Visuospatial neglect (VSN) impairs the control of locomotor heading in post-stroke individuals, which may affect their ability to safely avoid moving objects while walking.
We aimed to compare VSN+ and VSN− stroke individuals in terms of changes in heading and head orientation in space while avoiding obstacles approaching from different directions and reorienting toward the final target.
Stroke participants with VSN (VSN+) and without VSN (VSN−) walked in a virtual environment avoiding obstacles that approached contralesionally, head-on or ipsilesionally. Measures of obstacle avoidance (onset-of-heading change, maximum mediolateral deviation) and target alignment (heading and head-rotation errors with respect to target) were compared across groups and obstacle directions.
In total, 26 participants with right-hemisphere stroke participated (13 VSN+ and 13 VSN−; 24 males; mean age 60.3 years, range 48 to 72 years). A larger proportion of VSN+ (75%) than VSN− (38%) participants collided with contralesional and head-on obstacles. For VSN− participants, deviating to the same side as the obstacle was a safe strategy to avoid diagonal obstacles and deviating to the opposite-side led to occasional collisions. VSN+ participants deviated ipsilesionally, displaying same-side and opposite-side strategies for ipsilesional and contralesional obstacles, respectively. Overall, VSN+ participants showed greater distances at onset-of-heading change, smaller maximum mediolateral deviation and larger errors in target alignment as compared with VSN− participants.
The ipsilesional bias arising from VSN influences the modulation of heading in response to obstacles and, along with the adoption of the “riskier” strategies, contribute to the higher number colliders and poor goal-directed walking abilities in stroke survivors with VSN. Future research should focus on developing assessment and training tools for complex locomotor tasks such as obstacle avoidance in this population.Le texte complet de cet article est disponible en PDF.
Keywords : Visual neglect, Cerebrovascular accident, Steering, Obstacle circumvention, Virtual Reality