Electrophysiological Alterations During Hypnosis for Ego-Enhancement: A Preliminary Investigation

American Journal of Clinical Hypnosis, Apr 2004 by Stevens, Larry, Brady, Brian, Goon, Angela, Adams, Deanna, Et al

The specific hypotheses of the present investigation are that (1) across the induction, deepening, and suggestions stages of an hypnosis process designed to closely replicate that found in a clinical setting, participants will show progressive increases in frontal theta and beta (including components of 40 Hz gamma) EEG frequencies with a return to baseline values at termination; (2) these changes in theta and beta frequencies will be greater for highly and very highly hypnotizable participants than for moderates or lows, and moderates will show greater changes than will lows. Furthermore, (3) it is predicted that highs and very highs will show their most remarkable increases in both theta and beta EEG frequencies across the suggestions phase of hypnosis, during directed attention to visual imagery ego-enhancing suggestions.

Method

Participants

Introduction to Psychology Subject Pool volunteers at Northern Arizona University were invited to participate in a study for extra class credit on "Hypnosis and Brainwaves." The study was implemented in three phases. In Phase I, participants were administered, in groups of up to 10 individuals, an Informed Consent Form, a Demographic Questionnaire, and three paper-and-pcncil correlates of hypnotic susceptibility: the Tellegen Absorption Scale (TAS), the Creative Imagination Scale (CIS), and the Imaginative Involvement Scale (HS)1. Two hundred students participated in this phase of the study. After completion of these instruments, 121 (61%) participants volunteered to continue on to Phase II, during which they were individually administered the Stanford Hypnotic Susceptibility Scale: Form C (SHSS:C). Sixty of the Phase II participants then volunteered to continue on to Phase III during which the hypnosis and EEG study was conducted. After each phase, participants were given the suitable number of extra credit participation points for that phase of the study.

Although participants in this study were not clinical patients per se, the EEG recording process was conducted within a clinical setting and participants were taken through a therapeutic hypnosis process designed to induce a deep hypnotic state and to offer suggestions to enhance self-esteem and coping abilities and to change perspective on an important aspect of their lives. Many of the participants reported profound personal insights and/or moving emotional experiences as a result of the hypnosis process.

Questionnaires

Demographic Questionnaire. Participants were asked to identify their age; gender; year in college; prior experience with hypnosis, meditation, formal relaxation training, and EEGs; episodes of head injury and unconsciousness; medications currently taking; and any current drug use. Additionally, as noted above, participants were initially screened on the following three correlates of hypnotic susceptibility.

Tellegen Absorption Scale. The TAS is a 34-item true-false questionnaire designed to assess some of the personality characteristics of hypnotizability, including "a heightened sense of reality of the attentional object," "an imperviousness to normal distracting events," and "an altered sense of reality in general and of the self in particular" (Tellegen & Atkinson, 1974, p. 274). Tellegen and Atkinson (1974) reported correlations of .27 and .43 with two versions of the Group Scale of Hypnotic Susceptibility and .42 with Field's Hypnotic Depth Scale. Test-retest and split-half reliabilities over .80 have been reported for the TAS (Roberts, Schuler, Bacon, Zimmerman, & Patterson, 1975). Scoring of the TAS is from 0-34. Because TAS scores for the present study were negatively skewed (Skew = -.353), cutoffs for absorption level were established by percentiles, with scores from 0-19 being low absorption, 20-25 being moderate, and 26-34 being high absorption for this study. This adjustment in the TAS cutoffs differs slightly from the category ranges identified on the basis of normally distributed data but better accommodates the small number of very low scores on this measure obtained with our subject pool.