Prosodic expression and levodopa in Parkinson's disease

Abstract

rosody is an important supra-segmental aspect of speech. Through prosodic varia-tion, many cues regarding message intention, affected expression and type of in-terpersonal relationship are given to the listener. The main characteristics involved in prosody are fundamental frequency and loudness variability, speech rate, dura-tion of pauses, vowel length, force of articulation and rhythm. Prosody pattern is an individual characteristic that requires an intact central and periphe-ral nervous system. It is highly influenced by biological factors, cultural features, personality traits, emotional states and aging. It is easy to understand that many neurological and men-tal disorders can produce a direct impact on prosodic expression. For example, maniacal epi-sodes are vocally characterized by uncontrolled intensity and excessive frequency variability; on the other hand, vocal fold paralysis can severely limit frequency and loudness control, im-pairing the speaking and singing voice. Parkinson’s disease (PD) patients suffer from reduction of the extent of all movements re-lating to speech, involving three subsystems: respiratory, phonatory and articulatory. In addi-tion, swallowing may also be impaired