Compensatory head tilt in upbeating nystagmus.

Upbeating nystagmus has been described in lesions of the posterior fossa. We report a case of upbeating nystagmus accompanying a focal hemorrhagic lesion of the left brachium conjunctivum, the anterior vermis, and the anterior superior left cerebellar hemisphere. The nystagmus was suppressed by a contralateral head tilt. We postulate that in this instance, acquired central nystagmus was inhibited by the otolith-ocular reflex.