Inclusion of Height and Limb Length when Interpreting Sympathetic Skin Response.

It is more than a decade since scientists are making use of sympathetic skin response (SSR) as a clinical and research method to evaluate sympathetic nervous system. A major portion of the efferent pathway of this response is composed of non-myelinated nerves. Thus, the latency of the response may be significantly different in normal individuals with different height and limb lengths. This study was designed to investigate the effect of these parameters on the SSR results. We measured the height and limb length of 65 normal individuals with different heights (divided into 3 groups of height ≤150 cm, 150-170 cm, and ≥170 cm). The participants had neither peripheral nor central neuropathy. They also had none of the exclusion criteria. Then, they underwent SSR testing of both palms and soles. The correlation between the height and limb length in relation to SSR parameters (latency and amplitude) was analyzed statistically by Pearson's correlation. No significant correlation was detected between the height and limb length and the SSR amplitude. However, the results showed significant correlation between SSR latency recorded from all four sites (both palms and soles) and the height of participants. Furthermore, there was a significant correlation between SSR latency recorded from any limb and the length of that limb. Regarding the significant effect of the height and limb length on the SSR latency, both the height and limb length should be considered when interpreting the results of SSR.

Sympathetic skin response in electrical burn injury.

BACKGROUND: Electrical burn has been reported to be highly associated with peripheral neuropathy. This study was designed to evaluate the sympathetic skin response (SSR) of electrical burn patients to determine whether the sympathetic nervous system is involved in these patients. MATERIALS AND METHODS: The sympathetic skin response of 28 patients, suffering from electrical burn injury (divided into two groups of high voltage and low voltage exposure) was compared with that of 28 matched subjects, who had never experienced electrical burn. Bilateral palmar and plantar latency and amplitude of SSR were recorded in response to Median and Tibial nerve electrical stimulation. RESULTS: SSR in all recording sites of the electrical burn patients compared showed significantly more prolonged latencies and reduced amplitudes, with their counterparts in the control group with no significant difference between the high voltage and low voltage electrical burns. There was no significant difference in SSR latency, between the entry and exit sites of the electrical current. The SSR amplitude however, showed more reduction in right hand than the left one, in whom the electrical current had entered the body from the right hand. The time lapse between the electrical burn and the SSR study was shown to play no role in the results. DISCUSSION: Increased SSR latency in electrical burn injury may be a sign of autonomic nervous system involvement, through systemic responses to electrical burn.