Effects of the Timing of Vagus Nerve Stimulation Combined With Exercise in Chronic Neck Pain

N/ANot Yet RecruitingNCT07769034

Kutahya Health Sciences University81 enrolled

Overview

This randomized controlled trial aims to investigate whether the timing of transcutaneous auricular vagus nerve stimulation (taVNS) relative to exercise influences clinical and autonomic outcomes in individuals with chronic neck pain. Participants will be randomly allocated to one of three groups: taVNS applied before exercise, taVNS applied after exercise, or exercise alone. All groups will receive a standardized exercise program designed for chronic neck pain. The intervention will be conducted over a 6- to 8-week period. The effects of the interventions will be evaluated using pain intensity, neck-related disability, sleep quality, heart rate variability, and exercise adherence. The study will determine whether applying taVNS before or after exercise provides additional benefits compared with exercise alone and whether the timing of stimulation influences treatment outcomes.

Chronic neck pain is a common musculoskeletal condition associated with pain, functional limitations, sleep disturbances, and alterations in autonomic nervous system activity. Exercise therapy is one of the main conservative treatment approaches for chronic neck pain. Transcutaneous auricular vagus nerve stimulation (taVNS) is a non-invasive neuromodulation method that aims to stimulate the auricular branch of the vagus nerve and may influence parasympathetic activity and pain modulation. The purpose of this randomized controlled trial is to investigate whether the timing of taVNS relative to exercise influences clinical and physiological outcomes in individuals with chronic neck pain. A total of 81 participants with chronic neck pain will be randomly allocated to three parallel groups. Participants in the first group will receive taVNS before performing a standardized exercise program. Participants in the second group will perform the same exercise program followed by taVNS. Participants in the control group will receive the exercise program alone. The exercise program will include postural correction exercises, deep cervical flexor activation exercises, cervical mobility exercises, scapular stabilization exercises, and stretching exercises. The intervention period will last approximately 6-8 weeks. Participants will be evaluated before and after the intervention period. Pain intensity will be assessed using the Numeric Pain Rating Scale, neck-related disability using the Neck Disability Index, sleep quality using the Pittsburgh Sleep Quality Index, and autonomic nervous system activity using heart rate variability, particularly the root mean square of successive differences (RMSSD). Exercise adherence and session attendance will also be recorded. The study will compare changes in these outcomes among the three groups to determine whether the timing of taVNS relative to exercise influences the effectiveness of rehabilitation in individuals with chronic neck pain.

Interventions

Transcutaneous Auricular Vagus Nerve Stimulation (taVNS)DEVICE

Transcutaneous auricular vagus nerve stimulation will be delivered non-invasively through an auricular stimulation device targeting the auricular branch of the vagus nerve. Stimulation will be administered under researcher supervision using standardized stimulation parameters according to the device instructions and study protocol.

Exercise ProgramOTHER

Participants will perform a standardized exercise program for chronic neck pain including postural correction, deep cervical flexor activation, cervical mobility, scapular stabilization, and stretching exercises. Exercises will be performed under researcher supervision during the intervention period.

Eligibility

Sex: ALLMin age: 18 YearsMax age: 65 Years

Medical Language ↔ Plain English

Inclusion Criteria: * Diagnosis of chronic neck pain confirmed by a physical medicine and rehabilitation physician. * Age between 18 and 65 years. * Neck pain persisting or recurring for at least 3 months. * Ability to participate in the exercise program included in the study protocol. * No contraindication to transcutaneous auricular vagus nerve stimulation. * Willingness to provide written informed consent. * Willingness to participate regularly in the planned exercise and assessment sessions. Exclusion Criteria: * Cervical radiculopathy or specific neurological findings. * Previous cervical spine surgery. * Serious cardiovascular disease. * Serious neurological or systemic disease. * Pregnancy. * Orthopedic or musculoskeletal conditions preventing participation in exercise. * Cognitive or communication problems that prevent completion of the assessment instruments. * Inability or unwillingness to comply with the study protocol or attend scheduled sessions.

Outcomes

Primary Outcomes

Change in Pain Intensity - Numeric Pain Rating Scale

Pain intensity will be assessed using the Numeric Pain Rating Scale (NPRS). Participants will rate their neck pain on an 11-point scale ranging from 0 to 10, where 0 indicates "no pain" and 10 indicates "worst imaginable pain." Higher scores indicate greater pain intensity. Change from baseline will be compared between groups.

Time frame: Baseline and immediately after completion of the 6 week interventions

Change in Neck-Related Disability - Neck Disability Index

Neck-related disability will be assessed using the Neck Disability Index (NDI). The questionnaire consists of 10 sections scored from 0 to 5, producing a total score ranging from 0 to 50. Higher scores indicate greater neck-related disability.

Time frame: Baseline and immediately after completion of the 6 weeks interventions.

Change in Sleep Quality - Pittsburgh Sleep Quality Index

Sleep quality will be assessed using the Pittsburgh Sleep Quality Index (PSQI). The PSQI evaluates seven components of sleep and provides a global score ranging from 0 to 21. Higher scores indicate poorer sleep quality.

Time frame: Baseline and immediately after completion of the 6 weeks intervention.

Secondary Outcomes

Exercise Adherence

Exercise adherence will be assessed based on participant attendance at scheduled treatment sessions. Adherence will be expressed as the number and/or percentage of completed sessions relative to the total number of planned sessions.

Time frame: Throughout the 6-8-week intervention period.

Change in Heart Rate Variability - RMSSD

Autonomic nervous system activity will be assessed using heart rate variability. The root mean square of successive differences between normal heartbeats (RMSSD), expressed in milliseconds, will be used as the primary heart rate variability parameter. Higher RMSSD values generally represent greater parasympathetic/vagal activity.