Dual tasking negatively impacts obstacle avoidance abilities in post-stroke individuals with visuospatial neglect: Task complexity matters!

Abstract

Background:

Persons with perceptual-attentional deficits due to visuospatial neglect (VSN) after a stroke are at a risk of collisions while walking in the presence of moving obstacles. The attentional burden of performing a dual-task may further compromise their obstacle avoidance performance, putting them at a greater risk of collisions.

Objective:

The objective of this study was to compare the ability of persons with (VSN+) and without VSN (VSN–) to dual task while negotiating moving obstacles.

Methods:

Twenty-six stroke survivors (13 VSN+, 13 VSN–) were assessed on their ability to (a) negotiate moving obstacles while walking (locomotor single task); (b) perform a pitch-discrimination task (cognitive single task) and (c) simultaneously perform the walking and cognitive tasks (dual task). We compared the groups on locomotor (collision rates, minimum distance from obstacle and onset of strategies) and cognitive (error rates) outcomes.

Results:

For both single and dual task walking, VSN+ individuals showed higher collision rates compared to VSN– individuals. Dual tasking caused deterioration of locomotor (more collisions, delayed onset and smaller minimum distances) and cognitive performances (higher error rate) in VSN+ individuals. Contrastingly, VSN– individuals maintained collision rates, increased minimum distance, but showed more cognitive errors, prioritizing their locomotor performance.

Conclusion:

Individuals with VSN demonstrate cognitive-locomotor interference under dual task conditions, which could severely compromise safety when ambulating in community environments and may explain the poor recovery of independent community ambulation in these individuals.