BACKGROUND: Salivary dysfunction, including xerostomia and drooling, is common in Parkinson's disease and further impairs oral health and quality of life, which are already compromised in this population. Their effective management demands deeper insight into the complexity of salivary dysfunction.

OBJECTIVE: To examine the occurrence and associations of xerostomia and drooling complaints in individuals with Parkinson's disease.

METHODS: 111 individuals with Parkinson's disease (69.9 ± 7.7 years; 46.8% female) participated in an online survey. The questionnaire used validated scales (e.g., Xerostomia Inventory) and original questions. After descriptive analyses, multiple linear regression analyses identified factors (e.g., severity of motor impairment) associated with severity of xerostomia and drooling.

RESULTS: Xerostomia (64.9%) and drooling (27.0%) were common, with 18.0% of the individuals experiencing both concurrently. Xerostomia was associated with the presence of jaw symptoms (B = 4.63; 95% CI 1.86-7.40), chewing gum usage (B = 1.27; 95% CI 0.52-2.02), swallowing difficulties (B = 0.41; 95% CI 0.04-0.78) and taste alterations (B = 0.15; 95% CI 0.00-0.30). Drooling was associated with the severity of motor impairment (B = 0.40; 95% CI 0.18-0.60) and with swallowing difficulties (B = 0.64; 95% CI 0.14-1.15).

CONCLUSIONS: Xerostomia and drooling complaints frequently co-occur in individuals with Parkinson's disease. To prevent further deterioration of the oral health-related quality of life, a comprehensive evaluation of the underlying aetiology of salivary issues in people with Parkinson's disease is crucial to assist in determining suitable treatment.