Mild Cognitive Impairment (MCI) is a decline in cognitive performance that is more severe than that of normal aging, yet less severe than that of dementia. Patients with MCI are at risk for developing dementia, and researchers are interested in treatments that can forestall or prevent the progression to dementia onset.

Since mindfulness-based interventions are associated with improvements in attention and increases in brain gray matter cortical thickness, they may be able to help slow or prevent the progression to dementia.

Yu et al. [Journal of Psychiatric Research] compared changes in cognitive functioning and brain cortical thickness in older adults with MCI who participated in either a nine-month mindfulness-based intervention or a control group.

The researchers randomly assigned 54 Singaporean adults (average age=71; 74% female) diagnosed with MCI to either a mindfulness training or health education program. MCI diagnosis was based on subjective reports of cognitive difficulty and a battery of objective neuropsychological tests with final diagnosis made by expert panel consensus. Both interventions met in 45-minute group sessions on a weekly basis for the first 3 months, and then on a monthly basis for the final 6 months of the study.

The mindfulness program included exercises in focused sensory attention, the body scan, walking meditation, and gentle movement meditation. The health education control included didactic instruction on chronic illness, medication compliance, diet, exercise, and relaxation.

Participants were assessed at baseline, 3 months, and 9 months. Assessments included CT scans of the brain and neuropsychological measures of working memory (digit span), divided attention (a trail making task with interference), verbal memory, verbal fluency and, visuospatial processing. CT scans of the brain were evaluated for region of interest changes in gray matter cortical thickness. Regions of interest, including the anterior cingulate cortex, orbitofrontal cortex, frontal pole, and insula, were based on findings from previous mindfulness studies.

Neuropsychological test results at 9 months showed the mindfulness group improved significantly more on cognitive performance than controls (partial η2= 0.44). Subsequent post-hoc analyses showed this superiority was mostly due to improvements in working memory (partial η2= 0.18) and divided attention (partial η2= 0.13). The significance of the post-hoc analyses did not survive correction for multiple tests of significance.

CT scan results at 9 months showed that the mindfulness group showed significantly greater CT scan region of interest increases in cortical thickness (partial η2= 0.67) than controls. Subsequent post-hoc analyses showed this was primarily due to significantly greater increases in right frontal pole (partial η2= 0.21) cortical thickness, and significantly greater decreases in left anterior cingulate cortex cortical thickness (partial η2= 0.21).

The gains in right frontal cortical thickness are consonant with gains in executive cognitive function. The decrease in cingulate cortex cortical thickness was unexpected, but not necessarily a bad outcome as it could reflect reductions in negative emotional reactivity. The significance of these post-hoc analyses did not survive correction for multiple tests of significance.

Reference

Yu, J., Rawtaer, I., Feng, L., Fam, J., Kumar, A. P., Kee-Mun Cheah, I., Honer, W. G., Su, W., Lee, Y. K., Tan, E. C., Kua, E. H., & Mahendran, R. (2021). Mindfulness intervention for mild cognitive impairment led to attention-related improvements and neuroplastic changes: Results from a 9-month randomized control trial. Journal of Psychiatric Research, 135, 203–211.

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