Effect of visuospatial neglect on spatial navigation and heading after stroke

Area of Science:

• Neuroscience
• Rehabilitation Medicine
• Biomechanics

Background:

• Visuospatial neglect (VSN) significantly impacts locomotor heading control in post-stroke individuals.
• This impairment can compromise their ability to safely navigate and avoid moving obstacles during walking.

Purpose of the Study:

• To compare heading and head orientation changes in stroke individuals with (VSN+) and without (VSN-) VSN.
• To analyze obstacle avoidance and target reorientation when facing threats from different directions.

Main Methods:

• Participants with and without VSN walked in a virtual environment, encountering obstacles approaching from various directions (contralesional, head-on, ipsilesional).
• Key measures included obstacle avoidance (onset-of-heading change, mediolateral deviation) and target alignment (heading and head-rotation errors).

Main Results:

• VSN+ participants (75%) experienced more collisions with contralesional and head-on obstacles than VSN- participants (38%).
• VSN+ individuals exhibited an ipsilesional bias, using riskier strategies and showing greater heading change distances and target alignment errors.
• VSN- participants successfully used same-side deviation for diagonal obstacles, while VSN+ participants showed less optimal strategies.

Conclusions:

• The ipsilesional bias in VSN directly affects heading modulation during obstacle avoidance.
• This bias and the adoption of riskier strategies contribute to increased collisions and impaired goal-directed walking in stroke survivors with VSN.
• Future research should develop assessment and training tools for complex locomotor tasks like obstacle avoidance in VSN populations.