 One such option is a treatment called vagus nerve stimulation VNS, in which short bursts of electrical energy are directed into the brain by way of the vagus nerve. The vagus nerve is a cranial nerve that originates in the brainstem, travels through the neck, and then continues down through the thorax and abdomen. The nerve acts as both a sensory and motor nerve, and it can regulate several brain areas involved in pain and emotional processing. With VNS, a small battery device is surgically implanted under the skin, usually under the chest, and provides the necessary electrical energy for stimulation. Although VNS has been FDA approved for some forms of epilepsy and depression, it has yet to receive FDA approval for FMS. Also, it is unknown whether the safety and tolerability profile of an FMS patient receiving VNS is the same as that of a patient with epilepsy or depression who is receiving VNS. The purpose of this study is to determine the safety, tolerability, and effectiveness of VNS as a treatment option for adults with refractory FMS. 