Purves A M, Boyd S G
Department of Clinical Neurophysiology, Hospital for Sick Children, London, UK.
Electroencephalogr Clin Neurophysiol. 1993 Mar-Apr;88(2):118-22. doi: 10.1016/0168-5597(93)90062-t.
Cerebral potentials evoked by CO2 laser stimulation were recorded in 22 normal volunteers. Substantial variability in latency, morphology and amplitude of the responses in individual trials was noted, and in some trials no response appeared to be present. Averaging after latency correction and removal of traces without clear responses was compared with conventional time-locked averaging. We found a greater amplitude and more consistent wave form in the former case, and better preservation of amplitude with increasing age and under conditions of impaired attention. Cross-correlation techniques and Minimum Mean Square Error (MMSE) filtering did not assist identification of responses. We conclude that with laser-evoked cerebral potentials visual identification of components is a simple and reliable way of obtaining an improved estimate of the average evoked potential.
在22名正常志愿者中记录了二氧化碳激光刺激诱发的脑电位。在个别试验中，观察到反应的潜伏期、形态和振幅存在很大差异，并且在一些试验中似乎没有出现反应。将潜伏期校正并去除无明显反应的痕迹后进行平均，与传统的时间锁定平均进行比较。我们发现前一种情况下振幅更大，波形更一致，并且随着年龄增长和注意力受损的情况下，振幅保存得更好。互相关技术和最小均方误差（MMSE）滤波无助于识别反应。我们得出结论，对于激光诱发的脑电位，通过视觉识别成分是获得平均诱发电位更好估计值的一种简单可靠的方法。
