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Chronic ankle instability (CAI) is associated with sensory-perceptual and neurocognitive impairments that can negatively affect balance control, especially under cognitively and visually demanding conditions. Previous study reported the difficulty of dual task should be considered to screen individuals with CAI from uninjured group. Although individuals with CAI have increased visual reliance, the effects of dual task under visual interference remain not clear.
This study aimed to investigate the effects of dual tasking with visual interference on balance performance in individuals with and without CAI. Additionally, it explored the relationship between visual reliance and dual task cost (DTC), hypothesizing that visual reliance would be positively associated with DTC.
A total of 40 participants (n=20 CAI, n=20 control) completed static single-leg balance tests under single- and dual task conditions across three visual input levels: eyes open, eyes closed, and stroboscopic vision at a 5Hz. Dual task conditions included a Stroop task and serial subtraction. Center of pressure (COP) data was sampled at 200 Hz using a force plate and analyzed for spatial, temporal and frequency domain metrics. 2-way repeated measure ANOVA for each dual task and Pearson correlation coefficients were used to assess their relationships.
Contrary to the initial hypothesis, dual tasking with visual interference did not induce significantly greater balance impairment in individuals with CAI compared to controls. Instead, changes in sensory information alone (e.g., eyes closed, SV) led to higher DTC across both groups. A broad range of individual responses to dual-tasking was observed, irrespective of injury history. Frequency analysis revealed significant vision effects in mid-frequency ratios during Stroop dual-task conditions, suggesting that postural strategies were adaptively modified based on visual-cognitive demands. Notably, individuals exhibited heterogeneous shifts toward low- or high-frequency control strategies. A significant correlation was found between greater visual reliance and higher DTC values, indicating impaired sensory reweighting ability.
Combining visual and cognitive challenges can reveal complex, task-specific adaptations in postural control that traditional dual-task paradigms may overlook. While sensory interference exerted a stronger effect on balance than cognitive load alone, substantial individual variability was noted. These findings highlight the need for more sensitive, multidimensional assessments of sensory and cognitive integration in CAI. Future studies refining frequency-based analyses and examining heterogeneous dual-task responses are warranted to advance CAI screening and rehabilitation strategies.