Analysis of the Relation Between Balance Control Subsystems: A Structural Equation Modeling Approach

Area of Science:

• Human physiology
• Biomechanics
• Neuroscience

Background:

• Maintaining balance is vital for daily activities and requires complex coordination of multiple balance control subsystems (BCSes).
• Previous research often studied BCSes in isolation, neglecting their interdependencies and combined impact on balance and fear of falling (FOF).

Purpose of the Study:

• To investigate the interrelationships between four key BCSes: Reactive Postural Control (RPC), Anticipatory Postural Adjustment (APA), Dynamic Gait (DG), and Sensory Orientation (SO).
• To examine the association between these BCSes, their interactions, and their relationship with fear of falling (FOF).
• To analyze the interplay of sensory inputs (vision, proprioception, vestibular) on balance using center of pressure (COP) parameters.

Main Methods:

• Utilized clinical scales to assess BCS functions and psychological factors like FOF.
• Employed hierarchical structural equation modeling (SEM) to analyze relationships between BCSes and FOF.
• Applied posturography to extract COP signal parameters.
• Used SEM with sparsity constraint to model sensory input interactions on balance.

Main Results:

• BCSes (RPC, APA, DG, SO) indirectly influence each other, mediated by overall balance ability.
• APA showed the strongest association with FOF, while RPC had the least.
• Vision, proprioception, and vestibular inputs directly interact, with proprioception being the most influential sensory subsystem.

Conclusions:

• This study provides the first numerical evidence that BCSes are interconnected and not independent.
• The findings highlight the complex interplay between motor control and sensory systems in maintaining balance.
• Understanding these interactions is crucial for diagnosing and managing balance disorders and improving clinical interventions.