Objective measurement of synergistic movement patterns of the upper extremity following stroke: an explorative study

The majority of stroke survivors have to cope with deficits in arm function, which is often monitored with subjective clinical scales during stroke rehabilitation. The aim of this study is to examine whether robotic outcome measures obtained during circle drawing are suitable to objectively measure upper extremity function of stroke survivors, especially regarding synergistic movement patterns. Stroke survivors (n = 16) and healthy subjects (n = 20) drew circles, as big and as round as possible, above a table top. Joint angles and positions of the shoulder and elbow were measured. Synergistic movement patterns were identified based on simultaneous changes of the shoulder elevation angle and elbow angle. Stroke survivors moved significantly more within synergistic movement patterns, compared to healthy subjects. Strong correlations between the proximal upper extremity part of the Fugl-Meyer (FM) scale and the use of synergistic movement patterns were found. The proposed outcome measures seem to be suitable measures to objectively quantify the occurrence of synergistic movement patterns of the upper extremity following stroke.