US-based MicroTransponder has reported positive long-term results for stroke patients who received the company’s paired vagus nerve stimulation (VNS) therapy.
The data, published in the medical journal Stroke, demonstrated significant and meaningful clinical improvements that lasted a year.
Paired VNS is a therapy that combines electrical stimulation with rehabilitation training. iMicroTransponder’s system, called Vivistim, is an implantable pulse generator that stimulates the vagus nerve to promote neural plasticity and improve motor function.
Vivistim was approved by the US Food and Drug Administration (FDA) in 2021 based on data from the pivotal, multi-centre, triple-blinded, randomised controlled clinical trial, VNS-REHAB, published in The Lancet.
MicroTransponder’s system is approved for the treatment of moderate to severe upper extremity motor deficits associated with chronic ischaemic stroke. The standard protocol is for stroke survivors to undertake in-clinic Vivistim therapy during 90-minute sessions three times a week for six weeks.
The results in Stroke are a long-term analysis of VNS-REHAB. Data shows improvements in motor impairment and functional activity as measured by the Fugl-Meyer Assessment –Upper Extremity (FMA-UE) and the Wolf Motor Function Test (WMFT), respectively.
An ischaemic stroke occurs when a vessel supplying blood to the brain is obstructed. It accounts for approximately 87% of all strokes.
Vivistim therapy includes a self-initiated segment, allowing stroke survivors to swipe a magnet across the implant to activate vagus nerve stimulation during daily life.
MicroTransponder stated that the one-year study analysis demonstrates that self-initiated paired VNS therapy may facilitate the continued refinement and consolidation of behaviourally relevant activities, resulting in long-term, persistent improvements.
MicroTransponder's CEO Richard Foust said: “While patients who have lost mobility in their hands and arms following ischaemic stroke have previously been limited in their treatment options, the Vivistim paired VNS therapy is a breakthrough intervention in establishing a new standard in the stroke continuum of care.
"With this data, healthcare professionals, including neurologists, physiatrists, neurosurgeons, occupational therapists and physical therapists, can confidently pursue Vivistim therapy as an evidence-based, clinically proven intervention for ischaemic stroke survivors who are 6 months or more post-stroke."
The long-term data follows a $65m raise by the company in March 2025.
VNS was primarily developed as a treatment for seizures, but researchers found it also had beneficial effects in promoting muscle rehabilitation for stroke patients. There is ongoing research into non-invasive forms of the technology, such as a study at King’s College Hospital trialling transcutaneous (through the skin) vagus nerve stimulation (TVNS).
The global neuromodulation market is forecast to grow to $12.6bn by 2034, up from $6.6bn in 2024. Sales of VNS systems are estimated to contribute $1.3bn to that market. Analysis by GlobalData shows that Boston Scientific currently occupy the largest market share.
