| Paper authors: | Marlon Danilewitz, Sihaoyu Gao, Mohammad Ali Salehinejad, Ruiyang Ge, Michael Nitsche, Fidel Vila-Rodriguez |
| Year of paper publication: | 2021 |
| Post authors: | Alice Erchov, Sarah Kessler, Fidel Vila-Rodriguez |
| Download the research article: | Danilewitz et al. (2021) Effects of combined yoga and transcranial direct current stimulation intervention on working memory and mindfulness |
Introduction
Yoga and transcranial direct current stimulation (tDCS) have both been shown to improve cognition. Yoga, for example, has been shown to help musculoskeletal conditions, mental health, and our metabolism – with some studies showing it even increases volume in certain areas of the brain (specifically, those involved with feelings and thinking). tDCS, on the other hand, involves placing two electrodes on the scalp that pass a weak electrical current. This current stimulates certain regions of the brain and can change its functioning for the better, over time.
But we don’t know whether tDCS and yoga, when done together, amplify the positive effects of each. This study looked to answer that question.
Methods
- 22 individuals completed a total of 2 study visits. Each visit started with a questionnaire assessing mindfulness and a test that measures working memory
- After these, 11 participants completed “active” tDCS. The other 11 completed “sham” (fake) tDCS, that didn’t use any real stimulation
- This allowed for the experimenters to make sure that the differences between these two groups was because of the inclusion/exclusion of tDCS, and not a placebo (expected) effect
- After either active or sham tDCS, participants completed a 40-minute session of Hatha yoga
- Hatha yoga focuses specifically on physical movement and doesn’t include meditation
- Then, mindfulness and working memory were measured again
Mindfulness
- Mindfulness was measured using a questionnaire that participants filled out
- Questions focused on two main ideas:
- Curiosity measured “an attitude of learning more about one’s experiences”
- Decentering reflected a “distancing from identifying personally with thoughts and feelings related to one’s own experience”
Working Memory
- Working memory refers to the ability to remember one thing while focusing or thinking about something else
- This involved a game where participants were shown one letter at a time on a computer screen
- After several letters, participants were asked to remember what a letter they saw previously was
- For example, participants might be shown A, D, Z, F, V, K and then asked to remember what letter was 3rd from the one shown last was (in this case, the correct answer would be “F”)
Results
- Participants’ accuracy on working memory did not change, regardless of whether or not they received tDCS
- However, reaction time slowed down after receiving tDCS
- Participants had higher levels of mindfulness before yoga, regardless of whether or not they received tDCS
- This was true for both curiosity and decentering
Conclusion
Surprisingly, this study found that combining tDCS and yoga did not have a beneficial effect on either working memory or mindfulness. In fact, mindfulness being higher before yoga/tDCS suggests that the interventions could have, in effect, “cancelled each other out”. However, before being able to make clinically-applicable conclusions, future studies can look to replicate this finding in a bigger group of people and over a longer period of time, which would increase our confidence in these results.