Dry mouth: an overlooked autonomic symptom of Parkinson's disease.

There is involvement of salivary glands by α-synuclein pathology in PD. However, the prevalence of dry mouth has not been systematically assessed in these patients. We studied 97 PD patients and 86 controls using a structured questionnaire. Dry mouth was reported by 60.8% of PD patients and 27.9% of controls (p < 0.0001). Dry mouth and drooling coexisted in 30% of cases. Only 12% of patients had reported dry mouth to their physicians. Dry mouth is a frequent but underreported symptom and may be an early manifestation of autonomic involvement in PD.