Sympathetic skin response in carpal tunnel syndrome.

OBJECTIVES

Sudomotor efferent nerve fiber function was studied in carpal tunnel syndrome (CTS).

METHODS

Bilateral median and ulnar sympathetic skin response (SSR) were recorded by sternal stimulation in 22 bilateral and 9 unilateral patients and compared with 21 healthy volunteers.

RESULTS

There was no significant difference between median and ulnar nerve SSR latency, amplitude or area. The median nerve SSR was not different from that of the controls. The median-to-ulnar ratios of SSR parameters were not different in patients and controls. However, the median-to-ulnar ratios of SSR amplitude and area were lower than normal in 3 out of 7 patients with normal nerve conduction whereas this abnormality was found in only 4 out of 46 patients with abnormal nerve conduction.

CONCLUSIONS

Normal SSR results, even in patients with complaints related to sudomotor sympathetic dysfunction, indicate that the SSR does not seem to be a sensitive diagnostic method in CTS.