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Results for “electromyography feedback”

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At least 307 records · Page 17Linked to original sources
PubMed2001

Influence of methodological parameters on human jaw-stretch reflexes.

The influence of methodological parameters and experimental conditions on the human jaw-stretch reflex was studied in healthy subjects in order to develop a reliable tool for investigation of the excitability of motoneuron pool. Short-latency excitatory reflex responses were evoked by a custom-made stretch device with the subjects biting on a jaw-bar with their front teeth. The displacement and ramp time of the stretches were accurately controlled and automatically triggered by a computer. The reflex responses were measured in the surface electromyogram (EMG) of the masseter and anterior temporalis muscles with online monitoring of the clenching level. The peak-to-peak amplitude of the jaw-stretch reflex was shown to be proportional to the level of EMG activity during isometric contractions, to increase proportionally with increasing stretch displacement at a given ramp time, and to decrease proportionally with increasing ramp time at a given stretch displacement. There were no significant differences in the reflex amplitude between repeated recordings within one session or between different sessions. Local anesthetic around the lower incisors as well as the upper incisors had no significant influence on the reflex amplitude. However, different biting positions on the bars of the stretch device significantly influenced the amplitude of the stretch reflex.

Adult↗
PubMed2002

Task-related electromyographic spectral changes in the human masseter and temporalis muscles.

The masticatory muscles differ in their fiber type composition. It can therefore be expected that their electromyographic (EMG) power spectra will differ during the performance of different bite force tasks. In the present study, surface EMG activity was picked up from the masseter and from the anterior and posterior temporalis muscles of nine adult subjects. At a bite force level as low as 25 N, the mean power frequency (MPF) values of the posterior temporalis were significantly lower than those of the masseter and anterior temporalis. The MPF values of the masseter muscles decreased with an increase of bite force magnitude, whereas the MPF values of the anterior and posterior temporalis did not change significantly. The MPF values were significantly influenced by the direction of bite force. The observed changes of MPF are possibly related to the recruitment of different fiber types, and support the concept that the masticatory muscles behave heterogeneously.

Adult↗
PubMed2004

A breed apart.

Explore the source record for details and available documents.

Altitude↗
PubMed2003

Muscle endurance and power spectrum of the triceps brachii in wheelchair marathon racers with paraplegia.

OBJECTIVE: To investigate differences in triceps brachii endurance and electrical activity between elite marathon and recreational wheelchair athletes with paraplegia. DESIGN AND METHODS: Nine male elite wheelchair athletes between 20 and 46 years of age (average 29.0 +/- 8.2 years) with complete (ASIA-A) T4-L1 paraplegia were compared to a group of six male height- and weight-matched recreational wheelchair athletes with similar ages and injuries. Right triceps brachii maximum voluntary contraction (MVC), as well as the duration of the ability to maintain a 50% MVC were determined for all subjects. Median frequency (MF) and mean power frequency (MPF) were evaluated with fast Fourier transform spectrum analysis. MF and MPF rates of change were calculated and compared with the Student's t-test. SETTING: : Department of Rehabilitation Medicine, University of Occupational and Environmental Health, Japan. RESULTS: Right triceps brachii MVCs of the marathoners (42.4 +/- 8.8 N m (range 33-55 N m)) and recreational athletes (41.6 +/- 9.3 N m (range 32-56 N m)) did not differ significantly (P = 0.63). Endurance, however, did. All of the athletes, but none of the control subjects, were able to maintain a 50% MVC contraction of the right triceps brachii for 2 min (the average contraction duration in the latter group was 75.5+/-16.2 s). MF and MPF of the triceps brachii decreased linearly in both groups, but the slopes in the marathoners (-8.9 +/- 4.6 (-3.8 to -16.4) and -9.7 +/- 4.6 (-4.0 to -17.2)%/min, respectively) were statistically less steep than those in the recreational athletes (-22.3 +/- 8.2 (-9.6 to -31.4) and -21.2 +/- 6.4 (-11.4 to -28.6)%/min, respectively). CONCLUSION: Elite marathoners and active wheelchair users have similar triceps brachii strength. The marathoner's triceps brachii, however, display a significantly improved endurance and a slower decline of MF and MPF with time than do those of their recreational athlete control group.

Adult↗
PubMed2006

Stuttering treatment research 1970-2005: I. Systematic review incorporating trial quality assessment of behavioral, cognitive, and related approaches.

PURPOSE: To complete a systematic review, with trial quality assessment, of published research about behavioral, cognitive, and related treatments for developmental stuttering. Goals included the identification of treatment recommendations and research needs based on the available high-quality evidence about stuttering treatment for preschoolers, school-age children, adolescents, and adults. METHOD: Multiple readers reviewed 162 articles published between 1970 and 2005, using a written data extraction instrument developed as a synthesis of existing standards and recommendations. Articles were then assessed using 5 methodological criteria and 4 outcomes criteria, also developed from previously published recommendations. RESULTS: Analyses found 39 articles that met at least 4 of the 5 methodological criteria and were considered to have met a trial quality inclusion criterion for the purposes of this review. Analysis of those articles identified a range of stuttering treatments that met speech-related and/or social, emotional, or cognitive outcomes criteria. CONCLUSIONS: Review of studies that met the trial quality inclusion criterion established for this review suggested that response-contingent principles are the predominant feature of the most powerful treatment procedures for young children who stutter. The most powerful treatments for adults, with respect to both speech outcomes and social, emotional, or cognitive outcomes, appear to combine variants of prolonged speech, self-management, response contingencies, and other infrastructural variables. Other specific clinical recommendations for each age group are provided, as are suggestions for future research.

Acupuncture↗
PubMed2002

Voluntary and reflex control of the human temporalis muscle.

Electromyographic recordings (EMGs) were made in 10 human subjects from the anterior and posterior parts of the temporalis muscle using skin surface electrodes. The activities produced by voluntary maximal clenching tasks and the reflex responses to electrical stimulation of the muco-gingival junction were studied. In most subjects, maximum activity in both parts of the muscle occurred when clenching in the intercuspal position (anterior temporalis: 7 of 10 subjects; posterior temporalis: 9 of 10 subjects). Clenching maximally in the retruded position usually resulted in less activity; when this activity was expressed as a percentage of the maximum achieved by each subject for that part of the muscle, the median values were: anterior temporalis, 68% and posterior temporalis, 79%. Clenching in the protruded position produced little or no activity (median values: anterior temporalis, 3%; posterior temporalis, 5%). There were no significant differences between the EMG activities of the anterior and posterior parts of the muscle during these tasks when the activities were normalized to the maximum achieved in each part of the muscle. Application of electrical stimuli at the muco-gingival junction (upper incisor region) produced reflex inhibitions and excitations in both parts of the muscle. There were no significant differences in the thresholds of these reflexes between the anterior and posterior parts of the muscle. Furthermore, there was little difference between the two parts of the muscle in terms of the latencies, durations and magnitudes of the responses. Thus the results of the study suggest that there are similar neural control mechanisms for the anterior and posterior parts of the temporalis muscle despite the common view that these parts of the muscle have different functions.

Adult↗
PubMedDate not supplied

Myoelectric control of a computer animated hand: a new concept based on the combined use of a tree-structured artificial neural network and a data glove.

This paper proposes a new learning set-up in the field of control systems for multifunctional hand prostheses. Two male subjects with a traumatic one-hand amputation performed simultaneous symmetric movements with the healthy and the phantom hand. A data glove on the healthy hand was used as a reference to train the system to perform natural movements. Instead of a physical prosthesis with limited degrees of freedom, a virtual (computer-animated) hand was used as the target tool. Both subjects successfully performed seven different motoric actions with the fingers and wrist. To reduce the training time for the system, a tree-structured, self-organizing, artificial neural network was designed. The training time never exceeded 30 seconds for any of the configurations used, which is three to four times faster than most currently used artificial neural network (ANN) architectures.

Amputees↗
PubMed2004

A proprioception based regulation model to estimate the trunk muscle forces.

Evaluation of loads acting on the spine requires the knowledge of the muscular forces acting on it, but muscles redundancy necessitates developing a muscle forces attribution strategy. Optimisation, EMG, or hybrid models allow evaluating muscle force patterns, yielding a unique muscular arrangement or/and requiring EMG data collection. This paper presents a regulation model of the trunk muscles based on a proprioception hypothesis, which searches to avoid the spinal joint overloading. The model is also compared to other existing models for evaluation. Compared to an optimisation model, the proposed alternative muscle pattern yielded a significant spine postero-anterior shear decrease. Compared to a model based on combination of optimisation criteria, present model better fits muscle activation observed using EMG (38% improvement). Such results suggest that the proposed model, based on regulation of all spinal components, may be more relevant from a physiologic point of view.

Abdomen↗
PubMed1983

Effect of electromyographic biofeedback on an isometric strengthening program.

An evaluation was carried out of the strength gains after a 19-day training program that consisted of isometric exercise coupled with electromyographic biofeedback to the knee extensor muscles. The subjects were 30 female undergraduate students who were randomly assigned to one of three groups. The experimental group performed isometric exercise and received electromyographic biofeedback, another group performed isometric exercise without receiving biofeedback, and the control group performed no exercises other than the pretest and posttest. The combination of biofeedback and isometric exercise was shown to produce greater gains in peak torque than isometric exercise alone over a 19-day training period. The authors believe that this study may provide a strong rationale for the clinical use of biofeedback.

Adult↗
PubMed1985

Effects of mental practice on balance in elderly women.

This experimental field study examined the potential usefulness of mental practice for improving physical performance in health care. Ideokinetic facilitation, which involves the use of idealized visual and kinesthetic mental images, was used as mental practice. Thirty-six women over the age of 70 were assigned to one of three intervention groups: Group A, nonsense; Group B, relaxation; or Group C, ideokinetic facilitation. Baseline and final measures of one-legged balance time were compared after a three-day intervention period. Results showed significant improvement between baseline and final measures within Group C only (t = 2.64, p less than or equal to .05). The improvement in Group C, however, was not significantly more than the improvement in Groups A and B. This study suggests that mental practice of a physical task can improve performance and may be of use to the physical therapy clinician.

Aged↗
PubMed1993

Electromyography: some methodological problems and issues.

The purpose of this review is to discuss electromyography (EMG) and some of the problems and issues that are encountered during the recording and interpretation of EMG data. Recordings of electrical activity of muscles can be contaminated by interference from the electrical supply, mechanical artifacts, stimulus artifacts, and activity of other muscles. The advantages and disadvantages of surface electromyography and intramuscular EMG are compared and contrasted, and precautions to be taken when recording and interpreting these data are described. Surface electromyography is usually more susceptible to artifacts than is intramuscular EMG. It is possible, however, to make useful recordings with the surface electrodes from large superficial muscles if appropriate precautions are observed. Intramuscular electrodes, on the other hand, may be preferred for recording the activity from small peripheral muscles or muscles located deep within the body.

Artifacts↗