Excessive daytime sleepiness is associated to the development of swallowing impairment in a cohort of early stage drug naïve Parkinson's disease patients

Abstract

Objective: The aim of the present study was to investigate the potential predictors of subjectively reported swallowing impairment in a cohort of early-stage and drug naïve Parkinson's disease patients.

Methods: A retrospective analysis of the Parkinson Progression Markers Initiative (PPMI) data was conducted. PD patients with score ≥ 1 on MDS-UPDRS "item 2.3" and on SCOPA-AUT "question 1" were classified as "dysphagic" and were compared with "non-dysphagic" patients at baseline. After excluding baseline dysphagic subjects, we assessed the predictors of the development of dysphagia in the third year of follow-up.

Results: The baseline prevalence of dysphagia in PD was 10.4%, growing as high as 19.1% within year 3. Compared to PD subjects not complaining swallowing difficulties, dysphagic patients had significantly higher scores on REM sleep behavior questionnaire, Epworth sleepiness scale (ESS), geriatric depression scale and MDS-UPDRS I (p < .01), significantly lower caudate [¹²³I]FP-CIT uptake parameters and BMI, and mild cognitive changes at symbol digit modalities (p < .01). In the longitudinal analysis of non-dysphagic patients, 14.6% developed dysphagic symptoms at year 3. Excessive daytime sleepiness estimated through ESS was strongly related to the development of swallowing impairment at year 3 in the univariate (odds ratio 3.2, p < .001) and multivariate regression model (odds ratio 2.5, p = .01).

Conclusions: Early-stage PD patients often report swallowing difficulties. We found a close relationship between excessive daytime sleepiness and the development of swallowing impairment over three years of follow-up of de novo patients.

Keywords: Circadian rhythm; Dysphagia; Excessive daytime sleepiness; Non-motor symptoms; Parkinson progression marker initiative (PPMI); REM sleep behavior disorder.