Noninvasive method for indirectly obtaining autonomic conduction velocity

Peripheral autonomic conduction velocity (ACV) was indirectly measured by analyzing the transient signals resulting from the electrodermal response induced by a Valsalva maneuver, cough, or auditory stimulus recorded noninvasively from the skin surface. Parameters of the transient signals were the latency times, measured by an inflection-point method as the rate of change in time of the skin electrical resistance relative variation, d(SERV)/dt. These derivative signals were simultaneously measured at palm and sole levels on the same side of the body. Latency time was digitally measured, as a delay between the stimulus and the onset of the d(SERV)dt signal. ACV (m/s) was measured by a subtraction method, dividing the difference in hand-foot length by the difference between their measured latency times.<>