Effect of an 18-Month Meditation Training on Regional Brain Volume and Perfusion in Older Adults: the Age-Well Randomized Clinical Trial.

IMPORTANCE No lifestyle-based randomized clinical trial directly targets psychoaffective risk factors of dementia. Meditation practices recently emerged as a promising mental training exercise to foster brain health and reduce dementia risk. OBJECTIVE To investigate the effects of meditation training on brain integrity in older adults. DESIGN, SETTING, AND PARTICIPANTS Age-Well was a randomized, controlled superiority trial with blinded end point assessment. Community-dwelling cognitively unimpaired adults 65 years and older were enrolled between November 24, 2016, and March 5, 2018, in France. Participants were randomly assigned (1:1:1) to (1) an 18-month meditation-based training, (2) a structurally matched non-native language (English) training, or (3) no intervention arm. Analysis took place between December 2020 and October 2021. INTERVENTIONS Meditation and non-native language training included 2-hour weekly group sessions, practice of 20 minutes or longer daily at home, and 1-day intensive practices. MAIN OUTCOMES AND MEASURES Primary outcomes included volume and perfusion of anterior cingulate cortex (ACC) and insula. Main secondary outcomes included a global composite score capturing metacognitive, prosocial, and self-regulatory capacities and constituent subscores. RESULTS Among 137 participants (mean [SD] age, 69.4 [3.8] years; 83 [60.6%] female; 54 [39.4%] male) assigned to the meditation (n=45), non-native language training (n=46), or no intervention (n=46) groups, all but 1 completed the trial. There were no differences in volume changes of ACC (0.01 [98.75% CI, -0.02 to 0.05]; P=.36) or insula (0.01 [98.75% CI, -0.02 to 0.03]; P=.58) between meditation and no intervention or non-native language training groups, respectively. Differences in perfusion changes did not reach statistical significance for meditation compared with no intervention in ACC (0.02 [98.75% CI, -0.01 to 0.05]; P=.06) or compared with non-native language training in insula (0.02 [98.75% CI, -0.01 to 0.05]; P=.09). Meditation was superior to non-native language training on 18-month changes in a global composite score capturing attention regulation, socioemotional, and self-knowledge capacities (Cohen d, 0.52 [95% CI, 0.19-0.85]; P=.002). CONCLUSIONS AND RELEVANCE The study findings confirm the feasibility of meditation and non-native language training in elderly individuals, with high adherence and very low attrition. Findings also show positive behavioral effects of meditation that were not reflected on volume, and not significantly on perfusion, of target brain areas.