Biofeedback in rehabilitation: a review of principles and practices.

Modern biofeedback is the technique of using electronic equipment to reveal instantaneously to patients and therapists certain physiologic events and to teach the patients to control these otherwise involuntary events by manipulating the displayed signals (usually visual and/or acoustic). Diagnostic EMG and research on the fine control of motor units led to clinical EMG biofeedback. In rehabilitation it has gained a firm place in the treatment of upper motor neuron lesions, particularly in retraining muscles and inducing relaxation of spastic muscles of stroke patients. In cerebral palsy and musculoskeletal disturbances, additional feedback transducers (electrogoniometers, pressure-sensitive and position-sensing devices) are gaining wider use. Spasmodic torticollis has proved to be particularly suitable for behavioral methods of treatment including EMG feedback.