Sympathetic skin response in acute sensory ataxic neuropathy

Sympathetic skin response (SSR) is a recently described objective method of studying sudomotor sympathetic nerve function and has been studied in a variety of peripheral neuropathies. We report SSR changes in nine patients with acute sensory ataxic neuropathy (ASAN). All had severe sensory and mild motor nerve conduction abnormalities; five had dysautonomia. SSR, elicited by electric shock and cough stimuli, was absent in three patients. Latency was normal in all when SSR was present. Two patients had SSR amplitude of 0.2 mV or less. Absence of SSR did not correlate with dysautonomia, absence of sensory nerve action potential or motor nerve conduction abnormalities. Follow up SSR studies revealed return of absent SSR in one patient over a period of 3 months, despite persistence of ataxia. To our knowledge, this is the first report of SSR changes in ASAN.