The therapy involves nerve stimulation to improve recovery.
Stroke rehab therapy has remained much the same for decades. But now a new type of therapy that involves nerve stimulation has shown promising results in dramatically increasing recovery time for some patients.
Often, after surviving a stroke, many people have trouble using the hand or arm on the affected side of their body.
To help them regain use of their limb, healthcare providers typically recommend rehabilitation therapy. This includes physical therapy, where patients complete repetitive tasks to help improve the function of their impaired limb.
The researchers behind the study believe that VNS might provide an “extra boost” to the neurons responsible for controlling movement in a patient’s hand or arm.
“The theory is that the vagus nerve, when it’s stimulated, releases neurotransmitters into the brain,” Teresa Kimberley, PhD, lead author and director of the Brain Recovery Lab at the Massachusetts General Hospital Institute of Health Professions, told Healthline.
“So if you’re trying to open your hand,” she continued, “all the neurons in your brain that are associated with hand-opening are trying to work, and those neurons have extra neurotransmitters available to help strengthen that synaptic connection.”
The pilot study was a phase II clinical trial that involved 17 participants, all of whom had experienced a stroke 4 months to 5 years before they were enrolled.
At the outset of the study, eight of the participants were implanted with an active VNS device that delivered electrical stimuli to their vagus nerve. The remaining nine participants were implanted with an inactive device.
Over a period of six weeks, all of the participants attended multiple sessions of in-clinic rehabilitation therapy.
At the end of those six weeks, all of them demonstrated improvements in their upper limb function. There was no statistically significant difference in the improvements observed between participants with an active device versus inactive device.
But after those six weeks, participants continued to do at-home exercises for 90 days. At the end of those 90 days, participants with an active device showed significantly greater improvements in their upper limb function than those with an inactive device.
In fact, 88 percent of participants with an active device showed clinically meaningful improvements, compared to only 33 percent of those with an inactive device.
While participants with an active device continued to improve throughout the home exercise phase, those with an inactive device actually lost some of the gains they had initially made.
“There’s a lot of therapy that can help you improve while you’re doing it, or immediately after you’re doing it, but then, there tends to be this drop-off,” Kimberley explained.
“So one of the things that excites me about this approach is that it might be a way to prevent that slide back to baseline when the therapy stops,” she added.
Although this treatment approach was found to be acceptably safe, there were three serious adverse events reported among participants following the surgical implantation of VNS devices.
In recent decades, advances have been made in the acute treatment of stroke. But fewer developments have occurred in the field of stroke rehabilitation and long-term recovery.
“This study potentially opens up a whole new paradigm to managing patients after stroke,” Dr. Karen Furie, chair of the Stroke Council for the American Heart Association and professor of neurology at the Warren Alpert Medical School of Brown University, told Healthline.
“It’s been one of the disappointing aspects of managing stroke that with all of the advances that have been made in acute care, we haven’t seen the same advances in recovery and rehabilitation,” she added.
Although the results of this study are promising, more research is needed to assess the safety and efficacy of combining stroke rehabilitation therapy with VNS.
“I think that it is potentially very exciting for stroke patients to have an additional adjunctive intervention to help with motor recovery,” Dr. Steven Messe, associate professor of neurology at the Hospital of the University of Pennsylvania and a fellow of the American Academy of Neurology, told Healthline.
“[But] this will require confirmation in a larger trial,” he said, “and it is worth noting that 3 of the 17 patients did have adverse events related to the implanting of the VNS, and thus the potential risks, and costs, will have to be weighed against the expected benefit.”
To further study this treatment approach, Kimberley and her fellow researchers are recruiting participants for a larger phase III clinical trial.
“This pivotal trial is what’s required by the FDA to ultimately make a decision on whether this should be something that’s available in the free marketplace or not,” she said.
A new pilot study found that vagus nerve stimulation, in addition to regular rehabilitation therapy, can double the rate of recovery for stroke patients.
But implanting a nerve stimulator can cause complications and experts say more study is needed before this is put into widespread use.