Speech prosody impairments in Parkinson's disease : an acoustic analysis
Résumé
Background ; Prosodic features (pitch and intensity variation, pauses,rate) play a crucial role, besides the articulatory ones, on the intelligibility of ail languages around the world, namely in french.
Objective : To indentify and to quantify the speech prosody impairments in Parkinson's disease (PD)
Methods : 10 PD male patients (mean age : 57 y, mean disease duration : 9 y) were compared with 10 male controls (mean age : 59 y). AII subjects, after informed consent, were recorded during a loud voice reading task of a text (1 mn duration) with an acoustic system (EVA 2, SQ-lab, France). The PD patients were in OFF L. DOPA status (overnight washout > 12 hours). The distribution of tonal and intensity ranges (with mean fundamental frequency Fo in Hz and mean intensity in dB) were calculated, using the melodic tonal and intensity curves. The distribution and duration of silent pauses and the duration of vowels and consonants were also measured systematically from the acoustic signal. Statistical comparisons were made between PD patients and control sujects (paired Student's t test : significance at p < 0.05).
Results : A significant reduction in mean Fo and in mean intensity was observed in PD patients, with lack of the upper part of the tonal range, thus resulting also in the reduction of variability in pitch and intensity. The silent pauses duration and the mean vowel duration were significantly increased in PD patients, whereas the mean consonant duration was decreased in PD patients.
Conclusion : This acoustic approach can provide an objective and quantitative assessment of the speech dysprosody in Parkinson's disease, thus completing the classical perceptual assessment more focused on the articulatory disorders.
Acknowledgments : this study was supported by PHRC 2003 and France Parkinson.
Objective : To indentify and to quantify the speech prosody impairments in Parkinson's disease (PD)
Methods : 10 PD male patients (mean age : 57 y, mean disease duration : 9 y) were compared with 10 male controls (mean age : 59 y). AII subjects, after informed consent, were recorded during a loud voice reading task of a text (1 mn duration) with an acoustic system (EVA 2, SQ-lab, France). The PD patients were in OFF L. DOPA status (overnight washout > 12 hours). The distribution of tonal and intensity ranges (with mean fundamental frequency Fo in Hz and mean intensity in dB) were calculated, using the melodic tonal and intensity curves. The distribution and duration of silent pauses and the duration of vowels and consonants were also measured systematically from the acoustic signal. Statistical comparisons were made between PD patients and control sujects (paired Student's t test : significance at p < 0.05).
Results : A significant reduction in mean Fo and in mean intensity was observed in PD patients, with lack of the upper part of the tonal range, thus resulting also in the reduction of variability in pitch and intensity. The silent pauses duration and the mean vowel duration were significantly increased in PD patients, whereas the mean consonant duration was decreased in PD patients.
Conclusion : This acoustic approach can provide an objective and quantitative assessment of the speech dysprosody in Parkinson's disease, thus completing the classical perceptual assessment more focused on the articulatory disorders.
Acknowledgments : this study was supported by PHRC 2003 and France Parkinson.