Visual oscillation effects on dynamic balance control in people with multiple sclerosis.

Area of Science:

• Neuroscience
• Biomechanics
• Rehabilitation Science

Background:

• People with multiple sclerosis (PwMS) often exhibit balance deficits, particularly in dynamic environments.
• Their capacity to differentiate between self-motion and external object motion during ambulation remains under-explored.

Purpose of the Study:

• To investigate how medial-lateral visual field oscillations and object movements affect gait in PwMS and healthy controls.
• To assess the impact of virtual reality (VR) simulated environmental motion on dynamic balance.

Main Methods:

• Participants (14 PwMS, 11 controls) walked on a treadmill in a VR forest scene.
• Gait and dynamic balance were assessed under various visual conditions: static scene, scene oscillations, and object (tree) oscillations.
• Medial-lateral oscillations of the scene and virtual trees were manipulated in frequency and combination.

Main Results:

• Both PwMS and controls showed increased instability (step width, center of mass sway) with visual scene oscillations.
• High coherence indicated visuomotor entrainment to scene motion in both groups.
• PwMS, but not controls, demonstrated significantly greater instability when virtual objects (trees) moved.

Conclusions:

• Visual motion processing deficits in PwMS contribute to reduced dynamic stability.
• PwMS struggle to distinguish object motion from self-motion, impacting balance.
• Findings offer insights into stability control challenges for PwMS in real-world, dynamic environments.