Key messages
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For people who have had a stroke, it is unclear whether vagus nerve stimulation (VNS) paired with rehabilitation is better than rehabilitation alone for improving shoulder, arm, forearm, wrist, and hand movement, and quality of life up to 3 months after treatment.
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VNS may result in little to no increased risk of unwanted effects. The included studies reported few unwanted effects, and none were clearly related to VNS treatment.
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This Cochrane review highlights research gaps, such as the lack of long-term follow-up after treatment. Some studies looked at quality of life but did not always report the results.
What is the vagus nerve?
The vagus nerve is a long nerve (a bundle of fibres like an electrical cable) that runs from the head into the body. It helps regulate essential body functions, such as heart rate, breathing, and digestion.
How might stimulation of the vagus nerve help people who have had a stroke?
During a stroke, blood flow to the brain is interrupted, causing brain cells to die. People who survive a stroke often have difficulty with movement. Their shoulders, arms, wrists, and hands (upper limbs) may not work properly due to reduced strength and co-ordination. This affects their ability to perform daily activities. Recovery of upper limb function after stroke may be slow or incomplete. In addition to normal rehabilitation treatments, such as medication and physiotherapy, stimulating the vagus nerve with an electrical signal (VNS) might improve communication between the brain and the body and help people recover their upper limb function. Electrical signals can be sent to the vagus nerve using a surgically implanted device (invasive VNS) or electrodes on the skin (non-invasive VNS). How VNS works is not fully understood, but may help by reducing inflammation and changing the activity of different body chemicals. Unwanted side effects of VNS may include hoarseness and numbness in the throat-chin area, shortness of breath, and slow heart rate. Also, there is risk of infection and bruising in people who have surgically implanted VNS.
What did we want to find out?
We wanted to find out if VNS alongside standard rehabilitation treatments helped people who had a stroke recover better upper limb function than by rehabilitation alone. Also, whether there were any unwanted effects and any effects on quality of life. We mainly looked at the effects of VNS 6 to 12 weeks after treatment.
What did we do?
We searched for studies that compared VNS paired with rehabilitation versus rehabilitation alone in people who had a stroke. People in the studies had to be 18 years or older, and could be at any stage of recovery from their first stroke. We checked the studies for quality, combined their results, and rated our confidence in the evidence based on their methods, size, and quality.
What did we find?
We found 10 studies that included 547 participants. The included studies took place in China, the UK, the USA, and Italy. Nine were written in English, and one in Chinese. All VNS treatments were paired with rehabilitation and compared with rehabilitation alone. Three studies used invasive VNS, and seven studies used non-invasive VNS. All studies included both men and women. Either outpatient hospital services or health centres treated most people. All studies measured results 6 to 12 weeks after treatment, three studies measured 6 months after treatment, and one study measured 12 months after treatment. We also found 23 ongoing studies, and 14 studies that are complete but their results are not yet available.
Main results
We are very uncertain about the effect of VNS paired with rehabilitation on upper limb movement (10 studies, 499 people), and quality of life (3 studies, 180 people) 6 to 12 weeks after treatment compared to rehabilitation alone. VNS may result in little to no increased risk of unwanted effects (8 studies, 416 people). This corresponds to about 42 out of 1000 people experiencing unwanted effects with VNS paired with rehabilitation compared with 19 out of 1000 people with rehabilitation alone.
What are the limitations of the evidence?
Our confidence in the results of this review is very low to low. Studies showed inconsistent results and included only small numbers of people. Studies were also quite different from each other as they used different types of VNS and different kinds of rehabilitation, which made it difficult to compare the results.
While a few included studies were of good quality, others had problems with how they were planned and reported, which makes their results less trustworthy. Not all study results have been published yet.
This Cochrane review highlights research gaps, such as the lack of long-term follow-up and lack of results that are important to people who have had a stroke. Some studies looked at quality of life but did not always report the results.
How up to date is this evidence?
The evidence is up to date to May 2025.
مطالعه چکیده کامل
اهداف
To assess the potential benefits and harms of vagus nerve stimulation (VNS) as an add-on treatment to rehabilitate people who have post-stroke UE motor function impairments and activity limitations.
روشهای جستوجو
We searched for published trials in the Cochrane Library, MEDLINE, Embase, Scopus, PsycINFO, CINAHL and PEDro. We also handsearched for reference lists and looked for other relevant studies on Google Scholar. We performed the searches up to May 2025.
نتیجهگیریهای نویسندگان
Comparing VNS paired with rehabilitation to rehabilitation alone, we found very uncertain evidence for the effects on UE motor function, UE activity, and quality of life in the short-term. VNS may result in little to no increased risk of SAEs.
The body of evidence on the benefits and harms of VNS is limited by the risk of bias in the included studies, the small number of included studies, and the relatively small sample sizes.
حمایت مالی
This Cochrane review did not receive any specific funding.
ثبت
Protocol (2024) DOI: 10.1002/14651858.CD015859
