Method
EMG-triggered electrical stimulation was applied to the extensor digitorum communis (EDC) of 8 chronic hemiplegics who showed no functional changes for more than 3 months. Stimulation was started when the amplitude of processed EMG signal from the same muscle exceeded the preset threshold. The therapeutic effect was evaluated by kinesiologic and clinical methods before and after 4 weeks. Quantitative EMG from EDC, excursion of second metacarpophalangeal joint, and functional measurements were used. We also evaluated cognitive and perceptual effect on recovery of arm function.

Results
Subjects treated with EMG-triggered electrical stimulation showed significant gain in amplitude of quantitative EMG and excursion sum during maximal exertion comparing to those of pre-treatment (p＜0.05). There was also an decrease of spasticity after treatment. But functional, perceptual and cognitive outcome were not changed significantly (p＞0.05).

Conclusion
These results suggest that EMG-triggered electrical stimulation might be an effective therapeutic modality to improve motor function of the hemiplegic arm of chronic brain injured patients. (J Korean Acad Rehab Med 2003; 27: 320-328)