Memory training lifts some ADHD symptoms
VIENNA — A computerized method of systematically training working memory provides a nonpharmacologic means of reducing inattentive symptoms in children who have attention-deficit/hyperactivity disorder, Dr. Torkel Klingberg said at the annual congress of the European College of Neuropsychopharmacology.
In his randomized, double-blind, multicenter, controlled trial, parents of children who received this proprietary method of working memory training rated their children’s ADHD symptoms as improved by 1 full standard deviation more than did parents of children in the control arm.
The improvement was seen largely in inattentive symptoms, where the treatment effect size was greater than typically reported with stimulant medication. Working memory training had far less impact on hyperactivity symptoms, according to Dr. Klingberg, professor of cognitive neuroscience at the Karolinska Institute, Stockholm.
The improvements in both working memory and ADHD symptoms were sustained long term in this study of 53 children aged 7-12 years who were not on stimulant medication. Eighty-five percent of the improvement in visuospatial working memory documented on the span-board task at the conclusion of 5 weeks of training was retained at retesting 5 months later. A 2-week training refresher boosted the improvement back up to 100%.
Forty-two percent of blinded parents indicated in interviews that the reduction in their children’s ADHD symptoms noted at the end of training was maintained over the next 5 months, and an additional 40% noticed further symptomatic improvement during that period. The most likely explanation for this surprising late additional symptomatic improvement is that the gains in working memory enabled children to more effectively tackle homework and other complex tasks, Dr. Klingberg said.
The children also showed significant improvements in laboratory tasks measuring complex reasoning, response inhibition, and verbal working memory. This indicates that the effects of working memory training had spread to nontrained executive function tasks, he said.
Working memory is the ability to retain information during a delay, typically a few seconds, then retrieve it to perform such everyday tasks as solving problems, remembering instructions, reading with comprehension, and controlling attention. Working memory is part of executive function, and working memory deficits are common in ADHD.
Dr. Klingberg is credited as a pioneer in demonstrating that working memory can be improved with training, and that this yields gains in other executive functions and a reduction in ADHD symptoms.
The computer-based working memory training program used in his studies was developed by Cogmed, a Stockholm-based company. Dr. Klingberg is the company’s founder and senior scientific adviser. Participants in his multi-center, double-blind trial trained for 40 minutes per day, 5 days per week, for 5 weeks. The program includes an algorithm for increasing the difficulty of the working memory tasks. Children do the exercises on the Internet, and that enables their activity to be monitored.
The neuroanatomic rationale for working memory training in ADHD comes from a magnetic resonance brain imaging study Dr. Klingberg and his colleagues conducted in healthy young adults. Working memory training resulted in increased brain activity in the dorsolateral prefrontal cortex and the parietal association cortex while subjects performed a working memory task. These areas of the brain have been implicated in ADHD, he noted.
The use of stimulant medication does not interfere with working memory training. In fact, a slightly greater improvement in working memory was documented in 70 ADHD patients on medication than in 66 not on medication in a study now in press, Dr. Klingberg said.
The efficacy of the Cogmed program was recently confirmed in an independent validation study conducted by Bradley S. Gibson, Ph.D., director of the perception and attention laboratory at the University of Notre Dame (Ind.).
In addition, clinical trials are underway evaluating working memory training in patients with stroke or traumatic brain injury.
Dr. Joseph Biederman, session cochair, and professor of psychiatry at Harvard Medical School, Boston, noted that not all children with ADHD have working memory deficits, and he asked what point there was in providing working memory training to those without such deficits.
“To be honest, we don’t know all of the effects here,” Dr. Klingberg replied. “But we know that [methylphenidate] improves cognitive abilities in all subjects, irrespective of whether they have ADHD, perhaps by improving supportive executive functioning.”
BY BRUCE JANCIN
COPYRIGHT 2008 International Medical News Group
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