Abnormal cortical thickness alterations in fetal alcohol spectrum disorders and their relationships with facial dysmorphology

Abstract

Accumulating evidence from structural brain imaging studies on individuals with fetal alcohol spectrum disorder (FASD) has supported links between prenatal alcohol exposure and brain morphological deficits. Although global and regional volumetric reductions appear relatively robust, the effects of alcohol exposure on cortical thickness and relationships with facial dysmorphology are not yet known. The structural magnetic resonance imaging data from 69 children and adolescents with FASD and 58 nonexposed controls collected from 3 sites were examined using FreeSurfer to detect cortical thickness changes across the entire brain in FASD and their associations with facial dysmorphology. Controlling for brain size, subjects with FASD showed significantly thicker cortices than controls in several frontal, temporal, and parietal regions. Analyses conducted within site further revealed prominent group differences in left inferior frontal cortex within all 3 sites. In addition, increased inferior frontal thickness was significantly correlated with reduced palpebral fissure length. Consistent with previous reports, findings of this study are supportive of regional increases in cortical thickness serving as a biomarker for disrupted brain development in FASD. Furthermore, the significant associations between thickness and dysmorphic measures suggest that the severity of brain anomalies may be reflected by that of the face.

Figure 1.

Uncorrected P maps representing the significant group difference in cortical thickness for the FASD versus control comparisons across the entire sample of 127 subjects and within LA, SA, and SD site, controlling for age, gender, and total brain volume.

Figure 2.

Illustrations of the significant inferior frontal thickness increases in FASD compared with nonexposed control group both within and across sites. The ROIs were also highlighted as follows: inferior frontal gyrus (IFG; yellow), superior temporal gyrus (STG; pal blue), middle temporal gyrus (MTG; bright pink), and inferior parietal gyrus (IPG; pink).

Figure 3.

Average thickness of the left and right inferior frontal gyrus (IFG), superior temporal gyrus (STG), middle temporal gyrus (MTG), and the inferior parietal gyrus (IPG) of the FASD and control subjects within each site, corrected for age, gender, and total brain volume. The vertical lines represent the standard error bars.

Figure 4.

Relationships between average thickness in left and right inferior frontal gyrus and PFL scores after controlling for age, gender, site, and total brain volume in FASD subjects. The partial correlation coefficient between left and right inferior frontal thickness and PFL partialling out age, gender, site, and total brain volume is −0.36 and −0.18, respectively.