Initial research into VNS was inspired by the writings of Corning, a New York neurologist, who as far back as 1882 suggested that electrical stimulation of the vagus nerve might provide the same benefit he had discovered from carotid massage for the management of epilepsy.
This suggestion – based on a false assumption that modulation of blood flow was the source of the clinical benefit – was intermittently studied until 1952, when Dr Alberto Zanchetti, an Italian cardiologist, demonstrated that VNS was affecting the electrical currents in the nerves, not the vascular system.
In 1997 Cyberonics received the first FDA approval for a surgically implanted vagus nerve stimulator for the treatment of refractory epilepsy. While efficacy and safety were shown in these studies, the underlying mechanism of action was still not fully explained.
Recipients of implanted VNS devices began reporting additional clinical benefits including reduction in depression symptoms and in 2005, Cyberonics was able to secure FDA approval for the treatment of refractory depression.
In the last sixteen years more than 100,000 patients have undergone the VNS surgical procedure with minimal side effects.
However, the high cost and invasiveness of surgically implanted pacemaker-like devices have relegated surgical VNS therapy to the end of the continuum of care.
In this century, further research into VNS stimulation identified that stimulating particular afferent fibers (these are the fibers which travel to the brain, the efferent fibers travel from the brain) in the vagus nerve causes the release of inhibitory neurotransmitters including GABA, serotonin and norepinephirine within the central nervous system. These neurotransmitters are known to play a pivotal role in a wide range of conditions.
In 2010, electroCore developed a breakthrough VNS therapy –nVNS- which non invasively stimulates the afferent fibers of the vagus nerve. The therapy is delivered through electroCore’s gammaCore device which is placed on the neck over the vagus nerve.
electroCore’s nVNS delivery technology has shifted the paradigm, by permitting patients to self-administer discrete doses of gammaCore therapy for acute and prophylactic benefit at a very competitive cost.