Effects of Autonomic Nervous System Modulation on Heart Rate Variability and Musculoskeletal Manifestations in Patients With Chronic Neck Pain

Background: Chronic neck pain is a widespread musculoskeletal disorder. Studies investigating the effect of autonomic nervous system (ANS) modulation in chronic neck pain are scarce. This study aims to examine the effects of ANS modulation on heart rate variability, pain, and function in patients with chronic neck pain. Methods: The intended study is a double-blind, randomized controlled trial in a parallel three arms fashion. Hundred and two patients with chronic neck pain will be recruited from King Fahd Hospital of the University in Alkhobar, Saudi Arabia. The patients will be randomly allocated equally into one of three groups. Group A (n = 34) will receive transcutaneous vagus nerve stimulation (tVNS) and standard-care physiotherapy (SC-PT). Group B (n = 34) will receive heart rate variability biofeedback (HRV-BF) and SC-PT. Group C (n = 34) will receive SC-PT alone. Each group will receive the intervention three times per week for six weeks. The primary outcome measures are HRV to assess ANS and the visual analog scale for pain intensity. The secondary outcome measures are pressure pain threshold and neck disability index. All these measures will be assessed on three occasions; at baseline, after three weeks, and after six weeks from baseline. For the statistical analysis, normality of the data will be performed prior to the analyses and suitable statistical tests will be applied to examine the effect of the interventions between the groups. The significance level sets at P \< 0.05.