"I would absolutely consider these findings practice-changing," coauthor Dr. Charles Liu of Keck Medicine of USC told Reuters Health by email.
"For a long time," he said, "the field has been convinced that the combination of neuromodulation and task-specific practice (rehabilitation) can be synergistic, essentially augmenting and accelerating Hebbian plasticity, to both accelerate the progress of rehab and raise the plateau of eventual performance."
Combining the two therapies, "greatly expands the horizon of possibilities not only for stroke, but theoretically for all other types of neurological disorders," noted Dr. Liu, who directs the USC Neurorestoration Center in Los Angeles.
"The immediate next steps related to combined VNS and rehab (task-specific practice) are to conduct pilot trials with patients already implanted with VNS, either as part of this trial or for other indications," he said.
"Almost immediately," he added, "it would most certainly be reasonable to combine VNS with other types of rehabilitation therapies for other indications."
As reported in The Lancet, Dr. Liu and colleagues conducted a pivotal, randomized, triple-blind, sham-controlled trial in 19 stroke rehabilitation centers in the U.K. and the U.S. Participants with moderate-to-severe arm weakness, at least nine months after ischemic stroke, were randomly assigned to either rehabilitation paired with active VNS (VNS group; 53 participants) or rehabilitation paired with sham stimulation (control group; 55 participants).
Participants' mean age was about 60, nearly two-thirds were men and 79% were white. The mean time from stroke was 3.2 years.
All participants were implanted with a VNS device. The VNS group received 0.8-mA, 100-ms, 30-Hz stimulation pulses, lasting 0.5 seconds. The control group received 0-mA pulses.
All participants also underwent in-clinic therapy three times per week for six weeks, followed by a home exercise program.
One hundred and six patients completed the study (one patient in each group did not). On the first day after completion of in-clinic therapy, the mean Fugl-Meyer Assessment-Upper Extremity (FMA-UE) score had increased by 5.0 points in the VNS group versus 2.4 points in the control group (P=0.0014).
At 90 days after in-clinic therapy, a clinically meaningful response on the FMA-UE score was achieved in 47% of patients in the VNS group versus 24% of controls (P=0.0098).
Dr. Liu said, "The study included subjects between nine months and 10 years after stroke. Thus, a large number of patients who have plateaued on traditional therapy can potentially benefit and should be given this option. As the field gains additional knowledge about the use of this approach, specific guidelines will be developed."
"Clinicians should follow the progress of this and other similar approaches that will surely emerge in the near future to become a routine part of our practice to restore neurological function," he concluded.
Dr. Heidi Schambra, director of the Neuro-Epidemiology Division and of Neurology Research Strategy at NYU Langone Health in New York City, commented to Reuters Health by email, "This study showcases an exciting and growing area in neurorehabilitation: the use of rationally guided technology to accelerate recovery."
"VNS could serve as an adjuvant to training to boost its efficacy - essentially giving rehabilitation more bang for the buck," said Dr. Schambra, who wasn't involved in the research. "This approach may very well become a tool in our treatment repertoire."
That said, she noted, "Pairing VNS with training caused a boost in recovery compared to training alone, but the improvements were modest and not seen in every subject. Thus, this approach is unlikely to fully restore function to normal levels, but it is the first step in the right direction."
Further, she said, "This approach has not been tested in people early after stroke or in people with mild or severe impairment, so it is difficult to know if the approach would be more, less, or equally effective."
"VNS would not be appropriate in individuals who have prior vagus nerve injury, difficulty swallowing, or other neurostimulators or pacemakers already implanted," she added.
The study was funded by MicroTransponder, which produces vagus nerve stimulator. Three coauthors are employees and four have received fees from the company.
SOURCE: https://bit.ly/3nRBoKk The Lancet, online April 24, 2021
By Marilynn Larkin
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