Drooling in Parkinson’s Disease: A Multifactorial Symptom

Background: Drooling or Sialorrhoea is considered as a common non-motor symptom in patients with Parkinson’s disease (PD), however the mechanism of drooling in PD is unknown. Objectives: The aim of this study was to evaluate the impacts of dysphagia and cognitive function on drooling in PD. Methods: Eighty-five patients with PD participated in this cross-sectional study. After diagnosis of PD, its severity was determined by the Hoehn and Yahr (HY) scale, which is consisted of five stages and explains the progression symptoms of PD. Evaluation of drooling was done by the Drooling Severity and Frequency scale (DSFS). Dysphagia was diagnosed using the Persian version of Northwestern dysphagia patient check sheet (NDPCS) and cognitive function was assessed through the Persian version of Mini-Mental State examination (MMSE). Data analysis was done with SPSS 22. All analyses were two-tailed tests and a P value of less than 0.05 was considered as statistically significant. Results: The mean total DSFS score was 3.96 ± 1.65, and using a cut-off point of two, the prevalence of drooling was 70.6% (n = 60) in PD patients. In adjusted analysis, the low MMSE score, high HY score, and dysphagia were all associated with drooling. Conclusions: Although concurrence of dysphagia and drooling is possible in PD, we should also consider cognitive impairments as an important factor in the occurrence of drooling. In addition, further studies are needed to investigate the impact of cognitive domains on drooling in Parkinson’s patients.