To develop and validate digital monitoring biomarkers for tracking changes in upper and lower limb function in Inclusion Body Myositis (IBM) over time.

IBM results in physical disability due to relentlessly progressive muscle weakness. There is no effective therapy to change the disease trajectory. Assessment of function is quantified in IBM clinical care and research using a combination of physician-assessed scales for muscle strength, as well as the IBM Functional Rating Scale (IBMFRS).

Our study design involves a 24-month prospective clinical study, focusing on recruiting 20 IBM patients. Participants will undergo baseline assessments and return every 6 months for 24 months. The IBMFRS, strength assessments, and patient-reported outcomes are assessed during each visit. Participants are given a PAMSys^TM pendant and 2 PAMSys ULM^TM wrist sensors for at-home monitoring of physical activity, posture, and upper limb function for 7 consecutive days.

Eleven participants have been enrolled. An interim analysis of the first 10 participants (mean age 69.7 ± 7.6 years, 7 female) show that sensor-derived measures of physical activity collected after the baseline visit have significant correlation with the lower extremity subdomain score of the IBMFRS (items 7-10) with correlations ranging from r = -0.558 to -0.846 (p < 0.05). Similarly, sensor-derived measures of hand function collected after the baseline demonstrated moderate to strong correlations with the upper extremity subdomain score of the IBMFRS, with correlations between r = 0.649 and 0.775.

While full study results are pending, the interim analysis of the baseline data indicate that wearable-based monitoring at home has the potential to track motor dysfunction in IBM effectively. Such digitized assessments provide objective data, improve compliance, increase convenience, and offer scalability and cost-effectiveness, thereby advancing clinical care and research in IBM.