A Randomized, Sham-controlled Study of gammaCore ® (nVNS) for Prevention of Episodic Migraine

The study period will begin with a four week run-in period, during which there is no investigational treatment. The purpose of the run-in period will be observation for baseline comparison. The run-in period will be, followed by a 12 week randomized period when the subjects will be randomized (1:1) to either active treatment or sham (inactive) treatment. The randomized period will be followed by a 24 week open label period, where the subjects in the sham treatment group will switch in treatment assignment and receive a gammaCore®-R and the gammaCore®-R will continue to receive an active treatment.