

    Acupuncture is used clinically to treat muscle spasticity and flaccidity. Claims have been made that acupuncture can affect muscle EMG activity, though there is some doubt about the reliability of these studies. This study's aim was to examine the immediate effects of acupuncture on the EMG activity of the common wrist extensor muscles. Thirty five right-handed healthy volunteers, 17 male and 18 female, aged 18-70 years were recruited from a convenience sample. Five subjects provided reliability data, and the remaining 30 took part in the main study. The study was a crossover, within-subject design, with the interventions counterbalanced. The three conditions were genuine acupuncture to LI4 (Hegu) and LI10 (Shousanli) for 20 minutes, with de qi; inappropriate acupuncture to PC3 (Quze) and PC6 (Neiguan) for 20 minutes; and 20 minutes of a no intervention control. All participants received each condition in random order. The outcome measure was surface EMG activity recorded over the common wrist extensor muscles during a 10 second, sub-maximal, isometric contraction. The average of three readings was used. The reliability of the outcome measurement was assessed in five volunteers selected at random who received repeated EMG recordings without acupuncture. The reliability tests showed the EMG procedure was highly reliable, with an intraclass correlation coefficient (ICC 2,1) of 0.9996 and a standard error of measurement of 0.014 mV. In the main study, paired t tests for the effect of the order of the first two interventions showed no detectable carry-over effect. Freidman analysis of variance found no difference between the three conditions (P=0.573). No meaningful change was detected in EMG activity following acupuncture interventions, but this study provides a sound protocol and normative values on which to plan future research.

  7. Spatial distribution of HD-EMG improves identification of task and force in patients with incomplete spinal cord injury.

    Science.gov (United States)

    Jordanic, Mislav; Rojas-Martínez, Mónica; Mañanas, Miguel Angel; Alonso, Joan Francesc

    2016-04-29

    Recent studies show that spatial distribution of High Density surface EMG maps (HD-EMG) improves the identification of tasks and their corresponding contraction levels. However, in patients with incomplete spinal cord injury (iSCI), some nerves that control muscles are damaged, leaving some muscle parts without an innervation. Therefore, HD-EMG maps in patients with iSCI are affected by the injury and they can be different for every patient. The objective of this study is to investigate the spatial distribution of intensity in HD-EMG recordings to distinguish co-activation patterns for different tasks and effort levels in patients with iSCI. These patterns are evaluated to be used for extraction of motion intention. HD-EMG was recorded in patients during four isometric tasks of the forearm at three different effort levels. A linear discriminant classifier based on intensity and spatial features of HD-EMG maps of five upper-limb muscles was used to identify the attempted tasks. Task and force identification were evaluated for each patient individually, and the reliability of the identification was tested with respect to muscle fatigue and time interval between training and identification. Three feature sets were analyzed in the identification: 1) intensity of the HD-EMG map, 2) intensity and center of gravity of HD-EMG maps and 3) intensity of a single differential EMG channel (gold standard). Results show that the combination of intensity and spatial features in classification identifies tasks and effort levels properly (Acc = 98.8 %; S = 92.5 %; P = 93.2 %; SP = 99.4 %) and outperforms significantly the other two feature sets (p < 0.05). In spite of the limited motor functionality, a specific co-activation pattern for each patient exists for both intensity, and spatial distribution of myoelectric activity. The spatial distribution is less sensitive than intensity to myoelectric changes that occur due to fatigue, and other time

  8. Specific diurnal EMG activity pattern observed in occlusal collapse patients: relationship between diurnal bruxism and tooth loss progression.

    Directory of Open Access Journals (Sweden)

    Shigehisa Kawakami

    Full Text Available AIM: The role of parafunctional masticatory muscle activity in tooth loss has not been fully clarified. This study aimed to reveal the characteristic activity of masseter muscles in bite collapse patients while awake and asleep. MATERIALS AND METHODS: Six progressive bite collapse patients (PBC group, six age- and gender-matched control subjects (MC group, and six young control subjects (YC group were enrolled. Electromyograms (EMG of the masseter muscles were continuously recorded with an ambulatory EMG recorder while patients were awake and asleep. Diurnal and nocturnal parafunctional EMG activity was classified as phasic, tonic, or mixed using an EMG threshold of 20% maximal voluntary clenching. RESULTS: Highly extended diurnal phasic activity was observed only in the PBC group. The three groups had significantly different mean diurnal phasic episodes per hour, with 13.29±7.18 per hour in the PBC group, 0.95±0.97 per hour in the MC group, and 0.87±0.98 per hour in the YC group (p<0.01. ROC curve analysis suggested that the number of diurnal phasic episodes might be used to predict bite collapsing tooth loss. CONCLUSION: Extensive bite loss might be related to diurnal masticatory muscle parafunction but not to parafunction during sleep. CLINICAL RELEVANCE SCIENTIFIC RATIONALE FOR STUDY: Although mandibular parafunction has been implicated in stomatognathic system breakdown, a causal relationship has not been established because scientific modalities to evaluate parafunctional activity have been lacking. PRINCIPAL FINDINGS: This study used a newly developed EMG recording system that evaluates masseter muscle activity throughout the day. Our results challenge the stereotypical idea of nocturnal bruxism as a strong destructive force. We found that diurnal phasic masticatory muscle activity was most characteristic in patients with progressive bite collapse. PRACTICAL IMPLICATIONS: The incidence of diurnal phasic contractions could be used for

  9. Kettlebell swing targets semitendinosus and supine leg curl targets biceps femoris: an EMG study with rehabilitation implications.

    Science.gov (United States)

    Zebis, Mette Kreutzfeldt; Skotte, Jørgen; Andersen, Christoffer H; Mortensen, Peter; Petersen, Højland H; Viskaer, Tine C; Jensen, Tanja L; Bencke, Jesper; Andersen, Lars L

    2013-12-01

    The medial hamstring muscle has the potential to prevent excessive dynamic valgus and external rotation of the knee joint during sports. Thus, specific training targeting the medial hamstring muscle seems important to avoid knee injuries. The aim was to investigate the medial and lateral hamstring muscle activation balance during 14 selected therapeutic exercises. The study design involved single-occasion repeated measures in a randomised manner. Sixteen female elite handball and soccer players with a mean (SD) age of 23 (3) years and no previous history of knee injury participated in the present study. Electromyographic (EMG) activity of the lateral (biceps femoris - BF) and medial (semitendinosus - ST) hamstring muscle was measured during selected strengthening and balance/coordination exercises, and normalised to EMG during isometric maximal voluntary contraction (MVC). A two-way analysis of variance was performed using the mixed procedure to determine whether differences existed in normalised EMG between exercises and muscles. Kettlebell swing and Romanian deadlift targeted specifically ST over BF (Δ17-22%, p<0.05) at very high levels of normalised EMG (73-115% of MVC). In contrast, the supine leg curl and hip extension specifically targeted the BF over the ST (Δ 20-23%, p<0.05) at very high levels of normalised EMG (75-87% of MVC). Specific therapeutic exercises targeting the hamstrings can be divided into ST dominant or BF dominant hamstring exercises. Due to distinct functions of the medial and lateral hamstring muscles, this is an important knowledge in respect to prophylactic training and physical therapist practice.

  10. The Assessment of Muscular Effort, Fatigue, and Physiological Adaptation Using EMG and Wavelet Analysis.

    Directory of Open Access Journals (Sweden)

    Ryan B Graham

    Full Text Available Peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PGC-1α is a transcription factor co-activator that helps coordinate mitochondrial biogenesis within skeletal muscle following exercise. While evidence gleaned from submaximal exercise suggests that intracellular pathways associated with the activation of PGC-1α, as well as the expression of PGC-1α itself are activated to a greater extent following higher intensities of exercise, we have recently shown that this effect does not extend to supramaximal exercise, despite corresponding increases in muscle activation amplitude measured with electromyography (EMG. Spectral analyses of EMG data may provide a more in-depth assessment of changes in muscle electrophysiology occurring across different exercise intensities, and therefore the goal of the present study was to apply continuous wavelet transforms (CWTs to our previous data to comprehensively evaluate: 1 differences in muscle electrophysiological properties at different exercise intensities (i.e. 73%, 100%, and 133% of peak aerobic power, and 2 muscular effort and fatigue across a single interval of exercise at each intensity, in an attempt to shed mechanistic insight into our previous observations that the increase in PGC-1α is dissociated from exercise intensity following supramaximal exercise. In general, the CWTs revealed that localized muscle fatigue was only greater than the 73% condition in the 133% exercise intensity condition, which directly matched the work rate results. Specifically, there were greater drop-offs in frequency, larger changes in burst power, as well as greater changes in burst area under this intensity, which were already observable during the first interval. As a whole, the results from the present study suggest that supramaximal exercise causes extreme localized muscular fatigue, and it is possible that the blunted PGC-1α effects observed in our previous study are the result of fatigue

  11. Muscle activation during selected strength exercises in women with chronic neck muscle pain

    DEFF Research Database (Denmark)

    Andersen, Lars L; Kjaer, Michael; Andersen, Christoffer H

    2008-01-01

    BACKGROUND AND PURPOSE: Muscle-specific strength training has previously been shown to be effective in the rehabilitation of chronic neck muscle pain in women. The aim of this study was to determine the level of activation of the neck and shoulder muscles using surface electromyography (EMG) duri...

  12. Muscle activation during selected strength exercises in women with chronic neck muscle pain

    DEFF Research Database (Denmark)

    Andersen, L.L.; Kjaer, M.; Andersen, C.H.

    2008-01-01

    Background and Purpose. Muscle-specific strength training has previously been shown to be effective in the rehabilitation of chronic neck muscle pain in women. The aim of this stud), was to determine the level of activation of the neck and shoulder muscles using surface electromyography (EMG) (lu...

  13. Locomotor training with body weight support in SCI: EMG improvement is more optimally expressed at a low testing speed.

    Science.gov (United States)

    Meyns, P; Van de Crommert, H W A A; Rijken, H; van Kuppevelt, D H J M; Duysens, J

    2014-12-01

    Case series. To determine the optimal testing speed at which the recovery of the EMG (electromyographic) activity should be assessed during and after body weight supported (BWS) locomotor training. Tertiary hospital, Sint Maartenskliniek, Nijmegen, The Netherlands. Four participants with incomplete chronic SCI were included for BWS locomotor training; one AIS-C and three AIS-D (according to the ASIA (American Spinal Injury Association) Impairment Scale or AIS). All were at least 5 years after injury. The SCI participants were trained three times a week for a period of 6 weeks. They improved their locomotor function in terms of higher walking speed, less BWS and less assistance needed. To investigate which treadmill speed for EMG assessment reflects the functional improvement most adequately, all participants were assessed weekly using the same two speeds (0.5 and 1.5 km h(-1), referred to as low and high speed, respectively) for 6 weeks. The change in root mean square EMG (RMS EMG) was assessed in four leg muscles; biceps femoris, rectus femoris, gastrocnemius medialis and tibialis anterior. The changes in RMS EMG occurred at similar phases of the step cycle for both walking conditions, but these changes were larger when the treadmill was set at a low speed (0.5 km h(-1)). Improvement in gait is feasible with BWS treadmill training even long after injury. The EMG changes after treadmill training are more optimally expressed using a low rather than a high testing treadmill speed.

  14. Single-Channel EMG Classification With Ensemble-Empirical-Mode-Decomposition-Based ICA for Diagnosing Neuromuscular Disorders.

    Science.gov (United States)

    Naik, Ganesh R; Selvan, S Easter; Nguyen, Hung T

    2016-07-01

    An accurate and computationally efficient quantitative analysis of electromyography (EMG) signals plays an inevitable role in the diagnosis of neuromuscular disorders, prosthesis, and several related applications. Since it is often the case that the measured signals are the mixtures of electric potentials that emanate from surrounding muscles (sources), many EMG signal processing approaches rely on linear source separation techniques such as the independent component analysis (ICA). Nevertheless, naive implementations of ICA algorithms do not comply with the task of extracting the underlying sources from a single-channel EMG measurement. In this respect, the present work focuses on a classification method for neuromuscular disorders that deals with the data recorded using a single-channel EMG sensor. The ensemble empirical mode decomposition algorithm decomposes the single-channel EMG signal into a set of noise-canceled intrinsic mode functions, which in turn are separated by the FastICA algorithm. A reduced set of five time domain features extracted from the separated components are classified using the linear discriminant analysis, and the classification results are fine-tuned with a majority voting scheme. The performance of the proposed method has been validated with a clinical EMG database, which reports a higher classification accuracy (98%). The outcome of this study encourages possible extension of this approach to real settings to assist the clinicians in making correct diagnosis of neuromuscular disorders.

  15. LONG-LASTING SUPERNORMAL CONDUCTION-VELOCITY AFTER SUSTAINED MAXIMAL ISOMETRIC CONTRACTION IN HUMAN MUSCLE

    NARCIS (Netherlands)

    VANDERHOEVEN, JH; VANWEERDEN, TW; ZWARTS, MJ

    Local muscle fatigue (1 min maximal voluntary contraction) and recovery were studied by means of surface and invasive EMG on elbow flexors to record the changes in muscle fiber conduction velocity (MFCV), median power frequency (MPF), integrated EMG (IEMG), and force. The main finding was a

  16. Fatigue-associated changes in the electromyogram of the human first dorsal interosseous muscle

    NARCIS (Netherlands)

    Zijdewind, Inge; Zwarts, MJ; Kernell, D

    1999-01-01

    Muscle fatigue is a clinically important symptom, often analyzed using electromyography (EMG). We analyzed fatigue reactions of the first dorsal interosseous muscle (FDI) during a maintained contraction at half-maximal force (1/2-MVC test). EMGs were recorded with large surface electrodes and,

  17. Specific Diurnal EMG Activity Pattern Observed in Occlusal Collapse Patients: Relationship between Diurnal Bruxism and Tooth Loss Progression

    Science.gov (United States)

    Kawakami, Shigehisa; Kumazaki, Yohei; Manda, Yosuke; Oki, Kazuhiro; Minagi, Shogo

    2014-01-01

    Aim The role of parafunctional masticatory muscle activity in tooth loss has not been fully clarified. This study aimed to reveal the characteristic activity of masseter muscles in bite collapse patients while awake and asleep. Materials and Methods Six progressive bite collapse patients (PBC group), six age- and gender-matched control subjects (MC group), and six young control subjects (YC group) were enrolled. Electromyograms (EMG) of the masseter muscles were continuously recorded with an ambulatory EMG recorder while patients were awake and asleep. Diurnal and nocturnal parafunctional EMG activity was classified as phasic, tonic, or mixed using an EMG threshold of 20% maximal voluntary clenching. Results Highly extended diurnal phasic activity was observed only in the PBC group. The three groups had significantly different mean diurnal phasic episodes per hour, with 13.29±7.18 per hour in the PBC group, 0.95±0.97 per hour in the MC group, and 0.87±0.98 per hour in the YC group (pbruxism as a strong destructive force. We found that diurnal phasic masticatory muscle activity was most characteristic in patients with progressive bite collapse. Practical implications The incidence of diurnal phasic contractions could be used for the prognostic evaluation of stomatognathic system stability. PMID:25010348

  18. NEUROFEEDBACK AND EMG TRAINING COMBINING EFFICIENCY STUDY IN 6–9 YEARS OLD ADHD CHILDREN

    OpenAIRE

    Ye. А. Sapina

    2013-01-01

    The research goal was to study neurofeedback and EMG combining training efficiency in ADHD children.To achieve the goal three groups were compared before and after training and six months later. Experimental group included ADHD children 6–9 years old. It was divided into two: group A trained thetabeta ratio and muscle tension decrease simultaneously while group B trained only theta-beta ratio decrease. Control group included healthy children. The results showed significant effect of combined ...

  19. Thinking Outside the Button Box: EMG as a Computer Input Device for Psychological Research

    OpenAIRE

    Crawford, L. Elizabeth; Vavra, Dylan T.; Corbin, Jonathan C.

    2017-01-01

    Experimental psychology research commonly has participants respond to stimuli by pressing buttons or keys. Standard computer input devices constrain the range of motoric responses participants can make, even as the field advances theory about the importance of the motor system in cognitive and social information processing. Here we describe an inexpensive way to use an electromyographic (EMG) signal as a computer input device, enabling participants to control a computer by contracting muscles...

  20. An EMG Keyboard for Forearm Amputees

    Directory of Open Access Journals (Sweden)

    Wenwei Yu

    2003-01-01

    Full Text Available A high-efficiency, easy-to-use input device is not only important for data entry but also for human-computer interaction. To date, there has been little research on input devices with many degrees of freedom (DOF that can be used by the handicapped. This paper presents the development of an electromyography (EMG-based input device for forearm amputees. To overcome the difficulties in analysing EMG and realising high DOF from biosignals, the following were integrated: (1 an online learning method to cope with nonlinearity and the individual difference of EMG signals; (2 a smoothing algorithm to deal with noisy recognition results and transition states; and (3 a modified Huffman coding algorithm to generate the optimal code, taking expected error and input efficiency into consideration. Experiments showed the validity of the system and the possibility for development of a quiet, free-posture (no postural restriction input device with many DOF for users, including forearm amputees.

  1. Analysis of muscle coordination strategies in cycling.

    Science.gov (United States)

    Prilutsky, B I; Gregory, R J

    2000-09-01

    The functional significance of the stereotypical muscle activation patterns used in skilled multi-joint tasks is not well understood. Optimization methods could provide insight into the functional significance of muscle coordination. The purpose of this study was to predict muscle force patterns during cycling by pushing and pulling the pedal using different optimization criteria and compare the predictions with electromyographic (EMG) patterns. To address the purpose of the study, 1) the contribution of muscle length and velocity changes to EMG-muscle force relationships during cycling was examined by comparing joint moments calculated from EMG and inverse dynamics, 2) patterns of individual muscle forces during cycling of five subjects were predicted using 13 different optimization criteria, and 3) the properties of the criterion with the best performance in predicting the normalized EMG were used to explain the features and functional significance of muscle coordination in cycling. It was shown that the criterion that minimizes the sum of muscle stresses cubed demonstrated the best performance in predicting the relative magnitude and patterns of muscle activation. Based on this criterion, it was suggested that the functional significance of muscle coordination strategy in cycling may be minimization of fatigue and/or perceived effort.

  2. Spontaneous EMG activity for detection of arousal during general anaesthesia--comparison between recordings from frontal and neck musculature.

    Science.gov (United States)

    Tammisto, T; Toikka, O

    1991-03-01

    Monitoring of the spontaneous electromyographic activity of the frontal muscles (FEMG) is used for detection of impending arousal during general anaesthesia. Since the irritation caused by an endotracheal tube in situ might enhance the sensitivity of neck muscles in detecting arousal, EMG recordings from sternocleidomastoid muscles (NEMG) were compared to FEMG recordings under five different clinical conditions with 10 patients in each group. Two Anesthesia and Brain Activity Monitors (ABM, Datex Instrumentarium, Helsinki) were used simultaneously for recordings. NEMG was more sensitive than FEMG in detecting increases in EMG activity under all five conditions, although less distinct under conditions with a profound (90-100%) neuromuscular blockade. The results thus support our initial hypothesis and favour the use of neck muscles for monitoring. This, however, does not allow simultaneous recording of EEG through the same electrodes.

  3. Determination of Fatigue Following Maximal Loaded Treadmill Exercise by Using Wavelet Packet Transform Analysis and MLPNN from MMG-EMG Data Combinations.

    Science.gov (United States)

    Bilgin, Gürkan; Hindistan, I Ethem; Özkaya, Y Gül; Köklükaya, Etem; Polat, Övünç; Çolak, Ömer H

    2015-10-01

    The muscle fatigue can be expressed as decrease in maximal voluntary force generating capacity of the neuromuscular system as a result of peripheral changes at the level of the muscle, and also failure of the central nervous system to drive the motoneurons adequately. In this study, a muscle fatigue detection method based on frequency spectrum of electromyogram (EMG) and mechanomyogram (MMG) has been presented. The EMG and MMG data were obtained from 31 healthy, recreationally active men at the onset, and following exercise. All participants were performed a maximally exercise session in a motor-driven treadmill by using standard Bruce protocol which is the most widely used test to predict functional capacity. The method used in the present study consists of pre-processing, determination of the energy value based on wavelet packet transform, and classification phases. The results of the study demonstrated that changes in the MMG 176-234 Hz and EMG 254-313 Hz bands are critical to determine for muscle fatigue occurred following maximally exercise session. In conclusion, our study revealed that an algorithm with EMG and MMG combination based on frequency spectrum is more effective for the detection of muscle fatigue than EMG or MMG alone.

  4. Diagnostic validity of self-reported measures of sleep bruxism using an ambulatory single-channel EMG device.

    Science.gov (United States)

    Yachida, Wataru; Arima, Taro; Castrillon, Eduardo E; Baad-Hansen, Lene; Ohata, Noboru; Svensson, Peter

    2016-10-01

    Self-reported measures have been widely used to indicate the presence of possible and probable sleep bruxism (SB) in both research and clinical situations. However, few studies have attempted to assess the diagnostic validity of this approach. The aim of this study was to estimate the diagnostic validity of self-reported measures of SB using an ambulatory single-channel electromyographic (EMG) device. A total of 115 participants were enrolled and examined by standardized Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) including two questions related to SB: self-reported SB and morning-jaw symptoms. An ambulatory single-channel EMG device (GrindCare3™, Medotech A/S) was used for measuring jaw-muscle EMG activity during sleep for seven consecutive nights. Cut-off values for different measures of EMG activity (average, maximum and minimum) and the coefficient of variation (CV) were selected to divide participants into two groups, with higher or lower EMG activity or CV values. The sensitivity and specificity for each question and combination of them were calculated. Self-reported SB had the highest sensitivity (compared with morning-jaw symptoms) for all measures of EMG activity and CV, although the values were low to modest (average: 76.0%, maximum: 76.9%, minimum: 77.3%, CV: 61.0%). The specificity was low for both the questions related to the different measures of EMG activity and CV (35.1-52.4%). This study indicated that the diagnostic validity of self-reported measures of SB was low to modest using an ambulatory EMG device assessment as a reference. Using only self-reported measures for the assessment of SB may not have a high validity, which should be taken into consideration in the clinical evaluation of patients. Copyright © 2016 Japan Prosthodontic Society. Published by Elsevier Ltd. All rights reserved.

  5. Effects of Velocity on Electromyographic, Mechanomyographic, and Torque Responses to Repeated Eccentric Muscle Actions.

    Science.gov (United States)

    Hill, Ethan C; Housh, Terry J; Camic, Clayton L; Smith, Cory M; Cochrane, Kristen C; Jenkins, Nathaniel D M; Cramer, Joel T; Schmidt, Richard J; Johnson, Glen O

    2016-06-01

    The purposes of this study were to examine the effects of the velocity of repeated eccentric muscle actions on the torque and neuromuscular responses during maximal isometric and eccentric muscle actions. Twelve resistance-trained men performed 30 repeated, maximal, eccentric, isokinetic muscle actions at randomly ordered velocities of 60, 120, or 180°·s on separate days. Maximal voluntary isometric contractions (MVICs) were performed before (pretest) and after (posttest) the repeated eccentric muscle actions on each day. Eccentric isokinetic peak torque (EIPT) values were the averages of the first 3 and last 3 repetitions of the 30 repeated eccentric muscle actions. During the EIPT and MVIC muscle actions, electromyographic (EMG) and mechanomyographic (MMG) amplitude (EMG AMP and MMG AMP) and mean power frequency (EMG MPF and MMG MPF) values were assessed. These results indicated that the repeated eccentric muscle actions had no effects on EIPT, or the EMG AMP, EMG MPF, or MMG MPF values assessed during the EIPT muscle actions, but decreased MMG AMP. The repeated eccentric muscle actions, however, decreased MVIC torque, and also the EMG AMP and MMG MPF values assessed during the MVIC muscle actions, but increased MMG AMP. The results indicated that the velocity of the repeated eccentric muscle actions affected the MVIC torque responses, but not EIPT or any of the neuromuscular parameters. Furthermore, there are differences in the torque and neuromuscular responses for isometric vs. eccentric muscle actions after repeated eccentric muscle actions.

  6. Skeletal muscle ultrasound.

    Science.gov (United States)

    Pillen, Sigrid; van Alfen, Nens

    2011-12-01

    Muscle ultrasound is a convenient technique to visualize normal and pathological muscle tissue as it is non-invasive and real-time. Neuromuscular disorders give rise to structural muscle changes that can be visualized with ultrasound: atrophy can be objectified by measuring muscle thickness, while infiltration of fat and fibrous tissue increases muscle echo intensity, i.e. the muscles become whiter on the ultrasound image. Muscle echo intensity needs to be quantified to correct for age-related increase in echo intensity and differences between individual muscles. This can be done by gray scale analysis, a method that can be easily applied in daily clinical practice. Using this technique, it is possible to detect neuromuscular disorders with predictive values of 90%. Only in young children and metabolic myopathies the sensitivity is lower. Ultrasound is a dynamic technique and therefore capable of visualizing normal and pathological muscle movements. Fasciculations can easily be differentiated from other muscle movements. Ultrasound appeared to be even more sensitive in detecting fasciculations compared to Electromyography (EMG) and clinical observations, because it can visualize a large muscle area and deeper located muscles. With improving resolution and frame rate it has recently become clear that also smaller scale spontaneous muscle activity such as fibrillations can be detected by ultrasound. This opens the way to a broader use of muscle ultrasound in the diagnosis of peripheral nerve and muscle disorders.

  7. Skeletal muscle ultrasound

    Directory of Open Access Journals (Sweden)

    Sigrid Pillen

    2010-12-01

    Full Text Available Muscle ultrasound is a convenient technique to visualize normal and pathological muscle tissue as it is non-invasive and real-time. Neuromuscular disorders give rise to structural muscle changes that can be visualized with ultrasound: atrophy can be objectified by measuring muscle thickness, while infiltration of fat and fibrous tissue increase muscle echo intensity, i.e. the muscles become whiter on the ultrasound image. Muscle echo intensity need to be quantified to correct for age-related increase in echo intensity and differences between individual muscles. This can be done by gray scale analysis, a method that can be easily applied in daily clinical practice. Using this technique it is possible to detect neuromuscular disorders with predictive values of 90 percent. Only in young children and metabolic myopathies the sensitivity is lower. Ultrasound is a dynamic technique and therefore capable of visualizing normal and pathological muscle movements. Fasciculations can easily be differentiated from other muscle movements. Ultrasound appeared to be even more sensitive in detecting fasciculations compared to EMG and clinical observations, because it can visualize a large muscle area and deeper located muscles. With improving resolution and frame rate it has recently become clear that also smaller scale spontaneous muscle activity such as fibrillations can be detected by ultrasound. This opens the way to a broader use of muscle ultrasound in the diagnosis of peripheral nerve and muscle disorders.

  8. Measurement of lumbar multifidus muscle contraction with rehabilitative ultrasound imaging.

    Science.gov (United States)

    Kiesel, Kyle B; Uhl, Tim L; Underwood, Frank B; Rodd, Donald W; Nitz, Arthur J

    2007-05-01

    Rehabilitative Ultrasound Imaging (RUSI) has been validated as a noninvasive method to measure activation of selected muscles. The purpose of this study was to determine the relationship between muscle thickness change, as measured by ultrasonography, and electromyography (EMG) activity of the lumbar multifidus (LM) muscle in normal subjects. Bipolar fine wire electrodes were inserted into the LM at the L4 level of five subjects. Simultaneous EMG and RUSI data (muscle thickness) were collected while subjects performed increasingly demanding postural response tasks thought to activate the LM muscle. To determine the relationship between muscle thickness change and EMG activity, the normalized EMG data were correlated to normalized RUSI data. To determine if the tasks increased the demand on the LM, the mean EMG data were compared over each of the four tasks. Muscle thickness change as measured by RUSI was highly correlated with EMG activity of LM in asymptomatic subjects (r=.79,PRUSI is a valid and potentially useful method to measure activation of the LM muscle in a narrow range (19-34% of MVIC) in an asymptomatic population.

  9. Effective force control by muscle synergies

    Directory of Open Access Journals (Sweden)

    Denise J Berger

    2014-04-01

    Full Text Available Muscle synergies have been proposed as a way for the central nervous system (CNS to simplify the generation of motor commands and they have been shown to explain a large fraction of the variation in the muscle patterns across a variety of conditions. However, whether human subjects are able to control forces and movements effectively with a small set of synergies has not been tested directly. Here we show that muscle synergies can be used to generate target forces in multiple directions with the same accuracy achieved using individual muscles. We recorded electromyographic (EMG activity from 13 arm muscles and isometric hand forces during a force reaching task in a virtual environment. From these data we estimated the force associated to each muscle by linear regression and we identified muscle synergies by non-negative matrix factorization. We compared trajectories of a virtual mass displaced by the force estimated using the entire set of recorded EMGs to trajectories obtained using 4 to 5 muscle synergies. While trajectories were similar, when feedback was provided according to force estimated from recorded EMGs (EMG-control on average trajectories generated with the synergies were less accurate. However, when feedback was provided according to recorded force (force-control we did not find significant differences in initial angle error and endpoint error. We then tested whether synergies could be used as effectively as individual muscles to control cursor movement in the force reaching task by providing feedback according to force estimated from the projection of the recorded EMGs into synergy space (synergy-control. Human subjects were able to perform the task immediately after switching from force-control to EMG-control and synergy-control and we found no differences between initial movement direction errors and endpoint errors in all control modes. These results indicate that muscle synergies provide an effective strategy for motor

  10. Neural adaptations in isometric contractions with EMG and force biofeedback

    OpenAIRE

    Francisco Locks; Heleodório Honorato dos Santos; Luis Carlos Carvalho; Lígia Raquel Ortiz Gomes Stolt; José Jamacy de Almeida Ferreira

    2015-01-01

    This study aimed to evaluate the quadriceps femoris neural adaptations during isometric contractions using force and electromyogram (EMG) signals as visual biofeedback. Forty-two participants were randomly assigned to three groups: EMG group, tested with EMG biofeedback; Force group, tested with force biofeedback; and Control group, tested without biofeedback. Evaluations were performed pre (baseline) and post-tests to determine the maximum force and EMG amplitude during maximal voluntary iso...

  11. Ambient temperature and neck EMG with +Gz loading on a trampoline.

    Science.gov (United States)

    Sovelius, Roope; Oksa, Juha; Rintala, Harri; Huhtala, Heini; Siitonen, Simo

    2007-06-01

    Fighter pilots who are frequently exposed to severe cold ambient temperatures experience neck pain disabilities and occupational disorders more often than those who are not so exposed. We hypothesized that a cold-induced increase in muscle strain might lead to in-flight neck injuries. The aims of this study were to measure the level of cooling before takeoff and to determine muscle strain under Gz loading (0 to +4 Gz) at different temperatures. Test subjects' (n = 14) skin temperature (T(skin)) over the trapezoids was measured before the walk to the aircraft and again in the cockpit (air temperature -14 degrees C). The subjects then performed trampoline exercises in two different ambient temperatures (-2 degrees C and +21 degrees C) after a 30-min period at the respective temperatures. EMG activity of the sternocleidomastoid (SCM), cervical erector spinae (CES), trapezoid (TRA), thoracic erector spinae (TES) muscles, and Tskin of the SCM and TRA were measured. Tskin over the trapezoids decreased from 30.1 +/- 1.7 degrees C to 27.8 +/- 2.6 degrees C (p < 0.001) before takeoff. The change of muscle strain in cold was +11.0% in SCM, +14.9% in CES, +3.7% in TRA, and -1.7% in TES. Change was statistically significant in the cervical, uncovered area (SCM, CES). The linear regression model indicated a 2.6% increase in muscle strain per every decreased degree centigrade in skin temperature over the SCM. Superficial cooling over the neck muscles was significant prior to takeoff. Muscle loading in the cold caused higher EMG activity. A major increase in muscle strain was seen in the cervical muscles. These findings suggest a cold-induced increase in muscle strain during in-flight Gz loading.

  12. EMG, heart rate, and accelerometer as estimators of energy expenditure in locomotion.

    Science.gov (United States)

    Tikkanen, Olli; Kärkkäinen, Salme; Haakana, Piia; Kallinen, Mauri; Pullinen, Teemu; Finni, Taija

    2014-09-01

    Precise measures of energy expenditure (EE) during everyday activities are needed. This study assessed the validity of novel shorts measuring EMG and compared this method with HR and accelerometry (ACC) when estimating EE. Fifty-four volunteers (39.4 ± 13.9 yr) performed a maximal treadmill test (3-min loads) including walking with different speeds uphill, downhill, and on level ground and one running load. The data were categorized into all, low, and level loads. EE was measured by indirect calorimetry, whereas HR, ACC, and EMG were measured continuously. EMG from quadriceps (Q) and hamstrings (H) was measured using shorts with textile electrodes. Validity of the methods used to estimate EE was compared using Pearson correlations, regression coefficients, linear mixed models providing Akaike information criteria, and root mean squared error (RMSE) from cross-validation at the individual and population levels. At all loads, correlations with EE were as follows: EMG(QH), 0.94 ± 0.03; EMG(Q), 0.91 ± 0.03; EMG(H), 0.94 ± 0.03; HR, 0.96 ± 0.04; and ACC, 0.77 ± 0.10. The corresponding correlations at low loads were 0.89 ± 0.08, 0.79 ± 0.10, 0.93 ± 0.07, 0.89 ± 0.23, and 0.80 ± 0.07, and at level loads, they were 0.97 ± 0.03, 0.97 ± 0.05, 0.96 ± 0.04, 0.95 ± 0.08, and 0.99 ± 0.02, respectively. Akaike information criteria ranked the methods in accordance with the individual correlations. It is shown for the first time that EMG shorts can be used for EE estimations across a wide range of physical activity intensities in a heterogeneous group. Across all loads, HR is a superior method of predicting EE, whereas ACC is most accurate for level loads at the population level. At low levels of physical activity in changing terrains, thigh muscle EMG provides more accurate EE estimations than those in ACC and HR if individual calibrations are performed.

  13. Predicting 3D lip shapes using facial surface EMG

    NARCIS (Netherlands)

    Eskes, Merijn; van Alphen, Maarten J. A.; Balm, Alfons J. M.; Smeele, Ludi E.; Brandsma, Dieta; van der Heijden, Ferdinand

    2017-01-01

    Aim The aim of this study is to prove that facial surface electromyography (sEMG) conveys sufficient information to predict 3D lip shapes. High sEMG predictive accuracy implies we could train a neural control model for activation of biomechanical models by simultaneously recording sEMG signals and

  14. Detection of non-standard EMG profiles in walking

    NARCIS (Netherlands)

    Hof, A.L.; Elzinga, H.; Grimmius, W.; Halbertsma, J.P.

    The amplitude of an EMG and the temporal pattern can be used when considering if an EMG profile is normal or not. In the method described in this paper a gain factor of the complete EMG profile was determined and then the profile normalised with this gain factor. This normalised individual profile

  15. EMG Functional tasks recordings determines frailty phenotypes in males and females.

    Science.gov (United States)

    Jones, G R; Neubauer, N A; O'Connor, B; Jakobi, J M

    2016-05-01

    Identification of frailty is essential to understanding and mitigating age-related physical impairments. Previous studies have indicated that frailty phenotype can be identified through electromyography (EMG) when collected over the course of an 8-h day. However, long duration recordings challenge both the clinician and the older adults but activities of daily living that are most sensitive to changes in frailty status are currently unknown. The purpose of this study was to determine if muscle activity recorded during specific task, or groups of tasks, could be used to correctly classify middle-aged, non-frail, pre-frail, and frail older adult pheonotypes. Fifteen middle-aged (49 ± 5 years) and 76 older adults (77 ± 8 years) participated. Older adults were categorized as non-frail (n = 49), pre-frail (n = 20), or frail (n = 7) using self-selected normal gait speed and a modified frailty index score. Bursts and gaps in EMG of the biceps brachii, triceps brachii, vastus lateralis, and biceps femoris were measured bilaterally during nine different functional tasks. Relatively high levels of success for frailty group classification (near 90%) can be achieved from EMG. Bursts were more frequent and gaps fewer in frail compared with middle-aged and non-frail adults. The numbers of gaps and muscle quiescence in the upper limbs were particularly important. Changes in muscle activity offer predictive value in identifying frailty phenotype. Completing functional tasks (rising from the floor, toilet and chair) while undergoing EMG assessment can contribute to the identification of differences in frailty phenotype among older adults. Copyright © 2016 Elsevier Inc. All rights reserved.

  16. Muscle-derived Decellularised Extracellular Matrix Improves Functional Recovery in a Rat Latissimus Dorsi Muscle Defect Model

    Science.gov (United States)

    2013-12-01

    in vivo torque production from EMG in mouse muscles injured by eccentric contractions. J Physiol 1999;515(Pt 2):609e19. 27. Gamba PG, Conconi MT, Lo... Muscle -derived decellularised extracellular matrix improves functional recovery in a rat latissimus dorsi muscle defect model Xiaoyu K. Chen a,b...maxillary injuries; Muscle function; Skeletal muscle ; Volumetric muscle loss Summary Purpose: Craniofacial maxillary injuries represent nearly 30% of all

  17. A patient-specific EMG-driven neuromuscular model for the potential use of human-inspired gait rehabilitation robots.

    Science.gov (United States)

    Ma, Ye; Xie, Shengquan; Zhang, Yanxin

    2016-03-01

    A patient-specific electromyography (EMG)-driven neuromuscular model (PENm) is developed for the potential use of human-inspired gait rehabilitation robots. The PENm is modified based on the current EMG-driven models by decreasing the calculation time and ensuring good prediction accuracy. To ensure the calculation efficiency, the PENm is simplified into two EMG channels around one joint with minimal physiological parameters. In addition, a dynamic computation model is developed to achieve real-time calculation. To ensure the calculation accuracy, patient-specific muscle kinematics information, such as the musculotendon lengths and the muscle moment arms during the entire gait cycle, are employed based on the patient-specific musculoskeletal model. Moreover, an improved force-length-velocity relationship is implemented to generate accurate muscle forces. Gait analysis data including kinematics, ground reaction forces, and raw EMG signals from six adolescents at three different speeds were used to evaluate the PENm. The simulation results show that the PENm has the potential to predict accurate joint moment in real-time. The design of advanced human-robot interaction control strategies and human-inspired gait rehabilitation robots can benefit from the application of the human internal state provided by the PENm. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Mimicking muscle activity with electrical stimulation

    Science.gov (United States)

    Johnson, Lise A.; Fuglevand, Andrew J.

    2011-02-01

    Functional electrical stimulation is a rehabilitation technology that can restore some degree of motor function in individuals who have sustained a spinal cord injury or stroke. One way to identify the spatio-temporal patterns of muscle stimulation needed to elicit complex upper limb movements is to use electromyographic (EMG) activity recorded from able-bodied subjects as a template for electrical stimulation. However, this requires a transfer function to convert the recorded (or predicted) EMG signals into an appropriate pattern of electrical stimulation. Here we develop a generalized transfer function that maps EMG activity into a stimulation pattern that modulates muscle output by varying both the pulse frequency and the pulse amplitude. We show that the stimulation patterns produced by this transfer function mimic the active state measured by EMG insofar as they reproduce with good fidelity the complex patterns of joint torque and joint displacement.

  19. A comparison of EMG feedback and alternative anxiety treatment programs.

    Science.gov (United States)

    Hiebert, B A; Fitzsimmons, G

    1981-12-01

    Four cohorts of 40 subjects each were randomly assigned to 1 of 10 treatment conditions utilizing EMG feedback, cognitive monitoring training, systematic desensitization, high expectancy discussion group, or waiting list controls either in isolation or in various combinations. A three-way ANOVA for repeated measures indicated that significant anxiety reductions were experienced in all noncontrol treatment conditions. Treatment groups employing EMG feedback demonstrated significantly greater anxiety decrements on Cattell's IPAT Self-Analysis Form, and baseline frontalis EMG. Adding desensitization or cognitive monitoring to EMG feedback did not produce a more powerful effect than using EMG feedback alone. Sex and age differences were also observed. Some implications are discussed.

  20. Neck Muscle Fatigue with Helmet-Mounted Systems

    National Research Council Canada - National Science Library

    Eveland, Edward S; Pellettiere, Joseph A

    2006-01-01

    .... Changes in neck muscle strength were identified along with EMG evidence of fatigue. When flights occurred on an almost daily basis over 4 days, the force imparted to the neck was reduced each day...

  1. Neural adaptations in isometric contractions with EMG and force biofeedback

    Directory of Open Access Journals (Sweden)

    Francisco Locks

    2015-03-01

    Full Text Available This study aimed to evaluate the quadriceps femoris neural adaptations during isometric contractions using force and electromyogram (EMG signals as visual biofeedback. Forty-two participants were randomly assigned to three groups: EMG group, tested with EMG biofeedback; Force group, tested with force biofeedback; and Control group, tested without biofeedback. Evaluations were performed pre (baseline and post-tests to determine the maximum force and EMG amplitude during maximal voluntary isometric contraction (MVIC. The tests consisted of series of MVICs in which the participants were encouraged to surpass the force or EMG thresholds determined at baseline. The vastus lateralis EMG amplitude and knee extensor force increased significantly in all groups when compared the baseline and post-test evaluations values (p < .05. EMG percentage gain was significantly different between Force and Control groups (p < .01, while force percentage gain was not different between groups. Force biofeedback was more effective in producing neural adaptations.

  2. Electromyography (EMG) analysis on impact of classroom chair and table usage among primary school students in Perlis

    Science.gov (United States)

    Jing, Ewe Hui; Shan, Lim Shaiu; Effendi, M. S. M.; Rosli, Muhamad Farizuan

    2017-09-01

    The existing design of primary school classroom chair and table had brought low back pain, neck pain and shoulder pain problems respectively among students in primary school. The purpose of this study is to relate the electromyography (EMG) analysis with the most critical area of the body during sitting and writing. Six male and six female primary school students from SK Seri Perlis with no back pain, neck pain and shoulder pain problems involved were invited as respondents in this study. EMG experiment was carried out by first determined the critical point at T9 and L3 from thoracic and lumbar segment respectively for ECG electrode placement and performed with a series of sitting trials for analysis. The sitting trials performed were slouch to lumbopelvic sitting and slouch to thoracic sitting follow by instruction. Next, the electrode placement was identified at C2-C3 on cervical spine for neck and at midpoint between C7 to the lateral edge of acromion spanning for shoulder respectively. These points were identified for a series of writing task performing for the EMG analysis. There were two type of writing task which included writing by looking at the whiteboard and paper placed on the table. The subjects were instructed to rest during the experiment when necessary. During lumbopelvic sitting posture, the average muscle activation on lumbar area was at the highest peak. The peak indicated that there was critical effect from the experimental finding. The performance of writing task from whiteboard gave rise a higher impact on neck muscle while writing task from paper had a greater impact on shoulder muscle. The critical affected muscle on these areas was proven on these written tasks. The EMG experiment showed that the existing design of primary school classroom chair and table had brought impact on lumbar, neck and shoulder towards the students who were using. A future recommendation suggests that to redesign primary school classroom chair and table which

  3. Macro-EMG and MUNE changes in patients with amyotrophic lateral sclerosis: one-year follow up.

    Science.gov (United States)

    Sartucci, Ferdinando; Moscato, Gianluca; Rossi, Chiara; Caleo, Matteo; Bocci, Tommaso; Murri, Luigi; Giannini, Fabio; Rossi, Alessandro

    2011-05-01

    We assessed changes in Motor Units (MU) and extent of MU loss using macro-electromyography (macro-EMG) and Motor Unit Number Estimation (MUNE). We applied these techniques to a sample of 61 Amyotrophic Lateral Sclerosis (ALS) patients basally (T0) and after 4 (T1), 8 (T2), and 12 (T3) months. Macro Motor Unit Potentials (macro-MUPs) were derived from Biceps Brachii (BB) muscle; MUNE was performed both in BB and Abductor Digiti Minimi (ADM) muscles of the same side. Macro-MUPs area resulted in progressive increase at T1, T2, and T3 with respect to T0. Fiber density (FD) at T3 decreases a bit than at T2. Functioning MUS number decreased in both the muscles throughout the entire follow-up with respect to T0 and the rate of MU decrease was similar in both the muscles, but steeper distally. Macro-EMG increase and FD decrease suggest that a process of MU rearrangement begins to fall after 8 months of disease course. Combined use of macro-EMG and MUNE techniques in ALS patients allows to track over time changes in muscle MU features and number in face of progressive anterior horn cells death during disease's evolution.

  4. Stimulation map for control of functional grasp based on multi-channel EMG recordings.

    Science.gov (United States)

    Popović Maneski, Lana; Topalović, Ivan; Jovičić, Nenad; Dedijer, Suzana; Konstantinović, Ljubica; Popović, Dejan B

    2016-11-01

    Transcutaneous activation of muscles with electrical stimulation has limited selectivity in recruiting paralyzed muscles in stroke patients. However, the selectivity could be increased by the application of smaller electrodes and their appropriate positioning on the skin. We developed a method for selecting the appropriate positions of the stimulating electrodes based on electromyography (EMG). The EMG activity maps were estimated from signals recorded with two electrode arrays and two 24-channel wearable amplifiers positioned on the nonparetic and paretic forearms. The areas where the difference between the EMG maps obtained from the nonparetic and paretic arms was significant were identified as the stimulation sites. The stimulation was applied through array electrodes with magnetic holders and two wearable stimulators with four output channels each. The measures of functionality included joint angles measured with goniometers (hand opening) and grasp force measured with a multi-contact dynamometer (grasping). The stimulation protocol comprised co-activation of flexors and extensors to stabilize the wrist joint and prevent pronation/supination. Copyright © 2016 IPEM. Published by Elsevier Ltd. All rights reserved.

  5. Development of new protocols and analysis procedures for the assessment of LBP by surface EMG techniques.

    Science.gov (United States)

    Oddsson, L I; Giphart, J E; Buijs, R J; Roy, S H; Taylor, H P; De Luca, C J

    1997-10-01

    Spectral parameters of the surface electromyographic (EMG) signal from lumbar back muscles assessed during a fatiguing isometric contraction can be used to classify different categories of low back pain (LBP) subjects and control subjects without LBP. In the test protocol currently used at the NeuroMuscular Research Center at Boston University, subjects contract their back muscles at 80% of their maximal voluntary contraction (MVC) force. This fatigue-based protocol has been successfully applied to persons with subacute or chronic LBP; those in acute pain, however, have not been included because of their inability to perform a maximal exertion. In this paper we will examine the force sensitivity of the currently used EMG parameters and also give an overview of some of our efforts to develop new test procedures. Our goal is to develop force-insensitive surface EMG parameters that can be used for classification purposes in populations of subjects who develop low trunk extension forces. In addition, the development of a model to predict MVC from anthropometrical measurements will be presented.

  6. Gender differences in time-frequency EMG analysis of unanticipated cutting maneuvers.

    Science.gov (United States)

    Beaulieu, Mélanie L; Lamontagne, Mario; Xu, Lanyi

    2008-10-01

    The purpose of this study is to compare the time-frequency characteristic, using nonlinearly scaled wavelets, of the EMG signal as well as the three-dimensional (3D) knee kinematics of female and male elite soccer players performing an unanticipated cutting maneuver. Fifteen female and 15 male elite soccer players performed several cutting maneuvers during which EMG of eight muscles of the leg and 3D kinematics of the knee were recorded. To create an unanticipated condition, the participants executed one of three tasks, which were signaled to them with an illuminated target board. Male participants generally executed the unanticipated cutting maneuver with a quadriceps activation of higher frequency components. These gender differences were also found at initial ground contact (IC) for the vastii and biceps femoris (BF) muscles. These higher frequencies dominated the signal earlier in time for the BF and later for the tibialis anterior (TA) in women. Furthermore, women performed the cutting task with greater knee abduction than did the men. Female athletes adopted a different motor unit recruitment strategy that was particularly evident at, and near, IC resulting in lower frequency components in the EMG signal of the lateral hamstring. This strategy may play a role in explaining the gender bias in anterior cruciate ligament (ACL) injury rates. Gender differences in knee kinematics were also observed, exposing the female ACL to higher strain, which may be the result of differences in neuromuscular strategies to stabilize the knee joint.

  7. Estimation of elbow-induced wrist force with EMG signals using fast orthogonal search.

    Science.gov (United States)

    Mobasser, Farid; Eklund, J Mikael; Hashtrudi-Zaad, Keyvan

    2007-04-01

    In many studies and applications that include direct human involvement-such as human-robot interaction, control of prosthetic arms, and human factor studies-hand force is needed for monitoring or control purposes. The use of inexpensive and easily portable active electromyogram (EMG) electrodes and position sensors would be advantageous in these applications compared to the use of force sensors, which are often very expensive and require bulky frames. Multilayer perceptron artificial neural networks (MLPANN) have been used commonly in the literature to model the relationship between surface EMG signals and muscle or limb forces for different anatomies. This paper investigates the use of fast orthogonal search (FOS), a time-domain method for rapid nonlinear system identification, for elbow-induced wrist force estimation. It further compares the forces estimated using FOS with the forces estimated by MLPANN for the same human anatomy under an ensemble of operational conditions. In this paper, the EMG signal readings from upper arm muscles involved in elbow joint movement and sensed elbow angular position and velocity are utilized as inputs. A single degree-of-freedom robotic experimental testbed has been constructed and used for data collection, training and validation.

  8. Textile Electrodes Embedded in Clothing: A Practical Alternative to Traditional Surface Electromyography when Assessing Muscle Excitation during Functional Movements

    Directory of Open Access Journals (Sweden)

    Steffi L. Colyer, Polly M. McGuigan

    2018-03-01

    Full Text Available Textile electromyography (EMG electrodes embedded in clothing allow muscle excitation to be recorded in previously inaccessible settings; however, their ability to accurately and reliably measure EMG during dynamic tasks remains largely unexplored. To quantify the validity and reliability of textile electrodes, 16 recreationally active males completed two identical testing sessions, within which three functional movements (run, cycle and squat were performed twice: once wearing EMG shorts (measuring quadriceps, hamstrings and gluteals myoelectric activity and once with surface EMG electrodes attached to the vastus lateralis, biceps femoris and gluteus maximus. EMG signals were identically processed to provide average rectified EMG (normalized to walking and excitation length. Results were compared across measurement systems and demonstrated good agreement between the magnitude of muscle excitation when EMG activity was lower, but agreement was poorer when excitation was higher. The length of excitation bursts was consistently longer when measured using textile vs. surface EMG electrodes. Comparable between-session (day-to-day repeatability was found for average rectified EMG (mean coefficient of variation, CV: 42.6 and 41.2% and excitation length (CV: 12.9 and 9.8% when using textile and surface EMG, respectively. Additionally, similar within-session repeatability (CV was recorded for average rectified EMG (13.8 and 14.1% and excitation length (13.0 and 12.7% for textile and surface electrodes, respectively. Generally, textile EMG electrodes appear to be capable of providing comparable muscle excitation information and reproducibility to surface EMG during dynamic tasks. Textile EMG shorts could therefore be a practical alternative to traditional laboratory-based methods allowing muscle excitation information to be collected in more externally-valid training environments.

  9. Effect of whole-body vibration on lower-limb EMG activity in subjects with and without spinal cord injury

    Science.gov (United States)

    Alizadeh-Meghrazi, Milad; Masani, Kei; Zariffa, José; Sayenko, Dimitry G.; Popovic, Milos R.; Craven, B. Catharine

    2014-01-01

    Objective Traumatic spinal cord injury (SCI) results in substantial reductions in lower extremity muscle mass and bone mineral density below the level of the lesion. Whole-body vibration (WBV) has been proposed as a means of counteracting or treating musculoskeletal degradation after chronic motor complete SCI. To ascertain how WBV might be used to augment muscle and bone mass, we investigated whether WBV could evoke lower extremity electromyography (EMG) activity in able-bodied individuals and individuals with SCI, and which vibration parameters produced the largest magnitude of effect. Methods Ten male subjects participated in the study, six able-bodied and four with chronic SCI. Two different manufacturers' vibration platforms (WAVE® and Juvent™) were evaluated. The effects of vibration amplitude (0.2, 0.6 or 1.2 mm), vibration frequency (25, 35, or 45 Hz), and subject posture (knee angle of 140°, 160°, or 180°) on lower extremity EMG activation were determined (not all combinations of parameters were possible on both platforms). A novel signal processing technique was proposed to estimate the power of the EMG waveform while minimizing interference and artifacts from the plate vibration. Results WBV can elicit EMG activity among subjects with chronic SCI, if appropriate vibration parameters are employed. The amplitude of vibration had the greatest influence on EMG activation, while the frequency of vibration had lesser but statistically significant impact on the measured lower extremity EMG activity. Conclusion These findings suggest that WBV with appropriate parameters may constitute a promising intervention to treat musculoskeletal degradation after chronic SCI. PMID:24986541

  10. Electrically and Hybrid-Induced Muscle Activations: Effects of Muscle Size and Fiber Type.

    Science.gov (United States)

    Stratton, Kelly; Faghri, Pouran D

    2016-06-13

    The effect of three electrical stimulation (ES) frequencies (10, 35, and 50 Hz) on two muscle groups with different proportions of fast and slow twitch fibers (abductor pollicis brevis (APB) and vastus lateralis (VL)) was explored. We evaluated the acute muscles' responses individually and during hybrid activations (ES superimposed by voluntary activations). Surface electromyography (sEMG) and force measurements were evaluated as outcomes. Ten healthy adults (mean age: 24.4 ± 2.5 years) participated after signing an informed consent form approved by the university Institutional Review Board. Protocols were developed to: 1) compare EMG activities during each frequency for each muscle when generating 25% Maximum Voluntary Contraction (MVC) force, and 2) compare EMG activities during each frequency when additional voluntary activation was superimposed over ES-induced 25% MVC to reach 50% and 75% MVC. Empirical mode decomposition (EMD) was utilized to separate ES artifacts from voluntary muscle activation. For both muscles, higher stimulation frequency (35 and 50Hz) induced higher electrical output detected at 25% of MVC, suggesting more recruitment with higher frequencies. Hybrid activation generated proportionally less electrical activity than ES alone. ES and voluntary activations appear to generate two different modes of muscle recruitment. ES may provoke muscle strength by activating more fatiguing fast acting fibers, but voluntary activation elicits more muscle coordination. Therefore, during the hybrid activation, less electrical activity may be detected due to recruitment of more fatigue-resistant deeper muscle fibers, not reachable by surface EMG.

  11. Muscle activity and inactivity periods during normal daily life.

    Directory of Open Access Journals (Sweden)

    Olli Tikkanen

    Full Text Available Recent findings suggest that not only the lack of physical activity, but also prolonged times of sedentary behaviour where major locomotor muscles are inactive, significantly increase the risk of chronic diseases. The purpose of this study was to provide details of quadriceps and hamstring muscle inactivity and activity during normal daily life of ordinary people. Eighty-four volunteers (44 females, 40 males, 44.1±17.3 years, 172.3±6.1 cm, 70.1±10.2 kg were measured during normal daily life using shorts measuring muscle electromyographic (EMG activity (recording time 11.3±2.0 hours. EMG was normalized to isometric MVC (EMG(MVC during knee flexion and extension, and inactivity threshold of each muscle group was defined as 90% of EMG activity during standing (2.5±1.7% of EMG(MVC. During normal daily life the average EMG amplitude was 4.0±2.6% and average activity burst amplitude was 5.8±3.4% of EMG(MVC (mean duration of 1.4±1.4 s which is below the EMG level required for walking (5 km/h corresponding to EMG level of about 10% of EMG(MVC. Using the proposed individual inactivity threshold, thigh muscles were inactive 67.5±11.9% of the total recording time and the longest inactivity periods lasted for 13.9±7.3 min (2.5-38.3 min. Women had more activity bursts and spent more time at intensities above 40% EMG(MVC than men (p<0.05. In conclusion, during normal daily life the locomotor muscles are inactive about 7.5 hours, and only a small fraction of muscle's maximal voluntary activation capacity is used averaging only 4% of the maximal recruitment of the thigh muscles. Some daily non-exercise activities such as stair climbing produce much higher muscle activity levels than brisk walking, and replacing sitting by standing can considerably increase cumulative daily muscle activity.

  12. EMG signals characterization in three states of contraction by fuzzy network and feature extraction

    CERN Document Server

    Mokhlesabadifarahani, Bita

    2015-01-01

    Neuro-muscular and musculoskeletal disorders and injuries highly affect the life style and the motion abilities of an individual. This brief highlights a systematic method for detection of the level of muscle power declining in musculoskeletal and Neuro-muscular disorders. The neuro-fuzzy system is trained with 70 percent of the recorded Electromyography (EMG) cut off window and then used for classification and modeling purposes. The neuro-fuzzy classifier is validated in comparison to some other well-known classifiers in classification of the recorded EMG signals with the three states of contractions corresponding to the extracted features. Different structures of the neuro-fuzzy classifier are also comparatively analyzed to find the optimum structure of the classifier used.

  13. Application of wireless inertial measurement units and EMG sensors for studying deglutition - Preliminary results.

    Science.gov (United States)

    Imtiaz, U; Yamamura, K; Kong, W; Sessa, S; Lin, Z; Bartolomeo, L; Ishii, H; Zecca, M; Yamada, Y; Takanishi, A

    2014-01-01

    Different types of sensors are being used to study deglutition and mastication. These often suffer from problems related to portability, cost, reliability, comfort etc. that make it difficult to use for long term studies. An inertial measurement based sensor seems a good fit in this application; however its use has not been explored much for the specific application of deglutition research. In this paper, we present a system comprised of an IMU and EMG sensor that are integrated together as a single system. With a preliminary experiment, we determine that the system can be used for measuring the head-neck posture during swallowing in addition to other parameters during the swallowing phase. The EMG sensor may not always be a reliable source of physiological data especially for small clustered muscles like the ones responsible for swallowing. In this case, we explore the possibility of using gyroscopic data for the recognition of deglutition events.

  14. High-density EMG E-textile systems for the control of active prostheses.

    Science.gov (United States)

    Farina, Dario; Lorrain, Thomas; Negro, Francesco; Jiang, Ning

    2010-01-01

    Myoelectric control of active prostheses requires electrode systems that are easy to apply for daily repositioning of the electrodes by the user. In this study we propose the use of Smart Fabric and Interactive Textile (SFIT) systems as an alternative solution for recording high-density EMG signals for myoelectric control. A sleeve covering the upper and lower arm, which contains 100 electrodes arranged in four grids of 5 × 5 electrodes, was used to record EMG signals in 3 subjects during the execution of 9 tasks of the wrist and hand. The signals were analyzed by extracting wavelet coefficients which were classified with linear discriminant analysis. The average classification accuracy for the nine tasks was 89.1 ± 1.9 %. These results show that SFIT systems can be used as an effective way for muscle-machine interfacing.

  15. Acquisition and Analysis of EMG Signals to Recognize Multiple Hand Movements for Prosthetic Applications

    Directory of Open Access Journals (Sweden)

    Giuseppina Gini

    2012-01-01

    Full Text Available One of the main problems in developing active prosthesis is how to control them in a natural way. In order to increase the effectiveness of hand prostheses there is a need in better exploiting electromyography (EMG signals. After an analysis of the movements necessary for grasping, we individuated five movements for the wrist-hand mobility. Then we designed the basic electronics and software for the acquisition and the analysis of the EMG signals. We built a small size electronic device capable of registering them that can be integrated into a hand prosthesis. Among all the numerous muscles that move the fingers, we have chosen the ones in the forearm and positioned only two electrodes. To recognize the operation, we developed a classification system, using a novel integration of Artificial Neural Networks (ANN and wavelet features.

  16. Differential EMG biofeedback for children with ADHD: a control method for neurofeedback training with a case illustration.

    Science.gov (United States)

    Maurizio, S; Liechti, M D; Brandeis, D; Jäncke, L; Drechsler, R

    2013-06-01

    The objective of the present paper was to develop a differential electromyographic biofeedback (EMG-BF) training for children with attention-deficit/hyperactivity disorder (ADHD) matching multiple neurofeedback training protocols in order to serve as a valid control training. This differential EMG-BF training method feeds back activity from arm muscles involved in fine motor skills such as writing and grip force control. Tonic EMG-BF training (activation and deactivation blocks, involving bimanual motor tasks) matches the training of EEG frequency bands, while phasic EMG-BF training (short activation and deactivation trials) was developed as an equivalent to the training of slow cortical potentials. A case description of a child who learned to improve motor regulation in most task conditions and showed a clinically relevant reduction of behavioral ADHD symptoms illustrates the training course and outcome. Differential EMG-BF training is feasible and provides well-matched control conditions for neurofeedback training in ADHD research. Future studies should investigate its value as a specific intervention for children diagnosed with ADHD and comorbid sensorimotor problems.

  17. Reliability of Triggered EMG for Prediction of Safety during Pedicle Screw Placement in Adolescent Idiopathic Scoliosis Surgery

    Science.gov (United States)

    Lee, Hyun-Joo; Jeong, Won-Ju; Oh, Chang-Wug; Bae, Jae-Sung; Cho, Hwan-Seong; Jeon, In-Ho; Cho, Chang-Hyun; Park, Byung-Chul

    2011-01-01

    Study Design We performed a prospective study to evaluate the reliability of using triggered electromyography (EMG) for predicting pedicle wall breakthrough during the placement of pedicle screw in adolescent idiopathic scoliosis surgery. Purpose We wanted to correlate pedicle wall breakthrough with the triggered EMG threshold of stimulation and the postoperative computed tomography (CT) findings. Overview of Literature Pedicle wall breakthrough has been reported to be difficult to evaluate by radiographs. Triggered EMG had been found to be a more sensitive test to detect this breakthrough. Methods Seven patients who underwent the insertion of 103 pedicle screws were evaluated. The triggered EMG activity was recorded from several muscles depending on the level of screw placement. The postoperative CT scans were read by a spine surgeon who was a senior fellow in orthopedics, and a musculoskeletal radiologist. Results The mean age at surgery was 12.6 years (range, 11 to 17 years). The preoperative mean Cobb angle was 54.7° (range, 45 to 65°). There were 80 thoracic screws and 23 lumbar screws. All the screws had stimulation thresholds of ≥ 6 mA, except 3 screws with the stimulation threshold of EMG helps to assess the pedicle screw placement. Pedicle screws that had stimulation threshold of ≥ 6 mA were safe, with 90.3% reliability, as was assessed on the postoperative CT scans. PMID:21386946

  18. Transradial Amputee Gesture Classification Using an Optimal Number of sEMG Sensors: An Approach Using ICA Clustering.

    Science.gov (United States)

    Naik, Ganesh R; Al-Timemy, Ali H; Nguyen, Hung T

    2016-08-01

    Surface electromyography (sEMG)-based pattern recognition studies have been widely used to improve the classification accuracy of upper limb gestures. Information extracted from multiple sensors of the sEMG recording sites can be used as inputs to control powered upper limb prostheses. However, usage of multiple EMG sensors on the prosthetic hand is not practical and makes it difficult for amputees due to electrode shift/movement, and often amputees feel discomfort in wearing sEMG sensor array. Instead, using fewer numbers of sensors would greatly improve the controllability of prosthetic devices and it would add dexterity and flexibility in their operation. In this paper, we propose a novel myoelectric control technique for identification of various gestures using the minimum number of sensors based on independent component analysis (ICA) and Icasso clustering. The proposed method is a model-based approach where a combination of source separation and Icasso clustering was utilized to improve the classification performance of independent finger movements for transradial amputee subjects. Two sEMG sensor combinations were investigated based on the muscle morphology and Icasso clustering and compared to Sequential Forward Selection (SFS) and greedy search algorithm. The performance of the proposed method has been validated with five transradial amputees, which reports a higher classification accuracy ( > 95%). The outcome of this study encourages possible extension of the proposed approach to real time prosthetic applications.

  19. The effects of amplitude normalization and EMG targets on cVEMP interaural amplitude asymmetry.

    Science.gov (United States)

    McCaslin, Devin L; Jacobson, Gary P; Hatton, Kelsey; Fowler, Andrea P; DeLong, Andrew P

    2013-01-01

    The purpose of this investigation was to determine whether the use of visual feedback of tonic electromyographic (EMG) activity, or the use of amplitude normalization techniques would reduce significantly the variability in cervical vestibular evoked myogenic potential (cVEMP) P13-N23 interaural amplitude asymmetry data in otologically and neurologically intact children and adults. There were 97 subjects, both pediatric and adult, from whom the authors recorded cVEMPs with and without the use of an EMG target and amplitude normalization techniques. The four conditions were: (1) conventional recording (condition 1), (2) conventional recording with an EMG target (condition 2), (3) same as condition 1, with the addition of postacquisition amplitude normalization techniques, and (4) same as condition 2, with the addition of postacquisition amplitude normalization techniques. The absolute peak to peak amplitude of positive-negative response (P13-N23), absolute latency of P13, and the left or right amplitude asymmetry of P13-N23 were measured. Neither P13-N23 amplitudes nor latencies, neither mean root mean square (RMS) of the full wave rectified EMG activity, nor the standard deviation of the RMS EMG activity differed significantly when subjects were, and were not, asked to ensure their tonic EMG activity exceeded a visual target (i.e., representing >50 µV RMS EMG). Amplitude normalization of the cVEMP waveforms failed to reduce significantly the variability in the amplitude asymmetry data. Activating the sternocleidomastoid muscle with the patient in a semirecumbent position, with head turned away from the stimulated ear and head elevated (i.e., an optimal activation technique) was sufficient to produce the highest amplitude cVEMPs with an acceptable amount of variability in subjects of all ages. Group data suggested that the use of visual targets and amplitude normalization routines did not reduce significantly the variability in cVEMP interaural amplitude asymmetry

  20. Feature extraction of the first difference of EMG time series for EMG pattern recognition.

    Science.gov (United States)

    Phinyomark, Angkoon; Quaine, Franck; Charbonnier, Sylvie; Serviere, Christine; Tarpin-Bernard, Franck; Laurillau, Yann

    2014-11-01

    This paper demonstrates the utility of a differencing technique to transform surface EMG signals measured during both static and dynamic contractions such that they become more stationary. The technique was evaluated by three stationarity tests consisting of the variation of two statistical properties, i.e., mean and standard deviation, and the reverse arrangements test. As a result of the proposed technique, the first difference of EMG time series became more stationary compared to the original measured signal. Based on this finding, the performance of time-domain features extracted from raw and transformed EMG was investigated via an EMG classification problem (i.e., eight dynamic motions and four EMG channels) on data from 18 subjects. The results show that the classification accuracies of all features extracted from the transformed signals were higher than features extracted from the original signals for six different classifiers including quadratic discriminant analysis. On average, the proposed differencing technique improved classification accuracies by 2-8%. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  1. Electromyographic biofeedback training for reducing muscle pain and tension on masseter and temporal muscles: A pilot study.

    Science.gov (United States)

    Criado, Laura; de La Fuente, Antonio; Heredia, Margarita; Montero, Javier; Albaladejo, Alberto; Criado, José-María

    2016-12-01

    Due to the absence of agreement about an effective unified treatment for temporomandibular disorders, non-invasive therapies such as EMG-biofeedback generate a greater interest. Furthermore, most studies to the present show methodological deficiencies that must be solved in the future, which makes important to emphasize this line of studies. Fourteen patients were selected for this case series study, and replied to a questionnaire concerning awareness of bruxism, painful muscles, and muscle tension. They also practiced an intraoral exploration (occlusal analysis and mandibular dynamics), and an extraoral exploration of the head and neck muscles and the temporomandibular joint. Before each session, patients responded to a questionnaire about the subjective perceived improvement. In each session, a period of three minutes of pre-biofeedback EMG activity of right masseter and temporal muscles was registered, then patients performed 30 iterations of visual EMG-biofeedback training and finally, a period of three minutes of post-EMG activity was also registered for those muscles. Patients performed four sessions. A decrease in painful symptoms was found for all patients since the first session. EMG activity decreases (pmuscles during the biofeedback training stage, in the four sessions. It is also observed a decrease (pmuscle at the post-biofeedback stage, in the second and third sessions. There is likewise a decrease in EMG post-biofeedback activity of the temporal muscle (pmuscles during the session. This decrease persists during the post-biofeedback period since the second session. Also there is a decrease in painful symptoms for all patients. Key words:Muscle tension, muscle pain, EMG-biofeedback, masseter muscle, temporal muscle.

  2. The number and choice of muscles impact the results of muscle synergy analyses

    Directory of Open Access Journals (Sweden)

    Katherine Muterspaugh Steele

    2013-08-01

    Full Text Available One theory for how humans control movement is that muscles are activated in weighted groups or synergies. Studies have shown that electromyography (EMG from a variety of tasks can be described by a low-dimensional space thought to reflect synergies. These studies use algorithms, such as nonnegative matrix factorization, to identify synergies from EMG. Due to experimental constraints, EMG can rarely be taken from all muscles involved in a task. However, it is unclear if the choice of muscles included in the analysis impacts estimated synergies. The aim of our study was to evaluate the impact of the number and choice of muscles on synergy analyses. We used a musculoskeletal model to calculate muscle activations required to perform an isometric upper-extremity task. Synergies calculated from the activations from the musculoskeletal model were similar to a prior experimental study. To evaluate the impact of the number of muscles included in the analysis, we randomly selected subsets of between 5 and 29 muscles and compared the similarity of the synergies calculated from each subset to a master set of synergies calculated from all muscles. We determined that the structure of synergies is dependent upon the number and choice of muscles included in the analysis. When five muscles were included in the analysis, the similarity of the synergies to the master set was only 0.57 ± 0.54; however, the similarity improved to over 0.8 with more than ten muscles. We identified two methods, selecting dominant muscles from the master set or selecting muscles with the largest maximum isometric force, which significantly improved similarity to the master set and can help guide future experimental design. Analyses that included a small subset of muscles also over-estimated the variance accounted for (VAF by the synergies compared to an analysis with all muscles. Thus, researchers should use caution using VAF to evaluate synergies when EMG is measured from a small

  3. EMG-Torque correction on Human Upper extremity using Evolutionary Computation

    Science.gov (United States)

    JL, Veronica; Parasuraman, S.; Khan, M. K. A. Ahamed; Jeba DSingh, Kingsly

    2016-09-01

    There have been many studies indicating that control system of rehabilitative robot plays an important role in determining the outcome of the therapy process. Existing works have done the prediction of feedback signal in the controller based on the kinematics parameters and EMG readings of upper limb's skeletal system. Kinematics and kinetics based control signal system is developed by reading the output of the sensors such as position sensor, orientation sensor and F/T (Force/Torque) sensor and there readings are to be compared with the preceding measurement to decide on the amount of assistive force. There are also other works that incorporated the kinematics parameters to calculate the kinetics parameters via formulation and pre-defined assumptions. Nevertheless, these types of control signals analyze the movement of the upper limb only based on the movement of the upper joints. They do not anticipate the possibility of muscle plasticity. The focus of the paper is to make use of the kinematics parameters and EMG readings of skeletal system to predict the individual torque of upper extremity's joints. The surface EMG signals are fed into different mathematical models so that these data can be trained through Genetic Algorithm (GA) to find the best correlation between EMG signals and torques acting on the upper limb's joints. The estimated torque attained from the mathematical models is called simulated output. The simulated output will then be compared with the actual individual joint which is calculated based on the real time kinematics parameters of the upper movement of the skeleton when the muscle cells are activated. The findings from this contribution are extended into the development of the active control signal based controller for rehabilitation robot.

  4. Assessment of Diaphragm and External Intercostals Fatigue from Surface EMG using Cervical Magnetic Stimulation

    Directory of Open Access Journals (Sweden)

    Ya-Ju Chang

    2008-03-01

    Full Text Available This study was designed: (1 to test the reliability of surface electromyography (sEMG recording of the diaphragm and external intercostals contractions response to cervical magnetic stimulation (CMS, (2 to examine the amount and the types of inspiratory muscle fatigue that developed after maximum voluntary ventilation (MVV maneuvers.Ten male college students without physical disability (22.1±2.0 years old participated in the study and each completed a control (quiet breathing trial and a fatigue (MVV maneuvers trial sequentially. In the quiet breathing trial, the subjects maintained quiet breathing for five minutes. The subjects performed five maximal static inspiratory efforts and received five CMS before and after the quiet breathing. In the MVV trial, subjects performed five maximal inspiratory efforts and received five CMS before, immediately after, and ten minutes after two sets of MVV maneuvers performed five minutes apart. Maximal inspiratory pressure (PImax, sEMG of diaphragm and external intercostals during maximal static inspiratory efforts and during CMS were recorded. In the quiet breathing trial, high intraclass correlation coefficients (ICC=0.95-0.99 were observed in all the variables. In the MVV trial, the PImax, the EMG amplitude and the median power frequency during maximal static inspiratory efforts significantly decreased in both the diaphragm and the external intercostals immediately after the MVV maneuvers Sensors 2008, 8 2175 (P 0.05. It is concluded that the sEMG recordings of the diaphragm during maximal static inspiratory efforts and in response to CMS allow reproducible sequential assessment of diaphragm contractility. MVV maneuvers resulted in inspiratory muscles fatigue, possibly central fatigue.

  5. Noise-assisted multivariate empirical mode decomposition for multichannel EMG signals.

    Science.gov (United States)

    Zhang, Yi; Xu, Peng; Li, Peiyang; Duan, Keyi; Wen, Yuexin; Yang, Qin; Zhang, Tao; Yao, Dezhong

    2017-08-23

    Ensemble Empirical Mode Decomposition (EEMD) has been popularised for single-channel Electromyography (EMG) signal processing as it can effectively extract the temporal information of the EMG time series. However, few papers examine the temporal and spatial characteristics across multiple muscle groups in relation to multichannel EMG signals. The experimental data was obtained from the Center for Machine Learning and Intelligent Systems, University of California Irvine (UCI). The data was donated by the Nueva Granada Military University and the Technopark node Manizales in Colombia. The databases of 11 male subjects from the healthy group were taken into the study. The subjects undergo three exercise programs, leg extension from a sitting position (sitting), flexion of the leg up (standing), and gait (walking), while four electrodes were placed on biceps femoris (BF), vastus medialis (VM), rectus femoris (RF), and semitendinosus (ST). Based on the experimental data, a comparative study is provided by assessing the Empirical Mode Decomposition (EMD)-based approaches, EEMD, Multivariate EMD (MEMD), and Noise-Assisted MEMD (NA-MEMD). The outcomes from these approaches are then quantitatively estimated on the basis of three criterions, the number of Intrinsic Mode Functions (IMFs), mode-alignment and mode-mixing. Both MEMD and NA-MEMD methods (except EEMD) can guarantee equal numbers of IMFs. For mode-alignment and mode-mixing, NA-MEMD is optimal compared with MEMD and EEMD, and MEMD is merely better than EEMD. This study proposes the NA-MEMD approach for multichannel EMG signal processing. This finding implies that NA-MEMD is effective for simultaneously analysing IMFs based frequency bands. It has a vital clinical implication in exploring the neuromuscular patterns that enable the multiple muscle groups to coordinate while performing the functional activities of daily living.

  6. Quantification of surface EMG signals to monitor the effect of a Botox treatment in six healthy ponies and two horses with stringhalt: preliminary study.

    Science.gov (United States)

    Wijnberg, I D; Schrama, S E A; Elgersma, A E; Maree, J T M; de Cocq, P; Back, W

    2009-03-01

    Therapeutic options for stringhalt in horses are limited, whereas medical experiences with botulinum toxin type A (Botox) have been positive. To evaluate its effectiveness in horses, surface electromyography (sEMG) signals before and after injection need to be quantified. Treatment of healthy ponies and cases with Botox should reduce muscle activity in injected muscles and reduce spastic movements without adverse side effects. Unilaterally, the extensor digitorum longus, extensor digitorum lateralis and lateral vastus muscles of 6 healthy mature Shetland ponies and 2 talented Dutch Warmblood dressage horses with stringhalt were injected (maximum of 400 iu per pony and 700 iu per case; 100 iu in 5 ml NaCl divided into 5 injections) with Botox under needle EMG guidance. Surface EMG data were evaluated using customised software, and in the individuals gait was analysed using Proreflex. Statistical analysis was performed using mixed models and independent sample t test (P signals were quantified using customised software. The area under the curve (integrated EMG) in time was used as variable. It became significantly reduced in injected muscles after injection of Botox in normal ponies (P signals recorded from injected muscle were reduced, which proves this to be a useful tool in statistically evaluating a treatment effect. The positive results of this pilot study encourage further research with a larger group of clinical cases.

  7. Muscle tissue oxygenation, pressure, electrical, and mechanical responses during dynamic and static voluntary contractions

    DEFF Research Database (Denmark)

    Vedsted, Pernille; Blangsted, Anne Katrine; Søgaard, Karen

    2006-01-01

    Dynamic muscle contractions have been shown to cause greater energy turnover and fatigue than static contractions performed at a corresponding force level. Therefore, we hypothesized that: (1) electro- (EMG) and mechanomyography (MMG), intramuscular pressure (IMP), and reduction in muscle oxygen...... similar in spite of major differences in the MMG and EMG responses of the muscle during contraction periods. This may relate to the surprisingly lower IMP in DYN than IST....

  8. Analysis of High-Density Surface EMG and Finger Pressure in the Left Forearm of Violin Players: A Feasibility Study.

    Science.gov (United States)

    Cattarello, Paolo; Merletti, Roberto; Petracca, Francesco

    2017-09-01

    Wrist and finger flexor muscles of the left hand were evaluated using high-density surface EMG (HDsEMG) in 17 violin players. Pressure sensors also were mounted below the second string of the violin to evaluate, simultaneously, finger pressure. Electrode grid size was 110x70 mm (12x8 electrodes with interelectrode distance=10 mm and Ø=3 mm). The study objective was to observe the activation patterns of these muscles while the violinists sequentially played four notes--SI (B), DO# (C#), RE (D), MI (E)--at 2 bows/s (one bow up in 0.5 s and one down in 0.5 s) and 4 bows/s on the second string, while producing a constant (CONST) or ramp (RAMP) sound volume. HDsEMG images obtained while playing the notes were compared with those obtained during isometric radial or ulnar flexion of the wrist or fingers. Two image descriptors provided information on image differences. Results showed that the technique was reliable and provided reliable signals, and that recognizably different sEMG images could be associated with the four notes tested, despite the variability within and between subjects playing the same note. sEMG activity of the left hand muscles and pressure on the string in the RAMP task were strongly affected in some individuals by the sound volume (controlled by the right hand) and much less in other individuals. These findings question whether there is an individual or generally optimal way of pressing violin strings with the left hand. The answer to this question might substantially modify the teaching of string instruments.

  9. A frequency and pulse-width co-modulation strategy for transcutaneous neuromuscular electrical stimulation based on sEMG time-domain features

    Science.gov (United States)

    Zhou, Yu-Xuan; Wang, Hai-Peng; Bao, Xue-Liang; Lü, Xiao-Ying; Wang, Zhi-Gong

    2016-02-01

    Objective. Surface electromyography (sEMG) is often used as a control signal in neuromuscular electrical stimulation (NMES) systems to enhance the voluntary control and proprioceptive sensory feedback of paralyzed patients. Most sEMG-controlled NMES systems use the envelope of the sEMG signal to modulate the stimulation intensity (current amplitude or pulse width) with a constant frequency. The aims of this study were to develop a strategy that co-modulates frequency and pulse width based on features of the sEMG signal and to investigate the torque-reproduction performance and the level of fatigue resistance achieved with our strategy. Approach. We examined the relationships between wrist torque and two stimulation parameters (frequency and pulse width) and between wrist torque and two sEMG time-domain features (mean absolute value (MAV) and number of slope sign changes (NSS)) in eight healthy volunteers. By using wrist torque as an intermediate variable, customized and generalized transfer functions were constructed to convert the two features of the sEMG signal into the two stimulation parameters, thereby establishing a MAV/NSS dual-coding (MNDC) algorithm. Wrist torque reproduction performance was assessed by comparing the torque generated by the algorithms with that originally recorded during voluntary contractions. Muscle fatigue was assessed by measuring the decline percentage of the peak torque and by comparing the torque time integral of the response to test stimulation trains before and after fatigue sessions. Main Results. The MNDC approach could produce a wrist torque that closely matched the voluntary wrist torque. In addition, a smaller decay in the wrist torque was observed after the MNDC-coded fatigue stimulation was applied than after stimulation using pulse-width modulation alone. Significance. Compared with pulse-width modulation stimulation strategies that are based on sEMG detection, the MNDC strategy is more effective for both voluntary muscle

  10. A frequency and pulse-width co-modulation strategy for transcutaneous neuromuscular electrical stimulation based on sEMG time-domain features.

    Science.gov (United States)

    Zhou, Yu-Xuan; Wang, Hai-Peng; Bao, Xue-Liang; Lü, Xiao-Ying; Wang, Zhi-Gong

    2016-02-01

    Surface electromyography (sEMG) is often used as a control signal in neuromuscular electrical stimulation (NMES) systems to enhance the voluntary control and proprioceptive sensory feedback of paralyzed patients. Most sEMG-controlled NMES systems use the envelope of the sEMG signal to modulate the stimulation intensity (current amplitude or pulse width) with a constant frequency. The aims of this study were to develop a strategy that co-modulates frequency and pulse width based on features of the sEMG signal and to investigate the torque-reproduction performance and the level of fatigue resistance achieved with our strategy. We examined the relationships between wrist torque and two stimulation parameters (frequency and pulse width) and between wrist torque and two sEMG time-domain features (mean absolute value (MAV) and number of slope sign changes (NSS)) in eight healthy volunteers. By using wrist torque as an intermediate variable, customized and generalized transfer functions were constructed to convert the two features of the sEMG signal into the two stimulation parameters, thereby establishing a MAV/NSS dual-coding (MNDC) algorithm. Wrist torque reproduction performance was assessed by comparing the torque generated by the algorithms with that originally recorded during voluntary contractions. Muscle fatigue was assessed by measuring the decline percentage of the peak torque and by comparing the torque time integral of the response to test stimulation trains before and after fatigue sessions. The MNDC approach could produce a wrist torque that closely matched the voluntary wrist torque. In addition, a smaller decay in the wrist torque was observed after the MNDC-coded fatigue stimulation was applied than after stimulation using pulse-width modulation alone. Compared with pulse-width modulation stimulation strategies that are based on sEMG detection, the MNDC strategy is more effective for both voluntary muscle force reproduction and muscle fatigue reduction.

  11. Complexity analysis of EMG signals for patients after stroke during robot-aided rehabilitation training using fuzzy approximate entropy.

    Science.gov (United States)

    Sun, Rui; Song, Rong; Tong, Kai-yu

    2014-09-01

    The paper presents a novel viewpoint to monitor the motor function improvement during a robot-aided rehabilitation training. Eight chronic poststroke subjects were recruited to attend the 20-session training, and in each session, subjects were asked to perform voluntary movements of elbow flexion and extension together with the robotic system. The robotic system was continuously controlled by the electromyographic (EMG) signal from the affected triceps. Fuzzy approximate entropy (fApEn) was applied to investigate the complexity of the EMG segment, and maximum voluntary contraction (MVC) during elbow flexion and extension was applied to reflect force generating capacity of the affected muscles. The results showed that the group mean fApEn of EMG signals from triceps and biceps increased significantly after the robot-aided rehabilitation training . There was also significant increase in maximum voluntary flexion and extension torques after the robot-aided rehabilitation training . There was significant correlation between fApEn of agonist and MVC , which implied that the increase of motorneuron number is one of factors that may explain the increase in muscle strength. These findings based on fApEn of the EMG signals expand the existing interpretation of training-induced function improvement in patients after stroke, and help us to understand the neurological change induced by the robot-aided rehabilitation training.

  12. Quadriceps Muscle Function during Recreational Alpine Skiing.

    Science.gov (United States)

    Kröll, Josef; Wakeling, James M; Seifert, John G; Müller, Erich

    2010-08-01

    Since the introduction of carving skis, muscle activity has been investigated primarily on expert-level skiers with respect to EMG intensities. The three-part aim of this recreational skiing study was to analyze functional differences within the quadriceps muscle, to analyze the topographical influence, and to apply a time-frequency analysis of the EMG intensities using wavelets. Seven female subjects performed two runs through a standardized corridor on a slope with different inclinations (13 degrees , 29 degrees , and 21 degrees ). Knee angle and EMG of vastus lateralis (VL) and rectus femoris (RF) of the right leg were measured during the runs. The recorded EMG signal was resolved with a set of 10 wavelets (11-432 Hz) into a time-frequency space. Subsequently, the EMG intensity and mean frequency (MF) were calculated for different time windows (inside leg; outside leg). For RF, a significantly higher MF (+15.5%, P = 0.009) but similar EMG intensities were detected in the inside leg compared with the outside leg. For VL, the MF (-9.6%, P = 0.053) and EMG intensities (-54.3%, P = 0.010) were lower in the inside leg compared with the outside leg. Both muscles responded with higher EMG intensities on increasing slope inclination (VL = 90.8%, P = 0.022; RF = 115%, P = 0.01). MF is not directly related to inclination. Contrary to previously suggested coloading of the inside leg while carving, our results do not support this hypothesis for VL. However, the functional demand for RF in the inside leg is very high when skiing recreationally. The ability of a situation-dependent loading (RF as knee extensor) and unloading (RF as hip flexor) of the inside leg seems to be a crucial point with respect to specific fatigue during a skiing day.

  13. Are muscle synergies useful for neural control ?

    Directory of Open Access Journals (Sweden)

    Aymar ede Rugy

    2013-03-01

    Full Text Available The observation that the activity of multiple muscles can be well approximated by a few linear synergies is viewed by some as a sign that such low-dimensional modules constitute a key component of the neural control system. Here, we argue that the usefulness of muscle synergies as a control principle should be evaluated in terms of errors produced not only in muscle space, but also in task space. We used data from a force-aiming task in two dimensions at the wrist, using an EMG-driven virtual biomechanics technique that overcomes typical errors in predicting force from recorded EMG, to illustrate through simulation how synergy decomposition inevitably introduces substantial task space errors. Then, we computed the optimal pattern of muscle activation that minimizes summed-squared muscle activities, and demonstrated that synergy decomposition produced similar results on real and simulated data. We further assessed the influence of synergy decomposition on aiming errors in a more redundant system, using the optimal muscle pattern computed for the elbow-joint complex (i.e., 13 muscles acting in two dimensions. Because EMG records are typically not available from all contributing muscles, we also explored reconstructions from incomplete sets of muscles. The redundancy of a given set of muscles had opposite effects on the goodness of muscle reconstruction and on task achievement; higher redundancy is associated with better EMG approximation (lower residuals, but with higher aiming errors. Finally, we showed that the number of synergies required to approximate the optimal muscle pattern for an arbitrary biomechanical system increases with task-space dimensionality, which indicates that the capacity of synergy decomposition to explain behaviour depends critically on the scope of the original database. These results have implications regarding the viability of muscle synergy as a putative neural control mechanism, and also as a control algorithm to

  14. Quantifying forearm muscle activity during wrist and finger movements by means of multi-channel electromyography.

    Directory of Open Access Journals (Sweden)

    Marco Gazzoni

    Full Text Available The study of hand and finger movement is an important topic with applications in prosthetics, rehabilitation, and ergonomics. Surface electromyography (sEMG is the gold standard for the analysis of muscle activation. Previous studies investigated the optimal electrode number and positioning on the forearm to obtain information representative of muscle activation and robust to movements. However, the sEMG spatial distribution on the forearm during hand and finger movements and its changes due to different hand positions has never been quantified. The aim of this work is to quantify 1 the spatial localization of surface EMG activity of distinct forearm muscles during dynamic free movements of wrist and single fingers and 2 the effect of hand position on sEMG activity distribution. The subjects performed cyclic dynamic tasks involving the wrist and the fingers. The wrist tasks and the hand opening/closing task were performed with the hand in prone and neutral positions. A sensorized glove was used for kinematics recording. sEMG signals were acquired from the forearm muscles using a grid of 112 electrodes integrated into a stretchable textile sleeve. The areas of sEMG activity have been identified by a segmentation technique after a data dimensionality reduction step based on Non Negative Matrix Factorization applied to the EMG envelopes. The results show that 1 it is possible to identify distinct areas of sEMG activity on the forearm for different fingers; 2 hand position influences sEMG activity level and spatial distribution. This work gives new quantitative information about sEMG activity distribution on the forearm in healthy subjects and provides a basis for future works on the identification of optimal electrode configuration for sEMG based control of prostheses, exoskeletons, or orthoses. An example of use of this information for the optimization of the detection system for the estimation of joint kinematics from sEMG is reported.

  15. Quantifying Forearm Muscle Activity during Wrist and Finger Movements by Means of Multi-Channel Electromyography

    Science.gov (United States)

    Gazzoni, Marco; Celadon, Nicolò; Mastrapasqua, Davide; Paleari, Marco; Margaria, Valentina; Ariano, Paolo

    2014-01-01

    The study of hand and finger movement is an important topic with applications in prosthetics, rehabilitation, and ergonomics. Surface electromyography (sEMG) is the gold standard for the analysis of muscle activation. Previous studies investigated the optimal electrode number and positioning on the forearm to obtain information representative of muscle activation and robust to movements. However, the sEMG spatial distribution on the forearm during hand and finger movements and its changes due to different hand positions has never been quantified. The aim of this work is to quantify 1) the spatial localization of surface EMG activity of distinct forearm muscles during dynamic free movements of wrist and single fingers and 2) the effect of hand position on sEMG activity distribution. The subjects performed cyclic dynamic tasks involving the wrist and the fingers. The wrist tasks and the hand opening/closing task were performed with the hand in prone and neutral positions. A sensorized glove was used for kinematics recording. sEMG signals were acquired from the forearm muscles using a grid of 112 electrodes integrated into a stretchable textile sleeve. The areas of sEMG activity have been identified by a segmentation technique after a data dimensionality reduction step based on Non Negative Matrix Factorization applied to the EMG envelopes. The results show that 1) it is possible to identify distinct areas of sEMG activity on the forearm for different fingers; 2) hand position influences sEMG activity level and spatial distribution. This work gives new quantitative information about sEMG activity distribution on the forearm in healthy subjects and provides a basis for future works on the identification of optimal electrode configuration for sEMG based control of prostheses, exoskeletons, or orthoses. An example of use of this information for the optimization of the detection system for the estimation of joint kinematics from sEMG is reported. PMID:25289669

  16. The distribution and propagation pattern of motor unit action potentials studied by multi-channel surface EMG.

    Science.gov (United States)

    Yamada, M; Kumagai, K; Uchiyama, A

    1987-11-01

    We developed the multi-channel surface EMG system using a matrix-type of surface electrode and with the aid of digital signal processing. The subjects were 14 normals (4-50 years) and 2 patients with Duchenne muscular dystrophy (7 and 8 years). The biceps brachii and the tibialis anterior muscles were investigated. The location of the motor end-plates and the measurement of muscle fiber conduction velocity were evaluated by the time shift of bipolar EMG arrays along muscle fibers, or by the distribution map of averaged motor unit action potentials (MUAPs). The lateral extension of a motor unit could be also estimated from the changes of averaged MUAP's amplitudes in the distribution map. Moreover in the biceps of 2 patients with Duchenne dystrophy, the mean muscle fiber conduction velocities were reduced compared to normal subjects, and characteristic propagation patterns of action potentials were obtained. In the 2-dimensional or 3-dimensional distribution map of integrated monopolar EMGs, the high density area agreed with the motor end-plate band.

  17. Electrically and hybrid-induced muscle activations: effects of muscle size and fiber type

    Directory of Open Access Journals (Sweden)

    Kelly Stratton

    2016-07-01

    Full Text Available The effect of three electrical stimulation (ES frequencies (10, 35, and 50 Hz on two muscle groups with different proportions of fast and slow twitch fibers (abductor pollicis brevis (APB and vastus lateralis (VL was explored. We evaluated the acute muscles’ responses individually and during hybrid activations (ES superimposed by voluntary activations. Surface electromyography (sEMG and force measurements were evaluated as outcomes. Ten healthy adults (mean age: 24.4 ± 2.5 years participated after signing an informed consent form approved by the university Institutional Review Board. Protocols were developed to: 1 compare EMG activities during each frequency for each muscle when generating 25% Maximum Voluntary Contraction (MVC force, and 2 compare EMG activities during each frequency when additional voluntary activation was superimposed over ES-induced 25% MVC to reach 50% and 75% MVC. Empirical mode decomposition (EMD was utilized to separate ES artifacts from voluntary muscle activation. For both muscles, higher stimulation frequency (35 and 50Hz induced higher electrical output detected at 25% of MVC, suggesting more recruitment with higher frequencies. Hybrid activation generated proportionally less electrical activity than ES alone. ES and voluntary activations appear to generate two different modes of muscle recruitment. ES may provoke muscle strength by activating more fatiguing fast acting fibers, but voluntary activation elicits more muscle coordination. Therefore, during the hybrid activation, less electrical activity may be detected due to recruitment of more fatigue-resistant deeper muscle fibers, not reachable by surface EMG.

  18. Measurement of muscle length-related electromyography activity of the hip flexor muscles to determine individual muscle contributions to the hip flexion torque.

    Science.gov (United States)

    Jiroumaru, Takumi; Kurihara, Toshiyuki; Isaka, Tadao

    2014-01-01

    This study aimed to investigate muscle length-related electromyography (EMG) of the iliopsoas (IL) and other hip flexor muscles to determine individual muscle contributions to the hip flexion torque. Ten healthy sedentary young men participated in the EMG experiment. A subgroup of six subjects underwent a magnetic resonance imaging (MRI) measurement to confirm the region of the skin over the IL. Surface EMG signals were sampled from the IL, rectus femoris (RF), sartorius (SA), and tensor fasciae latae (TFL) using an active electrode. The subjects performed maximum voluntary isometric hip flexion with the right hip joint set at -10°, 0°, 30°, and 60°. The root mean square (RMS) value for the TFL at 30° (0.81 ± 0.19, p muscle length changes were significantly correlated in the IL (r =0.39, p muscles.

  19. Ultrasonic Measurement of Dynamic Muscle Behavior for Poststroke Hemiparetic Gait

    Directory of Open Access Journals (Sweden)

    Xin Chen

    2017-01-01

    Full Text Available Quantitative evaluation of the hemiparesis status for a poststroke patient is still challenging. This study aims to measure and investigate the dynamic muscle behavior in poststroke hemiparetic gait using ultrasonography. Twelve hemiparetic patients walked on a treadmill, and EMG, joint angle, and ultrasonography were simultaneously recorded for the gastrocnemius medialis muscle. Pennation angle was automatically extracted from ultrasonography using a tracking algorithm reported previously. The characteristics of EMG, joint angle, and pennation angle in gait cycle were calculated for both (affected and unaffected sides of lower limbs. The results suggest that pennation angle could work as an important morphological index to continuous muscle contraction. The change pattern of pennation angle between the affected and unaffected sides is different from that of EMG. These findings indicate that morphological parameter extracted from ultrasonography can provide different information from that provided by EMG for hemiparetic gait.

  20. Relative efficacy of transcranial motor evoked potentials, mechanically-elicited electromyography, and evoked EMG to assess nerve root function during sustained retraction in a porcine model.

    Science.gov (United States)

    Lyon, Russ; Lieberman, Jeremy A; Feiner, John; Burch, Shane

    2009-07-15

    This is an animal experiment using transcranial motor evoked potentials (TcMEP), mechanically elicited electromyography (EMG), and evoked EMG during spinal nerve root retraction in a pig model. To compare the sensitivity of these 3 electrophysiological measures for a constant retraction force applied to an isolated lumbar nerve root for a specific duration of time. The incidence of nerve root injury during lumbar spine surgery ranges from 0.2% to 31%. Direct retraction of spinal nerve roots may cause these injuries, but the amount and duration of force that may safely be applied is not clear. Using an established porcine model, we examined the changes occurring to multimyotomal TcMEPs, mechanically elicited EMGs, and evoked EMGs during continuous retraction of a nerve root at a constant force applied over 10 minutes. TcMEP, mechanically elicited EMG, and evoked EMG responses were recorded from the tibialis anterior (TA) muscle in 10 experiments. The dominant root innervating the TA was determined with evoked EMG; preretraction TcMEP and nerve root stimulation threshold (NRT) was obtained. The dominant root was retracted at 2 Newton (N) for 10 minutes. TcMEP trials were elicited every minute during retraction. NRT was measured immediately after retraction. TcMEP and NRT were measured after 10 minutes of recovery. RESULTS.: During the 10 minutes of retraction at 2 N, the amplitude of the TA muscle progressively decreased in all trials in a highly significant curvilinear fashion. The mean TcMEP amplitude decreased 59% +/- 14% from baseline values. The mean NRT after 10 minutes of retraction at 2 N rose to 1.8 +/- 0.7 mA (P EMG activity was variable; tonic EMG was observed in only 2 nerve roots (20%). Three electrophysiologic methods were used intraoperatively to assess neural function during retraction of a single nerve root. Retraction produced consistent changes in TcMEPs and evoked EMG. These 2 methods show promise for assessing the limits on the force and duration

  1. Robot Control Using Electromyography (EMG Signals of the Wrist

    Directory of Open Access Journals (Sweden)

    C. DaSalla

    2005-01-01

    Full Text Available The aim of this paper is to design a human–interface system, using EMG signals elicited by various wrist movements, to control a robot. EMG signals are normalized and based on joint torque. A three-layer neural network is used to estimate posture of the wrist and forearm from EMG signals. After training the neural network and obtaining appropriate weights, the subject was able to control the robot in real time using wrist and forearm movements.

  2. Extracting time-frequency feature of single-channel vastus medialis EMG signals for knee exercise pattern recognition.

    Science.gov (United States)

    Zhang, Yi; Li, Peiyang; Zhu, Xuyang; Su, Steven W; Guo, Qing; Xu, Peng; Yao, Dezhong

    2017-01-01

    The EMG signal indicates the electrophysiological response to daily living of activities, particularly to lower-limb knee exercises. Literature reports have shown numerous benefits of the Wavelet analysis in EMG feature extraction for pattern recognition. However, its application to typical knee exercises when using only a single EMG channel is limited. In this study, three types of knee exercises, i.e., flexion of the leg up (standing), hip extension from a sitting position (sitting) and gait (walking) are investigated from 14 healthy untrained subjects, while EMG signals from the muscle group of vastus medialis and the goniometer on the knee joint of the detected leg are synchronously monitored and recorded. Four types of lower-limb motions including standing, sitting, stance phase of walking, and swing phase of walking, are segmented. The Wavelet Transform (WT) based Singular Value Decomposition (SVD) approach is proposed for the classification of four lower-limb motions using a single-channel EMG signal from the muscle group of vastus medialis. Based on lower-limb motions from all subjects, the combination of five-level wavelet decomposition and SVD is used to comprise the feature vector. The Support Vector Machine (SVM) is then configured to build a multiple-subject classifier for which the subject independent accuracy will be given across all subjects for the classification of four types of lower-limb motions. In order to effectively indicate the classification performance, EMG features from time-domain (e.g., Mean Absolute Value (MAV), Root-Mean-Square (RMS), integrated EMG (iEMG), Zero Crossing (ZC)) and frequency-domain (e.g., Mean Frequency (MNF) and Median Frequency (MDF)) are also used to classify lower-limb motions. The five-fold cross validation is performed and it repeats fifty times in order to acquire the robust subject independent accuracy. Results show that the proposed WT-based SVD approach has the classification accuracy of 91.85%±0.88% which

  3. Trunk muscle activity during front crawl swimming

    OpenAIRE

    Martens, Jonas; Pellegrims, Ward; Einarsson, Ingi Thor; Fernandes, Ricardo; Staes, Filip; Daly, Daniel

    2013-01-01

    Introduction Core stability training is of increasing interest to both researchers and coaches. Sufficient core stability is needed to balance forces generated by the upper and lower extremities separately (Hibbs et al., 2008). In swimming the development of wireless EMG has created new possibilities to study underwater muscle activity with little hinder. The purpose here was to analyze lower trunk muscle activation during front crawl swimming and examine how trunk muscle activity is relat...

  4. Surface EMG measurements during fMRI at 3T : Accurate EMG recordings after artifact correction

    NARCIS (Netherlands)

    van Duinen, Hiske; Zijdewind, Inge; Hoogduin, H; Maurits, N

    2005-01-01

    In this experiment, we have measured surface EMG of the first dorsal interosseus during predefined submaximal isometric contractions (5, 15, 30, 50, and 70% of maximal force) of the index finger simultaneously with fMRI measurements. Since we have used sparse sampling fMRI (3-s scanning; 2-s

  5. Acute Warm-up Effects in Submaximal Athletes: An EMG Study of Skilled Violinists.

    Science.gov (United States)

    McCrary, J Matt; Halaki, Mark; Sorkin, Evgeny; Ackermann, Bronwen J

    2016-02-01

    Warm-up is commonly recommended for injury prevention and performance enhancement across all activities, yet this recommendation is not supported by evidence for repetitive submaximal activities such as instrumental music performance. The objective of this study is to quantify the effects of cardiovascular, core muscle, and musical warm-ups on muscle activity levels, musical performance, and subjective experience in skilled violinists. Fifty-five undergraduate, postgraduate, or professional violinists performed five randomly ordered 45-s musical excerpts of varying physical demands both before and after a randomly assigned 15-min, moderate-intensity cardiovascular, core muscle, musical (technical violin exercises), or inactive control warm-up protocol. Surface EMG data were obtained for 16 muscles of the trunk, shoulders, and right arm during each musical performance. Sound recording and perceived exertion (RPE) data were also obtained. Sound recordings were randomly ordered and rated for performance quality by blinded adjudicators. Questionnaire data regarding participant pain sites and fitness levels were used to stratify participants according to pain and fitness levels. Data were analyzed using two- and three-factor ANCOVA (surface EMG and sound recording) and Wilcoxon matched pairs tests (RPE). None of the three warm-up protocols had significant effects on muscle activity levels (P ≥ 0.10). Performance quality did not significantly increase (P ≥ 0.21). RPE significantly decreased (P 0.23). Acute physiological and musical benefits from cardiovascular, core muscle, and musical warm-ups in skilled violinists are limited to decreases in RPE. This investigation provides data from the performing arts in support of sports medical evidence suggesting that warm-up only effectively enhances maximal strength and power performance.

  6. High efficiency and simple technique for controlling mechanisms by EMG signals

    Science.gov (United States)

    Dugarte, N.; Álvarez, A.; Balacco, J.; Mercado, G.; Gonzalez, A.; Dugarte, E.; Javier, F.; Ceballos, G.; Olivares, A.

    2016-04-01

    This article reports the development of a simple and efficient system that allows control of mechanisms through electromyography (EMG) signals. The novelty about this instrument is focused on individual control of each motion vector mechanism through independent electronic circuits. Each of electronic circuit does positions a motor according to intensity of EMG signal captured. This action defines movement in one mechanical axis considered from an initial point, based on increased muscle tension. The final displacement of mechanism depends on individual’s ability to handle the levels of muscle tension at different body parts. This is the design of a robotic arm where each degree of freedom is handled with a specific microcontroller that responds to signals taken from a defined muscle. The biophysical interaction between the person and the final positioning of the robotic arm is used as feedback. Preliminary tests showed that the control operates with minimal positioning error margins. The constant use of system with the same operator showed that the person adapts and progressively improves at control technique.

  7. Analysis of EMG temporal parameters from the tibialis anterior during hemiparetic gait

    Science.gov (United States)

    Bonell, Claudia E.; Cherniz, Analía S.; Tabernig, Carolina B.

    2007-11-01

    Functional electrical stimulation is a rehabilitation technique used to restore the motor muscular function by means of electrical stimulus commanded by a trigger signal under volitional control. In order to enhance the motor rehabilitation, a more convenient control signal may be provided by the same muscle that is being stimulated. For example, the tibialis anterior (TA) in the applications of foot drop correction could be used. This work presents the statistical analysis of the root mean square (RMS) and the absolute mean value (VMA) of the TA electromyogram (EMG) signal computed from different phases of the gait cycle related with increases/decreases stages of muscle activity. The EMG records of 40 strides of 2 subjects with hemiparesia were processed. The RMS and VMA parameters allow distinguishing the oscillation phase from the other analyzed intervals, but they present significant spreading of mean values. This led to conclude that it is possible to use these parameters to identify the start of TA muscle activity, but altogether with other parameter or sensor that would reduce the number of false positives.

  8. Surface EMG to assess arm function in boys with DMD: a pilot study.

    Science.gov (United States)

    Janssen, Mariska M H P; Harlaar, Jaap; de Groot, Imelda J M

    2015-04-01

    Preserving functional abilities of the upper extremities is a major concern in boys with Duchenne Muscular Dystrophy (DMD). To assess disease progression and treatments, good knowledge on arm function in boys with DMD is essential. Therefore, feasibility and validity of the use of surface electromyography (sEMG) to assess arm function in boys with DMD was examined. Five boys with DMD and 6 age-matched controls participated in this study. Single joint movements and ADL activities were examined while recording sEMG of main shoulder and elbow muscles. All boys with DMD and controls were able to perform the non standardized movements of the measurement protocol, however one boy with DMD was not able to perform all the standardized movements. Boys with DMD used significantly more of their maximal muscle capacity for all muscles to conduct movements compared to controls. The measurement protocol was feasible to assess arm function in boys with DMD. This tool was able to discriminate between DMD patients and controls. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. Analysis of EMG temporal parameters from the tibialis anterior during hemiparetic gait

    Energy Technology Data Exchange (ETDEWEB)

    Bonell, Claudia E; Cherniz, AnalIa S; Tabernig, Carolina B [Laboratorio de Ingenieria de Rehabilitacion e Investigaciones Neuromusculares y Sensoriales, Facultad de Ingenieria, UNER, Oro Verde (Argentina)

    2007-11-15

    Functional electrical stimulation is a rehabilitation technique used to restore the motor muscular function by means of electrical stimulus commanded by a trigger signal under volitional control. In order to enhance the motor rehabilitation, a more convenient control signal may be provided by the same muscle that is being stimulated. For example, the tibialis anterior (TA) in the applications of foot drop correction could be used. This work presents the statistical analysis of the root mean square (RMS) and the absolute mean value (VMA) of the TA electromyogram (EMG) signal computed from different phases of the gait cycle related with increases/decreases stages of muscle activity. The EMG records of 40 strides of 2 subjects with hemiparesia were processed. The RMS and VMA parameters allow distinguishing the oscillation phase from the other analyzed intervals, but they present significant spreading of mean values. This led to conclude that it is possible to use these parameters to identify the start of TA muscle activity, but altogether with other parameter or sensor that would reduce the number of false positives.

  10. Optimal Elbow Angle for Extracting sEMG Signals During Fatiguing Dynamic Contraction

    Directory of Open Access Journals (Sweden)

    Mohamed R. Al-Mulla

    2015-09-01

    Full Text Available Surface electromyographic (sEMG activity of the biceps muscle was recorded from 13 subjects. Data was recorded while subjects performed dynamic contraction until fatigue and the signals were segmented into two parts (Non-Fatigue and Fatigue. An evolutionary algorithm was used to determine the elbow angles that best separate (using Davies-Bouldin Index, DBI both Non-Fatigue and Fatigue segments of the sEMG signal. Establishing the optimal elbow angle for feature extraction used in the evolutionary process was based on 70% of the conducted sEMG trials. After completing 26 independent evolution runs, the best run containing the optimal elbow angles for separation (Non-Fatigue and Fatigue was selected and then tested on the remaining 30% of the data to measure the classification performance. Testing the performance of the optimal angle was undertaken on nine features extracted from each of the two classes (Non-Fatigue and Fatigue to quantify the performance. Results showed that the optimal elbow angles can be used for fatigue classification, showing 87.90% highest correct classification for one of the features and on average of all eight features (including worst performing features giving 78.45%.

  11. Simultaneous and Continuous Estimation of Shoulder and Elbow Kinematics from Surface EMG Signals

    Science.gov (United States)

    Zhang, Qin; Liu, Runfeng; Chen, Wenbin; Xiong, Caihua

    2017-01-01

    In this paper, we present a simultaneous and continuous kinematics estimation method for multiple DoFs across shoulder and elbow joint. Although simultaneous and continuous kinematics estimation from surface electromyography (EMG) is a feasible way to achieve natural and intuitive human-machine interaction, few works investigated multi-DoF estimation across the significant joints of upper limb, shoulder and elbow joints. This paper evaluates the feasibility to estimate 4-DoF kinematics at shoulder and elbow during coordinated arm movements. Considering the potential applications of this method in exoskeleton, prosthetics and other arm rehabilitation techniques, the estimation performance is presented with different muscle activity decomposition and learning strategies. Principle component analysis (PCA) and independent component analysis (ICA) are respectively employed for EMG mode decomposition with artificial neural network (ANN) for learning the electromechanical association. Four joint angles across shoulder and elbow are simultaneously and continuously estimated from EMG in four coordinated arm movements. By using ICA (PCA) and single ANN, the average estimation accuracy 91.12% (90.23%) is obtained in 70-s intra-cross validation and 87.00% (86.30%) is obtained in 2-min inter-cross validation. This result suggests it is feasible and effective to use ICA (PCA) with single ANN for multi-joint kinematics estimation in variant application conditions. PMID:28611573

  12. Are external knee load and EMG measures accurate indicators of internal knee contact forces during gait?

    Science.gov (United States)

    Meyer, Andrew J; D'Lima, Darryl D; Besier, Thor F; Lloyd, David G; Colwell, Clifford W; Fregly, Benjamin J

    2013-06-01

    Mechanical loading is believed to be a critical factor in the development and treatment of knee osteoarthritis. However, the contact forces to which the knee articular surfaces are subjected during daily activities cannot be measured clinically. Thus, the ability to predict internal knee contact forces accurately using external measures (i.e., external knee loads and muscle electromyographic [EMG] signals) would be clinically valuable. We quantified how well external knee load and EMG measures predict internal knee contact forces during gait. A single subject with a force-measuring tibial prosthesis and post-operative valgus alignment performed four gait patterns (normal, medial thrust, walking pole, and trunk sway) to induce a wide range of external and internal knee joint loads. Linear regression analyses were performed to assess how much of the variability in internal contact forces was accounted for by variability in the external measures. Though the different gait patterns successfully induced significant changes in the external and internal quantities, changes in external measures were generally weak indicators of changes in total, medial, and lateral contact force. Our results suggest that when total contact force may be changing, caution should be exercised when inferring changes in knee contact forces based on observed changes in external knee load and EMG measures. Advances in musculoskeletal modeling methods may be needed for accurate estimation of in vivo knee contact forces. Copyright © 2012 Orthopaedic Research Society.

  13. Simultaneous and Continuous Estimation of Shoulder and Elbow Kinematics from Surface EMG Signals

    Directory of Open Access Journals (Sweden)

    Qin Zhang

    2017-05-01

    Full Text Available In this paper, we present a simultaneous and continuous kinematics estimation method for multiple DoFs across shoulder and elbow joint. Although simultaneous and continuous kinematics estimation from surface electromyography (EMG is a feasible way to achieve natural and intuitive human-machine interaction, few works investigated multi-DoF estimation across the significant joints of upper limb, shoulder and elbow joints. This paper evaluates the feasibility to estimate 4-DoF kinematics at shoulder and elbow during coordinated arm movements. Considering the potential applications of this method in exoskeleton, prosthetics and other arm rehabilitation techniques, the estimation performance is presented with different muscle activity decomposition and learning strategies. Principle component analysis (PCA and independent component analysis (ICA are respectively employed for EMG mode decomposition with artificial neural network (ANN for learning the electromechanical association. Four joint angles across shoulder and elbow are simultaneously and continuously estimated from EMG in four coordinated arm movements. By using ICA (PCA and single ANN, the average estimation accuracy 91.12% (90.23% is obtained in 70-s intra-cross validation and 87.00% (86.30% is obtained in 2-min inter-cross validation. This result suggests it is feasible and effective to use ICA (PCA with single ANN for multi-joint kinematics estimation in variant application conditions.

  14. Development of Hand Grip Assistive Device Control System for Old People through Electromyography (EMG Signal Acquisitions

    Directory of Open Access Journals (Sweden)

    Khamis Herman

    2017-01-01

    Full Text Available The hand grip assistive device is a glove to assist old people who suffer from hand weakness in their daily life activities. The device earlier control system only use simple on and off switch. This required old people to use both hand to activate the device. The new control system of the hand grip assistive device was developed to allow single hand operation for old people. New control system take advantages of electromyography (EMG and flex sensor which was implemented to the device. It was programmed into active and semi-active mode operation. EMG sensors were placed on the forearm to capture EMG signal of Flexor Digitorum Profundus muscle to activate the device. Flex sensor was used to indicate the finger position and placed on top of the finger. The signal from both sensors then used to control the device. The new control system allowed single hand operation and designed to prevent user from over depended on the device by activating it through moving their fingers.

  15. Estimation of Ligament Loading and Anterior Tibial Translation in Healthy and ACL-Deficient Knees During Gait and the Influence of Increasing Tibial Slope Using EMG-Driven Approach

    OpenAIRE

    Shao, Qi; MacLeod, Toran D.; Manal, Kurt; Buchanan, Thomas S.

    2010-01-01

    The purpose of this study was to develop a biomechanical model to estimate anterior tibial translation (ATT), anterior shear forces, and ligament loading in the healthy and anterior cruciate ligament (ACL)-deficient knee joint during gait. This model used electromyography (EMG), joint position, and force plate data as inputs to calculate ligament loading during stance phase. First, an EMG-driven model was used to calculate forces for the major muscles crossing the knee joint. The calculated m...

  16. The effect of handedness on electromyographic activity of human shoulder muscles during movement

    DEFF Research Database (Denmark)

    Diederichsen, Louise Pyndt; Nørregaard, Jesper; Dyhre-Poulsen, Poul

    2006-01-01

    The aim of the study was to investigate whether there was a difference in the electromyographic (EMG) activity of human shoulder muscles between the dominant and nondominant side during movement and to explore whether a possible side-difference depends on the specific task. We compared the EMG ac...

  17. Task-related variations in motoneuronal drive to a human intrinsic hand muscle

    NARCIS (Netherlands)

    Zijdewind, Inge; de Groot, MCH; Kernell, D

    1998-01-01

    Maximal electromyogram (EMG) levels of the first dorsal interosseus muscle (FDI) were studied during maximal pinching between index finger and thumb at two different wrist angles. Despite the fact that there was no change in the biomechanical conditions for the FDI, the maximal EMG levels of the FDI

  18. Spatial variability in cortex-muscle coherence investigated with magnetoencephalography and high-density surface electromyography

    Science.gov (United States)

    Botter, Alberto; Bourguignon, Mathieu; Jousmäki, Veikko; Hari, Riitta

    2015-01-01

    Cortex-muscle coherence (CMC) reflects coupling between magnetoencephalography (MEG) and surface electromyography (sEMG), being strongest during isometric contraction but absent, for unknown reasons, in some individuals. We used a novel nonmagnetic high-density sEMG (HD-sEMG) electrode grid (36 mm × 12 mm; 60 electrodes separated by 3 mm) to study effects of sEMG recording site, electrode derivation, and rectification on the strength of CMC. Monopolar sEMG from right thenar and 306-channel whole-scalp MEG were recorded from 14 subjects during 4-min isometric thumb abduction. CMC was computed for 60 monopolar, 55 bipolar, and 32 Laplacian HD-sEMG derivations, and two derivations were computed to mimic “macroscopic” monopolar and bipolar sEMG (electrode diameter 9 mm; interelectrode distance 21 mm). With unrectified sEMG, 12 subjects showed statistically significant CMC in 91–95% of the HD-sEMG channels, with maximum coherence at ∼25 Hz. CMC was about a fifth stronger for monopolar than bipolar and Laplacian derivations. Monopolar derivations resulted in most uniform CMC distributions across the thenar and in tightest cortical source clusters in the left rolandic hand area. CMC was 19–27% stronger for HD-sEMG than for “macroscopic” monopolar or bipolar derivations. EMG rectification reduced the CMC peak by a quarter, resulted in a more uniformly distributed CMC across the thenar, and provided more tightly clustered cortical sources than unrectifed sEMGs. Moreover, it revealed CMC at ∼12 Hz. We conclude that HD-sEMG, especially with monopolar derivation, can facilitate detection of CMC and that individual muscle anatomy cannot explain the high interindividual CMC variability. PMID:26354317

  19. EMGTools, an adaptive and versatile tool for detailed EMG analysis

    DEFF Research Database (Denmark)

    Nikolic, M; Krarup, C

    2010-01-01

    We have developed an EMG decomposition system called EMGTools that can extract the constituent MUAPs and firing patterns for quantitative analysis from the EMG signal recorded at slight effort for clinical evaluation. The aim was to implement a robust system able to handle the challenges...

  20. Seizure Onset Detection based on one sEMG channel

    DEFF Research Database (Denmark)

    Conradsen, Isa; Beniczky, Sandor; Hoppe, Karsten

    2011-01-01

    We present a new method to detect seizure onsets of tonic-clonic epileptic seizures based on surface electromyography (sEMG) data. The proposed method is generic and based on a single channel making it ideal for a small detection or monitoring device. The sEMG signal is high-pass filtered with a ...

  1. Training to improve volitional muscle activity in clinically paralyzed muscles for neuroprosthesis control.

    Science.gov (United States)

    Moss, Christa W; Kilgore, Kevin L; Peckham, P Hunter

    2011-01-01

    Neuroprostheses are devices that use electrical stimulation to activate paralyzed muscles in a coordinated manner to restore functional movements. These systems utilize a voluntarily-generated command signal for control of function. Current command signals include electromyographic (EMG) activity from muscles above the injury level that remain under volitional control. In individuals with cervical level spinal cord injury (SCI), these signal sources are limited in number. Our recent research suggests that volitional muscle activity from below the injury level in individuals with motor complete spinal cord injury may be a viable source of command information. The signals from these muscles are small, and therefore the goal of this study is to determine if training using visual feedback can improve the quality of these muscle signals. Results to date indicate that training with visual feedback can increase both the magnitude and consistency of EMG signals in clinically paralyzed muscles.

  2. An EMG Decomposition System Aimed at Detailed Analysis of Motor Unit Activity

    DEFF Research Database (Denmark)

    Nikolic, Mile; Krarup, Christian; Dahl, Kristian

    1997-01-01

    Decomposition of EMG signals by segmentation oftime signals, clustering and resolving of compoundsegments.......Decomposition of EMG signals by segmentation oftime signals, clustering and resolving of compoundsegments....

  3. Analysis of maximal isometric force and EMG signal in lower limb exercise. 10.5007/1980-0037.2011v13n6p429

    OpenAIRE

    Cleiton Silva Correa; Bruna Gonçalves Cordeiro da Silva; Cristine Lima Alberton; Eurico Nestor Wilhelm Neto; Antonio Carlos de Moraes; Claudia Silveira Lima; Ronei Silveira Pinto

    2011-01-01

    The aim of this study was to compare maximal isometric force (MIF) and the electrical activity of the vastus medialis, vastus lateralis, rectus femoris, gluteus maximus and biceps femoris long head muscles between maximal voluntary contractions (MVC) performed at different joint angles, and to identify the most suitable positions to normalize the electromyography (EMG) signals from each of these muscles when they are activated under dynamic conditions. Ten men ranging in age from 20 to 30 yea...

  4. Multi-stream HMM for EMG-based speech recognition.

    Science.gov (United States)

    Manabe, H; Zhang, Z

    2004-01-01

    A technique for improving the recognition accuracy of EMG-based speech recognition by applying existing speech recognition technologies is proposed. The authors have proposed an EMG-based speech recognition system that requires only mouth movements, voice need not be generated. A multi-stream HMM (hidden Markov model) and feature extraction technique are applied to EMG-based speech recognition. 3 channel facial EMG signals are collected from ten subjects when uttering 10 Japanese isolated digits. One channel corresponds to one stream. By examining various features, we found that the delta component of the static parameter leads to higher accuracy. Compared to equal stream weighting, the individual optimization of stream weights increased recognition accuracy by 4.0% which corresponds to a 12.8% reduction in error rate. This result shows that multistream HMM is effective for the classification of EMG.

  5. Optimizing muscle selection for electromyography in amyotrophic lateral sclerosis.

    Science.gov (United States)

    Babu, Suma; Pioro, Erik P; Li, Jianbo; Li, Yuebing

    2017-07-01

    We compared the yield of limb and thoracic paraspinal muscle examination for revealing lower motor neuron (LMN) dysfunction on electromyography (EMG) in amyotrophic lateral sclerosis (ALS). A retrospective review of 354 patients with clinically definite or probable ALS was performed. Seventeen limb muscles and thoracic paraspinal muscles were evaluated for the presence of both active and chronic denervation. Distal limb muscles showed the highest electrodiagnostic sensitivities of LMN dysfunction in ALS regardless of onset region and diagnostic certainty at the time of diagnosis. Electrodiagnostic yield is higher in muscles from the onset limb. Noncontiguous spread of lower motor neuron degeneration is present in ALS. Optimally selected 6 upper and 5 lower extremity muscles yielded >98% of potential positive cervical or lumbosacral segments. An algorithmic approach to needle EMG in ALS based on pretest probability of individual muscles optimizes electrodiagnostic yield, thus possibly minimizing test duration and patient discomfort. Muscle Nerve 56: 36-44, 2017. © 2016 Wiley Periodicals, Inc.

  6. Assessment of muscle fatigue using electromygraphm sensing

    Science.gov (United States)

    Helmi, Muhammad Hazimin Bin; Ping, Chew Sue; Ishak, Nur Elliza Binti; Saad, Mohd Alimi Bin Mohd; Mokhtar, Anis Shahida Niza Binti

    2017-08-01

    Muscle fatigue is condition of muscle decline in ability after undergoing any physical activity. Observation of the muscle condition of an athlete during training is crucial to prevent or minimize injury and able to achieve optimum performance in actual competition. The aim of this project is to develop a muscle monitoring system to detect muscle fatigue in swimming athlete. This device is capable to measure muscle stress level of the swimmer and at the same time provide indication of muscle fatigue level to trainer. Electromyography signal was recorded from the muscle movement while practicing the front crawl stroke repetitively. The time domain data was processed to frequency spectra in order to study the effect of muscle fatigue. The results show that the recorded EMG signal is able to sense muscle fatigue.

  7. Changes in muscle coordination and power output during sprint cycling.

    Science.gov (United States)

    O'Bryan, Steven J; Brown, Nicholas A T; Billaut, François; Rouffet, David M

    2014-07-25

    This study investigated the changes in muscle coordination associated to power output decrease during a 30-s isokinetic (120rpm) cycling sprint. Modifications in EMG amplitude and onset/offset were investigated from eight muscles [gluteus maximus (EMGGMAX), vastus lateralis and medialis obliquus (EMGVAS), medial and lateral gastrocnemius (EMGGAS), rectus femoris (EMGRF), biceps femoris and semitendinosus (EMGHAM)]. Changes in co-activation of four muscle pairs (CAIGMAX/GAS, CAIVAS/GAS, CAIVAS/HAM and CAIGMAX/RF) were also calculated. Substantial power reduction (60±6%) was accompanied by a decrease in EMG amplitude for all muscles other than HAM, with the greatest deficit identified for EMGRF (31±16%) and EMGGAS (20±14%). GASonset, HAMonset and GMAXonset shifted later in the pedalling cycle and the EMG offsets of all muscles (except GASoffset) shifted earlier as the sprint progressed (Pfatiguing sprint cycling is accompanied by marked reductions in the EMG activity of bi-articular GAS and RF and co-activation level between GAS and main power producer muscles (GMAX and VAS). The observed changes in RF and GAS EMG activity are likely to result in a redistribution of the joint powers and alterations in the orientation of the pedal forces. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  8. Across-muscle coherence is modulated as a function of wrist posture during two-digit grasping

    Science.gov (United States)

    Jesunathadas, Mark; Laitano, Juan; Hamm, Thomas; Santello, Marco

    2013-01-01

    The purpose of this study was to investigate the extent to which correlated neural inputs, quantified as EMG-EMG coherence across intrinsic and extrinsic hand muscles, varied as a function of wrist angle during a constant force precision grip task. Eight adults (5 males; mean age 29 years) participated in the experiment. Subjects held an object using a two-digit precision grip at a constant force at a flexed, neutral, and extended wrist posture, while the EMG activity from intrinsic and extrinsic hand muscles was recorded through intramuscular fine-wire electrodes. The integral of z-transformed coherence computed across muscles pairs was greatest in the flexed wrist posture and significantly greater than EMG-EMG coherence measured in the neutral and extended wrist posture (P< 0.01 and 0.05, respectively). Furthermore, EMG-EMG coherence did not differ statistically between the extrinsic and intrinsic muscle pairs, even though it tended to be greater for the extrinsic muscle pair (P ≥ 0.063). These findings lend support to the notion of a functional role of correlated neural inputs to hand muscles for the task-dependent coordination of hand muscle activity that is likely mediated by somatosensory feedback. PMID:23958501

  9. Observation and Imitation of Actions Performed by Humans, Androids and Robots: An EMG study

    Directory of Open Access Journals (Sweden)

    Galit eHofree

    2015-06-01

    Full Text Available Understanding others’ actions is essential for functioning in the physical and social world. In the past two decades research has shown that action perception involves the motor system, supporting theories that we understand others’ behavior via embodied motor simulation. Recently, action perception has been facilitated by using well-controlled artificial stimuli, such as robots. One key question this approach enables is what aspects of similarity between the observer and the observed agent facilitate motor simulation? Since humans have evolved among other humans and animals, using artificial stimuli such as robots allows us to probe whether our social perceptual systems are tuned to process other biological entities. In this study, we used humanoid robots with different degrees of humanlikeness in appearance and motion along with electromyography (EMG to measure muscle activity in participants’ arms while they either observed or imitated videos of three agents produce actions with their right arm. The agents were a Human (biological appearance and motion, a Robot (mechanical appearance and motion and an Android (biological appearance, mechanical motion. Right arm muscle activity increased when participants imitated all agents. Increased muscle activation was found also in the stationary arm both during imitation and observation. Furthermore, muscle activity was sensitive to motion dynamics: activity was significantly stronger for imitation of the human than both mechanical agents. There was also a relationship between the dynamics of the muscle activity and motion dynamics in stimuli. Overall our data indicate that motor simulation is not limited to observation and imitation of agents with a biological appearance, but is also found for robots. However we also found sensitivity to human motion in the EMG responses. Combining data from multiple methods allows us to obtain a more complete picture of action understanding and the underlying

  10. Thinking Outside the Button Box: EMG as a Computer Input Device for Psychological Research

    Directory of Open Access Journals (Sweden)

    L. Elizabeth Crawford

    2017-07-01

    Full Text Available Experimental psychology research commonly has participants respond to stimuli by pressing buttons or keys. Standard computer input devices constrain the range of motoric responses participants can make, even as the field advances theory about the importance of the motor system in cognitive and social information processing. Here we describe an inexpensive way to use an electromyographic (EMG signal as a computer input device, enabling participants to control a computer by contracting muscles that are not usually used for that purpose, but which may be theoretically relevant. We tested this approach in a study of facial mimicry, a well-documented phenomenon in which viewing emotional faces elicits automatic activation of corresponding muscles in the face of the viewer. Participants viewed happy and angry faces and were instructed to indicate the emotion on each face as quickly as possible by either furrowing their brow or contracting their cheek. The mapping of motor response to judgment was counterbalanced, so that one block of trials required a congruent mapping (contract brow to respond “angry,” cheek to respond “happy” and the other block required an incongruent mapping (brow for “happy,” cheek for “angry”. EMG sensors placed over the left corrugator supercilii muscle and left zygomaticus major muscle fed readings of muscle activation to a microcontroller, which sent a response to a computer when activation reached a pre-determined threshold. Response times were faster when the motor-response mapping was congruent than when it was incongruent, extending prior studies on facial mimicry. We discuss further applications of the method for research that seeks to expand the range of human-computer interaction beyond the button box.

  11. TIME-OF-DAY EFFECTS ON EMG PARAMETERS DURING THE WINGATE TEST IN BOYS

    Directory of Open Access Journals (Sweden)

    Hichem Souissi

    2012-09-01

    Full Text Available In boys, muscle power and strength fluctuate with time-of-day with morning nadirs and afternoon maximum values. However, the exact underlying mechanisms of this daily variation are not studied yet. Thus, the purpose of this study was to examine the time-of-day effects on electromyographic (EMG parameters changes during a Wingate test in boys. Twenty-two boys performed a 30-s Wingate test (measurement of muscle power and fatigue at 07:00 and 17:00-h on separate days. Surface EMG activity was recorded in the Vastus lateralis, rectus femoris and vastus medialis muscles throughout the test and analyzed over a 5-s span. The root-mean-square (RMS and mean-power-frequency (MPF were calculated. Neuromuscular efficiency (NME was estimated from the ratio of power to RMS. Muscle power (8.22 ± 0.92 vs. 8.75 ± 0.99 W·kg-1 for peak power and 6.96 ± 0. 72 vs. 7.31 ± 0.77 W·kg-1 for mean power, p < 0.001 and fatigue (30.27 ± 7.98 vs. 34.5 ± 10. 15 %, p < 0.05 during the Wingate test increased significantly from morning to evening. Likewise, MPF (102.14 ± 18.15 vs. 92.38 ± 12.39 Hz during the first 5-s, p < 0.001 and NME (4.78 ± 1.7 vs. 3.88 ± 0.79 W·mV-1 during the first 5-s, p < 0.001 were higher in the evening than the morning; but no significant time-of-day effect was noticed for RMS. Taken together, these results suggest that peripheral mechanisms are more likely the cause of the child's diurnal variations of muscle power and fatigue during the Wingate test

  12. Observation and imitation of actions performed by humans, androids, and robots: an EMG study.

    Science.gov (United States)

    Hofree, Galit; Urgen, Burcu A; Winkielman, Piotr; Saygin, Ayse P

    2015-01-01

    Understanding others' actions is essential for functioning in the physical and social world. In the past two decades research has shown that action perception involves the motor system, supporting theories that we understand others' behavior via embodied motor simulation. Recently, empirical approach to action perception has been facilitated by using well-controlled artificial stimuli, such as robots. One broad question this approach can address is what aspects of similarity between the observer and the observed agent facilitate motor simulation. Since humans have evolved among other humans and animals, using artificial stimuli such as robots allows us to probe whether our social perceptual systems are specifically tuned to process other biological entities. In this study, we used humanoid robots with different degrees of human-likeness in appearance and motion along with electromyography (EMG) to measure muscle activity in participants' arms while they either observed or imitated videos of three agents produce actions with their right arm. The agents were a Human (biological appearance and motion), a Robot (mechanical appearance and motion), and an Android (biological appearance and mechanical motion). Right arm muscle activity increased when participants imitated all agents. Increased muscle activation was found also in the stationary arm both during imitation and observation. Furthermore, muscle activity was sensitive to motion dynamics: activity was significantly stronger for imitation of the human than both mechanical agents. There was also a relationship between the dynamics of the muscle activity and motion dynamics in stimuli. Overall our data indicate that motor simulation is not limited to observation and imitation of agents with a biological appearance, but is also found for robots. However we also found sensitivity to human motion in the EMG responses. Combining data from multiple methods allows us to obtain a more complete picture of action

  13. Continuous monitoring of electromyography (EMG), mechanomyography (MMG), sonomyography (SMG) and torque output during ramp and step isometric contractions.

    Science.gov (United States)

    Guo, Jing-Yi; Zheng, Yong-Ping; Xie, Hong-Bo; Chen, Xin

    2010-11-01

    In this study we simultaneously collected ultrasound images, EMG, MMG from the rectus femoris (RF) muscle and torque signal from the leg extensor muscle group of nine male subjects (mean±SD, age=30.7±.4.9 years; body weight=67.0±8.4kg; height=170.4±6.9cm) during step, ramp increasing, and decreasing at three different rates (50%, 25% and 17% MVC/s). The muscle architectural parameters extracted from ultrasound imaging, which reflect muscle contractions, were defined as sonomyography (SMG) in this study. The cross-sectional area (CSA) and aspect ratio between muscle width and thickness (width/thickness) were extracted from ultrasound images. The results showed that the CSA of RF muscles decreased by 7.25±4.07% when muscle torque output changed from 0% to 90% MVC, and the aspect ratio decreased by 41.66±7.96%. The muscle contraction level and SMG data were strongly correlated (R(2)=0.961, P=0.003, for CSA and R(2)=0.999, PEMG RMS in ramp increasing was 8.25±4.00