Sialorrhoea and drooling in patients with Parkinson's disease: epidemiology and management.

Although often less recognized than motor symptoms, non-motor effects represent an important source of disability for many parkinsonian patients. Of these non-motor symptoms, sialorrhoea, defined as the inability to control oral secretions resulting in excessive saliva accumulation in the oropharynx, constitutes perhaps one of the most bothersome and troubling problems, often causing social embarrassment and isolation. In patients with Parkinson's disease (PD), this symptom is thought to be due to restricted swallowing and dysfunction, rather than to hypersecretion of saliva. Only a few well designed studies have been conducted to determine the optimal treatment for sialorrhoea in PD. A combination of approaches appears to be necessary to obtain successful results.