Regional cerebellum volume anomalies and associated cognitive function in children with fetal alcohol spectrum disorders

Background: Prenatal alcohol exposure (PAE) significantly impacts cerebellar development, which may affect cognitive function in fetal alcohol spectrum disorders (FASD). We evaluated cerebellar anomalies in children with FASD and an unexposed comparison group using an advanced MRI volumetric method that characterizes cerebellar structure at the level of individual lobules. We also explored associations between the cerebellum and cognitive performance. Methods: Forty-seven children with FASD and 46 typically developing comparisons (ages 8–17 years). Participants completed a 3T MRI scan and cognitive testing including IQ, executive function, visual memory, and visual-motor processing speed. T1-weighted anatomical data were processed with the CerebNet pipeline, which segments the cerebellum into lobules. Univariate and multivariate linear models (with intracranial volume [ICV] as a covariate) examined group volume differences for total cerebellar volumes and individual cerebellar lobules. Exploratory analyses examined associations between cognitive functioning and cerebellum volumes. Results: Participants with FASD demonstrated lower volumes than comparison participants in total bilateral cerebellar white and cortical gray matter, and a smaller total vermis. Participants with FASD had lower regional volumes than comparisons within the bilateral lobules I–IV and V (anterior lobe) and vermis X lobule (flocculonodular lobe). Within the FASD group, a larger volume in the total cerebellar white matter was a significant predictor of better performance on measures of verbal working memory and processing speed. Within the comparison group, a larger volume of lobule V was a significant predictor of better verbal working memory, while a larger volume of lobule I–IV was a significant negative predictor of better verbal working memory. Conclusions: A novel MRI method to evaluate cerebellum morphology in children with FASD suggests that PAE is associated with cerebellum anomalies in a regionally specific manner. The data also suggest that structural anomalies of the cerebellum may have functional consequences for important cognitive skills in children with FASD.