Abstract
During a turn, the body follows a specific motor synergy: the eyes move in the direction of travel followed by the head, trunk, and pelvis. While a number of hypotheses exist on the role of visual information during a walking turn, no one has examined turning behavior in the presence of acute visual deficits of the peripheral and central visual fields. The purpose of the current research was to examine how body segment coordination alters in response to an acute loss of peripheral or central vision during a 90-degree walking turn. Three-dimensional kinematic data of the head, trunk, and pelvis segments were collected on fifteen healthy young adults while they performed a 90-degree walking turn (120 Hz; Vicon, MX). Each participant completed 10 turns in each of three visual conditions created through the use of vision altering glasses: Non-impaired (Control), Peripheral Loss, and Central Loss. Analysis of segment rotations revealed significant differences in head, trunk, and pelvis coordination between the Non-Impaired, Peripheral, and Central Loss conditions (p <0.001). In the Non-Impaired condition, the head moved significantly earlier (520 ms) than the thorax (760 ms) and Pelvis (851ms) respectively (p <0.05). Similarly, during Central Loss, head rotation significantly led trunk rotation (p = 0.043; head 752 ms and trunk 892 ms respectively). However, during Peripheral Loss the head did not lead the trunk significantly, rather significant timing differences were only observed between the head and the pelvis (p = 0.024; head 492 ms and pelvis 750 ms). Therefore, Peripheral Loss was the only visual condition where the head did not precede the trunk, suggesting disruption of the turning motor synergy. These results indicate that visual information derived from the Peripheral field contributes critical information to the Central Nervous System for turning control.
Meeting abstract presented at VSS 2013