Hypnotic analgesia: A preliminary investigation of quantitated hemispheric electroencephalographic and attentional correlates.

The effects of hypnotically induced analgesia were studied in 6 undergraduate Ss rated as moderately hypnotizable and 5 Ss rated as highly hypnotizable. Subjective pain reports and EEG activation were recorded during 1-min periods of cold-pressor stimulation. Both groups reported decreased pain during hypnosis, but the decrease was greater for the highly hypnotizable group. During hypnotic analgesia, immersion of either the right or the left hand in ice water was correlated with contralateral EEG activation for moderately hypnotizable but not for highly hypnotizable Ss. Lack of contralateral shift was correlated for the whole sample and within groups with success on an attentional task related by previous research to hypnotizability as well as with reports of reduced pain. (12 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Randomized clinical trial of local anesthetic versus a combination of local anesthetic with self-hypnosis in the management of pediatric procedure-related pain.

A prospective controlled trial was conducted to compare the efficacy of an analgesic cream (eutectic mixture of local anesthetics, or EMLA) with a combination of EMLA with hypnosis in the relief of lumbar puncture-induced pain and anxiety in 45 pediatric cancer patients (age 6-16 years). The study also explored whether young patients can be taught and can use hypnosis independently as well as whether the therapeutic benefit depends on hypnotizability. Patients were randomized to 1 of 3 groups: local anesthetic, local anesthetic plus hypnosis, and local anesthetic plus attention. Results confirmed that patients in the local anesthetic plus hypnosis group reported less anticipatory anxiety and less procedure-related pain and anxiety and that they were rated as demonstrating less behavioral distress during the procedure. The level of hypnotizability was significantly associated with the magnitude of treatment benefit, and this benefit was maintained when patients used hypnosis independently. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Comparison of hypnosis and distraction in severely ill children undergoing painful medical procedures.

An ethnically diverse sample of high and low hypnotizable children (N?=?27) suffering from cancer or blood disorders and their parents were trained to use both distraction and hypnosis to reduce pain and anxiety. Measures of pain and anxiety were obtained from the children and their parents. Independent raters also judged participants' video-taped distress responses. Data were collected during painful medical procedures, for baseline, distraction, and hypnosis conditions. Supporting E. R. Hilgard's (1977, 1992) neodissociation theory, hypnotizable children showed significantly lower pain, anxiety, and distress scores in response to hypnosis in contrast to low hypnotizable children. Distraction produced significant positive effects for observer-rated distress scores for the low hypnotizable children. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of active alert and relaxation hypnotic inductions on cold pressor pain.

Contrasted relaxation and active alert hypnotic inductions with or without a specific suggestion for cold pressor pain analgesia. Groups of high (n?=?38) and low (n?=?27) hypnotizable Ss were tested; hypnotizability had been determined from results of the Stanford Hypnotic Susceptibility Scale, Form C. Cold pressor pain data were obtained after counterbalanced exposure to relaxation and active alert inductions. Highly hypnotizable Ss demonstrated lower pain scores than did low hypnotizable ones. Pain reports did not differ between induction conditions. Highly hypnotizable Ss given an analgesic suggestion showed lower pain scores than did those exposed only to hypnosis. The findings, conceptualized within E. R. Hilgard's (1977) neodissociation theory, show that relaxation is not necessary for hypnotic analgesia. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

An event-related potential investigation of posthypnotic recognition amnesia.

Forty-two individuals selected for high hypnotizability or for low hypnotizability were taught lists of words during hypnosis and assessed for recognition following hypnosis using event-related potential (ERP) procedures, both before and after the cue to reverse amnesia. A subgroup of low-hypnotizable participants were asked to simulate hypnotic behavior. All participants had larger late positive component (LPC) amplitudes to learned than to unlearned words, regardless of whether amnesia was reported. The highly hypnotizable participants who reported recognition amnesia, however, had significant changes in attention-related (P1 and N1) and recognition-related (N400 and LPC) ERP component amplitudes as a function of whether amnesia was reported. These data suggest that posthypnotic amnesia may involve alterations in the processes of attention, selection, and accessibility. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Hypnotizability and automaticity: Toward a parallel distributed processing model of hypnotic responding.

Tested a hypothesis from parallel distributed processing theory that highly hypnotizable Ss have greater connection strengths along verbal pathways and would show greater Stroop effects than low hypnotizable Ss. Using the paradigm from J. Cheesman and P. M. Merikle (see record 1989-03722-001) which varied cue visibility and probability, automatic and strategic effects on Stroop performance were assessed. Compared with 9 low and 9 moderately hypnotizable Ss, 9 highly hypnotizable ones showed significantly greater Stroop effects for both visible- and degraded-word trials. No strategic differences emerged for the 3 hypnotizability groups. These findings support the contention that highly hypnotizable persons have stronger verbal connection strengths than their moderately and low susceptible counterparts, and they may account for highly hypnotizable persons' propensity to disregard personal attributions and label their responses in hypnosis as being involuntary. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Enhancing visual memory: Trying hypnosis, trying imagination, and trying again.

Tested visual recall memory of high (n?=?24) and low (n?=?24) hypnotizable undergraduates (screened under the Harvard Group Scale of Hypnotic Sensibility and the Stanford Hypnotic Sensibility Scale) for black and white line drawings of common objects in either hypnosis, imagination, or control conditions. Memory performance in terms of both correct and incorrect items increased appreciably across the recall tests. Neither hypnosis nor imagination enhanced recall beyond that of normal repeated testing. Hypnotizability was not related to the amount of correct material recalled but was related to the amount of incorrect material reported. High hypnotizable Ss in the hypnosis condition were more likely than other Ss to confidently rate the incorrect material as correct. Findings are discussed in terms of the impact of hypnosis on and the relevance of hypnotizability to enhancing visual memory. (27 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

EEG activity and heart rate during recall of emotional events in hypnosis: relationships with hypnotizability and suggestibility

The purpose of the present research was to find physiological and cognitive correlates of hypnosis, imaginative suggestibility and emotional experiences. After the administration of a standard hypnotic induction, the EEG and heart rate (HR) were recorded during self-generated happy and sad emotions using a relaxation condition as a control. Physiological recordings were also obtained during three eyes-open and eyes-closed baseline periods: (1) waking rest; (2) early-rest in hypnosis (just after the hypnotic induction); (3) late-rest hypnosis (at the end of hypnotic condition). EEG was recorded at frontal (F3, F4), central (C3, C4), and posterior sites (middle of O1-P3-T5 and O2-P4-T6 triangles). Using log transform of mean spectral amplitude, eight EEG frequency bands (4-44 Hz) were evaluated. High hypnotizable subjects, as compared to the lows, produced a higher theta1 amplitude (4-6 Hz) across both left- and right-frontal and right-posterior areas. These subjects also produced smaller alpha1 amplitude (8.25-10 Hz) over both left and right frontal recording sites. High suggestible subjects, during resting conditions, disclosed higher theta2 (6.25-8 Hz) and alpha1 amplitudes in eyes-closed as compared to an eyes-open condition than did low suggestible subjects. High suggestible subjects also showed, in hypnosis-rest condition, higher 40-Hz amplitudes (36-44 Hz) and HR activity than did low suggestible subjects. Hypnotizability and not suggestibility was found to moderate emotional processing: high hypnotizable individuals self-reported greater levels of emotional experiences than did low hypnotizables especially in terms of negative emotion. High hypnotizables, during processing of emotional material, also disclosed opposite 40-Hz hemispheric asymmetries over anterior and posterior regions of the scalp. These subjects during happiness showed an increased production of 40-Hz activity in the left frontal and central regions of the scalp, while during sadness they showed an increased activity in the right central and posterior regions. The hemispheric asymmetries for relaxation condition were similar, but less marked, to those obtained for happiness. No significant interactions involving both hypnotizability and imaginative suggestibility were found for physiological variables considered in this study. This demonstrates that hypnotizability and suggestibility reflect different underlying psychophysiological activities.     

Analgesic effects of posthypnotic suggestions and virtual reality distraction on thermal pain.

The individual and combined effects of posthypnotic suggestion (PHS) and virtual reality distraction (VRD) on experimentally induced thermal pain were examined using a 2 × 2, between-groups design. After receiving baseline thermal pain, each participant received hypnosis or no hypnosis, followed by VRD or no VRD during another pain stimulus. Consistent with the hypothesis that hypnosis and VRD work via different mechanisms, results show that posthypnotic analgesia was moderated by hypnotizability but VRD analgesia was not. The impact of PHSs for analgesia was specific to high hypnotizables, whereas VRD was effective independent of hypnotizability. Results also show a nonsignificant but predicted pattern for high hypnotizables: Audio hypnosis combined with VRD reduced worst pain 22% more and pain unpleasantness 25% more than did VRD alone. Theoretical and clinical implications are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Literalism as a marker of hypnotic "trance": Disconfirming evidence.

The responses given by highly hypnotizable, hypnotic subjects and those of unhypnotizable subjects who simulated hypnosis to questions of the type, "Do you mind telling me your name?" and "Do you mind standing up?" were contrasted. The purpose was to examine M. H. Erickson's (1980) assertion that literalism (answering "yes" or "no" verbally or nonverbally without any cognitive elaboration) is a marker of hypnotic "trance." Simulators exhibited a greater rate of literalism than hypnotic "virtuosos" (i.e., extreme scorers on both group and individual hypnotizability measures). Hypnotized subjects and nonhypnotized subjects approached in the campus library responded comparably. Because less than a third of hypnotic virtuosos responded literally, our results strongly refuted Erickson's assertion that literalism is a cognitive feature of hypnosis. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Memory liabilities associated with hypnosis: does low hypnotizability confer immunity?

Retrospective analyses of data from the authors' program of research on hypnosis and memory are presented, with special emphasis on effects observed among low hypnotizable individuals. In Experiment 1, participants completed seven forced-recall trials in an attempt to remember a series of pictures that had been shown 1 week earlier. For half the participants, the middle five trials were carried out using hypnotic procedures; the remaining participants performed all recall attempts in a motivated waking condition. Hypnosis failed to enhance correct recall for either high or low hypnotizable participants beyond the hypermnesia and reminiscence effects associated with repeated retrieval attempts over time. However, whereas high hypnotizable participants produced substantial numbers of confident recall errors (i.e., intrusions) independent of the use of hypnosis, low hypnotizable participants exposed to hypnotic procedures reported significantly more intrusions than their counterparts in the waking condition. In Experiment 2, participants were asked to identify whether specific recollections, reported during two forced-interrogatory recall tests conducted 1 week earlier, had originated in the first or second of those tests. A general bias to misattribute previously reported recollections to the first of two recall occasions was observed; however, the effect was greatest among low hypnotizables who had undergone the second recall attempt in hypnosis. The findings imply that highly hypnotizable individuals are not unique in their vulnerability to distortions of memory induced by hypnotic techniques. Individuals of lesser hypnotic capacity also manifest memory alterations when exposed to such procedures.     

Hypnotic susceptibility as related to gestalt closure tasks.

Studied the relationship of gestalt closure tasks to hypnotizability (Harvard Group Scale of Hypnotic Susceptibility and Stanford Hypnotic Susceptibility Scale) as a test of the hypothesis that the more highly hypnotizable do better on a task of holistic visuospatial functioning than those less responsive to hypnosis. Several other cognitive tasks were included. Four studies were conducted with 125 male and 106 female high school and college students. In Study I, high hypnotizables scored significantly higher than low hypnotizables on the gestalt closure tasks, but there were no significant correlations between hypnotizability and the other cognitive tasks. In Studies II and III, females showed significant correlations between hypnotic susceptibility and gestalt closure scores. In Study IV, a significant correlation between hypnotic susceptibility and gestalt closure was found for males. Results are consistent with studies of different types of cognitive functioning (hemispheric preference, creativity, attentional distribution, imaginative involvement, and absorption), all indicating differences in cognitive abilities associated with high hypnotizability. (33 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Hypnotizability as a function of repression, adaptive regression, and mood.

40 male undergraduates individually participated in a personality assessment session and hypnotic susceptibility session (using the Stanford Hypnotic Susceptibility Scale). Scales derived from the Rorschach test were used to measure the personality traits of repressive style and adaptive regression. The transitory variable, mood just prior to hypnosis, was assessed by a mood index derived from the Nowlis Mood Adjective Check List (MACL). Results show that hypnotizability was a significant interactive function of repressive style and mood (Ss high in repressive style and in bright moods tended to be hypnotizable) but not of adaptive regression and mood. Mood as a main variable was significantly related to hypnotizability. The MACL Surgency scale (which contains the adjectives carefree, playful, and witty) was the best single predictor of hypnotizability, accounting for 25% of the variance. Neither personality trait as a main variable was related to hypnotizability. (33 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Hypnosis treatment of clinical pain: understanding why hypnosis is useful

Clinical and experimental research literature indicates hypnosis is very useful for severe and persistent pain, yet reviews suggest hypnosis is not widely used. To encourage more widespread clinical application, the author reviews recent controlled clinical studies in which hypnosis compares favorably with other interventions; links advances in understanding endogenous pain modulation to a neurophysiologic view of hypnosis and hypnoanalgesia; relates the neurophysiology of hypnoanalgesia to management of chronic pain; challenges the view that hypnotic pain control is only for the highly hypnotizable patient; and raises issues about how people learn to control pain with hypnosis. Training in hypnotic analgesia may usefully enhance nervous system inhibitory processes that attenuate pain.     

Posthypnotic amnesia for material learned before hypnosis

The impact of a suggestion for posthypnotic amnesia on material learned either before or during hypnosis was investigated across 2 experiments. In Experiment 1, very high, high, and low hypnotizable participants learned a word list either before or immediately after a hypnotic induction. During hypnosis, participants were given a suggestion for posthypnotic amnesia for the word list. After hypnosis, they were tested on recall, word-fragment, and word-recognition tasks. Experiment 2 replicated and extended Experiment 1 through application of the real-simulating paradigm. Across the 2 experiments, there was no difference in the performance of participants who learned the word list either before or during hypnosis. Although amnesia on direct memory measures was associated with high hypnotizability (Experiment 1), an explanation based on demand characteristics could not be excluded (Experiment 2). The implications of these findings for the use of post-hypnotic amnesia as a laboratory analog of disorders of autobiographical memory are discussed.     

EEG asymmetry and heart rate during experience of hypnotic analgesia in high and low hypnotizables

This study evaluates the effects of hypnotic analgesia and hypnosis on bilateral EEG activity recorded from frontal, central and posterior areas during three painful electrical stimulation conditions: waking, hypnosis/no-analgesia, hypnosis/analgesia. Eight high-hypnotizable and eight low-hypnotizable (right handed) subjects participated in the experiment. The following measures were obtained: pain and distress tolerance ratings; EEG spectral amplitudes for the frequency bands: delta (0.5-3.75 Hz), theta 1 (4-5.75 Hz), theta 2 (6-7.75 Hz), alpha 1 (8-9.75 Hz), alpha 2 (10-12.75 Hz), beta 1 (13-15.75 Hz), beta 2 (16-31.75 Hz), total band (0.5-31.75 Hz), '40-Hz' (36-44 Hz); cardiac interbeat interval (ms); mid-frequency and high-frequency peaks from power spectral analysis of heart period variability. During hypnosis/analgesia, high hypnotizable subjects displayed significant reductions in pain and distress scores compared to hypnosis/no-analgesia and waking conditions. In each experimental condition these subjects displayed significant lower total and beta 1 amplitudes compared to low hypnotizables. High hypnotizables, on central and posterior recording sites, during both hypnosis/analgesia and hypnosis/no-analgesia conditions also showed total and delta EEG amplitude reductions in both hemispheres and a theta 1 amplitude reduction in the left hemisphere. However, for total, delta and beta 1 bands in the hypnosis/analgesia condition the amplitude reduction was more pronounced in the right hemisphere as shown by hemispheric asymmetry in favor of the left hemisphere. Low hypnotizables, on posterior recording sites, displayed a delta amplitude reduction during hypnosis/no-analgesia and hypnosis/analgesia conditions. These subjects also showed, for all recording sites, a reduction in theta 1 amplitude during hypnosis/no-analgesia compared to the waking condition. Lows, however, failed in evidencing amplitude differences between hypnosis/no-analgesia and hypnosis/analgesia conditions. During hypnotic analgesia the hemispheric asymmetry found in high hypnotizables was parallel to a significant reduction in the spectral mid-frequency peak of heart period variability which indicated a decrease in the level of sympathetic activity. In contrast, during hypnosis/no-analgesia the EEG amplitude reduction was not paralleled by a decrease in sympathetic activity.     

Goal-directed fantasy, hypnotic susceptibility, and expectancies.

We conducted an initial screening session in which hypnosis was presented as a "test of imagination" and administered with other imagination measures. In a 2nd session, we instructed high- and low-hypnotizable Ss to imagine along with suggestions but to resist responding to motoric suggestions. Ss received either instructions to use goal-directed fantasies (GDFs) or no facilitative instructions. Sizable individual difference effects were secured. Hypnotizable Ss exhibited more suggestion-related movements and reported greater involuntariness than did low-hypnotizable Ss. With GDF instructions, low- and high-hypnotizable Ss reported equivalent GDF absorption and frequencies. However, hypnotizable Ss exhibited greater responsiveness and reported greater involuntariness than did those low in hypnotizability, even when their GDFs were equivalent. Thus, no support was generated for the hypotheses that sustained, elaborated suggestion-related imagery mediates response to suggestion or that absorption in suggestions is of particular importance for low-hypnotizable Ss. Findings support the hypothesis that expectancies mediate the relation between imagination, involuntariness, and responding. Hypnotizable imagining Ss exhibited greater responsiveness than a comparable sample of Ss did in a previous countersuggestion study (Lynn, Nash, Rhue, Frauman, & Stanley, 1983). (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Hypnosis, suggestion, and placebo in the reduction of experimental pain.

Two experiments compared placebo and hypnotic analgesia in high and low hypnotizable subjects. Experiment 1 demonstrated that hypnotic and placebo analgesia were equally ineffective in low hypnotizables, but that hypnotic analgesia was much more effective than placebo analgesia in high hypnotizables. Experiment 2 replicated these results, but also included low and high hypnotizables who were given a nonhypnotic suggestion for analgesia. Both the low and high hypnotizables in this group reported greater suggested than placebo analgesia and as much suggested analgesia as high hypnotizable hypnotic subjects. Both experiments found substantial discrepancies between the amount of pain reduction subjects expected from the various treatments and the amount of pain reduction they actually reported following exposure to those treatments. In Experiment 2, subjects in all treatments who reduced reported pain engaged in more cognitive coping and less catastrophizing than those who did not reduce pain. Theoretical implications are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Mediators of a brief hypnosis intervention to control side effects in breast surgery patients: Response expectancies and emotional distress.

Objective: The present study was designed to test the hypotheses that response expectancies and emotional distress mediate the effects of an empirically validated presurgical hypnosis intervention on postsurgical side effects (i.e., pain, nausea, and fatigue). Method: Women (n = 200) undergoing breast-conserving surgery (mean age = 48.50 years; 63% White, 15% Hispanic, 13% African American, and 9% other) were randomized to a hypnosis or to an attention control group. Prior to surgery, patients completed assessments of hypothesized mediators (response expectancies and emotional distress), and following surgery, patients completed assessments of outcome variables (pain, nausea, and fatigue). Results: Structural equation modeling revealed the following: (a) Hypnotic effects on postsurgical pain were partially mediated by pain expectancy (p p = .12); (b) hypnotic effects on postsurgical nausea were partially mediated by presurgical distress (p = .02) but not by nausea expectancy (p = .10); and (c) hypnotic effects on postsurgical fatigue were partially mediated by both fatigue expectancy (p = .0001) and presurgical distress (p = .02). Conclusions: The results demonstrate the mediational roles of response expectancies and emotional distress in clinical benefits associated with a hypnotic intervention for breast cancer surgical patients. More broadly, the results improve understanding of the underlying mechanisms responsible for hypnotic phenomena and suggest that future hypnotic interventions target patient expectancies and distress to improve postsurgical recovery. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cognitive factors in hypnotic susceptibility.

Conducted 3 pilot studies with a total of 50 undergraduates to test 3 hypotheses derived from M. Gill and M. Brenman's (see pa, vol. 34:5325) study of hypnosis: (a) strong automatizers are less susceptible to hypnosis, (b) highly hypnotizable ss are more prone to distraction, and (c) highly hypnotizable ss produce more amorphous figure drawings. Performances on the stanford hypnotic susceptibility scale, the stroop color-word test, and the draw-a-person test support only the 2nd and 3rd hypotheses. Further testing using 4 verbal and 6 visual-motor measures on 40 male and 33 female undergraduates support the 2nd and 3rd hypotheses only for females. Analysis of pilot study data indicate that sex differences may have been present there also. (PsycINFO Database Record (c) 2010 APA, all rights reserved)