Background: The debilitating nature of migraine and challenges associated with treatment-refractory migraine have a profound impact on patients. With the need for alternatives to pharmacologic agents, vagus nerve stimulation has demonstrated efficacy in treatment-refractory primary headache disorders. We investigated the use of cervical non-invasive vagus nerve stimulation (nVNS) for the acute treatment and prevention of migraine attacks in treatment-refractory episodic and chronic migraine (EM and CM) and evaluated the impact of nVNS on migraine-associated sleep disturbance, disability, and depressive symptoms.
Methods: Twenty patients with treatment-refractory migraine were enrolled in this 3-month, open-label, prospective observational study. Patients administered nVNS prophylactically twice daily at prespecified times and acutely as adjunctive therapy for migraine attacks. Pain intensity (visual analogue scale [VAS]); number of headache days per month and number of migraine attacks per month; number of acutely treated attacks and time to achieve pain relief; sleep quality (Pittsburgh Sleep Quality Index [PSQI]); migraine disability assessment (MIDAS); depressive symptoms (Beck Depression Inventory(®) [BDI]); and adverse events (AEs) were evaluated.
Results: Of the 20 enrolled patients, 10 patients each had been diagnosed with EM and CM. Prophylaxis with nVNS was associated with significant overall reductions in patient-perceived pain intensity (mean VAS scores at baseline vs 3 months: 7.75 ± 0.64 vs 4.05 ± 0.76; 95 % CI: 3.3, 4.1; p < 0.0001), mean number of headache days per month (baseline vs 3 months: 14.7 ± 4.1 vs 8.9 ± 3.66; 95 % CI: 3.3, 8.3; p < 0.0001), and mean number of migraine attacks per month (baseline vs 3 months: 7.3 ± 3.85 vs 4.45 ± 2.48; 95 % CI: 0.8, 4.9; p < 0.01). For acutely treated migraine attacks, a reduction in mean time (minutes) to achieve pain relief (baseline vs 3 months: 84.5 ± 39.1 vs 52.75 ± 16.42; 95 % CI: 12.6, 51.0; p < 0.002) was noted. Significant improvements, more evident in patients with EM, were noted in MIDAS and BDI scores along with a trend toward improvement in PSQI daytime dysfunction subscore (p = 0.07). No severe or serious AEs occurred.
Conclusion: In this study, treatment with nVNS was safe and provided clinically meaningful decreases in the frequency, intensity, and duration of migraine attacks in patients with treatment-refractory migraine. Improvements in migraine-associated disability, depression, and sleep quality were also noted.
Keywords: Acute therapy; Headache; Neuromodulation; Prophylactic therapy; Sleep impairment.