Caudate volume predicts neurocognitive performance in youth with heavy prenatal alcohol exposure

Abstract

Background: Fetal alcohol spectrum disorders result from heavy prenatal alcohol exposure and are characterized, in some cases, by central nervous system anomalies and cognitive impairment. Regional patterns of neuroanatomical abnormalities suggest that alcohol exerts selective damage on the developing fetal brain. This study assessed brain-behavior relationships in a sample of youth with histories of heavy prenatal alcohol exposure. The aim was to characterize how structural brain alterations observed in our previous studies relate to cognitive deficits commonly reported in individuals with histories of heavy prenatal alcohol exposure.

Methods: Twenty-one youth (mean age 13 years) with histories of heavy prenatal alcohol exposure and 7 nonexposed healthy comparison subjects underwent structural magnetic resonance imaging and neurobehavioral testing. Regional brain volumes within the alcohol-exposed group were correlated with neuropsychological measures of cognitive control and verbal learning/recall, as these aspects of cognition have previously been shown to be vulnerable to alcohol teratogenesis.

Results: Between-group effect sizes revealed moderate to large cognitive performance and brain volume decrements in alcohol-exposed subjects, compared with typically developing peers. Within the alcohol-exposed group, volume of the caudate nuclei was the most consistent predictor of neuropsychological performance, after controlling for potentially confounding variables including total brain volume, IQ, and age.

Conclusions: These data are consistent with previous research associating gestational alcohol exposure with structural and functional changes of the caudate nucleus. Our findings extend this previous work by demonstrating that volume reductions of the caudate have behavioral relevance for this population, in relation to cognitive control and verbal learning and recall abilities.

Figure 1

Two representative coronal sections depicting neuroanatomical definitions for the regions of interest examined.

Figure 2

Scatterplots showing relationship between raw caudate volume and neuropsychological test performance, within alcohol-exposed youth (n=19). Neuropsychological test scores were inverted†, if necessary, so that for all neuropsychological variables, higher scores reflect better performance. Open circles depict values of individuals meeting FAS criteria, while closed circles depict values of individuals with histories of prenatal alcohol exposure who did not meet FAS criteria. † The CVLT-C false positives variable was inverted (by multiplying the attained Z-score by -1) so that higher scores indicated better performance. The other variables did not requre inversion, as they were already scaled such that higher scores reflected better performance.