Alteration in the dynamics of ipsilateral cerebellar fluctuations and its association with balance performance in recreational athletes with chronic ankle instability: A cross-sectional study of resting-state fMRI.

OBJECTIVES: Chronic ankle instability (CAI) is not only associated with those peripheral neuromuscular impairments but also with the functional changes in the supraspinal regions. Nevertheless, the characteristics of the cortical elements in CAI remain poorly understood. This study aimed to examine the dynamics of resting-state BOLD and ankle-related functional performance in recreational athletes with CAI, as well as explore the associations between neural fluctuations and ankle functional performance.

METHODS: This cross-sectional design study recruited 82 participants, comprising 41 active recreational athletes with CAI (CAI group) and 41 active recreational athletes without CAI (Control group). Data on joint position sense, one-leg standing balance, and resting-state fMRI were collected from both groups. A two-sample t-test was used to determine the difference in amplitude of low-frequency fluctuation (ALFF), fractional ALFF (fALFF), and regional homogeneity (ReHo) between the two groups. Linear regression analysis evaluated the associations between functional performance and dynamics of resting-state BOLD in the two groups.

RESULTS: Compared with control group, athletes with CAI had lower ALFF values in the bilateral supplementary motor area and reduced ReHo values in the right precentral gyrus and postcentral gyrus, while higher ALFF and ReHo values in the right cerebellum. Moreover, athletes with CAI had lower fALFF values in the left superior frontal gyrus and the right superior frontal gyrus than controls. The sway velocities of center of pressure in the one-leg standing with eyes closed condition were negatively associated with ALFF and ReHo values in the right cerebellum cluster.

CONCLUSIONS: Athletes with severely right-sided CAI had different neural fluctuations compared with controls. Elevated ALFF and ReHo values in the right cerebellum cluster were associated with balance control, suggesting that high ipsilateral cerebellar activity and homogeneity may compensate for balance control in athletes with CAI.