Developmental model relating white matter volume to neurocognitive deficits in pediatric brain tumor survivors.
BACKGROUND
The primary objective of this study was to test the hypothesis that, among survivors of pediatric brain tumors, the association between reduced volumes of normal-appearing white matter (NAWM) and intellectual/academic achievement deficits can be explained by patient problems with memory and attention.


METHODS
Quantitative tissue volumes from magnetic resonance imaging scans and neurocognitive assessments were obtained for 40 long-term survivors of pediatric brain tumors. They were treated with radiotherapy (RT) with or without chemotherapy 2.6-15.3 years earlier (median, 5.7 years) at an age of 1.7-14.8 years (median, 6.5 years). Neurocognitive assessments included standardized tests of intellect (intelligence quotient [IQ]), attention, memory, and academic achievement.


RESULTS
Analyses revealed significant impairments in patients' neurocognitive test performance on all measures. After statistically controlling for age at RT and time from RT, significant associations were found between NAWM volumes and both attentional abilities and IQ, and between attentional abilities and IQ. Subsequent analyses supported the hypothesis that attentional abilities, but not memory, could explain a significant amount of the relationship between NAWM and IQ. The final developmental model predicting academic achievement based on NAWM, attentional abilities, and IQ explained approximately 60% of the variance in reading and spelling and almost 80% of the variance in math.


CONCLUSIONS
The authors demonstrated that the primary consequence of reduced NAWM among pediatric patients treated for brain tumors was decreased attentional abilities, leading to declining IQ and academic achievement.
Department of Diagnostic Imaging, St. Jude Children's Research Hospital, Memphis, Tennessee 38105, USA. gene.reddick@stjude.org
Wilburn E
WE
Reddick
Holly A
HA
White
John O
JO
Glass
Gregory C
GC
Wheeler
Stephen J
SJ
Thompson
Amar
A
Gajjar
Laurie
L
Leigh
Raymond K
RK
Mulhern
D000293:Adolescent; D001921:Brain / Q000473:pathology*; D002528:Cerebellar Neoplasms / Q000150:complications / Q000473:pathology / Q000532:radiotherapy*; D002648:Child; D002675:Child, Preschool; D003072:Cognition Disorders / Q000209:etiology* / Q000473:pathology; D016371:Cranial Irradiation / Q000009:adverse effects*; D005260:Female; D006801:Humans; D007223:Infant; D008279:Magnetic Resonance Imaging; D008297:Male; D008954:Models, Biological; D009483:Neuropsychological Tests; D017741:Survivors