Clinical Benefit of Transcutaneous Afferent Patterned Stimulation in Essential Tremor Patients with High Unmet Need
Rajesh Pahwa1, Stuart Isaacson2, Salima Brillman3, Chiahao Lu4, Alexander Kent4
1University of Kansas Medical Center, 2Parkinson's Dis & Mov Dis Ctr of Boca Raton, 3Parkinson's Disease and Movement Disorders Center of Silicon Valley, 4Cala Health
Objective:
This analysis established clinically assessable criteria to identify a high unmet need essential tremor (ET) subgroup and an early responder cohort, and evaluated the response to transcutaneous afferent patterned stimulation (TAPS) in ET patients with high unmet need and early responders.
Background:
TAPS is a non-invasive neuromodulation therapy that improves hand tremor in patients with ET. While prior research demonstrated the safety and efficacy of TAPS, not all patients experience tremor reduction. This analysis can assist healthcare providers in identifying patients who will benefit from TAPS.
Design/Methods:
Literature was surveyed for TAPS studies to assess the clinical response in the high unmet need subgroup (high tremor severity, non-responsive to tremor medication, age≥65 years) and an early responder cohort (substantial TAPS tremor improvement and usage in the first month). Secondary analyses were performed for these patients using previously collected Tremor Research Group Essential Tremor Rating Scale (TETRAS) scores, Bain & Findley activities of daily living (BF-ADL) scores, and measures of tremor power.
Results:
Three studies from literature collected the required data and were included in this analysis [Pahwa 2019, Isaacson 2020, Lu 2023]. Significant differences in BF-ADL and TETRAS improvement were observed with TAPS over sham for the high unmet need subgroup in a randomized controlled study (N=47, p<0.03). During a 3-month open-label study, the high unmet need subgroup (N=138) and early responder cohort (N=51) showed significant improvements in BF-ADL, TETRAS, and tremor power (p<0.001). Secondary analysis of previously published real-world evidence demonstrated that early responders maintained consistent effectiveness and usage at 3 months (N=191, p<0.001) and 12 months (N=76, p<0.001).
Conclusions:
TAPS showed comparable improvements in ET with high unmet need as reported in the original studies, and greater efficacy in early responders. These findings could inform patient selection and the trial process for identifying TAPS therapy responders.