15th International Congress of Phonetic Sciences (ICPhS-15)
We carried out a study based on a dynamical model of speech-rhythm production in patients with Parkinson's disease (PD). This model predicts that rhythm is implemented by a coupled-oscillator system. The synchronization of these two oscillators is given by neuromotor control. Three subjects with PD were instructed to read given sentences. For acoustic analysis, segments were grouped into two kinds of rhythmic programming units: syllable and IPGC, and calculations of z-scores from the mean duration of these units were made. One curve relative to syllables - microrythmic level - and another relative to IPGCs - macrorythmic level - pointed at no synchrony between the two levels. We believe that the lack of synchrony between the two levels is due to the absence of synchronization in the coupling of the two oscillators. Since the coupling is determined by neuromotor control, the rhythmic-alterations finding is not a result only from motor alterations; there is also a cognitive aspect.
Bibliographic reference. Soares, Maria Francisca de Paula / Silva, Adelaide Hercilia P. (2003): "Parkinson's speech rhythm: a phonetic-phonological analyses", In ICPhS-15, 2497-2500.