Noninvasive nerve stimulation may limit stroke damage

Delivering electrical stimulation to the brain by non-invasively stimulating the vagus nerve through the skin provided significant protection from brain damage following a clot-induced stroke in rats, according to a study presented by Martinos Center researchers last month at the American Stroke Association’s International Stroke Conference 2014.

The vagus nerve is the longest cranial nerve. It contains motor and sensory fibers and, because it passes through the neck and thorax to the abdomen, has the widest distribution in the body.

Stimulating the vagus nerve through an implanted electrode can reduce the size of clot-induced strokes in rats, but the surgery-requiring approach is impractical for rapidly treating stroke in humans.

The researchers found that one hour of stimulation of the vagus nerve using surface electrodes applied to the external ear or the neck skin overlying the vagus nerve, beginning 30 minutes after the stroke was induced, led to a smaller area of brain tissue damage, better grip strength and improved scores on neurological tests for the rats.

"These findings have the potential to facilitate the development of novel treatment paradigms based on neurostimulation for acute ischemic stroke," said the Martinos Center's Ilknur Ay, who presented the study. "If proven safe and effective, such methods could avoid missed opportunities to reduce ischemic brain injury as they can be easily applied as an adjunctive treatment even in the ambulance."

The researchers continue to develop the approach. They are now working to establish the therapeutic time window and to determine the safety and efficacy of combined vagus nerve stimulation and recombinant tissue plasminogen activator (rtPA) treatment, Ay said. rtPA is the only FDA-approved treatment in acute stroke.

(via the American Heart Association newsroom)