(DRG) Departments of Neurology, Ophthalmology, Neurosurgery, Otolaryngology - Head & Neck Surgery, Emergency Medicine, and Medicine, The Johns Hopkins School of Medicine, Baltimore, Maryland
Subject
Gaze evoked nystagmus; Rebound nystagmus
Description
When trying to distinguish pathologic gaze-evoked nystagmus from physiologic end point nystagmus, the following features (pathologic gaze-evoked nystagmus (GEN) is seen in this patient with cerebellar hypoplasia) should be sought: 1) GEN persists over more than a few seconds, 2) the amplitude is large, 3) there is a downbeat component to the nystagmus - GEN + downbeat gives a "side pocket" appearance, which is a diagonally-beating nystagmus, 4) GEN persists even when the fixation target is brought back to a ¾ position where the adducting eye can foveate the target, 5) rebound nystagmus is present.
