Sensory feedback therapy in patients with brain insult.

Brain insults, regardless of etiology, may disrupt the CNS servosystems concerned with patterned voluntary movements and result in disorders of such movement. To aid functional recovery, we applied in these patients oscilloscopic display of digitally integrated EMG, monitored from malfunctioning primary movers, during attempted execution of movement (sensory feedback therapy). Such display provided the patient with an immediate and continuous visual feedback loop reflecting the events underlying the movement and occuring in the monitored muscle (force, displacement and rate). This information is essential for motor control of patterned voluntary movement. Coupled with auditory reward for optimal performance, such feedback also assumed reinforcing qualities and motivated the patient to execute voluntary movements with progressive improvement. Sixty patients with longstanding CNS insult, resulting in motor impairment, were treated and followed for periods of four months to four years. One half of these patients learned and retained voluntary movements that significantly improved their functional capabilities. Temporary substitution of feedback information about fundamental events in dysfunctional muscles can apparently be of lasting value in treatment of some patients with brain insult.

EMG feedback therapy: review of treatment of 114 patients.

Advances in the understanding of the relationship of proprioceptive (kinesthetic) feedback to motor physiology have prompted the study of therapeutic effects of audiovisual displays of EMG activity. Patients with various manifestations of disturbed neuromotor control were studied prospectively for three years. This group included 114 patients with hemiparesis, torticollis, dystonia, and spinal cord or peripheral nerve injury. Initially, all but one of these patients had some residual volitional motor activity, which was insufficient for adequate function, and all patients had had conventional therapy with little or no functional recovery. Prior to EMG feedback therapy, the duration of illness was from three months to 35 years. The shaping of a patient's motor responses usually occurred gradually, often over an 8 to 12 week period. This modification was accomplished by feeding processed audio-visual signals back to the patient. These signals were proportional to the degree of activity of the muscles responsible for the defective function. The concept of microvolt-second, as a unit of muscle activity, is introduced and defined. Patterned movements, which were previously defective were observed to improve to varying degrees. Following the initial course of treatment, reinforcement was required by some patients. The mechanisms of improvement after EMG feeback therapy are not well understood; however, some hypotheses are presented. The results of this study indicate that EMG feedback therapy may induce significant functional recovery in patients with disturbed neuromotor control.