Improving Executive Functioning in Children with ADHD: Training Multiple Executive Functions within the Context of a Computer Game. A Randomized Double-Blind Placebo Controlled Trial

INTRODUCTION: Executive functions (EFs) training interventions aimed at ADHD-symptom reduction have yielded mixed results. Generally, these interventions focus on training a single cognitive domain (e.g., working memory WM, inhibition, or cognitive-flexibility). However, evidence suggests that most children with ADHD show deficits on multiple EFs, and that these EFs are largely related to different brain regions. Therefore, training multiple EFs might be a potentially more effective strategy to reduce EF-related ADHD symptoms. METHODS: Eighty-nine children with a clinical diagnosis of ADHD (aged 8-12) were randomized to either a full-active-condition where visuospatial WM, inhibition and cognitive-flexibility were trained, a partially-active-condition where inhibition and cognitive-flexibility were trained and the WM-training task was presented in placebo-mode, or to a full placebo-condition. Short-term and long-term (3-months) effects of this gamified, 25-session, home-based computer-training were evaluated on multiple outcome domains. RESULTS: During training compliance was high (only 3% failed to meet compliance criteria). After training, only children in the full-active condition showed improvement on measures of visuospatial short-term-memory (STM) and WM. Inhibitory performance and interference control only improved in the full-active- and the partially-active condition. No Treatment-condition x Time interactions were found for cognitive-flexibility, verbal WM, complex-reasoning, nor for any parent-, teacher-, or child-rated ADHD behaviors, EF-behaviors, motivational behaviors, or general problem behaviors. Nonetheless, almost all measures showed main Time-effects, including the teacher-ratings. CONCLUSIONS: Improvements on inhibition and visuospatial STM and WM were specifically related to the type of treatment received. However, transfer to untrained EFs and behaviors was mostly nonspecific (i.e., only interference control improved exclusively in the two EF training conditions). As such, in this multiple EF-training, mainly nonspecific treatment factors - as opposed to the specific effects of training EFs-seem related to far transfer effects found on EF and behavior. TRIAL REGISTRATION: trialregister.nl NTR2728. Registry name: improving executive functioning in children with ADHD: training executive functions within the context of a computer game; registry number: NTR2728.