CHARACTERIZING NEUROCOGNITIVE AND BEHAVIORAL FUNCTIONING IN PEDIATRIC OPSOCLONUS-MYOCLONUS SYNDROME (OMS)

Objectives: Opsoclonus-myoclonus syndrome (OMS) has been identified as occuring most often in children with neuroblastomas; however, it has also been seen in children with no known neurotumors. In such cases, it is now believed that OMS reflects an aggressive autoimmune response that preferentially impacts neurological functioning, specifically the cerebellum, brainstem, and subcortex. While the etiology and neurological course of OMS have been reasonably documented in the literature, questions remain as to the impact this syndrome may have on developing cognitive and behavioral functioning. Even following intensive treatment, some children show a pattern of cognitive decline, behavioral dyscontrol, and vulnerability to conduct and anxiety disorders. Characterizing the typical versus atypical pattern of development in youngsters with OMS is believed to be an important area of research concerning this sometimes disabling disorder.

Methods: Five children diagnosed with OMS who were aggressively treated with ACTH and IVIG were referred for neuropsychological and behavioral assessment, in order to better document and ascertain their pattern of difficulties and to identify more effective intervention strategies. Two of these children, both females who were first diagnosed at late toddlerhood with OMS, were evaluated yearly over a three year period; the additional three youngsters (two males and one female) were seen one time for evaluation. This report describes convergent and divergent findings regarding the development of neurocognitive and behavioral skill in these children, including verbal and visual processing, visuospatial and visuoconstructional abilities, fine and groß motor control, attention and executive functioning, memory, and emotional regulation.

Results: Across all of the five children evaluated, results highlight significant difficulties with attention, concentration, impulsivity, social relatedness and understanding of social cues, fine motor control, and integration of multimodal information. Executive concerns were predominant, across variable presentations of intellectual skill. Behavioral difficulties appeared to correlate most strongly with deficits in executive and attentional capacity in this group of youngsters. Conclusion: It appears that children, both with typical and atypical presentations of OMS, show a consistent pattern of neurocognitive deficit, with predominant deficits in executive, attentional, and behavioral regulatory skill development. This pattern is consistent across levels of intervention as well, suggesting that neurocognitive and behavioral development are at risk in OMS. Implications for assessment and intervention are discussed.