Tsuneishi S, Casaer P, Fock J M, Hirano S
Division of Pediatric Neurology, University Hospital Gasthuisberg, Louvain, Belgium.
Electroencephalogr Clin Neurophysiol. 1995 Jul;96(4):291-9. doi: 10.1016/0168-5597(95)00031-m.
To establish normal values for flash visual evoked potentials (VEPs) in the preterm period, we analyzed 356 records from 63 neurologically normal infants (26-35 weeks gestation) followed longitudinally. Using both sleep and drowsy state recording within the same session and a mean of 5.7 weekly recording sessions per infant, we hypothesized that the prominent negative wave (N1) consisted of 2 negative components, N1a (early) and N1b (late). This hypothesis could explain the previously reported variability in VEP indices. With a precise definition of the N1a peak, we were able to establish reference ranges for N1a peak latencies at various postmenstrual ages (PMA) which, unlike those previously reported, are narrow enough to be clinically useful. From a cross-sectional analysis we found that the N1a peak latency decreased with maturation at about 4.6 msec/week between 30 and 40 weeks PMA (P < 0.001). We also analyzed the N1 wave form and demonstrated its developmental maturation during this period. There were significant decreases in the amplitudes of both the N1a and N1b peaks with maturation (P < 0.001), but the decrease of the N1a amplitude was steeper than that of N1b. The N1 wave form changed from a wave in which the early peak (N1a) was higher than the late peak (N1b) into the reverse with N1b higher than N1a. This wave change may be related to developmental processes in the visual system. Longitudinal follow-up revealed that extra-uterine life may accelerate the maturation of the N1 wave form but has no effect on the decrease of the absolute values of peak latencies.
为了建立早产儿闪光视觉诱发电位（VEP）的正常值，我们对63名神经功能正常的婴儿（孕龄26 - 35周）进行了纵向分析，共获得356份记录。在同一次检查中同时使用睡眠和嗜睡状态记录，每个婴儿平均进行5.7次每周记录，我们假设突出的负波（N1）由2个负成分组成，即N1a（早期）和N1b（晚期）。这一假设可以解释先前报道的VEP指标的变异性。通过对N1a峰的精确定义，我们能够建立不同月经后年龄（PMA）时N1a峰潜伏期的参考范围，与先前报道的不同，这些范围足够窄，具有临床实用性。通过横断面分析，我们发现N1a峰潜伏期在30至40周PMA之间随成熟度以约4.6毫秒/周的速度下降（P < 0.001）。我们还分析了N1波形，并展示了其在此期间的发育成熟情况。随着成熟，N1a和N1b峰的振幅均显著下降（P < 0.001），但N1a振幅的下降比N1b更陡峭。N1波形从早期峰值（N1a）高于晚期峰值（N1b）的波形转变为晚期峰值（N1b）高于早期峰值（N1a）的波形。这种波形变化可能与视觉系统的发育过程有关。纵向随访显示，宫外生活可能加速N1波形的成熟，但对峰值潜伏期绝对值的下降没有影响。
