Somatosensory evoked potentials (S.E.P.) in slow pathological compression of the spinal cord

Somatosensory evoked potentials (S.E.P.) were used to examine twelve patients who had slow compressive lesions of the spinal cord (ten cases of spondylotic myelopathy, one neurinoma, one metastasis of a vertebral body). 73 per cent of the recordings were found to be abnormally reduced in amplitude, and/or showed prolonged latency times aa regards the primary and secondary complex. Patients with a clinical lesion of the dorsal column showed a clear reduction in amplitude in the recordings (sometimes coupled with slowed latency), especially in the primary complex. Patients with symptoms indicative of an injury to the ventrolateral region of the spinal cord showed tracings with alterations most of all related to the secondary complex. In 76 per cent of cases, the somatosensory evoked potentials were in accordance with the level of the compression, the degree of invalidity, and the clinical picture.