Thalamic Nuclear Volumes in Fetal Alcohol Spectrum Disorders: From Adolescence to Middle-Age Twenty Years Later

Background: Midline orofacial and brain structures, including the multinucleated thalamus, may be differentially sensitive to prenatal alcohol exposure and vulnerable to accelerated aging. Methods: Two sets of magnetic resonance imaging (MRI) data separated by 20 years are reported for control individuals, individuals with fetal alcohol syndrome (FAS), and nondysmorphic individuals with heavy fetal alcohol exposure (FAE). MRI1 included 179 participants, with 69 participants reassessed at MRI2. Segmentation produced estimates of bilateral thalamic volume and 10 bilateral nuclei, which were aggregated into anterior, ventral, posterior, and medial volumes. Differences were assessed with and without correction for intracranial volume (ICV). Results: MRI1 revealed stepwise group differences in ICV, total thalamic volume, and anterior and ventral regions uncorrected for ICV, where control > FAE > FAS. Corrected for ICV, the smaller volumes persisted in the anterior and ventral regions, although differences between the FAE and FAS groups were attenuated. Nuclei volumes were selectively smaller in the alcohol-exposed groups than in the control group even after controlling for ICV. Longitudinally, thalamic volumes typically declined over time, maintaining the stepwise effects and with little evidence for accelerated decline in the FAE or FAS groups. Conclusions: These novel data revealed stable deficits in thalamic nuclei of the groups with heavy prenatal alcohol exposure. After 20 years, the deficits persisted but without accelerated age-related decline and following the same aging pattern as control individuals. Despite parallel aging functions in all groups, ICV adjustment yielded volume deficits localized to the anterior and ventral thalamic nuclei, differing from patterns in the remaining thalamic nuclei and cortical brain structures.