Optimizing Transcutaneous Afferent Patterned Stimulation Therapy: Comparison of Variable Waveforms Reveals Increased Responder Rates and Bilateral Tremor Improvement in Essential Tremor
Chiahao Lu1, Samantha Reitmaier1, Alexander Kent1, Kathryn Rosenbluth1
1Cala Health
Objective:
To evaluate the comparative performance of three variations (standard; burst frequency variation, BFV; pulse frequency variation, PFV) of Cala TAPSTM therapy across a multiple-study clinical paradigm in essential tremor (ET) patients.
Background:
Initial patient-level analysis indicates many patients receive greater response to variable TAPS modes than standard TAPS. This report presents findings from clinician-rated scales and bilateral assessments aimed at optimizing stimulation patterns.
Design/Methods:
This report includes data from a series of prospective, randomized studies comparing standard TAPS, BFV-TAPS, and PFV-TAPS in ET patients. Analysis will include a total of 78 patients (28 completed, 50 ongoing) with functionally limiting upper limb tremor enrolled in 6-week studies with 2 weeks on each therapy. Effectiveness was assessed via clinician-rated Tremor Research Group Essential Tremor Rating Assessment Scale (TETRAS) performance subscale and patient-reported Bain and Findley Activities of Daily Living scores. TETRAS assessments were conducted bilaterally pre- and post-stimulation in the completed cohort (N=28), with calculation of mean TETRAS improvement and the proportion of patients achieving benefit (≥1-point improvement).
Results:
Pooled analysis demonstrated that all three TAPS modes produced statistically significant tremor reduction. In the completed cohort (N=28), BFV-TAPS significantly increased the proportion of patients achieving ≥1-point improvement compared with Standard TAPS (89.3% vs. 80.4%, OR=4.6, p=0.049). Furthermore, a bilateral effect on tremor was confirmed by TETRAS, with significant mean improvement on both the stimulated (2.7±0.4) and contralateral (1.3±0.3) sides (p<0.001). Mean TETRAS change was similar across the three modes, and the effect of side was consistent (therapy×side interaction: p=0.551).
Conclusions:
Unilateral TAPS therapy produced bilateral tremor improvement as measured by TETRAS, regardless of the therapy mode. Notably, BFV-TAPS significantly increased the proportion of patients achieving clinician-rated functional benefit (≥1-point improvement). Further research is warranted to clarify the clinical value of bilateral vs unilateral stimulation.
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