The clinical effect of an implanted vagus nerve stimulator in a patient with chronic cluster headache and focal epilepsy: a case report

Abstract

Background: Treatment for chronic cluster headache (CCH) is often insufficient. Non-invasive vagus nerve stimulation (nVNS) was shown to be effective as acute treatment in episodic cluster headache (ECH) and open-label studies have shown a potential effect in CCH. The effect of invasive vagus nerve stimulation (iVNS) has not been formally studied in cluster headache (CH). Case Description: We report on a 71-year-old male with CCH and refractory epilepsy. His CH attacks present as extreme left-sided orbital pain with autonomic symptoms and fulfill the International Classification of Headache Disorder, third edition criteria. ECH started at the age of 8 years and progressed to CCH at the age of 10 years. Abortive treatment with sumatriptan or oxygen was effective, but prophylactic treatment was not tolerated or insufficient. Separately, he experienced episodic paroxysmal symptoms without pain, diagnosed as right frontotemporal focal epilepsy by ictal video-electroencephalogram recording. His seizures were refractory to treatment and a vagus nerve stimulator was implanted. Following surgery, both his seizures and CCH improved. Simultaneously with the titration of iVNS stimulation settings, his CH frequency decreased from 7 to 1 attack/week. Over 70 weeks post-implantation, this decrease in attack frequency persists. His only side-effect was hoarseness during the 7-s stimulation period of each duty cycle. Interestingly, CH frequency increased during a temporary iVNS deactivation for an unrelated procedure and decreased again once iVNS was reactivated. Case Description: We report on a 71-year-old male with CCH and refractory epilepsy. His CH attacks present as extreme left-sided orbital pain with autonomic symptoms and fulfill the International Classification of Headache Disorder, third edition criteria. ECH started at the age of 8 years and progressed to CCH at the age of 10 years. Abortive treatment with sumatriptan or oxygen was effective, but prophylactic treatment was not tolerated or insufficient. Separately, he experienced episodic paroxysmal symptoms without pain, diagnosed as right frontotemporal focal epilepsy by ictal video-electroencephalogram recording. His seizures were refractory to treatment and a vagus nerve stimulator was implanted. Following surgery, both his seizures and CCH improved. Simultaneously with the titration of iVNS stimulation settings, his CH frequency decreased from 7 to 1 attack/week. Over 70 weeks post-implantation, this decrease in attack frequency persists. His only side-effect was hoarseness during the 7-s stimulation period of each duty cycle. Interestingly, CH frequency increased during a temporary iVNS deactivation for an unrelated procedure and decreased again once iVNS was reactivated. Conclusion: In this case, iVNS was followed by >75% decrease in CH attack frequency. While natural disease course or placebo effect cannot be excluded, (i) the continued effect 70 weeks post-surgery, (ii) the dose-response effect with stimulation settings, and (iii) return of daily attacks during temporary iVNS deactivation suggest that iVNS could be responsible for the decreased attack frequency. As patients with CCH need more treatment options, further research into VNS as preventive treatment for CCH could be beneficial.