SAN DIEGO — Transcutaneous peripheral nerve stimulation delivered via a wristband has shown promise in treating essential tremor (ET), a common movement disorder that significantly affects an individual’s ability to perform daily activities.
The Felix NeuroAI wristband (Fasikl Inc.) is an investigational wearable designed to provide dynamic, all-day, personalized relief of ET. It’s powered by advanced artificial intelligence (AI) to continuously adapt stimulation on the basis of real-time feedback.
In the TRANQUIL study, the Felix NeuroAI wristband significantly reduced tremors and showed statistically and clinically significant improvement in the users’ ability to perform daily activities compared with sham stimulation.
“The TRANQUIL study represents what could be a shift in how we approach essential tremor treatment, a condition for which new options are sorely needed,” principal investigator Rajesh Pahwa, MD, professor of neurology, University of Kansas School of Medicine, and director of the Movement Disorder Program at The University of Kansas Health System, Kansas City, Kansas, said in a news release.
“Although oral medications are often used to treat essential tremor, they can be frequently unsatisfactory, and while deep brain stimulation and focused ultrasound are effective, they require surgical intervention,” Pahwa added.
He presented the results on April 8 at the American Academy of Neurology (AAN) 2025 Annual Meeting.
Tailored Noninvasive Stimulation
Pahwa explained that the pathophysiology of tremor is believed to involve a brain circuit that includes the ventral intermediate nucleus (VIM) of the thalamus. It is believed that the electrical stimulation of the peripheral nerves in the wrist can modulate the activity in the VIM.
Using a proprietary cloud-based AI model, the Felix NeuroAI wristband delivers tailored and dynamic electrical stimulation to the ulnar, median, and radial nerves throughout the day.
The TRANQUIL study was a randomized, double-blind, sham-controlled clinical trial that enrolled 125 adults (50% women; mean age, 64 years) with long-standing ET across 12 clinical sites in the United States and China.
They were randomly allocated (2:1) to wear either the Felix NeuroAI wristband or a sham stimulation device during waking hours for 90 days. About 40% of patients were taking at least one medication for tremor. There were no clinical or demographic differences between the two groups.
The primary endpoint was change in the modified Activities of Daily Living (mADL) score from the Tremor Research Group Essential Tremor Rating Assessment Scale, a commonly used tremor assessment that combines 10 ADLs and 2 clinical assessments of tremor.
At the end of the 90-day period, the Felix NeuroAI wristband showed clear superiority over the sham wristband, with a statistically significant mean reduction of 6.9 points in mADL scores compared with 2.7 points in the sham group (P < .0001).
The “change separation” in mADLs started after 14 days, the study team said in their conference abstract. The benefits were consistent across age, gender, tremor severity, and medication use.
“Both the clinicians and patients were more likely to report improvement in symptoms at the end of the study in the patients that received active treatment, and quality of life was also improved more in the patients who were using the active device,” Pahwa reported during a press briefing.
There were no serious device-related adverse events. Mild skin irritation was the most common device-related adverse event.
The Felix NeuroAI wristband is currently under review at the US Food and Drug Administration.
Pahwa noted that the device could augment oral medication.
The TRANQUIL trial included patients who were taking their current tremor medications, either propranolol or primidone, he explained. “We still believe that these would be the drugs that would be tried first for tremor, and if there is an inadequate response, or patients cannot tolerate or don't have response to the oral medications, that’s when we would recommend using the current device,” he said.
Continuous, Personalized, Dynamic, Responsive
Commenting on this research for Medscape Medical News, Shaheen Lakhan, MD, PhD, a neurologist and researcher in Miami, said “neuromodulation is here to stay — and it’s only getting smarter. With the integration of AI, we’re entering an era where stimulation isn’t one-size-fits-all. Instead, devices can now learn from each individual’s patterns and needs, delivering personalized, adaptive doses of therapy in real time.”
“No two people will receive the same neuromodulation experience — and that’s a good thing. This precision approach not only boosts effectiveness but also increases the odds of meaningful improvement across a wide range of brain conditions,” Lakhan said.
“What’s striking about Felix NeuroAI is that it’s not just a wearable — it’s a dynamic, responsive therapy that meets patients where they are, moment to moment. As a neurologist, I see this as a shift from episodic, clinic-based care to continuous, personalized neuromodulation. For a condition like essential tremor, where medication and surgery aren’t ideal for everyone, this kind of AI-driven adaptability is a real leap forward — even if we’re still in early days,” Lakhan told Medscape Medical News.
“Imagine a retired teacher who’s always loved painting, but essential tremor has made it nearly impossible to hold a brush steady. Or a young professional who avoids business lunches because lifting a coffee cup draws too much attention. These are the kinds of patients who could benefit most from the Felix NeuroAI wristband,” Lakhan said.
Pahwa is a consultant for Fasikl Inc., Abbott, AbbVie, ACADIA, Acorda, Allevion, Amneal, Appello, Biogen, BioVie, Cala Health, Convatec, Genentech, Insightec, Jazz, KeifeRx, Kyowa, Lundbeck, Merz, Mitsubishi Tanabe, Neurocrine Biosciences, Ono, PhotoPharmics, PSG, REGENXBIO, Sage, Sun BioPharma, Supernus Pharmaceuticals, and UCB. Lakhan had no disclosures.
