EYE-MOVEMENTS IN A FAMILIAL VESTIBULOCEREBELLAR DISORDER

Eye movement abnormalities consisting of poor or absent smooth pursuit and vestibulo-ocular reflex suppression, gaze-paretic and rebound nys tagmus, slow build-up of optokinetic nystagmus, mildly hyperactive ves tibulo-ocular reflex, and a high incidence of strabismus were inherite d in an autosomal dominant fashion in 10 members of a non-consanguineo us English caucasian family. The onset was in early childhood, but was not congenital. In 7 cases there was no tremor, dizziness, consistent ataxia, or other cerebellar signs that are often associated with thes e ocular motor deficits, and apart from strabismus, patients were asym ptomatic. Magnetic resonance imaging of the propositus was normal. Aft er childhood there appears to be no progression, with the oldest affec ted member being 40 years. Two members had been prone to falling in ch ildhood, and one admitted to dizziness when tired. This condition, whi ch is probably benign, has not been previously described and may repre sent a very mild variant of episodic ataxia or a new vestibulocerebell ar syndrome.