Posted 09.27.2018 | by AMRA

Meditation practice reliably demonstrates beneficial effects for memory, attention, mood, and emotional regulation. It is unclear, however, whether there is a minimum dosage necessary to attain these benefits.

Basso et al. [Behavioural Brain Research] measured the benefits of meditation in a group of meditation-naïve participants by assigning them to either daily brief guided meditations or to a control group, and measuring their changes in mood and cognition over time.

The researchers randomly assigned 72 meditation-naïve participants to either a meditation audio or a podcast audio. The meditation group listened to 13-minute guided meditations daily for 8 weeks. The meditations included breath-focused exercises and a body scan practice. The podcast group listened to 13-minute excerpts from NPR’s Radiolab podcast daily for 8 weeks.

Participants underwent neuropsychological and psychological evaluations and salivary cortisol (a stress hormone) assessments at baseline, 4 weeks, and 8 weeks. Computer-administered neuropsychological tests included measures of attention, working and recognition memory, and response inhibition. The psychological tests measured mindfulness (Mindful Attention Awareness Scale or MAAS), mood, stress, depression, anxiety, rumination, sleep quality, fatigue, quality of life, self-esteem, and life satisfaction.

Following the final assessments, participants were subjected to a stress-inducing task. They were told to prepare for a job interview and deliver a five-minute presentation on why they should be hired in front of two stone-faced judges. They were then told to perform a difficult serial subtraction problem. Whenever they made an arithmetic mistake, they were instructed to start the problem over from the beginning.

Subjective measures of anxiety were taken at baseline, immediately after, and at 10, 20, and 30-minute intervals after the stress-inducing tasks. Salivary cortisol levels were also assessed at each of these time points.

The study had a significant attrition rate: 45% of the participants either dropped out or were excluded due to insufficient participation. The final sample included 42 participants (15 male, 27 female).

There were no differences between the groups at baseline or 4 weeks. At 8 weeks, meditators showed better mood (partial η2 = 0.11) (especially reduced anger, hostility, bewilderment, and confusion), less anxiety (η2 = 0.10), and less fatigue (η2 = 0.15) than controls. Meditators also displayed better working memory (η2=0.11) and recognition memory (η2=0.10), and made more correct responses on congruent Stroop task trials (η2 = 0.12) than controls.

On the other hand, controls showed improved sleep quality over time, while meditators did not (η2 = 0.18). Meditators reported experiencing less anxiety during the stress-inducing tasks (η2 = 0.10). Meditation participants who showed the largest improvement in mood also showed the least anxiety in response to the stress-inducing task (r = -0.41). There were no measurable effects on cortisol levels.

The study showed that 8 weeks of daily brief meditation measurably improves mood, anxiety in response to stress, and aspects of attention and memory. The study also showed that 4 weeks of practice were not sufficient to yield results. This suggests that meditative effects are cumulative and only emerge with repeated practice over time.

The study was limited by its high attrition rate. Additionally, the fact that the interventions did not differentially affect mindfulness scores makes it unclear whether the mood and cognitive benefits were actually attributable to changes in mindfulness.

Reference:

Basso, J. C., McHale, A., Ende, V., Oberlin, D. J., & Suzuki, W. A. (2018). Brief, daily meditation enhances attention, memory, mood, and emotional regulation in non-experienced meditators. Behavioural Brain Research.

[Link to abstract]