TAPS is a FDA-cleared, non-invasive, wrist-worn therapy for hand tremor in Essential Tremor (ET) also granted Breakthrough Designation for action tremor in Parkinson’s disease (PD). The most prevalent adverse event of TAPS therapy is dorsal wrist skin irritation.

Finite element modeling suggested a 6-electrode configuration provided similar median and radial nerve excitation with lower stimulation amplitudes than standard TAPS 3-electrode configuration. Nineteen action tremor subjects with ET or PD were enrolled in a study comparing telemedicine clinical ratings (TETRAS or UPDRS), activities of daily living (BF-ADL), and motion sensor data (tremor power improvement ratio, TPIR) over two weeks of home-use per configuration.

Mean stimulation amplitude was reduced from 4.0mA to 2.7mA from 3- to 6-electrodes, respectively (p=0.0001). Adverse events (e.g., skin irritation) were 71% (5 of 7) and 29% (2 of 7) with 3- and 6-electrodes (p=0.3).

Efficacy was similar between electrode configurations. Median TPIR was 2.2 (IQR: 1.2-4.3) and 2.2 (1.2-2.7) for 3- and 6-electrodes (p<0.0001 per configuration, p=0.3 between configurations). Responder analysis showed 87% improved (TPIR>1) with both configurations, while 53% and 60% improved 2-fold (TPIR>2) for 3- and 6-electrodes. Mean BF-ADL improved 0.5 (SD: 0.3) and 0.5 (0.6) with 3- and 6-electrodes (p=1.0), while mean TETRAS improved 0.4 (0.3) and 0.4 (0.5) (p=0.8, N=10) and mean UPDRS improved 0.9 (0.6) and 0.6 (0.2) respectively (N=6).