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.

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).

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.

IPD will not be shared with other researchers.