Explainer · Sleep
Leg nerve stimulation eased hard-to-treat restless legs in 232 patients, in a study with no comparison group
Restless legs syndrome keeps many people awake, and some find medicines stop working. In a real-world study of a worn nerve-stimulation device, symptoms fell over 90 days, though without a placebo group.
- An observational study of 232 adults with moderate to severe restless legs that other treatments had not controlled.
- Each was prescribed a device worn just below the knees that stimulates a nerve in the lower leg.
- After 90 days, scores on a 40-point symptom scale fell by an average of 8.4 points; sleep problems also eased.
- More patients cut their doses of restless legs medicines than raised them, and there were no serious device harms.
- There was no placebo group, and placebo effects are known to be sizable in restless legs.
For people with restless legs syndrome, evenings can be the worst part of the day. Lying down to rest brings an uncomfortable urge to move, and getting up only helps for a while. Medicines can control it, but for some people they stop working well enough, and the most common drugs can make symptoms worse over time.
A study in the journal Sleep followed 232 hard-to-treat patients who were prescribed a worn nerve-stimulation device in routine care. Symptoms and sleep improved over 90 days, and more people cut their medicine doses than raised them. Unlike earlier trials of the device, though, this study had no comparison group.
What restless legs syndrome is
MedlinePlus explains that restless legs syndrome (RLS) causes a powerful urge to move your legs. The legs become uncomfortable when lying down or sitting, and moving helps, but not for long. It notes that RLS can make it hard to fall asleep and stay asleep.
Treatment starts with lifestyle changes such as regular sleep habits, relaxation and moderate daytime exercise, and then medicines. A group of drugs called dopamine agonists has long been used, but the authors note a shift away from dopamine agonists in clinical guidelines due to their risk for augmentation, meaning symptoms that grow worse or start earlier in the day with long-term use.
How the restless legs device works
The device goes by the name tonic motor activation. It consists of two therapy units positioned just below the knee, where the peroneal nerve, a nerve that runs down the outside of the lower leg, sits close to the skin. According to the authors, the system is designed to stimulate the afferent fibers of the peroneal nerve, the fibers that carry sensation from the legs to the brain.
The treatment is worn externally and has only been available for prescription since August 2023. The authors note that bilateral (both-leg) high-frequency peroneal nerve stimulation, the generic name for this approach, was the one treatment without drugs recommended in 2025 clinical guidelines from the American Academy of Sleep Medicine.
How the real-world device study was run
The study enrolled 325 patients prescribed the stimulator across many clinics. Of these, 232 adults with refractory, moderate to severe RLS met the criteria for the main analysis, refractory meaning their symptoms were not controlled by earlier treatment. Their average age was 67, and 60% were women.
The main measure was a standard 40-point rating of symptom severity, filled in before treatment and again after 90 days. The team also tracked a sleep problems score, clinicians’ ratings of improvement, changes in other restless legs medicines, and side effects.
What happened to symptoms and sleep
Symptom scores fell. The change in IRLS score at day 90 was -8.4 points on the 40-point scale, from an average starting score of about 25. Clinicians rated 64% of patients as responders, and the sleep problems score improved as well.
Medicine use moved in a helpful direction. Reductions to adjunctive RLS medication dosage were more common than increases: 19% of patients cut a dose, against 11% who raised one. There were no severe or serious device-related adverse events, and no patient characteristic predicted who would benefit most.
Why a restless legs option without drugs matters
People whose restless legs resist medicine have fewer options, and long-used drugs can cause augmentation. A device that eases symptoms, and lets some patients reduce their medicine, would be a useful addition. The authors conclude that in real-world clinical practice, the device is safe and effective at reducing RLS symptoms and improving sleep in adults with moderate-to-severe refractory RLS.
What an uncontrolled device study cannot show
The biggest limit is that there was no placebo group. People with restless legs often improve when they start any treatment they expect to help. In three earlier randomized trials of the device, people given a sham, or fake, version improved by 3.0 to 3.8 points. The 8.4-point improvement here was larger, but comparing across studies is not the same as testing against a sham in the same people. Exercise, alcohol and caffeine were not recorded, and lifestyle changes could also have contributed.
The patients were shaped by who prescribed the device and who had insurance to cover it, and the prescribers were early adopters in the first years of sales. Use was not objectively tracked, and 90 days is a short time for a long-lasting condition; one-year results are planned. The study was set up as a post-market study of the device.
What this changes for people with restless legs
For adults whose restless legs remain troublesome despite treatment, this worn device is another option to discuss with a sleep specialist, particularly for those worried about the long-term effects of dopamine agonists. The evidence now includes both earlier trials against a sham and this larger real-world study.
Anyone considering a change should not stop or cut medicines without a doctor’s advice. The planned one-year results will show whether the benefit holds.
People also ask
What did the study find?
The change in the International Restless Legs Syndrome Study Group (IRLS) score at day 90 was -8.4 points. The clinician-rated responder rate was 64%, and a sleep problems score improved by 12.8 points. Reductions to other restless legs medicines were more common than increases (19% vs 11%). There were no severe or serious device-related adverse events.
How does the device work?
It is called tonic motor activation, or high-frequency peroneal nerve stimulation. Two units are worn just below the knees, over a spot where the peroneal nerve runs close to the skin, and deliver electrical stimulation designed to act on the nerve's sensory fibers.
What does refractory mean?
That symptoms have not been controlled well enough by other treatments. The patients in this study had moderate to severe restless legs despite earlier care.
Why does the lack of a placebo group matter?
People with restless legs often improve when given any treatment they expect to help. In three earlier randomized trials of this device, people using a sham, or fake, version improved by 3.0 to 3.8 points. The 8.4-point change here was larger, but without a comparison group in the same study the two cannot be compared directly.
Is this a replacement for medicine?
Not necessarily. Many patients kept taking medicines, though some reduced their doses. Decisions about medicines should be made with a doctor.
Who might ask about this device?
Adults whose restless legs are still troublesome despite treatment, in discussion with a doctor who treats sleep disorders. This is general information rather than medical advice.