Opsoclonus in a patient with cerebellar dysfunction

After two days of malaise, headache, nausea, and vomiting, a 26-year-old ma n suddenly developed opsoclonus and stance and gait ataxia, without myoclon us. Having excluded a paraneoplastic etiology, we assumed that the disorder was probably related to a viral infection. Spontaneous resolution occurred in about two months. Opsoclonus became flutter dysmetria and then resolved . Saccadic eye movement recording disclosed the occurrence of hypermetria, increased velocity, and delayed latency, which also resolved. In this patie nt, the correspondence between clinical and ocular motor abnormality course s suggests a transient cerebellar dysfunction as the possible pathophysiolo gic mechanism for opsoclonus.