Deficits in children with ADHD, early alcohol exposure similar but with different causes

Children with fetal alcohol exposure and children with attention-deficit/hyperactivity disorder have similar learning deficits, but treatments for one may not be effective for the other, according to a study to be published in the March issue of Alcoholism: Clinical & Experimental Research.

Fetal alcohol exposure and ADHD are linked to poor academic performance in cognition and attention, so researchers from Wayne State University School of Medicine tried to pinpoint the exact brain areas affected by each disorder with the aim that this research could lead to the creation and development of new and improved treatments.

Joseph L. Jacobson, PhD, and colleagues assessed 262 black 14-year-olds, whose mothers were recruited during pregnancy and interviewed extensively regarding their alcohol use to determine the amount of alcohol the child was exposed to before birth. The children were evaluated for ADHD symptoms at ages 7.5 and 14 years by parent/guardian and teacher reports, and their number processing abilities were assessed at 14 years.

Children with fetal alcohol exposure demonstrated strong deficits in number comparison, whereas children with ADHD demonstrated deficits in attention and memory. Thus, although number processing is affected in ADHD and fetal alcohol exposure, the exact cause of the difficulties appears to be different.

In a related study using functional magnetic resonance imaging conducted in Cape Town, South Africa, the researchers found that, when given simple number processing problems, alcohol-exposed children appear to be able to recruit different brain regions to compensate for the damage done to the areas of the brain. However, the recovery is never complete and is variable at best, depending on the child.

“The extent of the brain damage experienced by the individuals is an important predictor of recovery of function and is influenced by the quantity and duration of alcohol consumed while in utero and various genetic and metabolic characteristics of the mother and fetus,” Julie A. Kable, PhD, an assistant professor in the department of pediatrics at the Emory University School of Medicine, said in a press release. “More extensive damage leads to less available resources to compensate.”

However, Jacobson does not consider the performance of the children in this study to constitute recovery. He said the alcohol-exposed children in the functional MRI study performed as well as the control group on the arithmetic tasks only because of the relatively easy nature of the problems selected for that study.

Disclosure: Drs. Jacobson and Kable did not respond to requests for financial disclosures.

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