Event-Related Potential Changes Following 12-week Yoga Practice in T2DM Patients: A Randomized Controlled Trial.

Introduction. Type 2 diabetes patients are more likely to experience cognitive decline (1.5%) and dementia (1.6%) than healthy individuals. Although cognitive impairment adversely affects Type 2 diabetes mellitus (T2DM) patients, it is the least addressed complication of T2DM patients. Objective. The present study attempts to examine the changes in cognitive performance of T2DM patients and the probable factors contributing to the changes following 12-week yoga practice. Methods. The current study is a parallel group randomized controlled trial that compared the outcomes of the participants randomized to a yoga group (YG) (n = 25) and to a wait-list control group (n = 29). The study assessed N200 and N450 event-related potential (ERP) components following the Stroop task, heart rate variability (HRV) and HbA1c before and after the intervention. Results. The mean amplitude of the N200 ERP component showed a significant group difference after the intervention, demonstrating an improved neural efficiency in the process of conflict monitoring and response inhibition. No differences were present for the N450 component. T2DM patients showed reduced heart rate and increased mean RR following yoga practice without any corresponding changes in other HRV parameters, demonstrating an overall improvement in cardiac activity. Along with that yoga practice also reduced HbA1c levels in T2DM patients, indicating improved glycemic control. Moreover, HbA1c levels were negatively correlated with reaction time after the intervention, indicating an impact of glycemic control on cognitive performance. Conclusion. The 12-week yoga practice improved cognitive performance by enhancing the processes of conflict monitoring and response inhibition. Further, improved cognitive performance postintervention was facilitated by improved glycemic control.

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.

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.

Heart-brain Rhythmic Synchronization during Meditation: A Nonlinear Signal Analysis.

Background: Heart-brain synchronization is the integration of mind, body, and spirit. It occurs when the electrical activity of the heart and brain is synchronized. In recent years, there has been mounting curiosity to investigate the effects of meditation on heart-brain synchronization with respect to mental and emotional health and well-being. The current investigation aims to explore the rhythmic synchronicity between the brain and the heart during heartfulness meditation (HM) practice. Materials and Methods: The study was performed on 45 healthy volunteers who were categorized into three equal groups: long-term meditators (LTMs), short-term meditators (STMs), and nonmeditators (NMs). The electroencephalogram (EEG) signals were recorded to measure the prefrontal activity, and electrocardiogram (ECG) signals were recorded to measure the cardiac activity. The data were recorded in four states: baseline, meditation, transmission, and posttransmission. The detrended fluctuation analysis (DFA) method was used for the analysis of EEG and ECG signals. Results: The result indicates that DFA values of EEG and ECG declined during meditation and transmission states as compared to pre- and postmeditation states. Significant results were obtained for the LTM group in all the states. A positive correlation was also observed between DFA of the heart and brain for the LTM group and no significant correlations were observed for the STM and NM groups. Conclusion: The shreds of evidence suggest that heart-brain synchronization facilitates mental and emotional stability. HM practice has the potential to regulate the fluctuation of the mind. Regular meditation practice may result in physiological synchrony between cardiac and neural behavior, which can be considered a quality index for meditation practice.

Comparative Cross-sectional Study on Phasic Heart Rate Variability and Working Memory Among Young Adults.

Context: Heart rate variability (HRV) could be a promising early biomarker of cognitive impairment. A better understanding of reaction patterns between cardiovascular and cognitive functions can be helpful in predicting and preventing the manifestation of disease. Additionally, beneficial cardiovascular evidence for yoga is promising but lacks short-term (approximately one year) cross-sectional investigations. Objective: The study intended to investigate phasic HRV and its patterns of reaction in yoga practitioners and nonpractitioners, using rest and stress periods induced by cognitive tasks. Design: The research team designed a cross-sectional, controlled study. Setting: The study took place in the Cognitive Neuroscience Laboratory at Swami Vivekananda Yoga Anusandhana Samsthana (S-VYASA) in Bangalore, Karnataka, India. Participants: Participants were 84 healthy male volunteers, 42 in the yoga group, the intervention group, and 42 in the nonyoga group, the control group. Outcome Measures: Simultaneously the research team recorded both an autonomic measurement, an electrocardiogram (EKG), and a working memory (WM) task, the N-back task, to assess the effects of the two groups' reaction patterns on HRV and WM. The data included an average of a 5 min epoch for the baseline EKG and a 15 min epoch for the EKG during the N-back task. The research team recorded the HRV indices: (1) mean rhythm-to-rhythm (RR) intervals, (2) heart rate (HR), (3) standard deviation of RR intervals (STDRR), (4) root mean square of successive differences (RMSSD), (5) triangular interpolation of RR interval histogram (TINN), (6) percentage of successive normal sinus RR intervals >50 ms (pNN50), (7) number of adjacent N-N intervals over 50 ms (NN50), (8) low frequency (LF), (9) high frequency (HF), and (10) LF/HF ratio. The team compared the HRV indices to participants' reaction patterns while performing cognitive tasks. Results: In response to psychological stress, the yoga group had enhanced physiological activity, such as an increased cardiac activity, indicated during the task by a higher HR, NN50, and TINN and a lower RR, STDRR, pNN50, and RMSSD, indicating more flexibility. The control group had an increase only in HR and TINN and had a decreased RR. Simultaneously, the yoga group showed greater accuracy in the N-back task for WM compared to the control group. Conclusions: The study revealed significant differences in phasic HRV and WM performance among the groups. The yoga group had higher phasic HRV indices with higher cognitive performance than the control group. This is the first study that has attempted to show that the cross-sectional differences in HRV indices between yoga practitioners and nonpractitioners exist at an early stage of life, where no disease has yet manifested. The research team suggest that incorporating yoga into daily life at a young age may yield a healthy life.

Slow yoga breathing improves mental load in working memory performance and cardiac activity among yoga practitioners.

This study investigated the immediate effect of slow yoga breathing (SYB) at 6 breaths per minute (bpm) simultaneously on working memory performance and heart rate variability (HRV) in yoga practitioners. A total of 40 healthy male volunteers performed a working memory task, 'n-back', consisting of three levels of difficulty, 0-back, 1-back, and 2-back, separately, before and after three SYB sessions on different days. The SYB sessions included alternate nostril breathing (ANB), right nostril breathing (RNB), and breath awareness (BAW). Repeated measures analysis of variance showed a significant reduction in reaction time (ms) in 2-back condition immediately after ANB (-8%), RNB (-8%) and BAW (-5%) practices. Similarly, the accuracy was improved in the 0-back condition after RNB (4%), and in the 2-back condition after ANB (6%) and RNB (6%) practices. These results suggest that SYB practice enhances cognitive abilities (8-9%) related to memory load and improves the functioning of cardiac autonomic activity, which is required for the successful completion of mental tasks.Trial registered in the Clinical Trials Registry of India (CTRI/2018/01/011132).

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.

Heartfulness Meditation Alters Electroencephalogram Oscillations: An Electroencephalogram Study.

Background: Heartfulness meditation (HM) has been shown to have positive impacts on cognition and well-being, which makes it important to look into the neurophysiological mechanisms underlying the phenomenon. Aim: A cross-sectional study was conducted on HM meditators and nonmeditators to assess frontal electrical activities of the brain and self-reported anxiety and mindfulness. Settings and Design: The present study employed a cross-sectional design. Methods: Sixty-one participants were recruited, 28 heartfulness meditators (average age male: 31.54 ± 4.2 years and female: 30.04 ± 7.1 years) and 33 nonmeditators (average age male: 25 ± 8.5 years and female: 23.45 ± 6.5 years). An electroencephalogram (EEG) was employed to assess brain activity during baseline (5 min), meditation (10 min), transmission (10 min) and post (5 min). Self-reported mindfulness and anxiety were also collected in the present study. The EEG power spectral density (PSD) and coherence were processed using MATLAB. The statistical analysis was performed using an independent sample t-test for trait mindfulness and anxiety, repeated measures analysis of variance (ANOVA) for state mindfulness and anxiety, and Two-way multivariate ANOVA for EEG spectral frequency and coherence. Results: The results showed higher state and trait mindfulness, P < 0.05 and P < 0.01, respectively, and lower state and trait anxiety, P < 0.05 and P < 0.05, respectively. The PSD outcomes showed higher theta (P < 0.001) and alpha (P < 0.01); lower beta (P < 0.001) and delta (P < 0.05) power in HM meditators compared to nonmeditators. Similarly, higher coherence was found in the theta (P < 0.01), alpha (P < 0.05), and beta (P < 0.01) bands in HM meditators. Conclusions: These findings suggest that HM practice may result in wakeful relaxation and internalized attention that can influence cognition and behavior.

Yoga-Based Relaxation Technique Facilitates Sustained Attention in Patients with Low Back Pain: A Pilot Study.

CONTEXT: The experience of pain strongly influences sustained attention, which is important for neurocognitive performance. Yoga-based relaxation techniques may be effective in improving sustained attention by attenuating pain in patients with low back pain. Hence, we aimed to investigate the effect of a yoga-based relaxation technique on sustained attention and self-reported pain disability in patients with low back pain. METHODS: A total of 22 men aged 30 to 50 years with low back pain were recruited for the study. They were randomly assigned to either the yoga (n = 11) or control (n = 11) groups. The yoga group practiced a yoga-based relaxation technique (YBRT) 1 hour a day for 4 weeks and the control group maintained their usual physical activity regimen. Assessments included the Sustained Attention to Response Task (SART) and the Oswestry Low Back Pain Disability Questionnaire (OLBPDQ) measured before and after the 4-week intervention. RESULTS: The study showed a significant reduction in all self-reported OLBPDQ domains and improvement in sustained attention in a before and after comparison 4 weeks following the yoga intervention. Pearson's correlation also showed a positive correlation between sustained attention and pain reduction following the yoga intervention. CONCLUSION: The findings indicate that yoga practice reduces pain and simultaneously improves information processing speed with impulse control during the performance of a sustained attention task.

Changes in Lung Function Measures Following Bhastrika Pranayama (Bellows Breath) and Running in Healthy Individuals.

BACKGROUND: The purpose of this study was to observe the effect of bhastrika pranayama (bellows breath) and exercise on lung function of healthy individuals. MATERIALS AND METHODS: A total of thirty male participants were recruited and randomly divided into two groups, i.e., yoga breathing group (YBG, n = 15) and physical exercise group (PEG, n = 15), and the participants' ages ranged between 18 and 30 years (group age mean ± standard deviation, 22.5 ± 1.9 years). YBG practiced bhastrika pranayama for 15 min, whereas PEG practiced running for 15 min, 6 days in a week, over a period of 1 month. The participants were assessed for (i) forced vital capacity (FVC), (ii) forced expiratory volume in the first second (FEV1), (iii) peak expiratory flow rate (PEFR), and (iv) maximum voluntary ventilation (MVV) functions of lungs. RESULTS: Repeated-measures analyses of variance with Bonferroni adjustment post hoc analyses of multiple comparisons showed that there was a significant increase in YBG for all variables, i.e., FVC, FEV1, PEFR, and MVV (P < 0.001, P < 0.001, P < 0.01, and P < 0.001, respectively), whereas there was a significant increase in PEFR and MVV (P < 0.05 and P < 0.01, respectively) only, among PEG. However, the change in PEG was less of magnitude as compared to YBG. CONCLUSIONS: These findings demonstrate that incorporating pranayama in sports can enhance the efficiency of healthy individuals and athletes by enhancing the ventilatory functions of lungs, especially for those who partake in aerobic-based sports and require efficient lungs to deliver sufficient oxygen uptake.

Evolution from four mental states to the highest state of consciousness: A neurophysiological basis of meditation as defined in yoga texts.

This chapter provides a theoretical introduction to states of consciousness and reviews neuroscientific investigations of meditation. The different states of consciousness consist of four mental states, i.e., cancalata (random thinking), ekagrata (non-meditative focusing), dharna (focused meditation), and dhyana (meditation) as defined in yoga texts. Meditation is a self-regulated mental process associated with deep relaxation and increased internalized attention. Scientific investigations on meditation reported changes in electrophysiological signals and neuroimaging measures. But most outcomes of meditation studies showed inconsistent results, this may be due to heterogeneity in meditation methods and techniques evolved in the last 200 years. Traditionally, the features of meditation include the capacity to sustain a heightened awareness of thoughts, behaviors, emotions, and perceptions. Generally, meditation involves non-reactive effortless monitoring of the content of experience from moment to moment. Focused meditation practice involves awareness on a single object and open monitoring meditation is a non-directive meditation involved attention in breathing, mantra, or sound. Therefore, results of few empirical studies of advanced meditators or beginners remain tentative. This is an attempt to compile the meditation-related changes in electrophysiological and neuroimaging processes among experienced and novice practitioners.

Effect of Yoga Based Lifestyle Intervention on Patients With Knee Osteoarthritis: A Randomized Controlled Trial.

Objective: To investigate the effect of integrated approach of yoga therapy (IAYT) intervention in individual with knee Osteoarthritis. Design: Randomized controlled clincial trail. Participants: Sixty-six individual prediagnosed with knee osteoarthritis aged between 30 and 75 years were randomized into two groups, i.e., Yoga (n = 31) and Control (n = 35). Yoga group received IAYT intervention for 1 week at yoga center of S-VYASA whereas Control group maintained their normal lifestyle. Outcome measures: The Falls Efficacy Scale (FES), Handgrip Strength test (left hand LHGS and right hand RHGS), Timed Up and Go Test (TUG), Sit-to-Stand (STS), and right & left extension and flexion were measured on day 1 and day 7. Results: There were a significant reduction in TUG (p < 0.001), Right (p < 0.001), and Left Flexion (p < 0.001) whereas significant improvements in LHGS (p < 0.01), and right extension (p < 0.05) & left extension (p < 0.001) from baseline in Yoga group. Conclusion: IAYT practice showed an improvement in TUG, STS, HGS, and Goniometer test, which suggest improved muscular strength, flexibility, and functional mobility. CTRI Registration Number: http://ctri.nic.in/Clinicaltrials, identifier CTRI/2017/10/010141.

Influence of Yoga-Based Personality Development Program on Psychomotor Performance and Self-efficacy in School Children.

Selective attention and efficacy are important components of scholastic performance in school children. While attempts are being made to introduce new methods to improve academic performance either as part of curricular or extracurricular activities in schools, the success rates are minimal. Hence, this study assessed the effect of yoga-based intervention on psychomotor performance and self-efficacy in school children. Two hundred ten school children with ages ranging from 11 to 16 years (mean age ± SD; 13.7 ± 0.8 years) satisfying the inclusion and exclusion criteria were recruited for the 10-day yogä program. An equal number of age-matched participants (n = 210; mean ± SD; 13.1 ± 0.8 years) were selected for the control group. Participants were assessed for attention and performance at the beginning and end of 10 days using trail making task (TMT) A and B, and self-efficacy questionnaire. The yoga group showed higher self-efficacy and improved performance after 10 days of yoga intervention. The performance in TMT-A and -B of the yoga group showed a significantly higher number of attempts with a reduction in time taken to complete the task and a number of wrong attempts compared with control group. Results suggest that yoga practice enhances self-efficacy and processing speed with fine motor coordination, visual-motor integration, visual perception, planning ability, and cognitive performance.

Long Latency Auditory Evoked Potentials during Meditation.

The auditory sensory pathway has been studied in meditators, using midlatency and short latency auditory evoked potentials. The present study evaluated long latency auditory evoked potentials (LLAEPs) during meditation. Sixty male participants, aged between 18 and 31 years (group mean±SD, 20.5±3.8 years), were assessed in 4 mental states based on descriptions in the traditional texts. They were (a) random thinking, (b) nonmeditative focusing, (c) meditative focusing, and (d) meditation. The order of the sessions was randomly assigned. The LLAEP components studied were P1 (40-60 ms), N1 (75-115 ms), P2 (120-180 ms), and N2 (180-280 ms). For each component, the peak amplitude and peak latency were measured from the prestimulus baseline. There was significant decrease in the peak latency of the P2 component during and after meditation (P<.001; analysis of variance and post hoc analysis with Bonferroni adjustment). The P1, P2, and N2 components showed a significant decrease in peak amplitudes during random thinking (P<.01; P<.001; P<.01, respectively) and nonmeditative focused thinking (P<.01; P<.01; P<.05, respectively). The results suggest that meditation facilitates the processing of information in the auditory association cortex, whereas the number of neurons recruited was smaller in random thinking and non-meditative focused thinking, at the level of the secondary auditory cortex, auditory association cortex and anterior cingulate cortex.

Hemodynamic responses on prefrontal cortex related to meditation and attentional task.

Recent neuroimaging studies state that meditation increases regional cerebral blood flow (rCBF) in the prefrontal cortex (PFC). The present study employed functional near infrared spectroscopy (fNIRS) to evaluate the relative hemodynamic changes in PFC during a cognitive task. Twenty-two healthy male volunteers with ages between 18 and 30 years (group mean age ± SD; 22.9 ± 4.6 years) performed a color-word stroop task before and after 20 min of meditation and random thinking. Repeated measures ANOVA was performed followed by a post hoc analysis with Bonferroni adjustment for multiple comparisons between the mean values of "During" and "Post" with "Pre" state. During meditation there was an increased in oxy-hemoglobin (ΔHbO) and total hemoglobin (ΔTHC) concentration with reduced deoxy-hemoglobin (ΔHbR) concentration over the right prefrontal cortex (rPFC), whereas in random thinking there was increased ΔHbR with reduced total hemoglobin concentration on the rPFC. The mean reaction time (RT) was shorter during stroop color word task with concomitant reduction in ΔTHC after meditation, suggestive of improved performance and efficiency in task related to attention. Our findings demonstrated that meditation increased cerebral oxygenation and enhanced performance, which was associated with activation of the PFC.