The Evolving Etiology of Bilateral Vocal Fold Immobility

In the past, bilateral vocal fold immobility (BVFI) occurred most commonly after thyroidectomy. However, no large series documenting the etiology of adult BVFI has been published within the past fifteen years. This study reviews the etiologic patterns of BVFI at our institutions. We compare BVFI from before and after 1980. We also review combined studies of unilateral vocal fold immobility (UVFI) to compare and unilateral versus bilateral etiologic trends. In comparison with previously published series, fewer cases of BVFI present today as a complication of thyroid surgery and more as the result of malignancies and nonsurgical trauma. Unfortunately, BVFI caused by malignancy is not usually an initial sign of local disease, but an ominous sign of recurrence or metastases. In comparing UVFI and BVFI we found that thyroidectomy causes a higher percentage of BVFI than of UVFI. Over one-third of UVFI cases were caused by neoplasm which further underscores the potential seriousness of immobile vocal folds and the need for careful investigation.     

The Voice and Its Care: Survey Findings From Actors'' Perspectives

There is a need for research that would determine how the speech-language-voice pathologist could best be of service to actors who are experiencing vocal dysfunction or in furnishing preventive educational information. A questionnaire investigating interest and knowledge levels of vocal function and dysfunction was distributed to 543 subjects from the Pacific Northwest and British Columbia. A total of 345 questionnaires, including those completed by 79 professional actors, 73 amateur actors, 124 acting students, and 69 controls, were analyzed. Professional actors and amateur actors indicated the highest levels of interest in gaining further knowledge regarding the role of the speech-language pathologist (SLP) and the voice and vocal hygiene. Professional actors and amateur actors also reported higher perceived knowledge levels than the other groups in these areas, although very few claimed to have a thorough knowledge in the areas under investigation. Professional actors answered more knowledge-based questions correctly than amateur actors, acting students, and controls in the areas regarding the role of the SLP and voice and vocal hygiene. However, the professional actors' scores were not significantly higher than amateur actors in either area and were only significantly higher than acting students on the vocal hygiene items. Implications for a preventive approach to vocal health are discussed.     

Vocal Process Avulsion

Vocal process avulsion is a rare complication of intubation or external laryngeal trauma that can cause significant dysphonia. The vocal process develops independently from the body of the arytenoid cartilage, which results in a fusion plane that is vulnerable to trauma. The findings of vocal process avulsion may be subtle, and the relationship of the vocal process to the body of the arytenoid cartilage must be examined closely. Stroboscopy is critical in the evaluation. We describe three cases of vocal process avulsion encountered by the senior author (R.T.S.) over the last 5 years and discuss our approaches to evaluation and treatment. All cases were repaired endoscopically. However, we used three different techniques. These include chemical tenotomy with botulinum toxin, closed reduction with fat injection, and open reduction via cordotomy.     

On Ample Line Bundles Which Are not Spanned on Abelian 3–Folds

Let (X, L) be a polarized abelian 3 – fold over the complex number field. In this paper, we classify (X, L) such that |L| has a base point with L³ ≥ 30.     

A reduced-order flow model for vocal fold vibration: From idealized to subject-specific models

We present a reduced-order model for fluid–structure interaction (FSI) simulation of vocal fold vibration during phonation. This model couples the three-dimensional (3D) tissue mechanics and a one-dimensional (1D) flow model that is derived from the momentum and mass conservation equations for the glottal airflow. The effects of glottal entrance and pressure loss in the glottis are incorporated in the flow model. We consider both idealized vocal fold geometries and subject-specific anatomical geometries segmented from the MRI images of rabbits. For the idealized vocal fold geometries, we compare the simulation results from the 1D/3D hybrid FSI model with those from the full 3D FSI simulation based on an immersed-boundary method. For the subject-specific geometries, we incorporate previously estimated tissue properties for individual samples and compare the results with those from the high-speed imaging experiment of in vivo phonation. In both setups, the comparison shows good agreement in the vibration frequency, amplitude, phase delay, and deformation pattern of the vocal fold, which suggests potential application of the present approach for future patient-specific modeling.     

The Progress of Ageing of Lignin-containing Paper Induced by Light and its Relation to Chemiluminescence – Temperature Runs

Lignin-containing papers from different sources and of different age were irradiated by the visible light and the progress of the degradation reaction was followed by non-isothermal chemiluminescence method. Kinetic data obtained for papers degraded in oxygen were compared with double fold endurance test and carbonyl groups concentration. The effect of lignin on degradation of cellulose after deacidification treatment of the paper by methoxymagnesium methylcarbonate (MMMC) was ascertained and a mechanism of co-oxidation of lignin and cellulose in originally alkaline conditions was outlined.     

Rhabdomyoma of the true vocal fold

Rhabdomyomas of the larynx are exceedingly rare. The incidence, sites of occurrence in the larynx, and treatment of these benign striated muscle tumors are reviewed. A case of rhabdomyoma involving the vocalis muscle is presented with magnetic resonance imaging and video-stroboscopic documentation.     

Effects of simulated source of tremor on acoustic and airflow voice measures

To test the effects of different sources of tremor on the voice, tremor was simulated by external rhythmic perturbation of structures at the subglottal, glottal, and supraglottal levels in 10 healthy subjects. The acoustic and airflow signals simultaneously recorded during sustained phonation in the normal and the 3 simulated tremor conditions were analyzed and compared. Voice measures included: fundamental frequency, 2 short-term perturbation measures (jitter and shimmer), and 3 long-term tremor measures (prominence ratios of the spectral peaks of the acoustic frequency contour, acoustic amplitude contour, and airflow contour). Measures of fundamental frequency and percent shimmer were not significantly affected by the simulated tremors. Measures of percent jitter and the amplitudes of the long-term frequency and amplitude modulations were most prominently increased when respiratory drive was perturbed by simulated tremor. Spectral analysis of the acoustic amplitude contour was most useful in distinguishing the 3 sites of simulated tremor.     

The interrelationship of subglottic air pressure, fundamental frequency, and vocal intensity during speech

In this study we have simultaneously measured subglottic air pressure, airflow, and vocal intensity during speech in nine healthy subjects. Subglottic air pressure was measured directly by puncture of the cricothyroid membrane. The results show that the interaction between these aerodynamic properties is much more complex that previously believed. Certain trends were seen in most individuals, such as an increase in vocal intensity with increased subglottic air pressure. However, there was considerable variability in the overall aerodynamic properties between subjects and at different frequency and intensity ranges. At certain frequencies several subjects were able to generate significantly louder voices without a comparable increase in subglottic air pressure. We hypothesize that these increases in vocal efficiency are due to changes in vocal fold vibration properties. The relationship between fundamental frequency and subglottic pressure was also noted to vary depending on vocal intensity. Possible mechanisms for these behaviors are discussed.