Increased Visual Use in Chronic Ankle Instability: A Meta-analysis

Purpose The underlying cause of balance impairments in chronic ankle instability (CAI) patients remains unknown, but an altered use of sensory information has been hypothesized as a potential cause. The purpose of this systematic review with meta-analysis was to determine whether CAI patients use somatosensory information to the same extent as uninjured controls during static single limb stance. Methods We searched PubMed, CINAHL, SPORTDiscus, and Scopus databases from origin to March 2016 using the combination of key words, including postural control, postural stability, single limb stance, single leg stance, single leg balance, single limb balance, and time to boundary (TTB). Eligible studies had to include instrumented single leg stance with both eyes open and eyes closed in healthy, CAI, or both groups as well as report TTB mean and SD values. Results A total of 11 articles were identified. Effect sizes using eyes closed to eyes open standardized mean differences and 95% confidence intervals were calculated for all studies that were included in this investigation. Similarly, pooled estimates for each TTB outcome were compared between the CAI and the uninjured control groups. The mean (95% confidence interval) of the mediolateral TTB (control: -1.50 [-1.71 to -1.29]; CAI: -2.04 [-2.31 to -1.77]), anterioposterior mean (control: -2.19 [-2.43 to -1.96]; CAI: -2.82 [-3.13 to -2.52]), and anterioposterior SD (control: -1.81 [-2.03 to -1.58]; CAI: -2.50 [-2.79 to -2.22]) did not overlap, indicating significant differences between two groups. Conclusion On the basis of our systematic review with meta-analysis, it appears that CAI patients do not use somatosensory information to the same extent as uninjured controls and instead upregulate the use of visual information during single limb stance.