Let me state my biases right upfront, I am a yoga practitioner, so I may have a tendency to be less critical of yoga positive research. With that in mind, let me report on this study published in The Journal of Alzheimer’s Disease: “Changes in Neural Connectivity and Memory Following a Yoga Intervention for Older Adults: A Pilot Study.” Here is the abstract:
No study has explored the effect of yoga on cognitive decline and resting-state functional connectivity.
This study explored the relationship between performance on memory tests and resting-state functional connectivity before and after a yoga intervention versus active control for subjects with mild cognitive impairment (MCI).
Participants ( ≥ 55 y) with MCI were randomized to receive a yoga intervention or active “gold-standard” control (i.e., memory enhancement training (MET)) for 12 weeks. Resting-state functional magnetic resonance imaging was used to map correlations between brain networks and memory performance changes over time. Default mode networks (DMN), language and superior parietal networks were chosen as networks of interest to analyze the association with changes in verbal and visuospatial memory performance.
Fourteen yoga and 11 MET participants completed the study. The yoga group demonstrated a statistically significant improvement in depression and visuospatial memory. We observed improved verbal memory performance correlated with increased connectivity between the DMN and frontal medial cortex, pregenual anterior cingulate cortex, right middle frontal cortex, posterior cingulate cortex, and left lateral occipital cortex. Improved verbal memory performance positively correlated with increased connectivity between the language processing network and the left inferior frontal gyrus. Improved visuospatial memory performance correlated inversely with connectivity between the superior parietal network and the medial parietal cortex.
Yoga may be as effective as MET in improving functional connectivity in relation to verbal memory performance. These findings should be confirmed in larger prospective studies.
Interesting, but I do have a few concerns. The improvement in depression for the yoga group was statistically significant but the effect size was small:
the yoga group improved significantly in depression (GDS) and in visuospatial memory (Rey-O delayed recall). The clinical improvement in GDS for the yoga group was only minimal (baseline 7.5 (5.1) and follow up 3.9 (2.5); p = 0.01).
If you look at the table you will see that the control group also experience a reduction in depression, the fact that it did not achieve significant is likely an artifact of the study’s small sample size. Moreover, the yoga group started out with much higher depression scores suggesting that the groups might not have been comparable.
Here is the authors’ descriptions of the study’s limitations:
The sample size was only powered towards rs-fMRI findings, and exploring relationships between memory and functional connectivity, not exploring multi-domain effects on cognition. Additionally, we do not have long-term follow-up, which means we are unable to explore cognitive decline towards dementia. Also, it is possible that the enhanced cognitive benefits and connectivity changes resulting from the KK yogic intervention were due to the 60 min of instruction per week, the 12 min per day of Kirtan kriya meditation (shown to positively affect blood flow in the brain ), or a combination of these factors. However, as previous studies only using KK meditation found activation patterns that are in-line with those from the present research, it is unlikely that the weekly classes presented a large deviation. Nevertheless, this is a fruitful area for future research studies, which may aim to parse out the effects of these various activities, or perhaps determine that for optimal benefits weekly classes in addition to a daily meditative practice is recommended.