Despite the presence of some voluntary movement, the loss of discrete control impairs functioning of the arm and hand in most hemiparetics. Seventy hemiparetic patients, aged 12 to 78 years, were treated and followed up for six months to three years. Electromyographic activity monitored from dysfunctional primary movers during attempted movement was displayed to the patients as a continuous oscilloscopic trace, reflecting generated muscle activity and allowing its quantification. Coupled with operant conditioning techniques, these displays were modified gradually by reinforcing the patient's effort with auditory feedback during successive approximations to a desired level. Such therapeutic use of electromyographic displays often resulted in a progressive improvement of voluntary movement. More than half the patients acquired and retained purposive movements that meaningfully improved their functional capabilities.
(JAMA 241:814-818, 1979)