A preliminary study of the effects of working memory training on brain function

Abstract

Working memory (WM) training improves WM ability in Attention-Deficit/Hyperactivity Disorder (ADHD), but its efficacy for non-cognitive ADHD impairments ADHD has been sharply debated. The purpose of this preliminary study was to characterize WM training-related changes in ADHD brain function and see if they were linked to clinical improvement. We examined 18 adolescents diagnosed with DSM-IV Combined-subtype ADHD before and after 25 sessions of WM training using a frequently employed approach (CogmedTM) using a nonverbal Sternberg WM fMRI task, neuropsychological tests, and participant- and parent-reports of ADHD symptom severity and associated functional impairment. Whole brain SPM8 analyses identified ADHD activation deficits compared to 18 non-ADHD control participants, then tested whether impaired ADHD frontoparietal brain activation would increase following WM training. Post hoc tests examined the relationships between neural changes and neurocognitive or clinical improvements. As predicted, WM training increased WM performance, ADHD clinical functioning, and WM-related ADHD brain activity in several frontal, parietal and temporal lobe regions. Increased left inferior frontal sulcus region activity was seen in all Encoding, Maintenance, and Retrieval Sternberg task phases. ADHD symptom severity improvements were most often positively correlated with activation gains in brain regions known to be engaged for WM-related executive processing; improvement of different symptom types had different neural correlates. The responsiveness of both amodal WM frontoparietal circuits and executive process-specific WM brain regions was altered by WM training. The latter might represent a promising, relatively unexplored treatment target for researchers seeking to optimize clinical response in ongoing ADHD WM training development efforts.

Adaptive working memory training improved brain function in human immunodeficiency virus–seropositive patients

“…In contrast, SN controls showed improved “bottom‐up” networks after adaptive WMT, suggesting that the processing might have become more automated 45. However, the decreased brain activation after adaptive WMT in our participants contrasts with the increased striatal BOLD signals following adaptive WMT in healthy individuals46 and in children with ADHD 47. These discrepant findings might reflect differences in the participant populations and experimental conditions.…”

Executive function in the first three years of life: Precursors, predictors and patterns

“…However, improvements in processing speed have also been linked to cognitive training, at least in older adults (Ball, Edwards & Ross, 2007). To date the main focus of cognitive training in children has been on working memory, rather than processing speed specifically, with targeted training showing working memory improvements in children, including those with ADHD (Holmes et al, 2010;Stevens, Gaynor, Bessette & Pearlson, 2015;Thorell, Lindgvist, Nutley, Bohlin & Klingberg, 2009). There is limited evidence of general transfer effects of training to other EF functions in young children (Egeland, Aarlien & Saunes, 2013;Melby-Lervåg & Hulme, 2013;Wass et al, 2015).…”

Are Measures of Transfer Effects Missing the Target?

“…That is, whether effects seen after training lead to improvements in more broadly defined cognitive functioning and/or in everyday tasks that are highly dependent on WM. While some studies observe transfer effects to for instance inhibition (Klingberg et al 2005;Caeyenberghs et al 2016;Foy & Mann, 2014;Bigorra et al 2015, also Weicker et al 2016 for a meta-analysis), others do not (Stevens et al 2016;Dunning et al 2013;Westerberg et al 2007), and for the field to advance it is important to review the theoretical framework behind such potential transfer and design studies with this framework in mind. Many studies lack a discussion on the expected specificity of the training gains and do not include measures to reflect convergent and discriminant validity (Noack et al 2014).…”

“…While test performance can increase for a number of reasons such as strategy use, motivation, placebo/expectancy effects, regression to the mean to name a few, studies exploring training-related effects in the brain offer convincing support for the malleability of WM. Improvements in WM following training have been shown to be associated with changes in the brain, both with regards to WM-related activity (Olesen et al 2004;Brehmer et al 2011;Stevens et al 2016), changes in the dopaminergic receptor density in cortical and striatal regions (McNab et al 2009;Bäckman et al 2011), and through changes in global integration of the pathways associated with WM (Caeyenberghs et al 2016;Barnes et al 2016). Change in activity has also been observed in the resting brain (Astle et al 2015;Takeuchi et al 2013), effectively demonstrating that the training effect is not (merely) related to differences between individuals or groups in motivation, use of strategy, or even task specific, but demonstrates a change in the underlying function.…”