Remote assessment of action tremors during COVID-19: A pooled meta-analysis of transcutaneous afferent patterned stimulation in Parkinson's disease and essential tremor

Objective: To compare action tremor assessed in-person, remotely by telemedicine, and remotely using objective motion-sensor data. Background: Access to clinical care has become more difficult for patients living with chronic diseases such as Essential Tremor (ET) and Parkinson's Disease (PD), due to COVID-19. This meta-analysis compared studies using in-person or telemedicine clinical appointments along with motion-sensor measurements to assess the therapeutic benefit of Transcutaneous Afferent Patterned Stimulation (TAPS) [Pahwa R. et al., 2019] for action tremor (i.e., tremor elicited by voluntary muscle contraction, including postural and kinetic tremors) in ET and PD patients. Design/Methods: De-identified tremor motion data were compared across three cohorts receiving TAPS therapy under clinical supervision: (1) ET action tremor assessed in-person and remotely (N=193;3-month motion-sensor remote assessment with 3 in-person visits);(2) PD action tremor assessed in-person (N=11;5 in-person visits), and (3) PD action tremor assessed remotely (telemedicine visits over 1-month;currently enrolling). The pooled analysis compared (i) sensor-measured improvements in tremor severity with TAPS therapy, and (ii) correlation between clinician-rated and sensor-measured assessments of tremor severity. Results: ET patients experienced a median 42% reduction in tremor severity in-clinic and 53% reduction in tremor severity at home (study 1) [Isaacson S. et al., 2020]. PD patients experienced a median 38% reduction in tremor severity (study 2). Sensor-measured reductions in severity were consistent across patient cohorts (p=0.3, PD vs ET in-person), but different across assessment locations (p<0.01, ET in-person vs ET remote). Clinical gold-standard ratings of tremor severity were correlated with simultaneously-measured sensor assessments (r=0.67 (study 1)1;0.89 (study 2)). Conclusions: These findings provide consistent measures of action tremor reduction from TAPS therapy in PD and ET and suggest that occasional, in-person assessments may not always capture daily at-home improvements;and demonstrate how wearable sensors can be incorporated into remote clinical studies via telemedicine for patients with movement disorders.