Proprioception deficits in chronic ankle instability associated with structural and functional alternations in cerebellar vermis

Ankle proprioception deficits have been widely reported in patients with chronic ankle instability (CAI), but their central neuropathological mechanisms have not been fully discussed. So, we aimed to figure out whether the structural and functional features of the cerebellar vermis differed between patients with CAI and healthy controls, and are associated with proprioception deficits in patients.

Twenty-two patients and 25 control individuals were enrolled in a cross-sectional investigation. All participants underwent structural and resting-state functional magnetic resonance imaging scanning to calculate voxel-based morphometry (VBM) and fractional amplitude of low-frequency fluctuation (fALFF) of the vermis. Between-group comparisons of the ankle instability-related subregions of the vermis were performed. Correlation analyses were performed between the outcomes of the surviving subregions and the proprioceptive scores of the ankle inversion discrimination apparatus for landing test.

The subregion of vermis Ⅳ/Ⅴ survived the multiple comparison correction to reveal a lower VBM value in patients than in healthy controls (Cohen's d ​= ​−0.968). The patients also showed significantly higher fALFF (Cohen's d ​= ​0.666) in this subregion. After controlling the demographic features, the proprioceptive scores were significantly correlated with VBM (r ​= ​0.622) and fALFF values (r ​= ​−0.512) in the group of patients.

Patients with CAI have lower gray matter volume and higher activity intensity in the cerebellar vermis than healthy control. The more severe proprioception deficits were significantly associated with the vermal volume and activity, which might be able to facilitate future diagnoses and treatments for CAI.