The effect of application of vagus nerve stimulation on the treatment efficiency in temporomandibular joint dysfunction caused by myofascial pain syndrome

Conducting studies trying to reveal the relationship between temporomandibular joint dysfunction and autonomic nervous system disorders has highlighted the option of transcutaneous vagus nerve stimulation as a treatment option. The aim of this study is to evaluate the autonomic nervous system in patients with temporomandibular joint dysfunction due to myofascial pain syndrome and to increase parasympathetic nervous system activity by applying transcutaneous vagus nerve stimulation. Fifty patients between the ages of 18-35 who experienced temporomandibular joint dysfunction due to myofascial pain syndrome were included in the study. In the evaluation of the patients, measurement methods of rest and activity pain, joint range of motion, pressure pain threshold, heart rate variability, perceived stress scale, kinesiophobia scale and Neck Disability Questionnaire were used. In intragroup comparisons, a significant reduction in resting and activity pain was observed in both the rehabilitation group and the vagus stimulation group (p<0.05). When both groups were compared, no significant difference was found in resting and activity pain (p>0.05). When joint range of motion was compared in both groups, no significant difference was found between the two groups (p>0.05). When the pressure pain threshold was compared between the two groups, it was observed that vagus stimulation application in addition to rehabilitation was more effective in increasing the pressure pain threshold in the masseter, trapezius and levator scapula muscles (p<0.05). When heart rate variability measurement results were compared within the group, no significant difference was observed in the rehabilitation group (p>0.05), while a significant difference was found in the stress index, SNS index, PNS index, RMSSD, LF and HF parameters in the vagus group (p<0.05). When both groups were compared, a statistically significant difference was found in the SNS index and PNS indices in the vagus group (p<0.05). In conclusion, it may be beneficial to include vagus nerve stimulation in the rehabilitation program in temporomandibular disorders.