Longitudinal neurodevelopmental evaluation of children with opsoclonus-ataxia

We previously reported on children with opsoclonus-ataxia and found pervasive neurodevelopmental deficits, years after onset, without a clear relationship to treatment modality or timing of treatment. A significant negative correlation of functional status with age at testing raised a question of whether opsoclonus-ataxia is a progressive encephalopathy. We attempted to answer this question with serial testing. In addition, we examined the relationship between clinical course and developmental outcome.

Thirteen of 17 children with opsoclonus-ataxia, all with neuroblastoma, who were previously reported were reevaluated a second time 2 to 4 years after the initial assessment. One subject who lived out of state was partially reevaluated and is included. Five new subjects (2 with neuroblastoma and 3 without) were also enrolled. Each was evaluated twice at a minimum interval of 1 year between sessions. Intercurrent medical course was recorded, emphasizing medication and relapse history. Cognitive, adaptive behavior, academic, speech and language, and motor abilities were assessed.

For the group as a whole, overall standardized, age-adjusted cognitive scores improved. Generally, younger subjects' cognitive and adaptive behavior scores improved more than older subjects. Although all subjects had gains in speech, language, and motor function, some progressed at a slow pace, and in some instances, standard scores dropped. There was a striking influence of clinical course. Although initial presentation was severe and all subjects required high doses of corticosteroids or corticotropin, 5 had a monophasic course and were able to be weaned from treatment without relapses. Fourteen had multiple relapses over the years, generally with reduction of medication or intercurrent illnesses. Of the 5 children with monophasic course, 4 are currently functioning in the average range with a full-scale IQ of > or =90 and age-appropriate academic and adaptive skills.

The results continue to raise concern that opsoclonus-ataxia is sometimes a progressive encephalopathy. A minority of children with opsoclonus-ataxia have a monophasic course. Despite initial severity of symptoms, these children may have a more benign prognosis. For the majority of children with opsoclonus-ataxia, the course includes multiple relapses and requires prolonged treatment. Developmental sequelae are significant in these children with chronic course.