Objectively Characterized Linear Model of Stroke Induced Joint Synergies in Relation to Clinical Measures

Abstract

Subjective kinematic motion analysis done by a trained physical therapist using standard assessment such as the Fugl-Meyer assessment (FM) and/or theWolf Motor Function test (Wolf), have a limited ability to objectively characterize post stroke movement of subjects with a hemiparetic limb or demonstrate fine change over time. The goal of the research was to take the characterized synergies linear matrix model and find an application with stroke survivors. Twenty-two participants were tested for motor impairment using a modified FM (MFM) assessment. Motion capture data was collected using the Vicon motion capture system. This data was processed using Vicon BodyBuilder and MATLAB to construct a stroke subject's Synergy Matrix (SM) from which was developed the Synergy Matrix Score (SMS). This score is compared with the MFM score in terms of efficacy of accepted assessment standards, precise quantitative data, sufficient sensitivity to characterize change over time, and usefulness for clinical reporting. The results show that the SMS provides comparable accurate assessment of the subjects post stroke motion with a high level of sensitivity and greater description of shoulder, elbow, and wrist information in the form of a seven by seven matrix. The SM scoring scale (0,inf) also has the ability to quantify change over time at a finer resolution than the MFM range of 0-2 (33% banding) or the Wolf range of 0-4 (25% banding). Results also show that the SMS objectively generates a relevant score comparable to the MFM while maintaining a greater resolution of detail and density of information allowing the physical therapist to better target therapies as well as spend more time working with patients and less time spent on documentation. Adding the SMS to a control system on a therapeutic robot will further automate the SMS into a realtime feedback loop as applied, for example, to stroke prognosis of the targeted therapy.