This study evaluated sustained benefit in underlying tremor baseline at 1 and 3 months in essential tremor (ET) patients using transcutaneous afferent patterned stimulation (TAPS) therapy.
TAPSTM is a prescription wrist-worn neurostimulation therapy that uses frequency-calibrated excitation of the median and radial nerves to reduce tremor in ET (Cala Health, San Mateo, CA, USA). In April 2024, Medicare contractors issued requirements for continued coverage of TAPS based on the Bain & Findley Activities of Daily Living (BF-ADL) improvement in the first 3 months of TAPS usage [L39591]. PROSPECT was a 263-patient study evaluating TAPS used twice-daily for 3 months [Isaacson 2020]. Inclusion criteria required patients to have at least one BF-ADL rated ≥3 at enrollment. The study assessed in-clinic, patient-rated BF-ADL scores at pre- and post-stimulation at enrollment, 1-month, and 3-month visits.
While the pre-specified PROSPECT endpoints evaluated tremor after stimulation, this retrospective analysis used the tremor levels assessed before stimulation to investigate the sustained effect of TAPS on patients’ underlying tremor baseline. The methodology for BF-ADL sustained benefit was aligned to the criteria for continued Medicare coverage, with benefit defined as an improvement of at least 1 point between enrollment and the 1-month or 3-month follow-up visit for a BF-ADL task rated ≥3 at enrollment. Paired t-tests were adjusted for multiple comparisons.
Sustained benefit in BF-ADL score was seen in 84% of patients at month 1, and 85% at month 3. The average improvement in BF-ADL scores for the sum of 8 measured tasks was 2.0±0.3 and 2.7±0.3 points (mean±SE) between enrollment and the 1- or 3-month visit, respectively (both p<0.001). Patients using therapy ≥70% of days in the week before the 3-month visit showed a trend of greater BF-ADL improvement (2.9±0.3) than less frequent users (2.0±0.7).