Consistent TAPS Use Associated With Underlying Tremor Improvement in Essential Tremor

Regular use of transcutaneous afferent patterned stimulation (TAPS) was associated with reduced tremor severity in patients with essential tremor (ET), with improvements observed approximately 16 hours after the last stimulation session. The findings come from a recent retrospective analysis of the PROSPECT trial (NCT03597100), published in Tremor and Other Hyperkinetic Movements.¹

Overall, more than 80% of patients met responder criteria for improvements in underlying tremor severity on both patient- and investigator-rated scales at 1 and 3 months. While previous studies demonstrated acute and short-term benefits with the wrist-worn therapy, these findings suggest that consistent use may also reduce baseline tremor severity. However, the absence of a control arm limits conclusions about the magnitude of the treatment effect.

PROSPECT enrolled 263 patients with ET at 26 US sites, who were instructed to use TAPS twice daily for 3 months.² TAPS delivers alternating bursts of stimulation to the median and radial nerves at a frequency calibrated to each patient’s tremor. Prior work has distinguished "acute" effects, measured during stimulation, from "lasting" effects, measured in the minutes to hours afterward.³

The study, conducted by lead author Stuart H. Isaacson, MD, FAAN, director of the Parkinson’s Disease and Movement Disorders Center of Boca Raton in Florida, defined underlying improvement as a change in the prestimulation baseline after weeks to months of use. Authors compared prestimulation scores at enrollment with those at the 1- and 3-month visits, which were obtained after a mean (SD) washout of 16.2 (4.7) hours.

“We looked at patients before their stimulation and evaluated their tremor as time went on,“ Isaacson told NeurologyLive^® in a recent interview. ^“We’re able to conclude that with consistent use of the device, there is improvement not only acutely, with each stimulation session lasting hours, but also in underlying tremor between sessions, which seems to improve progressively with ongoing and consistent use.”

The outcomes were the patient-rated 8-item Bain & Findley Activities of Daily Living (BF-ADL; range, 8-32) and the investigator-rated 6-item Essential Tremor Rating Assessment Scale (TETRAS; range, 0-24). A responder was a patient who improved by at least 1 point on any BF-ADL task rated 3 or higher at enrollment, or on any TETRAS task rated 2 or higher. The 1-point BF-ADL threshold aligns with Medicare coverage criteria for external upper limb tremor stimulators.

Improvement Across Scales and Usage Levels

Among 192 patients with data at both visits, mean prestimulation BF-ADL scores improved by 2.0 points at 1 month and 2.7 points at 3 months (both P .001), from 18.4 to 15.8. TETRAS scores improved by 0.8 and 0.7 points, respectively (both P <.001). BF-ADL responder rates were 84.4% at 1 month and 85.4% at 3 months, and TETRAS responder rates were 81.2% and 82.3%. At 1 month, 76.6% of patients had at least 1 BF-ADL task shift from severe or moderate tremor to mild or no tremor, and that figure rose to 81.2% at 3 months.¹

READ MORE: FDA Clears Cala kIQ Plus for Essential Tremor and Parkinson Disease Hand Tremor

Patients averaged 1.4 sessions per day rather than the 2 the protocol specified. Patients who used the device about once daily improved by 1.4 BF-ADL points at 1 month and 2.7 points at 3 months. Their 3-month TETRAS improvement, however, was 0.3 points, compared with 1.0 point among more frequent users. The subgroup data were descriptive. This analysis did not report safety outcomes; PROSPECT’s safety findings appeared in the original trial report.^1,2

Clinical Context and Limitations

A 2026 International Parkinson and Movement Disorder Society evidence-based review concluded that randomized trials with at least 1 month of follow-up are insufficient to confidently support the efficacy of available medical treatments for ET.⁴ That gap has fueled interest in noninvasive peripheral devices.⁵ TAPS has the largest evidence base among these devices, with more than 2000 patients in published studies, and the FDA-cleared device is also indicated for postural and kinetic tremor in Parkinson disease.¹

For clinicians, the results suggest that TAPS’s benefit may not be confined to the stimulation session and that consistent use may matter. The study did not directly compare regular use with as-needed use, though. The BF-ADL gains held among once-daily users, which may help when counseling patients about adherence. The TETRAS changes were modest, below 1 point on a 24-point scale. The larger shifts appeared on the patient-rated BF-ADL, which may be more sensitive to expectation effects.¹

Authors noted that the improvements may partly reflect placebo effects, learning effects, or reduced stress and anxiety as patients grew familiar with study procedures. The analysis was retrospective, included 192 of 263 enrolled patients, and covered only 3 months. ET also progresses at variable rates, which complicates interpretation over longer periods.

The study was funded by Cala Health, the device manufacturer, and several authors are employees, board members, or paid advisers of the company. Investigators called for a long-term, randomized, sham-controlled trial to quantify the underlying effect. They also called for longer studies to determine whether consistent TAPS use alters disease progression.

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REFERENCES
1. Isaacson SH, Peckham E, Tse W, et al. Underlying Tremor Improvement with Consistent Use of Transcutaneous Afferent Patterned Stimulation in Patients with Essential Tremor. Tremor Other Hyperkinet Mov (N Y). 2026;16:1. Published 2026 Jan 9. doi:10.5334/tohm.1091
2.Isaacson SH, Peckham E, Tse W, et al. Prospective Home-use Study on Non-invasive Neuromodulation Therapy for Essential Tremor. Tremor Other Hyperkinet Mov (N Y). 2020;10:29. Published 2020 Aug 14. doi:10.5334/tohm.59
3. Pascual-Valdunciel A, Rajagopal A, Pons JL, Delp S. Non-invasive electrical stimulation of peripheral nerves for the management of tremor. J Neurol Sci. 2022;435:120195. doi:10.1016/j.jns.2022.120195
4. Dash D, Bruno V, Schwingenschuh P, et al. Update on Medical Treatments for Essential Tremor: An International Parkinson and Movement Disorder Society Evidence-Based Medicine Review. Mov Disord. 2026;41(4):815-825. doi:10.1002/mds.70184
5. Adabi K, Ondo WG. Shaking Up Essential Tremor: Peripheral Devices and Mechanical Strategies to Reduce Tremor. Tremor Other Hyperkinet Mov (N Y). 2024;14:55. Published 2024 Nov 11. doi:10.5334/tohm.930