Analysis of waves of Cervical Spinal Evoked Potentials from Surface Electrodes and Its Clinical Application : Comparative Study with SEP from the Epidural Space

頚部体表面脊髄誘発電位の波形分析と臨床応用 : 硬膜外腔脊髄誘発電位と比較して

Analysis of waves of Cervical Spinal Evoked Potentials from Surface Electrodes and Its Clinical Application : Comparative Study with SEP from the Epidural Space

Creators Omote Kanjiro

Spinal evoked potentials (SEP) recorded from the epidural space have recently been used for evaluating the cervical cord function. However, the method is rather complicated. The present study is to analyse the waves of SEP from the cervical skin surface, and to discuss the possibility of its clinical application, since SEP from the cervical skin can be more safely and more easily recorded than SEP from the epidural space. The subjects used in this study were 30 normal persons and 23 patients with cervical cord lesion. The normal SEP from the surface electrode consisted of 3 negative waves (N_1, N_2, N_3) and 1 positine wave (P_1) whereas SEP from the epidural space consisted of two negative waves (R and N waves). The peak latency of N_2 and N_3 obtained from the surface electrode was equal to peak latency of R and N waves obtained from the epidural space in the same normal subjects. The peak latency of P_1 obtained from the surface electrode was almost equal to the negative peak latency obtained from the brachial plexus after stimulation of the median nerve. The average latencies of N_1, P_1, N_2, N_3 obtained from the surface electrode in normal subjects were 4.90, 5.74, 6.98, 9.08 msec, respectively. In cases with cervical cord lesion if the responses of N_2 and N_3 obtained from the surface electrode are low‐amplituded or absent, the amplitude of R and N wave obtained from the epidural space also tended to be low or absent. It is possible to evaluate the approximate function of both the spinal cord and the roots by recording the SEP from nuchal skin surface, and this method is clinically useful as a screening testing.

[ISSN]0513-1731

[NCID]AN00243156