AI-driven, wrist-worn stimulation device reduces essential tremors

A wrist-worn wearable that harnesses artificial intelligence (AI) for noninvasive modulation of the nervous system appears beneficial in patients with essential tremor, enabling them to regain greater control over their upper limb movements for everyday activities.

The device, called Felix NeuroAI, is a transcutaneous peripheral nerve stimulation system. It uses a proprietary cloud-based AI model to deliver a tailored and dynamic electrical stimulation to the ulnar, median, and radial nerves throughout the day based on real-time feedback, reported Dr Rajesh Pahwa from the University of Kansas Medical Center in Kansas City, Kansas, US.

In the randomized, sham-controlled, double-blinded TRANQUIL study, Pahwa and colleagues showed that the device was efficacious and safe for the treatment of essential tremor.

Compared with sham, active treatment with the device was associated with a significantly greater reduction in the primary endpoint of the modified Activities of Daily Living (mADL) score on the Tremor Research Group Essential Tremor Rating Assessment Scale at 90 days (–6.9 vs –2.7 points; p<0.0001). Close to two-thirds of participants in the active group achieved at least a 20-percent reduction in mADL scores as opposed to just one-quarter of those in the sham group. [Pahwa R, et al, AAN 2025]

“The improvement [in mADL score] occurred within the first 2 weeks. The active group continued to be improved [through day 90], whereas the sham group slowly worsened,” Pahwa noted.

Results were consistent across subgroups defined by age, gender, tremor severity, and essential tremor medication use, he added.

Secondary outcomes also favoured active treatment, with both clinicians and patients reporting greater symptom improvement with Felix. The percentage of patients with any improvement on the Clinical Global Impression scale was significantly greater in the active group than in the sham group (69.4 percent vs 44.4 percent; p=0.02). Meanwhile, the percentage of patients who reported any improvement on the Patient Global Impression scale was only numerically greater in the active vs sham group (67.7 percent vs 50.0 percent; p=0.08).

Quality-of-life activity and psychosocial scores also improved more with active treatment than with sham, Pahwa said.

There were no serious device-related adverse events (AEs) documented, which confirmed the device’s strong safety profile, he continued. Mild skin irritation was the most common device-related adverse event, occurring in 34.9 percent of patients in the active group and in 7 percent of those in the sham group.

Four patients in the active group discontinued treatment due to AEs, including skin irritations (n=2), nausea (n=1), and worsening of existing arthritis in the thumb (n=1).

“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. 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 said.

He pointed out that Felix provides continuous, all-day tremor relief in patients with mild, moderate, or severe tremors, whether they are on medication or not. “The device can be used independently or alongside medication, offering a flexible, comprehensive solution for tremor management.”

Conducted in the US and China, TRANQUIL included 125 patients with essential tremor (mean age 64.9 years, 50 percent female). The mean tremor duration was 11.4 years, and 40.0 percent were taking at least one medication for tremor. The patients were randomly assigned at a 2:1 ratio to treatment with Felix or sham at home for 90 days.