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Encora X1 is a prescription wristband cleared in the United States to help relieve hand tremor in the treated limb while stimulation is running, in adults with essential tremor. The FDA recorded its 510(k) clearance on 5 February 2026. That scope matters when reading the device’s development story or a headline about a wearable for shaking hands. FDA decision, Indications for use, PDF page 4
Essential tremor is a distinct movement-disorder syndrome. The International Parkinson and Movement Disorder Society describes difficulties during activities such as eating, drinking and writing, and explains that tremor can have several different causes. A device claim therefore needs a named condition and purpose, even when the outward movement looks similar. Specialist background
Vibration is the active part of the wristband
Encora uses mechanical stimulation at the wrist. MIT’s October development account describes small vibrations intended to influence sensory signals travelling through the wrist’s nerves. The FDA submission describes continuous and pulsed stimulation modes, adjusted to characteristics of the person’s tremor, alongside motion sensors and a rechargeable stimulator. Development account, Device description, PDF pages 6–7
This gives the wearable a different job from a watch that records movement or sends an alert: stimulation is the intervention being evaluated. The relevant questions concern what happens during use, which activities improve and how the result was compared with a control.
MIT traces the project to a 2017 classroom demonstration involving a man with Parkinson’s disease. Its account also explains the later shift towards essential tremor. The FDA’s cleared indication concerns essential tremor; the earlier demonstration does not extend that indication to Parkinson’s disease. Project history
Two studies provide different kinds of evidence
Encora’s FDA submission describes a randomized crossover study called ULTRE and a separate 90-day home-use study. Their comparisons answer different questions. Clinical testing, PDF pages 10–19
| Study | Comparison and analysed population | Main limitation to retain |
|---|---|---|
| ULTRE | Participants used continuous stimulation, pulsed stimulation and an inactive sham in randomized order; effectiveness population 43 | A feasibility study without prespecified primary effectiveness endpoints or formal hypothesis testing; results are descriptive |
| 90-day home use | Single-arm study, with 59 people in the effectiveness population across two cohorts | Participants knew they were using the device; blinded task raters do not provide a parallel sham group |
The ULTRE registration records 71 actual enrollees and lists tolerability and safety as primary outcomes. It also describes daily-activity assessments, including using a spoon and pouring from a carton. The FDA summary separates the 71-person safety population from the 43-person effectiveness population. Enrollment and an analysed result therefore need their own denominators. Registered study design, Analysis populations, PDF page 13
A task score also has a specific meaning. In ULTRE, the submission reports at least a one-point improvement on its four-task daily-activity composite in 30 of 40 participants assessed during continuous stimulation and 28 of 40 assessed during pulsed stimulation, compared with 20 of 42 assessed during sham. These are the reported descriptive comparisons within a crossover study. They cannot be added together as different groups of patients, or turned into a probability that someone’s tremor will disappear. Table 6, PDF pages 14–15
Relief during use leaves further questions
The 90-day study extends observation into use at home, but its design cannot establish how participants would have fared over the same period with a sham device. The indication itself concerns relief during stimulation; it does not claim lasting disease modification after the device is removed. Home-use design and indication
Harms remain part of the evidence. The submission reports device-related adverse events in five of 71 ULTRE safety participants and seven of 60 home-use safety participants. It describes those events as non-serious and self-resolving, with examples including numbness, skin symptoms and discomfort. Those observations describe the studied groups, rather than guaranteeing an individual user’s experience. Safety tables, PDF pages 14 and 17–18
Access is another separate question. MIT’s 2 October account describes work on distribution and insurance coverage. Dated distribution plans
That dated account and the US clearance do not establish current availability, reimbursement or authorization in another country.