Reduction of Parkinson's-related dysphonia by thyroplasty.

Parkinson's-related dysphonia has a negative impact on the quality of speech by increasing the effects of the associated dysarthria. When this dysphonia is related to vocal fold adduction defect, constituting a real glottic insufficiency, vocal fold medialization can be proposed after failure of intensive voice and speech therapy. Acoustic and aerodynamic voice and speech analysis techniques, perceptual evaluation and estimation of vocal handicap, associated with fiberoptic laryngoscopy were performed to determine the indication for vocal fold medialization in these patients with glottic insufficiency. Vocal fold medialization by Montgomery thyroplasty implant was performed under local anesthesia and neuroanalgesia in two patients with Parkinson's disease presenting a dysphonia refractory to speech therapy. Postoperative evaluation showed improvement of voice quality with an increased number of harmonics and improvement of aerodynamic parameters. Vocal fold medialization by Montgomery thyroplasty implant effectively improved voice quality in these two patients allowing a more effective vocal fold adduction. The reducing of the hypophonia has a positive effect on the quality of oral communication. The medialization thyroplasty technique, under local anesthesia, allows intraoperative control of the voice as well as removal of the implant when necessary.

[Intrinsic and co-intrinsic vowel characteristics in cerebellar and parkinsonian dysarthrias]. / Caractéristiques vocaliques intrinsèques et co-intrinsèques dans les dysarthries cérébelleuse et parkinsonienne.

Few studies were made on the intrinsic and co-intrinsic vowel characteristics in neurologic dysarthrias. This work evaluates these parameters in a group of 4 subjects with cerebellar dysarthria suffering from a cerebellar degenerative syndrome and a group of 4 subjects with Parkinson disease suffering from parkinsonian dysarthria. These subjects were compared with 10 control subjects. An intensive speech treatment inspired from the Lee Silverman voice treatment (LSVT) was applied to one of the parkinsonian subjects of the study, with assessment before and after rehabilitation. The acoustic measures assessed the duration and the frequency of the vowels [a, i, ul indifferent contexts as well as their formant frequency and sentence duration. The results show different impairments according to the type of the dysarthria, and some forms of contrast transposition. Speech therapy restores subnormal contrasts.

Asymmetry of the laryngeal reflex responses to superior laryngeal nerve stimulation unrelated to the length of the recurrent nerves in the porcine model.

Electrical stimulation of the superior laryngeal nerve (SLN) can elicit reflex responses in the cricothyroid (CT) and thyroarytenoid (TA) muscles. We made bilateral recordings of the responses evoked in these muscles in piglets by the stimulation of either the right or the left superior laryngeal nerve (SLN). The stimulus intensity was gradually increased to study the "persistence" of the responses. We observed a direct, ipsilateral response in the CT muscle, and reflex, ipsilateral and crossed responses in both CT and TA muscles. The ipsilateral or contralateral responses obtained in TA muscles, following stimulation of the left SLN, were significantly delayed in comparison with those evoked by stimulation of the right SLN. This delay cannot be explained by the difference in length between the right and the left recurrent laryngeal nerves, but rather by an asymmetry in the sensory afferent pathway. The functional significance of this observation remains to be determined.

Dysprosody after severe closed head injury: an acoustic analysis.

OBJECTIVES: Neurological speech disorders (dysarthria and dysprosody) are known to be frequent sequelae after severe closed head injury. These disorders may dramatically alter communicative intent and accentuate social isolation. The aim was to provide an instrumental evaluation for prosodic production in a group of patients with severe closed head injury and to determine the correlations between prosodic production and neurobehavioural status. METHODS: Fifteen patients, at the subacute stage after severe closed head injury, were studied and compared with 11 controls, matched for age, sex, and duration of education. Each subject was required to read aloud a French sentence "Je m'en vais samedi matin" (I am leaving saturday morning) under six different prosodic intonations (neutral, affirmation, interrogation, happiness, sadness, anger). The recorded sentences were analysed using a sound signal analysis software (Signalyse) allowing the measurement of signal intensity and fundamental frequency. Statistical analyses were carried out using repeated measures analysis of variance (ANOVA). RESULTS: Patients with closed head injury were significantly less able than controls to modulate speech output (pitch and intensity) according to prosodic context. This deficit was particularly pronounced for the intonation feature of anger, question, and statement. No consistent correlations could be found between prosodic production and cognitive or behavioural data. CONCLUSIONS: Acoustic analysis of pitch and intensity may show impairments of prosodic production after severe closed head injury, which may be useful in rehabilitation planning. This impairment does not seem to reflect the eventual cognitive and behavioural deficits of the patients, but rather a specific disorder of modulation of speech output.

Electromyographic activity of strap and cricothyroid muscles in pitch change.

The EMG activity of the cricothyroid muscle (CT) and the three extrinsic laryngeal muscles (thyohyoid, TH; sternothyroid, ST, and sternohyoid, SH) were recorded throughout the voice range of one female and one male subject, both untrained singers. The voice range was examined using rising and falling glissandos (production of a sustained sound with progressive and continuous variation of fundamental frequency). Muscle activity was observed at various pitches during the glissandos. The strap muscle activity during the production of glissandos appears to be synergistic. At the lowest frequency, the CT is inactive but strap muscles (TH, ST, SH) are active. As frequency increases, strap muscle activity decreases while the CT controls frequency in the middle of the range. At higher frequencies the strap muscles once again become active. This activity might depend on the vocal vibratory mechanism involved. The role of the strap muscles at high pitches is a widely debated point but it seems that in some way they control the phenomena relevant to the rising pitch. The phasic-type strap muscle activity contrasts with the tonic-type activity of the CT. The CT closely controls the frequency, while the straps are not directly linked to the pitch but rather to the evolution of the frequency of voice production (speaking voice, singing voice, held notes, glissandos, trillo, vibrato, etc.).

[Change in laryngeal vibratory mechanism: a physiological entity]. / Le changement de mécanisme vibratoire laryngé: une entité physiologique.

The purpose of this paper is to examine the change of laryngeal vibratory mechanism in 10 males and 9 females trained and untrained singers. The electroglottographic (E.G.G.) data analysis demonstrated strong evidence to support the view that such event could be considered as a whole physiological entity. In fact findings clearly indicated biomechanical, neuromuscular and central levels in the control of the laryngeal vibration involved in the change of mechanism.