Article révisé par les pairs
| Résumé : | In order to study methods of detecting a lack of vocal efficiency due to pathological changes of the larynx and of quantifying this lack at the acoustic level, we defined an acoustic parameter related to the efficiency of phonation and tested its performance in terms of its ability to discriminate between normal and dysphonic speakers. We extracted a so-called vocal efficiency feature (VEF) from the autocorrelation function of the steady portion of the isolated French vowel /a/. During the first stage we established by simulation the relationship between the VEF and the shape and duty cycle of the glottal waveform. The simulation showed that the lower the VEF values were, the smaller was the glottal closure quotient and the more symmetric the waveform. In the second stage we collected a set of dysphonic and a set of normal speech samples and computed the VEF for each. The proposed VE measure permitted discrimination between normal and dysphonic speakers. The relevance of the resulting classification was illustrated by its interpretation in the framework of a theoretical model [20]. The proposed parameter is most useful. It permits the detection at the acoustic level of types of pathologies which do not lead to increased perturbation or noise in the speech signal. © 1985. |
