Structural and Functional Changes in the Cerebellum and Brainstem in Patients with Benign Paroxysmal Positional Vertigo.

Benign paroxysmal positional vertigo (BPPV) is one of the most common peripheral vestibular diseases. Since the peripheral vestibular system connects with the cerebellum via the brainstem, repeated episodic vertigo may result in progressive structural and functional changes in the cerebellum and brainstem. In the present work, voxel-based morphometry (VBM) of T1-weighted images and resting-state functional magnetic resonance imaging (fMRI) in 32 patients with BPPV and 32 matched healthy controls were used to assess cerebellar and brainstem anatomical and spontaneous resting-state brain activity alterations associated with BPPV. We used a spatially unbiased infratentorial template toolbox in combination with VBM to analyze cerebellar and brainstem gray matter volume (GMV), fractional amplitude of low-frequency fluctuations (fALFF), and regional homogeneity (ReHo). Patients with BPPV showed decreased GMV in the right cerebellum posterior lobe/cerebellar tonsil extending to the cerebellum anterior lobe and pons relative to healthy controls. BPPV patients also exhibited significantly higher fALFF values in the right pons and left pons and higher ReHo values in the left cerebellum posterior lobe/Crus2 than the controls. Furthermore, the fALFF z-scores in the pons were positively correlated with the duration of vertigo at baseline and dizziness visual analog scale scores 1 week after canalith repositioning procedures (CRPs). BPPV patients exhibited structural and functional changes in the cerebellum and pons, which may reflect the adaptation and plasticity of these anatomical structures after repeated attacks of episodic vertigo. These results indicate that the changes in pons function may be closely related to residual dizziness after CRPs.