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At least 19 recordsLinked to original sources

PubMed1991

The role of the posterior cricoarytenoid muscle in phonation: an electromyographic investigation in dogs.

The activity of the posterior cricoarytenoid muscle during respiration has been well investigated electromyographically. Its activity during phonation, however, has not been studied systematically. We, therefore, focused our attention on the phonatory activity of the posterior cricoarytenoid muscle to confirm whether it also contracts during phonation, as has been reported by some researchers. In our series of 12 adult dogs, the posterior cricoarytenoid was active in 11 dogs and inactive in one dog during phonation. Our present study also showed that the posterior cricoarytenoid activity was stronger for phonation than for inspiration in 6, stronger for inspiration than for phonation in 3, and the same for phonation and inspiration in 2 dogs. The results obtained from the present electromyographic evaluation demonstrated that the posterior cricoarytenoid is activated during phonation. The authors believe that the posterior cricoarytenoid muscle has phonatory function and that the phonatory effect of this muscle on the vocal cord may play an important role in precise glottis control.

Animals↗

PubMed1992

Effects of posture, phonation and observer on Mallampati classification.

We have studied the effects of phonation and posture on the Mallampati classification of view of the pharyngeal structures. Differences between observers were allowed for by the experimental design and log-linear modelling. Sixty-four patients were assessed on the ward, sitting upright, with and without phonation, by each of two observers. Another 64 patients were assessed without phonation, but both upright and supine, again by both observers. Phonation (the patient saying "Ah") produced a marked, systematic improvement of view; moving to the supine posture produced a small, systematic, non-significant worsening of the view. Differences between observers were non-systematic but substantial. About 25% of patients phonated spontaneously. It is recommended that anaesthetists make their own assessments of Mallampati classification, with the patient in either of the postures but always either with or without phonation, and thereby gradually "calibrate" their assessments against the degree of difficulty encountered in intubation.

Humans↗

PubMed1978

Cerebellar regulation of phonation in rhesus monkey (Macaca mulatta).

Five rhesus monkeys (Macaca mulatta) were trained to emit a "coo" vocalization with a duration of at least 500 msec. After stable performance was achieved cerebellar lesions were introduced, and various pre- and postlesion measures of phonation and of laryngeal EMG activity were compared to assess the effects of the lesions. The phonatory changes were interpreted with respect to possible laryngeal or respiratory modifications. The relation between fundamental frequency and intensity of phonation was changed in some animals, with no obvious alterations in either fundamental frequency or intensity considered separately. Intensity of phonation was decreased while duration was prolonged in two animals. Fundamental frequency of phonation was also affected in some animals. Reliable laryngeal EMG was obtained in two animals and was affected by cerebellar lesions. These results indicate that normal cerebellar function is involved in the control of fundamental frequency, intensity, duration, and the coordination of the laryngeal and respiratory systems for the control of phonation.

Acoustics↗

PubMed1992

Modifying electroglottograph-identified intervals of phonation: the effect on stuttering.

Single-subject experiments were conducted with an adolescent and an adult male who stutter to assess the effect on stuttering of changing the frequency of phonation intervals that were within prescribed duration ranges during spontaneous speech. Electroglottograph-identified intervals of phonation were measured using a computer-assisted biofeedback system. Both subjects demonstrated that their stuttering could be controlled by modifying the frequency of phonation intervals within short duration ranges. The experimental effects not only replicated earlier findings but were demonstrated to be independent of changes in speaking rate, or alterations to other intervals of phonation, and produced little disruption to speech naturalness. The theoretic implications of these findings are discussed.

Adult↗

PubMedDate not supplied

Firing pattern of motor units in the vocal muscle during phonation.

Electromyographic activity of the vocal muscle was analysed in 10 subjects during the phonation of different vowels and with different voice pitches. Analysis of the firing pattern of single or a few motor units was performed with the aid of an amplitude discriminator on the computer. The firing rate increases with increasing voice pitch (in the region co-ho the decrease of mean interspike interval with the slope 30-40 msec/octave was found). In the firing pattern of several motor units the periodicity was observed to be correlated with the voice pitch. The period of 8 msec corresponding H, 123 Hz, decreased to about 6 msec during phonation of do, 147 Hz. The periodicity was present both in units with pure prephonatory activity and in units which were active during phonation. It seems possible that the activity in the vocal muscle changes characteristically during the phonation of different vowels.

Adult↗

PubMed1992

Phonation threshold pressure: a missing link in glottal aerodynamics.

Phonation threshold pressure has previously been defined as the minimum lung pressure required to initiate phonation. By modeling the dependence of this pressure on fundamental frequency, it is shown that relatively simple aerodynamic relations for time-varying flow in the glottis are obtained. Lung pressure and peak glottal flow are nearly linearly related, but not proportional. For this reason, traditional power law relations between vocal power and lung pressure may not hold. Glottal impendance for time-varying flow should be defined differentially rather than as a simple ratio between lung pressure and peak flow. It is shown that the peak flow, the peak flow derivative, the open quotient, and the speed quotient of inverse-filtered glottal flow waveforms all depend explicitly on phonation threshold pressure. Data from singers are compared with those from nonsingers. The primary difference is that singers obtain two to three times greater peak flow for a given lung pressure, suggesting that they adjust their glottal or vocal tract impedance for optimal flow transfer between the source and the resonantor.

Female↗

PubMedDate not supplied

Stability of mandibular position in continuous vowel phonation.

The stability of the mandibular positions during continuous phonation of the five vowels [( a], [e], [i], [o], [u]) and the relationship between each position and the rest position were examined for 30 subjects (males, 23 to 35 years of age) using the mandibular kinesiograph. Each subject had a complete or nearly complete natural dentition with no marked occlusal abnormalities. The mandibular position during continuous phonation of the vowel [i] appeared stable and was closely related to the rest position. It is thus suggested that the use of continuous [i] phonation is a viable method for determining the occlusal vertical dimension.

Adult↗

PubMed1992

Phonation and swallowing considerations in pediatric laryngotracheal reconstruction.

Experience with laryngotracheal reconstruction (LTR) has resulted in and continues to yield modifications and refinements in approach and technique with the goal to restore and maintain total laryngeal function. In addition to airway obstruction, the laryngeal functions of phonation and swallowing also may be affected by the underlying injury as well as by procedures designed to enlarge the airway. This paper discusses various problems encountered with phonation and swallowing in pediatric patients who underwent LTR and postoperative patients who were seen during the year July 1, 1990, through June 30, 1991. Phonation problems became apparent as long-term difficulties that persisted after tracheotomy decannulation. Swallowing was frequently a short-term perioperative problem while a stent was in place following LTR. The approaches and techniques that have been employed to treat, minimize, and prevent these problems are discussed.

Adolescent↗

PubMed1979

Acoustic qualities of phonation in young hearing-impaired children.

Monosyllables were recorded from a group of 24 hearing-impaired and 6 normal-hearing children between three to six years of age. Tokens of the syllables /ba/ and /bo/ were placed on listening tapes and a panel of 10 experienced listeners made ratings of relative voice quality. The phonation samples were subjected to both a gross (spectrographic) and a fine (computer-aided) acoustic analysis. The following acoustic characteristics were examined: (1) mean fundamental frequency, (2) duration, (3) mean period-to-period changes in intensity and in fundamental frequency, (4) spectral energy ratio above and below 1000 Hz, and (5) intonation contour. The type of intonation contour appeared to be the most important characteristic separating the better from the poorer deaf speakers. The hearing-impaired subjects produced four different types of deviant intonation contours. In addition, two abnormalities of phonation, diplophonia and breathiness, are described.

Child↗

PubMed1992

Increase in translaryngeal resistance during phonation in rheumatoid arthritis.

Laryngeal involvement by RA is a common finding, but there have been no studies of laryngeal function in RA patients. This study was undertaken to determine if patients with rheumatoid arthritis have functional abnormalities of the upper airway during phonation which may be the result of synovitis of the laryngeal joints caused by RA. Translaryngeal resistance was measured in six patients with RA and six matched control subjects using an interrupter method to measure PSG and V during vocalization. Patients with RA had a higher R (65.0 +/- 8.15 cm H2O/L/s) than control subjects (38.4 +/- 7.43 cm H2O/L/s [p less than 0.05]). This was the consequence of lower V rates during phonation at similar PSG. We conclude that abnormalities of the larynx in RA patients are common and cause measurable physiologic abnormalities.

Adult↗

PubMed1992

Brain stimulation-induced changes of phonation in the squirrel monkey.

In 11 squirrel monkeys (Saimiri sciureus), the brain stem was systematically explored with electrical brain stimulation for sites affecting the acoustic structure of ongoing vocalization. Vocalization was elicited by electrical stimulation of different brain structures. A severe deterioration of the acoustical structure of vocalization was obtained during stimulation of the caudoventral part of the periaqueductal grey, lateral parabrachial area, cortico-bulbar tract, nucl. ambiguus and surrounding reticular formation, facial nucleus, hypoglossal nucleus, solitary tract nucleus and along the fibres crossing the midline at the level of the hypoglossal nucleus. It is suggested that these structures are part of, or at least have direct access to, the motor coordination mechanism of phonation. Complete inhibition of phonation was obtained from the raphe and raphe-near reticular formation.

Animals↗

PubMed1978

A radiographic study of tongue posture at rest and during the phonation of /s/ in class III malocclusion.

In this investigation a group of individuals with Angle Class III malocclusions were studied radiographically to determine their tongue posture at rest and during phonation of /s/. Their speech and hearing was also evaluated. All of the subjects had normal hearing, while eleven of the twelve in the group showed some degree of sibilant distortion. At rest, these Class III subjects demonstrated a tongue posture that was lower than normal and more retruded. During the phonation of /s/ these individuals also demonstrated retrusion of the tongue in an apparent attempt to achieve a normal relationship of the tongue tip to the maxillary anterior teeth, an increased amount of mandibular depression, and a greater than normal distance between the tongue tip and the mandibular anterior teeth. Despite the compensatory movements exhibited by these individuals with Class III malocclusions, normal /s/ production was found in only one of the twelve subjects studied. This is in contrast to the successful compensations that result in normal /s/ production seen in a great number of individuals with a Class III, Division 1 malocclusion, as demonstrated by Subtelny, Mestre and Subtelny.

Adolescent↗

PubMed1976

The ability of stutterers and nonstutterers to initiate and terminate phonation during production of an isolated vowel.

This study tested the hypothesis that stutterers have difficulty initiating and terminating phonation independent of the acts of running speech and stuttering. Ten young adult stutterers served as the experimental group. They were matched as a group for age and sex with 10 normal speakers. Subjects from both groups were tested individually. The experimental task required that subjects start and stop phonation as quickly as possible upon hearing each member of a seried of 1000-Hz pure tones appear and then disappear. Subjects' vocalizations were permanently recorded on an optical oscillograph. Results showed that both groups improved (shortened) their voice initiation and termination times from the beginning to the end of the experiment. Typically, however, the stutterers were significantly slower than the control subjects on most of the temporal measures.

Adolescent↗

PubMed1979

Fundamental frequency perturbation observed in sustained phonation.

The middle segments of sustained phonations of /i/, produced by six male adults at fo's ranging from 98 to 298 Hz, were examined for cycle-to-cycle frequency perturbation. The voice samples were analyzed by a peak-picking fo analysis program (Horii, 1975). The results showed that, between 98 Hz and 210 Hz, mean jitter size decreased as the fo increased, whereas the corresponding jitter ratios remained relatively constant. Above about 210 Hz, mean jitter remained relatively constant and, consequently, the jitter ratio increased as fo increased. The problems of temporal resolution for vocal jitter studies, vowel-dependent jitter magnitude characteristics and various perturbation measures are discussed.

Adult↗

PubMed1979

A theoretical study of the effects of various laryngeal configurations on the acoustics of phonation.

Simulation of glottal volume flow and vocal fold tissue movement was accomplished by numerical solution of a time-dependent boundary value problem, in which nonuniform, orthotropic, linear, incompressible vocal fold tissue media were surrounded by irregularly shaped boundaries, which were either fixed or subject to aerodynamic stresses. Spatial nonuniformity of the tissues was of the layered type, including a mucosal layer, a ligamental layer, and muscular layers. Orthotropy was required to stabilized the vocal folds longitudinally and to accomodate large variations in muscular stress. Incompressibility and vertical motions at the golttis played an important role in producing and sustaining phonation. A nominal configuration for male fundamental speaking pitches was selected, and the regulation of fundamental frequency, intensity, average volume flow, and vocal efficiency was investigated in terms of variations around this nominal configuration. Parameters which were varied consisted of geometrical factors such as length, thickness, and depth, factors for shaping the glottis, as well as tissue elasticities, tissue viscosities, and subglottal pressure. Since nonlinear stress-strain properties were not included, subglottal pressure did not produce a pronounced effect upon fundamental frequency under these somewhat edealized conditions F0 rasing correlated strongly with increased tension in the ligament, and somewhat with increasing tension in the vocalis. F0 lowering correlated with increase in vocal fold length when the tensions were held constant, but not with increase in vocal fold thickness. Vocal intensity and efficiency are shown to have local maxima as the configurational parameters are varied one at a time. It appears that oral acoustic power output and vocal efficiency can be maximized by proper adjustments of longitudinal tension of nonmuscular (mucosal and ligamental) tissue layers in relation to muscular layers. Quantitative verification of the "body-cover" theory is therefore suggested, and several further implications with regard to control of the human larynx are considered.

Acoustics↗

PubMed1991

Experimental evidence in the in vivo canine for the collapsible tube model of phonation.

The in vivo canine model of the larynx was used to measure transglottic pressures and airflow during phonation. Conditions of supraglottal resistance were also simulated. Pressure drop-flow curves were compared with data on collapsible tubes. The in vivo in canine model of the larynx demonstrates a number of features similar to oscillation in collapsible tubes.

Air Movements↗

PubMed1991

Study of phonation in the excised canine larynx.

Previous studies have demonstrated that the laryngeal muscles responsible for pitch variation and vocal efficiency are the cricothyroid muscles, affecting longitudinal tension of the vocal folds, and the thyroarytenoid muscles, controlling the lateral stiffness of the vocal folds. Longitudinal tension in the vocal fold is easily simulated in the excised canine larynx. The effect of the thyroarytenoid muscle, however, has not been adequately analyzed. To simulate the effect of the thyroarytenoid muscle, small balloons were placed in the paraglottic space at the level of the vocal folds in 10 excised canine larynges. These balloons (Fogarty catheters) could be inflated in increments to simulate the effect of the thyroarytenoid muscle contraction in altering the lateral stiffness of the vocal fold. During phonation subglottic pressure, vocal fold longitudinal tension and balloon size were systematically varied. The photoglottographic and electroglottographic signals, sound intensity, and airflow rate were measured. Multiple regression analysis showed that sound intensity was directly related to subglottic pressure (p less than 0.001) and inversely related to balloon size (p less than 0.001). Vocal efficiency was directly related to subglottic pressure (p less than 0.001). Frequency of vibration was directly related to balloon size (p less than 0.05), vocal fold tension (p less than 0.001), and subglottic pressure (p less than 0.001). Open quotient was directly related to vocal fold tension (p less than 0.01) and inversely related to balloon size (p less than 0.001). Clinical implications of these results will be discussed.

Animals↗

PubMed1992

Vocal tract steadiness: a measure of phonatory and upper airway motor control during phonation in dysarthria.

Acoustic analyses of upper airway and phonatory stability were conducted on samples of sustained phonation to evaluate the relation between laryngeal and articulomotor stability for 31 patients with dysarthria and 12 non-dysarthric control subjects. Significantly higher values were found for the variability in fundamental frequency and format frequency of patients who have Huntington's disease compared with normal subjects and patients with Parkinson's disease. No significant correlations were found between format frequency variability and the variability of the fundamental frequency for any subject group. These findings are discussed as they pertain to the relationship between phonatory and upper airway subsystems and the evaluation of vocal tract motor control impairments in dysarthria.

Adult↗