Technical Properties of a Sensor-Aided Key Rig for Hand Function Measurement: A Proof of Concept Study

Objective quantification of hand functions using sensorized devices has gained recognition lately in clinical practice. Traditional clinical assessment scales lack precision and quantifiability, prompting the exploration of new methodologies. The following work focuses on the design, development, and testing of a sensorized key rig that can be used to perform quantifiable metrics of hand functions. Leveraging advancements in sensor technology, the study developed an instrumented key rig equipped with an off-center load cell for accurate pinch force measurement. In addition, a magnetic rotary encoder was added to track the key-turning movement. Calibration and testing procedures ensured the rig’s reliability and repeatability. Results demonstrated consistent and precise measurements with the reliability intraclass correlation coefficient (ICC) of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${p} \,\, =0.99996$ </tex-math></inline-formula>, highlighting the key-rig device potential for clinical motor function assessment and rehabilitation monitoring. Further research could explore its comparative effectiveness and clinical applications with stroke survivors.