Downbeat nystagmus is a rhythmic oscillation of the eyes characterized by a slow upward drift followed by a fast downward correction. It occurs when looking straight ahead (the primary position) and typically increases with downward and lateral gaze. Impaired downward pursuit is also usually seen in downbeat nystagmus. Downbeat nystagmus is usually caused by lesions in the cerebellum and dorsal medulla, but it may also be caused by alcohol and some medications.
occurs in arnold chiari malformation , syringomyelia, cva ms . cerebellar degeneration
basshamtube 2 months ago