Training of Working Memory in Children With ADHD

Abstract

Working memory (WM) capacity is the ability to retain and manipulate information during a short period of time. This ability underlies complex reasoning and has generally been regarded as a ®xed trait of the individual. Children with attention de®cit hyperactivity disorder (ADHD) represent one group of subjects with a WM de®cit, attributed to an impairment of the frontal lobe. In the present study, we used a new training paradigm with intensive and adaptive training of WM tasks and evaluated the effect of training with a double blind, placebo controlled design. Training signi®cantly enhanced performance on the trained WM tasks. More importantly, the training signi®cantly improved performance on a nontrained visuo-spatial WM task and on Raven's Progressive Matrices, which is a nonverbal complex reasoning task. In addition, motor activity ± as measured by the number of head movements during a computerized test ± was signi®cantly reduced in the treatment group. A second experiment showed that similar training-induced improvements on cognitive tasks are also possible in young adults without ADHD. These results demonstrate that performance on WM tasks can be signi®cantly improved by training, and that the training effect also generalizes to nontrained tasks requiring WM. Training improved performance on tasks related to prefrontal functioning and had also a signi®cant effect on motor activity in children with ADHD. The results thus suggest that WM training potentially could be of clinical use for ameliorating the symptoms in ADHD.

Will Working Memory Training Generalize to Improve Off-Task Behavior in Children with Attention-Deficit/Hyperactivity Disorder?

“…However, there were no significant changes in teacher ratings in this study, nor were there any changes in a previous study that included teacher ratings [33]. These studies demonstrated partial evidence for the generalization of the training on more global functioning on parent (but not teacher) ADHD ratings scales, improved response inhibition functioning, and complex reasoning, as measured by the Raven's Progressive Matrices [32,33]. Thus, there is some evidence that computerized cognitive WM training may affect broader executive functioning.…”

“…Doubleblind, placebo-controlled studies suggest that participation in 25 sessions of intensive computerized training significantly improves WM performance in children with ADHD [31][32][33]. Enhanced performance on nontrained WM tasks was seen in both visuospatial and verbal WM, and persisted at 3 months and at 6 months after the end of the training period, suggesting that improvements after treatment are durable after an extent of time [31,33].…”

“…WM was traditionally believed to be a fixed genetic trait, the capacity of which could not improve through practice [30]; however, recent studies show that WM can be improved through intensive training [31][32][33][34][35][36]. Doubleblind, placebo-controlled studies suggest that participation in 25 sessions of intensive computerized training significantly improves WM performance in children with ADHD [31][32][33].…”

Is working memory training effective? A meta-analytic review.

“…This variation in the conclusions drawn from current narrative reviews probably reflects the fact that there are very large variations in results across studies in this field. Some studies show very large effects on far-transfer measures (e.g., Klingberg, Forssberg, & Westerberg, 2002), while others show no far-transfer effects at all (e.g., Holmes, Gathercole, & Dunning, 2009). There is also considerable variability in how the studies included in the narrative reviews are selected (e.g., in some cases studies without a control group are included), and this may also help to explain why the reviews reach such disparate conclusions.…”

“…1 Schmiedek, et al 2010, comp 1 Thorell, et al, 2008, comp. 2 Jaeggi, et al 2008Jaeggi, et al 2010Jaeggi, et al 2010Schmiedek, et al 2010, comp 2 Borella, et al, 2011Klingberg, et al 2002 Effect sizes control groups on word decoding (word and nonword reading; N training groups ϭ 197, mean sample size ϭ 28.14; N controls ϭ 156, mean sample size ϭ 22.28). The mean effect size was small and nonsignificant (d ϭ 0.13), 95% CI [Ϫ0.07, 0.35].…”