Biomedical subjects

A Barabasz

Publications and source records attributed to A Barabasz.

9 recordsLinked to original sources

PubMed2001

EEG P300 event-related markers of hypnosis.

Barabasz, Barabasz, Jensen, Calvin, Trevisan, and Warner (1999) showed that, when subjects are stringently selected for hypnotizability and responses are time locked to events, robust markers of hypnotic responding emerge that reflect alterations in consciousness that correspond to subjects' subjective experiences of perceptual alteration. To further test the Barabasz et al. (1999) hypothesis, we obtained EEG visual P300 event-related potentials (ERPs) from 20 high- and low-hypnotizable subjects. The effects of positive obstructive and negative obliterating instructions were tested during waking and alert hypnotic conditions. High-hypnotizables showed greater ERP amplitudes in response to the negative hallucination condition and lower ERP amplitudes in response to the positive obstructive hallucination when compared to the low-hypnotizables. Contrary to socio-psychological or role play conceptualizations, the hypnotic induction resulted in specific psychophysiological responses which could not be produced by waking imagination or by the lows who were trying to mimic hypnotic responding.

Adult↗

PubMed2000

Hypnosis and distraction differ in their effects on cold pressor pain.

On the bases of Hilgard's neodissociation theory and Spano's (1982) sociocognitive theory, volunteers stringently selected for high (N = 10) and low (N = 10) hypnotizability were exposed to a cold pressor pain test during counterbalanced conditions of waking relaxation, distraction, and hypnosis. To better discriminate between hypnosis and distraction conditions, a new distraction procedure was developed involving the memorization of a sequence of colored lights. High hypnotizables showed significantly greater pain relief for hypnosis versus distraction or waking relaxation conditions. High hypnotizables also demonstrated significantly greater pain relief than low hypnotizables in response to hypnosis. Quantitative electroencephalographic (EEG) findings showed significantly greater high theta (5.5-7.5 Hz) activity for highs as compared to lows at parietal (P3) and occipital (01) sites during both hypnosis and waking relaxation conditions. The findings fail to support the socio-cognitive conceptualization of hypnotic behavior while providing additional evidence supporting the neo-dissociation theory and state based theories of hypnosis in general.

Cold Temperature↗

PubMed2000

Hypnosis as an empirically supported clinical intervention: the state of the evidence and a look to the future.

Drawing on the literature reviews of this special issue of the International Journal of Clinical and Experimental Hypnosis (2000), this article summarizes the evidence for the effectiveness of hypnosis as an empirically supported clinical intervention. As a whole, the clinical research to date generally substantiates the claim that hypnotic procedures can ameliorate some psychological and medical conditions, as judged against the Chambless and Hollon methodological guidelines. In many cases, these clinical procedures can also be quite cost-effective. It is probable that with some key empirical refinement a number of other hypnosis treatment protocols will have sufficient empirical documentation to be considered "well-established." However, it is noted that the Chambless and Hollon guidelines are not particularly well-suited for assessing hypnosis' impact when used adjunctly with other interventions. The article concludes with recommendations regarding the efficacy questions that need to be more fully addressed empirically and offers methodological guidelines for researchers and practitioners.

Anxiety↗

PubMed1999

Brief hypnosis substitutes for alprazolam use in college students: transient experiences and quantitative EEG responses.

We sought to determine: 1) whether a simple hypnotic induction with an alprazolam experience derived suggestion could recreate the subjective effects of alprazolam (Xanax), 2) whether the effects of alprazolam are greater than the effects of hypnosis plus this suggestion, and 3) whether the effects of hypnosis plus this suggestion were greater than the relaxation effects produced by hypnosis alone. High and low hypnotizable student volunteer subjects (Ss) ingested 1 mg of alprazolam. A hypnotic suggestion was developed on the basis of their reported reactions to alprazolam. Four days later the same Ss were exposed to hypnosis only and hypnosis plus the alprazolam experience based suggestion conditions in counterbalanced order. Ss exposed to the hypnosis plus suggestion condition demonstrated greater levels of relaxation as measured by the tension-anxiety scale of the Profile of Mood States (POMS) (Eichman & Umstead, 1971) than in the alprazolam condition or the hypnosis only condition. High hypnotizables showed significantly greater levels of relaxation than the low hypnotizables in each of the three conditions (hypnosis plus suggestion, hypnosis only, alprazolam only). EEG data showed frontal and occipital sites were specifically involved in both the alprazolam and the hypnotic suggestion conditions. The findings indicate a basis for the use of hypnosis as a substitute for sedative drug use. Limitations and implications for clinicians are discussed.

Adult↗

PubMed1999

Cortical event-related potentials show the structure of hypnotic suggestions is crucial.

Electroencephalographic cortical event-related potentials (ERPs) are affected by information processing strategies and are particularly appropriate for the examination of hypnotic alterations in perception. The effects of positive obstructive and negative obliterating instructions on visual and auditory P300 ERPs were tested. Twenty participants, stringently selected for hypnotizability, were requested to perform identical tasks during waking and alert hypnotic conditions. High hypnotizables showed greater ERP amplitudes while experiencing negative hallucinations and lower ERP amplitudes while experiencing positive obstructive hallucinations, in contrast to low hypnotizables and their own waking imagination-only conditions. The data show that when participants are carefully selected for hypnotizability and responses are time locked to events, rather robust physiological markers of hypnosis emerge. These reflect alterations in consciousness that correspond to participants' subjective experiences of perceptual alteration. Accounting for suggestion type reveals remarkable consistency of findings among dozens of researchers.

Cerebral Cortex↗

PubMed1998

Hypnosis enhances recall memory: a test of forced and non-forced conditions.

Visual memory recall in hypnosis was investigated. To address criterion shift problems in previous studies, both forced and non-forced recall procedures were used. Previous methodological weaknesses with regard to hypnotizability and hypnotic depth were also addressed. Over 300 volunteers were screened for hypnotizability using the Harvard Group Scale of Hypnotic Susceptibility: Form A (Shor & Orne, 1962). Final high and low hypnotizability groups were selected using the Stanford Hypnotic Susceptibility Scale: Form C (Weitzenhoffer & Hilgard, 1962). Participants in each hypnotizability group were randomly assigned to either forced or non-forced recall conditions and to hypnosis or waking conditions. Participants were shown 60 slides of line drawings and then tested immediately in 3 recall periods. Analysis of variance results showed that those exposed to hypnosis and to a forced recall procedure were significantly more confident of their responses to correct items than those exposed to a non-forced recall procedure or a waking condition. Participants exposed to hypnosis and forced recall procedures recalled more correct items than those exposed to a waking condition. The findings support the hypermnesic effects of hypnosis when participants are required to provide a fixed number of responses.

Adult↗

PubMed1995

Effects of hypnosis on the immune response: B-cells, T-cells, helper and suppressor cells.

This study tested the effects of hypnosis on the immune response. High and low hypnotizable Ss were exposed to hypnosis, relaxation or control conditions. Blood samples obtained before treatment and twice thereafter were subjected to flow cytometry analysis. Significant alteration of the immune response as measured by B-cells and helper T-cells was shown only for highly hypnotizable Ss exposed to hypnosis.

Adolescent↗

PubMed1993

Restricted environmental stimulation technique improves human performance: rifle marksmanship.

This study controlled for relaxation and guided imagery confounds noted in much previous research on enhancement of human performance using the restricted environmental stimulation technique (REST). Dry flotation REST was used where subjects lay ("floated") on a salt-water-filled bladder in a sound-attenuated, light-free chamber. 9 men and 3 women in a rifle marksmanship training course, exposed to dry-flotation REST, showed significantly higher rifle marksmanship scores than the university students who as matched controls were exposed to relaxation (9 men and 3 women). Further, only the former showed a significant pre- to posttest improvement in scores, which suggests REST's positive effects on marksmanship go beyond the induction of relaxation by hypnosis. The results support hypotheses summarized in 1982 by Barabasz regarding potentiation by REST of internally generated imagery and subsequent improvement observed in a nonREST posttest environment.

Adult↗

PubMed1991

Effects of experimental context, demand characteristics, and situational cues: new data.

When in 1964 stress induced by Restricted Environmental Stimulation (REST) was publicized, Orne and Scheibe showed "sensory deprivation" effects could be produced merely by manipulating contextual cues. Since REST is now widely regarded as beneficial, it seemed appropriate to reexamine these early findings. Stringently replicating Orne and Scheibe's procedures, 10 subjects were exposed to conditions designed to generate expected REST effects. Conditions for 10 controls suggested that nothing was expected to happen. Analyses did not confirm earlier findings as no significant difference was found between experimental and control groups on any measure. A postexperimental inquiry identified positive attitudes toward REST. The specific experimental context, demand characteristics, and situational cues did not elicit responses inconsistent with the general sociopsychological context. Researchers are cautioned about attributing causality to contextual cues because context exists merely at a correlative level with data collection.

Adaptation, Psychological↗