Hypoplasia of hemispheric white matter, peculiar pallidal changes and dysplastic inferior olives in a child with psychomotor retardation.

A 25-month-old child with nonprogressive psychomotor retardation is described. Symmetrical hypoplasia of hemispheric white matter with an apparently intact cortex was a major finding. Maternal trauma to abdomen at 25 weeks of gestation was probably implicated in precipitating the condition. Also, changes resembling hypertrophy of the inferior olives were found in the pallida and were associated with dysplasia of the inferior olivary nuclei. There were other findings to suggest that the pallidal and olivary changes were secondary to deafferentation.