Eye-head coordination during overground locomotion and avoidance of virtual pedestrians

• Published in: International Conference on Virtual Rehabilitation (Print) pp. 1 - 2
• Main Authors: Boulanger, M., Lamontagne, A.
• Format: Conference Proceeding
• Language: English
• Published: IEEE 01.06.2017
• Subjects: Avatars; Collision avoidance; Eye-head coordination; Legged locomotion; locomotion; Magnetic heads; obstacle avoidance; Trajectory; virtual environment; Virtual environments; Visualization
• ISSN: 2331-9569
• DOI: 10.1109/ICVR.2017.8007536

Background: Avoiding collisions with other pedestrians during overground locomotion is a trivial task for young adults, but with age or for stroke survivors it can become a daunting endeavour. Coordinated eye-head movements probably play an important role in obstacle circumvention, but unfortunately the literature on the subject is rather scarce. Objectives: The aim of this study was therefore to investigate eye-head coordination during overground locomotion, and, more specifically, during avoidance of dynamic virtual pedestrians. Methods: We recorded eye (ASL eyetracker ) and body (Vicon system) movements in five healthy young adults during overground locomotion as they navigated in a virtual environment visualized in a helmet mounted display. Medio-lateral (ML) displacements as well as the pattern of eye, head and gaze reorientation in the horizontal plane were examined. Participants were instructed to walk toward a goal represented by a blue target located 9.5m straight ahead and to avoid a non-reactive human-like avatar coming from different angles of approach. Results: We found that ML trajectory displacements were preceded by a head rotation in the direction of veering. Halfway through the ML head displacement, a head rotation in the direction opposite to that of the ML displacement was observed. Head rotations were themselves preceded by eye saccade(s) toward the side of circumvention. During the circumvention, no attempt was made to keep the head in alignment with the goal. Conclusions: Eye/gaze movements appear to play an important role during the avoidance of dynamic obstacles while walking. Eye movements are initiated ahead of the trajectory ML displacement, possibly to localize the obstacle and/or plan the future walking trajectory.