Effects of vagal nerve stimulation on pain frequency and intensity in chronic migraine in adults: A randomized controlled trial

To determine the effects of noninvasive vagal nerve stimulation (nVNS) on the frequency, intensity, impact, and quality of life in individuals with chronic migraine. The randomized controlled trial (RCT) was conducted over 128 participants, randomly assigned to either the experimental or control group. The experimental group received nVNS, while the control group underwent sham interventions along with the prescribed medications. Data collection involved the pre and post-use of a structured headache diary, a numerical pain scale (NPS), the multidimensional pain inventory, and migraine-specific quality of life (MS-QoL) questionnaires. The experimental group's MS-QoL scores significantly improved, with a mean rank of 94.59, and p value <0.001. Similarly, the NPS scores showed that the experimental group's pain levels were considerably lower, with a mean rank of 36.77 and p value <0.001. The MPI scores highlighted a substantial reduction in pain-related interference and behaviors within the experimental group, with p value = 0.035. In terms of headache severity, the structured headache diary revealed that the experimental group experienced fewer severe headaches, with only 16 instances (15.6%), and an increase in moderate headaches to 51 instances (51.6%). The study indicates that nVNS significantly enhanced quality of life and reduced pain intensity, frequency, and impact among chronic migraine patients over 4 weeks of active stimulation.