Faculty Bibliography

OBJECTIVES/OBJECTIVE:The goals of this study were to 1) compare global protein expression in muscles of the larynx and hindlimb and 2) investigate differences in protein expression between aged and nonaged muscle using label-free global proteomic profiling methods. METHODS:Liquid chromatography-mass spectrometry (LC-MS/MS) analysis was performed on thyroarytenoid intrinsic laryngeal muscle and plantaris hindlimb muscle from 10 F344xBN F1 male rats (5 old and 5 young). Protein expression was compared and pathway enrichment analysis performed for each muscle type (larynx and limb) and age group (old and young muscle). RESULTS:Over 1,000 proteins were identified in common across both muscle types and age groups using LC-MS/MS analysis. Significant age-related differences were seen across 107 proteins in plantaris hindlimb and in 19 proteins in thyroarytenoid laryngeal muscle. Bioinformatic and enrichment analysis demonstrated protein differences between the hindlimb and larynx may relate to immune and stress redox responses and RNA repair. CONCLUSION/CONCLUSIONS:There are clear differences in protein expressions between the laryngeal and hindlimb skeletal muscles. Initial analysis suggests differences between the two muscle groups may relate to stress responses and repair mechanisms. Age-related changes in the thyroarytenoid appear to be less obvious than in the plantaris. Further in-depth study is needed to elucidate how aging affects protein expression in the laryngeal muscles. LEVEL OF EVIDENCE/METHODS:NA Laryngoscope, 2021.

Rats produce ultrasonic vocalizations (USVs) for conspecific communication. These USVs are valuable biomarkers for studying behavioral and mechanistic changes in a variety of diseases and disorders. Previous work has demonstrated operant conditioning can progressively increase the number of USVs produced by rats over multiple weeks. This operant conditioning paradigm is a useful model for investigating the effects of increased laryngeal muscle use on USV acoustic characteristics and underlying central and peripheral laryngeal sensorimotor mechanisms. Previous USV operant conditioning studies relied on manual training to elicit USV productions, which is both time and labor intensive and can introduce human variability. This manuscript introduces a semi-automated method for training rats to increase their rate of USV production by pairing commercially available operant conditioning equipment with an ultrasonic detection system. USV training requires three basic components: elicitation cue, detection of the behavior, and a reward to reinforce the desired behavior. With the semi-automated training paradigm, indirect exposure to the opposite sex or an olfactory cue can be used to elicit USV production. The elicited USV is then automatically detected by the ultrasonic acoustic system, which consequently triggers the release of a sucrose pellet reward. Our results demonstrate this semi-automated procedure produces a similar increase in USV production as the manual training method. Through automation of USV detection and reward administration, staffing requirements, human error, and subject behavioral variability may be minimized while scalability and reproducibility are increased. This automation may also result in greater experimental flexibility, allowing USV training paradigms to become more customizable for a wider array of applications. This semi-automated USV behavioral training paradigm improves upon manual training techniques by increasing the ease, speed, and quality of data collection.

Purpose The purpose of this study was to investigate the relationships among subjective auditory-perceptual ratings of vocal quality, objective acoustic and aerodynamic measures of vocal function, and patient-perceived severity of their vocal complaint. Method This study was a retrospective chart review of adult patients evaluated at a single outpatient center over a 1.5-year time period. Twenty-two clinical objective and subjective measures of voice were extracted from 676 charts (310 males, 366 females). To identify the underlying concepts addressed in an initial voice assessment, principal component analyses were conducted for males and females to account for sex differences. Linear regression models were conducted to examine the relationship between the principal components and patient perceived severity. Results Seven principal components were identified for both sexes and accounted for 75% and 71% of the variance in the clinical measures, respectively. Of these seven principal components, only two predicted male patient perceived severity, which accounted for 22% of the variance. In contrast, four principal components predicted female patient perceived severity of their voice disorder and accounted for 19% of the variance. Conclusions The results highlight the underlying aspects of vocal quality and functioning that are evaluated during an initial assessment. Male and female patients differ in which of these components may contribute self-perceived severity of a voice disorder. Identifying these underlying components may support clinical decision making when developing a clinical protocol and highlights the overlap between patient concerns and clinical measures. Supplemental Material https://doi.org/10.23641/asha.16879603.

OBJECTIVES/HYPOTHESIS/OBJECTIVE:Singers have high vocal demands and are at increased risk of developing voice disorders. Different singing genres place different technical demands on the voice. However, differences in laryngeal pathology based on genre have not been well-researched. The purpose of this study was to determine the prevalence of laryngeal pathology in different genres of professional and amateur singers who present with a voice complaint. STUDY DESIGN/METHODS:Retrospective review. METHODS:Retrospective review of patients seen at a tertiary laryngology practice. Self-identified singers who reported their primary singing genre and categorized their singing as a full-time job, part-time job, or amateur involvement were included. Type and prevalence of pathology were calculated based on genre and professional status. RESULTS:Of the 302 self-identified singers, 54% (n = 164) had laryngeal pathology. Among those with pathology, the most common finding was fibrotic lesion (38.4%, 63/164). Genres in which a majority of singers had pathology were other (69.2%, 9/13), choral (64.7%, 11/17), pop (63.2%, 12/19), musical theater (61.4%, 43/70), country (100%, 4/4), and Latin (100%, 2/2). The highest prevalence of pathology was seen in part-time professional singers (62.2%, 41/66) and full-time professionals (60.8%, 62/102), compared to amateurs (45.1%, 60/133). CONCLUSIONS:Laryngeal pathology is prevalent in singers presenting with a voice complaint. Regardless of genre or professional status, fibrotic lesions were the most common pathological finding. This study provides preliminary data on the prevalence of different laryngeal pathologies found in singers by genre and degree of professional involvement. LEVEL OF EVIDENCE/METHODS:4 Laryngoscope, 2020.

OBJECTIVE:Current clinical practice guidelines recommend a laryngoscopic referral for patients who present with hoarseness for longer than 28 days and earlier for patients with certain high-risk factors. The goal of this study was to identify additional possible concomitant health conditions in individuals with chronic (>28 days) hoarseness to improve early detection of chronic voice problems. METHODS:Using data from the 2012 National Health Interview Survey, four health conditions were selected: Swallowing problems, respiratory problems, hormonal-cycle problems, and physical activity limitations. Multivariable logistic regressions controlling for age, gender, race, and smoking status, were used to calculate the odds ratios for the association of each of these four health conditions to chronic versus acute voice problems. RESULTS:Of the 2,746 respondents who reported a voice disorder within the last year, 736 reported a voice problem lasting longer than 4 weeks in duration. After controlling for covariates, individuals reporting swallowing problems and physical activity limitations were more likely to report a chronic voice problem versus an acute voice problem, odds ratios with 95% confidence intervals of 1.983 (1.619, 2.430) and 1.716 (1.355, 2.173), respectively. No significant associations were found for respiratory or hormonal-cycle problems. CONCLUSION/CONCLUSIONS:Individuals who present with both a voice problem and a swallowing problem or physical activity limitation may be at increased risk for developing a chronic voice problem. Therefore, these two health conditions should be included as high-risk factors when determining the escalation of care for a patient presenting with acute dysphonia.

OBJECTIVE/UNASSIGNED:Oversimplified clinical dogma suggests that laryngeal diseases fall into two broad, mutually exclusive diagnostic categories-mucosal injury or neuromuscular/functional disorders. Extensive investigation in the lower airway as well as other organ systems suggest complex interactions between tissue types underlying both tissue health and pathological states. To date, no such relationship has been described in the vocal folds, likely the most bioactive organ in the body. We hypothesize interactions between the vocal fold muscle and mucosa likely contribute to aberrant phonatory physiology and warrant further investigation to ultimately develop novel therapeutic strategies. METHODS/UNASSIGNED:Primary culture of myoblasts from rat thyroarytenoid muscle and fibroblasts from the vocal fold mucosa were established. Co-culture and conditioned media experiments were performed to established bidirectional interactions between cell types. Transforming Growth Factor (TGF)-β was employed to stimulate a fibrotic phenotype in culture. In addition to quantitative PCR, standard migration and proliferation assays were performed as well as immunocytochemistry. RESULTS/UNASSIGNED:Bidirectional cell-cell interactions were observed. Without TGF-β stimulation, myoblast conditioned media inhibited fibroblast migration, but enhanced proliferation. Conversely, fibroblast conditioned media increased both myoblast proliferation and migration. Myoblast conditioned media decreased TGF-β-mediated gene expression and of particular interest, ACTA2 mRNA expression. In both co-culture and in response to fibroblast conditioned media, myosin heavy chain (Myh2) mRNA expression decreased in myoblasts. CONCLUSIONS/UNASSIGNED:These data are the first to describe interactions between cell types within the vocal fold. The implications for these interactions in vivo warrant further investigation to develop and refine optimal treatment strategies.

The application of exercise science training knowledge has been of growing interest to voice professionals. This tutorial, derived from the authors' invited presentations from the "Exercise and the Voice" Special Session at the 2018 Voice Foundation Symposium, proposes a foundational theoretical structure based in exercise science, clarifies the wide range of variables that may influence voice training, and summarizes our present understanding of voice physiology from the perspective of muscle training. The body of literature on voice exercise was then analyzed from the perspective of this framework, identifying what we currently know and what we still have yet to learn.

OBJECTIVES/HYPOTHESIS/OBJECTIVE:Menopause adversely affecs power and endurance of the limb muscles. However, despite clinical observations that menopause corresponds to negative changes of the voice, the direct effects of estrogen deprivation on the thyroarytenoid muscles are unknown. The purpose of this study was to investigate the effects of estrogen deprivation via ovariectomy on three neuromuscular parameters of the thyroarytenoid muscles using a rat model. STUDY DESIGN/METHODS:Animal model. METHODS:Cryosections of vocal folds of 20 (10 control and 10 ovariectomized) female rats were stained to label neuromuscular junctions, fiber size, or parvalbumin levels using immunohistochemical techniques and compared between experimental groups. RESULTS:The neuromuscular junctions, thyroarytenoid fiber sizes, and parvalbumin levels of the vocal folds were similar between experimental groups. CONCLUSIONS:The loss of estrogen did not change neuromuscular parameters of the vocal folds of adult female rats; therefore, vocal changes within the outer vibratory layers of the vocal folds may primarily be responsible for clinically observed menopausal vocal changes. LEVEL OF EVIDENCE/METHODS:NA Laryngoscope, 2020.