title: Specific muscle EMG biofeedback for hand dystonia.
abstract: Currently available therapies have only limited success in patients having hand dystonia (writer's cramp). We employed specific muscle EMG biofeedback (audio feedback of the EMG from proximal large muscles of the limb that show abnormally high activity during writing) in 10 of 13 consecutive patients (age, 19-62 years; all males) with a duration of illness from 6 months to 8 years. In three patients, biofeedback was not applicable due to lack of abnormal EMG values. Nine patients showed dystonic posture during writing and had hypertrophy of one or more large muscles of the dominant hand. The remaining four patients showed either involvement of small muscles or muscle wasting. Ten patients were given four or more sessions of EMG audio biofeedback from the proximal large limb muscles, which showed maximum EMG activity. They also practiced writing daily with the relaxed limb for 5 to 10 min. Nine patients showed improvement from 37 to 93% in handwriting, alleviation of discomfort, and pain (assessed on a visual analogue scale). One patient did not show any improvement. Thus EMG biofeedback improved the clinical and electromyographic picture in those patients with hand dystonia who showed EMG overactivity of proximal limb muscles during writing. This specific type of EMG biofeedback appears to be a promising tool for hand dystonia and might also be applied to other types of dystonias.
authors.affiliation: Department of Physiology, All India Institute of Medical Sciences, New Delhi, India. kkdeepak@hotmail.com
authors.forename: K K
authors.initials: KK
authors.lastname: Deepak
authors.forename: M
authors.initials: M
authors.lastname: Behari
mesh_terms: D000328:Adult; D001676:Biofeedback, Psychology; D004421:Dystonia / Q000503:physiopathology / Q000628:therapy*; D004576:Electromyography; D005260:Female; D006225:Hand; D006801:Humans; D008297:Male; D008875:Middle Aged; D009120:Muscle Cramp / Q000503:physiopathology / Q000628:therapy*; D018482:Muscle, Skeletal / Q000503:physiopathology; D010147:Pain Measurement; D014956:Writing