Working memory training in Attention-Deficit/Hyperactivity Disorder: Neural Mechanisms of Change

Institution: University of Toronto

Investigator(s): Rosemary Tannock, Maggie Toplak, Marc Lewis, Umesh Jain

Program: Cogmed RM

Background & Aim: Working memory (WM) is a cognitive function that allows individuals to hold information in mind and manipulate it in the short term. WM is thus crucial for many daily tasks including following directions, reading comprehension, and focusing attention. Individuals with ADHD have poor WM, impacting their ability to pay attention and to learn from experience. WM capacity depends in part on the ability to exclude (inhibit) irrelevant information – which takes up space in WM – and thereby influences what and how much can be held in mind. It is not yet known whether the WM problems in ADHD arise from poor filtering ability and whether WM training will be effective for adults with ADHD. Based on previous WM training research, scientists are also interested in deciphering exactly what neural correlates underlie WM training in ADHD individuals.

In the current project, researchers will study whether young adults with ADHD differ in behavioral and neural indices of WM and associated neural variables compared to their peers without ADHD. The researchers will compare the impact of the standard Cogmed RM protocol (8 WM exercises per day for 25 days) vs. a shorter Cogmed RM protocol (4 WM exercises per day for 25 days) to learn whether filtering efficiency during WM and cognitive control (monitoring and inhibition) share the same neural substrates and whether systematic computerized training of WM produces sustained enhancement of behavior in young adults with ADHD. They will also study whether beneficial effects of 5 weeks of WM training are transferable behaviorally as well as neurally, to cognitive functions other than WM.

Population & Sample Size: N = 150 typical and ADHD adults, ages 18- 25 years

Study 1:
• n = 100 adults with ADHD
• n = 50 adults with no ADHD

Study 2: 80 adults with ADHD from study 1
• n =40 adults in typical adaptive Cogmed training group
• n = 40 adults in brief adaptive Cogmed training group

Design: Randomized, active controlled, test-retest, 2 month follow-up