Objective:

This analysis aimed to expand understanding of the efficacy and safety of consecutive transcutaneous afferent patterned stimulation (TAPS) sessions in people with essential tremor (ET) or Parkinson's Disease (PD).

Background:

TAPS is a non-invasive neuromodulation therapy that can improve action tremor in people with ET or PD [Isaacson 2020]. While real world evidence has demonstrated that tremor improvement can persist over back-to-back (i.e. consecutive) sessions in real-world settings [Lu 2023], this has yet to be evaluated in a prospective study.

Design/Methods:

Eleven ET and 9 PD patients were instructed to perform 3 daily back-to-back 40-minute TAPS sessions at home for 2 weeks. Back-to-back sessions were defined as those that were at least 20 minutes in length and within 20 minutes of one another. Measures of tremor power were collected on-device before and after every session during remote patient visits. The tremor power improvement ratio (pre/post-stimulation power, TPIR) of each session was computed by comparing post-stimulation power to the pre-stimulation power of the first session. Median TPIR was then calculated for each patient. 

Results:

Of the 20 enrolled patients, 16 (8 ET, 8 PD) completed the study. Tremor power improved after the first TAPS session (3.00 ×/÷ 1.54, geometric mean and standard error), was maintained at a similar level after the second session (3.05 ×/÷ 1.56, p=0.782) and may have increased after the third session (9.34 ×/÷ 1.97, uncorrected p=0.039). Ten percent (2 out of 20) patients reported an adverse event of which both were for minor skin irritation.

Conclusions:

These findings suggest that patients could perform consecutive therapy sessions to experience longer action hand tremor relief and that back-to-back sessions share a similar safety profile to that of a single TAPS session [Isaacson 2020]. Future work is warranted to identify the patient population that is most likely to benefit from consecutive sessions.