ECG
No significant difference was observed in the autonomic state between groups and within conditions. Seemingly different findings with respect to other studies can be accounted for by differences in the experimental design. The absence of significant differences between groups in the closed eyes awake condition (R) lasting 3 minutes accords with the observation that significant differences between highs and lows appear during longer-lasting relaxation (15 minutes) (Santarcangelo et al., 2012). Moreover, a decrease in the absolute LF power and an increase in the absolute HF power have been observed during a 20 minutes neutral hypnosis, with consequent reduction of the LF/HF ratio (Santarcangelo et al., 1992). Finally, in other studies (De Benedittis et al., 1994), decreasing normalized LF and increased normalized HF have been observed during the second 10 minutes of a 20 minutes neutral hypnosis including imaginative suggestions promoting relaxation.