Video 5.4 Saccadic intrusions (square wave jerks, SWJ) from Neuro-Ophthalmology and Neuro-Otology Textbook

: Seen here are SWJ, which is the most common example of a saccadic intrusion. Here the patient is fixating on the camera, and all of the sudden a saccade takes the eyes off the fixation target, there's a brief intersaccadic interval, and then the eyes return to the target. Therefore, the saccade is the culprit that initiates the movement, rather than the slow phase (which is the culprit with jerk or pendular nystagmus). The intrusions occur quite frequently (many more than would be expected given his age alone), and these prominent SWJ were related to a progressive cerebellar degeneration in his case. - - : Seen here are SWJ, which is the most common example of a saccadic intrusion. Here the patient is fixating on the camera, and all of the sudden a saccade takes the eyes off the fixation target, there's a brief intersaccadic interval, and then the eyes return to the target. Therefore, the saccade is the culprit that initiates the movement, rather than the slow phase (which is the culprit with jerk or pendular nystagmus). The intrusions occur quite frequently (many more than would be expected given his age alone), and these prominent SWJ were related to a progressive cerebellar degeneration in his cas