“Biofeedback is the process of gaining greater awareness of many
physiological functions primarily using instruments that provide information on the activity of those same systems, with a goal of being able to manipulate them at will.
[1][2] Some of the processes that can be controlled include
brainwaves,
muscle tone,
skin conductance,
heart rate and
pain perception.
[3]
Biofeedback may be used to improve health, performance, and the physiological changes that often occur in conjunction with changes to thoughts, emotions, and behavior. Eventually, these changes may be maintained without the use of extra equipment, for no equipment is necessarily required to practice biofeedback.
[2]
In skin conductance, an electrodermograph imposes an imperceptible current across the skin and measures how easily it travels through the skin. When anxiety raises the level of sweat in a sweat duct, conductance increases. Skin conductance is measured in microsiemens (millionths of a
siemens). In skin potential, a therapist places an active electrode over an active site (e.g., the palmar surface of the hand) and a reference electrode over a relatively inactive site (e.g., forearm). Skin potential is the voltage that develops between eccrine sweat glands and internal tissues and is measured in millivolts (thousandths of a volt). In skin resistance, also called
galvanic skin response (GSR), an electrodermograph imposes a current across the skin and measures the amount of opposition it encounters. Skin resistance is measured in kΩ (thousands of ohms).
[25]” taken from WIKIPEDIA
Biofeedback therapists use electrodermal biofeedback when treating
anxiety disorders,
hyperhidrosis (excessive sweating), and stress.
[21][26] Electrodermal biofeedback is used as an adjunct to psychotherapy to increase client awareness of their emotions.
[27][28] In addition, electrodermal measures have long served as one of the central tools in
polygraphy (lie detection) because they reflect changes in anxiety or emotional activation.