Cerebellar Degeneration with Downbeat Nystagmus Provoked by Convergence

Description: This is a 70-yo-woman with a progressive gait disorder, diagnosed with cerebellar ataxia. She displayed typical cerebellar ocular motor signs including gaze-evoked nystagmus, choppy pursuit and VOR suppression, and there was very subtle spontaneous downbeat nystagmus, best appreciated with ophthalmoscopy. When asked to converge, there was clear downbeat nystagmus - this is suggestive of involvement of the utricle-ocular motor pathways centrally. When vertical nystagmus is provoked by convergence, a posterior fossa lesion should be evaluated for. Patients with Wernicke's may also have vertical nystagmus that's only brought with convergence, or their baseline upbeat nystagmus may transition to downbeat with convergence, or vice versa. Number of Figures and legend for each: 0 Number of Videos and legend for each: 1, Patient with idiopathic cerebellar degeneration with downbeat nystagmus brought out by convergence.