Safety and Efficacy of a Wrist-worn Vibratory Stimulation Wearable for Upper Limb Tremor Reduction in Essential Tremor (ULTRE): A Randomized, Controlled Trial
Fatta Nahab1, Daniel Carballo2, Allison Davanzo2, Kristi Winterfeldt2, Srikar Nekkanti2, Han Kim2, Ludy Shih3, Rodger Elble4
1Department of Neurology, UCSD, 2Encora Therapeutics, 3Department of Neurology, Beth Israel Deaconess Medical Center, 4Department of Neurology, Southern IL Univ Sch of Med
Objective:
To evaluate the safety, tolerability, and efficacy of a wrist-worn vibratory stimulation wearable from Encora Therapeutics for Upper Limb Tremor Reduction in Essential Tremor (ULTRE) by comparing two vibrotactile stimulation paradigms against an inactive sham in patients with essential tremor (ET).
Background:
ET is a prevalent movement disorder characterized primarily by upper limb tremor. Most patients respond inadequately to existing treatments. The wrist-worn device delivers targeted vibrotactile stimulation to reduce tremor severity.
Design/Methods:
The ULTRE study is a prospective, double-blind, randomized, sham-controlled, cross-over clinical trial. Pulsed (low-amplitude stimulation at 0.125Hz) and Continuous (high-amplitude stimulation at the tremor frequency) paradigms were compared with inactive Sham. Subjects with tremor severity ≥2 in one upper limb Essential Tremor Rating Assessment Scale task (TETRAS items 4, 6, and 8) and ≥3 in one Bain & Findley Activities of Daily Living task (BF-ADL items 2, 4, 17, and 22) were randomized 1:1:1. TETRAS and BF-ADL tasks performed before (Baseline), during, and after stimulation were both self rated (BF-ADL) and evaluated by blinded experienced video raters (TETRAS). Primary endpoints were tolerability and adverse events (AEs). Secondary endpoints were changes in BF-ADL (4 tasks; scores: 4-16) and TETRAS (5 tasks; scores: 0-20) composite scores.
Results:
Mild-to-moderate, non-serious device-related AEs occurred in 5.6% of participants, all resolving without intervention; and 94% rated the device as comfortable. Both stimulation patterns resulted in statistically significant (p<0.05) improvements vs. baseline in BF-ADL (Pulsed: 1.93±0.56; Continuous: 1.32±0.57) and TETRAS (Pulsed: 1.40±0.60; Continuous: 0.62±0.56). Pulsed outperformed Sham in both BF-ADL and TETRAS (p<0.01), and Continuous outperformed Sham in BF-ADL (p<0.05). There appeared to be a cumulative benefit over the treatment period.
Conclusions:
The Encora Device was safe and well-tolerated. Both stimulation patterns produced statistically significant improvements compared to Baseline and Sham. A beneficial response to Pulsed stimulation was unexpected, and the optimum stimulation pattern requires further study.
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