Assessment of the Safety and Efficacy of the Felix NeuroAI Wristband in Essential Tremor (TRANQUIL)

Assessment of a Novel NeuroAI-powered Transcutaneous Neuromodulation Device in Alleviating Tremor Symptoms and Enhancing Quality of Life for Patients With Upper Limb Essential Tremor

The goal of this clinical study is to compare Felix NeuroAI Wristband and sham device in patients with essential tremor. The main question it aims to answer is:

• Is Felix a safe and efficacious treatment for patients with essential tremor?

Participants will be treated with either Felix or Sham for a period of up to 90 days. After that, they will be eligible to participate in a long-term, open-label study and be treated with Felix.

Study Overview

• Status: Completed
• Conditions: Essential Tremor
• Intervention / Treatment: Device: Felix NeuroAI Wristband; Device: Sham Device

Detailed Description

The TRANQUIL study is a prospective, randomized, sham-controlled, double-blinded, multi-center, multi-region trial. The objective of this clinical investigation is to evaluate the safety and effectiveness of the Felix NeuroAI Wristband to aid in the relief of upper limb tremor in adults with essential tremor (ET).

• Study Type: Interventional
• Enrollment (Actual): 125
• Phase: Not Applicable

Contacts and Locations

Study Locations

• China
  • Beijing, China, 100053
    • Xuanwu Hospital Capital Medical University
  • Tianjin, China, 300052
    • Tianjin Medical University General Hospital
  • Zhejiang
    • Hangzhou, Zhejiang, China, 310016
      • Sir Run Run Shaw Hospital
    • Hangzhou, Zhejiang, China, 310003
      • The first Affiliated Hospital, Zhejiang University School of Medicine
• United States
  • Arizona
    • Phoenix, Arizona, United States, 85013
      • Barrow Neurological Institute
  • California
    • Palo Alto, California, United States, 94301
      • Parkinson's Research Centers of America - Palo Alto
  • Florida
    • Boca Raton, Florida, United States, 33486
      • Parkinson's Disease and Movement Disorders Center of Boca Raton
  • Kansas
    • Kansas City, Kansas, United States, 66160
      • The University of Kansas Medical Center
  • New York
    • Commack, New York, United States, 11725
      • Parkinson's Research Centers of America - Long Island
    • New York, New York, United States, 10032
      • Columbia University Irving Medical Center
  • Ohio
    • Cincinnati, Ohio, United States, 45221
      • University of Cincinnati
  • Texas
    • Houston, Texas, United States, 77030
      • Houston Methodist Research Institute

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• At least 18 years of age.
• Willing to provide written, informed consent to participate in the study.
• A clinical diagnosis of ET by a movement disorder specialist.
• For the dominant hand, a tremor severity score of 2 or higher as measured by one of the TETRAS Performance Subscale (PS) tasks (items 4, 6, 7, and 8) and a total score of 7 or higher across these items. If applicable, this must be met while the patient is on ET treatment.
• Stable dosage of anti-tremor medications, if applicable, for 30 days prior to study entry.
• Stable dosage of antidepressant medications, if applicable, for 90 days prior to study entry.
• Familiar with operating a touch-screen smartphone and connecting to Wi-Fi internet at home.
• If necessary, have a dedicated caregiver to help with study required activities, such as putting on the study device, etc.

• Willing to comply with study protocol requirements including:

  1. Remaining on a stable dosage of anti-tremor and antidepressant medications, if applicable, during the course of the study.
  2. Do not start any new anti-tremor treatment during the course of the study (except the assigned treatment in the study).
  3. Remaining on stable caffeine consumption, if applicable, during the course of the study.
  4. No alcohol or marijuana consumption the day before a study visit.
  5. Do not share study/device-related information on the internet or with other study patients.

Exclusion Criteria:

• Prior limb amputation or any known symptomatic peripheral neuropathy condition of the involved upper extremity.
• Prior surgical intervention for ET such as deep brain stimulation or thalamotomy.
• Moderate to severe alcohol use disorder (AUD) as per Diagnostic and Statistical Manual of Mental Disorders Fifth Edition (DSM-5) (the presence of at least 4 symptoms or more).
• Any current drug abuse.
• Use of recreational drugs other than marijuana.
• Current unstable epileptic conditions with a seizure within 6 months of study entry.
• Other possible causes of tremor such as drug-induced tremor, enhanced physiological tremor, dystonia, and Parkinson's disease.
• Pregnant or nursing subjects and those who plan pregnancy during the course of the study.
• Swollen, infected, inflamed areas, or skin eruptions, open wounds, or cancerous lesions of skin at the stimulation site.
• Known allergy to adhesive bandages.
• The presence of any cognitive or other impairment that in the judgement of the investigator will impede the assessment of study outcomes.
• Botulinum Toxin injection for hand tremor within 4 months prior to study enrollment.
• History of use of other transcutaneous afferent patterned stimulation (TAPS) devices such as Cala Trio.
• Subject is currently participating or has participated in another interventional clinical trial in the last 30 days which may confound the results of this study, unless approved by the Sponsor.
• Subject is unable to communicate with the investigator and study staff.
• Any health condition that in the investigator's opinion should preclude participation in this study.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Double

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Felix NeuroAI Wristband	Device: Felix NeuroAI Wristband; The Felix NeuroAI Wristband (Felix) is a wrist-worn, noninvasive, transcutaneous neurostimulation system. Using a proprietary artificial intelligence (AI) algorithm, stimulation will be automatically adapted to patient's needs with the goal to provide full day relief of upper limb tremor.
Sham Comparator: Sham Device	Device: Sham Device; The sham device has the same exterior appearance and components as the Felix device and is used the same way (without delivering the treatment).

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in Tremor Research Group Essential Tremor Rating Assessment Scale (TETRAS) Modified Activities of Daily Living (mADL) Score From Baseline Pre-stimulation to Day 90	TETRAS mADL score is a composite sum of items 2 to 11 of the TETRAS ADL subscale and items 6 (bilateral) and 7 (dominant hand) of the TETRAS performance subscale (PS). Each item is scored from 0 to 4, indicating increasing severity of tremor. TETRAS mADL score is calculated as the sum of all 13 items and ranges from 0 to 52.	90 days

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in Tremor Research Group Essential Tremor Rating Assessment Scale (TETRAS) Modified Activities of Daily Living (mADL) Score From Baseline Pre-stimulation to 14 Days, 30 Days, 60 Days	TETRAS mADL score is a composite sum of items 2 to 11 of the TETRAS ADL subscale and items 6 (bilateral) and 7 (dominant hand) of the TETRAS performance subscale (PS). Each item is scored from 0 to 4, indicating increasing severity of tremor. TETRAS mADL score is calculated as the sum of all 13 items and ranges from 0 to 52.	14 days, 30 days, and 60 days
Tremor Research Group Essential Tremor Rating Assessment Scale (TETRAS) Performance Subscale (PS) Dominant Hand Score	The sum of TETRAS PS items 4 (3 sub-items), 6, 7, and 8 for the dominant hand. Each item is scored by physician from 0 to 4, indicating increasing severity of tremor. TETRAS PS score is calculated as the sum of all 6 items and ranges from 0 to 24. Items 4 and 8 can only assess in-clinic, because clinical follow-up at 14 days and 60 days are conducted remotely, this outcome measure is not available for those timepoints.	Baseline, 30 days, and 90 days
Clinical Global Impression of Severity (CGI-S)	Physician rating on a 7-point scale, from 1 (normal) to 7 (amongst the most extreme tremor)	Baseline, 30 days, and 90 days
Patient Global Impression of Severity (PGI-S)	Patient rating on a 7-point scale, from 1 (normal) to 7 (amongst the most extreme tremor)	Baseline, 14 days, 30 days, 60 days, and 90 days
Clinical Global Impression of Improvement (CGI-I)	Physician rating of tremor improvement on a 7-point scale, from 1 (very much improved) to 7 (very much worse)	Baseline, 30 days, and 90 days
Patient Global Impression of Improvement (PGI-I)	Patient rating of tremor improvement on a 7-point scale, from 1 (very much improved) to 7 (very much worse)	Baseline, 14 days, 30 days, 60 days, and 90 days
Quality of Life in Essential Tremor Questionnaire (QUEST)	QUEST Total activity and psychosocial score is a 27-item scale that covers Work and Finances, Hobbies and Leisure, Physical, and Psychosocial aspects of QOL. Each item is rated based on how frequent does tremor interfere with this activity, the answers are Never/No (0), Rarely (1), Sometimes (2), Frequently (3) Always/Yes (4). The final total score was calculated: the sum of individual scores / total possible points (i.e., 27x4) times 100.	Baseline and 90 days

Collaborators and Investigators

• Sponsor: Fasikl Inc.

Publications and helpful links

General Publications

• Ondo WG, Lv W, Zhu X, Hu Y, Isaacson SH, Yuan Y, Espay AJ, Kreitzman D, Kuo SH, Brillman S, Shill HA, Lyons KE, Yang Z, Zhao Q, Zhang Z, Pahwa R. Transcutaneous Peripheral Nerve Stimulation for Essential Tremor: A Randomized Clinical Trial. JAMA Neurol. 2025 Dec 1;82(12):1235-1242. doi: 10.1001/jamaneurol.2025.3905.

Study record dates

Study Major Dates

• Study Start (Actual): February 27, 2024
• Primary Completion (Actual): October 31, 2024
• Study Completion (Actual): November 6, 2025

Study Registration Dates

• First Submitted: January 11, 2024
• First Submitted That Met QC Criteria: January 23, 2024
• First Posted (Actual): January 31, 2024

Study Record Updates

• Last Update Posted (Actual): July 9, 2026
• Last Update Submitted That Met QC Criteria: June 12, 2026
• Last Verified: June 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Central Nervous System Diseases; Nervous System Diseases; Movement Disorders; Essential Tremor
• Other Study ID Numbers: FSK-CIP-2

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: IPD will not be shared with other researchers.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: Yes
• product manufactured in and exported from the U.S.: No