Table 2.

Systematic reviews and meta-analyses addressing an older population with mild cognitive impairment (MCI).

Review	Main Charac-Teristics	Participants	Interventions	Skills Measured	Follow-On	Effect Size
Smart et al., 2017	Clinical context 9 RCTs Cognitive interventions participants >60 years old with MCI diagnosis	N total = 676 TG = 378 CG = 298 MA = 70.31 (from 65 to 78) GEN = 72.6% (F); 27.4% (M). YE = no data CF = no data	TG = traditional cognitive training CG = 2 studies with passive control groups (waiting list) and 7 studies with an active control group. FORMAT: All were group interventions except one study with individual training. FREQUENCY: Session duration approx. 1.5 h (45 min to 2.5 h). From 1 to 3 weekly sessions, from 4 to 24 weeks, and from 6 to 72 total sessions according to the study.	General cognitive functioning Functional capacity	All pre-post 7 short-term follow-ups (2 weeks to 3 months)	0.38 General cognitive functioning
Chandler et al., 2016	Clinical context 24 RCTs Cognitive interventions Participants with MCI	T total N = 1100 C total N = 783 TG = 1100 CG = 783 MA = no data GEN = no data YE = no data CF = no data	TG = 24 Cognitive interventions CG = 14 studies with passive control groups (waiting list) and 10 studies used active control groups. FORMAT: 21 group interventions and 3 studies with individual training. FREQUENCY: Session duration approx. 2 h. From 1 to 3 weekly sessions, from 4 to 48 weeks, and from 4 to 78 total sessions according to the study.	General cognitive functioning Functional capacity Frame of mind Quality of life	All pre-post 8 studies with therapist-based interventions (from 1 to 28 months) 5 multimodal studies (from 1 to 18 months)	0.21 General cognitive functioning 0.23 Functional capacity 0.16 Frame of mind 0.10 Quality of life
Simon et al., 2012	Clinical context 14 RCTs 6 studies without a control group, of which 1 is a single case study. Cognitive intervention Participants with MCI	Total N = 3575 TG = 580 CG = 2995 MA = no data GEN = no data YE = 11.86 CF = no data	TG = cognitive training (especially in episodic memory) CG = 6 studies without a control group. 11 studies with passive control groups (4 studies with a waiting list) and 3 studies with active control groups: informational talks or some type of education. FORMAT: 10 studies with group interventions and 10 studies with individual interventions FREQUENCY: Session duration approx. 1.5 h (45 min to 2 h). From 1 to 5 weekly sessions, from 2 to 12 weeks, and from 6 to 30 total sessions according to the study.	Memory Functional capacity Frame of mind	All pre-post 10 follow-ups (2, 3, 6 months, 1 or 2 years depending on the study).	No data available
Gates et al., 2011	Clinical context 5 RCTs, 2 UCTs (uncontrolled population) 3 NRCTs (non-randomized population) Cognitive intervention Participants with MCI	Total N = 305 TG = 169 CG = 136 MA = 74 (from 62 to 91) GEN = 57.84% (F); 42.16% (M). YE = no data CF = 26.3	TG = 6 studies with cognitive training (3 RCTs, 2 UCTs, 1 NRCT) and 4 studies with training in memory strategies (2 RCTs, 2 NRCTs). CG = 2 studies without a control group, 5 studies with passive control groups (2 studies with a waiting list) and 3 studies with active control groups FORMAT: 4 studies with group interventions and 2 studies with individual interventions and 4 studies with no information on format FREQUENCY: 1 h session duration (45 min to 2 h). From 1 to 5 weekly sessions, from 3 to 52 weeks, and from 6 to 100 total sessions according to the study.	General cognitive functioning Memory Attention Executive function Visuo-spatial capacity Functional capacity Frame of mind	All pre-post 4 follow-ups (3, 5 and 6 months depending on the study).	0.30 Memory
Stott and Spector 2011	Comm. Context and clinical settings 3 RCTs, 3 UCTs (uncontrolled population) 2 NRCTs (non-randomized population) Cognitive intervention, cognitive rehabilitation or memory interventions. Participants with MCI	Total N = 280 TG = 172 CG = 108 MA = no data GEN = no data YE = no data CF = no data	TG = 7 studies with cognitive training and 3 studies with cognitive rehabilitation CG = 2 studies without a control group and 8 studies with passive control groups (2 studies with a waiting list) FORMAT: 4 studies with group interventions and 6 studies with individual interventions FREQUENCY: 2 h session duration (45 min to 2 h). From 1 to 5 weekly sessions, from 3 to 12 weeks, and from 3 to 30 total sessions according to the study.	General cognitive functioning Memory Functional capacity Frame of mind	All pre-post No follow-up data	No data available
Li et al., 2011	Clinical context 12 RCTs 8 studies without a control group Stimulation/ Cognitive training or Cognitive Rehabilitation. Participants with MCI	Total N = 690 TG = 444 CG = 246 MA = 73.3 (from 61 to 79) GEN = 54.2% (F); 45.8% (M) YE = 12.9 CF = no data	TG = Cognitive training or Cognitive Rehabilitation. CG = 8 studies without a control group, 7 studies with passive control groups (6 studies with a waiting list) and 5 studies with active control groups FORMAT: 9 studies with group interventions and 11 studies with individual interventions FREQUENCY: Session duration 1.5 h (45 min to 2 h). From 1 to 5 weekly sessions, from 2 to 14 weeks, and from 5 to 103 total sessions according to the study.	General cognitive functioning Memory Executive function Visuo-spatial capacity Frame of mind	All pre-post No follow-up data	0.41 General cognitive functioning 0.45 Memory 0.35 Attention 0.27 Executive function 0.43 Visuo-spatial capacity 0.35 Frame of mind 0.27 Functional capacity 0.32 Quality of life

Note. TG = treatment group; CG = control group; MA = mean age; GEN = gender; YE = mean years of education; CF = cognitive function; RCT = randomized controlled trial; UCT = uncontrolled trial; NRCT = non-randomized controlled trial.