Biofeedback is a technique used to improve the ability to modify involuntary processes consciously. It is frequently used for symptom management in chronic illness and as part of physical therapy for patients with motor dysfunction. The general strategy to biofeedback starts with utilizing non-invasive equipment to take measurements of a chosen physical parameter. The measured parameter is then either displayed directly or transformed into a visual, auditory, or tactile feedback signal. The patient will then practice controlling the feedback signal by consciously adjusting the physical parameter. Because the technique provides another form of feedback in addition to the body’s intrinsic sensory nervous system, it is sometimes called augmented feedback or extrinsic feedback.
Biofeedback divides into two major groups, biomechanical and physiologic, based on the parameter of interest. Biomechanical techniques measure body activity and movement using simple inertial sensors or more complex video motion sensors. Several different modalities serve to measure physiologic activity. Muscle activity measured by electromyography is one of the most common, but other options are cardiac activity measured by heart rate and heart rate variability, breathing activity measured by respiratory rate and depth, and electrodermal activity measured by skin conductance. Forms of biofeedback have been in use in physical therapy for more than 50 years, where it is beneficial in the management of neuromuscular disorders. Biofeedback techniques have shown benefit when used as part of a physical therapy program for people with motor weakness or dysfunction after stroke, after orthopedic surgery, or due to other neuromuscular diseases. These methods are getting better at training for complex task-oriented activities like walking and grasping objects as technology continues to advance.
Aside from neuromuscular retraining, the most common use for biofeedback is to help with chronic symptom management due to anxiety, pain, and urinary and fecal incontinence. These techniques focus on managing the overactive sympathetic response and coordinating muscle activity in gastrointestinal and genitourinary tracts.
Biofeedback techniques are generally regarded as safe and free of side effects. For this reason, they are incorporated into treatment plans despite lacking strong evidence to support their benefits.