Sympathetic skin response in patients with spinal cord injury.

PURPOSE To assess the effectiveness of sympathetic skin response in evaluating peripheral sympathetic nerve activity of patients with spinal cord injury, and to report on the basic properties of sympathetic skin response. METHODS Sympathetic skin response evoked by electrical stimulation was recorded from the palms and soles of healthy volunteers and patients with spinal cord injury. RESULTS Sympathetic skin response was recorded in 17 healthy volunteers and 14 patients with spinal cord injury. Of the 4 waveforms, the shortest latency was obtained from the palm; the sympathetic skin response was 1.2 to 1.4 ms at all stimulated sites, 1.9 to 2.0 ms at the sole, with a difference of about 0.6 ms between the palm and the sole. None of the patients with spinal cord injury responded at either the upper or lower limbs. In patients with a thoracic cord injury, some responded at the upper limbs but none at the lower limbs; some responded at neither upper nor the lower limbs; and some responded at both upper and lower limbs. The conducting pathway of sympathetic skin response in the spinal cord for the upper limbs descends to the upper thoracic cord (T4-6), and the conducting pathway for the lower limbs departs from the spinal cord at the lower thoracic cord (T9-10). CONCLUSION It appears that sympathetic skin response should be used for the evaluation and morbid investigation of the functional abnormalities of the sympathetic nervous system in patients with spinal cord lesions such as spinal cord injuries, cervical spondylosis, and spinal canal stenosis.