Upper Extremity Examination for Neuromuscular Diseases (U-EXTEND): Protocol for a Multimodal Feasibility Study

Area of Science:

• Neurology
• Biomedical Engineering
• Rehabilitation Medicine

Background:

• Neuromuscular diseases (e.g., spinal muscular atrophy, Duchenne muscular dystrophy) cause significant motor impairment and can be fatal.
• Current motor scale tests may not capture subtle functional changes, necessitating new evaluation methods.
• Novel treatments are emerging, increasing the need for sensitive outcome measures in clinical trials.

Purpose of the Study:

• To develop and validate a novel, multimodal paradigm for assessing upper extremity motor function in pediatric neuromuscular diseases.
• To create objective, quantitative measures of muscle structure and function beyond current clinical metrics.
• To accelerate the development pipeline for new childhood neuromuscular disease treatments through improved clinical trial endpoints.

Main Methods:

• The Upper Extremity Examination for Neuromuscular Diseases (U-EXTEND) study employs ultrasound imaging and handheld dynamometry to assess muscle size, quality, and function (biceps, pronator).
• Wearable wireless sensor technology captures motion data during activities of daily living.
• Data from participants with SMA and DMD will be compared to a healthy cohort to establish normative values and calculate a motor function score.

Main Results:

• Participant enrollment began in January 2021, with 44 individuals (9 SMA, 20 DMD, 15 healthy) enrolled by July 2022.
• Data collection is ongoing for both ultrasound and sensor-based measurements.
• Initial results were anticipated for publication in summer 2022.

Conclusions:

• The study hypothesizes that the multimodal approach will precisely quantify motor function changes in neuromuscular disease patients.
• This system aims to track the minimal clinically important difference, enabling better assessment of novel treatment efficacy.
• Comparing muscle and functional scores over time will detect subtle improvements in patient function and intrinsic muscle properties.