DTI study: Heavy prenatal alcohol exposure changes white-matter structure in the brain

Prenatal exposure to alcohol changes the white matter of the brain, according to a recent study.

Susanna Fryer and colleagues used a new magnetic resonance imaging (MRI) technology called diffusion tensor imaging (DTI) to look at white-matter structure in 15 children with heavy prenatal alcohol exposure and 12 controls. Nine of the alcohol-exposed children were diagnosed with fetal alcohol syndrome (FAS), while the remainder did not show overt evidence of alcohol-related effects.

“The brains of individuals with fetal alcohol spectrum disorders showed evidence of altered nerve fiber integrity at a microstructural level, even though total brain size was statistically equivalent between alcohol-exposed and comparison participants,” Fryer comments. “Also, within the alcohol-exposed group, we generally found that white-matter microstructure did not differ based on whether youth met criteria for a diagnosis of fetal alcohol syndrome.”

The study authors note that earlier research into the effects of prenatal alcohol exposure on the brain (see related article, Crime Times, 2006, Vol. 12, No. 4, Page 3) detected white-matter abnormalities in the corpus callosum, a bundle of fibers connecting the right and left sides of the brain. The current study extends this finding, revealing additional abnormalities in the frontal and occipital lobes of the brain.

“Among other functions, the frontal lobes are important for planning and regulating behavior at an executive level,” Fryer says. “Individuals with fetal alcohol spectrum disorders may exhibit problems with executive functioning, which can lead to difficulty inhibiting inappropriate or maladaptive responses, impaired attention regulation, and poor judgment and decision-making abilities.” The occipital lobe defects seen in the scans of alcohol-exposed children, she adds, may explain the impaired visual-spatial abilities seen in people with fetal alcohol spectrum disorders.

“Characterization of white matter microstructure in fetal alcohol spectrum disorders,” Susanna L. Fryer, Brian C. Schweinsburg, Olivia A. Bjorkquist, Lawrence R. Frank, Sarah N. Mattson, Andrea D. Spadoni, and Edward P. Riley, Alcoholism: Clinical and Experimental Research, December 22, 2008 (epub prior to print publication). Address: Susanna L. Fryer, 6363 Alvarado Court, Suite 200, San Diego, CA 92120, sfryer@ucsd.edu.

“Prenatal alcohol exposure damages white matter, the brain’s connective network,” news release, San Diego State University and University of California at San Diego, December 19, 2008.