Computerized Cognitive Training in Cognitively Healthy Older Adults: A Systematic Review and Meta-Analysis of Effect Modifiers

<div><p>Background</p><p>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.</p><p>Methods and Findings</p><p>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>I</i>² = 29.92%). There was no systematic evidence of publication bias. The overall effect size (Hedges' <i>g</i>, random effects model) for CCT versus control was small and statistically significant, <i>g</i> = 0.22 (95% CI 0.15 to 0.29). Small to moderate effect sizes were found for nonverbal memory, <i>g</i> = 0.24 (95% CI 0.09 to 0.38); verbal memory, <i>g</i> = 0.08 (95% CI 0.01 to 0.15); working memory (WM), <i>g</i> = 0.22 (95% CI 0.09 to 0.35); processing speed, <i>g</i> = 0.31 (95% CI 0.11 to 0.50); and visuospatial skills, <i>g</i> = 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.</p><p>Conclusions</p><p>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.</p><p><i>Please see later in the article for the Editors' Summary</i></p></div

Pearson Correlation Data for Skull Shape, Body Size, Body Weight, Angle of the Longitudinal Axis and Deflection of the Olfactory Lobe for N = 13 Dogs.

<p>**: Correlation is significant at the 0.01 level (2-tailed).</p><p>*: Correlation is significant at the 0.05 level (2-tailed).</p

Deviation of the Olfactory Lobe.

<p>a) Cephalic index and deviation of the olfactory lobe using two different methods after normalization of cerebral axis to horizontal. Two exemplar dogs highlighted in boxes are illustrated in parts b) and c) below. b) Angle of deflection method: angle in degrees between centre of mass of brain (CoM_brain) and centre of mass of olfactory lobe (CoM_OL). c) Displacement method: Ratio of the ventral-dorsal distance from centre of mass of brain and centre of mass of olfactory lobe (a′) to overall brain height (b′).</p

Efficacy of CCT on measures of visuospatial skills.

<p>Effect estimates are based on a random-effects model, and studies are rank-ordered by year of publication.</p

Efficacy of CCT on measures of processing speed.

<p>Effect estimates are based on fixed-effects (top) and random-effects (bottom) models, and studies are rank-ordered by year of publication.</p

Efficacy of CCT on measures of nonverbal memory.

<p>Effect estimates are based on a random-effects model, and studies are rank-ordered by year of publication.</p

Characteristics of dogs in this study by cephalic index group (N = 13).

<p>CI: cephalic index. Mean values ± SD.</p

Subgroup analyses of moderators of overall efficacy of CCT in older adults.

<p>^a<i>Q-</i>test for between-group heterogeneity, mixed-effects model. ^bOne study that combined data from both home- and group-based training <a href="http://www.plosmedicine.org/article/info:doi/10.1371/journal.pmed.1001756#pmed.1001756-Berry1" target="_blank">[55]</a> was excluded from this analysis. ^cTotal number of training hours. ^dSession length could not be determined for one study.</p

Cephalic Index Measurement.

<p>For measurement of the cephalic index, skull width was measured from one zygomatic arch to the other and skull length was measured from the nose to the occipital protuberance. Cephalic index (CI) was calculated as (skull width/skull length) ×100.</p

Study characteristics.

a<p>Total number of training hours.</p>b<p>Total number of CCT sessions.</p>c<p>Session length (minutes).</p>d<p>Number of sessions per week.</p>e<p>Defined has having high or unclear risk of bias for blinding of assessors and/or incomplete outcome data.</p>f<p>Measured with the Montreal Cognitive Assessment (MOCA, 1–30 scale).</p>g<p>Means for the whole study (i.e., including groups that were not included in the analysis).</p>h<p>Converted from the Modified Mental State Exam (3MSE, 1–100 scale) to Mini-Mental State Examination (1–30 scale).</p>i<p>Measured with the St. Louis University Mental Status exam (SLUMS, 1–30 scale).</p><p>CNT, Colorado Neuropsychology Tests; MMSE, Mini-Mental State Examination; PS, Posit Science.</p><p>Study characteristics.</p