Children exposed to alcohol in the womb have an impaired ability to blink their eyes compared with their unexposed peers, researchers found in a study they conducted.
Children exposed to alcohol before birth may develop fetal 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 fetal 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 fetal 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, said in a statement.
The study involved 98 5-year-olds in Cape Town, South Africa, who had eye blink testing. This area was selected because of its known high incidence of fetal alcohol syndrome.
Overall, 64 of the children were born to heavy drinking mothers. A dozen of the children met criteria for fetal alcohol syndrome; another 18 met criteria for partial fetal alcohol syndrome.
Researchers tested the children by sounding a tone and then following it with a puff of air. The children had 350 milliseconds to blink to avoid the puff, Jacobson said. None of the children with fetal alcohol syndrome learned to blink in time after repeated trials. Only about a third of children exposed to heavy alcohol use learned to blink to block the air.
In contrast, 75 percent of children in a control group learned to respond in time. 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 fetal 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 programs 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.