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Quantitative EEG analysis during hypnosis
Electroencephalography and Clinical Neurophysiology Elsevier Publishing Company, Amsterdam - Printed in The Netherlands
QUANTITATIVE
EEG ANALYSIS
DURING
361
HYPNOSIS
GEORGE A . ULETT, SEVKET AKPINAR AND TURAN M . ITIL Missouri Institute of Psychiatry, University of Missouri School of Medicine, 5400 Arsenal Street, St. Louis, Mo. 63139 (U.S.A.) (Accepted for publication: March 7, 1972)
Although there have been intensive investigations in the past involving hypnosis and the electroencephalogram (EEG), thus far there has been no agreement upon any significant EEG correlations for the hypnotic state. The absence of substantive positive findings in this regard may be due in part to methodological difficulties, including the highly variable subjective approach that typifies the usual induction procedure. Quantitative analysis of the EEG has been used for years but has not been applied systematically to studies of hypnosis. In the framework of our current investigations (Akpinar et al. 1971; Ulett et al. 1972a), we have sought to overcome these difficulties and have concentrated on ascertaining quantitative EEG correlates of the hypnotic state. To this end we have studied EEG findings during a standardized hypnotic induction and hypnotic trance procedure using a pre-recorded, video-taped hypnotic induction technique (Ulett et al. 1971, 1972b) for all hypnotic sessions, as well as using digital computer and electronic frequency analyzer methods for EEG quantification. MATERIAL AND METHOD
The 10 best (6 male and 4 female, age range 28-29 years) and 10 poorest (6 male and 4 female, age range 25-26 years) hypnotic subjects were selected from a group of 44 previously hypnotized normal volunteers. These subjects were hypnotized with a standard induction procedure using task motivational instructions described by Barber and Calverley (1963). The induction 1 Presented at Annual Meeting, American EEG Society, Minneapolis, Minn., September 1971.
procedure (trance induction) itself was prerecorded on a black-and-white video-tape and presented on a 23 in. commercial television set, placed 10 ft away at eye level, to the subject who was seated in a comfortable reclining chair. The depth of hypnotic trance reached by each subject was evaluated by two observers immediately after each hypnotic session (trance testing) using the Barber Suggestibility Scale (BBS) (1965) and a hypnotic questionnaire (selfrating scale) developed in our laboratory (Ulett 1970). The BSS objective test questions for quantifying the depth of hypnotic trance were also recorded for video-tape playback. Subjects' responses were evaluated by the research assistants who recorded the scores using the method described by Barber (1965). A 10 rain resting (eyes closed) EEG recording was taken before the hypnotic session, followed by a 10 min recording during trance induction and an 8 rain record during the trance-testing period. All recordings were made on a Grass Model 6 EEG machine. The right occipital to right ear lead was analyzed on-line using an electronic frequency analyzer (Ulett and Loeffel 1953) and, in addition, was recorded on analog tape (Ampex FR-1300) and analyzed later using digital computer period analysis programs (Shapiro and Fink 1966). In comparing EEGs, the baseline resting record was used as the mean zero value from which deviations were demonstrated during trance-induction and trance-testing periods. RESULTS
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significance (Analysis of Variance ~ N O V ) in any of the 19 EEG variables during the tranceinduction period. Analysis based on the t test did show the increase in average absolute amplitude to be significant (P < 0.05). During the trance-testing period the EEG changes showed a profile similar to that seen during the trance-induction period; however. more changes now reached a level of statistical (ANOV. t lest) significance (decrease of 0 3.5 and 3.5 7.5 c/see activities (P<0,01), increase of 7.5-13 and 13-20 c/see activities ( P < 0.05) and increase of average absolute amplitude (P.~ 0.01)). l h e sepaFatc c x a l u a l i o n ol the l : l ( ; c h a n g e s
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Fig. 1. EEG changes under hypnosis (based on digital computer period analysis}.
ol 3.5 L3 c scc (P--U.OI) alld increase of 7.5 13 c/see ( P < 0.01)activity in the primary wave and decrease of 16 20 c/see (P<0.05) and 20 26 c/see (P < 0.01) activities in the first derivative, as well as an increase of average absolute amplitude and decrease of amplitude variability (both P<0.05) (Fig. 21). The changes in the poorest hypnotic subjects were less apparent than ill the
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ing periods, the entire group exhibited EEG patterns with a predominance of alpha activity (Fig. 1). The high amount of activity above 50 c/see seen in the first derivative digital computer analysis data from this group is accounted for by the 10 most readily hypnotizable subjects of the group whose unfiltered EEGs, as we have previously reported (Akpinar et al. 1971), are characterized by the presence of such rapid activity. During the trance-induction period, as compared with the resting EEG, there was a decrease of 3.5-7.5 and 13-20 c/sec and an increase of 7.5-13c/sec activity in the primary wave (zero cross), whereas there was an increase of 40 c/see superimposed fast waves (first derivative) and average frequency (first derivative) as well as an increase of average absolute amplitude and decrease of amplitude variability. Statistical evaluation demonstrated that changes did not reach a level of statistical
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7.5-13 c/sec (P<0.01) and 13-20 c/sec activity ( P < 0.05) in the primary wave as well as more 10 16 c/sec ( P < 0.05) and less 20 26 c/sec ( P < 0.01) activity in the first derivative measurements (Fig. 2), During the trance-testing period, a comparison of the two groups showed very few differences, with only the reduced amplitude variability in the best hypnotic subjects reaching a level of significance (P < 0.05).
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good hypnotic subjects and were in almost an opposite direction. During the trance-testing period in the best hypnotic subjects, there was a statistically (t test) significant (P changed from 0.05 to 0.01) decrease in 0-3.5 and 3.5-7.5 c/sec activity and an increase in 7.5-13 and 13-20 c/sec activity in the primary wave, a decrease in 20-26 c/sec activity in the first derivative and an increase of average absolute amplitude (P < 0.05). In the poorest hypnotic subjects only the decrease of 0-3.5 and 3.5-7.5 c/sec activities and increase in amplitude variability reached a level of statistical significance (P ranged from 0.05 to 0.01). When the above data were examined, not separately but rather in terms of comparing the two groups by analysis of variance, it was found that during the trance-testing period, the best hypnotic subjects have significantly less 0.5-3.5 and 3.5-7.5 c/see activity and more
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364 power in the 3.5-7 c/sec frequency bands (P< 0.01) and a significant (P< 0.05) increase in the 22 c/sec band as compared with the resting recordings, were observed. When we analyzed the EEG power spectra of the i0 best and 10 poorest hypnotic subjects during trance induction, as well as during the trance-testing period, a decrease of slow waves and ~ncrease of alpha activity were observed in both groups (Fig. 4). However, during trance induction, the decrease of power in the slow frequencies reached a level of statistical significance in only the best hypnotic subjects. During the trance-testing period, the decrease of power in the slow frequencies reached a level of statistical significance in both groups of subjects. Although the best hypnotic subjects still showed the greatest amount of change, the differences between the EEG changes of the two groups were statistically significant only during the tranceinduction period (Fig. 4). DISCUSSION
Previous studies using visual evaluation of the EEG have yielded contradictory results regarding EEG alterations during the hypnotic trance. A majority of investigators have claimed that the EEG during hypnosis resembles that of the awake state (Loomis et al. 1936a; Sirna 1945; Spiegel et a/.1945; Dynes 1947; Heimann and Spoerri 1953; Chertok and Kramarz 1959; Diamant et al. 1960). On the other hand a few investigators observed sleep patterns during hypnosis (Barker and Burgwin 1949; Darrow et al. 1950; Gilyarovskiy et al. 1960; Zikmund 1964). Another group of investigators reported some spike-like waves in the beta and theta ranges (Israel and Rohmer 1958), whereas still others found an increase in EEG irregularities (Stojanow and Heidrich 1962; Jus and Jus 1963; Zanocci and Gori 1963). In our study two different types of quantitative analysis demonstrated obvious EEG alterations during hypnotic induction and trance. These changes were observed, in general, during both the tranceinduction and trance-testing periods and were characterized by a decrease of slow activity and an increase of alpha and relatively high frequency, fast activity. The aforementioned
G.A. ULETTet al. changes were relatively less apparent during the trance-induction period, particularly in poor hypnotic subjects. There were obvious EEG differences between the poor and good hypnotic subjects, specifically during the trance-induction period. The EEG patterns in the best hypnotic subjects began to change significantly during trance induction and were further potentiated during the trance-testing period. One of the striking features seen in the period analysis output is the occurrence of changes in the opposite direction during trance induction in the poorest as compared with the best hypnotic subjects. Yet in the analog power spectra, the changes are in the same direction. These findings can be interpreted in terms of what is happening to the EEG wave form. During trance induction in the "poorest" subjects, the number of waves at 0-7.5 sec increases and yet the total "power" falls. This suggests an increase in the number of waves in bands which are, however, of much smaller amplitude. Furthermore, during trance induction in these subjects, the number of baseline crossings at 7.5-11.0 falls, whereas the total "power" increases, which indicates a reduced number of waves of relatively large amplitude. Perhaps the most significant EEG difference between subjects who exhibited deep hypnotic trance and those who did not was the behavior of the alpha frequencies. Although both poor and good hypnotic subjects showed a decrease of slow and an increase of fast activity during the trance-testing period, deep hypnosis was associated with a significant increase of alpha abundance. The increase of alpha activity during the hypnotic trance has been reported previously by a number of investigators (Marinesco et al. 1937; Franek and Thren 1949; Vesely 1950). However, these alpha activity findings have generally been minimized, and no particular emphasis has been placed upon them. An increased amount of alpha activity in the EEG has also been observed during different behavioral intervention techniques such as Yoga (Anand et al. 1961), Zen meditation (Okuma et al. 1957) and autogenic training (Israel and Rohmer 1958 ; Schultz and Luthe 1961; Jus and Jus 1963) as well as during "step-wise hypnotic exercises" developed by Kretschmer (Franek and Thren Electroenceph. clin. Neurophysiol., 1972, 33:361 -368
QUANTITATIVELEG ANALYSISDURINGHYPNOSIS 1949). Bagchi and Wenger (1957) demonstrated the occurrence of continuous alpha waves, with well modulated amplitudes and no sign of any rapid component, in the EEGs of meditating Yogis in a state of concentration. They concluded that Yogi meditation is a state of deep autonomic relaxation with wakening cerebral activity of a given type. Rhythmic theta bursts were seen in addition to alpha activity in some subjects during autogenic training and Zen meditation (Geissmann et al, 1963; Luthe et al. 1963; Kasamatsu and Hirai 1969). However, this theta activity might be related to a longer training period (Kretschmer 1969). In recent years the significance of alpha activity with regard to behavior modification has been noted frequently. Kamiya (1969) reported that individuals who have practiced meditation are much better at learning operant control of alpha activity. In their years of meditation, Zen monks and Yogis have actually learned to produce a high alpha state (Tart 1969). In addition, studies with psychotropic drugs have demonstrated that synchronized rhythmical alpha activity is a characteristic of all the major tranquilizers (Itil 1964). It is perhaps even more significant that an improvement in the psychopathology of acute schizophrenics can also be associated with increased alpha activity (Itil 1968). Various EEG and evoked potential studies have demonstrated that there is inhibition of the alpha blocking effects of different types of sensory stimulation during the hypnotic trance (Hern/mdez-Pe6n and Donoso 1957; Diamant et al. 1960; Jouvet 1961; Aksoy and Mentzos 1963; Barolin 1968; Wilson 1968). Subjects experiencing hypnotically suggested blindness or deafness are able to open their eyes or be exposed to a stimulus without any resultant alpha blocking, as would be the case if they were truly blind (Loomis et al. 1936a, b; Schwarz et al. 1955; Yeager and Larson 1958). Although the results are still the subject of controversy, evoked responses have actually been found to be more stable during hypnosis (Titeca 1938; Lundholm and L6wenbach 1942; Barker and Burgwin 1949; Gorton 1949; Halliday and Mason 1964; Beck and Barolin 1965; Serafetinides 1968). A decrease in the alpha blocking effect has
365 also been observed during chronic administration of major tranquilizers (Bente and Itil 1954). It has been hypothesized that alpha blocking is due to a phasic barrage of ascending reticular impulses which probably disrupt the slow cortical rhythms by desynchronizing the thalarnic pacemaker (Moruzzi 1964). One could speculate that during the complete relaxation induced by hypnosis, as well as autohypnosis, Yoga and Zen meditation, autogenic training and alpha training, the sensory impulses that are usually integrated in the reticular activating system of the brain stem and thalamus have been attenuated functionally, so that this system cannot exercise an arousal effect on the cortex. This internal inhibition under hypnosis enhances selective att~ftion to signal input from the environment, with selective inattention to irrelevant stimuli (Kroger 1970). Kroger suggested that with proper suggestions under hypnosis or with sufficient practice in autohypnosis, when complete relaxation and increased concentration are reached, the state of motivation for adverse stimuli (such as over-eating or smoking) can also be inhibited. Inhibition of the excitatory impulses at the cortex can be associated with a decrease of vigilance, a state which is close to sleep stage A and is characterized by an increase of alpha activity ~nd synchronization (Loomis et al. 1937). A further decrease in vigilance results in an EEG pattern which resembles light sleep (drowsiness stage, stage 1 or B). Our study demonstrated that the EEG of the hypnotic state is a well defined entity characterized by continuous large amplitude alpha waves, as well as less slow and more fast activity. These EEG patterns are more similar to stage A sleep than to drowsiness, light sleep or the previously described rapid eye movement state (Itil 1970). Hypnosis, autohypnosis, Yoga, Zen meditation and autogenic and alpha training are all phenomena which exhibit large amplitude alpha EEGs as a common characteristic. SUMMARY Although some investigators have previously reported light or deep sleep EEG patterns during hypnosis, most of them have not demonstrated Electroenceph. clin. Neurophysiol., 1972,33:361 368
366 any significant EEG differences between the hypnotic and the awake states. By quantitative clectroencephalographic (EEG) methods, using digital computer period analysis and analog frequency analyzer techniques, our study demonstrated statistically (ANOV and t test) significant EEG changes during both hypnotic induction and hypnotic trance. These changes were far from drowsiness or sleep EEG patterns. During hypnotic induction, there was a significant decrease of slow and increase of alpha and beta waves accompanied by an increase in amplitude and decrease of amplitude variability, in the best hypnotic subjects. Both the best and the poorest hypnotic subjects exhibited similar changes during the hypnotic trance period, although the best hypnotic subjects showed greater EEG changes, in particular, significantly more alpha activity, than the poorest ones. Augmented alpha activity can also be seen during Yoga and Zen meditation as well as autogenic and alpha training, which seems to indicate that hypnosis has something in common with these states. RESUME ANALYSE EEG QUANTITATIVE AU COURS DE L'HYPNOSE
Bien que certains chercheurs aient pr6c6demment rapport6 des patterns de sommeil 16ger ou profond au cours de l'hypnose, la plupart d'entre eux n'ont pas fait la preuve de diff6rences EEG significatives entre les stades d'hypnose et les stades de veille. Par des m6thodes d'61ectroenc6phalographie quantitative, utilisant des techniques d'analyse digitale de p6riode et d'analyse analogique de fr6quence, notre 6tude a d6montr6 des modifications EEG statistiquement significatives (ANOV et Test t) au cours de l'induction de l'hypnose et de la transe hypnotique. Ces modifications sont loin d'&re similaires aux patterns EEG d'endormissement ou de sommeil. Au cours de l'induction hypnotique, il y a une diminution significative des ondes lentes et une augmentation des ondes alpha et b&a accompagnde par une augmentation d'amplitude et une diminution de la variabilit6 d'amplitude chez les sujets les plus sensibles ~ l'hypnose. Les sujets les moins et les plus sensibles/~ l'hypnose
G.A. UI£TT et al. ont montr6 des modifications similaires au cours de la p6riode de transe hypnotique bien que les premiers aient montr6 des modifications EEG plus grandes, et en particulier une activit6 alpha signifiquement plus importante que les seconds. L'activit6 alpha augmentde peut 6galement s'observer au cours du Yoga et de la mdditatio n Yen, de mame qu'au cours du training autog6ne et du training alpha, ce qui semble indiquer que l'hypnose air quelque chose en commun avec ces 6tats. We wish to acknowledge the assistance of Mrs. S. Davis. R. N.; Michael Heusler and Margaret Baeyen, EEG technicians: John Marasa, scientific programmer/analyst, and Barry Bergey, editorial assistant. REFERENCES
AKPINAR, S., ULETT,G. A. and ITIL, T. M. Hypnotizability predicted by digital computer analyzed EEG pattern. Biol. Psyehiat., 1971, 3: 387. AKSOY, F. und MENTZOS, S. Hypnose und EEG. Z. ,qcs'. Neurol. Psychiat., 1963, 176: 204. ANAND, B. K., CHH1NA, G. S. and SINk;H, B. Some aspects of electroencephalographic studies in Yogis. Electroenceph, clin. Neurophysiol., 1961, 13: 452456. BAGCHI, B. and WENGER, M. Electrophysiological correlates of some Yogi exercises. Electroenceph. clin. Neurophysiol., 1957, 7:132 149. BARBER, T. X. Measuring "hypnotic-like" suggestibility with and without "hypnotic induction": psychometric properties, norms, and variables influencing response to the Barber Suggestibility Scale (BSS). Psvchol. Rep., 1965, 16: 809-844. BARBER, T. X. and CAI,VERLEY, D. S. Toward a theory of hypnotic behavior: effects on suggestibility of task motivating instructions and attitudes toward hypnosis. J. abnorm, soc. PsychoL, 1963, 64: I I 1 128. BARKER, W. and BURGWIN, S. Brain wave patterns during hypnosis, hypnotic sleep and normal sleep. Arch. Neurol. Ps'ychiat. (Chic.), 1949, 62: 412M20. BAROLIN, G. S. Hirnelektrische Korrelate in hypnoiden ZustS.nden. Fortschr. Neurol. Psychiat., 1968, 36: 227246. BECK,E. C. and BAROLIN,G. S. Effect of hypnotic suggestions on evoked potentials. J. herr,, ment. Dis., 1965, 140: 154-161. BENTE, D. und ITIL, T. M. Zur Wirkung des phenothiazinkoerpers Megaphen auf das menschliche Hirnstrombild. Arzneimittel-Forsch., 1954, 4: 418M23. CHERTOK, L. and KRAMARZ,P. Hypnosis, sleep and electroencephalography. J. nerv. ment. Dis., 1959, 128:227-238, DARROW, C. W., HENRY, C. E., GILl., M., BRENMAN, M, and CONVERSE, M. Frontal-motor parallelism and motor-occipital in-phase activity in hypnosis~ drowsiness and sleep. Eleetroenceph. olin. Neurophysiol.. 1950, 2: 355. Electroenceph. clin. Neurophysiol., 1972, 33:361 368
367
QUANFITATIVE EEG ANALYSIS DURING HYPNOSIS DIA\IANr, J., DUFEK, M.. HOSKOVEC, J., KRIg'roF, M., PEK~REK. V., ROTH, B. and VELEK, M. An electroencephalographic study of the waking state and hypnosis with particular references to subclinical manifestations of sleep activity. Int. J. clin. exp. Hypnos., 1960, 8: 199 212. DYNES. J. B. Objective method for distinguishing sleep from the hypnotic trance. Arch. Neurol. Psychiat. (Chic.), 1947, 57: 84-93. FRANEK, B. und THREN, R. Hirnelektrische Befunde bei gesluftenaktiven Hypnosefibungen. Arch. Psychiat. Nervenkr., 1949, 181: 360-369. GEISSMANN, P., Jus, A. and LUTHE, W. Neurophysiologic and psychophysiologic aspects of the autogenic state. in Proc. 3rd Worht Congr. Psychiat., Vol. lli. University of Toronto Press, Toronto, 1963: 464468. GILYAROVSKIY, V. A., LIVENTSEV, I. M,, SEGAL, Y. Y. and KIRII,I OVA,Z. A. [Electric sleep ( A clinical-physiological hwestigation) .] (English translation). U.S. Joint Publications Research Service, Washington, D.C., 1960, 233 p. GORrON, B. E. The physiology of hypnosis. A review of the literature. Psychiat. Quart., 1949, 23: 317-343, 457 485. HA~ ~JD¢Y, A. M. and MASON, A. A. The effect of hypnotic anaesthesia on cortical responses. J. Neurol. Neurosurg. Psychiat., 1964, 27:300-312. ]IEIMANN, H. und SPOERRI, T. Elektroencephalographische Untersuchungen an Hypnotisierten. Mschr. Psychiat. Neurol., 1953, 125: 261-271. HERN~NDEZ-PE6N, R. and DONOSO, M. Subcortical photically evoked electrical activity in the human waking brain. In Proc. ist lnternat. Cong. Neurol. Sci., Vol. 111. Excerpta Medica, Amsterdam, 1957: 385-396. ISRAtI,, L. et ROHMER, F. Variations dlectroencdphalographiq ues au cours de la relaxation autog6ne et hypnotique. In P. ABOULKERet al. (Eds.), La relaxation. Expansion Scientif. Franqaise, Paris, 1958:88 98. ITH, T. M. Eh, ktroencephalographische Studien bei Psychosen und Psychotropen Medikamenten. Ahmet Salt Matbaasi, 1964, 128 p. ITH., T. M. Electroencephalography and pharmacopsychiatry. In F. A. FREYHAN et al. (Eds.), Clinical psychopharmacology, modern probh, ms q/'pharmacopsychiatJ T. S. Karger, Basel/New York, 1968:163 194. lTn,, T. M. Digital computer analysis of the electroencephalogram during rapid eye movement sleep state in man. J. nerv. ment. Dis., 1970, 150: 20l. JOUVET, M. Photically and somaesthetically subcortical electric activity in the human brain during attention. In Proc. 5th lnternat. Congr. Electroenceph. Clin. NeurophysioL lnternatianal Congress Series No. 37. Excerpta Medica, Amsterdam, 1961: 80-81. Jus, A. and Jus, K. Polygraphic research in autogenic training. In Proc. 3rd World Congr. Psychiat, Vol. 111. University of Toronto Press, Toronto, 1963: 473~82. KAM1YA,J. Operant control of the EEG alpha rhythm and some of its reported effects on consciousness, in C. TAR1 (Ed.), Altered states O/consciousness. John Wiley, N.Y., 1969:507 517. KASAMA~Sb, A. and HIRM, T. An electroencephalographic study on the Zen meditation (zazen). In C. TART (Ed.), .4 Itered states 0[ consciousness. John Wiley, N.Y., 1969 :
489--50l. KRETSCHMER, W. Meditation techniques in psychotherapy. In C. TARa" (Ed.), Altered states ()/' consciousness. John Wiley, N.Y., 1969:219 228. KROGER,W. S. Systems approach for understanding obesity : management by behavioral modification through hypnosis. PsTchiat. Opinion, 1970, 7:7 19. LOOMIS, A. L., HARVEY, E. N. and HOBART. G. Brain potentials during hypnosis. Science, 1936a, 83: 239-241. LOOMIS, A. L., HARVEY, E. N. and HOBART, G. Electrical potentials of the human brain. J. exp. Psyehol., 1936b, 19:249 279. LOOMIS, A. L., HARVEY, E. N. and HOBART, G. A. Cerebral states during sleep as studied by human brain potentials. J. exp. Psychol., 1937, 21:127 144. LUNDHOLM, H. and L(JWENBA('H, H. Hypnosis and the alpha activity of the electroencephalogram. Character andperson, 1942, 11 : 145 149. LUTHE, W., Jus, A. and GEISSMANN,P. Autogenic state and autogenic shift : psychophysiologic and neurophysiologic aspects. Acta psychother. (Basel), 1963, I1 : I 13. MARINKgCO,G., SAGER,D. et KREINDLER,A. Etudes 61ectroencdphalographiques. Le sommeil naturel et le sommeil hypnotic. Bull. Acad. Mdd. (Paris), 1937, I 17:272 276. MORUZZl, G. Reticular influences on the EEG. Electroenceph, clin. Neurophysiol., 1964, 16: 2-17. OKUMA, T., KOGA, E., 1KEDA, K. and SUGIYAMA, H. The EEG of Zen and Yoga practitioners. Electroenceph. olin. Neurophysiol., 1957, Suppl. 9: 51-52. SCHULTZ, J. and LUTHE, W. Autogenic training. In Proc. 3rd World Congr. Psychiat., Vol. I. University of Toronto Press, Toronto, 1961:191 200. SCHWARZ, B, E., BICKFORD, R. G. and RASMUSSEN,W. C. Hypnotic phenomena including hypnotically activated seizures : studies with the electroencephalogram. J. nero. ment. Dis'., 1955, 122:564 574. SERAFETINIDES, E. A. Electrophysiological responses to sensory stimulation under hypnosis. Amer. J. Psrchiat., 1968, 125:150-151. SHAPIRO, D. M. and FINK, M. Quantitative ana(vsis q/' the eleetroencephalogram by digital computer methods'. Psychiatric Research Foundation of Missouri, St. Louis, Mo,. 1966. 118 p.
S1RNA, A. J. An electroencephalographic study of the hypnotic dream. J. Psychol., 1945, 20:109 113. SPIEGEL, H., SHOR, J. and FISHMAN,S. An hypnotic ablation technique for the study of personality development. Psychosom. Med., 1945, 7:273 278. STOJANOW, W. und HHDRICH, R. Das EEG wS_hrend des autogenen Trainings. Psychiat. Neurol. reed. Psyehol. (Lpz.), 1962, 14:13 18. TART, C. (Ed.). Altered states o f consciousness. John Wiley, New York, 1969, 575 p. TIr~('A, J. Etude 61ectroenc6phalographique de deux cas d'anesth6sie hystdrique. J. belye Neurol. P~sTchiat., 1938, 38 : 442-478. ULETT,G. A. lqvpnosisquestionnairvlbrse(l)'atiml. Psychiatric Research Foundation of Missouri. SI. Louis, Mo.. 1970, 4p. ULETT, G. A. and LOEFFEI,,R. G. A nc\~ resonator-mtegrato~ unit lbr the automatic brain wave analyzer, lih, cn'o Eleetroeneeph. e/in. Neurophvsiol., 1972, 33:361 368
368
G . A . ULETT et al.
enceph, clin. Neurophysiol., 1953, 5:113-115. LILETT, G. A., AKPINAR, S. and ITIL, T. M. Investigations of hypnosis utilizing induction by video tape. Psychosomatics, 1971, 12: 250. ULETT, G. A., AKPINAR, S. and ITIL, T. M. Hypnosis: physiological, pharmacological reality. Amer. J. Psychiat., 1972a, 128: 7. ULETT, G. A., AKPINAR, S. and ITIL, T. M. Hypnosis by video tape. Int. J. clin. exp. Hypnos., 1972b, 20: 46. VESELY, L. [EEG recording of the hypnotic state.] (in Czech). Neurol. psychiat. ~s., 1950, 13: 210-219. WILSON, N. J. Neurophysiologic alterations with hypnosis.
Dis. nerv. Syst., 1968, 29: 618-620. YEAGER, C. L. and LARSON, A. A study of alpha desynchronization in the electroencephalogram, utilizing hypnotic suggestion. Electroenceph. clin. Neurophysiol., 1958, I0: 193-194. ZANOCCI, G. and GORI, E. Observation on the psychophysiological variations related to hypnotic behaviour. Eleetroenceph. olin. Neurophysiol., 1963, 15: 920-921. ZmMUNO, V. Some physiological characteristics of natural and hypnotic sleep in man. Physiol. bohemoslot,., 1964, 13: 196-201.
Reference: ULETT, G. A., AKPINAR,S. and ITIL, T. M. Quantitative EEG analysis during hypnosis. Electroenceph. clin. Neurophysiol., 1972, 33: 361-368.
QUANTITATIVE
EEG ANALYSIS
DURING
361
HYPNOSIS
GEORGE A . ULETT, SEVKET AKPINAR AND TURAN M . ITIL Missouri Institute of Psychiatry, University of Missouri School of Medicine, 5400 Arsenal Street, St. Louis, Mo. 63139 (U.S.A.) (Accepted for publication: March 7, 1972)
Although there have been intensive investigations in the past involving hypnosis and the electroencephalogram (EEG), thus far there has been no agreement upon any significant EEG correlations for the hypnotic state. The absence of substantive positive findings in this regard may be due in part to methodological difficulties, including the highly variable subjective approach that typifies the usual induction procedure. Quantitative analysis of the EEG has been used for years but has not been applied systematically to studies of hypnosis. In the framework of our current investigations (Akpinar et al. 1971; Ulett et al. 1972a), we have sought to overcome these difficulties and have concentrated on ascertaining quantitative EEG correlates of the hypnotic state. To this end we have studied EEG findings during a standardized hypnotic induction and hypnotic trance procedure using a pre-recorded, video-taped hypnotic induction technique (Ulett et al. 1971, 1972b) for all hypnotic sessions, as well as using digital computer and electronic frequency analyzer methods for EEG quantification. MATERIAL AND METHOD
The 10 best (6 male and 4 female, age range 28-29 years) and 10 poorest (6 male and 4 female, age range 25-26 years) hypnotic subjects were selected from a group of 44 previously hypnotized normal volunteers. These subjects were hypnotized with a standard induction procedure using task motivational instructions described by Barber and Calverley (1963). The induction 1 Presented at Annual Meeting, American EEG Society, Minneapolis, Minn., September 1971.
procedure (trance induction) itself was prerecorded on a black-and-white video-tape and presented on a 23 in. commercial television set, placed 10 ft away at eye level, to the subject who was seated in a comfortable reclining chair. The depth of hypnotic trance reached by each subject was evaluated by two observers immediately after each hypnotic session (trance testing) using the Barber Suggestibility Scale (BBS) (1965) and a hypnotic questionnaire (selfrating scale) developed in our laboratory (Ulett 1970). The BSS objective test questions for quantifying the depth of hypnotic trance were also recorded for video-tape playback. Subjects' responses were evaluated by the research assistants who recorded the scores using the method described by Barber (1965). A 10 rain resting (eyes closed) EEG recording was taken before the hypnotic session, followed by a 10 min recording during trance induction and an 8 rain record during the trance-testing period. All recordings were made on a Grass Model 6 EEG machine. The right occipital to right ear lead was analyzed on-line using an electronic frequency analyzer (Ulett and Loeffel 1953) and, in addition, was recorded on analog tape (Ampex FR-1300) and analyzed later using digital computer period analysis programs (Shapiro and Fink 1966). In comparing EEGs, the baseline resting record was used as the mean zero value from which deviations were demonstrated during trance-induction and trance-testing periods. RESULTS
Digital computer period analysis Before the trance-induction and trance-testElectroenceph. clin. Neurophysiol., ! 972, 33 : 361-368
362
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significance (Analysis of Variance ~ N O V ) in any of the 19 EEG variables during the tranceinduction period. Analysis based on the t test did show the increase in average absolute amplitude to be significant (P < 0.05). During the trance-testing period the EEG changes showed a profile similar to that seen during the trance-induction period; however. more changes now reached a level of statistical (ANOV. t lest) significance (decrease of 0 3.5 and 3.5 7.5 c/see activities (P<0,01), increase of 7.5-13 and 13-20 c/see activities ( P < 0.05) and increase of average absolute amplitude (P.~ 0.01)). l h e sepaFatc c x a l u a l i o n ol the l : l ( ; c h a n g e s
i n d u c t i o n period, the best h y p n o t i c subiects shox~,cd ~1 ShlliMicilll', (1 Icsl) ,tgnilic:ml decrease
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ol 3.5 L3 c scc (P--U.OI) alld increase of 7.5 13 c/see ( P < 0.01)activity in the primary wave and decrease of 16 20 c/see (P<0.05) and 20 26 c/see (P < 0.01) activities in the first derivative, as well as an increase of average absolute amplitude and decrease of amplitude variability (both P<0.05) (Fig. 21). The changes in the poorest hypnotic subjects were less apparent than ill the
( 5-40}
K-FILTER
ing periods, the entire group exhibited EEG patterns with a predominance of alpha activity (Fig. 1). The high amount of activity above 50 c/see seen in the first derivative digital computer analysis data from this group is accounted for by the 10 most readily hypnotizable subjects of the group whose unfiltered EEGs, as we have previously reported (Akpinar et al. 1971), are characterized by the presence of such rapid activity. During the trance-induction period, as compared with the resting EEG, there was a decrease of 3.5-7.5 and 13-20 c/sec and an increase of 7.5-13c/sec activity in the primary wave (zero cross), whereas there was an increase of 40 c/see superimposed fast waves (first derivative) and average frequency (first derivative) as well as an increase of average absolute amplitude and decrease of amplitude variability. Statistical evaluation demonstrated that changes did not reach a level of statistical
~ d O B E S T HYPNOTIC SUBJECTS mI,I,IOPOOREST HYPNOTIC SUBJECTS •
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Fig. 2, EEG changes under hypnosis (based on computer period analysis }. Electroenceph. c/in. ,~,'cm'ophvsm/., 1972, 33 : 361- 368
363
QUANrlTAT1VE EEG ANALYSIS DURING HYPNOSIS (N20) O IOmin RESTING-TRANCE
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.125, +100*75.50. *25-
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Frequency analyzer Analog frequency analyzer data showed that the total group exhibited predominant power in the 9 c/sec frequency band before the hypnotic session. During the trance-induction period, there was a significant increase of power in the 9 c/see frequency band (t test, P < 0.05) (Fig. 3), whereas during trance testing, a decrease of
"6 g
-50. If .175-
IOrnin
RESTING-TRANCE
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7.5-13 c/sec (P<0.01) and 13-20 c/sec activity ( P < 0.05) in the primary wave as well as more 10 16 c/sec ( P < 0.05) and less 20 26 c/sec ( P < 0.01) activity in the first derivative measurements (Fig. 2), During the trance-testing period, a comparison of the two groups showed very few differences, with only the reduced amplitude variability in the best hypnotic subjects reaching a level of significance (P < 0.05).
TESTING
÷100÷75 *50 *25 O -25
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good hypnotic subjects and were in almost an opposite direction. During the trance-testing period in the best hypnotic subjects, there was a statistically (t test) significant (P changed from 0.05 to 0.01) decrease in 0-3.5 and 3.5-7.5 c/sec activity and an increase in 7.5-13 and 13-20 c/sec activity in the primary wave, a decrease in 20-26 c/sec activity in the first derivative and an increase of average absolute amplitude (P < 0.05). In the poorest hypnotic subjects only the decrease of 0-3.5 and 3.5-7.5 c/sec activities and increase in amplitude variability reached a level of statistical significance (P ranged from 0.05 to 0.01). When the above data were examined, not separately but rather in terms of comparing the two groups by analysis of variance, it was found that during the trance-testing period, the best hypnotic subjects have significantly less 0.5-3.5 and 3.5-7.5 c/see activity and more
%
-z 150
I
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Fig. 4. EEG changes under hypnosis based on analog power spectra. Electroenceph. clin. Neurophysiol., 1972, 33 : 361-368
364 power in the 3.5-7 c/sec frequency bands (P< 0.01) and a significant (P< 0.05) increase in the 22 c/sec band as compared with the resting recordings, were observed. When we analyzed the EEG power spectra of the i0 best and 10 poorest hypnotic subjects during trance induction, as well as during the trance-testing period, a decrease of slow waves and ~ncrease of alpha activity were observed in both groups (Fig. 4). However, during trance induction, the decrease of power in the slow frequencies reached a level of statistical significance in only the best hypnotic subjects. During the trance-testing period, the decrease of power in the slow frequencies reached a level of statistical significance in both groups of subjects. Although the best hypnotic subjects still showed the greatest amount of change, the differences between the EEG changes of the two groups were statistically significant only during the tranceinduction period (Fig. 4). DISCUSSION
Previous studies using visual evaluation of the EEG have yielded contradictory results regarding EEG alterations during the hypnotic trance. A majority of investigators have claimed that the EEG during hypnosis resembles that of the awake state (Loomis et al. 1936a; Sirna 1945; Spiegel et a/.1945; Dynes 1947; Heimann and Spoerri 1953; Chertok and Kramarz 1959; Diamant et al. 1960). On the other hand a few investigators observed sleep patterns during hypnosis (Barker and Burgwin 1949; Darrow et al. 1950; Gilyarovskiy et al. 1960; Zikmund 1964). Another group of investigators reported some spike-like waves in the beta and theta ranges (Israel and Rohmer 1958), whereas still others found an increase in EEG irregularities (Stojanow and Heidrich 1962; Jus and Jus 1963; Zanocci and Gori 1963). In our study two different types of quantitative analysis demonstrated obvious EEG alterations during hypnotic induction and trance. These changes were observed, in general, during both the tranceinduction and trance-testing periods and were characterized by a decrease of slow activity and an increase of alpha and relatively high frequency, fast activity. The aforementioned
G.A. ULETTet al. changes were relatively less apparent during the trance-induction period, particularly in poor hypnotic subjects. There were obvious EEG differences between the poor and good hypnotic subjects, specifically during the trance-induction period. The EEG patterns in the best hypnotic subjects began to change significantly during trance induction and were further potentiated during the trance-testing period. One of the striking features seen in the period analysis output is the occurrence of changes in the opposite direction during trance induction in the poorest as compared with the best hypnotic subjects. Yet in the analog power spectra, the changes are in the same direction. These findings can be interpreted in terms of what is happening to the EEG wave form. During trance induction in the "poorest" subjects, the number of waves at 0-7.5 sec increases and yet the total "power" falls. This suggests an increase in the number of waves in bands which are, however, of much smaller amplitude. Furthermore, during trance induction in these subjects, the number of baseline crossings at 7.5-11.0 falls, whereas the total "power" increases, which indicates a reduced number of waves of relatively large amplitude. Perhaps the most significant EEG difference between subjects who exhibited deep hypnotic trance and those who did not was the behavior of the alpha frequencies. Although both poor and good hypnotic subjects showed a decrease of slow and an increase of fast activity during the trance-testing period, deep hypnosis was associated with a significant increase of alpha abundance. The increase of alpha activity during the hypnotic trance has been reported previously by a number of investigators (Marinesco et al. 1937; Franek and Thren 1949; Vesely 1950). However, these alpha activity findings have generally been minimized, and no particular emphasis has been placed upon them. An increased amount of alpha activity in the EEG has also been observed during different behavioral intervention techniques such as Yoga (Anand et al. 1961), Zen meditation (Okuma et al. 1957) and autogenic training (Israel and Rohmer 1958 ; Schultz and Luthe 1961; Jus and Jus 1963) as well as during "step-wise hypnotic exercises" developed by Kretschmer (Franek and Thren Electroenceph. clin. Neurophysiol., 1972, 33:361 -368
QUANTITATIVELEG ANALYSISDURINGHYPNOSIS 1949). Bagchi and Wenger (1957) demonstrated the occurrence of continuous alpha waves, with well modulated amplitudes and no sign of any rapid component, in the EEGs of meditating Yogis in a state of concentration. They concluded that Yogi meditation is a state of deep autonomic relaxation with wakening cerebral activity of a given type. Rhythmic theta bursts were seen in addition to alpha activity in some subjects during autogenic training and Zen meditation (Geissmann et al, 1963; Luthe et al. 1963; Kasamatsu and Hirai 1969). However, this theta activity might be related to a longer training period (Kretschmer 1969). In recent years the significance of alpha activity with regard to behavior modification has been noted frequently. Kamiya (1969) reported that individuals who have practiced meditation are much better at learning operant control of alpha activity. In their years of meditation, Zen monks and Yogis have actually learned to produce a high alpha state (Tart 1969). In addition, studies with psychotropic drugs have demonstrated that synchronized rhythmical alpha activity is a characteristic of all the major tranquilizers (Itil 1964). It is perhaps even more significant that an improvement in the psychopathology of acute schizophrenics can also be associated with increased alpha activity (Itil 1968). Various EEG and evoked potential studies have demonstrated that there is inhibition of the alpha blocking effects of different types of sensory stimulation during the hypnotic trance (Hern/mdez-Pe6n and Donoso 1957; Diamant et al. 1960; Jouvet 1961; Aksoy and Mentzos 1963; Barolin 1968; Wilson 1968). Subjects experiencing hypnotically suggested blindness or deafness are able to open their eyes or be exposed to a stimulus without any resultant alpha blocking, as would be the case if they were truly blind (Loomis et al. 1936a, b; Schwarz et al. 1955; Yeager and Larson 1958). Although the results are still the subject of controversy, evoked responses have actually been found to be more stable during hypnosis (Titeca 1938; Lundholm and L6wenbach 1942; Barker and Burgwin 1949; Gorton 1949; Halliday and Mason 1964; Beck and Barolin 1965; Serafetinides 1968). A decrease in the alpha blocking effect has
365 also been observed during chronic administration of major tranquilizers (Bente and Itil 1954). It has been hypothesized that alpha blocking is due to a phasic barrage of ascending reticular impulses which probably disrupt the slow cortical rhythms by desynchronizing the thalarnic pacemaker (Moruzzi 1964). One could speculate that during the complete relaxation induced by hypnosis, as well as autohypnosis, Yoga and Zen meditation, autogenic training and alpha training, the sensory impulses that are usually integrated in the reticular activating system of the brain stem and thalamus have been attenuated functionally, so that this system cannot exercise an arousal effect on the cortex. This internal inhibition under hypnosis enhances selective att~ftion to signal input from the environment, with selective inattention to irrelevant stimuli (Kroger 1970). Kroger suggested that with proper suggestions under hypnosis or with sufficient practice in autohypnosis, when complete relaxation and increased concentration are reached, the state of motivation for adverse stimuli (such as over-eating or smoking) can also be inhibited. Inhibition of the excitatory impulses at the cortex can be associated with a decrease of vigilance, a state which is close to sleep stage A and is characterized by an increase of alpha activity ~nd synchronization (Loomis et al. 1937). A further decrease in vigilance results in an EEG pattern which resembles light sleep (drowsiness stage, stage 1 or B). Our study demonstrated that the EEG of the hypnotic state is a well defined entity characterized by continuous large amplitude alpha waves, as well as less slow and more fast activity. These EEG patterns are more similar to stage A sleep than to drowsiness, light sleep or the previously described rapid eye movement state (Itil 1970). Hypnosis, autohypnosis, Yoga, Zen meditation and autogenic and alpha training are all phenomena which exhibit large amplitude alpha EEGs as a common characteristic. SUMMARY Although some investigators have previously reported light or deep sleep EEG patterns during hypnosis, most of them have not demonstrated Electroenceph. clin. Neurophysiol., 1972,33:361 368
366 any significant EEG differences between the hypnotic and the awake states. By quantitative clectroencephalographic (EEG) methods, using digital computer period analysis and analog frequency analyzer techniques, our study demonstrated statistically (ANOV and t test) significant EEG changes during both hypnotic induction and hypnotic trance. These changes were far from drowsiness or sleep EEG patterns. During hypnotic induction, there was a significant decrease of slow and increase of alpha and beta waves accompanied by an increase in amplitude and decrease of amplitude variability, in the best hypnotic subjects. Both the best and the poorest hypnotic subjects exhibited similar changes during the hypnotic trance period, although the best hypnotic subjects showed greater EEG changes, in particular, significantly more alpha activity, than the poorest ones. Augmented alpha activity can also be seen during Yoga and Zen meditation as well as autogenic and alpha training, which seems to indicate that hypnosis has something in common with these states. RESUME ANALYSE EEG QUANTITATIVE AU COURS DE L'HYPNOSE
Bien que certains chercheurs aient pr6c6demment rapport6 des patterns de sommeil 16ger ou profond au cours de l'hypnose, la plupart d'entre eux n'ont pas fait la preuve de diff6rences EEG significatives entre les stades d'hypnose et les stades de veille. Par des m6thodes d'61ectroenc6phalographie quantitative, utilisant des techniques d'analyse digitale de p6riode et d'analyse analogique de fr6quence, notre 6tude a d6montr6 des modifications EEG statistiquement significatives (ANOV et Test t) au cours de l'induction de l'hypnose et de la transe hypnotique. Ces modifications sont loin d'&re similaires aux patterns EEG d'endormissement ou de sommeil. Au cours de l'induction hypnotique, il y a une diminution significative des ondes lentes et une augmentation des ondes alpha et b&a accompagnde par une augmentation d'amplitude et une diminution de la variabilit6 d'amplitude chez les sujets les plus sensibles ~ l'hypnose. Les sujets les moins et les plus sensibles/~ l'hypnose
G.A. UI£TT et al. ont montr6 des modifications similaires au cours de la p6riode de transe hypnotique bien que les premiers aient montr6 des modifications EEG plus grandes, et en particulier une activit6 alpha signifiquement plus importante que les seconds. L'activit6 alpha augmentde peut 6galement s'observer au cours du Yoga et de la mdditatio n Yen, de mame qu'au cours du training autog6ne et du training alpha, ce qui semble indiquer que l'hypnose air quelque chose en commun avec ces 6tats. We wish to acknowledge the assistance of Mrs. S. Davis. R. N.; Michael Heusler and Margaret Baeyen, EEG technicians: John Marasa, scientific programmer/analyst, and Barry Bergey, editorial assistant. REFERENCES
AKPINAR, S., ULETT,G. A. and ITIL, T. M. Hypnotizability predicted by digital computer analyzed EEG pattern. Biol. Psyehiat., 1971, 3: 387. AKSOY, F. und MENTZOS, S. Hypnose und EEG. Z. ,qcs'. Neurol. Psychiat., 1963, 176: 204. ANAND, B. K., CHH1NA, G. S. and SINk;H, B. Some aspects of electroencephalographic studies in Yogis. Electroenceph, clin. Neurophysiol., 1961, 13: 452456. BAGCHI, B. and WENGER, M. Electrophysiological correlates of some Yogi exercises. Electroenceph. clin. Neurophysiol., 1957, 7:132 149. BARBER, T. X. Measuring "hypnotic-like" suggestibility with and without "hypnotic induction": psychometric properties, norms, and variables influencing response to the Barber Suggestibility Scale (BSS). Psvchol. Rep., 1965, 16: 809-844. BARBER, T. X. and CAI,VERLEY, D. S. Toward a theory of hypnotic behavior: effects on suggestibility of task motivating instructions and attitudes toward hypnosis. J. abnorm, soc. PsychoL, 1963, 64: I I 1 128. BARKER, W. and BURGWIN, S. Brain wave patterns during hypnosis, hypnotic sleep and normal sleep. Arch. Neurol. Ps'ychiat. (Chic.), 1949, 62: 412M20. BAROLIN, G. S. Hirnelektrische Korrelate in hypnoiden ZustS.nden. Fortschr. Neurol. Psychiat., 1968, 36: 227246. BECK,E. C. and BAROLIN,G. S. Effect of hypnotic suggestions on evoked potentials. J. herr,, ment. Dis., 1965, 140: 154-161. BENTE, D. und ITIL, T. M. Zur Wirkung des phenothiazinkoerpers Megaphen auf das menschliche Hirnstrombild. Arzneimittel-Forsch., 1954, 4: 418M23. CHERTOK, L. and KRAMARZ,P. Hypnosis, sleep and electroencephalography. J. nerv. ment. Dis., 1959, 128:227-238, DARROW, C. W., HENRY, C. E., GILl., M., BRENMAN, M, and CONVERSE, M. Frontal-motor parallelism and motor-occipital in-phase activity in hypnosis~ drowsiness and sleep. Eleetroenceph. olin. Neurophysiol.. 1950, 2: 355. Electroenceph. clin. Neurophysiol., 1972, 33:361 368
367
QUANFITATIVE EEG ANALYSIS DURING HYPNOSIS DIA\IANr, J., DUFEK, M.. HOSKOVEC, J., KRIg'roF, M., PEK~REK. V., ROTH, B. and VELEK, M. An electroencephalographic study of the waking state and hypnosis with particular references to subclinical manifestations of sleep activity. Int. J. clin. exp. Hypnos., 1960, 8: 199 212. DYNES. J. B. Objective method for distinguishing sleep from the hypnotic trance. Arch. Neurol. Psychiat. (Chic.), 1947, 57: 84-93. FRANEK, B. und THREN, R. Hirnelektrische Befunde bei gesluftenaktiven Hypnosefibungen. Arch. Psychiat. Nervenkr., 1949, 181: 360-369. GEISSMANN, P., Jus, A. and LUTHE, W. Neurophysiologic and psychophysiologic aspects of the autogenic state. in Proc. 3rd Worht Congr. Psychiat., Vol. lli. University of Toronto Press, Toronto, 1963: 464468. GILYAROVSKIY, V. A., LIVENTSEV, I. M,, SEGAL, Y. Y. and KIRII,I OVA,Z. A. [Electric sleep ( A clinical-physiological hwestigation) .] (English translation). U.S. Joint Publications Research Service, Washington, D.C., 1960, 233 p. GORrON, B. E. The physiology of hypnosis. A review of the literature. Psychiat. Quart., 1949, 23: 317-343, 457 485. HA~ ~JD¢Y, A. M. and MASON, A. A. The effect of hypnotic anaesthesia on cortical responses. J. Neurol. Neurosurg. Psychiat., 1964, 27:300-312. ]IEIMANN, H. und SPOERRI, T. Elektroencephalographische Untersuchungen an Hypnotisierten. Mschr. Psychiat. Neurol., 1953, 125: 261-271. HERN~NDEZ-PE6N, R. and DONOSO, M. Subcortical photically evoked electrical activity in the human waking brain. In Proc. ist lnternat. Cong. Neurol. Sci., Vol. 111. Excerpta Medica, Amsterdam, 1957: 385-396. ISRAtI,, L. et ROHMER, F. Variations dlectroencdphalographiq ues au cours de la relaxation autog6ne et hypnotique. In P. ABOULKERet al. (Eds.), La relaxation. Expansion Scientif. Franqaise, Paris, 1958:88 98. ITH, T. M. Eh, ktroencephalographische Studien bei Psychosen und Psychotropen Medikamenten. Ahmet Salt Matbaasi, 1964, 128 p. ITH., T. M. Electroencephalography and pharmacopsychiatry. In F. A. FREYHAN et al. (Eds.), Clinical psychopharmacology, modern probh, ms q/'pharmacopsychiatJ T. S. Karger, Basel/New York, 1968:163 194. lTn,, T. M. Digital computer analysis of the electroencephalogram during rapid eye movement sleep state in man. J. nerv. ment. Dis., 1970, 150: 20l. JOUVET, M. Photically and somaesthetically subcortical electric activity in the human brain during attention. In Proc. 5th lnternat. Congr. Electroenceph. Clin. NeurophysioL lnternatianal Congress Series No. 37. Excerpta Medica, Amsterdam, 1961: 80-81. Jus, A. and Jus, K. Polygraphic research in autogenic training. In Proc. 3rd World Congr. Psychiat, Vol. 111. University of Toronto Press, Toronto, 1963: 473~82. KAM1YA,J. Operant control of the EEG alpha rhythm and some of its reported effects on consciousness, in C. TAR1 (Ed.), Altered states O/consciousness. John Wiley, N.Y., 1969:507 517. KASAMA~Sb, A. and HIRM, T. An electroencephalographic study on the Zen meditation (zazen). In C. TART (Ed.), .4 Itered states 0[ consciousness. John Wiley, N.Y., 1969 :
489--50l. KRETSCHMER, W. Meditation techniques in psychotherapy. In C. TARa" (Ed.), Altered states ()/' consciousness. John Wiley, N.Y., 1969:219 228. KROGER,W. S. Systems approach for understanding obesity : management by behavioral modification through hypnosis. PsTchiat. Opinion, 1970, 7:7 19. LOOMIS, A. L., HARVEY, E. N. and HOBART. G. Brain potentials during hypnosis. Science, 1936a, 83: 239-241. LOOMIS, A. L., HARVEY, E. N. and HOBART, G. Electrical potentials of the human brain. J. exp. Psyehol., 1936b, 19:249 279. LOOMIS, A. L., HARVEY, E. N. and HOBART, G. A. Cerebral states during sleep as studied by human brain potentials. J. exp. Psychol., 1937, 21:127 144. LUNDHOLM, H. and L(JWENBA('H, H. Hypnosis and the alpha activity of the electroencephalogram. Character andperson, 1942, 11 : 145 149. LUTHE, W., Jus, A. and GEISSMANN,P. Autogenic state and autogenic shift : psychophysiologic and neurophysiologic aspects. Acta psychother. (Basel), 1963, I1 : I 13. MARINKgCO,G., SAGER,D. et KREINDLER,A. Etudes 61ectroencdphalographiques. Le sommeil naturel et le sommeil hypnotic. Bull. Acad. Mdd. (Paris), 1937, I 17:272 276. MORUZZl, G. Reticular influences on the EEG. Electroenceph, clin. Neurophysiol., 1964, 16: 2-17. OKUMA, T., KOGA, E., 1KEDA, K. and SUGIYAMA, H. The EEG of Zen and Yoga practitioners. Electroenceph. olin. Neurophysiol., 1957, Suppl. 9: 51-52. SCHULTZ, J. and LUTHE, W. Autogenic training. In Proc. 3rd World Congr. Psychiat., Vol. I. University of Toronto Press, Toronto, 1961:191 200. SCHWARZ, B, E., BICKFORD, R. G. and RASMUSSEN,W. C. Hypnotic phenomena including hypnotically activated seizures : studies with the electroencephalogram. J. nero. ment. Dis'., 1955, 122:564 574. SERAFETINIDES, E. A. Electrophysiological responses to sensory stimulation under hypnosis. Amer. J. Psrchiat., 1968, 125:150-151. SHAPIRO, D. M. and FINK, M. Quantitative ana(vsis q/' the eleetroencephalogram by digital computer methods'. Psychiatric Research Foundation of Missouri, St. Louis, Mo,. 1966. 118 p.
S1RNA, A. J. An electroencephalographic study of the hypnotic dream. J. Psychol., 1945, 20:109 113. SPIEGEL, H., SHOR, J. and FISHMAN,S. An hypnotic ablation technique for the study of personality development. Psychosom. Med., 1945, 7:273 278. STOJANOW, W. und HHDRICH, R. Das EEG wS_hrend des autogenen Trainings. Psychiat. Neurol. reed. Psyehol. (Lpz.), 1962, 14:13 18. TART, C. (Ed.). Altered states o f consciousness. John Wiley, New York, 1969, 575 p. TIr~('A, J. Etude 61ectroenc6phalographique de deux cas d'anesth6sie hystdrique. J. belye Neurol. P~sTchiat., 1938, 38 : 442-478. ULETT,G. A. lqvpnosisquestionnairvlbrse(l)'atiml. Psychiatric Research Foundation of Missouri. SI. Louis, Mo.. 1970, 4p. ULETT, G. A. and LOEFFEI,,R. G. A nc\~ resonator-mtegrato~ unit lbr the automatic brain wave analyzer, lih, cn'o Eleetroeneeph. e/in. Neurophvsiol., 1972, 33:361 368
368
G . A . ULETT et al.
enceph, clin. Neurophysiol., 1953, 5:113-115. LILETT, G. A., AKPINAR, S. and ITIL, T. M. Investigations of hypnosis utilizing induction by video tape. Psychosomatics, 1971, 12: 250. ULETT, G. A., AKPINAR, S. and ITIL, T. M. Hypnosis: physiological, pharmacological reality. Amer. J. Psychiat., 1972a, 128: 7. ULETT, G. A., AKPINAR, S. and ITIL, T. M. Hypnosis by video tape. Int. J. clin. exp. Hypnos., 1972b, 20: 46. VESELY, L. [EEG recording of the hypnotic state.] (in Czech). Neurol. psychiat. ~s., 1950, 13: 210-219. WILSON, N. J. Neurophysiologic alterations with hypnosis.
Dis. nerv. Syst., 1968, 29: 618-620. YEAGER, C. L. and LARSON, A. A study of alpha desynchronization in the electroencephalogram, utilizing hypnotic suggestion. Electroenceph. clin. Neurophysiol., 1958, I0: 193-194. ZANOCCI, G. and GORI, E. Observation on the psychophysiological variations related to hypnotic behaviour. Eleetroenceph. olin. Neurophysiol., 1963, 15: 920-921. ZmMUNO, V. Some physiological characteristics of natural and hypnotic sleep in man. Physiol. bohemoslot,., 1964, 13: 196-201.
Reference: ULETT, G. A., AKPINAR,S. and ITIL, T. M. Quantitative EEG analysis during hypnosis. Electroenceph. clin. Neurophysiol., 1972, 33: 361-368.