BOSTON — Working memory training can significantly improve symptoms in adolescents receiving medical treatment for attention-deficit/hyperactivity disorder, Dr. Bradley S. Gibson said in a poster presentation at a meeting of the Society for Research in Child Development.
In the first U.S. investigation of the Cogmed Working Memory Training system—a computer-based training program developed at the Karolinska Institute in Stockholm—Dr. Gibson and his colleagues administered the program to 12 adolescents aged 12–14 years who had been previously diagnosed with ADHD. The investigators observed significant decreases in inattention and significant improvements in both the working memory and other executive functions.
The findings validate those reported in 2005 by Cogmed developer Dr. Torkel Klingberg and colleagues (J. Am. Acad. Child Adolesc. Psychiatry 2005;44:177–86) showing that the intensive training on a battery of verbal and visual-spatial working memory tasks significantly improved symptoms in a sample of Swedish children (aged 7–12 years) diagnosed with ADHD, compared with a placebo group, said Dr. Gibson of the University of Notre Dame (Ind.).
In the current study, the Cogmed program was administered to the students in the computer laboratory of their Midwestern middle school. All of the students received stimulant medication before and during the study. Each student completed 25 1-hour training sessions comprising 11 verbal and visual-spatial working memory exercises over the course of 6 weeks, Dr. Gibson said.
Before and after the intervention, the students were assessed using standardized tests of verbal and spatial working memory and of abstract, nonverbal reasoning. Additionally, parents and teachers completed Vanderbilt ADHD Diagnostic Rating Scale checklists.
“The results indicated significant improvement compared to baseline in all three of the cognitive measures,” Dr. Gibson reported. Additionally, “there were significant decreases in inattentive and hyperactive/impulsive symptoms as rated by parents, and a significant decrease in inattentive symptoms as rated by teachers,” he wrote.
Dr. Gibson pointed to changes in fluid intelligence—the ability to solve problems or adapt to new situations in real time—as a possible mechanism of action. “Working memory improves fluid intelligence, and fluid intelligence appears to reduce ADHD symptoms,” he noted.
In addition to validating the earlier Swedish study, the current findings, while limited by the study’s small size and lack of a placebo control arm, extend the earlier work by “showing that working memory training can enhance some individuals more than others, and more importantly, by showing that individual differences in working memory enhancement are critical for predicting how much the symptoms of ADHD can be improved,” Dr. Gibson wrote.