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

Objective: To investigate 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) compared to a criterion standard three-dimensional motion analysis system during a lower limb spasticity assessment. Design: Observational, criterion standard comparison study. Setting: Large rehabilitation centre. Participants: A convenience sample of thirty-five healthy controls, 35 patients with a neurological condition and 34 rehabilitation professionals (physiotherapists and rehabilitation doctors) participated. Interventions: Not applicable. Main Outcome Measure(s): The Modified Tardieu Scale was used to assess spasticity of the the quadriceps, hamstrings, soleus and gastrocnemius. Data for each trial were collected concurrently using the criterion standard Optitrack three-dimensional motion analysis (3DMA) system, Microsoft KinectTM and Smartphone. Each healthy control participant was assessed by one health professional and each patient with a neurological condition was assessed by three health professionals. 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. Overall, 74.8% of the relationships investigated demonstrated a very strong (≥ 0.80) correlation across all of the testing parameters. 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 comparable for measuring total joint ROM. Conclusions: These findings provide preliminary evidence that user-friendly, low-cost technologies can be used to facilitate accurate measurements of joint angular velocity and angles during a lower limb spasticity assessment in a clinical setting