Monitoring change in heart rate variability following acceptance and commitment therapy for chronic pain: Results of a randomized controlled trial for individuals with neurofibromatosis type 1

Acceptance and Commitment Therapy (ACT) is a well-evidenced therapeutic model for the treatment of chronic pain. While there is substantial data that indicates improvement in the cognitive and behavioral aspects of pain (e.g., pain acceptance, pain inflexibility, pain interference), significantly less research has explored changes in physiological variables following acceptance-based interventions. In particular, heart rate variability (HRV) is a physiological marker of pain and reflects the time elapsed between heart beats. The current study examined whether HRV changed following a randomized-controlled trial of ACT for individuals with neurofibromatosis type 1 and chronic pain (N = 62). Repeated measures analyses of covariance assessed change following ACT. In addition, hierarchical linear regression models examined pain-related predictors of HRV at follow-up. The results suggest that HRV improves following ACT, although given the small sample and limited analytical model, the findings should be considered preliminary. Further, improvements in HRV over the course of the intervention predicted improvements in pain intensity at follow-up suggesting a relationship between these two variables. Taken together, these data provide modest evidence of the relationships between ACT and HRV within a chronic pain population. Additional implications and future directions are discussed.