Objective
To observe the change of sympathetic skin response (SSR) before and after sympathectomy in patients with idiopathic palmar hyperhidrosis and to find the usefulness of SSR for assessment of the effects of sympathectomy

Method
The SSR was measured in 20 patients with palmar hyperhidrosis and 20 normal control group. Ten days after thoracoscopic sympathectomy, SSR was also measured. A 50∼150 V stimulus was applied over the median nerve and SSR was recorded on bilateral palms and soles with Viking IV (Nicolet Biomedical Ins., U.S.A.). Patient's satisfaction with operation was assessed by questionnaire.

Results
Absent or unstable SSR recordings rate was increased and amplitudes of SSR were significantly decreased in patients with palmar hyperhidrosis compared with control group. After sympathectomy, SSR was absent in all cases on bilateral palms and these results were correlated with clinical improvment. All patients who had undergone surgery showed significant clinical improvement for palmar hyperhidrosis and about 75% of the cases were found to have compensatory sweating from other site of the body.

Conclusion
Abnormal sympathetic nerve system responses were observed in patients with palmar hyperhidrosis. SSR recordings and clinical manifestations were influenced by sysmpathectomy.