Transcutaneous Afferent Patterned Stimulation Shows Effective Outcomes in Essential Tremor


Cala Health's transcutaneous afferent patterned stimulation demonstrated significant efficacy in patients with essential tremor, as evidenced by positive outcomes in multiple clinical studies.

Kate Rosenbluth, PhD, copresident and chief scientific officer at Cala Health

Kate Rosenbluth, PhD

According to a new announcement from Cala Health, results from multiple clinical studies showed effective outcomes in patients with essential tremor (ET) using the company’s transcutaneous afferent patterned stimulation (TAPS), a noninvasive therapy delivering calibrated stimulation to the median and radial nerves.1 The findings from these trials further strengthen the evidence of using TAPS as an effective therapy for patients with ET to reduce tremors.

The company’s TAPS is performed by using the Cala kIQ device, which is indicated to aid in the temporary relief of hand tremors in the treated hand following stimulation in adults with essential tremor. Also, the device is indicated to aid in the temporary relief of postural and kinetic hand tremor symptoms that impact some activities of daily living in the treated hand following stimulation in adults with Parkinson disease.

Top Clinical Takeaways

  • Cala Health's TAPS therapy has demonstrated effectiveness in reducing tremors for essential tremor patients, offering a promising noninvasive treatment option.
  • Results from a retrospective post-market analysis revealed sustained tremor improvement and safety in a larger population, supporting the long-term viability of TAPS.
  • TAPS shows comparable improvements in essential tremor, particularly in high unmet need subgroups and early responders, influencing patient selection and trial processes.

"We are excited about the growing body of evidence demonstrating that TAPS improves patient outcomes in real-world settings," Kate Rosenbluth, PhD, copresident and chief scientific officer at Cala Health, said in a statement.1 "With these latest publications, TAPS has now been assessed in nearly 2000 [patients with] ET and with use extending beyond 3 years. TAPS addresses the large treatment gap between medications and surgery for ET patients struggling with activities of daily living such as eating, drinking writing and self-care."

A randomized pragmatic trial (NCT05540626) published in Tremor and Other Hyperkinetic Movements met both the primary end point and secondary end point in assessment of TAPS in patients with ET compared with standard of care (SOC) over 1 month of home use. These findings suggest that the TAPS therapy is a safe and valuable treatment option for patients with ET.2

Lead author Dingwei Dai, MD, PhD, lead data scientist at CVS Clinical Trial Services LLC., and colleagues recruited 310 patients who were randomized 1:1 to 1 month of treatment with TAPS or SOC. The primary endpoint was changes in tremor power measured by motion sensors and the secondary endpoints were improvement in Bain & Findley Activities of Daily Living (BF-ADL) upper limb scores reported between TAPS and SOC at one month.

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Overall, 276 patients completed the 1-month end points (TAPS, n = 133; SOC, n = 143). Among these patients, investigators observed a significant reduction of tremor power in TAPS compared with SOC (geometric mean, 0.017 m/s2 [SE, 0.003] vs 0.08 m/s2 [SE, 0.014]; P <.0001) and greater improvement in the BF-ADL score in TAPS than SOC (geometric mean, 1.6 points (SE, 0.43) vs 0.2 points (SE, 0.37); P <.05).2 Approximately 82% of patients using TAPS experienced tremor improvement from before to after therapy. Notably, no serious device-related adverse events were reported in the trial.

A retrospective post-market analysis also published in Tremor and Other Hyperkinetic Movements revealed real-world effectiveness and safety of TAPS beyond a 90-day trial period.3 Lead author Chiahao, Lu, MS, PhD, clinical research scientist at Cala Health, and colleagues screened a manufacturer’s database for TAPS devices prescribed for ET and used beyond a 90-day trial period between August 2019 and January 2023. Device logs collected the therapy usage, accelerometry measurements, and onboard ratings of tremor improvement. Lu and colleagues also assessed the findings of a voluntary survey after the 90-day trial period.

The therapy was between 90 and 1233 days among 1223 participants, with an average usage of 5.6 sessions per week. Further data showed that 89% of patients experienced tremor improvement with an average of 64% improvement, and 63% of patients rated at least half of their sessions as improved. Notably, investigators did not observe a significant habituation in patients who used therapy for more than 1 year. Approximately 62% of respondents either had reduced treatment or planned to consult clinicians about their usage with the treatment. Researchers had no serious safety events reported but 10% of patients reported minor safety complaints.

A secondary analysis in Expert Review of Medical Devices of TAPS showed comparable improvements in ET with high unmet need as reported in the original studies, and greater efficacy in early responders. These findings help to inform patient selection and the trial process for identifying potential TAPS responders.4

Conducted by lead author Stuart H. Isaacson, MD, FAAN, director of the Parkinson’s Disease & Movement Disorders Center at Boca Raton, in Florida, and colleagues, literature was surveyed for TAPS studies to analyze the response in the high unmet need subgroup and early responders. The investigators analyzed the data using previously collected Tremor Research Group Essential Tremor Rating Scale (TETRAS) scores, BF-ADL scores, and tremor power.

Investigators observed significant differences in BF-ADL and TETRAS improvement with TAPS over sham for the high unmet need subgroup in a randomized controlled study (P <.03). During a 3-month open-label study, significant improvements in BF-ADL, TETRAS, and tremor power were observed in the high unmet need subgroup and early responders (P <.001). Analysis of previous real-world evidence showed early responders sustained effectiveness and usage at 3 and 12 months (P <.001).

"Cala is a contracted provider with major national and regional health plans for ET including both commercial and Medicare Advantage members," Deanna Harshbarger, copresident and chief product officer at Cala Health, said in a statement.1 "The Cala System is covered by the Veterans Affairs (VA) Health System at no cost to VA beneficiaries. With these expanded publications, Cala will continue working tirelessly on behalf of patients with ET to secure additional coverage and reimbursement."

1. Cala Announces Data from Multiple Clinical Studies Demonstrating Effective Outcomes of Transcutaneous Afferent Patterned Stimulation (TAPS) Therapy in Essential Tremor (ET). News Release. Cala Health. Published January 9, 2024. Accessed January 12, 2024.
2. Dai D, Fernandes J, Kim H, Coetzer H. Comparative Effectiveness of Transcutaneous Afferent Patterned Stimulation Therapy for Essential Tremor: A Randomized Pragmatic Clinical Trial. Tremor and Other Hyperkinetic Movements. 2023;13(1):38.DOI:
3. Lu C, Khosla D, Kent A, Bronte-Stewart HM, Rosenbluth KH. Transcutaneous Afferent Patterned Stimulation for Essential Tremor: Real-World Evidence with Long Term Follow-Up. Tremor and Other Hyperkinetic Movements. 2023;13(1):29.DOI:
4. Isaacson SH, Pahwa R, Brillman S, Lu C, Kent AR. Clinical benefit of transcutaneous afferent patterned stimulation (TAPS) in essential tremor patients with high unmet need: a secondary analysis of TAPS studies. Expert Rev Med Devices. 2023;20(12):1211-1218. doi:10.1080/17434440.2023.2274604
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