04 Mar Vagus Nerve Stimulation Suppresses Brain Activity that Leads to Aura, Headache
A new animal study suggests that electrically stimulating the vagus nerve suppresses activity in the brain believed to be a headache trigger and responsible for migraine-related auras.
Scientists at Massachusetts General Hospital and Harvard Medical School found that in rats, vagus nerve stimulation (VNS) tripled the resistance to both electrically- and chemically-triggered corticol spreading depression (CSD). In CSD, corticol neurons go silent in a wave-like action in the brain. Moreover, the researchers found that VNS achieved effectiveness within 30 minutes of the administration of therapy, significantly better than the results of prophylactic migraine medications, which can take weeks to achieve similar results.
Additionally, the study showed that non-invasive vagus nerve stimulation (nVNS) was as effective as surgically implanted vagus nerve stimulation (iVNS) in reducing CSDs by up to 40%. The non-invasive VNS treatment, which involves the delivery of two 2-minute doses, suppressed CSDs during the 3-hour study, with no indication that the efficacy had diminished.
Researchers also found that stimulating the vagus nerve on only one side of the neck suppressed CSDs triggered on both sides of the brain. They indicated that nVNS may be useful in treating unilateral or bilateral headaches, regardless of which side is stimulated.
Cenk Ayata, MD, the senior author, commented on the success of the study, which appeared recently in the journal Pain.
“We have established that VNS reduces cerebral excitability as shown by CSD suppression, and that VNS has a strikingly rapid onset of action compared to traditional migraine prophylactic agents, such as topiramate and valproate. We also established that both the non-invasive hand-held gammaCore device and the surgically implanted device should be equally effective in reducing cortical spreading depression,” he said.
The authors concluded that their findings show promise for vagus nerve stimulation and migraine treatment.