Cerebral Haemodynamic Changes in Type 2 Diabetes Mellitus Following a Three-Month Yoga Intervention: A Randomized Controlled Trial.

Background and purpose Cerebral haemodynamics and cognitive performance may be adversely affected in type 2 diabetes mellitus (T2DM). Previous studies reported reduced cerebral blood flow (CBF) and altered cerebrovascular reactivity (CVR) in T2DM. Yoga, an ancient holistic health approach, is known to be beneficial for T2DM. We hypothesized that yoga practice may alter CBF and the flow resistance in the middle cerebral artery (MCA) and improve cognition in T2DM. Our secondary objective was to explore the relationship between changes in cerebral haemodynamics and cognition in T2DM. Materials and methods Participants were randomly allotted into the yoga and control groups based on the eligibility criteria. One hour of yoga intervention specific to type 2 diabetes was provided to the yoga group for three months, while conventional treatment was provided to the control group. A transcranial Doppler was used to evaluate longitudinal changes in cerebral haemodynamics in MCA. A Corsi block tapping test was used to assess visio-spatial working memory. Results There were 75 participants recruited, of whom 38 participated in yoga and 37 participated in a control group. Both intention to treat and per protocol analysis showed significant results. At day 90, intention-to-treat analysis showed significant changes in CBF velocities (mean difference -10.85%, 95% CI (-13.26, -6.15), p<0.001), cerebral vasodilatory reserve (mean difference -0.23%, 95% CI (-0.43, -0.03), p=0.02) and cognition (mean difference -12.13%, 95% CI (-17.48, -6.78), p≤0.001). There was no between-group effect. Also, the correlation between the CBF and cognition did not show any significant results. Conclusion The three-month yoga intervention was associated with an improvement in cerebral hemodynamics. The study also revealed an improvement in visio-spatial working memory among patients with T2DM. The study did not show any correlation between the improvement in cerebral haemodynamics and working memory. We recommend larger and longer studies on yoga intervention for T2DM patients to evaluate whether such benefits are sustained and improve their quality of life.

Changes in Heart Rate Variability and Executive Functions Following Yoga Practice in Type 2 Diabetes Patients: A Pilot Study.

Context: Type 2 diabetes mellitus (T2DM) patients are at increased risk of cognitive impairment and dementia compared to healthy individuals. Lifestyle practices such as yoga can have a vital role in preventing and managing T2DM. Some studies have found that yoga can positively impact cognitive function in T2DM. Objective: The study aimed to investigate the benefits of short-term yoga practice on heart rate variability (HRV) and cognitive function for T2DM patients, without a matched control group, to address the paucity of data on the effectiveness of yoga practice on cognitive health on T2DM individuals. Design: Current study is a single group pre post design. Setting: The study took place in the Department of Yoga and Life Sciences at Swami Vivekananda Yoga Anusandhana Samsthana (S-VYASA) in Bangalore, India. Participants: Participants were 21 T2DM patients from various hospitals, clinics and community setups, in different parts of Bengaluru city in India. Intervention: The participants took part in one month of yoga practice. Outcome Measures: The research team used the Madrid card sorting test (MCST) to assess participants' executive function (EF) at baseline and postintervention. In addition, the team monitored participants' heart rate variability (HRV) in a resting phase and during task performance. Results: Between baseline and postintervention: (1) participants' reaction time for the MCST decreased for overall task performance (P = .01) and during rule shifting (P = .03); (2) a significant reduction occurred in participants' random errors (REs) and incorrect responses, at P = .02 for both, whereas a significant increase occurred in correct responses and efficient errors (EEs), at P = .03 and P = .01, respectively; (3) the low frequency (LF) and LF/high frequency (HF ) ratio for the HRV decreased; HF increased but the difference wasn't statistically significant; and (4) a statistically significant decrease occurred in LF and LF/HF and an increase in HF occurred during task performance. Conclusion: Yoga therapy had beneficial effects on cognitive performance for the T2DM participants. The yoga practice also positively affected autonomic functions during task performance and suggesting that it can reduce task-induced stress. It's important for the future studies to validate the current findings with a randomized controlled trial.

Prefrontal oxygenation and working memory in patients with type 2 diabetes mellitus following integrated yoga: a randomized controlled trial.

AIMS: Type 2 diabetes mellitus (T2DM) alters brain functional and structural connectivity leading to cognitive dysfunction. This study examined the effect of a 12-week yoga intervention on prefrontal cortex (PFC) oxygenation and working memory in patients with T2DM. METHODS: Fifty participants were randomized into yoga and waitlist control groups. The yoga protocol specific to T2DM was followed. The pre- (day 1), mid- (6 weeks) and post-intervention (12 weeks) assessments included measurement of PFC oxygenation while performing working memory tasks (n-back) using functional near-infrared spectroscopy. RESULTS: Following a 12-week intervention, the yoga group showed improved performance in working memory [accuracy (geometric mean difference of 3.15%, 95% CI [2.33,3.96], p = 0.001) and reaction time (mean difference of 100.8 milliseconds,95% CI [- 166.6, - 35.1], p = 0.002] in the high task load (2-back) associated with higher oxygenation in dorsolateral PFC (ß coefficient mean difference of 95.6, 95% CI [0.23,191], p = 0.049) and ventrolateral PFC (ß coefficient mean difference of 53.4, 95% CI [7.8,98.9], p = 0.018) regions. Higher oxygenation in dorsolateral PFC during 2-back task was positively correlated with accuracy (r(23) = 0.65, p < 0.001) and negatively correlated with reaction time (r(23) = - 0.47,p = 0.017). CONCLUSION: Integrated yoga practice may improve working memory performance associated with higher PFC oxygenation in patients with T2DM. As 12 weeks of yoga intervention improved working memory performance, the regular practice of yoga may have the potential to prevent decline of cognitive functions in clinical conditions.

Transcranial Doppler studies in Type 2 diabetes mellitus: A systematic review.

BACKGROUND: Type II Diabetes mellitus (T2DM) patients are at the risk of developing cerebrovascular diseases, often contributed by altered cerebral haemodynamics. We present a systematic review of studies on cerebral haemodynamics assessment using transcranial Doppler (TCD) in T2DM. REVIEW METHOD: A systematic review of the published articles in the English language between 1991 to 2021. DATA SOURCES: Articles were retrieved via Pubmed and Cochrane library. We included Cross-sectional, prospective, retrospective, randomized controlled, and cross-over studies for this review. RESULTS: A total of 25 articles met the inclusion criteria, which provided data for 3212 patients. CONCLUSION: Cerebral autoregulation is often impaired among patients with T2DM. The risk increased with the duration of T2DM, related complications and presence of comorbidities.