Ichikawa T, Yokota T
Department of Neurology, Faculty of Medicine, Tokyo Medical and Dental University.
Bull Tokyo Med Dent Univ. 1994 Mar;41(1):15-22.
To clarify the effect of the change in motoneuronal excitability on the F wave, we studied the persistence, mean size, and minimum latency of the F wave in nine normal subjects while awake and asleep. Recordings were made from the abductor pollicis brevis muscle by stimulating the median nerve at the wrist. The persistence and size of the F wave markedly decreased during sleep, especially in stage REM. The mean size in stage REM was less than 5% of that in stage W in most subjects, and the F wave entirely disappeared in one subject. The minimum latency during sleep was longer than during wakefulness. Prolongation was within 2.0 ms when the persistence was more than 10%. A decrease in the number of motoneurons that elicit the F wave may be the major cause of prolongation. We conclude that the decreased motoneuronal excitability can cause the F wave to disappear without conduction block in the peripheral motor nerve and that the prolongation of the F wave for more than 2 ms provides a marker for proximal conduction delay in the clinical nerve conduction studies.
为阐明运动神经元兴奋性变化对F波的影响，我们研究了9名正常受试者在清醒和睡眠状态下F波的持续时间、平均波幅和最小潜伏期。通过刺激腕部正中神经，记录拇短展肌的电活动。睡眠期间，尤其是快速眼动（REM）期，F波的持续时间和波幅显著降低。大多数受试者REM期的平均波幅小于清醒期的5%，一名受试者的F波完全消失。睡眠时的最小潜伏期比清醒时更长。当F波持续时间超过10%时，潜伏期延长不超过2.0毫秒。引发F波的运动神经元数量减少可能是潜伏期延长的主要原因。我们得出结论，运动神经元兴奋性降低可导致F波在无周围运动神经传导阻滞的情况下消失，且在临床神经传导研究中，F波潜伏期延长超过2毫秒提示近端传导延迟。
