Journal of UOEH
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To evaluate the clinical utility of somatosensory evoked potentials elicited by stimulation of the paraspinal region (PS-SEPs), waveform characteristics and scalp topography were studied in 23 normal controls. PS-SEPs were recorded in 22 patients with spinal lesions, and the relation between the abnormal PS-SEPs and clinico-radiological findings was investigated. 1) The normal control study showed clear waveforms on the scalp elicited by stimulation of the paraspinal region from C7 to the L2 spinous process level, with both bilateral and unilateral stimulation. The latency of PS-SEPs was gradually decreased when stimulation was moved in the caudo-rostral direction. 2) The normal range of spinal conduction time and conduction velocity was wide. ⋯ Generally, abnormal PS-SEPs were found caudal to the clinical sensory level, and a few cases showed abnormal PS-SEPs rostral to the sensory level. The latter might indicate that PS-SEPs detected subclinical sensory disturbance. It was therefore concluded that PS-SEPs are a useful tool for the objective evaluation of sensory disturbance, especially in cases of thoracic lesion, because conventional SEP studies, utilizing non-cephalic references do not provide clear identification of abnormal sensory levels along the thoracic spinal cord.