CHICAGO — Personalized waveform settings in a wearable transcutaneous afferent patterned stimulation (TAPS; Cala kIQ Plus) device were associated with higher responder rates in essential tremor (ET) than in standard single-waveform settings, new research showed.

The findings involve a newly cleared version of the noninvasive, wearable TAPS device that allows for customizable stimulation patterns.

The research included two related studies — an initial exploratory trial and a larger validation study — evaluating three stimulation modes of the device: standard TAPS calibrated to tremor frequency, pulse frequency variation, and burst frequency variation.

In the exploratory study, all three stimulation modes produced significant improvements on a tremor rating scale, with reductions observed on both the ipsilateral (stimulated) and contralateral (unstimulated) sides.

In the validation study, all modes again provided acute tremor relief. However, the variable waveform settings — pulse frequency variation and burst frequency variation — were associated with higher responder rates than the standard single-waveform setting, with burst frequency variation showing the greatest benefit. 

Overall, the findings suggest that personalized, variable stimulation patterns may improve daily functioning compared with a fixed waveform, said study co-investigator Alex Kent, PhD, vice president of research at Cala Health, San Mateo, California. 

“Personalization drove enhanced outcomes,” Kent told Medscape Medical News. “For a majority of patients, those two additional forms of TAPS were preferred in terms of providing satisfaction for obtaining tremor relief,” he added.

The studies were presented on April 20 at the American Academy of Neurology (AAN) 2026 Annual Meeting.

‘Next Generation’ Therapy

TAPS therapy delivers alternating electrical pulses to peripheral nerves, with the original system calibrated to each patient’s tremor frequency. In 2018, the FDA cleared it for the treatment of hand symptoms in ET. Introduced in 2023, the Cala kIQ system features a wrist-worn device worn on one hand. 

In a study presented at the International Congress of Parkinson’s Disease and Movement Disorders (MDS) 2025, PET imaging showed that 90 days of use with the Cala TAPS device was associated with significant changes in metabolic activity in key areas of the brain’s tremor circuitry. Specifically, increased activity was observed in the ipsilateral areas of the cerebellum and diencephalon.

Earlier this year, the FDA cleared the Cala kIQ Plus, an updated version of the device that offers three customizable therapy modes. The original version operated with a single mode.

“This is a next-generation device that allows patients to select and try different TAPS therapy modes to determine what works best for them in improving tremor relief,” Kent said. 

In the exploratory crossover study, 30 patients with ET were enrolled and randomly assigned to use each of the three stimulation modes at home, as needed, for 2 weeks each. These included standard TAPS calibrated to a single tremor frequency (mode A), pulse frequency variation at 100 Hz (mode B), and burst frequency variation at 3.2 Hz (mode C). Outcomes included the 5-item clinician-rated Tremor Research Group Essential Tremor Rating Assessment Scale (TETRAS) performance subscale. 

All three modes were associated with improved tremor relief, defined as a ≥ 1-point reduction in TETRAS score. A higher proportion of participants receiving mode C achieved improvement compared with mode A (89.3% vs 80.4%), with significantly greater odds of response (odds ratio, 4.6; P < .05).

There was also significant tremor reduction from baseline on both the ipsilateral and contralateral sides in pooled mode analysis (P < .001). Not surprisingly, the ipsilateral/stimulated side had greater improvement than the contralateral side. 

It was this study that led to the FDA clearance.

Improved Daily Function

The second study, which was completed in March, was a validation randomized crossover trial that enrolled 46 patients with ET.

The primary endpoint was patient-rated improvement on the Bain and Findley Activities of Daily Living (BF-ADL) scale, which assesses tasks such as pouring from a glass, raising a spoon while eating, and writing.

Results showed that although significant improvement was achieved by all three options, mode B was rated significantly better than mode A (P = .01), and mode C was rated better than A (P < .001). Results comparing modes B and C were not reported. 

Additionally, a patient’s personalized “best” mode — based on satisfaction and comfort — was associated with greater improvement on the BF-ADL than the standard mode (P = .002), and 72% of patients preferred the newer therapy modes over the standard setting.

Kent said that while traditional TAPS is already an effective, well-established therapy for many patients, the newer approach expands the range of treatment options available.

“By enabling this additional personalization, patients will be able to test out what works best for them, and I think the likelihood that they’ll be satisfied with TAPS has been increased,” he said. 

Promising Findings

Justin Martello, MD, movement disorders specialist and chief of neurology at MedStar Health in Baltimore, told Medscape Medical News that he was not particularly impressed with the original TAPS technology.

However, he said the findings from the current study are more compelling, noting that the updated approach appears promising and is likely more effective than the earlier version. 

Martello, who was not involved in the research, added that prior experience with deep brain stimulation (DBS) suggests that varying stimulation frequencies may be necessary for optimal treatment of ET, rather than relying on a single, uniform frequency.

He noted that experience with DBS has shown that varying stimulation frequencies are likely needed for effective treatment of ET, “and not just a standard, across-the-board” frequency. 

“So from a science perspective, this makes sense,” he said. He added that, although a direct comparison between the pulse frequency and burst frequency modes would be informative, the key takeaway is that incorporating variability in stimulation appears to be key.

Martello added that an “impressive” part of the study was that efficacy was shown on the contralateral as well as the ipsilateral sides.

“We know through DBS studies that there can be crossover improvement, although not as robust as on the ipsilateral side. So we’re learning more about the communication across the body with these targets,” he said.

The study was funded by Cala Health, and Kent is an employee of the company. Martello reported having no relevant financial relationships.