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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↗
PubMed1990

[Image analysis of the contour of paralyzed vocal cord during phonation].

The development of digital radiography (DR) has made it possible to analyze the contour of the laryngeal soft tissue structures in more detail than the conventional screen-film method. We analyzed the contour of the paralyzed vocal cord during phonation using motion subtraction technique. Forty four patients with unilateral recurrent nerve palsy were examined. The images were obtained by means of frontal tomography of the larynx during quiet inspiration and normal (expiratory) phonation. Tomography during inspiratory phonation was also examined in ten patients who can perform it. The thickness of the slices was 5.0 mm. The authors found that the free margin of the paralyzed vocal cord shifted by the aerodynamic power along the direction of the air flow, i.e. it shifted to the cranial direction during normal phonation and to the caudal during inspiratory phonation. The displacement phenomenon of the paralyzed vocal cord was significantly correlated with the degree of vocal cord atrophy (p less than 0.01). The result would indicate that the aerodynamic power during phonation is one of the factors eliciting the higher position of the paralyzed vocal cord during phonation, in addition to its anatomical displacement due to abduction of the paralyzed arytenoid. This notion should be taken into consideration in selecting the surgical approach for the treatment of unilateral recurrent nerve palsy.

Adult↗
PubMed2004

[Phonation reconstruction and function assessment after total and near-total laryngectomy].

BACKGROUND & OBJECTIVE: Total laryngectomy is a common surgery pattern for treating laryngeal and hypopharyngeal cancer, but patients will lost phonation function after operation. This study was to retrospectively analyze usage of modified Amatsu, and modified Pearson operation in treating laryngeal and hypopharyngeal cancers, and to analyze phonation function by subjective and objective assessment. METHODS: Clinical data of 69 patients with laryngeal or hypopharyngeal cancer treated by total or near-total laryngectomy (modified Amatsu or modified Pearson operation) in our department from 1996 to 2003 were retrospectively analyzed. Phonation function of 69 patients was evaluated by acoustic analysis and Jiyan classification method, and compared with phonation quality of patients received vertical hemilaryngectomy (VHL) and healthy people. RESULTS: No patient appeared obvious aspiration. Four cases with post-operative radiotherapy all regained phonation function. The 3-year survival rate was 88% (22/25); 5-year survival rate was 80% (4/5). Results of acoustic assessment, and Jiyan classification method indicated that phonation function of patients received modified Amatsu or modified Pearson operation could meet daily requirements. CONCLUSIONS: Modified Amatsu and modified Pearson operations can be learnt and applied easily for phonation reconstruction after laryngectomy. They may be optional surgery patterns, especially modified Pearson operation.

Adult↗
PubMed1984

Maximum phonation time for children with normal voices.

Maximum phonation time (MPT) data were collected for 286 male and female children between the ages 3-6 and 17-11. Subjects sustained phonation of the vowel/a/for 14 consecutive trials. The influence of sex, age, and multiple trials on MPT was studied. The group mean MPT for the male subjects was significantly longer than for the female subjects. Generally, phonation time increased with age for both sexes. A definite monotonic increase in length of sustained phonation was not apparent across all age levels. Optimum MPT performance can be enhanced by using repeated trials, and by providing visual feedback and encouragement regarding depth of inhalation, verbal instructions and encouragement regarding increased phonation time, and visual feedback regarding length of sustained phonation prior to and during each trial. The large intra- and intersubject variability in MPT performance reported in this study prevents valid individual-group mean MPT comparisons. A more discriminatory clinical interpretation of MPT is necessary.

Adolescent↗
PubMed1997

Comparison of vocal tract formants in singing and nonperiodic phonation.

The skilled use of nonperiodic phonation techniques in combination with spectrum analysis has been proposed here as a practical method for locating formant frequencies in the singing voice. The study addresses the question of the degree of similarity between sung phonations and their nonperiodic imitations, with respect to both frequency of the first two formants as well as posture of the vocal tract. Using magnetic resonance imaging (MRI), linear predictive coding (LPC), and spectrum analysis, two types of nonperiodic phonation (ingressive and vocal fry) are compared with singing phonations to determine the degree of similarity/difference in acoustic and spatial dimensions of the vocal tract when these phonation types are used to approximate the postures of singing. In comparing phonation types, the close similarity in acoustic data in combination with the relative dissimilarity in spatial data indicates that the accurate imitations are not primarily the result of imitating the singing postures, but have instead an aural basis.

Acoustics↗
PubMed2002

Electroglottographic evaluation of gender and vowel effects during modal and vocal fry phonation.

Two unique characteristics of vocal fry register are the occurrence of multiple opening and closing phases occurring within one vibratory cycle and a similar vocal fundamental frequency (F0) between women and men. The present study tested the hypothesis that significant differences in glottal cycle symmetry exist between women and men during modal phonation, with no significant differences during vocal fry phonation. Consistent with previous studies of modal phonation, it was also hypothesized that a vowel effect would be apparent during vocal fry phonation. Five women and 5 men sustained modal and vocal fry phonations in four vowel contexts (/a, ae, u, i/). Vocal F0, duration of opening and closing phase, and contact symmetry (speed quotient) were derived from electroglottographic (EGG) waveforms. Both female and male speakers demonstrated significantly higher SQ values in vocal fry register than in their modal register, indicating a longer opening-phase duration per glottal cycle. Women demonstrated a significantly greater increase in SQ during vocal fry phonations than men, indicating greater asymmetry between opening and closing durations. The results confirmed that gender differences in vocal fold contact behavior not only exist during modal register but also during vocal fry register. No vowel effects on vocal fold contact behavior as inferred using the SQ measure were found for either modal or vocal fry registers. Possible contributing factors to multiple opening and closing phases occurring within a vibratory cycle are discussed.

Adult↗
PubMed2003

The self-to-other ratio applied as a phonation detector for voice accumulation.

A new method for phonation detection is presented. The method utilises two microphones attached near the subject's ears. Simplified, phonation is assumed to occur when the signals appear mainly in-phase and at equal amplitude. Several signal processing steps are added in order to improve the phonation detection, and finally the original signal is sorted in separate channels corresponding to the phonated and non-phonated instances. The method is tested in a laboratory setting to demonstrate the need for some of the stages of the signal processing and to examine the processing speed. The resulting sound file allows for measurement of phonation time, speaking time and fundamental frequency of the subject and sound pressure level of the subject's voice and the environmental sounds separately. The present implementation gives great freedom for adjustment of analysis parameters, since the microphone signals are recorded on DAT tape and the processing is performed off-line on a PC. In future versions, a voice accumulator based on this principle could be designed in order to shorten analysis time and thus make the method more appropriate for clinical use.

Equipment Design↗
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↗
PubMed2006

The pitch rise paradigm: a new task for real-time endoscopy of non-stationary phonation.

As standard stroboscopy is restricted to the recording of periodic vocal fold vibrations, observations of non-stationary laryngeal mechanisms demand real-time recording systems, the most advanced being the high-speed video technique. It allows the registration of laryngeal parameters during a variation of the fundamental frequency. The aim of this study was to compare amplitude and frequency parameters of vocal fold vibration during stationary and non-stationary phonation, i.e. a monotonous pitch rise. Twenty-nine young female adults with no incidence of voice disorders were examined while performing two different phonation tasks: sustained phonation with a constant frequency and a monotonous pitch rise. Endoscopic recordings and the acoustic signals were acquired simultaneously. Both acoustic and laryngeal parameters were derived for short time intervals of 17.8 ms for the constant pitch and pitch rise conditions. Instantaneous frequency, sound pressure level, vibratory amplitudes of the vocal folds and the type of glottal closure were compared. At the beginning of the pitch rise, the acoustic and laryngeal parameters were similar to the parameters that occurred within the sustained phonation conditions. In contrast, the laryngeal parameters at the middle and at the end of the pitch rise differed substantially from those during sustained phonation. For the first time, quantitative measures of the growing glottal chink and the vibration amplitude decrease during pitch increase could be taken. In general, the image evaluation of the pitch rise paradigm can be subdivided into the starting, the raising and the final phase. As each phase can be considered as quasi-stationary, existing software modules are capable of analysing the process by treating each phase separately. Hence, the pitch rise condition may be suitable for clinical examination to detect information of voice disturbances that cannot be visualized during sustained phonation.

Adolescent↗
PubMed1998

Long-term model of induced canine phonation.

Experimental induced phonation in the dog has been used in short-term studies by several investigators and has proved quite useful in laryngeal research. In this study a long-term canine phonation model is described that uses permanently implanted electrodes on the superior and recurrent laryngeal nerves. A serial induced phonation model has not been previously reported and is needed for laryngeal research in which voice results are a primary end point. Inexpensive, reliable, nontoxic electrodes were designed and fabricated. The laryngeal nerves were found to be quite susceptible to injury, necessitating a series of changes in electrode design. Electrode durability and laryngeal nerve viability improved with each design modification; the final design gave a recurrent laryngeal nerve viability rate of 100% at 6 weeks, 83% at 9 weeks, and 73% at 12 weeks. Induced phonation was successfully produced on a repeated basis by stimulating the recurrent laryngeal nerves while passing air through the larynx, in 22 (95.6%) of 23 animals. Stimulation of the superior laryngeal nerves increased vocal fold length and tension but was not required for phonation. Technical aspects of chronic implantation and stimulation of the laryngeal nerves are discussed. The development and successful long-term implantation of electrodes on the laryngeal nerves and their use in repeated induced phonation have not been reported previously.

Animals↗
PubMed1981

CT in carcinoma of the larynx and pyriform sinus: value of phonation scans.

The structural and functional information obtained from CT performed during quiet breathing and phonation of the letter E was investigated in 25 patients with carcinoma of the larynx or pyriform sinus. Significant additional information was obtained from the phonation scans in all patients. In 16 patients, vocal cord dysfunction was found on the phonation scans. In 14 patients, phonation CT demonstrated an abnormal aryepiglottic fold better than CT during quiet breathing. A pyriform sinus was distorted or displaced in 11 patients and CT during phonation was more accurate than laryngoscopy or CT during quiet breathing in detecting abnormalities deep to this region. CT scans were the most accurate method of detecting tumor extension into the subglottic space, and into the preepiglottic space; each extension was seen in seven patients. Thyroid cartilage destruction was detected only by CT in six patients. CT scans during phonation should be an integral part of laryngeal CT and in conjunction with laryngoscopy could possibly replace laryngography for the evaluation of patients with laryngeal carcinoma.

Arytenoid Cartilage↗
PubMed1993

[Laryngeal control mechanisms during respiration and phonation analyzed by excitability changes of laryngeal motoneurons in decerebrate cats].

Laryngeal motoneurons (LMNs) innervating the intrinsic laryngeal muscles also control glottal movements such as swallowing, respiration and phonation. The present study was performed on decerebrate cats to clarify the laryngeal control mechanisms during respiration and phonation using extracellular single unit recordings from the nucleus ambiguus. First, functional differences among LMNs during the respiratory phases were investigated by analysis of the activity of LMNs innervating laryngeal adductor (TA-LCA: thyroarytenoid-lateral cricoarytenoid) or abductor (PCA: posterior cricoarytenoid) muscles; Second, laryngeal control mechanisms during phonation were investigated by the analysis of neural activity of TA-LCA motoneurons during vocal fold vibration elicited by a constant air flow through the glottis. In both cases, motoneuronal excitability changes were expressed by measuring fluctuation of peak latencies of action potentials antidromically elicited by selective stimulation of the recurrent nerve or its peripheral branch. In 14 out of 24 TA-LCA motoneurons, neuronal excitability was increased during the expiratory phase, whereas in the remaining 10, it was increased during the later half of the inspiratory and the early half of the expiratory phase. On the other hand, 9 out of 13 PCA motoneurons showed increased neuronal excitability during the end of the expiratory and the beginning of the inspiratory phase, while the remaining 4 showed increased excitability during the inspiratory phase. These results suggest that there are functional differences among the homogeneous laryngeal motoneurons. In seven TA-LCA motoneurons, neuronal excitability was decreased by vocal fold vibration elicited by phonation throughout the whole respiratory cycle. On the other hand, when the bilateral superior laryngeal nerves were cut, neuronal excitability was increased during phonation throughout the whole respiratory cycle. These results indicate that TA-LCA motoneurons receive inhibitory inputs from the superior laryngeal nerve and excitatory inputs from the recurrent laryngeal nerve during the vocal fold vibration elicited by phonation.

Animals↗
PubMed2001

Inducing vocal register transition in an in vivo evoked phonation canine model.

BACKGROUND AND PURPOSE: The nature of vocal registers is still a subject of controversy. The purpose of this study was to demonstrate the induction of timbre transition of vocal register in an in vivo evoked phonation canine model and thereby confirm vocal register transition as a laryngeal event. MATERIALS: A canine midbrain stimulation evoked phonation model was used in this study. To repeat a low-pitched evoked phonation in the model, the low activity of the thyroarytenoid (TA) muscle and coordinate actions of other intrinsic laryngeal muscles were kept in a consistent condition by stimulating the same midbrain point with the same electric current intensity at the same timing in the respiratory cycle. The cricothyroid (CT) muscle was activated with an electrical current delivered directly to the muscle during the evoked phonation. Under constant subglottal pressure, CT muscle activity was varied while changes in vocal register of the evoked phonation were monitored. RESULTS: The fundamental frequency (F0) of the evoked phonation increased as the stimulating current to the CT muscle increased. In addition to the increase in F0, data collected from six animals demonstrated that timbre register transition was induced by a stepwise increase of current to the CT muscle. The abrupt escalation of F0 and sudden change in sound quality, which could be verified perceptually, manifested the register transition. Frequency spectrum analysis showed that the sound in the modal register contained abundant harmonics that were different from those of the sound in the falsetto register, which contained fewer harmonics. CONCLUSION: The results of this study indicated that intrinsic laryngeal muscles (especially CT and TA muscle interactions) regulate timbre-register transition in a canine model.

Animals↗
PubMed2002

[A long-term observation of 48 cases of tracheoesophageal shunt phonation by the anastomosis of the membranous portion of the tracheal section with the anterior wall of esophagus after total laryngectomy].

OBJECTIVE: To study the long-term efficacy of tracheoesophageal (TE) shunt phonation by the anastomosis of the membranous portion of the tracheal section with the anterior wall of esophagus after total laryngectomy. METHODS: A questionnaire was designed to follow 48 patients with rehabilitated speech and swallow functions by the above approach. The qualities of phonation and speech, and the degree of aspiration evaluated, together with the survival rate and complications statistically analyzed. RESULTS: The speech level of 35 laryngectomees was similar to the normal laryngeal speech level. Thirty-five cases had longer maximal phonation time and hearing distance and higher speech intelligibility. Other 5 laryngectomees had less effective phonation, but higher speech intelligibility. The total effective rate was 83.3% (40/48). The speech fluency in 40 laryngectomees was not as good as that in the normal people. Forty percent laryngectomees(16/40) had slight liquid food aspiration which did not influence normal eating. Eight patients(8/48) failed to speak and no liquid aspiration occurred after the operation. The effective rate was affected obviously by neck infection and pharyngeal fistula formation. The survival rate was similar to those with single total laryngectomy. CONCLUSIONS: The TE shunt phonation had the advantages of simple, one-stage operation and high success rate. Some laryngectomees had slight liquid food aspiration, but would not influence normal eating. So this TE shunt phonation operation may be useful during laryngeal surgery.

Adult↗
PubMed2004

Fragments of a Greek Trilogy: impact on phonation.

This study documents the vocal characteristics of an actor before and after a series of eight performances involving extended voice use. The hypothesis was that this type of extended voice use would result in symptoms of vocal abuse and that damage to the actor's voice would be evident in measures made after the performance series. Three pre-performance and three post-performance speech samples were gathered and analyzed using the CSL and Visipitch II. Measurements taken included maximum phonational range; maximum sustained phonation; fundamental frequency during reading; maximum intensity levels; sound pressure levels for soft, moderate, and loud productions of sustained /a/; and perturbation including jitter, shimmer, harmonics-to-noise ratio, and an s/z ratio. Pre- and post-performance samples of the "Rainbow passage" and sustained vowel phonation were rated by a group of blinded listeners that included professional voice trainers and speech pathologists. In addition, sample lines from the performance were played for the listeners to judge whether this technique would result in symptoms of vocal abuse. Eleven out of 12 professional voice trainers rated that this technique would result in symptoms of vocal abuse. The data revealed post-performance improvement in phonational range, maximum intensity levels, perturbation measures, and s/z ratio. Measures of maximum sustained phonation, fundamental frequency, and sound pressure levels remained stable. Videoendoscopy revealed normal function of the larynx and vocal folds.

Adult↗
PubMed2003

Vocal warm-up increases phonation threshold pressure in soprano singers at high pitch.

Vocal warm-up is thought to optimize singing performance. We compared effects of short-term, submaximal, vocal warm-up exercise with those of vocal rest on the soprano voice (n = 10, ages 19-21 years). Dependent variables were the minimum subglottic air pressure required for vocal fold oscillation to occur (phonation threshold pressure, Pth), and the maximum and minimum phonation fundamental frequency. Warm-up increased Pth for high pitch phonation (p = 0.033), but not for comfortable (p = 0.297) or low (p = 0.087) pitch phonation. No significant difference in the maximum phonation frequency (p = 0.193) or minimum frequency (p = 0.222) was observed. An elevated Pth at controlled high pitch, but an unchanging maximum and minimum frequency production suggests that short-term vocal exercise may increase the viscosity of the vocal fold and thus serve to stabilize the high voice.

Adult↗
PubMed1993

Phonatory control in male singing: a study of the effects of subglottal pressure, fundamental frequency, and mode of phonation on the voice source.

This article describes experiments carried out in order to gain a deeper understanding of the mechanisms underlying variation of vocal loudness in singers. Ten singers, two of whom are famous professional opera tenor soloists, phonated at different pitches and different loudnesses. Their voice source characteristics were analyzed by inverse filtering the oral airflow signal. It was found that the main physiological variable underlying loudness variation is subglottal pressure (Ps). The voice source property determining most of the loudness variation is the amplitude of the negative peak of the differentiated flow signal, as predicted by previous research. Increases in this amplitude are achieved by (a) increasing the pulse amplitude of the flow waveform; (b) moving the moment of vocal fold contact earlier in time, closer to the center of the pulse; and (c) skewing the pulses. The last mentioned alternative seems dependent on both Ps and the ratio between the fundamental frequency and the first formant. On the average, the singers doubled Ps when they increased fundamental frequency by one octave, and a doubling of the excess Ps over threshold caused the sound pressure level (SPL) to increase by 8-9 dB for neutral phonation, less if mode of phonation was changed to pressed. A shift of mode of phonation from flow over neutral to pressed was associated with a reduction of the peak glottal permittance i.e., the ratio between peak transglottal airflow to Ps. Flow phonation had the most favorable relationship between Ps and SPL.

Air Pressure↗
PubMed1999

The effects of rehydration on phonation in excised canine larynges.

Experiments using excised canine larynges were conducted to study the restoration of vocal efficiency in dehydrated larynges. Excised larynges were dehydrated with warm, dry air to the point that airflow through the approximated vocal folds would not entrain the folds to produce phonation. The dehydrated vocal folds were then bathed in a saline solution. The rehydrated larynges were then remounted on the bench apparatus that enabled phonation with a constant humidified airflow, and measurements were made of phonation threshold pressure, glottal airflow, and amplitude. Hydration resulted in significantly increased efficiency and decrease in phonation threshold pressure. The findings confirm clinical impressions that hydration is critical in the physiology of normal phonation.

Animals↗