Attention-Deficit/Hyperactivity Disorder Symptoms as Moderators of the Effects of Cognitive Training on Executive Functioning
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Executive functions (EF) including inhibition and interference control, working memory, and cognitive flexibility or set shifting (Diamond, 2013) have been associated with a range of positive and negative mental health outcomes (Snyder, 2012). Computerized cognitive training (CT) programs focus on improving EFs through systematic and adaptive (i.e., increasingly challenging) tasks targeting multiple EFs. Positive effects of CT have been reported for clinical samples including children, adolescents, and young adults with learning disorders or ADHD (e.g., Klingberg et al., 2005), children and adults with brain injuries (e.g., Barnes et al., 2009; Chen et al., 2015), and adults and older adults with depression and neurodegenerative disorders (e.g., Calkins et al., 2014). CT has also been demonstrated to improve executive functioning in non-clinical samples from children to older adults (e.g., Cortese et al., 2015; Edwards et al., 2013; Murphy et al., 2015). Though many researchers have demonstrated support for near transfer effects (i.e., improvement on untrained tasks that assess the same EF targeted in training of cognitive training, there is limited support for far transfer effects (i.e., improvement on untrained tasks related to a more generalized ability than the trained EF; Rapport, 2013), suggesting that the benefits of CT may not extend to broad indicators of everyday functioning.
The current study examines the effects of CT (specifically Lumosity ) on healthy college students’ executive functioning and ADHD symptoms. Ninety-nine healthy college students were randomly assigned either to complete six weeks of CT (n = 50) or to a comparison condition (n = 49; either no treatment [n = 16] or a six-week coping skills group [n = 33]). Intent-to-treat analyses indicated that students assigned to CT reported near transfer effects in executive functioning on the self-report BRIEF (Behavior Regulation Index measuring inhibition, set-shifting, self-monitoring; Metacognition Index measuring working memory, planning organization; and Global Executive Composite measuring overall EF) and on two conditions of the DKEFS Color-Word Interference test (Color Naming measuring speed of naming colors and Word Reading measuring speed of reading words), but not on the DKEFS Tower Test (a measure of planning). Those in the CT condition completed an average of 25 of the assigned 30 sessions, and within-group analyses indicated that completing more sessions was associated with greater improvement on the Tower Test (r = .33; near transfer) and greater declines in self-reported ADHD symptoms (r = -.27; far transfer). Finally, baseline levels of ADHD moderated effects of CT on one outcome, such that students with initially higher ADHD symptoms demonstrated greater effects of CT on rapid color naming (b = .35; measuring speed of naming colors) compared to students with initially lower baseline levels of ADHD symptoms in the CT group. These results provide limited support for near-transfer of cognitive training to EF skills in healthy college students, and suggest that CT might be particularly helpful for students with subthreshold attention problems.