title: EEG asymmetry and heart rate during experience of hypnotic analgesia in high and low hypnotizables.
abstract: 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.
authors.affiliation: Department of Psychology, University of Rome La Sapienza, Italy.
authors.forename: V
authors.initials: V
authors.lastname: De Pascalis
authors.forename: M
authors.initials: M
authors.lastname: Perrone
mesh_terms: D000328:Adult; D001007:Anxiety / Q000523:psychology; D001288:Attention / Q000502:physiology; D004558:Electric Stimulation; D004562:Electrocardiography; D004569:Electroencephalography; D004585:Electrooculography; D005260:Female; D007839:Functional Laterality / Q000502:physiology*; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D006991:Hypnosis, Anesthetic; D008297:Male; D010146:Pain / Q000503:physiopathology; D009435:Synaptic Transmission / Q000502:physiology