Interference between balance, gait and cognitive task performance among people with stroke living in the community.

PURPOSE: To explore differences in cognitive-motor interference between people with stroke and controls when performing functional tasks and to compare dual task performance of stroke fallers and non-fallers.
METHOD: Thirty-six people with stroke (mean age 66.5, SD 11.8, mean time since onset 16 months, range 7 - 56) and 24 controls (mean age 62.3, SD 11.61) performed balance and gait tasks in isolation and in conjunction with a cognitive task (remembering a seven item-shopping list). Three-dimensional movement analysis was used to assess anterior posterior (AP) and lateral (ML) sway; 5 m walk time, stride length and velocity.
RESULTS: In the single task condition, people with stroke had greater AP sway, reduced velocity and stride length and a longer 5 m walk time than controls (p < 0.01). In the dual task condition, sway reduced and gait slowed in both groups (p < 0.01 for AP sway, stride length, velocity, walk time); only the increase in walk time was greater in people with stroke than in the controls (F = 4.2, p = 0.046). Cognitive performance was maintained during the balance trials but deteriorated during the dual task gait trials in people with stroke (p = 0.017). Similar trends were noted for fallers and non-fallers with stroke: Only group effects for stride length and velocity reached significance (p < 0.05) and only the reduction in stride length was significantly greater among fallers than non-fallers (F = 12.3, p = 0.001).
CONCLUSIONS: People with stroke and controls employed similar strategies during the simultaneous performance of simple functional and silent cognitive tasks and maintained postural stability. Increased walk time and decreased cognitive recall were greater for people with stroke and reduced stride length distinguished fallers from non-fallers.