Relationship of the cricothyroid space with vocal range in female singers

It is well documented that the cricothyroid (CT) space opens and closes with changes in pitch, narrowing with rising pitch and widening with falling pitch. Indeed, cricothyroid approximation surgery, a procedure where the CT space is deliberately made smaller, is used in male to female transgender subjects to successfully elevate vocal pitch. The present study focuses on investigating the relationship between the anterior CT space at rest and vocal range in female singers. Laryngeal dimensions (anterior CT space and heights of the thyroid and cricoid cartilages) were measured using ultrasound in 43 healthy, classically trained, female singers. Potential associations with and between age, ethnicity, anthropometric indices (height, weight, body mass index), neck dimensions (circumference and length), vocal data (practice and performance vocal range, lowest and highest practice and performance notes) along with usual speaking fundamental frequency were also explored. The main finding was that mezzo-sopranos have a significantly wider resting CT space than sopranos (11.6 mm versus 10.4 mm; P=0.007). Mezzo-sopranos also had significantly lower ‘lowest and highest’ performance notes and speaking fundamental frequencies than sopranos. Furthermore, there was a weak but significant negative correlation between the magnitude of the anterior CT space and the lowest performance note (r=-0.448; P=0.003) but there was no significant correlation with either the highest performance note or vocal range. These results suggest there is a relationship between the CT space and the lowest note a female can sing. This was evident in the correlation of a small CT space with a higher ‘lowest performance note’. It appears that the CT space influences how low female singers can sing, but not how high they can sing

The quantal larynx: The stable regions of laryngeal biomechanics and implications for speech production

Purpose: Recent proposals suggest that (a) the high dimensionality of speech motor control may be reduced via modular neuromuscular organization that takes advantage of intrinsic biomechanical regions of stability and (b) computational modeling provides a means to study whether and how such modularization works. In this study, the focus is on the larynx, a structure that is fundamental to speech production because of its role in phonation and numerous articulatory functions. Method: A 3-dimensional model of the larynx was created using the ArtiSynth platform (http://www.artisynth.org). This model was used to simulate laryngeal articulatory states, including inspiration, glottal fricative, modal prephonation, plain glottal stop, vocal–ventricular stop, and aryepiglotto– epiglottal stop and fricative. Results: Speech-relevant laryngeal biomechanics is rich with “quantal” or highly stable regions within muscle activation space. Conclusions: Quantal laryngeal biomechanics complement a modular view of speech control and have implications for the articulatory–biomechanical grounding of numerous phonetic and phonological phenomen

Hyperthyroidism in cats, part I : anatomy, physiology, pathophysiology, diagnosis and imaging

In the first part of this review article, thyroid anatomy, physiology and pathophysiology are reviewed to continue more specifically on hyperthyroidism, the most common thyroid disorder in cats. The diagnostic work-up of this disorder is discussed with emphasis on thyroid gland imaging. Scintigraphy is most commonly used and best suited to assess thyroid function, which will be discussed extensively in the second part of this review article. All other available imaging modalities do not offer a functional assessment and are therefore of limited use in the diagnosis and evaluation of hyperthyroidism

Investigating the utility of ultrasound visual biofeedback in voice instruction for two different singing styles

Smith, Kristen J. Investigating the Utility of Ultrasound Visual Biofeedback in Voice Instruction for Two Different Singing Styles. Unpublished Master of Arts thesis, University of Northern Colorado, 2021. Purpose: The purpose of this study was to investigate the potential utility of incorporating real-time visual biofeedback using ultrasonography to teach important concepts of vocal pedagogy to voice students. Exploration of innovative teaching tools, such as ultrasound visual biofeedback (U-VBF) in singing instruction, may contribute to bridging the gap between voice science and pedagogy by providing alternative ways to improve students’ kinesthetic awareness, clarify complex topics in voice physiology and acoustics, and create a common dialogue between different professionals specializing in voice. The primary research questions addressed in this study were: (a) To determine the current knowledge and attitude among voice teachers regarding use of visual biofeedback in singing instruction; (b) To determine voice teachers’ interest in learning about technology, specifically U-VBF; (c) To identify external variables that influence voice teachers’ perceptions of the usefulness and ease of use of U-VBF; and (d) To determine voice teachers’ attitudes of using U-VBF in teaching after viewing an instructional video. Methods: A pre-post survey design was adopted to assess perceptions, attitude, and interest of professional voice teachers regarding use of U-VBF before and after viewing of an instructional video on the use of ultrasound to teach concepts, such as vocal timbre, for two different singing styles: musical theater and opera. Multi-sampling methods were used to recruit professional voice teachers across the U.S. and abroad. Survey data were collected between February and April 2021. Following assumptions made by the Technology Acceptance Model (TAM) regarding user technology acceptance and behavior, data based on a final sample size of 56 participants were analyzed via descriptive statistics and thematic analysis of qualitative data. Results: Despite being largely unfamiliar with U-VBF, most participants initially expressed high expectations, believing it to be helpful in singing instruction, but difficult to use. Those who expressed more positive opinions regarding use of U-VBF in singing instruction also expressed higher levels of interest in using it in their teaching. Perceived usefulness, ease of use and interest of U-VBF were not found to be prominently related to select external variables. While perceived usefulness of U-VBF slightly declined post-viewing of the instructional video, perceived ease of use and participants’ opinions of effective use increased. Interest in the use of U-VBF as well as likelihood to use U-VBF marginally increased after viewing the video. Conclusions: These findings agree with the assumptions made by the TAM regarding associations between familiarity, perceived usefulness, perceived ease of use, and interest. Comparison between the rankings for perceived usefulness of U-VBF pre- and post-viewing of the instructional video suggests a general sense of uncertainty among voice teachers regarding use of U-VBF in singing instruction. While teachers conveyed high levels of interest, opinions of U-VBF to teach vocal pedagogy concepts slightly declined following viewing of the instructional video, suggesting a lowering of expectations. However, increased perceptions regarding ease of use indicated high levels of believed self-efficacy in using U-VBF. Understanding the relationships between perceived usefulness, ease of use, and interest can shed insight on whether voice teachers would adopt U-VBF as a supplementary tool in singing instruction

Swallowing evaluation with videofluoroscopy in the paediatric population

Paediatric swallowing disorders can have several causes, from prematurity and congenital anomalies to gastro-oesophageal reflux and infective or inflammatory pathologies of the upper digestive tract. In neonates, the swallowing process is reflexive and involuntary. Later in infancy, the oral phase comes under voluntary control, while the pharyngeal phase and oesophageal phases remain involuntary. Swallowing difficulties can severely compromise pulmonary health and nutritional intake of paediatric patients. Videofluoroscopic Swallow Study (VFSS) is a radiographic procedure that provides a dynamic view of the swallowing process and is frequently considered to be definitive evaluation for objective assessment of dysphagia in paediatric patients. This review focuses on the different possible aetiologies of paediatric swallowing disorders and related videofluoroscopic swallowing study procedures and appearances

Modeling biomechanical influence of epilaryngeal stricture on the vocal folds: A low-dimensional model of vocal-ventricular coupling

Purpose: Physiological and phonetic studies suggest that, at moderate levels of epilaryngeal stricture, the ventricular folds impinge upon the vocal folds and influence their dynamical behavior, which is thought to be responsible for constricted laryngeal sounds. In this work, the authors examine this hypothesis through biomechanical modeling. Method: The dynamical response of a low-dimensional, lumped-element model of the vocal folds under the influence of vocal-ventricular fold coupling was evaluated. The model was assessed for F0 and cover-mass phase difference. Case studies of simulations of different constricted phonation types and of glottal stop illustrate various additional aspects of model performance. Results: Simulated vocal-ventricular fold coupling lowers F0 and perturbs the mucosal wave. It also appears to reinforce irregular patterns of oscillation, and it can enhance laryngeal closure in glottal stop production. Conclusion: The effects of simulated vocal-ventricular fold coupling are consistent with sounds, such as creaky voice, harsh voice, and glottal stop, that have been observed to involve epilaryngeal stricture and apparent contact between the vocal folds and ventricular folds. This supports the view that vocal-ventricular fold coupling is important in the vibratory dynamics of such sounds and, furthermore, suggests that these sounds may intrinsically require epilaryngeal strictur

Effects of Functional Electrical Stimulation on Denervated Laryngeal Muscle in a Large Animal Model

Bilateral vocal fold paralysis (BVCP) is a life-threatening condition that follows injury to the Recurrent Laryngeal nerve (RLn) and denervation of the intrinsic laryngeal musculature. Functional electrical stimulation (FES) enables restoration and control of a wide variety of motor functions impaired by lower motor neuron lesions. Here we evaluate the effects of FES on the sole arytenoid abductor, the posterior cricoarytenoid (PCA) muscle in a large animal model of RLn injury. Ten horses were instrumented with two quadripolar intramuscular electrodes in the left PCA muscle. Following a 12-week denervation period, the PCA was stimulated using a once-daily training session for 8 weeks in seven animals. Three animals were used as unstimulated controls. Denervation produced a significant increase in rheobase (P<0.001). Electrical stimulation produced a 30% increase in fiber diameter in comparison with the unstimulated control group (33.9±2.6μm FES+, 23.6±4.2μm FES-, P=0.04). A trend toward a decrease in the proportion of type 1 (slow) fibers and an increase in type 2a (fast) fibers was also observed. Despite these changes, improvement in PCA function at rest was not observed. These data suggest that electrical stimulation using a relatively conservative set of stimulation parameters can reverse the muscle fiber atrophy produced by complete denervation while avoiding a shift to a slow (type 1) fiber type

THE EFFECTS OF THE EFFORTFUL SWALLOW MANEUVER ON HYOLARYNGEAL MOVEMENT AND TONGUE-TO-PALATE PRESSURE

Purpose: The purpose of this study was to investigate the effects of the effortful swallow maneuver under two different instructions on tongue-to-palate pressure and hyolaryngeal displacement in healthy adults. Studying typical kinematic parameters and pressure generation in healthy individuals is critical for differentiating normal from pathological patterns and for determining swallowing parameters that can be targeted to optimize and individualize treatment plans for people with swallowing disorders. The primary objectives in this study were: (1) to determine the physiological effects of two different types of effortful swallows on anterior and posterior tongue pressure generation, hyoid displacement, and hyoid-larynx approximation in healthy adults, (2) to determine age-related differences in tongue-to-palate pressure and hyolaryngeal displacement in healthy adults, and (3) to determine the association between perceived effort used to swallow and tongue pressure within swallowing conditions.Method: Forty healthy adults (20 younger, 20 older) participated in this study. All participants were in general good health, were screened for normal oral structures, function, and swallowing skills, had normal tongue strength, were eating a normal diet, and had normal auditory comprehension skills. Experimental procedures included simultaneous data acquisition of tongue pressure, submental muscle activity, and hyolaryngeal movement during normal saliva swallows and effortful saliva swallows under two different instructions (tongue emphasis and neck squeezing). Measures of tongue pressure were obtained using the Iowa Oral Performance Instrument. Submental muscle activity during swallows was assessed using surface electromyography. Hyoid excursion and hyoid-larynx approximation were obtained during ultrasonography. All outcome measures were scaled to account for differences between participants and they reflected activity during swallowing. Moreover, participants rated their perceived effort used to swallow with a visual analog scale. Results: Significant tongue pressure differences were observed between swallowing condition and tongue region. The effortful swallows performed with tongue emphasis (EFSst) and pharyngeal squeezing (EFSsp) produced greater tongue-to-plate pressures than normal swallows (NSs). Additionally, posterior tongue pressures were greater than pressures generated in the anterior tongue region during NSs and EFSst. Hyolaryngeal measures were also greater during EFSst and EFSsp than NSs. Significant differences were found between the two types of effortful swallows in tongue pressure and hyoid displacement measurements. Overall, EFSst produced greater changes in these physiological measures than EFSsp. Significant age-related differences were only found in hyoid-larynx approximation during the EFSst. Moderate correlations were identified between tongue pressure and hyoid displacement during NSs and EFSst and between tongue pressure and hyoid-larynx approximation during NSs and EFSst. Results also showed that participants perceived greater effort used to swallow during EFSst and EFSsp than NSs. Finally, there was a significant, moderate correlation between perceived swallowing effort and objectively measured tongue-to-palate pressure during NSs and EFSst. Conclusions: The effortful swallow maneuver increases tongue-to-palate pressure and hyolaryngeal excursion in healthy adults across the age span. Additionally, different instructions for the effortful swallow affect those physiological measures. These findings have the potential to guide treatment decisions when recommending and training the effortful swallow maneuver. It may be helpful for clinicians to individualize and determine the optimal effortful swallow instructions for each patient based on their physiological swallowing impairments

Computed tomographic assessment of canine arytenoid lateralization

Unilateral arytenoid lateralization is a commonly performed surgical treatment for laryngeal paralysis in dogs. It involves fixing the moveable arytenoid cartilage to the thyroid (TAL) or cricoid (CAL) cartilage or both (CTAL). This increases the area of the rima glottidis (RGA), to allow reduced airway pressure and laryngeal resistance in vitro and ameliorates clinical signs in vivo. It may also increase the patient’s predisposition for aspiration pneumonia, which occurs in around 20% of clinical patients. No surgical technique has been correlated with clinical outcome or risk of aspiration pneumonia. Objective analysis of the effects of surgery on the three dimensional structure of the larynx has not been performed. Non-invasive assessment and standardization or classification of arytenoid lateralization techniques would allow more effective prospective clinical trials to identify prognostic factors for outcome and complications. Eight cadaver larynges were secured to radiolucent materials for Computed Tomography (CT) before and after TAL, CAL and CTAL with sutures tensioned to 100g or 500g. Multiple measurements were taken from CT 3D reconstructions of the larynx to assess arytenoid displacement in three separate planes. No significant changes were found for any CT measure except the distance between the arytenoid and thyroid wing (ATW). CTAL at 500g and TAL at 500g showed significantly smaller ATW compared to CAL at 100g suggesting that a high tension TAL or CTAL causes the most lateralization of the arytenoid. CAL may allow reduction in airway pressure without excessive lateralization of the arytenoid. ATW is a candidate for a marker of lateralization of UAL procedures, which could be implemented in future prospective clinical studies. Sequential tensioning and loosening of the suture had no significant effect on any measured parameter validating the use of larynges in sequential measurements

Magnetic resonance imaging of the brain and vocal tract:Applications to the study of speech production and language learning

The human vocal system is highly plastic, allowing for the flexible expression of language, mood and intentions. However, this plasticity is not stable throughout the life span, and it is well documented that adult learners encounter greater difficulty than children in acquiring the sounds of foreign languages. Researchers have used magnetic resonance imaging (MRI) to interrogate the neural substrates of vocal imitation and learning, and the correlates of individual differences in phonetic “talent”. In parallel, a growing body of work using MR technology to directly image the vocal tract in real time during speech has offered primarily descriptive accounts of phonetic variation within and across languages. In this paper, we review the contribution of neural MRI to our understanding of vocal learning, and give an overview of vocal tract imaging and its potential to inform the field. We propose methods by which our understanding of speech production and learning could be advanced through the combined measurement of articulation and brain activity using MRI – specifically, we describe a novel paradigm, developed in our laboratory, that uses both MRI techniques to for the first time map directly between neural, articulatory and acoustic data in the investigation of vocalisation. This non-invasive, multimodal imaging method could be used to track central and peripheral correlates of spoken language learning, and speech recovery in clinical settings, as well as provide insights into potential sites for targeted neural interventions