A Randomized Multicentre Study for the Acute Relief of Episodic and Chronic Cluster Headache.

Inclusion Criteria: * Is 18 years or older * Has been diagnosed with episodic or chronic cluster headache in accordance with the ICHD-2 Classification criteria (2ndEd) * Is capable of completing the 5-point pain scale, disability scale and other self-assessments * Agrees to refrain from starting new medication aimed to control the cluster headache for the duration of the run-in and randomized phase * Is able to provide written Informed Consent Exclusion Criteria:1. * Episodic cluster headache sufferers who are not in a cluster headache bout at the time of screening and enrollment * 2\. Need to commence treatment with oral or injectable steroids for eventual concomitant medical conditions * 3\. Has a lesion (including lymphadenopathy), dysaesthesia, previous surgery or abnormal anatomy at the GammaCore® treatment site * 4\. Is currently taking medication for indications other than CH that in the opinion of the clinician may interfere with the study * 5\. Has a history of any cranial aneurysm, intracranial haemorrhage, brain tumours or significant head trauma * 6\. Diagnosed or suspected secondary headache * 7\. Has other significant pain problem that might confound the study assessments in the opinion of the investigator * 8\. Has known or suspected severe atherosclerotic cardiovascular disease, severe carotid artery disease (e.g. bruits or history of transient ischemic attack (TIA) or cerebral vascular accident CVA), congestive heart failure (CHF), known severe coronary ar…