Biofeedback is way to enhance a body signal so that one is aware of something that usually occurs at a level below consciousness. An electronic device provides information about a body function (such as heart rate) so that the person using biofeedback can learn to control that function. Biofeedback can help people with arthritis learn to relax their muscles. In this case, an electronic device amplifies the sound of a muscle contracting, so the arthritis patient knows that the muscle is not relaxed.