Effects of visual disruption on static and dynamic postural control in people with and without chronic ankle instability

Introduction: Chronic Ankle Instability (CAI) is a chronic syndrome resulting from repeated ankle sprains that lead to persistent dysfunction. the purpose of this study is to determine whether visual disruption could influence static and dynamic postural control in people with and without chronic ankle instability (CAI), with the objective of gaining a comprehensive understanding of the interactions between visual inputs and postural control. Methods: Thirty people with CAI (21 males and 9 females, age = 22.0 +/- 1.8 years, height = 174.4 +/- 10.2 cm, body mass = 72.5 +/- 15.4 kg; Cumberland Ankle Instability Tool (CAIT) score = 19.7 +/- 1.8) and twenty-nine without CAI (24 males and 5 females, age = 22.9 +/- 1.6 years, height = 172.8 +/- 8.0 cm, body mass = 69.0 +/- 11.3 kg; CAIT score = 29.0 +/- 0.7) were recruited. Their static and dynamic postural control was measured in two conditions with or without visual disruption, simulated using stroboscopic glasses. Static postural control was measured during single-limb standing and represented by root mean square (RMS) of the plantar center of pressure (CoP), dynamic postural control was measured during a Y-balance test and represented by the relative reach distance. Two-way mixed ANOVA (between group: CAI vs non-CAI, within group: normal vision vs visual disruption) was used to analyze data. Results and discussion: Significant interactions were detected in the CoP-RMS in the anteroposterior (AP) (p = 0.021, eta(2)(p) = 0.090) and mediolateral (ML) (p < 0.001, eta(2)(p) = 0.208) directions, and the relative reach distances in the posteromedial (PM) p = 0.023, eta(2)(p) = 0.088) and posterolateral (PL) (p = 0.009, eta(2)(p) = 0.113) directions, from normal vision to visual disruption. The CoP-RMS in the AP and ML directions significantly increased and the relative reach distances in the PM and PL directions significantly decreased in people with CAI while remaining unchanged in those without CAI. People with CAI are susceptible to visual disruption on postural control, highlighting the importance of visual input in maintaining stable posture in this population.