(DRG) Departments of Neurology, Ophthalmology, Neurosurgery, Otolaryngology - Head & Neck Surgery, Emergency Medicine, and Medicine, The Johns Hopkins School of Medicine, Baltimore, Maryland
This is a 50-yo-man who presented for dizziness and imbalance. His exam demonstrated choppy smooth pursuit and VOR suppression as well as mild gait ataxia. There was mild right-beating nystagmus in right gaze and left-beating nystagmus in left gaze without vertical gaze-evoked nystagmus. Occasionally, the distinction between physiologic end point nystagmus and pathologic gaze-evoked nystagmus can be difficult to make. In his case, the nystagmus was not particularly robust in either direction, but when he was asked to view an eccentric target for 10-20 seconds and then look back to center, there was clear reversal of the direction of nystagmus, known as rebound nystagmus. Normal people may have 1-2 beats of rebound with prolonged eccentric viewing, but in his case, the rebound nystagmus was quite significant - when this is seen, the examiner can feel confident that the nystagmus seen in eccentric gaze is pathologic (due to cerebellar>brainstem pathology). Number of Videos and legend for each: 1, Patient demonstrating rebound nystagmus after prolonged eccentric viewing
