Remote assessment of action tremors during COVID-19: A pooled meta-analysis of transcutaneous afferent patterned stimulation in Parkinson’s Disease and Essential Tremor
Ruta Deshpande1, Samuel Hamner1, Apoorva Rajagopal1, Kate Rosenbluth1, Dhira Khosla1,2
1Cala Health, Inc., 2Personal Care Neurology
To compare action tremor assessed in-person, remotely by telemedicine, and remotely using objective motion-sensor data.
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.
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.

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)).

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.