Subtle esophageal motility alterations in Parkinsonian Syndromes: synucleinopathies vs. tauopathies.

Background: Esophageal dysfunction is a frequent phenomenon in Parkinson's disease during all disease stages, but data about esophageal involvement in atypical parkinsonian syndromes as well as possible differences between alpha-synucleinopathies and tauopathies, including causative links to the origin of the dysfunction, are lacking so far. Objective: To describe esophageal alternation patterns in different parkinsonian syndromes and to look for differences supporting the hypothesis of alpha-synuclein aggregation being linked to gastrointestinal impairment in parkinsonian syndromes. Methods: We performed an analysis and comparison of esophageal high-resolution manometry examination parameters in n = 10 patients with Parkinson's disease, n = 10 patients with multiple system atrophy (both alpha-synucleinopathies), n = 10 patients with progressive supranuclear palsy (tauopathy), and n = 10 age-matched controls. Additionally, pharyngeal dysphagia was evaluated by an endoscopic examination of swallowing in all three patient groups. Results: Statistically significant lower values for esophageal peristalsis and distal contractile integral were found for both groups of alpha-synucleinopathies (Parkinson's disease and multiple system atrophy) in comparison to the patients with tauopathy (progressive supranuclear palsy group), as well as the age-matched controls, where pathological pharyngeal findings were similar in all patient groups. Conclusions: Subtle esophageal motility alterations in parkinsonian syndromes seem to be limited to alpha-synucleinopathies, but are not measurable in tauopathies, indicating a causative connection between pathological alpha-synuclein aggregation in gastrointestinal tissues and esophageal involvement.