For the first time, we have measured EEG signals during Reiki. EEG signals of 30 persons during receiving Reiki in two groups of Reiki and Placebo were collected. Nonlinear features such as fractal dimension, Lyapunov exponent; approximate entropy and phase space plot of data set were extracted. Finally, t-tests were calculated to compare target features. The results showed that there was a significant increase in nonlinear features in the Reiki group compared to the Placebo group and these groups significantly separated from each other. The increases showed the raising of active functional processing in the brain and complexity during the Reiki. The limited amount of fractal dimension and positive Lyapunov exponent in Reiki group compared with the placebo shows that EEG signal has a chaotic behavior. Moreover, we used SVM classifier to separate these groups; the maximum classification accuracy was obtained around 80.5%. We measured the emotional states of the subjects on a Likert scale (from before to after the Reiki) and it was shown that senses of relaxation were increased to a higher degree during Reiki than during the Placebo condition.

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