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EEG spectral analysis of Shambhavi Mahamudhra practice in Isha Yoga_ A research Study.

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  1. 1. Spatio-Temporal EEG Spectral Analysis of Shambhavi Maha Mudra Practice in Isha Yoga JAYASHREE SANTHOSH, GRACEE AGRAWAL Computer Services Centre, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India E-mail:, MANVIR BHATIA, NANDEESHWARA S.B. Department of Neurology & Clinical Neurophysiology, Sir Ganga Ram Hospital, Rajinder Nagar, New Delhi 110060, India E-mail:, AND SNEH ANAND Centre for Biomedical Engineering, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India E-mail: Abstract: An effort was made to analyze the cerebral electrical activity of nine experienced Isha Yoga practitioners by means of EEG recordings. The EEG data was recorded before and after Shambhavi Maha Mudra practice in Isha Yoga, which is considered to be an antidote to stress. A complete spectral and statistical analysis was done on the data collected to analyze the changes in delta, theta, alpha and beta rhythms. The analysis of the mean relative band power of the data collected after the practice showed a high increase in the delta band power [p<0.05 for F4 & F8] accompanied by an increase in theta band power. There was also a marked decrease in beta band power [p<0.05 for O2, C3 & T3] almost throughout the entire hemisphere and a slight decrease in alpha band power in fronto-parietal and midline brain regions. Furthermore, an increase in coherence between the left and right hemisphere was observed accompanied by a high increase in slow-wave progression [(Delta+Theta)/Alpha] in most of the brain regions. The results clearly show a higher level of mental and lower level of physical consciousness experienced in Shambhavi Maha Mudra Practice in Isha Yoga. Indexing terms: EEG, Band Power, Coherence, Slow-wave Progression, Shambhavi Maha Mudra, Isha Yoga, Consciousness Numerous studies have reported changes in various 1. INTRODUCTION brain rhythms emphasizing the positive effects of Since last many years, research has been conducted meditative state as compared to any type of non- to analyze the effect of meditation on changes in meditative state [5-8]. Most of these studies have human physiology [1-3]. The fact that different indicated an overall slowing down of brain conscious states are accompanied by different rhythms after meditation. However variations in neuro-physiological states and the brain electrical changes of rhythms were also observed between activities measured would reflect these changes different types of meditations. Reasons stated for explains the use of EEG for such studies [4]. such variations were the different techniques used Spatio-temporal patterns of these EEG activities in different types of meditations and specific could be traced to analyze the relation between practices leading to specific changes [9]. meditation and their underlying neuro- physiological changes.
  2. 2. The present study attempts to explore the effect of and Review Software at Sir Ganga Ram Hospital, Shambhavi Maha Mudra in an Isha Yoga program. New Delhi. The filter settings were as: LF 1 Hz, Isha Yoga, known as a powerful method for HF 70 Hz and sampling frequency fixed at 200 Hz. awakening and expanding consciousness, involves 2.3. Experimental Paradigm simple postures and meditation. In their Inner Artifact-free epochs of 3-seconds duration were Engineering program, transmission of the selected from the EEG recordings of each of the Shambhavi Maha Mudra – a powerful process of subjects immediately before and after Shambhavi immeasurable antiquity – is offered to purify the Maha Mudra practice. These recordings were system and improve health, productivity, balance formally called BASELINE1 and BASELINE2 and inner well being [7]. This study analyzes and respectively. The entire procedure was carried out discusses the neuro-physiological changes in a quiet room and took approximately 40 minutes subsequent to this practice using EEG. including preparation of the subject. 2. MATERIALS AND METHODS 2.4. Analysis 2.1. Subjects After computing the Fast Fourier Transform, the Nine healthy experienced Isha Yoga practitioners, absolute band power for prominent EEG spectral (5 F, 4 M) of age between 21 to 36 years (mean = bands (Delta: 1-4 Hz, Theta: 4-8 Hz, Alpha: 8-13 26.1 ± 4.34 years) participated in this research Hz and Beta: 13-30 Hz) was calculated. Following study as subjects. They were all from Isha Yoga this, the relative band power was averaged over all Foundation, Coimbatore with many years of the subjects and is shown in Fig 2. experience (10-11 years) of doing Isha Yoga. The subjects had no history of neurological or psychiatric disorders and none of them were on (a) BASELINE 1 any medication. The experiment paradigm was DELTA THETA ALPHA BETA 0.3 explained fully and written consent was obtained from each of the participants. 0.25 Mean Relative Band Power 2.2. EEG Recordings 0.2 The EEG data was recorded from 19 electrode 0.15 positions on the scalp (FP2, F4, C4, P4, O2, F8, T4, 0.1 T6, FP1, F3, C3, P3, O1, F7, T3, T5, FZ, CZ, PZ) according to the International 10-20 system of 0.05 electrode placement, referenced to the linked ear lobe electrodes. Fig 1 visualizes the montage 0 FP2 F4 C4 P4 O2 F8 T4 T6 FP1 F3 C3 P3 O1 F7 T3 T5 FZ CZ PZ Electrodes showing the electrode placement. (b) BASELINE 2 DELTA THETA ALPHA BETA Fp1 Fp2 0.3 F7 F8 F3 F4 FZ Mean Relative Band Power 0.25 T3 C3 C4 T4 CZ 0.2 PZ P3 P4 0.15 T5 T6 O2 0.1 O1 0.05 Fig 1 Electrode montage 0 FP2 F4 C4 P4 O2 F8 T4 T6 FP1 F3 C3 P3 O1 F7 T3 T5 FZ CZ PZ Electrodes All recordings were done in similar conditions on Fig 2 Mean relative band powers (a) before and (b) various days using Comet XL EEG – A Grass after the practice Telefactor System with AS40 Amplifier system and Windows® based TWin® 3.5a EEG Record
  3. 3. Topographic head maps showing the distribution COHERENCE - BASELINE 2 vs BASELINE 1 of the various brain rhythms on the scalp are DELTA THETA ALPHA BETA 1 *** *** shown in Fig 3, where red depicts the maximum ** ** ** ** and blue depicts the minimum appearance. 0.8 * Change in Coherence Values * * * * 0.6 (a) BASELINE 1 (b) BASELINE 2 0.4 1 1 0.9 0.9 0.2 0.8 0.8 0.7 0.7 0 DELTA THETA DELTA THETA 0.6 0.6 -0.2 0.5 0.5 FP2-FP1 F4-F3 C4-C3 P4-P3 O2-O1 F8-F7 T4-T3 T6-T5 0.4 0.4 Electrode-Pairs 0.3 0.3 Fig 5 Change in coherence values before and after the 0.2 0.2 practice [*p<0.05, **p<0.005, ***p<0.0002] 0.1 0.1 ALPHA BETA ALPHA BETA 0 0 Fig 3 Topographic head maps (a) before and (b) after Change in (DELTA+THETA)/ALPHA Ratio the practice 1 BASELINE 1 (Delta+Theta)/Alpha Mean Band Power Ratio BASELINE 2 0.9 0.8 For comparing the actual changes in various rhythms between the stages, the percentage change 0.7 in mean relative band power before and after 0.6 practice was calculated and is shown in Fig 4. 0.5 0.4 0.3 BASELINE 2 vs BASELINE 1 0.2 DELTA THETA ALPHA BETA 120 Percent Change in Mean Relative Band Power 0.1 100 0 FP2 F4 C4 P4 O2 F8 T4 T6 FP1 F3 C3 P3 O1 F7 T3 T5 FZ CZ PZ 80 Electrodes Fig 6 Change in (Delta+Theta)/Alpha mean band 60 power ratio before and after the practice 40 20 For statistical analysis, one-way repeated measures 0 ANOVA [11] was performed on the log transform -20 (ln) of the absolute EEG band power to test possible differences between the two stages -40 FP2 F4 C4 P4 O2 F8 T4 T6 FP1 F3 C3 P3 O1 F7 T3 T5 FZ CZ PZ Electrodes BASELINE1 and BASELINE2. Fig 4 Percent change in mean relative band power The entire spectral and statistical analysis of the before and after the practice recorded data was carried out using Matlab® 7.0 from The Mathworks Inc., USA. To test the effect of Shambhavi Mahamudra practice on the coherence between the hemispheres, 3. RESULTS the correlation coefficient values were computed Fig 2(a) showing the mean relative band power between corresponding electrodes in both the from the subjects before the Shambhavi Maha hemispheres. Fig 5 shows the change in coherence Mudra practice clearly shows that the alpha band values after the practice, with the significant power is very high at all the electrode positions, changes starred. The progression of slow waves, thus verifying that the Isha Yoga experts had high delta and theta, between the two stages was also levels of relaxation in general. calculated as the ratio of Delta+Theta and Alpha for each electrode location (Fig 6).
  4. 4. As observed in Fig 4, there was a high increase in meditation, the theta activity tends to increase. In the delta band power (delta-F4: p = 0.0128; delta- order to have conscious access to and F8: p = 0.0326) accompanied by an increase in remembrance of the unconscious content, alpha theta band power throughout the entire hemisphere. waves must be present in the EEG. Without alpha, It is to be noted that the simultaneous increase of the unconscious content remains unconscious [13]. these rhythms was maximum along the midline For the present experiment, all subjects showed the brain region. There was also a marked decrease in presence of high alpha power in both the states. beta band power (beta-O2: p = 0.0077; beta-C3: p Delta waves are associated with the deepest states = 0.0452; beta-T3: p = 0.0193) almost throughout of consciousness. Some consider that delta the entire hemisphere and a slight decrease in alpha signifies contact with the collective unconscious. band power in fronto-parietal and midline brain Delta rhythms combined with alpha are known to regions. It was seen that there was a maximum reflect an inner intuitive empathetic radar, a kind decrease in beta rhythm and a maximum increase of sixth sense [13]. It is to be noted that there was a in alpha rhythm in the temporal region marked increase in Delta band power in all simultaneously. subjects after the practice. The changes in coherence between the left and A decrease in alpha power was reported in yogic right hemisphere depicted in Fig 5 clearly shows a meditation and Transcendental Meditation (TM). significant increase in coherence throughout the Also an increased theta, rather than an increase in entire cerebral region after the Shambhavi Maha alpha, was suggestive of proficiency in meditative Mudra practice. A high increase in progression of practice [9]. slow waves was also seen at most of the electrode EEG coherence is understood as a measure of positions (Fig 6). cortical connectivity. Lower values of coherence 4. DISCUSSION & CONCLUSION are associated with white matter lesions and The fundamental assumption that any mental decreased cortical blood flow. Higher values of experience has a corresponding electrical signature coherence have been interpreted as evidence of in the brain, which can be extrapolated from the functional coupling, information exchange or electroencephalogram gave neuroscientists the functional coordination between brain regions. view that mental and neural activities are highly EEG coherence is also thought to be a likely correlated [4]. predictor of other behavioral and physiologic accompaniments of meditation. Some authors have Certain EEG frequency bands were stated to found significant correlation between EEG indicate activity on different hierarchical levels as coherence as clearer experience of pure given in Table 1 [12]. consciousness and higher scores on tests of creativity. Some have also reported correlations between coherence and IQ. Increased frontal TABLE 1: Possible sources of activity in certain EEG frequency bands coherence has been noted in TM, which reflects an enhancement of frontal lobe integration, as Frequency Band Activity increased cognitive flexibility and intelligence and Delta (δ) Higher level of consciousness emotional stability [9]. Theta (θ) Mental consciousness Alpha (α) Physical consciousness In summary, the present experiment results, Beta (β) Specialized regions showing the considerable increase in delta and theta activity in most regions of the brain, indicate Mental tensions, excitement and anxiety cause an that the brain becomes deeply focused following increase in both amplitude and frequency of the Shambhavi Maha Mudra, thus reflecting higher beta rhythms. Alpha waves, which signify level of mental consciousness. The reduction in the conscious awareness, are the bridge to the beta activity signifies lesser anxiety. Above all, the unconscious, which is represented by the lower characteristic changes observed in this experiment frequencies, theta and delta. When one comes established that all subjects showed a specific state close to unconscious memories during deep effect of meditative practice.
  5. 5. 8. S Telles & K V Naveen, Changes in middle REFERENCE latency auditory evoked potentials during 1. Mahesh Yogi, The science of being and art of meditation, Psychological Reports, Vol. 94, living, Penguin Books, New York, 1963. pp. 398-400, 2004. 2. J M Davidson, The physiology of meditation 9. B Rael, Cahn & J Polich, Meditation States and mystical states of consciousness, and Traits: EEG, ERP and Neuroimaging Perspectives in Biology and Medicine, Vol. 19, Studies, Psychological Bulletin, Vol. 132, No. pp. 345-379, 1976. 2, pp. 180-211, 2006. 3. L I Aftanas & S A Golocheikine, Impact of 10. Isha Yoga Foundation. URL: http://www. regular meditation practice on EEG activity at rest and during evoked negative emotions, International Journal of Neuroscience, Vol. 11. A Trujillo-Ortiz, R Hernandez-Walls & R A 115, pp. 893-909, 2005. Trujillo-Perez, RMAOV1: One-way repeated measures ANOVA, 2004. URL 4. P Gloor, Hans Berger on the electroencephalogram of man, EEG Clinical exchange/ Neurophysiology, Vol. 28 (Suppl.), pp. 1-36, 1969. 12. E Jovanov, On methodology of EEG analysis during altered states of consciousness, in D 5. B Anand, G S Chhina & B Singh, Some Rakovic & D Koruga, Eds., Consciousness: aspects of electroencephalographic studies in Scientific Challenge of the 21st century, yogis, Electroencephalography and Clinical ECPD, Belgrade, Yugoslavia, 1995, pp. 227- Neurophysiology, Vol. 13, pp. 452-456, 1961. 242, also available online on 6. K K Deepak, S K Manchanda & M C Maheshwari, Meditation improves 13. E Hoffmann, Mapping the brains activity after clinicoelectroencephalographic measures in Kriya Yoga, Bindu No. 12, Scandinavian drug-resistant epileptics, Biofeedback and Self Yoga and Meditation School, pp. 10-13, 1998. Regulation, Vol. 19, pp. 25-40, 1994. ACKNOWLEDGEMENTS 7. M Bhatia, A Kumar, N Kumar, R M Pandey & V Kochupillai, Electrophysiological The authors acknowledge their gratitude to Isha Evaluation of Sudarshan Kriya: An EEG, Foundation, Coimbatore, Tamil Nadu and BAER, P300 study, Indian Journal of Department of Neurophysiology and WASS Physiology and Pharmacology, Vol. 47, No. 2, (World Academy of Science & Spirituality) at Sir pp. 157-163, 2003. Ganga Ram Hospital, Rajinder Nagar, New Delhi for all the help in conducting the experiment.
  6. 6. AUTHORS Jayashree Santhosh completed She has added many clinical applications for her BTech in Electrical research and clinical service. These include Long- Engineering from University of term monitoring for epilepsy patients, sleep study Kerala, MTech in Computer & (overnight polysomnography), magnetic stimulation Information Sciences from and quantitative sensory evaluation. In addition, Cochin University of Science and she is the Principal Investigator for many projects Technology, Kerala and PhD on sleep studies and magnetic stimulation. She is from IIT Delhi. Presently she is a on the editorial board of International journals and faculty with the Computer Centre, Indian Institute has many publications in National and International of Technology Delhi. journals on topics related to peripheral and central neurophysiology. She has been associated with teaching and various projects with Centre for Bio-Medical Engineering and Department of Biotechnology at Nandeeshwara S.B. has done IIT Delhi and many Continuing Education MBBS from Mysore Medical programmes in the area of Information Technology College, Karnataka. He is now conducted by IIT Delhi. Her research interest working as a Senior Research focuses on Technology Applications in Healthcare Officer in the Dept. of Clinical and is presently working on a project with the Neurophysiology at Sir Ganga Ministry of Social Justice for development of Ram Hospital, Rajinder Nagar, technological interfaces for rehabilitation. She New Delhi. received IETE’s Gowri Memorial Award in 2002- 2003 and IIT-D Alumni Award for Best Technology His research interests are in the field of clinical in 2006. She is fellow member IETE, IAMI and neurology, genetics and oncology. member and present finance secretary for ISB. Sneh Anand did her graduation Gracee Agrawal received the in Electrical Engineering from B.E. degree in Biomedical Thapar College of Engineering Engineering from Manipal and Technology, Patiala in 1970 Institute of Technology, and MTech and PhD from IIT Karnataka, India in June 2006. Delhi in 1976. Since then she She was awarded Gold Medals has been on the faculty of Centre for first rank in the department as for Biomedical Engineering at IIT well as the institute. She is Delhi and AIIMS. Presently she is the head of the currently working as a Project Associate at Indian same center. Institute of Technology Delhi since July 2006. Her principal achievements are in the areas of Her research interests are Biomedical Signal and biomedical sensors with application to Image Processing in the areas of Neuro- physiological diagnostic clinical measurements, engineering and Rehabilitation Engineering. reproductive bioengineering and aids for the disabled. With these and other contributions, she has received several national and international Manvir Bhatia did her DM awards of NRDC, WIPO, ICMR, IETE and Ministry (Neurology) from AIIMS in 1993 of Welfare, Government of India. and has been in-charge of the Clinical Neurophysiology Laboratory at AIIMS from 1993- 2003. Presently she is working as a Senior Consultant in Dept. of Neurology, Sir Ganga Ram Hospital, New Delhi, India.