The effects of muscle biofeedback versus posture biofeedback on pain and functional outcome in smartphone users with chronic neck pain

Background : Smartphones have become an essential part of our daily lives, and prolonged use in static neck flexion posture could contribute to chronic neck pain. Objectives: This study compared the effects of two different forms of biofeedback on neck pain, habitual posture adoption and muscle activity during smartphone texting. Methods: This was a randomised controlled trial with 3 groups. Group 1 involved muscle biofeedback and Group 2 postural biofeedback. Each participant used the biofeedback device for 2 hours daily for 6 weeks. Control group performed stretching exercises at home for 6 weeks. Outcome measures included neck pain score (0-10) and Neck Disability Index (NDI) scores. Muscle activity and neck postural angle during smartphone texting task were also evaluated during pre- and post-intervention. Results: Both the postural biofeedback and muscle biofeedback groups showed significant reduction in pain and NDI scores in pre-post intervention comparisons (p<0.05), but not in control group. In smartphone texting task, bilateral cervical erector spinae muscle activity and average neck flexion angle showed a trend for greater reduction in Group 1 compared to Group 2. Control group showed no change at all in muscle activity and neck postural angle. Conclusion: This trial demonstrated the effectiveness of both postural and muscle biofeedback training producing significant reduction in neck pain and comparable extent of change in neck flexion posture and muscle activity during smartphone texting. These results suggest that biofeedback with either device can be a useful tool for self-management of neck pain related to intensive smartphone use.