The results of studies of cognitive deficits in long-term survivors of childhood brain tumors are summarized from 31 published reports between 1968-1989 in a review paper from the Division of Child Neurology, The Children’s Hospital, Philadelphia and the Department of Neurology, Children’s National Medical Center, George Washington University, Washington, DC. The increasing use of neuropsychological testing and the development of prospective studies during the first half of the 1980s has shown that from 40% to 100% of long-term survivors have some form of cognitive deficit in various intelligence quotients, visual/perceptual skills, learning abilities, and adaptive behavior. More cognitive deficits are detected the larger the time lapse from treatment to the testing evaluation. Factors predictive of subsequent cognitive deficits included a younger age at diagnosis, radiotherapy, methotrexate chemotherapy, and tumor location. Cognitive deficits occurred more frequently when medulloblastomas adhered to the brain stem, when tumors extended to the hypothalamus, and with hemispheric tumors. Surgery and preoperative hydrocephalus did not appear to modify cognition. 
COMMENT. The quality of life for long-term survivors of childhood brain tumors becomes more important as improvements in treatment are developed. Long-term follow-up with neuropsychological tests is necessary since significant progressive deterioration in cognitive function may be demonstrated as the testing interval following treatment increases.