Indian J Physiol Pharmacol 2000; 44 (2) : 173-178

A STUDY OF ELECTROENCEPHALOGRAM IN MEDITATORS

K. C. KHARE* AND SHASHI KANT NIGAM

Department of Medicine,M.G.M. Medical College and M.Y Group of Hospitals,Indore - 452 001 (MP)

(Received on October 22, 1999)

Abstract: Electroencephalographic patterns were studied in 30 normalhealthy individuals practicing meditation and compared with 10 normalhealthy controls not practicing meditation. In this study, we foundprominent alpha wave activity and increase it its voltage in meditators ascompared to controls.

Meditators had significantly more alpha rhythm as compared to controlgroup. Percentage of alpha waves were higher in persons performingmeditation with good coherence which suggested good homogenecity,uniformity and increased order.liness of brain.

Key words: meditation

INTRODUCTION

Stress and' strain of modern life can bereduced either by relaxing or by meditation.Relaxation can be done by sleep, seeingfilms, reading interesting novels, etc.However, the effect of such methods is shortlived. Complete mental and physicalrelaxation is possible by ancient procedurese.g. Yogic meditation and transcendentalmeditation.

Several investigators have noted EEGchanges in the normal adults practisingYoga meditation. Das and Gu st eu t (1)recorded the fast frequency waves duringdeep states of meditation. Anand et al (2)pointed out prominence of alpha activityassociated with absence of reaction ofexternal stimuli to patients practicing KriyaYoga meditation. Wallace (3) observed theappearance of Theta waves in frontal area

EEG alpha waves

during practicing of transcendentalmeditation. Banquet (4) studied spectralanalysis of EEG in transcendentalmeditators. Kothari and Bordia (6) reportedstudy on a Yogi during eight daysconfinement in a sealed underground pit.They studied EEG and ECG in this Yogi.

There are three major types ofmeditation:

1. Yogic meditation.

2. American transcendental meditation.

3. Zen meditation or Zazen.

Yogic meditation is a type of meditationwhere concentration IS done andsubsequently person goes into meditation,this is also called Yogic Kriya YogaMeditation or Astyang Yoga Meditation.While transcendental meditation is a typeof meditation which is of relaxation type

*Corresponding Author

174 Khare and Nigam

and is different from yogic meditation. InZazen, attention is focussed on breathe orlogically challenging riddle called a Kaon.All forms of meditation require physicalimmobility.

Studies therefore were undertaken toin ves ti ga te E lectoencephalographicalactivity of brain during yogic meditation andtranscendental meditation. The presentwork has been the subject of preliminarypresen ta tion of EEG in two types ofmeditation at this centre.

METHODS

The study was conducted In 30 casespracticing meditation at M.G.M. MedicalCollege, Indore. All cases were in age groupranging from 17 to 66 years and all weremales. They were divided into two groupscomprising of 15 cases in each group.

1. Meditator group

1. Those practicing transcendentalmeditation. All were males (15 cases).

11. Those practicing yogic meditation.All were males (15 cases).

2. Control group

Comprised of 10 cases of similar age andsex matched who were not meditating anytime. Both the groups were takingvegetarian diet only. All meditators weredoing their practice for a period of 3 months.The pres en t study was performed inmeditators as:

1. EEG before meditation.

11. EEG during meditation.

iii. EEG after meditation.

Whereas in control group, EEG wast ak en before and during eye closedrelaxation and after relaxation.

Indian J Physiol Pharmacol 2000; 44(2)

The examination during meditationincluded:

1. Electroencephalograms (EEG) wererecorded with Grass Instrument Co.Quincy Mass (USA). Electroence-phalograph model 8, manufactured byGrass Instrument Co. The EEG traceswere recorded on ink paper. The skinelectrodes were placed according tointernational 10-20 system at FPl, FP2,F3, F4, C3, P3, P4, 01, 02. GrassInstrument Company plated cup.electrodes and EEG electrode cream wasapplied. Recording were bipolar.

The EEG, was analyzed for alphafrequency, alpha voltage, alpha percentage,alpha coherence and hemisphere symmetryIn both control and meditative subjects.

EEG was studied by two differentpersons who were unaware of the subjects.

Planning was as follows:

1. Eye closed relaxation for 2 min and EEGwas recorded during which eye openresponse was also noted.

2. During meditation EEG was recorded atevery 5 min. interval while control wereasked to relax as much as during thisperiod (20 minutes).

3. Photic Stimulation response was alsonoted during meditation and controlcases.

4. After the period of meditation was over,subjects were asked to relax for 2 rmn .and then eye open response wasrecorded.

EEG tracings were recorded on paperand then stored on analogue data on tapeand they were converted to digital data bya system data computer. These digital data

176 Khare and Nigam Indian J Physiol Pharmacol 2000; 44(2)

TABLE III: Showing alpha percentage in frontal area in cases(TM) and Controls and effect of meditation.

Study group Control

Mean ± S.D. Mean ± S.D.

Before R: 58.4 24.04 33.00 13.60L: 61.58 23.74 34.34 19.35

During R: 68.78 19.33 28.79 28.49L: 66.72 19.66 28.16 29.01

P-ualue

< 0.01< 0.01< 0.001< 0.001

Before

TABLE IV: Showing coherence before and during meditation.

During't' 'P'

Mean ± S.D. Mean ± S.D.

Study group 8.343.01 <.005

12.79

Control 13.42 5.35

TABLE V: Showing mean R/L alpha amptitudebefore and during meditation in 'I'Mand contros.

Before During

Meditators (TM)

Controls0.8441.027

0.8761.003

3. In this study, there was no evidence oftheta waves in meditator group as wellas in control group.

4. Eye opening response: Meditators showedpersistence of alpha waves after eyeopening in 28.9% of cases, as comparedto mean alpha wave 12.4% in controlcases.

5. Coherence: In meditators good coherencewas recorded during meditation. Theinterhemispheric time difference inalpha frequency was 12.79 ± 8.34milliseconds which becomes 8.75±5.65indicating good coherence (Table IV).

6. Hemispherical symmetry: Right andleft voltage ratio which was 0.844before meditation became 0.876 duringmeditation. Which suggested goodsymmetry in both hemisphere (Table V).

8.75 5.65

12.76 6.75

7. Photic stimulation: No difference wasobserved in meditators and control groupin EEG.

8. Cardio-respiratory parameter: Showedthat pulse and heart rate sloweddown in meditators groups. Respiratoryrate also became less in grouppracticing meditation. Blood pressureshowed fall of systolic bloodpressure only. There was no changein diastolic blood pressure. ECG didnot reveal any abnormal tracing inthem.

DISCUSSION

The alpha waves are suggestiveof increased relaxed state of mind.Alpha voltage in inversely related tomental activity. Increase in voltageis accompanied by decrease in the frequencywhich occurs due to decrease in brainactivity. Desiraju (7) postulated thatshowing of alpha frequency is dueto decreased energy metabolism of brain.In our study alpha activity was significantlyhigher in meditators. These results

Indian J Physiol Pharmacol 2000; 44(2) A Study of Electroencephalogram in Meditators 177

TABLE VI: Showing comparison of beta percentage in frontalarea in control and tranced ental meditators.

Study group ControlPsoalue

Mean ± S.D. Mea.n ± S.D.

Before R: 41.42 24.06 66.89 13.52 < 0.01L: 40.93 22.12 64.45 18.16 < 0.01

During R: 31.04 19.46 71.31 28.57 < 0.001L: 30.63 19.75 71.55 29.00 < 0.001

are similar to those reported by Banquetet al (5).

EEG pattern which characterisedsleep (High voltage slow wave pattern12-14 cycles/sec.), sleep spindles andlow voltage mixed frequency with orwithout rapid eye movements were notseen during meditation. After 6 to 7 hoursof sleep high voltage slow wave activitywas seen. Whereas only 5 to 10 minutesof meditation, alpha waves activitypredominated in the electroencephalo-gram (10).

Alpha activity is produced in meditatorsby activation of diaphragmatic breathingthan thoracic breathing. The breath becomesthe object of awareness in most methods ofmeditation (8).

Wallace et al (3) found that thosepersons who practiced meditationcan continue to exhibit alpha and thetawaves after meditation period hadended. Our group also showed persistenceof alpha waves after meditation(Table III)

The cortex of brain consists of two halvesthe left and right hemisphere. Speech,logical thinking, analysis and sense of timeare thought to function in left hemisphere,while ability to recognize faces andcomprehend maps and intuitive function isthought to function in right hemisphere.

Right hemisphere is also a centre for motorskills and spatial awareness (3).

Meditation leads to development of righthemisphere associated abilities (10). Thishas been further verified by severalresearchers and they found that EEG alphaand theta wave coherence is most markedin right hemisphere during meditation (9,13, 15).

Our study also revealed good coherencein both hemispheres which is in accordancewith above authors. A good coherencebetween two hemispheres represents thesynchronization of logical with intuitivefunctions of brain (8). A significant findingthat emerged from Banquet's researches (5)was that brain wave patterns tend tosynchronize during deep meditation to thisphenomena of marked uniformity offrequency and amplitude in electricalactivity from all areas of brain, Banquetgave the name of "Hypersynchrony".According to him this may have somethingto do with feeling of pure awareness orconsciousness (4, 5).

Meditator groups showed persistence ofalpha waves after eye opening in 28.9%cases. Our observations are in conformitywith Kras et al (11) who found thatmeditators experienced calm and alert stateof mind which is maintained even duringdynamic activity and there was increase in

178 Khare and Nigam

alpha percentage in meditators even wheneyes were open. In our study right and lefthemispheric alpha voltage ratio whichwas 0.844 before meditation became7.876 during meditation. Kiloh et al(12) found decrease in alpha activity onleft side during performance ofmental arithmetic. During act of meditation,there occur inter-hemispheric symmetryin alpha rhythm, which is found in ourcases too.

Indian J Physiol Pharmacol 2000; 44(2)

In conclusion, we found that meditationenhance greater self-confidence, senseof well-being, empathy, improvescognitive function as evidenced byincreased alpha wave activity andits synchronization. It also increasesmental concentration and reducessusceptibility to stress and strain thuspromotes complete health and well-being inan individual.

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