[Clinical study on short latency somatosensory evoked potentials for cervical myelopathy]

The purpose of this study was to examine the clinical value of S-SEP (short latency somatosensory evoked potentials) as a routine test of spinal cord function. On the basis of a preliminary study determining the optimal recording conditions in normal individuals, S-SEP measurement was carried out in patients with cervical myelopathy to examine its diagnostic value for spinal cord lesions. In these patients, the best recordings of N9, N11, and N13 were obtained from the cervical spinous processes with linked ear reference (A1 + A2). In severe myelopathy, the N11-N13 interpeak latency was prolonged. Those with impaired bladder function or decreased deep sensation showed a prolonged N9-N13 interpeak latency. In cases of C3-4 and C4-5 lesions, the N9-N13 and N9-P14 interpeak latencies were significantly more prolonged than in those with C5-6 lesions. The interpeak latencies from P14 to N9 and N11 gradually became shorter postoperatively.