Tani T, Ushida T, Yamamoto H, Kimura J
Department of Orthopaedic Surgery, Kochi Medical School, Nankoku City, Kochi, Japan.
Electroencephalogr Clin Neurophysiol. 1998 Jul;108(4):325-30. doi: 10.1016/s0168-5597(98)00020-3.
We studied waveform changes associated with a focal conduction block in compression myelopathies.
A total of 26 patients underwent serial intervertebral recording of spinal somatosensory evoked potentials (SSEPs) after epidural stimulation. The site of compression identified by abrupt reduction in size of the negative peak was designated as '0' level with the other levels numbered in order of distance assigning a minus sign caudally.
Considering the response recorded at '-4' as baseline (100%), SSEPs showed a progressive increase rostrally, reaching an average of 154% in amplitude and 216% in area at '-1' followed by an abrupt decline to 32% and 31% at '0'. The incremental change of the negative peak was accompanied by a small reduction in area of the initial positive component to 90% at '-1' considering the value at '-4' as baseline (100%).
The theory of solid angle approximation and the concept of phase cancellation best explain the apparently paradoxical enhancement of the negative peak which characterize typical waveform changes at the site of conduction block.
我们研究了与压迫性脊髓病中局灶性传导阻滞相关的波形变化。
共有26例患者在硬膜外刺激后接受了脊柱体感诱发电位（SSEP）的系列椎间记录。通过负峰大小突然减小确定的压迫部位被指定为“0”水平，其他水平按距离顺序编号，向尾侧方向赋予负号。
以在“-4”记录的反应作为基线（100%），SSEP在向头侧方向显示出逐渐增加，在“-1”处振幅平均达到154%，面积达到216%，随后在“0”处突然下降至32%和31%。负峰的增量变化伴随着初始正成分面积的小幅减小，以“-4”处的值作为基线（100%），在“-1”处降至90%。
立体角近似理论和相位抵消概念最能解释负峰明显矛盾的增强现象，这是传导阻滞部位典型波形变化的特征。
