Levodopa-induced modifications of prosody and comprehensibility in advanced Parkinson's disease as perceived by professional listeners.

The prosodic aspects of hypokinetic dysarthria in Parkinson's disease (PD) have been the focus of numerous reports. Few data on the effects of levodopa on prosody, more specifically on the effects on the variability of prosodic characteristics such as pitch, loudness and speech rate, are available in advanced PD. The relation between these characteristics and comprehensibility is currently unknown. These topics are the focus of the present report. Ten patients with advanced PD were evaluated, with and without medication, by four speech-language pathologists during a reading task. A significant improvement of variability in pitch and loudness was demonstrated after medication intake. Comprehensibility improved following medication administration. Results are compared with previous studies.