A polygraph (translated as 'many writings') is an instrument which measures
and records several body-response variables including blood pressure,
heart rate, respiration and skin-resistance while a series of questions
are being asked, in an attempt to determine the truth about a matter.
At least four items will be attached to the examinee, and those in turn
connect to the polygraph: a blood-pressure cuff on the left arm, a breathing
measurement device at the abdomen, a breathing measurement device at the
chest, and skin-conductance measurement wires on the right hand.