Abstract des Autors

The purpose of this study was to investigate gait control and target pointing parameters during adaptive locomotion under externally controlled visual sampling while manipulating task difficulty. Ten undergraduate students, independent walkers with normal or corrected-to-normal vision, volunteered to participate. Participants walked five meters towards one square target flush to the ground. The task was to point with the forefoot at the center of the target. LCD visual occlusion goggles were used to create three visual conditions based on gait cycle events: full vision, stance vision (vision when the pointing foot was in stance), and swing vision (vision when the pointing foot was in swing). Two target sizes and three visual conditions were presented in a random fashion. Consistent with studies on more dynamic tasks, the results revealed a robust footfall variability pattern during target approach, with the step adjustments spread out over the last steps regardless of experimental conditions which suggest the presence of feed-forward control. The target pointing outcome showed a larger absolute error magnitude as well as increased odds of target overshooting for the small target in the direction of locomotion progression regardless of the visual condition, consistent with the hypothesis. Conversely, the medio-lateral pointing accuracy and consistency decreased if vision was not available during the last swing before target pointing regardless of target size. These results may be used as a basis for quantifying adaptive locomotor tasks in terms of difficulty supporting the design of highly transferable rehabilitation protocols. Verf.-Referat