Accurate clinical spasticity assessment: Validation of movement speed and joint angle assessments using Smartphones and camera tracking.

Abstract

Background: Lower limb spasticity is prevalent following neurological injury, yet its impact on mobility remains unclear. The choice and application of spasticity assessment tools may influence the conflicting findings on the relationship between spasticity and mobility. This study aimed to establish whether a three-dimensional camera (Microsoft KinectTM) and a Smartphone can be used to accurately quantify the joint angular velocity and range of motion (ROM) during a lower limb spasticity assessment. Methods: Thirty-five healthy controls, 35 patients with a neurological condition and 34 rehabilitation professionals participated. Spasticity of the quadriceps, hamstrings, soleus and gastrocnemius were assessed using the Modified Tardieu Scale (MTS). Data for each trial were collected concurrently using the criterion reference Optitrack three-dimensional motion analysis (3DMA) system, Microsoft KinectTM and Smartphone. Joint start angle, end angle, total ROM and peak testing velocity were measured. Spearman’s rho and intraclass correlation coefficients (ICC2,k) with 95% confidence intervals were used to report the strength of the relationships investigated. Results: The Smartphone and Microsoft KinectTM demonstrated excellent concurrent validity with the 3DMA system, with 74.8% of the relationships investigated demonstrating a very strong (≥ 0.80) correlation. The Microsoft KinectTM was superior to the Smartphone for measuring joint start and end angle, the Smartphone superior for measuring joint angular velocity, and the systems were comparable when measuring total joint ROM. Conclusions: There is scope in clinical practice to implement user-friendly and low-cost technologies to provide valid and standardised measures of joint angles and angular velocity when applying the MTS in clinical practice.