Training of visuo-spatial working memory improves behavior in kids with ADHD

Research institution: New York University

Research title: A randomized controlled of two forms of computerized working memory training in ADHD

Researchers: Lucas, C., Abikoff, H., Petkova, E., Gan, W., Sved, S., Bruett, L., Eldridge, B.

Training program used in research: Cogmed RM

Presented: Poster presented at the meeting of the American Psychiatric Association, May 2008

Overview: Working memory (WM) is a key cognitive function that allows individuals to hold information in mind for brief periods of time. This ability plays an important role in countless daily tasks including following directions, accurately tracking conversations, reading comprehension, solving complex math problems, and staying focused on a project. Current theories of ADHD that emphasize the critical role of executive functions highlight WM deficits as an important aspect of the disorder. In fact, research has shown that many individuals with ADHD have poor WM compared to same age peers without the disorder (Westerberg et al., 2004).

In 2002, Klingberg et al. reported evidence that WM capacity could be improved with intensive training. In a randomized, controlled trial conducted with 53 children diagnosed with ADHD, WM training was found to yield significant gains in non-trained WM tasks and in a reduction of ADHD symptoms, as reported by parents (see for a review). Further,additional controlled studies using WM training have reported positive results in other groups including younger and older adults without ADHD, typically developing preschoolers, and stroke victims. However until recently, controlled studies documenting positive effects in children with ADHD have not been reported.

At the May 2008 meeting of APA, Dr. Christopher Lucas and his colleagues from NYU Medical School presented new data on the use of WM training in children diagnosed with ADHD. Fourty-six children aged 7 -12 years, who were participating in an intensive summer treatment program for ADHD, were randomly assigned to two WM training groups – auditory or visuo-spatial. The researchers hypothesized that ADHD children who received visuo-spatial training would show greater WM improvements and decreased ADHD symptoms than children who received auditory training. Training took place for 30-35 minutes per day, 4 days per week, over a 6-week period so that a target of 25 training days could be provided. An auditory training exercise might involve presentation of a string of digits in a particular order (ie., “2 4 5 6 8”) and a prompt for the child to recall the digit span via the keyboard either forwards (ie.,“2 4 5 6 8”) or backwards (ie.,“8 6 5 4 2”).A visuo-spatial training task might prompt the child to recall the location of different objects that light up on the computer screen. Examples of computerized working memory training tasks can be found at auditory and visuo-spatial training protocols automatically increased the difficulty level of the working memory tasks depending on how well the child performed, becoming more difficult when the child was successful and easier when the child was struggling. These adjustments were made on nearly a trial by trial basis by increasing or decreasing the number of items to be recalled. As a result, the child was consistently challenged to work at their maximum performance level without the task becoming so difficult that they might become frustrated and give up.

In order to assess whether children who received visuo-spatial training showed greater gains in WM performance than children who received the auditory training, the researchers administered a comprehensive WM assessment before and after training. This assessment included non-trained WM tasks that measured the same underlying WM ability but that differed in presentation and mode of response than WM tasks trained with during the program. Testing with non-trained WM tasks ensured that improvement on the tasks from pre- to post-testing was not the result of practice or improved strategy use but instead, the result of increased underlying WM capacity.

To find whether visuo-spatial working memory training was associated with behavioral improvements, researchers examined the number of positive behavior points (i.e., points awarded for behaving appropriately and following camp rules) that children in both groups received from camp counselors between weeks 4 and 6 of WM training. The counselors who provided behavioral ratings (ie., awarded points) were blinded to the training condition of the children. Because some of the participants in this study were being treated with medication and all were involved in an intensive behavioral therapy program, it is likely that the children had already evidenced noticeable behavior modification. It is thus important to note that any additional behavioral change observed by the blinded raters after WM training would have had to have been significant in light of impacts of the other treatments at play.

Before and after the training, children were tested on several non-trained measures of WM. Consistent with the researchers’ prediction, children who received visuo-spatial WM training performed significantly better on WM tasks than children who received auditory WM training. Further, children who received visuo-spatial WM training earned significantly more positive behavior points from the camp counselors. Thus, these children were rated as doing a better job of consistently following camp rules and behaving appropriately.

Summary and Implications
Results from this randomized, controlled study support the benefits of WM training for children with ADHD and indicate that training of visuo-spatial working memory is especially important for this population. Not only was this training study associated with an increase in positive behavioral outcomes above and beyond the medication and behavior treatments already in place but also, it employed blinded raters to assess children’s behavior. It is important to note however that teacher and parent behavioral ratings were not collected and that no long term follow up was conducted to gauge sustained improvements over time.