Three-dimensional kinematics of shoulder function in stroke patients: Inter- and intra-rater reliability

Background: It is important to monitor progress during rehabilitation of stroke patients. To that end, clinical function tests may be supported by three-dimensional kinematic measures. The aim of this study was to evaluate the inter- and intra-rater reliability of three-dimensional kinematic measures of shoulder movements in stroke patients with reduced shoulder function. Methods: Seventeen patients were tested in three sessions by two trained raters. Three-dimensional motion capture was performed of the more affected upper extremity and the trunk. Measures of movements of the scapula and humerus related to the trunk, the trunk related to the laboratory, the forearm related to the humerus, and temporospatial measures were obtained during two reach tasks from the Wolf Motor Function Test, ReachLow and ReachHigh. Inter-and intra-rater reliability was quantified with intraclass correlation coefficients (ICC). Findings: In general, range of movements of scapula, shoulder, trunk and elbow and movement time and reach length showed high inter-rater reliability (ICC infinity 0.84-0.98) and intra-rater reliability (ICC infinity 0.75-1.00), A minimum of five trials per task were required to achieve reliable ICC estimates. Interpretation: Selected three-dimensional kinematic measures can be used reliably to evaluate specific movements of the shoulder in stroke patients with reduced shoulder function.