Reachable Workspace as a Clinical Outcome for Upper Extremity Function: A Narrative Review

Area of Science:

• Biomedical Engineering
• Clinical Outcome Assessment
• Rehabilitation Technology

Background:

• Upper extremity (UE) impairment affects mobility and function in various diseases.
• Existing assessment methods may lack sensitivity or comprehensive data capture.
• Motion sensing offers a novel approach to quantify UE function.

Purpose of the Study:

• To introduce and validate three-dimensional reachable workspace (RWS) and relative surface area (RSA) as measures of UE function.
• To demonstrate the clinical utility and sensitivity of RWS/RSA in distinguishing healthy from impaired UE function.
• To explore the application of RWS/RSA in various neuromuscular and musculoskeletal conditions.

Main Methods:

• Utilizing motion sensing technology to capture detailed UE motion.
• Reconstructing an individual's 3D reachable workspace (RWS).
• Quantifying RWS as relative surface area (RSA) for functional assessment.

Main Results:

• RSA reliably distinguishes between healthy and impaired UE function.
• RSA demonstrates sensitivity in detecting longitudinal changes, even in slowly progressive conditions.
• RWS/RSA show strong associations with established clinical measures, PROs, and functional performance.

Conclusions:

• Sensor-based RWS is a valid, reliable, and sensitive UE clinical outcome assessment (COA) tool.
• RWS/RSA have demonstrated clinical utility in neuromuscular diseases (FSHD, DMD, ALS) and other conditions (stroke, orthopedic).
• Future integration of mobile sensing, AI, and machine learning promises enhanced clinical studies and patient care.