Shoulder Motion Evaluation in Patients with Cervical Spinal Cord Injury via Inertial Measurement Unit- based System

In an attempt to achieve functional independence of individuals with cervical spinal cord injury (CSCI), several rehabilitation programs or surgical interventions have been developed to restore shoulder range of motion (ROM). In clinical settings the gold standard for measuring joint ROM in patients with CSCI is the goniometer, a portable, inexpensive, quasi-objective tool. However, the need for more objective methods when evaluating motor parameters appears to be of great importance. The aim of the study was to test the validity of a wearable Inertial Measurement Unit (IMU) sensor system by comparing the accuracy of the IMU system to goniometer method in measuring shoulder ROM. Eight participants with CSCI completed four shoulder movements (forward flexion, abduction, and internal and external rotation) on dominant shoulder. Each movement was assessed with a goniometer and the IMU system by two testers independently. The extent of agreement between each tester’s goniometer and IMU measurements was assessed with intra-class correlation coefficients (ICC) and Bland-Altman 95% limits of agreement (LOA). Additional analysis compared agreement between tester’s goniometer or IMU measurements (inter-rater reliability) using ICC’s and LOA. Preliminary results showed that goniometer and IMU measurements had excellent levels of agreement for all tested movements; however, LOAs were found high. Inter-rater reliability was found excellent between the IMUs measurements, while it was found lower between tester’s goniometer. LOAs were found high also when agreement between tester’s goniometer or IMU measurements were compared. The current study provides preliminary evidence of the concurrent validity of a wearable IMU sensor system for assessing shoulder movements in patients with cervical spinal cord injury. This can be a potential monitoring and clinical diagnostic tool to be widely used in clinical settings at the service of specialized personnel supporting spinal cord injured subjects.