Cognitive deficits in long‐term survivors of childhood medulloblastoma and other noncortical tumors: Age‐dependent effects of whole brain radiation

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Abstract
Twenty-four children, aged 1.5–20 yr at diagnosis, with noncortical brain tumors, primarily medulloblastoma, have been followed for 3–4 yr for intellectual status. All the children received craniospinal irradiation, and 19 of 24 received chemotherapy as well. For the group as a whole, Full Scale IQ fell from 104 at baseline to 91 at final follow-up. Children younger than 7 yr at diagnosis showed a significant decrease in IQ as early as year 1, and all changes from baseline to years 3 and 4 were significant. In contrast, children older than 7 yr at diagnosis did not show a significant IQ change from baseline to year 3 or 4. The Spearman correlation coefficient between IQ change and age at diagnosis from baseline to year 4 was 0.57 (P=0.003). This study supports the hypothesis that children treated with whole brain radiation at a younger age have more severe cognitive impairment than those treated at a later age. Limitations in sample size and duration of observations do not permit us to identify whether a true plateau occurs 2–4 yr after irradiation versus a continued progressive decline in intellectual performance. Moreover, we cannot at this time distinguish between a true dementing process versus failure to acquire new cognitive skills at a rate comparable to age-matched peers.