Upper EXTremity Examination for Neuromuscular Diseases (U-EXTEND): A protocol for a feasibility study to explore the use of wearable sensors and ultrasound techniques to develop novel measures for muscle function (Preprint)

BACKGROUND Neuromuscular diseases, such as Spinal Muscular Atrophy (SMA) and Duchenne Muscular Dystrophy (DMD), may lead to loss of motor movements, respiratory failure, and early mortality in young children and adulthood. With novel treatments now available, new evaluation methods are needed to assess progress not currently captured with existing motor scale tests. OBJECTIVE With this feasibility study, our interdisciplinary team of investigators aims to develop a novel, multi-modal paradigm of measuring motor function in children with neuromuscular diseases that will revolutionize the way clinical trial endpoints are measured moving forward, therefore accelerating the pipeline of new treatments for childhood neuromuscular diseases. Through the Upper EXTremity Examination for Neuromuscular Diseases (U-EXTEND), we hypothesize that the novel objective measures of upper extremity muscle structure and function proposed here will be able to distinguish small changes and differences in function that are not measurable by current clinical metrics. METHODS U-EXTEND introduces a novel paradigm using concrete, quantitative measures to assess motor function in patients with SMA and DMD. Aim 1 will focus on the use of ultrasound techniques to study muscle size, quality, and function, specifically isolating the biceps and pronator muscles of the upper extremity to follow over time. To achieve this, clinical investigators will extract a set of measurements related to muscle structure, quality, and function using ultrasound imaging and handheld dynamometry. Aim 2 will leverage wearable wireless sensor technology to capture motion data as subjects perform activities of daily living. Measurement data will be examined and compared to a healthy cohort, while providing a motor function score. RESULTS U-EXTEND data collection began in January 2020, and we anticipate preliminary results will be available in Summer 2022. CONCLUSIONS U-EXTEND is poised to make a valuable contribution to the neuromuscular disease community, clinical trial design, ubiquitous computing technologies, and skeletal muscle ultrasound imaging. We are especially eager to explore the ability of U-EXTEND to support clinical outcomes, and to provide clarity in patient motor function ability in neuromuscular disorders, and extending to a wide variety of neuromotor challenges.