The Influence of Skin Temperature on Latency and Amplitude of the Sympathetic Skin Response(SSR) in Normal Subjects

J Korean Assoc EMG Electrodiagn Med 1999;1(2):201-206.
Published online May 9, 1999.

Abstract

Objectives : This study was designed to assess the influence of skin temperature on sympathetic skin response(SSR) latency and amplitude, and to determine the relative roles of unmyelinated postganglionic sympathetic C fibers and neuroglandular junctions in the modification of these SSR parameters. Methods : We studied the influence of skin temperature on latency and amplitude of the SSR in 20 normal subjects. SSRs were recorded from right palm and sole after stimulation of left median nerve at wrist. To determine the effect of skin temperature on SSR, we were examined SSR after cooling of right upper extremity, right lower extremity and left upper extremity. To determine the relative roles of unmyelinated postganglionic C fiber and neuroglandular junctions, we were examined SSRs after cooling of the right upper arm except hand and the right hand only. Results : At low temperature, the SSR latency was prolonged(p<0.05) and the amplitude was decreased(p>0.05). Latency and amplitude were linearly correlated with skin temperature. With regard to the skin temperature of the upper extremity, a temperature correction factor of 0.0515 sec/℃ was calculated for latency. In lower extremity, a temperature correction factor of 0.0486 sec/℃ was calculated for latency. Conclusion : The latency was prolonged after cooling of skin temperature. But, no significant change in amplitude after cooling. The latency was similarly prolonged after cooling of the upper arm except hand and the hand only. This suggests that not only the postganglionic sympathetic C fibers, but also the neuroglandular junction were responsible for latency modifications. We conclude that skin temperature is a mandatory measurement in the study of the SSR.

Key Words: Sympathetic skin response, Skin temperature