Cardiac Autonomic Regulation under Hypnosis Assessed by Heart Rate Variability: Spectral Analysis and Fractal Complexity

Abstract

Objective: This study examined the effects of hypnosis on autonomic cardiac control. We hypothesized a modification of autonomic modulation of the heart rate with an enhanced vagal tone during hypnosis compared to baseline. Methods: In 12 healthy subjects (6 men and 6 women, 22.2 ± 1.0 years of age) ECG was recorded at baseline and during hypnosis. Heart rate variability parameters were obtained in the frequency domain (LFnu: low frequency normalized units, and HFnu: high frequency normalized units) and from nonlinear analysis methods (detrended fluctuation analysis, DFA). Results: Compared to the control condition, hypnosis showed a significantly decreased LFnu, a significantly increased HFnu, and a significantly decreased LF/HF. DFA showed a significantly decreased short-range similarity. Heart rate remained unchanged. Conclusion: Autonomic cardiac tone is significantly modified during hypnosis by shifting the balance of the sympathovagal interaction toward an enhanced parasympathetic modulation, accompanied by a reduction of the sympathetic tone and a decreased short-range similarity but without a concomitant change in heart rate. Central and secondary autonomous nervous system changes induced by hypnosis are a possible explanation for our results. Another highly probable explanation is given by a variation in the depth of respiration. Hypnosis appears to prevent the autonomic responses expected during neutral stimulation.

Brain correlates of hypnotic paralysis—a resting-state fMRI study

“…Furthermore, respiration and cardiac rhythm were not measured during fMRI data acquisition and therefore cannot be excluded as confounding factor in the data analysis. The influence of hypnosis on heart rate is still controversially discussed (Aubert et al, 2009;Emdin et al, 1996;Santarcangelo et al, 2008;VandeVusse et al, 2010). However, heart rate affects widely distributed areas of the brain (Birn et al, 2006;Shmueli et al, 2007) while effects observed here were rather circumscribed.…”

Alterations in electrodermal activity and cardiac parasympathetic tone during hypnosis

“…This finding, however, was not unequivocally supported (De Pascalis & Perrone, ; Gemignani et al, ; Hippel, Hole, & Kaschka, ; Ray et al, ). The conclusions of previous studies for the influence of hypnosis on the sympathetic nervous system (SNS) activity are similarly mixed with some studies showing decreased activity during hypnosis (Aubert et al, ; De Pascalis & Perrone, ; Debenedittis et al, ; Griffiths, Gillett, & Davies, ; Gruzelier, Brow, Perry, Rhonder, & Thomas, ; Gruzelier & Brow, ; Hippel et al, ) and studies that did not find decreased SNS activity (M. J. Diamond, ; Edmonston, ; Gruzelier, Allison, & Conway, ).…”

“…A number of studies and a recent review argue that hypnosis enhances parasympathetic nervous system (PNS) activity (Aubert, Verheyden, Beckers, Tack, & Vandenberghe, ; Debenedittis, Cigada, Bianchi, Signorini, & Cerutti, ; S. G. Diamond, Davis, & Howe, ; van der Kruijs et al, ; VandeVusse, Hanson, Berner, & White Winters, ), which would indicate a relaxationlike effect (Sakakibara, Takeuchi, & Hayano, ). This finding, however, was not unequivocally supported (De Pascalis & Perrone, ; Gemignani et al, ; Hippel, Hole, & Kaschka, ; Ray et al, ).…”

The effect of sedation during transoesophageal echocardiography on heart rate variability: a comparison of hypnotic sedation with medical sedation

“…LF/HF rate was significantly lower in the hypnosis group compared to other two groups. In their study, Aubert et al [18] found that in healthy individuals LF levels were decreased in the hypnosis group while HF was increased and LF/HF rate was decreased. DeBenedittis et al [19] found similar results in healthy individuals undergoing hypnosis.…”