International Journal of Clinical and Health Psychology, 2006, 6, 549-563. Changes in heart rate variability of flight phobics during a paced breathing task and exposure to fearful stimuli. Xavier Bornas, Jordi Llabrés, Miquel Noguera, Ana María López, Miquel Tortella-Feliu, Miquel Ángel Fullana, Pedro Montoya, Joan Miquel Gelabert, and Irene Vila
The aim of this experiment was to explore changes in the vagally mediated heart rate variability (HRV) of flight phobics during exposure to feared stimuli. A paced breathing task was included to control for respiration effects. Sixty-one flight phobics (40 women) with a mean age of 39.07 years (SD = 11.24) participated in the study. The root mean of the squared successive interbeat intervals differences (RMSSD) was taken as the time domain measure of HRV. High frequency (HF: 0.15-0.4 Hz) and low frequency (LF: 0.04-0.15 Hz) band power was calculated on the ECG recordings obtained during free breathing baseline (BL), paced breathing (PB), and exposure (E) to fearful stimuli. Heart rate unexpectedly increased from BL to PB, and decreased from PB to E, while no differences were found between BL and E. No changes in the RMSSD were seen across conditions. HF band power increased, as expected, from BL to PB, and a significant decrease was found from PB to E. LF band power, as well as the LF/HF ratio, increased from BL to E. Discussion focuses on (a) the role of the parasympathetic and the sympathetic nervous systems in fear-related situations, and (b) the effects of paced breathing in preparing the system to cope with threat.
Psychotherapy Research. Volume 16, Issue 1, 2006, 41-50. Do all treatments work for flight phobia? Computer-assisted exposure versus a brief multicomponent nonexposure treatment. DOI:10.1080/10503300500091058. Xavier Bornas, Miquel Tortella-Feliu & Jordi Llabrés
Computer-assisted treatments have proven to be effective in the treatment of several anxiety disorders and depression, but the role of exposure remains unclear. This study compares the efficacy of a computer-assisted exposure treatment (CAE) with a brief multicomponent nonexposure treatment (MNE) for flight phobia. Outcome measure assessments were conducted at posttreatment and at 6-month follow-up. No differences were found between CAE and MNE in reducing fear of flying. In both conditions patients improved significantly and clinically meaningfully, and results were maintained at 6- month follow-up. These findings challenge the idea that exposure is essential in reducing phobic anxiety and support the idea that specific phobias may be well suited for brief cognitive–behavioral treatments.
Nonlinear Dynamics Psychol Life Sci. 2006 Jul;10(3):301-18. Sample entropy of ECG time series of fearful flyers: preliminary results. Bornas X, Llabrés J, Noguera M, Pérez A.
Research within the framework of the nonlinear dynamical systems (NDS) in the field of anxiety disorders has shown that greater irregularity/complexity appears in the output from healthy systems. In this study we measured the Heart rate variability (HRV) and the sample sntropy (SampEn) of the ECG mV time series of fearful flyers (N = 15) and a matched control group (N = 15) when confronted with three combinations of feared stimuli (pictures, sounds, and pictures with sounds) as well as relaxing stimuli (pictures and sounds). Fearful flyers had lower SampEn than controls in all conditions, including baseline. Non-phobics showed significant entropy decreases from baseline in two out of three exposure conditions. No differences on HRV were found between groups, and HRV was not sensitive to condition changes. The main finding of the study is that the SampEn calculated on very short ECG mV recordings (10 to 60 seconds, easy to obtain in clinical settings) may be a useful diagnostic measure since it can distinguish fearful from non-fearful flyers.
Xavier Bornas, Jordi Llabres, Miquel Noguera, Ana M Lopez, Joan Miquel Gelabert, Irene Vila, Fear induced complexity loss in the electrocardiogram of flight phobics: A multiscale entropy analysis, Biological Psychology, Volume 73, Issue 3, October 2006, Pages 272-279, ISSN 0301-0511, DOI: 10.1016/j.biopsycho.2006.05.004.
In this study we explored the changes in the variability and complexity of the electrocardiogram (ECG) of flight phobics (N = 61) and a matched non-phobic control group (N = 58) when they performed a paced breathing task and were exposed to flight related stimuli. Lower complexity/entropy values were expected in phobics as compared to controls. The phobic system complexity as well as the heart rate variability (HRV) were expected to be reduced by the exposure to fearful stimuli. The multiscale entropy (MSE) analysis revealed lower entropy values in phobics during paced breathing and exposure, and a complexity loss was observed in phobics during exposure to threatening situations. The expected HRV decreases were not found in this study. The discussion is focused on the distinction between variability and complexity measures of the cardiac output, and on the usefulness of the MSE analysis in the field of anxiety disorders.