Effects of real-time visual feedback (D-WALL) on neuromuscular control in healthy adults: an fNIRS study

Neuromuscular control is essential for maintaining posture and performing motor tasks. Real-time visual feedback provides sensory information that may influence central neural processing and lower-limb muscle coordination during balance tasks. This study investigated the effects of visual feedback on neuromuscular control in healthy adults.

Thirty healthy adults aged 18-40 years completed four randomized balance conditions with or without real-time visual feedback. Physical activity and sports participation were assessed using the Tegner Activity Scale. Static and dynamic balance asymmetry were evaluated using the Prokin Balance System and Y-Balance Test, respectively. Prefrontal cortical activity was recorded using functional near-infrared spectroscopy (fNIRS), and lower-limb muscle activation was assessed using surface electromyography (sEMG).

Among participants with lower physical activity levels (Tegner score < 5), left prefrontal cortex (lPFC) activation was significantly higher with visual feedback than without feedback. Among participants with greater bilateral balance asymmetry, right prefrontal cortex (rPFC) activation was significantly higher during cross-body X-shaped arm movements performed with visual feedback. Exploratory sEMG data from seven eligible participants further showed a higher relative activation ratio of the left posterior to anterior thigh muscles during visual-feedback tasks in participants with lower physical activity and poorer balance symmetry.

Visual feedback was associated with altered prefrontal activation and reorganization of lower-limb muscle coordination during motor tasks in healthy adults.