Measurement of formant frequencies and bandwidths in singing

That singers under certain circumstances adjust the articulation of the vocal tract (formant tuning) to enhance acoustic output is both apparent from measurements and understood in theory. The precise effect of a formant on an approaching (retreating) harmonic as the latter varies in frequency during actual singing, however, is difficult to isolate. In this study variations in amplitude of radiated sound components as well as supraglottal and subglottal (esophageal) pressures accompanying the vibrato-related sweep of voice harmonics were used as a basis for estimating the effective center frequencies and bandwidths of the first and second formants.     

The Relationship Between Chronic Cough and Paradoxical Vocal Fold Movement: A Review of the Literature

SUMMARY: Chronic cough (CC) and paradoxical vocal fold movement (PVFM) are debilitating conditions. PVFM has been given many labels, including vocal cord dysfunction, Munchausen's stridor, functional inspiratory stridor, nonorganic functional or psychogenic upper airway obstruction, factitious asthma, psychogenic stridor, emotional laryngeal wheezing, and episodic laryngeal dyskinesia. Although CC and PVFM have been considered separate entities in many reports, there is preliminary support for the notion that there may be an underlying link between these two conditions. Speech pathologists have become increasingly involved in the treatment of these patients and therefore need to understand the theoretical background of these disorders, the pathophysiological links between the two, and the impact of voice disorders on these populations. The aim of this article is to review the current literature on CC and PVFM from a speech pathology perspective to provide a model for defining and conceptualizing the disorders and to provide a framework for management and future research.     

Vocal Fatigue: Current Knowledge and Future Directions

Vocal fatigue is a complex multifaceted clinical phenomenon. Several hypotheses exist concerning its underlying mechanism, and a range of empirical studies have examined its manifestation. This article reviews the literature pertaining to the nature, underlying processes, and salient features of vocal fatigue. First, vocal fatigue is defined, its major symptoms are discussed, and hypotheses concerning its primary physiological and biomechanical mechanisms are considered. Second, studies of experimentally induced vocal fatigue in humans are evaluated. Third, research investigating the clinical and occupational manifestations of vocal fatigue is discussed. Fourth, directions for ongoing research in this area are offered.     

Correspondence of electroglottographic closed quotient to vocal fold impact stress in excised canine larynges

The purpose of this study was to explore the possible use of the electroglottographic closed quotient (EGG CQ) as a noninvasive estimate of vocal fold impact stress (SI). Two excised canine larynges were used. Each larynx was mounted and vocal fold oscillation was induced using a humidified air source. Twentyseven experimental trials were conducted for each larynx. Trials involved variations in vocal process gap, vocal fold elongation, and subglottic pressure. Simultaneous measures were made of vocal fold SI at the midpoint of the membranous vocal folds, and EGG CQ (dimensionless ratio). The results indicated that when threshold and saturation effects were excluded, the SI and the CQ were strongly related (linear correlation r = .83 and .96 for the two individual larynges, and .81 for the combined data). Within the region of linear relation, an increase of .15 in the CQ corresponded to about 1 kPa increase in SI for the combined data. Discussion focuses on possible clinical implications and the likely reasons for threshold and saturation phenomena.     

A comparison of the prevalence of vocal symptoms among teacher students and other university students

Studies focusing on different groups of students show that the prevalence of vocal symptoms and voice disorder vary depending on the study populations. A previous study of vocal symptoms and voice disorders among teacher students has shown that 20% of the students studying to become teachers in comprehensive schools and upper secondary schools reported frequently occurring vocal symptoms, ie, two symptoms or more occurring weekly or more often during the past year, and that most of these students had an organic voice disorder. This raised the question of whether other university students would also report similar, frequently occurring vocal symptoms. A questionnaire was distributed to 220 students of several faculties at the University of Turku, Finland. The results were compared with the results of a study of vocal symptoms reported by 175 students studying to become teachers. This comparison showed that students in general reported frequently occurring vocal symptoms, whereas the students studying to become teachers reported a greater number of frequently occurring symptoms than did other students at the university.     

Vocal Fold Wound Healing: A Review for Clinicians

SUMMARY: The basic science of wound healing is largely omitted from the curriculum of many voice clinicians. This fact is relatively disheartening as most therapeutic manipulation in the realm of laryngology and voice disorders deals with injured tissue. Therefore, the selection of therapeutic tasks for persons with vocal injury should ideally be informed by basic science in wound healing. Recently, several investigators have initiated lines of research to determine the course of vocal fold wound healing and the potential role of therapeutic agents, including behavioral agents. The current review seeks to provide a foundation of basic wound healing science and present the most current data regarding the wound healing process in the vocal folds.     

Effects of Vocal Training and Phonatory Task on Voice Onset Time

OBJECTIVES/HYPOTHESIS: The purpose of this study was to examine the temporal-acoustic differences between trained singers and nonsingers during speech and singing tasks. METHODS: Thirty male participants were separated into two groups of 15 according to level of vocal training (ie, trained or untrained). The participants spoke and sang carrier phrases containing English voiced and voiceless bilabial stops, and voice onset time (VOT) was measured for the stop consonant productions. RESULTS: Mixed analyses of variance revealed a significant main effect between speech and singing for /p/ and /b/, with VOT durations longer during speech than singing for /p/, and the opposite true for /b/. Furthermore, a significant phonatory task by vocal training interaction was observed for /p/ productions. CONCLUSIONS: The results indicated that the type of phonatory task influences VOT and that these influences are most obvious in trained singers secondary to the articulatory and phonatory adjustments learned during vocal training.     

The Evaluation of Benign Glottic Lesions: Rigid Telescopic Stroboscopy Versus Suspension Microlaryngoscopy

Rigid telescopic strobo-video-laryngoscopy (RTS) is a primary clinical assessment methodology in the office evaluation of benign glottic lesions. However, diagnostic observations can be made only at the time of suspension microlaryngoscopy (SML). The records of 100 consecutive patients undergoing microlaryngoscopy for benign glottic lesions were retrospectively reviewed. Nine of 100 patients were found to have additional glottic lesions during SML. Sixteen additional lesions were noted in these nine patients. Fifteen of 16 lesions were sulci and/or mucosal bridges. Forty-five percent (4/9) of the patients with additional lesions underwent a management change intraoperatively. Three patients underwent additional surgical dissection, and one underwent less dissection than was planned. The discrepancy in diagnosis between rigid telescopic strobo-video-laryngoscopy and suspension microlaryngoscopy highlights certain key points: (1) During office endoscopy, tangential views of the medial surface of the glottis limit the diagnostic sensitivity. (2) Sulci and mucosal bridges are most subject to this limitation. (3) Informed consent should address the potential need for a change in intraoperative management. It is advisable to discuss the possibility for dissection in both vocal folds, even if a unilateral lesion is observed in the office. (4) Microlaryngoscopy is the final diagnostic step in the evaluation of glottic pathology. Meticulous inspection and palpation of the glottis are recommended during SML.     

Fine Needle Aspiration: A Novel Application in Laryngology

Fine needle aspiration (FNA) has had an early start in medicine and has been heavily used in the United States since the 1980s. It is regarded as a highly effective means to sample mass lesions, serving as the first diagnostic procedure in many instances. FNA is safe, less invasive than biopsy, and reduces the risk of scar formation. Its main limitations can be overcome through effective training and practiced technique. In laryngology, the development of new and diversified therapeutic and diagnostic strategies depends on the development of equally appropriate diagnostic tools. FNA has the potential to be a relatively easy procedure that can be performed under local anesthesia, increasing the otolaryngologist's armamentarium. Combining the FNA procedure with technology now available, secondary to advances in genomic science, rather than cytology and H&E stains, provides the means of obtaining clinically useful information about benign and malignant disease for clinicians and researchers. This paper provides a review of the traditional FNA procedure. It offers an introduction to the future applicability of FNA to office-based laryngology. Lastly, this paper familiarizes the reader with the genomic principles being used for this procedure.     

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.