Five Common Ocular Motor Signs in Cerebellar Disorders - Saccadic Hypermetria, Saccadic Pursuit & VOR Suppression, Gaze-evoked & Rebound Nystagmus
Creator
Daniel R. Gold, DO
Affiliation
(DRG) Departments of Neurology, Ophthalmology, Neurosurgery, Otolaryngology - Head & Neck Surgery, Emergency Medicine, and Medicine, The Johns Hopkins School of Medicine, Baltimore, Maryland
(1) Saccadic hypermetria - an overshoot of the visual target (2) Saccadic smooth pursuit - due to impaired pursuit and low gain, saccades are needed to keep up with the visual target. This gives it a ‘choppy' appearance. (3) Saccadic vestibulo-ocular reflex (VOR) suppression - another manifestation of pursuit impairment, assuming that there is a VOR to suppress - e.g., pursuit will be saccadic but VOR suppression can be normal if there is bilateral vestibular loss and cerebellar disease (cerebellar ataxia, neuropathy, vestibular areflexia syndrome, CANVAS) (4) Gaze-evoked nystagmus - right-beating nystagmus (RBN) in right gaze, left-beating nystagmus (LBN) in left gaze, often seen with vertical gaze-evoked nystagmus as well (5) Rebound nystagmus - RBN in right gaze that transitions to LBN when the patient looks from right to center; LBN to RBN when going from left gaze to center
