P05.17
Purpose: Insomnia comorbid with posttraumatic stress disorder (PTSD) is a prime example of dysfunction in the linkages between mind and body, thus serving as an ideal disease model to study the mind-body practice of yoga. The overall objective of this research is to evaluate feasibility of yoga as adjunctive treatment for insomnia related to posttraumatic stress disorder (PTSD). A sub-aim is to develop a novel method for evaluating complexity of heart rate variability in this population. A powerful way to assess the nonlinear behavior of a dynamical system, such as the autonomic nervous system (ANS), is represented by the Lyapunov exponents (LE). When evaluated on heart rate variability (HRV) time series, these nonlinear indices quantify how the cardiovascular control is sensitive to the ANS variations.
Methods: This study pertains a single-arm trial of an 8-week, closed-group yoga intervention for patients with insomnia and PTSD who are naive to yoga (<1 hour/week past 6 months). Continuous EKG data was collected at baseline and end treatment using a paced breathing protocol: 3 minutes regular breathing, 11 minutes audio-guided paced breathing at 15 cycles/minute, 3 minutes regular breathing. We estimated the instantaneous dominant LE (IDLE) through nonlinear point-process modeling of HRV data gathered from 12 study participants before and after yoga training.
Results: Between the two sessions, we found a significant decrease in the IDLE median absolute deviation (p<0.05), rather than in IDLE median value.
Conclusion: Previously we have shown that patients with severe cardiac health failure are characterized by a significant increase of complexity variability with respect to healthy subjects. The current results suggest that yoga affects ANS dynamics through shifts in sympathetic and parasympathetic activations which go towards a healthy ANS dynamical pattern and can be detected by the IDLE methodology.
Contact: Jessica Noggle Taylor, noggletaylor@research.bwh.harvard.edu
