Stroke Affects the Coordination of Gaze and Posture During Preplanned Turns While Walking

Abstract

Background In healthy subjects, the act of walking and turning is accomplished by a sequential horizontal reorientation of gaze, head, and body toward the direction of the turn. Subjects with stroke, however, have difficulty altering their walking direction and present with loss of balance when performing a head turn or whole body rotation. Objective. To study, in a pilot case study, the spatial and temporal coordination of gaze and posture during preplanned turns executed while walking in severely disabled and mildly disabled subjects with stroke as compared to a healthy control walking at slow speed. Methods. Horizontal plane orientations of gaze, head, thorax, pelvis, and feet as well as the body’s center of mass (CoM) trajectory were analyzed as subjects were walking straight or executing a 90-deg turn. Results. Subjects with stroke revealed altered orientation and sequencing of gaze body segments. These alterations were more pronounced in the most severely disabled subject with stroke, especially when turning to the nonparetic side as compared to the paretic side. Conclusions. These findings suggest an altered coordination of gaze and posture during steering of locomotion in subjects with stroke. This altered coordination is likely due to a complex interaction of motor, sensory, and biomechanical factors that may explain the poor balance and poor control of heading direction during walking and turning in stroke.