Effects of prolonged oral reading on F0, SPL, subglottal pressure and amplitude characteristics of glottal flow waveforms

The effects of prolonged (5x45 minute) reading (vocal loading) on fundamental frequency (F0), sound pressure level (SPL), subglottal (intraroral) pressure (p), and two glottal flow waveform parameters (AC amplitude of glottal flow, f, and negative peak amplitude of differentiated flow (d) of normal female and male subjects (N = 80) were studied. Two rest (morning and noon) and three loading (two in the morning and one in the afternoon) samples were recorded and analyzed. The glottal waveforms were obtained by inverse filtering of the acoustic pressure waveforms of speaking voice samples. The analyses were based on measurement and inverse filtering of the first stressed syllable of "paappa" words repeated 3x5 times for normal, as soft as possible, and as loud as possible phonation. In normal phonation the parameter values changed statistically significantly due to loading. In many cases the values obtained in the morning samples changed after the first loading session. This is interpreted as a vocal "warming-up effect." Especially in soft phonation p, d, and f were sensitive indicators of vocal loading. In both normal and soft phonation, the SPL, p, d, and f values tended to rise due to prolonged reading in the morning and afternoon samples, indicating increased effort (normal phonation) and a rise in the phonatory threshold (soft phonation). The lunch break vocal rest ("rest effect") considerably affected the parameter values in many cases.     

Medialization Laryngoplasty With Gore-Tex: An Animal Study

Vocal cord paralysis is a disease that can cause voice disability and aspiration problems. Expanded polytetrafluoroethylene (ePTFE; Gore-Tex) has been widely used in cardiovascular and plastic surgery; however, its biocompatibility and safety have not been established precisely in the larynx. In this study, the biocompatibility and safety of ePTFE used in vocal cord medialization in the rabbit larynx were assessed. Type 1 thyroplasty with Gore-Tex was performed on one side of the larynx in eight rabbits. A sham procedure was applied on the contralateral side of their larynx. The rabbits were sacrificed after 6 months, and macroscopic and microscopic evaluations and comparisons were performed. No significant inflammatory response to Gore-Tex or displacement of the implant was seen. There was only a tiny fibrotic capsule surrounding the material in each specimen. Intense eosinophilic cell infiltration was seen surrounding one rabbit specimen. Gore-Tex seems to be a biocompatible, stable, and reversible material that can be safely used in laryngeal framework surgery.     

Vocal Fold Polyp in a Professional Brass/Wind Instrumentalist and Singer

Wind instrumentalists, especially brass players, and singers share common factors, including vocal tract shape, function and pressure, vocal fold opening and closure, breath vector of force and air flow rates. To understand the mechanism and function of the vocal folds with a pathological lesion, it is necessary to visualize the differing interactions of the vocal tract during wind and brass instrument playing and in singing. A school band director, singer, wind and brass instrumentalist, was referred by musician colleagues with intermittent dysphonia, aphonia, and inability to sing high notes. Simultaneous videolaryngoscopy, with and without stroboscopy, and external video examination were documented. An hourglass glottis with a sessile, cystic polyp of the left vocal fold were recorded and studied during phonation and the playing of 3 instruments. The techniques of glottic opening, closure, configuration and function varied with the type of instrument and phonatory function. Singing was adversely affected by the vocal fold polyp but no harmful interaction occurred during wind/brass instrument playing. Down-stream loading in singers is at the laryngeal level and in wind/brass instrumentalists is at the embouchure. Preoperative voice therapy, phonomicrosurgery, and postoperative voice rest followed by voice therapy, succeeded in restoring her combined wind/brass instrumental and singing career.     

Voice research: So What? A clearer view of voice production, 25 years of progress; the speaking voice

The past 25 years has yielded an impressive growth in our knowledge of vocal function. Interdisciplinary research cooperation in areas of laryngeal histology, vocal aerodynamics and acoustics, vocal fold vibratory characteristics, neurolaryngology, and phonatory models has led to a clearer view of voice production. This article offers a brief review of the progress that has been made in our understanding of the speaking voice and relates this knowledge to clinical practice. The importance of utilizing voice research to confirm traditional management techniques and to develop new physiologically based management approaches is also stressed.     

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.     

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.