The effect of auricular vagus nerve stimulation in women with temporomandibular joint disorders: a randomized controlled study

Temporomandibular disorders associated with myofascial pain syndrome cause pain and disability in daily life. The aim of this study was to investigate the effect of auricular vagus nerve stimulation on pain in women with myofascial pain syndrome-related temporomandibular disorder. A total of 50 women with myofascial pain syndrome-related temporomandibular disorder aged between 18 and 35 years participated in this study. The vagus group (n=25) received auricular vagus nerve stimulation and manual therapy and exercise, and the control group (n=25) received only manual therapy and exercise twice a week for 3 months. The pressure pain threshold was used for the assessment. In the vagus group, pressure pain threshold on the masseter, temporalis, sternocleidomastoid, digastricus, trapezius, and levator scapula muscles increased statistically significantly after treatment compared to baseline (p<0.05). In the control group, pressure pain threshold on the masseter and levator scapula muscles increased (p<0.05), while no statistically significant difference was found in the pressure pain threshold on the temporalis, sternocleidomastoid, digastricus, and trapezius muscles (p>0.05). When both groups were compared, vagus group was found to be more effective than control group in increasing pressure pain threshold in the masseter, trapezius, and levator scapula muscles (p<0.05). Auricular vagus nerve stimulation was found to be effective in increasing pressure pain threshold in patients with myofascial pain syndrome-related temporomandibular disorder. The clinical trial registration number was NCT05500716.