Abstract Details

This pilot study aimed to assess how transcutaneous afferent patterned stimulation (TAPS) affects action hand tremor in people with Essential Tremor (ET) or Parkinson’s disease by examining the temporal dynamics of tremor severity changes and its impact on activities of daily living (ADLs), and identifying the relationship between objective tremor measurement and patient-reported burden during ADLs.

Six participants (5 ET) performed postural tremor tasks and eating, drinking and writing tasks of Bain and Findley ADL (BF-ADL) before and after one 40-min TAPS therapy session in a single in-clinic visit. BF-ADL ratings and tremor power measurements (4-12 Hz band) were collected immediately before (baseline) and after stimulation, and then every 30 minutes for 90 minutes.

Self-reported ratings decreased from baseline in all patients across BF-ADL tasks at all post-stimulation timepoints (mean±SD; baseline, 2.92±0.66; 90mins, 1.61±0.64). Similar reductions in tremor power were observed in 4 patients during postural holds (all patients: geometric mean; baseline, 0.15(m/s²)²; 90mins, 0.01(m/s2)2) and in all patients across BF-ADL tasks (baseline, 0.26(m/s²)²; 90mins, 0.08(m/s²)²). A significant relationship between log₁₀-transformed tremor power and BF-ADL ratings was found (r=0.42, 95% CI [0.26, 0.56], p<0.001).

A single TAPS session can improve tremor and ADL burden for at least 90 minutes, consistent with previous survey findings [Isaacson 2020]. Furthermore, the strong correlation between tremor power and patients’ self-ratings during ADLs suggests that this tremor power metric may accurately represent functional burden in patients with action tremor.