Opsoclonus-myoclonus syndrome (OMS) is an unusual entity of early-childhood onset characterized by variable, irregular, abnormal movements in the trunk and limbs, myoclonus, and chaotic eye movements (opsoclonus). In half of the patients, OMS presents as a paraneoplastic syndrome secondary to tumors of the neural crest (neuroblastoma), but the etiology may be multiple. OMS has been reported to occur in association with viral infections. We describe three patients with clinical features of OMS who developed paroxystic episodes compatible with stimulus-sensitive myoclonus. The presence of these paroxysmal phenomena does not rule out OMS. We suggest that in patients with OMS the presence or absence of stimulus-sensitive myoclonus should be considered to recognize the true prevalence of these particular electroclinical events.

No abstract