Chronic Ischemic stroke occurs when blood supply to the brain gets cut off for a long time. The resulting cell damage causes varying symptoms depending on the area of the brain that got affected. This includes confusion, blindness, vertigo, or even weakness and paralysis of the limbs.
The usual treatment for such motor deficiencies of the limbs is rehabilitative exercise. However, the FDA has now approved an implantable Vagus nerve stimulating device called the Vivistim Paired VNS System created by the company MicroTransponder, which, when used in conjunction with physical therapy demonstrates better muscular rehabilitation in patients who have suffered from an ischemic stroke.
According to Christopher M. Loftus, M.D., who is the acting director of the FDA’s Center for Devices and Radiological Health’s Office of Neurological and Physical Medicine Devices:
“People who have lost mobility in their hands and arms due to ischemic stroke are often limited in their treatment options for regaining motor function. Today’s approval of the Vivistim Paired VNS System offers the first stroke rehabilitation option using Vagus nerve stimulation. Used alongside rehabilitative exercise, this device may offer benefit to those who have lost function in their upper limbs due to ischemic stroke.”
The Vivistim System
The Vivistim System is a prescription Implantable Pulse Generator (IPG) that doctors place in a patient’s chest, beneath their skin. It is accompanied by electrodes on a lead wire that are placed above the Vagus nerve in the neck.
Once placed, the patient’s healthcare provider sets up the IPG using laptop software and a wireless transmitter. The IPG then generates electrical pulses to stimulate the Vagus nerve. This is usually done while the patient is undergoing physical therapy, with the aim of improving their muscular function. Patients can also use the system at home using a magnet that switches the IPG on. However, safety precautions entail that they cannot use the software and transmitter to control the settings on their own.
The FDA trial
The FDA approved the System after completing a clinical trial that enrolled 108 patients from the UK and the US. They divided the patients into a control group of 55 ( who received a low level of VNS) and a study group of 53 (who received the prescribed amount). All participants were required to undergo 90-minute physical therapy sessions, 3 days a week for six weeks.
At the end of the trial, the researchers saw that the motor function in the study group had increased by almost double as compared to the control group.
As a result of the successful trial, the FDA designated the Vivistim System a “Breakthrough Device”.