The Efficacy of Biofeedback Therapy

The effective functioning of any system--electrical, physiological, even so­ cial-is contingent upon the return of information to the system concerning its performance. The loop that provides the system with information about its output is called feedback. All of the homeostatic mechanisms of the body depend upon complicated interrelated feedback mechanisms that serve to stabilize the internal environment. Similarly, all skill learning depends upon knowledge of results. Practice makes perfect only if the individual is aware of how well he performs. An illustration of the significance of feedback involves the acquisition of speech. The child learns to speak by imitating the sounds he hears, and the adequacy of learning depends upon his ability to compare the sound of the words he generates with that of the words generated by those around him. For this reason, individuals who become deaf later in life continue to speak without much difficulty, but children born deaf were, until relatively re­ cently, unable to speak. Only when special techniques were developed by which the deaf person could learn the consequences of his attempts to speak, using visual and tactile cues to make up for his hearing deficit, did it become possible for totally deaf individuals to learn intelligible speech. In a sense, teaching a deaf person to speak is an example of biofeedback. It involves providing alternative feedback channels to compensate for those not available to the individual so that he may acquire volitional control over a specific bodily function. It is therefore not surprising that the earliest applications of biofeedback were in the context of rehabilitation. These included not only teaching the deaf to speak or the blind to see with their