This sliding window experiment is adapted from Samadani et al. (2016) and Samadani et al. (2015) for concussion detection. The participants begin the trial by reading the instructions on the screen. During the trial, a grey mask with a square aperture will cover the entire screen. Behind the mask, a selected video will be played without audio sounds as the aperture slides along the edges of the screen at a fixed speed. The participants are asked to watch the video through this moving aperture. Disconjugate eye movements have been associated with structural brain damage and concussion (Samadani et al. 2015). The aperture should be around 1/8 the size of the screen. Both the aperture size and speed are tunable in the script.