Non-invasive assessment of peripheral dysfunction of the autonomic nervous system

The functional status of the autonomic nervous system was indirectly and noninvasively assessed by recording the skin electrical relative resistance variation (SERV). The advantages of this approach are: (1) it is possible to record simultaneously on two to four channels the evoked electrodermal response to a psychic or a sensorial stimulus; (2) a self-balancing system allows the recording of the relative variation of the electric parameter, i.e. its variation with time; (3) a precise determination of the amplitude (mm) of the evoked response is possible; and (4) the reference of the anatomic pathway of the signal to the latency time of the evoked response permits calculation of the autonomic conduction velocity.