Patients with Parkinson's disease (PD) usually reveal speech disorders and, among other symptoms, the alteration of speech rhythm. The purpose of this study is twofold: (1) to test the validity of two acoustic parameters—%V, vowel percentage and VtoV, the mean interval between two consecutive vowel onset points—for the identification of rhythm variation in early-stage PD speech and (2) to analyze the effect of PD on speech rhythm in two different speaking tasks: reading passage and monolog. A group of 20 patients with early-stage PD was involved in this study and compared with 20 age- and sex-matched healthy controls (HCs). The results of the acoustic analysis confirmed that %V is a useful cue for early-stage PD speech characterization, having significantly higher values in the production of patients with PD than the values in HC speech. A simple speaking task, such as the reading task, was found to be more effective than spontaneous speech in the detection of rhythmic variations.

Experimental studies on different languages have shown that neurogenetic disorders connected with Parkinson's disease (PD) determine a series of variations in the speech rhythm. This study aims at verifying whether the speech of PD patients presents rhythmic abnormalities compared to healthy speakers also in Italian. The read speech of 15 healthy speakers and of 11 patients with mild PD was segmented in consonantal and vocalic portions. After extracting the durations of all segments, the vowel percentage (%V) and the interval between two consecutive vowel onset points (VtoV) were calculated. The results show that %V has significantly different values in mildly affected patients as compared to controls. For Italian, %V spans between 44% and 50% for healthy subjects and between 51% and 58% for PD subjects. A positive correlation was found between %V and the number of years of PD since its insurgence. The correlation with the age at which the disease insurges is weak. With regard to VtoV, PD subjects do not speak at a significantly slower rate than healthy controls, though a trend in this direction was found. The data suggest that %V could be used as a more reliable parameter for the early diagnosis of PD than speech rate. AbstractExperimental studies on different languages have shown that neurogenetic disorders connected with Parkinson's disease (PD) determine a series of variations in the speech rhythm. This study aims at verifying whether the speech of PD patients presents rhythmic abnormalities compared to healthy speakers also in Italian. The read speech of 15 healthy speakers and of 11 patients with mild PD was segmented in consonantal and vocalic portions. After extracting the durations of all segments, the vowel percentage (%V) and the interval between two consecutive vowel onset points (VtoV) were calculated. The results show that %V has significantly different values in mildly affected patients as compared to controls. For Italian, %V spans between 44% and 50% for healthy subjects and between 51% and 58% for PD subjects. A positive correlation was found between %V and the number of years of PD since its insurgence. The correlation with the age at which the disease insurges is weak. With regard to VtoV, PD subjects do not speak at a significantly slower rate than healthy controls, though a trend in this direction was found. The data suggest that %V could be used as a more reliable parameter for the early diagnosis of PD than speech rate.

Previous studies on Italian speech showed that the percentage of vocalic portion in the utterance (%V) and the duration of the interval between two consecutive vowel onset points (VtoV) were larger for parkinsonian (PD) than for healthy controls (HC). Especially, the values of %V were distinctly separated between PD and HC. The present study aimed to further test the finding on Mandarin and Polish. Twenty-five Mandarin speakers (13 PD and 12 HC matched on age) and thirty-one Polish speakers (18 PD and 13 HC matched on age) read aloud a passage of story. The recorded speeches were segmented into vocalic and consonantal intervals, and then %V and VtoV were calculated. For both languages, VtoV overlapped between HC and PD. For Polish, %V was distinctly higher in PD than in HC, while for Mandarin there was no significant difference. It suggests that %V could be used for automatic diagnosis of PD for Italian and Polish, but not for Mandarin. The effectiveness of the rhythmic metric appears to be language-dependent, varying with the rhythmic typology of the language.

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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.