[Acoustic study of sustained vowels made by patients with recurrent nerve paralysis after thyroidectomy]. / Etude acoustique de voyelles soutenues produites par des patients présentant une paralysie récurrentielle après thyroïdectomie.

The objective of this work is to evaluate the consequences of thyroid surgery on the voice of patients suffering from recurrent paralysis. The consequences of the surgery are evaluated using a corpus of sustained vowels in order to identify the various disruptions that this procedure may produce. This research also looks for possible compensatory and/or readjustment strategies that can be used by a patient alone and with the help of speech therapy. Acoustic measurements considered are fundamental frequency (F0), Harmonics-to-Noise Ratio (HNR), and vowel space area. This is a longitudinal study, as all patients are recorded once a month during three months after surgery. Results reveal a modification of all parameters in the early recording stages. However, time and speech therapy contribute to obtaining expected values of the measured parameters, and thus to improvement of vocal quality.

[Formant structures of vowels produced in stutterers' speech in normal and fast speech rates]. / Etude de la structure formantique des voyelles dans la parole bègue en vitesses d'elocution normale et rapide.

OBJECTIVE: The aim of this study is to analyse the steady-state portion of the first two formants (F1 and F2) in the production of [CVp] sequences, containing vowels [i, a, u] pronounced in two speech rates (normal and fast), by groups of untreated and treated stutterers, and control subjects. MATERIAL AND METHOD: We recorded 15 speakers (5 control speakers, 5 non-treated stutterers and 5 treated stutterers) who had to repeat sentences containing [CV] sequences ten times, in normal and fast speech rates, where [C] was [p], [t] or [k] and [V], [i], [a] or [u]. RESULTS: Comparing data between the three groups of speakers, a vowel space reduction is observed for stutterers at a normal speaking rate, compared with control speakers and treated stutterers. When speech rate increases, no reduction of vowel space is noticeable for non-treated stutterers, contrary to treated stutterers and controls. CONCLUSION: Results for stutterers could be interpreted in terms of lack of articulatory flexibility.

Vocal tract area function estimation from midsagittal dimensions with CT scans and a vocal tract cast: modeling the transition with two sets of coefficients.

The generation of area functions from measurements of the sagittal section is an important step in the study of the relation between vocal tract geometry and speech acoustics. We present a new model to perform this transformation, inspired by the alpha beta model of Heinz & Stevens (1965). Our model is based on analysis of a vocal tract cast for large sagittal dimensions and for small sagittal dimensions on CT scans of the vocal tract constriction zones for the three cardinal vowels [i, a, u] of French. We extracted two sets of coefficients, appropriate for large and small sagittal dimensions respectively. We then compared the predictions of the model with those of other models from the literature. Finally, the usefulness of this dual coefficient procedure for the acoustic simulation of vowels was tested using sagittal sections generated by an acoustic model of the vocal tract.