Multiscale dynamics of single-leg standing postural control in chronic ankle instability

Area of Science:

• Biomechanics
• Neurology
• Sports Medicine

Background:

• Chronic ankle instability (CAI) is a prevalent condition affecting postural control.
• Understanding the complexity of postural sway is crucial for assessing functional deficits in CAI.

Purpose of the Study:

• To investigate postural sway complexity in individuals with CAI during static postural control.
• To examine the relationship between the duration of ankle instability and postural sway complexity.
• To determine if multiscale entropy can serve as an indicator for impaired postural control in CAI.

Main Methods:

• Sixty-one participants (35 CAI, 26 healthy controls) were recruited.
• Static postural balance was assessed using a 20-second single-leg stance (right leg) under eyes open (EO) and eyes closed (EC) conditions.
• Multiscale entropy analysis quantified the complexity of center of pressure (CoP) fluctuations in anterior-posterior (AP) and medial-lateral (ML) directions.

Main Results:

• CAI participants showed significantly lower AP and ML sway complexity in the EO condition compared to healthy controls (p<0.05).
• No significant differences in sway complexity were observed between groups in the EC condition.
• A significant negative correlation was found between the duration of ankle instability and ML sway complexity in the EC condition among CAI participants (r=-0.484, p=0.023).

Conclusions:

• CAI is associated with reduced postural sway complexity, particularly with eyes open, suggesting impaired adaptability to sensory perturbations.
• Multiscale entropy analysis is a promising tool for identifying deficits in postural control in individuals with CAI, especially under visual input.
• The duration of CAI may influence the complexity of postural control in specific sensory conditions.