The relationship between long-term neurobehavioral outcome, MRI findings, and late anti-neuronal antibodies was examined in 11 children with neuroblastoma and opsoclonus-myoclonus-ataxia syndrome (OMA) followed for a mean of 7.6 years at the University of California San Francisco, CA. Seven (64%) exhibited only mild neurologic deficits, 2 (18%) had severe deficits, and 2 (18%) had none. Four (36%) had severe cognitive and behavioral deficiences, while 6 (55%) were average and 1 (9%) moderately below average. Brain MRI showed cerebellar atrophy in 5 of 5 tested, whereas antineuronal activity was not detected in the sera of 10 children examined at follow-up. 
COMMENT. Neurologic examination alone is an insufficient indicator of overall function in long-term follow-up of children with neuroblastoma and OMA syndrome. Cognitive tests are the most sensitive indicator of neurobehavioral deficits. Despite residual neurologic abnormalities, some patients have average neurobehavioral function, with continued improvement over time. Late cerebellar atrophy is a common finding and may be related to neuropsychological sequelae; it did not appear to be related to steroid use. The absence of antineuronal activity (ANA) at follow-up negates any role for ANA in continuing neurologic damage in OMA. Behavioral, fine-motor, and academic performance, in addition to neurologic and MRI examinations, should be monitored in the follow-up of children with OMA.