[kcvl]

In practice, virtually all polygraph instruments used for psychophysiological credibility assessment record measures from at least three physiological systems that are controlled by the autonomic nervous system. Recordings are usually made of palmar sweating (commonly known as the galvanic skin response), relative blood pressure (obtained from an inflated cuff on the upper arm), and respiration (obtained from volumetric sensors placed around the chest and/or abdomen). Many instruments will also provide a measure of peripheral blood flow (usually obtained from a photoelectric plethysmograph placed on one of the fingers).

[Quilla]

Thank you. Your reputation for informative posts on FR is legend.