Exercising the Brain to Avoid Cognitive Decline

Examining the Evidence

William E Reichman; Alexandra J Fiocco; Nathan S Rose


Aging Health. 2010;6(5):565-584. 

In This Article

Cognitive Training Interventions in Dementia

The results of cognitive interventions in dementia have been mixed. Clare and coworkers conducted a Cochrane Database systematic review on the effectiveness and impact of cognitive rehabilitation and cognitive training focused on improving memory for early-stage AD and vascular dementia.[56] Their review utilized the CDCIG Specialized Register, containing records from MEDLINE, EMBASE, CINAHL, PsycINFO and several other databases. For their analysis, they only included randomized clinical trials comparing cognitive rehabilitation or cognitive training interventions with comparison conditions. Ultimately, six studies met the inclusion criteria. Data from ordinal scales were treated as continuous and a fixed-effects model was applied in calculating WMD and 95% CI. The investigators reported that none of the six studies demonstrated a statistically significant effect of cognitive training interventions in any domain. However, there were indications of some modest effects in various cognitive domains that did not reach statistical significance. The researchers concluded that their findings did not provide strong support for the use of cognitive training interventions for patients with early-stage AD or vascular dementia. However, they tempered their conclusions with the observation that the number of well-controlled studies and numbers of participants was limited at the time of their analysis. In addition, none of the studies they evaluated employed an individualized cognitive training strategy that was specifically geared towards the deficits and needs of each patient.

In a more recent review, Sitzer and coworkers also conducted a meta-analysis.[43] They searched MEDLINE and PsycINFO databases to identify peer-reviewed reports of controlled trials of cognitive training for AD. Based on their inclusion criteria, 17 published articles were analyzed using Cohen's d to establish effect sizes. The authors reported that an overall effect size of 0.47 was observed for all cognitive training strategies across all measured outcomes. Mean effect sizes were higher for restorative (0.54) than for compensatory (0.36) strategies. Cognitive domain-specific effect sizes ranged from 2.16 (verbal and visual learning) to -0.38 (visuospatial functioning). The investigators concluded that cognitive training does demonstrate promise in the treatment of AD. Medium effect sizes were evident for learning, memory, executive functioning, activities of daily living, general cognitive problems, depression and self-rated general functioning. However, they cautioned that most studies report small sample sizes and use of neuropsychological test measures instead of performance-based measures of daily functioning to determine the effectiveness of the training intervention. Finally, a majority of studies employ a combination of treatment strategies that confound the ability to draw conclusions about the effect of any one specific intervention. Therefore, the effectiveness of cognitive training interventions in AD remains equivocal. Clearly more research is needed.