Involuntary single motor unit discharges in spastic muscles during EMG biofeedback training

The apparent involuntary single motor unit discharges observed in many extremity muscles of spastic patients necessitate monitoring raw electromyography during training sessions. The clinician should note that electronic components of some biofeedback instruments may amplify and distort these units so that the feedback, whether by meter or by variable pitch tone, may erroneously be perceived by the patient as a high level of muscle tension.