[Parkinsonian dysarthria]

Perceptual, acoustic and physiological (electromyographic and kinematic) studies addressing the features of the Parkinsonian speech are reviewed. Perceptual features are the following: 1) aprosody, i.e. monopitch, monoloudness, diminished stress contrasts and rate abnormalities, 2) impairment of articulation such as imprecise consonants, and 3) vocal quality deviation as harsh or breathy voice. The physical basis that is acoustic parameters corresponding to these perceptual impressions, such as fundamental frequency, intensity, duration, speech rate, have been analyzed. However, movement studies associated with electromyographic analysis in an important adjunct to more traditional investigations. The physiological studies are yet limited, they show that patients with Parkinson's disease have 1) reduced articulatory displacements relative to normal speakers, which may appear as rigidity, 2) improper coordination of agonist-antagonist muscle pairs or groups. Besides, some results show that pharmacological or surgical treatment improving akinesia, rigidity and tremor are not always successful in speech.