The Usefulness of Sympathetic Skin Response at Big Toe in Diagnosis of Diabetic Polyneuropathy

J Korean Assoc EMG Electrodiagn Med 2006;8(2):91-96.
Published online May 10, 2006.

Abstract

Objectives: The aim of this study was to determine whether the sympathetic skin responses (SSR) recorded from the big toe are more useful than conventional nerve conduction study in the diagnosis of diabetic neuropathy. Methods: We recorded big toe SSR (SSRBT) and plantar SSR (SSRP) in 53 diabetic patients and 40 agematched normal controls. For SSRP, surface electrodes were attached on the sole (G1) and dorsum of foot (G2). For SSRBT, surface electrodes were attached on the toe-tip (distal phalanx, G1) and the dorsum of the proximal phalanx of the big toe (G2). Peak to peak SSR amplitude of the response with the largest amplitude was measured. A deep inspiration was used as a stimulus. Results: All of the patients and control subjects were assessed by routine nerve conduction study and SSR (SSRBT & SSRP). the sensitivity was 43.39% for conventional nerve conduction study, 37.74% for SSRP, and 68.15% for SSRBT. 75.49% of our patients showed abnormal results in any of three methods. Conclusion: For detecting diabetic polyneuropathy, SSRBT is more useful than routine nerve conduction study or conventional SSRP. Therefore, SSRBT might be better to be included in the electrophysiological investigation of diabetic polyneuropathy.

Key Words: Sympathetic skin response, Diabetic neuropathy, Big toe