The ability of physiological stimuli to generate the sympathetic skin response in human chronic spinal cord injury.

PURPOSE: Sympathetic sudomotor function in chronic spinal cord injury (SCI) has been evaluated to determine if recording the sympathetic skin response (SSR) provides evidence of integrity of the spinal component of the sympathetic pathways.

METHODS

Thirty subjects with chronic SCI and 15 healthy normal subjects were studied. The SSR was elicited using two physiological (auditory and inspiratory gasp) stimuli. In addition, electrical (median and peroneal nerve) stimulation was also performed. Recordings were made from palmar and plantar sites.

RESULTS

Palmar and plantar SSRs could be readily elicited in all control subjects by all stimuli. In the majority of SCI subjects, the presence or absence of the SSR was related to the American Spinal Injury Association (ASIA) impairment scale, which incorporates only motor and sensory assessments. The exceptions indicated preserved (or damaged) sympathetic spinal cord pathways.

CONCLUSIONS

We conclude that the SSR, using either physiological or electrical stimuli, may be a reliable, non-invasive method of determining integrity of sympathetic cholinergic pathways in SCI, with potential for monitoring the effects of intervention and spinal repair.