Parkinson's disease: speech and voice disorders and their treatment with the Lee Silverman Voice Treatment.

Speech and voice disorders are very common among individuals suffering from idiopathic Parkinson's disease. In this article we review evidence for laryngeal, respiratory, articulatory, and velopharyngeal disorders in this population. We present the essential concepts and outcome data for the Lee Silverman Voice Treatment, a behavioral treatment program that has yielded significant long-term improvement in speech and voice functions in individuals with idiopathic Parkinson's disease.