Cognitive effects of childhood leukemia therapy: a case for four specific deficits.

Prophylactic treatment of the central nervous system (CNS) with cranial irradiation and antineoplastic drugs has made childhood acute lymphoblastic leukemia (ALL) a survivable disease, but at the same time there have been many reports of iatrogenic effects, including deficits in cognitive functioning. Previous research suggests a particular effect on the Freedom from Distractibility factor of the WISC-R, memory, and attention. These particular abilities are tested in a group of 43 ALL survivors, with comparisons against solid tumor as well as sibling controls. The results indicate that four cognitive processes are affected by CNS prophylaxis for ALL: short-term memory, speed of processing, visuomotor coordination, and sequencing ability. Younger children have a more severe speed of processing deficit and children treated with a less rigorous protocol appear to be slightly less affected generally. The specific cognitive deficits found are related to neurological evidence on both theoretical and empirical grounds. Results suggest that children who have received CNS prophylaxis are able to learn, but may be slower to acquire new material and may benefit from bimodal presentation.