Investigation of Anti-Hyaluronidase Treatment on Vocal Fold Wound Healing

SUMMARY: Phytochemical constituents of medicinal plants demonstrate inhibition of tissue and bacterial hyaluronidase. Echinacoside is a caffeoyl conjugate of Echinacea with known anti-hyaluronidase properties. The purpose of this study was to investigate the wound healing effects of Echinacea on vocal fold wound healing and functional voice outcomes. Pig animal model. Methods: Vocal fold injury was induced in 18 pigs by unilateral vocal fold stripping. The uninjured vocal fold served as control. Three groups of six pigs randomly received a topical application of 300, 600, or 1,200 mg of standardized Echinacea on the injured side. Animals were euthanized after 3, 10, and 15 days of wound healing. Phonation threshold pressure and vocal economy measurements were obtained from excised larynges. Treatment outcomes were examined by comparing the animals receiving treatment with a set of 19 untreated and 5 historical controls. Treatment effects on wound healing were evaluated by histologic staining for hyaluronan and collagen. Treated larynges revealed improved vocal economy and phonation threshold pressure compared with untreated larynges. Histologically, treated vocal folds revealed stable hyaluronan content and no significant accumulation of collagen compared with control. Findings provide a favorable outcome of anti-hyaluronidase treatment on acute vocal fold wound healing and functional measures of voice.     

Glottic Characteristics and Voice Complaint in the Elderly

This study evaluated the relationship between voice complaint and deviant vocal fold status with special regard to presbylarynx, in patients aged more than 60 years, with pharyngeal-laryngeal complaint. The material consisted of clinical histories and images obtained by laryngoscopies from protocols from the Larynx Institute-INLAR, Sao Paulo, Brazil, of 210 patients, 88 men and 122 women, aged more than 60 years, who had sought otorhinolaryngologic treatment. Indicative glottic characteristics of the presbylarynx, such as vocal fold bowing, prominence of vocal processes, and spindle-shaped glottic chink, were analyzed. The increase in mass, leukoplakia, and other vocal fold alterations, distinct from these two, grouped as miscellaneous, as well as the presence or absence of voice complaint were also analyzed. Vocal fold bowing, prominence of vocal processes, and spindle-shaped glottic chink showed a strong correlation among each other. The presence of presbylarynx was accompanied by less voice complaint than the presence of vocal fold mucosa alterations, which in turn are more common where an absence of presbylarynx exists.     

Measures of spectral slope using an excised larynx model

Spectral measures of the glottal source were investigated using an excised canine larynx (CL) model for various aerodynamic and phonatory conditions. These measures included spectral harmonic difference H1-H2 and spectral slope that are highly correlated with voice quality but not reported in a systematic manner using an excised larynx model. It was hypothesized that the acoustic spectra of the glottal source were significantly influenced by the subglottal pressure, glottal adduction, and vocal fold elongation, as well as the resulting vibration pattern. CLs were prepared, mounted on the bench with and without false vocal folds, and made to oscillate with a flow of heated and humidified air. Major control parameters were subglottal pressure, adduction, and elongation. Electroglottograph, subglottal pressure, flow rate, and audio signals were analyzed using custom software. Results suggest that an increase in subglottal pressure and glottal adduction may change the energy balance between harmonics by increasing the spectral energy of the first few harmonics in an unpredictable manner. It is suggested that changes in the dynamics of vocal fold motion may be responsible for different spectral patterns. The finding that the spectral harmonics do not conform to previous findings was demonstrated through various cases. Results of this study may shed light on phonatory spectral control when the larynx is part of a complete vocal tract system.     

Mechanical and dynamic aspects of voice production as related to voice therapy and phonosurgery

Laryngeal framework surgery can change the position and tensionof the vocal folds safely without direct surgical intervention in the vocal fold proper. Some 23 years of experience with phonosurgery have proved its usefulness in treating dysphonia related to unilateral vocal fold paralysis, vocal fold atrophy, and pitch-related dysphonias. Meanwhile, much information about the mechanism of voice production has been obtained through intraoperative findings of voice and fiberscopic examination of the larynx . Based on such knowledge together with information obtained through model experiments, the human vocal organ was reconsidered mainly from the mechanical view point, and the roles of voice therapy and singing pedagogy were discussed in relation to phonosurgery. The vocal organ may not be an ideal musical organ and is rather vulnerable, but its potential is enormous.     

Strobovideolaryngoscopic Findings in Singing Teachers

Professional voice users often present to otolaryngologists and laryngologists with specific voice complaints. The contributions of pathologic lesions to the patients' vocal complaints are not always clear on examination, and often, premorbid examinations of the larynx are not available for review. This study examines the incidence of laryngeal pathology among singing teachers. At a national convention of singing teachers, volunteers were recruited for a "free strobovideolaryngoscopic examination." All volunteers completed a detailed questionnaire of their vocal and medical history and underwent strobovideolaryngoscopic examination. Strobovideolaryngoscopic examinations were completed in 20 volunteers, 7 of whom had voice complaints and 13 of whom perceived their voices to be normal. Vocal fold masses were common among the asymptomatic singing teachers. Evidence of reflux laryngitis was a common finding among both symptomatic and asymptomatic singing teachers. Asymmetries in vocal fold hypomobility were more common among those with voice complaints than was the presence of vocal fold masses in the population studied.     

The False Vocal Folds: Shape and Size in Frontal View During Phonation Based on Laminagraphic Tracings

The geometry of the false vocal fold region during phonation is important to the understanding of the aerodynamics and acoustics of voice. The shape and dimensions of this region during phonation were estimated using laminagraphic tracings of the larynx. Laminagrams from two previous studies, one with non-singer subjects (Experiment I, Hollien and Colton, 1969) and the other with singers (Experiment II, Wilson, 1972), were traced, photocopied, and measured. Statistical analysis showed significantly greater false vocal fold height in males than females for both experiments. The false vocal fold gap was also significantly greater in males than females for Experiment II, but reached only borderline significance for Experiment I. For each gender, most of the linear measures were greater in Experiment I when compared to Experiment II; these differences may be passive in nature (due to actual differences in subject size) or active (due to muscle contraction that displaced the false vocal folds during singing).     

Laryngeal and pharyngeal behavior in countertenor and baritone singing—A videofiberscopic study

Changes in vocal tract configuration during singing were studied in four semiprofessional countertenors and one professional bass-baritone, by means of fiberoptic laryngoscopy. All of the countertenors showed a marked narrowing of the lower pharynx with increasing pitch when they used their countertenor voice (CT voice) but only a slight narrowing when using their baritone voice (B voice). The bass-baritone's pharynx remained unchanged with increasing pitch. Increasing loudness gave a widening of the pharynx in three of the four countertenors' CT voices, whereas no change was observed for the countertenors' B voices or for the bass-baritone voice. Vocal fold length seemed to decrease in one countertenor's B voice and in the bass-baritone with increasing loudness. Thus, the countertenors in this study exhibit several characteristic patterns of vocal tract gestures in countertenor voice that differ from both their own baritone voices and from the bass-baritone.     

Standardized laryngeal videostroboscopic rating: Differences between untrained and trained male and female subjects, and effects of varying sound intensity, fundamental frequency, and age

To determine the influence of the factors gender, vocal training, sound intensity, pitch, and aging on vocal function, videolaryngostroboscopic images of 214 subjects, subdivided according to gender and status of vocal training, were evaluated by three judges with standardized rating scales, comprising aspects of laryngeal appearance (larynx/pharynx ratio; epiglottal shape; asymmetry arytenoid region; compensatory adjustments; thickness, width, length, and elasticity of vocal folds) and glottal functioning (amplitudes of excursion; duration, percentage, and type of vocal fold closure; phase differences; location of glottal chink). The video registrations were made while the subjects performed a set of phonatory tasks, comprising the utterance of the vowel /i/ at three levels of both fundamental frequency and sound intensity. Analysis of the rating scales showed generally sufficient agreement among judges. With the exception of more frequently observed complete closure and lateral phase differences of vocal fold excursions in trained subjects, no further differences were established between untrained and trained subjects. With an α level of p = 0.005, men differed from women with respect to laryngeal appearance (larynx/pharynx ratio, compensatory adjustments, and the presence of omega and deviant-shaped epiglottises), and their vocal folds were rated thicker in the vertical dimension, smaller in the lateral dimension, longer, and more tense, with smaller amplitudes of excursion during vibration. Glottal closure in male subjects was rated more complete, but briefer in duration. Significant effects of the factors pitch, sound intensity, and age on vocal fold appearance and glottal functioning were ascertained. Awareness of the influence of these factors, as well as the factor gender, on the rated scales is essential for an adequate evaluation of laryngostroboscopic images.     

Dual Intracordal Unilateral Vocal Fold Cysts: A Perplexing Diagnostic and Therapeutic Challenge

SUMMARY: A 52-year-old professional voice user, a director of international sales and marketing and sports coach, described a 40-year history of severe hoarseness, with recent progressive dysphonia. He could not be heard on a cell phone and was unable to raise the volume or intensity of his voice. Strobovideolaryngoscopy revealed a perplexing set of dual intracordal lesions in the left vocal fold and a posterior glottal gap. The amplitude and magnitude of the left vocal fold mucosal waves were barely perceptible and were severely decreased in the right. There was marked phase asymmetry and aperiodicity bilaterally. A computed tomography scan of the neck with contrast and multiplanar reformatted reconstructions and a magnetic resonance imaging (MRI) of the neck with and without contrast revealed the nodular appearing masses of the left vocal fold without any definite evidence of paraglottic or supraglottic extension and no cervical lymphadenopathy. He had a hyperfunctional larynx with laryngopharyngeal reflux and chronic reflux laryngitis. Voice restoration required antireflux therapy, voice therapy, and phonomicrosurgical excision of the lesions. One benign epidermoid malformation cyst was lined by squamous epithelium. The second was a retention cyst lined with cuboidal epithelium. Finally, after 40 years, he has a normal voice.     

Vocal fold augmentation with injectable calcium hydroxylapatite: short-term results.

Symptoms of unilateral vocal fold paralysis are improved significantly by augmenting the paralyzed vocal fold via vocal fold injection. In this trial, augmentation with a new calcium hydroxylapatite implant was evaluated. In addition, two different phonosurgical injection techniques were used, and these procedures were compared for accuracy and reliability. A total of 11 terminal patients with unilateral vocal fold paralysis underwent vocal fold injection with calcium hydroxylapatite. Efficacy of the implant was evaluated by comparing results from the Voice Handicap Index (VHI) and mean airflow measurements before and 6 months after injection. Surgeon evaluations determined the comparative benefits of either endoscopic direct vocal fold injection or percutaneous vocal fold injection. Six-month data were obtained for a cohort of five patients. VHI scores improved for all five patients available for full evaluation and four of the five achieved improvements in mean airflow rates. Of the remaining patients, one later had a medialization laryngoplasty, two died from their terminal diseases before the 6-month follow-up, and two of the remaining three reported satisfaction with the results via telephone follow-up. Vocal fold injection via endoscopic, direct laryngoscopy was found to be a more reliable procedure for vocal fold injection than percutaneous injection. Slight overinjection (10% to 15%) was found to provide optimum results. Vocal fold injection of calcium hydroxylapatite for unilateral vocal fold paralysis improved voice quality and reduced mean airflow rates in this patient group with short-term results. Long-term studies are needed to confirm the durability of these findings.     

A critical view of the yawn-sigh as a voice therapy technique

The purpose of this study was to take a critical look at a voice therapy technique known as the yawn-sigh. The voiced sigh as an approach in voice therapy has had increased use in recent years, particularly with problems of vocal hyperfunction. In this study, the physiology of the yawn-sigh was studied with video nasoendoscopy in eight normal subjects; their taped voices were also studied acoustically for possible fundamental frequency and formant changes in producing selected vowels under normal and sigh conditions. Although each subject was given a model by the examiner of a yawn-sigh, one of the eight subjects could not produce a true yawn-sigh. Endoscopic findings for seven of the eight subjects performing the yawn-sigh demonstrated retracted elevation of the tongue, a lower positioning of the larynx, and a widened pharynx. Acoustic analyses for the seven subjects producing the sigh found a marked lowering of the second and third formants. Implications for using the yawn-sigh in voice therapy are given, such as using a modified “silent” yawn-sigh, as an easy method for producing greater vocal tract relaxation.     

Dependence of phonation threshold pressure on vocal tract acoustics and vocal fold tissue mechanics

Analytical and computer simulation studies have shown that the acoustic impedance of the vocal tract as well as the viscoelastic properties of vocal fold tissues are critical for determining the dynamics and the energy transfer mechanism of vocal fold oscillation. In the present study, a linear, small-amplitude oscillation theory was revised by taking into account the propagation of a mucosal wave and the inertive reactance (inertance) of the supraglottal vocal tract as the major energy transfer mechanisms for flow-induced self-oscillation of the vocal fold. Specifically, analytical results predicted that phonation threshold pressure (Pth) increases with the viscous shear properties of the vocal fold, but decreases with vocal tract inertance. This theory was empirically tested using a physical model of the larynx, where biological materials (fat, hyaluronic acid, and fibronectin) were implanted into the vocal fold cover to investigate the effect of vocal fold tissue viscoelasticity on Pth. A uniform-tube supraglottal vocal tract was also introduced to examine the effect of vocal tract inertance on Pth. Results showed that Pth decreased with the inertive impedance of the vocal tract and increased with the viscous shear modulus (G") or dynamic viscosity (eta') of the vocal fold cover, consistent with theoretical predictions. These findings supported the potential biomechanical benefits of hyaluronic acid as a surgical bioimplant for repairing voice disorders involving the superficial layer of the lamina propria, such as scarring, sulcus vocalis, atrophy, and Reinke's edema.     

The use of topical anesthetic in videostroboscopic examination of the larynx

The use of topical anesthetic spray in the oropharynx to reduce excessive gag reflex and permit endoscopic videostroboscopy of the larynx is a common clinical practice. However, clinical observations and some studies have indicated that such use may alter physiological status and result in adverse changes in laryngeal activity. This study examined possible effects of topical anesthetic on a wide range of laryngeal activity assessed with videostroboscopy. Laryngeal activity of 10 young adults with normal larynges was evaluated with and without lidocaine. Results indicated that the use of topical anesthetic to reduce the gag reflex did not affect vocal performance and may have examination benefits     

Perceptual and Acoustic Assessment of Voice Pathology and the Efficacy of Endolaryngeal Phonomicrosurgery

Values for acoustic voice measurements were obtained from 88 normal individuals and 98 pathological cases of mass lesions of vocal fold and 50 cases of unilateral vocal fold paralysis. Overall, all items reflecting perturbations of pitch and amplitude as well as glottal noise were significantly higher in the groups of patients compared with the normal group. The measurement of normalized noise energy (NNE) was found to be an optimum parameter for discrimination of normal/abnormal voices. The voices of patients with vocal fold nodules and vocal fold polyps were analyzed before endolaryngeal phonomicrosurgery (EPM) and 2 weeks after. Statistically significant (p < 0.01) improvement was achieved both in perceptual and acoustic analysis. EPM resulted in a significant decrease of mean jitter, shimmer, and NNE. Clinically, these measures provided documentable and measurable evidence of vocal function and were helpful for comparing patients with normal speakers. They also were useful for a thorough documentation of patient's voice pathology and for evaluation of the presurgical and postsurgical voice status.     

Physiological aspects of a vocal exercise

The physiological aim of vocal exercises is mostly understood in intuitive terms only. This article presents an attempt to document the phonatory behavior induced by a vocal exercise. An elevated vertical position of the larynx is frequently associated with hyperfunctional phonatory habits, presumably because it induces an exaggerated vocal fold adduction. Using the multichannel electroglottograph (MEGG), the laryngeal position was determined in a group of subjects who performed a voice exercise that contained extremely prolonged versions of the consonant /b:/. This exercise is used by the coauthor (N.E.) as part of a standard vocal exercise program. Two of the seven subjects were dysphonic phonastenic patients, and the rest were normal trained or untrained persons. Different attempts to calibrate the MEGG confirmed a linear relationship with larynx height, provided electrode positioning was correct. The results showed that the exercise induced substantial vertical displacements of the larynx. Comparison with larynx height during voicing of other consonants showed that the /b/, in particular, tended to lower the larynx.     

Japanese version of voice handicap index for subjective evaluation of voice disorder

Recently, the Voice Handicap Index (VHI), developed in the United States, has been highlighted as a means to assess a patient's perceptions of the severity of his or her voice disorder. The VHI is based on a self-administered questionnaire that quantifies the degree of a patient's disability related to his/her voice disorder. The questionnaire was translated into Japanese and applied to Japanese patients with various kinds of disordered voice or dysphonia. The results were analyzed and the usefulness discussed. In this study, 546 patients (281 males and 265 females) were included. Mean VHI scores were 36.2/120 in males and 44.1/120 in females. In the male patients, VHI scores were the highest among teens. However, VHI scores did not vary with age in the female patients. Patients with vocal fold paralysis, functional dysphonia, psychological dysphonia, and spasmodic dysphonia showed relatively high VHI scores, whereas those with laryngeal granuloma and laryngopharyngeal reflux disease showed low scores. In most diseases, functional and physiological scores were higher than emotional scores. In any treated patients, those with vocal nodule, vocal polyp, polypoid vocal fold, and recurrent laryngeal nerve paralysis, VHI scores decreased after therapeutic intervention. These findings suggest that the Japanese VHI is a useful tool for monitoring a patient's psychological status, choosing appropriate treatment, and assessing the therapeutic outcome.     

Voice source characteristics in Mongolian "throat singing" studied with high-speed imaging technique, acoustic spectra, and inverse filtering.

Mongolian "throat singing" can be performed in different modes. In Mongolia, the bass-type is called Kargyraa. The voice source in bass-type throat singing was studied in one male singer. The subject alternated between modal voice and the throat singing mode. Vocal fold vibrations were observed with high-speed photography, using a computerized recording system. The spectral characteristics of the sound signal were analyzed. Kymographic image data were compared to the sound signal and flow inverse filtering data from the same singer were obtained on a separate occasion. It was found that the vocal folds vibrated at the same frequency throughout both modes of singing. During throat singing the ventricular folds vibrated with complete but short closures at half the frequency of the true vocal folds, covering every second vocal fold closure. Kymographic data confirmed the findings. The spectrum contained added subharmonics compared to modal voice. In the inverse filtered signal the amplitude of every second airflow pulse was considerably lowered. The ventricular folds appeared to modulate the sound by reducing the glottal flow of every other vocal fold vibratory cycle.     

Functional Analysis of Voice Using Simultaneous High-Speed Imaging and Acoustic Recordings

We present a comprehensive, functional analysis of clinical voice data derived from both high-speed digital imaging (HSDI) of the larynx and simultaneously acquired acoustic recordings. The goals of this study are to: (1) correlate dynamic characteristics of the vocal folds derived from direct laryngeal imaging with indirectly acquired acoustic measurements; (2) define the advantages of using a combined imaging/acoustic approach for the analysis of voice condition; and (3) identify new quantitative measures to evaluate the regularity of the vocal fold vibration and the complexity of the vocal output -- these measures will be key to successful diagnosis of vocal abnormalities. Image- and acoustic-based analyses are performed using an analytic phase plot approach previously introduced by our group (referred to as 'Nyquist' plot). Fast Fourier Transform (FFT) spectral analyses are performed on the same data for a comparison. Clinical HSDI and acoustic recordings from subjects having normal and specific voice pathologies, including muscular tension dysphonia (MTD) and recurrent respiratory papillomatosis (RRP) were analyzed using the Nyquist plot approach. The results of these analyses show that a combined imaging/acoustic analysis approach provides better characterization of the vibratory behavior of the vocal folds as it correlates with vocal output and pathology.     

Bifurcations and chaos in register transitions of excised larynx experiments

Experimental data from an excised larynx are analyzed in the light of nonlinear dynamics. The excised larynx provides an experimental framework that enables artificial control and direct observation of the vocal fold vibrations. Of particular interest in this experiment is the coexistence of two distinct vibration patterns, which closely resemble chest and falsetto registers of the human voice. Abrupt transitions between the two registers are typically accompanied by irregular vibrations. Two approaches are presented for the modeling of the excised larynx experiment; one is the nonlinear predictive modeling of the experimental time series and the other is the biomechanical modeling (three-mass model) that takes into account basic mechanisms of the vocal fold vibrations. The two approaches show that the chest and falsetto vibrations correspond to two coexisting limit cycles, which jump to each other with a change in the bifurcation parameter. Irregular vibrations observed at the register jumps are due to chaos that exists near the two limit cycles. This provides an alternative mechanism to generate chaotic vibrations in excised larynx experiment, which is different from the conventionally known mechanisms such as strong asymmetry between the left and right vocal folds or excessively high subglottal pressure.