Is cognitive training able to improve brain functioning with age?

摘要

n -back working memory training (RCTs?=?41) showed cognitive training benefits for near transfer to working memory on n -back (g?=?0.62) and other working memory tasks (g?=?0.24) and far transfer to cognitive control (g?=?0.16) and fluid intelligence/visuospatial reasoning (g?=?0.16) 3. On far transfer tasks, benefits were stronger against passive versus active controls, but benefits were not found to be moderated by the number of sessions, hours training, age or verbal versus nonverbal n -back training. Finally, a meta-analysis of RCTs of computerized cognitive training in older adults with MCI or dementia (MCI RCTs?=?17; dementia RCTs?=?12) revealed training-related benefits in MCI but not dementia 2. In MCI, training-related benefits were observed for global cognition (g?=?0.38), verbal learning (g?=?0.39), verbal memory (g?=?0.42), nonverbal learning (g?=?0.50), working memory (g?=?0.74), attention (g?=?0.44) and psychosocial functioning (g?=?0.52) 2. No detectable benefits were found for nonverbal memory, executive function, processing speed, visuospatial skills, language, or daily living, and the observed differences were not found to be moderated by the use of active versus passive controls. General cognitive training benefits were also reported in a meta-analysis of pooled data on healthy older adults and MCI patients, with stronger benefits for working memory training over other training domains and for near over far transfer tasks 5. In dementia, a weaker training-related benefit on overall cognition (g?=?0.26) was observed, but the benefit was not significant (g?=?0.17) after removing two outlier studies 2.fMRI RCTs of cognitive training in older adultsIn fMRI research, two RCTs have examined the effects of working memory training in older adults 6,7. In one RCT in healthy older adults, progressive training to increase visuospatial and verbal working memory span, compared with low-capacity working memory repetitive practice, led to training benefits in working memory capacity over the training sessions and transferred to sustained attention and episodic memory but not to inhibitory control or nonverbal reasoning 6. Although progressive working memory training benefits were not shown to increase working memory capacity on tasks completed in the scanner, progressive working memory training led to decreased activation, under higher working memory demand, in right dorsolateral prefrontal, right superior temporal and bilateral occipital (i.e.,?lingual gyrus) cortices. In the other RCT in healthy older adults, progressive training on an n -back working memory task, compared with passive control, led to training benefits in n -back capacity and transferred to memory updating in an untrained delayed-recognition working memory task 7. Progressive n -back training led to decreased activation, under higher working memory demand, in both the n -back and delayed recognition working memory tasks within left dorsolateral prefrontal cortex and decreased activation was associated with increased working memory capacity gains. Thus, across these two studies, progressive working memory training led to decreased activation in dorsolateral prefrontal cortex under higher working memory demand.In an RCT in healthy older adults, variable-priority divided attention and fixed-priority divided attention training, compared with focused attention training, revealed a divided attention training benefit of reduced divided attention performance costs and a variable-priority divided attention training benefit of reduced performance costs moderated by attention priority 8. Variable-priority training led to increased activation in right dorsolateral prefrontal cortex in dual-task conditions, and reduced post-training dual-task performance cost was associated with greater activation. Focused attention training, in contrast, led to reduced single-task activation bilaterally within dorsolateral prefrontal cortices, with shorter single