Prenatal alcohol exposure is the largest single known cause of mental retardation and developmental disabilities in children. Neuroimaging and neuropsychological studies have yielded insights into the underlying effects of alcohol, as well as the resulting cognitive deficits and behavioral symptoms. However, much of the research has focused on children meeting full diagnostic criteria for Fetal Alcohol Syndrome (FAS), who represent 10% or fewer of those affected by prenatal alcohol exposure.
Children with "partial FAS" (pFAS) represent a dramatically understudied group. We will use advanced Magnetic Resonance (MR) imaging methods, including Diffusion Tensor Imaging (DTI), to demonstrate that children with pFAS have abnormalities in brain white matter. We expect to find that these brain abnormalities are correlated with clinical neuropsychological measures, including behavioral inhibition. Because hyperactivity and impulsivity are very common symptoms of fetal alcohol exposure, understanding the brain correlates of these behaviors will be of significant scientific and clinical value.
Unlike conventional MR data, which provides a measure of tissue volume, DTI allows for characterization of tissue integrity at the microstructural level. DTI is particularly well suited to the study of neurodevelopmental disorders such as fetal alcohol exposure because it is sensitive both to normal developmental changes (such as myelination) and also to insults that occur against that background of normal developmental change in the brain. Because our preliminary data show significant group differences and correlations with behavioral measures, we believe that the proposed imaging methodology is uniquely sensitive to the underlying brain pathology in milder cases of fetal alcohol exposure.
The next steps in this work are to incorporate a wider age range of children (10 to 17 years of age), increase the sample sizes, and add a third group of children with full-criteria Fetal Alcohol Syndrome. We will study 20 patients with pFAS, 20 control subjects, and 10 subjects with full-criteria FAS. All subjects will undergo MRI scans and receive neuropsychological evaluations. We will compare the groups on volumetric measures and on pre-selected regional measures of fractional anisotropy (FA) and mean diffusivity (MD)—both DTI-derived measures of tissue integrity. We will also correlate findings from these DTI measures with neuropsychological and behavioral measures.
This project will contribute significantly to the field because the proposed methodology is state of the art and will yield unique insights into the full range of effects of alcohol on the developing brain.