White matter characteristics and cognition in prenatally opiate- and polysubstance-exposed children: A diffusion tensor imaging study

BACKGROUND AND PURPOSE: Prenatal drug exposure may influence the developing brain. Our aim was to study WM characteristics with DTI in children with prenatal opiate and polysubstance exposure and in controls. We assessed whether group differences in FA, DA, and DR could be found and related to cognitive function. MATERIALS AND METHODS: The study was approved by a committee for medical research ethics. Parents signed an informed consent; children gave spoken consent. Our sample included 14 prenatally substance-exposed adopted children (5 girls; age range, 8.6-13.9 years; mean, 11.3 ± 1.7 years) and 14 control children (7 girls; age range, 9.0-10.2 years; mean, 9.8 ± 0.3 years). Tract-based spatial statistics were used to define a common WM skeleton for the sample, and FA was compared between groups throughout the skeleton, controlling for age and sex. Clusters of significant group differences ≥100 voxels (P <. 05) were identified. FA, DA, and DR within clusters were correlated with cognitive function. RESULTS: Ten clusters of FA group differences, mostly in central, posterior, and inferior parts of the brain, were identified (P <. 05), showing lower FA in substance-exposed children. FA and DA correlated positively and DR, negatively with cognitive function across groups. CONCLUSIONS: Prenatally substance-exposed children exhibited lower FA in restricted areas of WM, mostly relatively central, inferior, and posterior, where myelination occurs early in development. Myelin in these areas may be particularly vulnerable to prenatal substance exposure. FA and DR related moderately to cognitive function. Potential confounding factors existed and were considered.