Hypnosis in highly susceptible subjects increased posterior alpha power and posthypnosis theta activity compared to low susceptible subjects, indicating alpha indexes hypnotic susceptibility.
Observational (n=16)
Does hypnosis alter narrow band theta and alpha frequencies differently in high versus low hypnotically susceptible subjects?
Theta activity indexes relaxation, whereas alpha activity indexes the hypnotic experience and susceptibility.
Narrow band theta and alpha activity were recorded over anterior and posterior sites before, during, and after hypnosis in high and low hypnotically susceptible subjects (N = 16). In theta, high susceptibles had greater activity posthypnosis, otherwise there were no group differences. These findings common to low and high susceptibles suggest that theta is an index of relaxation that continues after hypnosis in highs. In alpha in high susceptibles, posterior power increased from the prehypnosis to hypnosis conditions and decreased posthypnosis. Exactly the converse effects were seen in lows. Furthermore, highs had greater alpha power than lows during both prehypnosis and hypnosis conditions, demonstrating an association of alpha with hypnotic susceptibility. The results indicate that, whereas theta indexes relaxation, alpha indexes the hypnotic experience and susceptibility.
Williams et al. (Sun,) conducted a observational in Hypnotic susceptibility (n=16). Hypnosis vs. Low hypnotically susceptible subjects and prehypnosis baseline was evaluated on Narrow band theta and alpha activity over anterior and posterior sites. Hypnosis in highly susceptible subjects increased posterior alpha power and posthypnosis theta activity compared to low susceptible subjects, indicating alpha indexes hypnotic susceptibility.