Hoffmann Michael B, Seufert Petra S, Bach Michael
Visual Processing Laboratory, Universitäts-Augenklinik, Leipziger Str. 44, 39120 Magdeburg, Germany.
Clin Neurophysiol. 2004 Nov;115(11):2659-65. doi: 10.1016/j.clinph.2004.06.003.
The aim of this study is to quantify and compare the effects of simulated horizontal nystagmus on pattern-reversal and pattern-onset visual evoked potentials (VEPs).
In eight visually normal subjects with normal oculomotor behaviour, we monitored eye movements and recorded pattern-reversal and pattern-onset VEPs from occipital electrodes. Subjects viewed the stimulus monocularly via a mirror, which was placed close to the eye and driven by a scanner at four different amplitudes (0, 1, 2, and 3 degrees ) with a 4 Hz saw-tooth waveform to simulate horizontal jerk-nystagmus.
Retinal image motion nearly abolished the pattern-reversal VEPs (maximal reduction by 85%; mean reduction by 72%, P<0.001), while there was a non-significant reduction (mean reduction by 15%) of the pattern-onset VEPs.
The differential effect of simulated nystagmus on pattern-reversal and pattern-onset VEPs resembles that reported in studies on nystagmus patients. We conclude that the interaction of retinal image motion with the stimulus is sufficient to explain the reduction of pattern-reversal VEPs in patients with nystagmus and propose simulated nystagmus as a useful tool to test the influence of nystagmus on the efficiency of VEP stimuli.
This study demonstrates how horizontal jerk-nystagmus can be simulated and suggests possible mechanisms by which nystagmus reduces VEP responses.
本研究旨在量化并比较模拟水平性眼球震颤对图形翻转视觉诱发电位（VEP）和图形起始视觉诱发电位的影响。
在8名具有正常眼动行为的视力正常受试者中，我们监测眼动并从枕部电极记录图形翻转和图形起始VEP。受试者通过靠近眼睛放置的镜子单眼观看刺激，镜子由扫描仪以4Hz的锯齿波形驱动，有四种不同幅度（0、1、2和3度）以模拟水平急跳性眼球震颤。
视网膜图像运动几乎消除了图形翻转VEP（最大降低85%；平均降低72%，P<0.001），而图形起始VEP有不显著的降低（平均降低15%）。
模拟眼球震颤对图形翻转和图形起始VEP的不同影响类似于在眼球震颤患者研究中所报道的情况。我们得出结论，视网膜图像运动与刺激的相互作用足以解释眼球震颤患者图形翻转VEP的降低，并提出模拟眼球震颤作为一种有用的工具来测试眼球震颤对VEP刺激效率的影响。
本研究展示了如何模拟水平急跳性眼球震颤，并提出了眼球震颤降低VEP反应的可能机制。
