Community-dwelling people with chronic stroke need disproportionate attention while walking and negotiating obstacles

The objective of the present study was to examine the attentional demands of gait adaptations required to walk over irregular terrain in community-dwelling people with chronic stroke. Eight community ambulators (>6 months post-stroke, aged 57 ± 15 years) and eight age-matched healthy controls participated in the study. As the primary motor task, participants walked on a treadmill while they quickly reacted to a sudden obstacle in front of the affected (in the stroke group) or left (in healthy controls) leg. The secondary, cognitive task was an auditory Stroop task. Outcomes were avoidance success rate and muscle reaction times of the biceps and rectus femoris (motor task), and a composite score of accuracy and verbal reaction time (cognitive task). Success rates did not differ between single- and dual-task conditions in either group, while muscle reaction times deteriorated equally during the dual task in both groups. However, compared with the Stroop scores just before and after obstacle crossing, the scores while crossing the obstacle deteriorated more in the stroke group than in the controls (p=0.012). The higher dual-task costs on the Stroop task reflect greater attentional demands during walking and crossing obstacles. The absence of dual-task effects on obstacle avoidance performance suggests that the people with stroke used a "posture-first strategy". The results imply that common daily life tasks such as obstacle crossing while walking require disproportionate attention even in well-recovered people with stroke.