Subtle oromotor signs in early Parkinson’s disease before clinical manifestations of dysphagia

Abstract

Background: Swallowing is complex phenomena comprising oral (preparatory and pre-swallow positioning), oropharyngeal, pharyngeal and esophageal phases. The timing of these phases is controlled by brain stem pattern generators including reflex for oropharyngeal propulsion and transit. Dysphagia in Parkinson's disease (PD) commonly observed at late stages with aspiration, pneumonia and hospitalization. Objective: Can subtle oromotor signs (if any) be observed for planning early interventions in PD Methods: The present study investigated oromotor function in fourteen early PD (onset ≤2years; H&Y ≤2.5) with dynamic MRI using saline (water) bolus and compared with seven age-matched healthy controls. Results: All the patients with PD were non-symptomatic for dysphagia by self-reporting, and on clinical assessment (Part-II MDS-UPDRS, Swallowing disturbance questionnaire, SDQ and Clinical assessment of dysphagia in neurodegeneration, CADN). Qualitatively MR images visualized, differences in PD compared to healthy controls for tongue-wave, velar-closure or release, bolus placement, oropharyngeal reflex-initiation, transit-time, epiglottic-closure-coordination and post-swallow oral or pharyngeal residue. Descriptive analysis showed higher variability of velar-closure, oropharyngeal- and pharygoesophageal-transit time in patient with PD. Group analysis (two-sample) show significant difference for velar-closure. Conclusion: Multiple lingual-waves, reverse-tongue thrust, with delayed velar control attributed to incoordinated muscular rhythm. Variable oropharyngeal transit time (0.64 to 2.25 msec) in PD ascribed to brainstem degenerative changes. Findings imply that subtle observable early oromotor signs as pre-clinical manifestation when evaluated with non-invasive, non-contrast dynamic MRI support early intervention, to prevent late-stage aspiration episodes and consequent hospitalizations.