Abstract
Progressive supranuclear palsy (PSP) is the most common Parkinson-Plus syndrome and is associated with early onset of dysphagia relative to Parkinson Disease. The current study contributes to the growing understanding of swallowing dysfunction in PSP by describing oropharyngeal swallowing characteristics in a large prospective cohort of participants with PSP employing a nationally standardized videofluoroscopy protocol and a disease severity scale developed expressly for PSP. Participants were 51 adults diagnosed with PSP. Each participant underwent a clinical interview and standardized videofluorographic assessment. Swallowing function was characterized with the Modified Barium Swallow Impairment Scale (MBSImP) and Penetration-Aspiration Scale (PAS). Variables of interest were participant-reported difficulties with liquids and/or solids; overall impression score for each of the 17 individual MBSImP components, as well as Oral Total Sum and Pharyngeal Total Sum; and PAS. Data were described with median interquartile range, counts, and proportions. Spearman's rank correlations were calculated between MBSImP scores and participant-reported indices, FOIS, and PSP Rating Scale. Approximately two-thirds of participants reported difficulties with liquids, solids, or both, although fewer than 15% reported modifying consistencies. Videofluorographic findings included predominant oral phase impairments, including back and forth rocking motion of the tongue, delayed initiation of the pharyngeal swallow, and oral residue. Pharyngeal phase impairments were relatively infrequent and comparatively mild, with the exception of reduced tongue base retraction contributing to pharyngeal residue, and mildly disrupted laryngeal vestibule closure. Disease severity correlated significantly with oral (r = .0.42, p = .0.002) and pharyngeal (r = 0.41, p = .0.003) total sum scores as well as with the oral phase components of oral transport (r = .0.33, p = .0.02) and initiation of the pharyngeal swallow (r = .0.38, p = .0.007), and PAS for thin liquids (r = .0.44, p = .0.001). The PSP Rating Scale was not more strongly correlated with swallowing impairment than has been reported for other disease severity rating scales. Dysphagia is a common complaint of patients with PSP. The current findings corroborate and expand upon those reported in the literature, detailing relatively more frequent and more severe oral phase impairments and relatively spared hyolaryngeal excursion. Further research is needed to characterize the progression of dysphagia in PSP and to determine whether dysphagia varies in character or in rate of progression across variants of PSP.