听觉诱发电位N1-P2的强度依赖性

近年来的研究证明听觉诱发电位NI-P2的强度依赖性极有可能受到脑内5-HF抑制性神经元功能的调控,而NI的幅度和潜伏期又可以指示大脑皮层的唤醒水平。这些指标对失眠、头痛或心理障碍患者、或正常老年人的大脑感知状态有较高的参考价值。而在国内,尚无这方面的报道。为了此项研究能向临床拓展,我们在一批正常人中作了测试,旨在确立相关的正常值。八十三位受试者(47位女性和36位男性)被邀参加听觉诱发电位测试,刺激为四种不同强度70,80,90和100dB的clicks.这些chcks是按大约为0.5秒的刺激间隔而随机发放,这种间隔可引发出一个义务性的(obligatory)NI亚成份,而这个义务性NI常常表示受试者的唤醒状态或内在的注意力。P2的潜伏期在最高刺激理量时显著延长。NI-P2的峰对峰幅度和N1,P2的基线对峰的幅度都有显著的刺激强度依赖性,大多数受试者是“放大者”(augmenter)。本研究在幅度/刺激强度函数斜率和N1,P2的潜伏期等多项指标上确立了正常值。

Intensity Dependence of Auditory Evoked N1-P2 Component

Some studies suggest that the intensity dependence of auditory evoked N1-P2 is modu-lated by the 5-HT innervation in the brain,and the amplitude and the latency of Nl indicate the cortical arousal level. These studies might hold true for patients suffering from insomnia, headache or psycho-logical disorders,or contribute to the knowledge of the cognition in normals senale subjects,However,up to date,there is no such reports within China. In order to launch this research in clinics, we conducted the present study in 83 healthy subjects(47 women and 36 men) using clicks at 4 different in-tensities of 70, 80, 90 and l00dB. The clicks were delivered at an interstimulus interval varying randomly around 0.5s, that can elicit an obligatory subcomponent of Nl, which indicates the cortical arousal level or the internal attention trigger. The P2 latency was significantly prolonged at the highest intensity. The intensity dependence of peak-to- peak N1-P2 and of baseline-to-peak Nl and P2 components was pronounced and the majority of subjects were augmenters. This study thus established the normative values of the intensity dependence of auditory evoked Nl- P2 and the amplitudes and laten-cies of Nl and P2.