Electrophysiologic assessments of the autonomic nervous system include tests of cardiovascular function, sweat test and tests of vasomotor function in which both parasympathetic and sympathetic pathway are evaluated. R-R interval variation(RRIV) among the cardiovascular tests has been shown to be a sensitive test for the detection of parasympathetic dysfunction. But RRIV is infrequently used in clinical practice because it is complex and tie consuming to measure RRIV by conventional EKG equipment. Sympathetic skin response(SSR) test represents the difference in voltage which is determined by the sweat glands between two skin surfaces. SSR reflects only sympathetic function.

In this study we measured RRIV and SSR using routine EMG machine easily. The aim of this study is to describe the method and to establish a normal basis of control values.

Thirty one healthy persons were tested.

The results were as follows:

1) The mean 30:15 ratio was 1.34 and the mean Valsalva ratio was 1.67.

2) The mean E:I ratio and the mean difference between the longest and the shortest R-R interval during deep breathing were 1.42 and 293.23 msec respectively.

3) 30:15 ratio was significantly correlated with Valsalva ratio, E:I ratio and difference between the longest and the shortest R-R interval during deep breathing.

4) The SSR responses were obtained in all subjects. Stimulating the right median nerve at wrist, the mean latency and the mean amplitude were measured at right palm(1.42 sec, 5.33 mV), left palm(1.42 sec, 5.73 mV), right sole(1.96 sec, 3.16 mV), and left sole(1.98 sec, 2.93 mV).

5) Stimulating the right tibial nerve at ankle, the mean latency and the mean amplitude were measured at right palm(1.38 sec, 4.27 mV), left palm(1.37 sec, 4.51 mV), right sole(1.89 sec, 2.29mV), and left sole(1.91 sec, 2.07 mV).

6) The latencies of the SSR recorded at the sole were delayed than those recorded at the palm regardless of the site of stimulation.

7) The amplitude of the SSR recorded at the palm were greater than those recorded at the sole regardless of the site of stimulation.

8) When 5 stimulations were given in right median nerve separated by 2 minutes, five all sequential responses of SSR were obtained and there was no meaningful habituation among each stimulation.