Obstacle avoidance in Down syndrome.

Introduction: The ability to avoid obstacles requires to represent the properties of the obstacle, represent the location of the obstacle relative to the body and update these representations as the body moves. Individuals with Down syndrome (DS) often have trouble avoiding obstacles, leading to increased frequency of trips and falling. The aim of the present study was to deeply analyze obstacle avoidance strategies in normally developed young adults (N) and in young adults with DS, at different levels of obstacle heights, with particular attention to the strategies used for clearing the obstacle and to how the walking pattern was modified by obstacle perception.

Methods: 10 DS and 16 age-matched N walked along a walkway in three conditions: plain walking, walking with obstacle at ground level, walking with obstacle at 10% of the subject's height. Spatiotemporal parameters were analyzed.

Results: There was evidence for a different avoidance strategy in DS, and for a difficulty in regulating gait parameters when challenged with a complex situation as the presence of an obstacle. This may lead to an increased risk of fall. The results in addition suggested a lack in anticipatory movement adjustments in DS and provided further evidence of the presence of difficulties in perceptual-motor coupling in DS.