Instrumented shoulder functional assessment using inertial measurement units for frozen shoulder

TL;DR

This study introduces an IMU-based method to objectively assess shoulder function in frozen shoulder patients by analyzing kinematic parameters during specific functional tasks, revealing subtle differences not seen in complete task analysis.

Contribution

The paper presents a novel IMU-based assessment approach that analyzes subtasks of shoulder movements to detect subtle clinical differences in frozen shoulder patients.

Findings

Smoothness features differentiate FS patients from healthy controls

Subtask analysis reveals subtle clinical differences

IMU-based metrics correlate with clinical conditions

Abstract

Frozen shoulder (FS) is a shoulder condition that leads to pain and loss of shoulder range of motion. FS patients have difficulties in independently performing daily activities. Inertial measurement units (IMUs) have been developed to objectively measure upper limb range of motion (ROM) and shoulder function. In this work, we propose an IMU-based shoulder functional task assessment with kinematic parameters (e.g., smoothness, power, speed, and duration) in FS patients and analyze the functional performance on complete shoulder tasks and subtasks. Twenty FS patients and twenty healthy subjects were recruited in this study. Five shoulder functional tasks are performed by participants, such as washing hair (WH), washing upper back (WUB), washing lower back (WLB), placing an object on a high shelf (POH), and removing an object from back pocket (ROP). The results demonstrate that the used smoothness features can reflect the differences of movement fluency between FS patients and healthy controls (p < 0.05 and effect size > 0.8). Moreover, features of subtasks provided subtle information related to clinical conditions that have not been revealed in features of a complete task, especially the defined subtask 1 and 2 of each task.