Regular Research Article
The Effect of Exercise Training on Cognitive Function in Older Adults with Mild Cognitive Impairment: A Meta-analysis of Randomized Controlled Trials

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Objectives

Investigations of exercise and cognition have primarily focused on healthy or demented older adults, and results have been equivocal in individuals with mild cognitive impairment (MCI). Our aim was to evaluate efficacy of exercise on cognition in older adults with MCI.

Design

We conducted a meta-analysis of random controlled trials (RCTs) of exercise effects on cognitive outcomes in adults with MCI. Searches were conducted in Medline, EMBASE, CINAHL, PEDro, SPORTSDICUS, PsychInfo, and PubMed.

Participants

Adults aged over 65 years with MCI or Mini-Mental State Exam mean score 24–28 inclusive.

Measurements

Study quality was assessed using the PEDro scale; data on participant and intervention characteristics and outcomes were extracted, followed by meta-analysis.

Results

Fourteen RCTs (1,695 participants; age 65–95 years) met inclusion criteria. Quality was modest and under-powering for small effects prevalent. Overall, 42% of effect sizes (ESs) were potentially clinically relevant (ES >0.20) with only 8% of cognitive outcomes statistically significant. Meta-analysis revealed negligible but significant effects of exercise on verbal fluency (ES: 0.17 [0.04, 0.30]). No significant benefit was found for additional executive measures, memory, or information processing. Overall results were inconsistent with benefits varying across exercise types and cognitive domains.

Conclusions

There is very limited evidence that exercise improves cognitive function in individuals with MCI, although published research is of moderate quality and inconclusive due to low statistical power. Questions remain regarding the magnitude, generalization, persistence, and mechanisms of benefits. Large-scale, high-quality RCTs are required to determine if exercise improves cognition or reduces dementia incidence in those with MCI.

Section snippets

Data Sources and Searches

We performed a systematic review consistent with the preferred reporting items for systematic reviews (PRISMA).18 An electronic database search was originally performed in June 2012 and updated in December 2012 using Medline (1996–first week December 2012), EMBASE (1980–first week December 2012), CINAHL (1980–first week December 2012), PEDro (first week December), SPORTSDICUS (first week December), PsychInfo (1806–first week December 2012), PubMed (first week December 2012). The exercise

Results

Results of the search strategy are presented in Figure 1. The combined search yielded 7,294 potentially eligible papers, was reduced to 102 after reviewing titles and abstracts, which were reviewed in full to determine suitability. Fourteen RCTs met criteria, comprising 1,695 subjects with MCI, with three trials including individuals with documented MCI,24, 27, 28 two with diagnosis of amnestic-MCI,26, 29 and one with memory impairments and memory complaint with MMSE within normal limits.30 The

Conclusions

This systematic review identified 14 RCT trials of exercise in individuals with MCI. The quality of this literature was moderate, and the majority of trials had samples too small for sufficient power to detect small effects. The vast majority of outcomes (92%) were nonsignificant, providing no strong or consistent evidence that exercise of any particular type significantly or robustly improves cognition in individuals at risk of dementia with MCI.

References (40)

  • D. Forbes et al.

    Physical activity programs for persons with dementia

    Cochrane Database Syst Rev

    (2008)
  • M. Angervaren et al.

    Physical activity and enhanced fitness to improve cognitive function in older people without known cognitive impairment

    Cochrane Database Syst Rev

    (2008)
  • J.G.Z. Van Uffelen et al.

    The effects of exercise on cognition in older adults with and without cognitive decline: a systematic review

    Clin J Sport

    (2008)
  • E. Ash et al.

    Is amnestic mild cognitive impairment a useful concept?

    Aging Health

    (2011)
  • F.E. Matthews et al.

    Two-year progression from mild cognitive impairment to dementia: to what extent do different definitions agree?

    J Am Geriatr Soc

    (2008)
  • S. Barber et al.

    Is there a role for physical exercise in preventing decline in people with mild cognitive impairment?

    Age Ageing

    (2012)
  • B. Winblad et al.

    Mild cognitive impairment—beyond controversies, towards a consensus: report of the International Working Group on Mild Cognitive impairment

    J Intern Med

    (2004)
  • D. Moher et al.

    Preferred reporting items for systematic reviews and meta-analyses: the PRISMA statement

    BMJ

    (2009)
  • W. Chodzko-Zajko et al.

    Exercise and physical activity for older adults

    Med Sci Sports Exerc

    (2009)
  • Physiotherapy Evidence Database scale (PEDro), C.f.E.-B. Physiotherapy and M.D.T.G.I.f.G. Health, Editors. Available...
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