Gray and White Matter Correlates of Dysphagia in Progressive Supranuclear Palsy

Background: Dysphagia is a common symptom of progressive supranuclear palsy often leading to aspiration pneumonia and death. Objective: The aim of this study was to examine how impairments of the oral and pharyngeal phases of the swallow and airway incursion during liquid swallows relate to gray and white matter integrity. Methods: Thirty-eight participants with progressive supranuclear palsy underwent videofluorographic swallowing assessment and structural and diffusion tensor head magnetic resonance imaging. Penalized linear regression models assessed relationships between swallowing metrics and regional gray matter volumes and white matter fractional anisotropy and mean diffusivity. Results: Oral phase impairments were associated with reduced superior parietal volumes and abnormal diffusivity in parietal and sensorimotor white matter, posterior limb of the internal capsule, and superior longitudinal fasciculus. Pharyngeal phase impairments were associated with disruption to medial frontal lobe, corticospinal tract, and cerebral peduncle. No regions were predictive of airway incursion. Conclusions: Differential patterns of neuroanatomical impairment corresponded to oral and pharyngeal phase swallowing impairments.