RR interval variation and the sympathetic skin response in the assessment of autonomic function in peripheral neuropathy
B. T. Shahani, T. J. Day, D. Cros, N. Khalil and C. S. Kneebone
Clinical Neurophysiology Laboratories, Massachusetts General Hospital, Boston 02114.
The diagnostic value of two simple tests of autonomic function, the RR
interval variation and the sympathetic skin response, was evaluated
relative to symptoms of dysautonomia in 53 patients with peripheral
neuropathy. Of 22 patients with peripheral neuropathy and clinical
dysautonomia, 15 showed abnormal results on both tests, and 7 had abnormal
results on one test only. In none of the patients with dysautonomia were
both tests' results normal. Conversely, all 15 patients with abnormal
results of both sympathetic skin response and RR interval variation had
symptoms of dysautonomia, while 7 of 15 patients with abnormalities limited
to one test had such symptoms. No patient with normal results on both tests
had clinical dysautonomia. These data indicate that RR interval variation
and sympathetic skin response, both of which can easily be performed in the
electromyography laboratory, are helpful in combination in the assessment
of autonomic function in peripheral neuropathies.
