UT Southwestern Medical Center and two other U.S. sites will test a new implanted device called Vivistim System that can stimulate the vagus nerve in patients with stroke, hopefully helping repair lost arm function.
Dallas-based MicroTransponder Inc., developed and licensed the device, which stimulates the neck’s vagus nerve. The device is implanted under the collarbone, is the size of a pacemaker and sends half-second electrical pulses up the vagus nerve, causing neuromodulators to be released into the brain. The FDA has already approved other forms of stimulation of the vagus nerve as treatment for other conditions such as epilepsy and depression.
“These neuromodulators appear to facilitate the creation of new neuron pathways in the brain, which play a key role in restoring muscle movement,” said in a recent news release Dr. Ty Shang, Assistant Professor of Neurology and Neurotherapeutics at UT Southwestern, who is heading the UT Southwestern arm of the trial.
“A stroke deprives brain cells of oxygen,” said Dr. Shang, a vascular neurologist who is part of UT Southwestern’s stroke team. “Without oxygen, the brain cells die, and can no longer perform the function for which they were intended. There has been no known way to regenerate new brain cells to replace them, but in early tests with this device, the brain appears to ‘rewire’ other cells to perform the function”.
MicroTransponder Inc. and the Texas Biomedical Device Center at UT Dallas are sponsoring the study of Vivistim system, which is designed for motor function improvement in the most affected arm of a person following stroke. The study of the device’s safety and efficacy started in Glasgow, Scotland in 2013 in a small trial with patients that had functional improvements in their more involved arm.
“VNS therapy may be the stimulus for motor relearning with the more involved arm for individuals following stroke. Gaining functional improvement in the impaired arm is an arduous task. VNS therapy might make achieving functional gains easier,” Dr. Shang said in the news release.
The researchers at UT Southwestern are now looking for patients who had a stroke four months to five years ago in the Dallas-Fort Worth metroplex. Participants will be implanted with the device and after will receive 18 session of 90 minutes of intensive, task-specific therapy over a period of six weeks with four follow-ups for one year.
Stroke occurs due to an interruption on the brain blood supply. In the United States, nearly one in every six persons have a stroke usually after the age of 65 years. Stroke is only fatal in about 10 to 20% of the cases, however, it can lead to loss of mobility functions such as, impaired speech, cognitive problems, and loss of arm or leg function. According to the National Institute of Neurological Disorders and Stroke, the condition is a leading cause of adult disability in the U.S.
The UT Southwestern’s Neurology Clinic is a US stroke-leading clinic. The Joint Commission and the American Heart Association(AHA)/American Stroke Association (ASA) recently certified the UT Southwestern University Hospitals as an Advanced Comprehensive Stroke Center. The cerebrovascular program at UT Southwestern involves a multidisciplinary team with top-expertise to treat all forms of brain stroke and blood-vessel disease.