Abstract

Four young adult cerebral palsied subjects with a mixture of spasticity and athetosis attended an experimental reflex training program for three one-hour sessions each week over an 18 month period. During each session on-line measures of contraction level and tonic stretch reflex sensitivity from the biceps brachii muscle were shown to the subject on meter displays. Subjects were asked to attempt to control the displays. They were given goals such as: (1) reduce both contraction level and reflex sensitivity displays to zero and (2) increase the contraction level display to 10% of maximum while keeping the reflex sensitivity display at a minimum. Achievement of goals was automatically sensed and used to activate a cassette tape of the subject's favourite music. Contraction level and reflex sensitivity scores were averaged over one-minute intervals to provide a record of long term progress. Elbow-angle and IEMG data were recorded on FM tape for off-line analysis. All four subjects learned to suppress involuntary muscle activity and resting tonic stretch reflex responses. They also learned to produce a two or three-fold variation in action tonic stretch reflex sensitivity while sustaining 10% maximum voluntary contraction. In other words, subjects learned to self-regulate spasm and spasticity at the elbow and to regulate tonic stretch reflex sensitivity independently of contraction level. A visual tracking task requiring voluntary movement about the elbow was employed to assess improvement in functional control of elbow movement. One athetotic subject improved tracking accuracy as a consequence of reducing the amount of involuntary arm movement while the other three subjects showed negligible improvement in functional control.