The effect of exercise intervention on cognitive performance in persons at risk of, or with, dementia: A systematic review and meta-analysis

Background: The aim of this study was to examine the benefits of exercise on the neurocognitive performance of individuals with dementia. Methods: We conducted a systematic search of PubMed, the Cumulative Index to Nursing and Allied Health Literature, and the Cochrane Central Register of Controlled Trials (1966-2014) using the concepts of dementia, cognitive impairment, cognitive function, and exercise. Results: Fourteen randomized controlled trials were included, providing data from 1056 individuals. We found that exercise provided significant improvements in the following assessments: mini mental state examination, mean difference (MD) 1.17 (95% confidence interval [CI] 0.75-1.59, 'P' < 0.00001); Alzheimer's Disease Assessment Scale, MD -1.41 (95% CI -2.48--0.34, 'P' = 0.01); Clinical Dementia Rating scale, MD -0.37 (95% CI -0.57--0.16, 'P' = 0.0004); similarities subscale of Wechsler Adult Intelligence Scale Revised, MD 2.21 (95% CI 0.75-3.67, 'P' = 0.003); arithmetic subscale of Wechsler Adult Intelligence Scale Revised, MD 1.11 (95% CI 0.03-2.20, 'P' = 0.04); Amsterdam Dementia Screening Test 6 picture recognition, MD -2.30 (95% CI -3.59--1.01, 'P' = 0.0005); and clock drawing test, MD 0.75 (95% CI 0.45-1.05, 'P' < 0.00001). Conclusions: Physical activity may improve neurocognitive function in people with cognitive impairments.