Brain tumors in children and adolescents--III. Effects of radiation and hormone status on intelligence and on working, associative and serial-order memory.

The effects on intelligence and memory of two post-surgical conditions (radiation treatment, hormone deficiency and supplementation) were explored in 46 children and adolescents with tumors in a variety of brain sites. Verbal intelligence, but not non-verbal intelligence, varied positively with age at radiation treatment. Memory for word meanings was unrelated to either radiation history or to hormone status. Severe deficits in serial position memory occurred with impaired hormone function and an older age at tumor onset. Severe deficits in working memory were associated with a history of radiation and a principal tumor site that involved thalamic/epithalamic brain regions. Radiation treatment and hormone status affect later cognitive function in children and adolescents with brain tumors. Although the greater vulnerability of the verbal intelligence of the younger radiated child and the serial order memory of the child with later tumor onset and hormone disturbances remain to be explained, and although the form of the relationship between radiation and tumor site is not fully understood, the data highlight the need to consider the cognitive consequences of pediatric brain tumors according to a set of markers that include maturational rate, hormone status, radiation history, and principal site of the tumor.