The value of sympathetic skin response for early diagnosis of diabetic neuropathy

Objective To study the association between sympathetic skin response (SSR) and diabetic neuropathy,and explore its use as the objective base for its early diagnosis. Methods The latencies and amplitudes of the initiation,waves N and P in SSR of the extremities in 80 diabetic patients and 30 healthy controls were determined using electrophysiological measurements. Results The latencies of the initiation,waves N and P of SSR test were prolonged significantly in the diabetic patients as compared to the controls ( P 0.001),while there was no significant difference in the amplitudes ( P 0.05). All but two patients (97.5%) demonstrated abnormal SSR in at least one limb. Seven patients (8.8%) had no responses in SSR in both the feet and hands. The frequency of abnormality in the latency of initiation and waves N and P was 86.9%(139/160)in the upper limbs,and 89.4%(143/160)in the lower limbs. Conclusions The SSR can detect the early dysfunction of the small sympathetic fibers in diabetes millitus and may be a useful electrophysiologic testing for the early diagnosis of diabetic neuropathy.