Table 1 Characteristics of included studies.

From: RETRACTED ARTICLE: Mindfulness-based randomized controlled trials led to brain structural changes: an anatomical likelihood meta-analysis

Study

Subject

Intervention details

Author, year

Country

Age: mean (SD)

Education, in years: mean (SD)

Clinical status

Type of mindfulness practice

Length of intervention

Type of randomization

Type of control group

Sample size (female)

Grey matter volume

 48

China

IG: 21.83 (2.48)

IG: 16.33 (2.23)

Healthy

TCC

8 weeks, 3 1 h sessions per week

Random

PCG: TAU

IG: 12 (10)

PCG: 21.75 (2.45)

PCG: 16.33 (1.50)

ACG: Aerobic exercise

PCG: 12 (10)

ACG: 21.92 (2.28)

ACG: 16.41 (2.27)

ACG: 12 (10)

 49

Italy

IG: 21.63 (2.02)

Not available, university students

Healthy

Sahaja yoga meditation

4 weeks, 1 1 h session per week

Random

PCG: waitlist

IG: 12 (2)

PCG: 22.16 (1.33)

PCG: 30 (12)

 50

India7

IG: 67.00 (1.00)1

IG: 15.00 (0.75)1

Clinical criteria for aMCI or probable AD

Full body relaxation, meditation on peace, witnessing the breath, witnessing of thoughts

2 weeks, 4 sessions guided and 6 months, daily 30 min at home

Quasi-random

PCG: TAU2

IG: 11 (4)

PCG: 71.00 (3.25)1

PCG: 14.00 (0.88)1

PCG: 11 (5)

 51

Canada

IG: 48.36 (12.82)

Not available

Breast cancer survivors suffering from chronic neuropathic pain

MBSR

8 weeks, 1 2.5 h session per week and 1 full day session

Random

PCG: waitlist

IG: 13 (13)

PCG: 56.50 (8.11)

PCG: 10 (10)

 52

US

IG: 38.00 (4.10)

IG: 17.70 (1.90)

Healthy

MBSR

8 weeks, 1 2.5 h session per week and 1 full day session

Quasi-random3

PCG: waitlist

IG: 16 (10)

PCG: 39.00 (9.20)

PCG: 17.30 (1.80)

PCG: 17 (6)

 53

US

IG: 60.90 (6.66)4

IG: 15.70 (2.06)4

At-risk for AD

Yoga

12 weeks, 1 1 h session per week guided and daily 12 min recording at home

Random

ACG: Memory enhancement training

IG: 11 (11)

ACG: 64.00 (6.48)4

ACG: 16.1 (1.66)4

ACG: 11 (11)

 54

China

IG[1]: 62.181

IG[1]: 9.061

Healthy

IG[1]: Baduanjin

12 weeks, 5 1 h session per week

Random

ACG: Basic health education and usual physical activity

IG[1]: 16 (10)

IG[2]: 60.311

IG[2]: 9.611

IG[2]: TCC

IG[2]: 21 (13)

ACG: 60.161

ACG: 8.371

ACG: 24 (18)

 55

China

IG: 65.79 (4.35)4

Not available

MCI

Baduanjin

24 weeks, 3 1 h session per week

Random

PCG: physical activity as usual

IG: 205

PCG: 65.86 (5.28)4

ACG: brisk walking

PCG: 205

ACG: 64.88 (3.30)4

ACG: 205

Cortical thickness

 56

Italy

IG: 31.00 (4.00)

Not available

Healthy

MBSR

8 weeks, 1 2.5 h session per week and 1 full day session

Random

PCG: waitlist

IG: 23 (12)

PCG: 30.00 (4.00)

PCG: 22 (11)

 57

Germany

IG: 41.254

Not available

Healthy

Breathing meditation and body scan, loving-kindness meditation and affect dyad, observing-thoughts meditation and perspective dyad

39 weeks, 1 2 h session per week6

Random

PCG: matched retest control

IG: 127 (95)4

PCG: 40.004

PCG: 72 (53)4

 58

Singapore

IG: 71.30 (5.60)4

IG: 5.20 (4.90)4

MCI

Mindfulness awareness programme (mindfulness of the senses, body scan, walking meditation, moving with awareness, mind–body coordination)

3 months, 1 45 min session per week

Random

ACG: health education programme

IG: 20 (19)4

ACG: 71.40 (6.00)4

ACG: 3.40 (4.30)4

ACG: 18 (21)4

  1. SD standard deviation, IG intervention group, PCG passive control group, ACG active control group, TCC Tai Chi Chuan, TAU treatment as usual, aMCI amnestic mild cognitive impairment, AD Alzheimer’s disease, MBSR mindfulness-based stress reduction, US United States.
  2. 1SD was not provided and if range was provided, the range rule, whereby the SD of the sample is approximately 1/4th the range of the data, is used to estimate it.
  3. 2Authors combined the ACG that did a colouring task with the PCG because of high dropout rates.
  4. 3This was assumed from the study’s methods as it was not explicitly stated.
  5. 4These demographic variables were not based on the final sample but the sample at baseline.
  6. 5Number of females in the final sample with usable MRI scans were not known.
  7. 6Intervention protocol involves multiple training modules and has been simplified here for clarity’s sake. Please refer to the paper for more details.
  8. 7This study had both grey matter volume and cortical thickness data.
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