The study is a prospective randomized controlled multi-center investigation designed for comparison of two parallel groups, GammaCore® (active treatment) and Standard of Care, SoC, (control). The study period begins with a 2 week run-in period, followed by a 4 week comparative period when the subjects are randomized to either active treatment or control 1:1. The comparative period will be followed by a period where all subject will receive GammaCore® for 4 weeks.After the subject signed the Consent Form for participation the baseline (visit1) data will be collected. Subject will be informed how to complete the 2 week diary during the run-in period During the run-in period, all subjects will use stable SoC according to their individual prescriptions. The subject will record as CH attack regarding duration and frequency and the use of medication and oxygen.