By Anthony J. Brown, MD
Children exposed to alcohol in the womb have impaired eye blinks compared with their unexposed peers, researchers found in a study they conducted.
Children exposed to alcohol before birth may develop foetal alcohol syndrome - a collection of birth defects and developmental problems that can include delayed growth, significant learning disabilities and abnormal facial features. However, not all children with foetal alcohol syndrome are born with the distinctive facial anomalies of the condition.
Writing in the journal Alcoholism: Clinical and Experimental Research, researchers say their findings indicate that deficits in so-called eye blink conditioning, or EBC, can identify children with probable foetal alcohol syndrome.
"Animal studies have shown that binge consumption of alcohol during pregnancy impairs EBC," study investigator Dr. Sandra W. Jacobson, of Wayne State University School of Medicine, Detroit, explained in a written statement. "We wanted to see if we could use the EBC paradigm to identify underlying or subcortical (brain) deficits that are specifically affected by prenatal alcohol exposure in children," she said.
The study involved 98 five-year-old children in Cape Town, South Africa who had eye blink testing. This area was selected because of its known high incidence of foetal alcohol syndrome.
Overall, 64 of the children were born to heavy drinking mothers, including 12 who met criteria for foetal alcohol syndrome and 18 who met criteria for partial foetal alcohol syndrome.
None of the children with foetal alcohol syndrome achieved normal EBC compared with 75 percent of control children, the team found. Moreover, among children with less severe alcohol-related exposures, it usually took more test sessions to achieve normal EBC than it did for controls.
In addition, the deficits in EBC were not related to IQ or found in nonexposed children with microcephaly (small head size), which are often confounding factors.
"This study clearly links one brain area to the learning deficits experienced by foetal alcohol syndrome children, whether or not they have physical manifestations of the condition, and thus can provide a basis for the development of remediation programs," Lynn T. Singer, Deputy Provost and vice president for academic programmes at Case Western Reserve University, said in a statement.
"Second, since normal human infants reach functional capacity on the EBC response by five months of age, and since the EBC deficit appears to be so sensitive, infants at risk can be identified early in life, and intervention programs can begin when the plasticity of the brain is greatest and have the strongest effect," she added.