Differential effects of cognitive training modules in healthy aging and mild cognitive impairment: A comprehensive meta-analysis of randomized controlled trials

Abstract

This meta-analysis was designed to compare the effectiveness of 2 cognitive training modules, single-component training, which targets 1 specific cognitive ability, versus multicomponent training, which trains multiple cognitive abilities, on both trained abilities (near transfer) and untrained abilities (far transfer) in older adults. The meta-analysis also assessed whether individual differences in mental status interacted with the extent of transfer. Eligible randomized controlled trials (215 training studies) examined the immediate effects of cognitive training in either healthy aging (HA) or mild cognitive impairment (MCI). Results yielded an overall net-gain effect size (g) for the cognitive training of 0.28 (p < .001). These effects were similar across mental status and training modules, and were significant for both near (g = 0.37) and far (g = 0.22) transfer. Although all training modules yielded significant near transfer, only a few yielded significant far transfer. Single-component training of executive functions was most effective on near and far transfer, with processing speed training improving everyday functioning. All modules of multicomponent training (specific and nonspecific) yielded significant near and far transfer, including everyday functioning. Training effects on cognition were moderated by educational attainment and number of cognitive outcomes, but only in HA. These findings suggest that, in older adults, all modules of multicomponent training are more effective in engendering near and far transfer, including everyday functioning, when compared with single-component training modules. (PsycINFO Database Record (c) 2020 APA, all rights reserved).

Figures

Figure 1.

Flowchart summary of literature search. For details of included publication, see Table 1.

Figure 2.

Effects of cognitive training (g) on the seven cognitive constructs in HA and MCI separately. Cognitive training had significant g’s on all cognitive constructs in HA and MCI. Error bars are 95% confidence intervals. K indicates number of studies. Point sizes indicate precision of g, such that larger points have smaller variance and greater precision.

Figure 3.

Transfer effects of single-component cognitive training. Effects from the four different types of single-component cognitive training (targeting either Processing Speed, Reasoning, Executive Functions, or Episodic Memory) on Overall Near and Overall Far transfer are shown. Transfer effects from single-component cognitive training on Overall Near, Overall Far and Everyday Functioning are also depicted. Error bars are 95% confidence intervals. K indicates number of studies. Point sizes indicate precision of g, such that larger points have smaller variance and greater precision.

Figure 4.

Transfer effects of multi-component cognitive training. Effects from the three different types of multi-component cognitive training (Engagement-based, Classroom-based, Laboratory-based) on Overall Near and Overall Far transfer are shown. Transfer effects from multi-component cognitive training on Overall Near, Overall Far and Everyday Functioning are also depicted. Error bars are 95% confidence intervals. K indicates number of studies. Point sizes indicate precision of g, such that larger points have smaller variance and greater precision.

Figure 5.

Funnel plots with all included studies (Top), HA (Bottom Left) and MCI (Bottom Right).

Figure 6.

Scatter plot of g’s as a function of years of formal education for Overall g (Top Center), and separated by Mental Status and Training Modules (Bottom).

Figure 7.

Scatter plot of g’s as a function of the number of cognitive outcomes for Overall g (Top Center), and separated by Mental Status and Training Modules (Bottom).