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目的 :阐明多焦视诱发电位成分是如何从多通道双极记录中得出和进行地形学分析的。并研究不同的视皮层记录位置对多焦视诱发电位的波形、潜伏期 (ms)和振幅(mV)的影响。方法 :采用多通道罗兰电生理系统 (Retiscan ,Wiesbaden/Brandenburg ,Germany)分别测量 5 0位正常人双眼不同视野的多焦视诱发电位 (visualevokedpotential,VEP) (最大的离心率为 30°)。两眼分别给予刺激。伪随机改变的刺激由多通道罗兰系统产生。刺激图形由 6 0个刺激扇形组成 ,每个扇形又含 16个方格 ,8个白色方格 (>130cd/m2 )和8个黑色方格 (<2cd/m2 )。各个刺激单元的刺激翻转由一个伪随机序列控制。电极放置参照双极枕叶电极放置法 ,同时从 4个前 -后矢状中线及 4个水平连线 (横贯枕叶视皮层 )上的皮肤电极上记录视觉诱发电位波形。上述电极可以是正极或负极。结果 :在记录的枕叶皮层区 ,不同记录通道所记录的VEP显示了不同的平均峰潜伏期和振幅值。在矢状中线上记录到的mVEP ,其最大振幅值小于水平线上的记录值。另外 ,刺激视网膜不同部位所诱发的电位在头皮的位置是不同的。结论 :双极枕叶电极在矢状中线上记录到的mVEP与视野地形图记录的有良好的相关性。双极记录位置 :负极在枕骨粗隆 ,而正极在枕骨粗隆矢状轴上 2cm或 4cm?
OBJECTIVE: To elucidate how multifocal visual evoked potentials are derived from multi-channel bipolar recordings and topographically analyzed. The effects of different visual cortex recording positions on the waveform, latency (ms) and amplitude (mV) of multifocal visual evoked potentials were investigated. Methods: Multi-channel Roland electrophysiological system (Retiscan, Wiesbaden / Brandenburg, Germany) was used to measure visualevoked potential (VEP) in different eyes of 50 normal subjects (maximal eccentricity was 30 °). Eyes were given stimulation. Pseudo-randomly varying stimuli are generated by the multichannel Roland system. The stimulus pattern consists of 60 stimulus segments, each with 16 squares, 8 white squares (> 130 cd / m2) and 8 black squares (<2 cd / m2). The stimulus flip of each stimulus is controlled by a pseudo-random sequence. The electrodes were placed in reference to bipolar occipital electrode placement while visual evoked potential waveforms were recorded simultaneously on the skin electrodes on the 4 anterior-posterior sagittal and 4 horizontal lines across the occipital cortex. The above electrode may be a positive electrode or a negative electrode. Results: VEP recorded by different recording channels showed different mean peak latency and amplitude values in the recorded occipital cortical area. The mVEP recorded on the sagittal midline has a maximum amplitude less than the recorded value on the horizontal line. In addition, stimulate the different parts of the retina induced evoked potential in the scalp is different. CONCLUSION: The mVEP recorded on the sagittal midline of bipolar occipital lobe has a good correlation with the visual field topography. Bipolar recording position: the negative pole in the occipital tuberosity, and the positive pole in the occipital tuberosity sagittal axis 2cm or 4cm?