Eye Blink Test Effective for Fetal Alcohol Exposure

A new eye blink test may help identify children exposed to alcohol prenatally and therefore allow them to be treated earlier. Children who have full-blown fetal alcohol syndrome can usually be identified by visible abnormalities of their head and face, but children affected by prenatal alcohol exposure to a lesser degree are not as easily identified.

Scientists have developed an eyeblink conditioning test that can identify alcohol-exposed children who do not have distinctive fetal alcohol syndrome features.

"Eyeblink conditioning (EBC) is a Pavlovian paradigm that involves temporal pairing of a conditioned stimulus, such as a tone, with an unconditioned stimulus, such as an air puff," explained Sandra W. Jacobson, of Wayne State University School of Medicine, and first author of the study in a news release. "Animal studies have shown that binge consumption of alcohol during pregnancy impairs EBC. We wanted to see if we could use the EBC paradigm to identify underlying or subcortical deficits that are specifically affected by prenatal alcohol exposure in children."

"The present study provides the first documentation that clearly points to an fetal alcohol syndrome relationship because of the large sample size, the prospective follow-up of children from birth, and the careful measurement of prenatal exposure to alcohol and other drugs," said Lynn T. Singer, Deputy Provost and vice president for academic programs at Case Western Reserve University. "Moreover, the deficits in EBC were not related to IQ or [found in nonexposed children with] microcephaly, which are often confounding factors."

High Incidence of Fetal Alcohol Syndrome

The researchers examined 98 five-year-olds born to mixed-ancestry women in Cape Town, South Africa, a region known for an extremely high incidence of fetal alcohol syndrome.

"Even knowing the high incidence of FAS that has been documented in rural areas of the Western Cape province, we were surprised to see the very high incidence of children born with FAS and partial FAS (PFAS) in this urban mixed-ancestry cohort," said Jacobson. "Twelve (18.8%) children born to the 64 heavy drinking mothers met criterion for FAS, and an additional 18 (28.1%) for PFAS.

"Not a single child with FAS at this age met criterion for short-delay conditioning as contrasted with 75 percent of the controls. In addition, about two-thirds of the children with PFAS and two-thirds of the heavily exposed nonsyndromal children also did not meet criteria for conditioning.

"Given that we controlled for IQ and that EBC was not impaired in non-alcohol-exposed children with microcephaly, these findings suggest that the EBC deficit does not reflect impaired intellectual ability but rather is a direct effect of the fetal alcohol exposure," Jacobson said.

The study, "Impaired Eyeblink Conditioning in Children with Fetal Alcohol Syndrome," was published in the February 2008 issue of Alcoholism: Clinical & Experimental Research.

Related Information:

• Alcohol and Pregnancy
  
• Pregnant Women Not Getting the Message
  
• Fetal Alcohol Syndrome
  About Pregnancy
  

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