Researcher Susanna L. Fryer and her team at San Diego State University's Center for Behavioral Teratology used a form of MRI imaging called Diffusion Tensor Imaging to analyze the white matter in the brains of 27 participants, aged eight to 18. Fifteen of the individuals had had heavy prenatal alcohol exposure and 12 had not. In the alcohol exposure group, some of the participants met the criteria for FAS and some did not....[W]hite matter in the brains of the alcohol-exposed group showed structural differences from that of the normal group.
The team found that the white matter in the brains of the alcohol-exposed group showed structural differences from that of the normal group. What's more, the changes in the white matter were most pronounced in two areas that previous studies had not shown before: the frontal and occipital lobes.
The frontal lobes are important in "executive" planning and decision-making. Fryer explains that those affected with FAS "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 lobes of the brain house the vision centers that are critical for processing visual information at the highest level. Abnormal white matter found in these regions is likely responsible for the impaired visual-spatial abilities in people affected with FAS.
Coauthor Jeffrey R. Wozniak points out that as technology improves, it will be possible to attribute "increasingly subtle forms of brain damage and cognitive deficits" to FAS, in individuals who had even low levels of alcohol exposure prenatally. To the question, "how much alcohol is safe during pregnancy?" the researchers caution that it is unclear whether there exists a safe amount at all. Wozniak ends by saying that it is regrettable "that the public and some physicians conclude without scientific evidence that alcohol consumption during pregnancy is safe as long as it is not 'too much.'"
