Table 1.

Systematic reviews and meta-analyses addressing a healthy older population.

Review	Main Characteristics	Participants	Interventions	Skills Measured	Follow-On	Effect Size
Bhome et al., (2018)	Comm. Context 22 RCTs No patients with MCI or dementia, or significant psychiatric or physical comorbidities	Total N: 1639 TG = 824 CG = 815 MA = no data GEN = no data YE = no data CF = no data	TG = Cognitive training (by applying manual or self-applied strategies) CG = Passive control, waiting list, informational talks or group activities at the community center FORMAT = Group interventions FREQUENCY = Programs from 4 to 16 weeks, especially 8-week programs, with approximately 1.5 h sessions, from 1 to 3 weekly sessions)	General cognitive functioning Subjective psychological well-being	All pre-post 4 follow-ups (between 1 and 6 months).	0.13 General cognitive functioning 0.23 Subjective psychological well-being
Chiu et al., 2017	Comm. Context 31 RCTs Interventions in cognitive training Older adults with normal cognitive functions, with no diagnosis of MCI or dementia	N total = 5499 TG = 3555 and CG = 1944 MA = 72.57 (from 65 to 96) GEN = 67.7% (F); 32.3% (M). YE = 13.5 CF = 26.8	TG = cognitive training (of the 31 RCTs, 14 analyzed general cognitive function, 20 memory, 20 attention, 22 executive function and 6 visuo-spatial capacity) CG = Most were passive control groups, 5 studies with a waiting list and 5 studies with informational talks or some type of education. FORMAT: 13 studies with group interventions and 17 studies with individual interventions FREQUENCY: Session duration approx. 1 h (20 min to 2 h). From 1 to 5 weekly sessions, from 2 to 20 weeks, and from 8 to 60 total sessions according to the study.	General cognitive functioning Memory Attention Executive function Visuo-spatial capacity	All pre-post 10 follow-ups (2, 3, 4, 6 months, 1 or 2 years depending on the study)	0.42 General cognitive functioning 0.35 Memory 0.22 Attention 0.42 Executive function 0.18 Visuo-spatial capacity
Kelly et al., 2014	Comm. Context 31 RCTs > 10 participants per condition Intervention of cognitive training or general mental stimulation Participants: > 60 years without CI	Total N = 4555 TG = 2192 and CG = 2363 MA = 71.8 (from 60 to 99) GEN = no data YE = no data CF = no data	TG = cognitive training and interventions with mental stimulation CG = Passive and active (DVD or educational lectures, training in health promotion, computer games without mental training, or some type of non-structured learning). FORMAT = 7 studies with group interventions and 24 studies with individual interventions FREQUENCY = Session duration approx. 1 h (30 min to 2 h). From 1 to 5 weekly sessions, from 2 to 24 weeks, and from 8 to 75 total sessions according to the study.	General cognitive functioning Memory Executive function	All pre-post 16 follow-ups (2, 3, 4, 6, 8 or 9 months, 1, 2, 3 or 5 years depending on the study).	No data available
Reijnders et al., 2013	Comm. Context and clinical settings 27 RCTs - 21 Healthy older adults - 6 E. with MCI 8 Clinical Studies Participants: healthy older adults or with MCI Any type of cognitive intervention Subjective and/or objective measures of results	N totalhea = 2520 N totalMCI = 410 TGhealthy = 1499 CGhealthy = 1021 TGMCI = 216 CGMCI = 194 MAhealthy = 71.6 (from 60 to 83) MAMCI = 69.4 (from 60 to 78) GEN = no data YE = no data CF = no data	CT = cognitive interventions (memory, executive function, attention, etc.) CG = 10 studies with healthy participants and 2 with MCI had passive control groups (waiting list) and 11 studies with healthy participants and 4 with MCI had active control groups. FORMAT: Healthy: Group interventions in 10 studies, individual interventions in 10 studies and 1 study used both MCI: Group interventions in 4 studies and individual interventions in 2 studies FREQUENCY: Healthy: Session duration approx. 1 h (30 min to 2 h) From 3 to 180 weeks. MCI: Session duration approx. 1 h (30 min to 2 h) From 5 to 20 weeks.	Healthy/MCI 21/6 RCTs: Memory 8/2 RCTs: Executive function 3/0 RCTs: Intelligence (fluid) 2/0 RCTs: Attention 1/3 RCTs: General cognitive functioning 2/1 RCTs: Functional capacity	All studies are pre-post. Healthy: 5 studies included follow-on data from one year later. MCI: 2 studies included follow-on data from 3-4 months later.	No data available

Note. TG = treatment group; CG = control group; MA = mean age; GEN = gender; YE = mean years of education; CF = cognitive function; MCI = mild cognitive impairment.