Maruta Jun, Jaw Eugene, Modera Peter, Rajashekar Umesh, Spielman Lisa A, Ghajar Jamshid
Brain Trauma Foundation, 1999 South Bascom Avenue, Suite 1040, Campbell, CA 95008.
Mil Med. 2017 Mar;182(S1):120-123. doi: 10.7205/MILMED-D-16-00093.
Human visual tracking performance is known to be reduced with an increase of the target's speed and oscillation frequency, but changes in brain states following a concussion may alter these frequency responses. The goal of this study was to characterize and compare frequency-dependent smooth pursuit velocity degradation in normal subjects and patients who had chronic postconcussion symptoms, and also examine cases of acutely concussed patients. Eye movements were recorded while subjects tracked a target that moved along a circular trajectory of 10° radius at 0.33, 0.40, or 0.67 Hz. Performance was characterized by the gain of smooth pursuit velocity, with reduced gain indicating reduced performance. The difference between normal and chronic patient groups in the pattern of decrease in the gain of horizontal smooth pursuit velocity as a function of the stimulus frequency reflected patients performing more poorly than normal subjects at 0.4 Hz while both groups performing similarly at 0.33 or 0.67 Hz. The performance of acute patients may represent yet another type of frequency response. The findings suggest that there may be ranges of stimulus frequencies that differentiate the effects of concussion from normal individuals.
众所周知，随着目标速度和振荡频率的增加，人类视觉跟踪性能会降低，但脑震荡后大脑状态的变化可能会改变这些频率响应。本研究的目的是描述和比较正常受试者以及患有慢性脑震荡后症状的患者中频率依赖性平稳跟踪速度的下降情况，并检查急性脑震荡患者的病例。在受试者跟踪沿半径为10°的圆形轨迹以0.33、0.40或0.67赫兹移动的目标时，记录眼球运动。性能通过平稳跟踪速度的增益来表征，增益降低表明性能下降。正常组和慢性患者组在水平平稳跟踪速度增益随刺激频率下降的模式上的差异反映出，在0.4赫兹时患者的表现比正常受试者差，而在0.33或0.67赫兹时两组表现相似。急性患者的表现可能代表了另一种频率响应类型。研究结果表明，可能存在一些刺激频率范围，可以区分脑震荡对个体与正常人的影响。
