Table 1.
Characteristics and results of reviewed studies
| Publication | Design | N (% male) | Population | Mean age (SD) | Interventions/ meditation type |
Main cognitive findings + relevant other findings |
|---|---|---|---|---|---|---|
| Alexander et al.40 | RCT Four arms, two time points: pre- and postintervention |
73 (18) TM: 20 MFL: 21 MR: 21 NT: 11 |
Normal to poor cognitive functioning | 80.7 (n.r.) | TM MFL MR All 12 weeks of 40-min daily home practice, 30 min/week instruction NT |
The postintervention contrast 3TM+1MFL-2MR-2NT was sig. for DST ALS, DST WFS, OVT, but not for DST total and Stroop TM scored sig. better on OVT than MFL, MR, or NT postintervention |
| Lavretsky et al.47 | RCT Four arms, two time points: pre- and postintervention |
39 (5) EXP: 23 CTL: 16 |
Family dementia caregivers Mild to moderate depression Normal cognitive functioning |
60.3 (10.2) | EXP: KKYM CTL: Relaxation (listening to instrumental music) Both cond.: 8 weeks, 12-min daily home practice with audio recordings |
Improved overall (MANCOVA) cognitive functioning in EXP relative to CTL. Individually, improvements on Trails B, and MMSE, but not on Trails A and CVLT in EXP relative to CTL Improved mental health (SF-36, Ham-D24) in EXP relative to CTL |
| McHugh et al.52 | RCT Two arms, one time point |
24 (50) EXP: 12 CTL: 12 |
Normal cognitive functioning | 78.58 (n.r.) | EXP: MF instruction CTL: mind wandering instruction Both conditions: one time 15 min |
Sig. lower stimulus overselectivity in EXP than in CTL |
| Moynihan et al.54 | RCT Two arms, four time points: pre-, post-, at 3 and 24 weeks after the intervention |
201 (38) EXP: 101 (38) CTL: 100 (38) |
Elderly without cognitive impairment, uncorrected sensory impairments, psychosis, and stable if on medication | EXP: 73.3 (6.7) CTL: 73.6 (6.7) |
EXP: MBSR: 8 weeks, weekly 120-min sessions, retreat day, 40-min daily home practice CTL: wait list |
Sig. better executive function (Trails B/A) in EXP versus CTL at post but not FU1 and FU2. No sig. differences in Trails A or B at any time Sig. greater leftward frontal alpha asymmetry in EXP versus CTL No sig. difference between groups in depression (CES-D) and perceived stress (PSS) at any time point |
| Oken et al.58 | RCT Three arms, two time points: pre- and postintervention |
31 (20) EXP: 10 Act. CTL: 11 Pass. CTL: 10 |
Family dementia caregivers Normal cognitive functioning Stressed |
64.55 (9.41) | EXP: MF based on MBCT Act. CTL: powerful tools for caregivers education program Both interventions: 7 weeks, weekly 90-min sessions Pass. CTL: no intervention but same amount of respite care as in interventions |
Sig. group differences in postintervention Stroop and ANT alerting, driven by higher ANT scores in EXP and act. CTL than in pass. CTL. No sig. group differences in word learning or ANT executive functioning or when correcting for multiple comparisons Sig. lower perceived stress in EXP and act. CTL than in pass. CTL, no difference between EXP and act. CTL |
| Sun et al.66 | RCT Two arms, four time points: pre-, at 3, 6, 12 months of training |
80 (25) EXP: 40 CTL: 40 |
Chinese Reduced sleep quality |
69.69 (7.89) | EXP: Self-relaxation: PMR + MED (guided visual imagery), 12 months; four initial group sessions and daily home practice with audiotapes CTL: sleep hygiene education brochure |
Improved cognitive functioning (MMSE, WMS) in EXP, worsening in CTL Increased sleep quality in EXP, worsening in CTL |
| Ernst et al.70 | LGT NR Two groups, two time points: pre- and postintervention |
22 (27) EXP: 15 (20) CTL: 7 (43) |
German nursing home residents | Median age 83.5 EXP: 80 CLT: 89 |
EXP: modified MBSR: 8 weeks, weekly 90-min sessions, no retreat day, reduced home practice CTL: no intervention |
No sig. difference in MMSE change between groups Sig. greater improvement in physical health (SF-12), depression (GDS-12R), and severity of major complaints |
| Newberg et al.75 | LGT NR Two groups, two time points: pre- and postintervention |
EXP: 15 (33) CTL: 5 (0) |
Memory problems: MMI (7 EXP, 3 CTL) MCI (5 EXP, 2 CTL) AD (3 EXP, 0 CLT) |
EXP: 64 (8) CTL: 65 (10) |
EXP: KKYM CTL: listening to classical music Both conditions: 8 weeks, 12-min daily home practice with audio recordings |
Sig. increases on Trails B, WAIS Symbol Substitution Test, and Logical Memory Delayed but not on MMSE, Category Fluency, and Trails A in EXP when not corrected for multiple comparisons. No sig. increases after correction and in CTL |
| Pagnoni et al.77 | CROSSC Two groups | 26 MED: 13 (77) CTL: 13 (77) |
Experienced MED CTL matched for age, sex, education |
MED: 37.2 (6.9) CTL: 35.5 (5.7) |
Zen >3 years’ experience |
Sustained attention sig. decreases with age in CTL but not in MED Gray matter volume sig. decreases in left putamen in CTL but increases in MED |
| Prakash et al.87 | CROSSC Two groups | 40 MED: 20 (100) CTL: 20 (100) |
Mentally healthy Normal cognitive functioning Experienced MED CTL mateched for age, sex, education, SES |
MED: 59.45(3.86) CTL: 60.36(4.51) |
Vihangam yoga meditation, >10 years’ experience (mean 15.90, SD 6.81) | MED performed sig. better than CTL on Digit Span forward, DSST correct, Stroop, Trails A, B, and B-A, LCT total and omission error, RSCT 2, but not on Digit span backward, DSST errors, LCT commission error, and RSCT test time |
| Van Leeuwen et al.81 | CROSSC Three groups | 51 MED: 17 (59) CTL old: 17 (59) CTL young: 17 (41) |
Experienced MED old CTL matched for age, sex, education | MED: 49.8 (5) CTL old: 50 (5.4) CTL young: 24.3 (2.3) |
14 Shamatha Vipashayana (FA, OM) 3 Zen 1–29 years’ experience |
Overall sig. smaller attentional blink in MED than in old CTL and no difference between MED and young CTL Sig. smaller blink in MED than even young CTL at 200 ms lag |
| Jedrczak et al.83 | CROSSC One group | Some tests 150 (57), some 87 (56) | Experienced TM-Sidhi MED | 38.74 (n.r.) | TM (mean 108 months) and TM Sidhi (mean 44 months) | Amount TM Sidhi practice predicted verbal intelligence (WAIS: DSST, PAT) and psychomotor speed (LC and RT but not PMS) |
AD, Alzheimer’s disease; ALS, Associate Learning Scale; CES-D, Center for Epidemiologic Studies Depression Scale; Cond., condition; CROSSC, cross-sectional; CTL, control; CVLT, California Verbal Learning Test; DSST, Digit Symbol Substitution Test; DST, Dementia Screening Test; EXP, experimental; FA, focused attention; FU, follow-up; GDS-12R, Geriatric Depression Scale Residential; HRSD-24, Hamilton Rating Scale for Depression (24 items); LGT, longitudinal; KKYM, Kirtan Kriya yogic meditation (finger tapping, chanting, and brief breathing relaxation along with visualization of light); LC, Line Crossing; LCT, Letter Cancellation Task; MBCT, mindfulness-based cognitive therapy; MBSR, mindfulness-based stress reduction; MCI, mild cognitive impairment; MED, meditation; MF, mindfulness; MFL, mindfulness as defined by Langer;41,42 MMI, mild age-related memory impairment; MMSE, Mini-Mental State Examination; MR, mental relaxation; NR, not randomized; n.r., not reported; NT, no treatment; OM, open monitoring; OVT, Overlearned Verbal Task; PAT, Picture Arrangement Test; PMR, progressive muscle relaxation; PMS, psychomotor speed; PSS, Perceived Stress Scale; RCT, randomized controlled trial; RSCT, Rule Shift Card Test; RT, reaction time; SF-12, Short-Form General Health Survey; TM, transcendental meditation; WAIS, Wechsler Adult Intelligence Scale; WFS, Word Fluency Scale.