Cognitive function and school achievement were studied prospectively over 3 to 4 years in 19 children treated for brain tumors with whole-brain radiotherapy at the Children’s Hospital, Philadelphia, PA. Fourteen children also received adjuvant chemotherapy. A significant drop in IQ was seen among children with non-cortical tumors who received whole-brain radiotherapy with or without chemotherapy and who were treated before age 7. IQ did not decrease significantly in survivors treated after age 7. The IQ fell from a baseline of 104 to 92 at follow-up. 
COMMENT. All children younger than 7 years in this group were receiving special education at follow-up and 50% of the children over 7 years at diagnosis were receiving supplemental educational services. Increased fatiguability could be another reason for the poor school performance in these children.