A diachronic study on Italian speech rhythm in Parkinson’s Disease

Parkinson’s Disease dysarthria affects the speech motor
control, causing alterations at the suprasegmental level of
speech. In previous researches, vowel percentage (%V) and
the mean interval between two consecutive vowel onset points
(VtoV) were effectively used in the synchronic description of
the rhythmic variations of Italian PD speech, compared to
healthy speech, even at a very early stage of the disease.
This study aims at verifying the early alteration of PD
speech rhythm using a diachronic approach. To reach this
goal, a corpus of read speech produced by a single PD subject
(female, 66 years old) has been collected, consisting of 15
radiophonic speech samples (about 100 s each) on the same
topic, recorded between 2001 and 2021.
The speech samples were manually segmented in
consonantal and vocalic intervals by means of Praat, allowing
the calculation of %V and VtoV.
The results show an alteration of %V values since 2018,
two years before the diagnosis and the insurgence of motor
symptoms.
Moreover, first results of the application of the automatic
segmentation performed by SPPAS on a selection of PD
speech samples will also be presented.