title: Computerized cognitive training in cognitively healthy older adults: a systematic review and meta-analysis of effect modifiers.
abstract: BACKGROUND
  New effective interventions to attenuate age-related cognitive decline are a global priority. Computerized cognitive training (CCT) is believed to be safe and can be inexpensive, but neither its efficacy in enhancing cognitive performance in healthy older adults nor the impact of design factors on such efficacy has been systematically analyzed. Our aim therefore was to quantitatively assess whether CCT programs can enhance cognition in healthy older adults, discriminate responsive from nonresponsive cognitive domains, and identify the most salient design factors.
  
  
  RESULTS
  We systematically searched Medline, Embase, and PsycINFO for relevant studies from the databases' inception to 9 July 2014. Eligible studies were randomized controlled trials investigating the effects of ≥ 4 h of CCT on performance in neuropsychological tests in older adults without dementia or other cognitive impairment. Fifty-two studies encompassing 4,885 participants were eligible. Intervention designs varied considerably, but after removal of one outlier, heterogeneity across studies was small (I(2) = 29.92%). There was no systematic evidence of publication bias. The overall effect size (Hedges' g, random effects model) for CCT versus control was small and statistically significant, g = 0.22 (95% CI 0.15 to 0.29). Small to moderate effect sizes were found for nonverbal memory, g = 0.24 (95% CI 0.09 to 0.38); verbal memory, g = 0.08 (95% CI 0.01 to 0.15); working memory (WM), g = 0.22 (95% CI 0.09 to 0.35); processing speed, g = 0.31 (95% CI 0.11 to 0.50); and visuospatial skills, g = 0.30 (95% CI 0.07 to 0.54). No significant effects were found for executive functions and attention. Moderator analyses revealed that home-based administration was ineffective compared to group-based training, and that more than three training sessions per week was ineffective versus three or fewer. There was no evidence for the effectiveness of WM training, and only weak evidence for sessions less than 30 min. These results are limited to healthy older adults, and do not address the durability of training effects.
  
  
  CONCLUSIONS
  CCT is modestly effective at improving cognitive performance in healthy older adults, but efficacy varies across cognitive domains and is largely determined by design choices. Unsupervised at-home training and training more than three times per week are specifically ineffective. Further research is required to enhance efficacy of the intervention. Please see later in the article for the Editors' Summary.
authors.affiliation: Regenerative Neuroscience Group, Brain and Mind Research Institute, University of Sydney, Sydney, New South Wales, Australia.
authors.forename: Amit
authors.initials: A
authors.lastname: Lampit
authors.affiliation: Regenerative Neuroscience Group, Brain and Mind Research Institute, University of Sydney, Sydney, New South Wales, Australia.
authors.forename: Harry
authors.initials: H
authors.lastname: Hallock
authors.affiliation: Regenerative Neuroscience Group, Brain and Mind Research Institute, University of Sydney, Sydney, New South Wales, Australia.
authors.forename: Michael
authors.initials: M
authors.lastname: Valenzuela
mesh_terms: D000368:Aged; D003071:Cognition; D003072:Cognition Disorders / Q000517:prevention & control*; D003201:Computers; D003704:Dementia / Q000517:prevention & control*; D006801:Humans; D007858:Learning; D008568:Memory; D008875:Middle Aged