But to the study at hand, it seems that, even if you take into account their general cognitive deficits, kids with FASD have math-specific deficits. This article looks into why that is the case, and they find it in abnormalities in the white matter of several parts of the brain, which they discovered through diffusion tensor imaging of 12 kids.
"We found that four different brain areas show correlations between structure and mathematical ability in children with FASD," said Lebel. "Two of these regions in the left parietal area are very similar to previous findings in healthy children and in a rare genetic disorder, suggesting that these regions are key areas for math across diverse populations. The two other regions -- the cerebellum and the brainstem -- might be unique to children with FASD in terms of math-structure relationships.