The role of sensory dysfunction in the development of voice disorders, chronic cough and paradoxical vocal fold movement

Mechanotransduction in the Vocal Fold Microenvironment: A Narrative Review

PURPOSE

The vocal fold tissues undergo nearly continuous and repeated cycles of injury and repair throughout the course of an individual's lifetime. It is well established that certain individuals are at greater risk of lesion development based on personality and behavioral classification. However, these characteristics alone do not wholly predict or explain lesion development or severity. In this review, we discuss current knowledge of mechanotransduction proteins and their potential relevance to tissue homeostasis in the vocal folds.

METHOD

A review of literature surrounding mechanotransduction and tissue homeostasis as it relates to the vocal folds was conducted. Review of the literature included searches of PubMed, Google Scholar, and other various online peer-reviewed sources. Search terms pertained to mechanosensation, mechanotransduction, mechanically activated channels, mechanical cellular regulation, and other associated concepts and terms. Additional literature was identified through the reference lists of identified papers. Findings of this literature review were then applied to known physiology and pathophysiology of the vocal folds in order to speculate on the contribution of mechanically mediated mechanisms within the vocal fold.

DISCUSSION AND CONCLUSION

Because the vocal folds are such mechanically active structures, withstanding nearly constant external forces, there is strong support for the idea that mechanically sensitive molecular pathways within the vocal fold tissue play a major role in tissue homeostasis in the presence of these considerable forces. As such, mechanotransduction within the vocal fold should be considered and targeted in future biological studies of vocal fold physiology.

Practical multidisciplinary framework for the assessment and management of patients with unexplained chronic aerodigestive symptoms

OBJECTIVE

Patients experiencing unexplained chronic throat symptoms (UCTS) are frequently referred to gastroenterology and otolaryngology outpatient departments for investigation. Often despite extensive investigations, an identifiable structural abnormality to account for the symptoms is not found. The objective of this article is to provide a concise appraisal of the evidence-base for current approaches to the assessment and management of UCTS, their clinical outcomes, and related healthcare utilisation.

DESIGN

This multidisciplinary review critically examines the current understanding of aetiological theories and pathophysiological drivers in UCTS and summarises the evidence base underpinning various diagnostic and management approaches.

RESULTS

The evidence gathered from the review suggests that single-specialty approaches to UCTS inadequately capture the substantial heterogeneity and pervasive overlaps among clinical features and biopsychosocial factors and suggests a more unified approach is needed.

CONCLUSION

Drawing on contemporary insights from the gastrointestinal literature for disorders of gut-brain interaction, this article proposes a refreshed interdisciplinary approach characterised by a positive diagnosis framework and patient-centred therapeutic model. The overarching aim of this approach is to improve patient outcomes and foster collaborative research efforts.

Relationships Between Laryngoscopic Analysis Metrics of Supraglottic Compression and Vocal Effort in Primary Muscle Tension Dysphonia

PURPOSE

Supraglottic compression is thought to underlie vocal effort in patients with primary muscle tension dysphonia (pMTD). However, the relationship between supraglottic compression and vocal effort in this clinical population remains unclear. Gold standard laryngoscopic assessment metrics for supraglottic compression are also lacking. The goals of this study were to identify metrics proposed in the literature that could distinguish patients diagnosed with pMTD from typical voice users and determine their relationships to the vocal effort.

METHODS

Flexible laryngeal endoscopy was performed on 50 participants (25 pMTD, 25 controls). The presence of supraglottic compression was characterized using a categorical (nominal) scale and severity was quantified on ordinal and continuous scales. The three laryngoscopic metrics were correlated with self-perceived ratings of vocal effort on a 100 mm visual analog scale.

RESULTS

Inter-rater reliability was strongest for the continuous scale (P's < 0.0001) compared to categorical (P's < 0.001) and ordinal (P's < 0.001) scales. The presence of different supraglottic compression patterns varied in both groups, and there were no significant group differences on categorical (P's > 0.05) scales. Mediolateral (M-L) supraglottic compression was significantly greater in the pMTD group (P < 0.0001), and anteroposterior (A-P) compression was significantly greater in the control group (P = 0.001) using continuous scales. There were no significant relationships between any of the three laryngoscopic metric types and vocal effort ratings (P's > 0.05), except for a significantly positive relationship between anterior-posterior compression on the ordinal scale and vocal effort in the control group (P = 0.047).

CONCLUSIONS

Continuous scales are reliable and valid for distinguishing individuals with pMTD from those without voice disorders, especially occupational voice users. M-L supraglottic compression may be a better indicator of pMTD than A-P compression. However, the poor correlation between supraglottic compression and vocal effort suggests that one may not influence the other. Future studies should focus on other mechanisms underlying vocal effort in patients with pMTD.

Interoception, Voice Symptom Reporting, and Voice Disorders

OBJECTIVES

Interoception may play a role in how individuals perceive their voice disorder. The first objective of this study was to investigate relationships between interoception and voice disorder class (functional, structural, neurological). The second objective was to determine relationships between interoception and voice-related outcome measures between patients with functional voice and upper airway disorders and typical voice users. The third objective was to determine whether patients with primary muscle tension dysphonia (a type of functional voice disorder) had different levels of interoceptive awareness than typical voice users.

STUDY DESIGN

Prospective cohort study.

METHODS

One hundred subjects with voice disorders completed the multidimensional assessment of interoceptive awareness-2 (MAIA-2). Voice diagnosis and singing experience were also acquired from each patient's medical chart. Voice handicap (VHI-10) and Part 1 of the vocal fatigue index (VFI-Part1) scores were obtained from patients diagnosed with functional voice and upper airway disorders. MAIA-2, VHI-10, VFI-Part1, and singing experience were also obtained from 25 typical voice users. Multivariable linear regression models were used to assess the association between response variables and voice disorder class, adjusting for singing experience, gender, and age.

RESULTS

There were no significant group differences between voice disorder class (functional, structural, neurological) after adjusting for multiple comparisons. Participants with functional voice and upper airway disorders who scored significantly higher on the VHI-10 and VFI-Part1 had lower Attention Regulation sub-scores on the MAIA-2 (P's<0.05). Patients with primary muscle tension dysphonia scored significantly lower on the Emotional Awareness MAIA-2 subscale than typical voice users (P=0.005).

CONCLUSION

Patients with functional voice disorders with lower capabilities to attend to body sensations may score higher on voice-related patient-reported outcome measures, like the VHI-10 and VFI-Part1. Patients with primary muscle tension dysphonia may also have lower capabilities in processing their body sensations than typical voice users.

Is there Really a Lump in My Throat? The Incidence and Implication of Vocal fold Abnormalities in Patients Presenting with Globus

OBJECTIVE

To identify the prevalence of vocal fold abnormalities in patients with a primary complaint of globus sensation. Secondly, to determine the relationship between globus, vocal fold abnormality, and patient-reported quality of life questionnaire score.

STUDY DESIGN

Retrospective chart review.

METHODS

A retrospective chart review was performed to identify all new patients evaluated at a tertiary academic care laryngology practice between January 2018 and December 2018 presenting with a chief complaint of globus. Variables of interest include age, gender, laryngeal symptoms, self-reported quality-of-life questionnaire results, and laryngostroboscopy findings. Questionnaires selected for this investigation include the reflux symptom index (RSI), eating assessment tool-10 (EAT-10), and voice handicap index-10 (VHI-10).

RESULTS

Two hundred twenty-eight subjects with an average age of 54 ±17 years, were categorized based on one of three laryngostroboscopic findings: absence of vocal fold abnormality, vocal fold paresis/paralysis (motion abnormality), or a vocal fold mass lesion. Fifty percent of patients reporting globus had a normal laryngeal exam, and 50% had a mass lesion or motion abnormality. Twenty five percent had vocal fold motion abnormality (paresis, paralysis, or supraglottic squeeze); 19% had a mass lesion; and 3% had both a lesion and motion abnormality. The average self-reported survey scores were compared among the three groups. Patients with dysphonia had a significantly higher VHI-10 (P = 0.00), and a significantly higher RSI (P =  0.00) than those without dysphonia. Those patients with dysphagia had significantly higher EAT-10 (P = 0.00) and RSI (P = 0.02) scores than those who did not have dysphagia. Patients with vocal fold motion abnormality had significantly higher VHI-10 than those with normal vocal fold mobility (P = 0.02) CONCLUSIONS: Identifying the etiology of globus presents a significant challenge to laryngologists. Data presented here suggest that vocal fold abnormalities may contribute to the sensation of globus and should therefore be considered in the differential when managing these patients.

Integrative Review and Framework of Suggested Mechanisms in Primary Muscle Tension Dysphonia

PURPOSE

Despite the high prevalence of primary muscle tension dysphonia (MTD-1), its underlying mechanisms and their interrelationships have yet to be fully identified. The objectives of this integrative review were (a) to describe and classify the suggested underlying mechanisms for MTD-1, (b) to appraise the empirical evidence supporting each of the proposed mechanisms, and (c) to summarize the information in an integrative model.

METHOD

PubMed, Scopus, and CINAHL were searched for all publications pertaining to muscle tension dysphonia. Papers were retained if they included theoretical or empirical data pertaining to underlying mechanisms of MTD-1. A total of 921 papers initially qualified for screening, of which 100 remained for consideration in this review. Underlying mechanisms of MTD-1 were extracted using a consensus approach.

RESULTS

Seven broad categories of putative mechanisms involved in MTD-1 were identified: psychosocial, autonomic, sensorimotor, respiratory, postural, inflammatory, and neuromuscular. These categories were further divided into 19 subcategories detailed in the body of this review article. Based on the reviewed evidence, our proposed integrative model presents MTD-1 as an idiosyncratic motor adaptation to physiological perturbation or perceived threat. Under this model, physiologically or psychologically aversive stimuli can instigate a series of motor adaptations at multiple levels of the nervous system, ultimately disturbing muscle activation patterns and their biomechanical outcomes. Importantly, these adaptations appear to have the potential to become chronic even after threatening stimuli are withdrawn.

CONCLUSIONS

The proposed model highlights the importance of personalized rehabilitation in MTD-1 treatment. Limitations of the literature are discussed to provide guidance for future research aimed at improving our understanding of MTD-1.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.19586065.

Irritant-Induced Chronic Cough Triggers: A Scoping Review and Clinical Checklist

Purpose The primary aim of this review was to identify environmental irritants known to trigger chronic cough through the life span and develop a comprehensive clinically useful irritant checklist. Method A scoping review was conducted using the Preferred Reporting Items for Systematic Review and Meta-Analysis Extension for Scoping Reviews, checklist, and explanation. English-language, full-text resources were identified through Medline, PsycINFO, SPORTDiscus, Web of Science, and ProQuest Dissertations and Theses Global. Results A total of 1,072 sources were retrieved; of these, 109 were duplicates. Titles of abstracts of 963 articles were screened, with 295 selected for full-text review. Using the exclusion and inclusion criteria listed, 236 articles were considered eligible and 214 different triggers were identified. Triggers were identified from North America, Europe, Africa, Asia, and Australia. Occupational exposures were also delineated. Conclusions A clinically useful checklist of both frequently encountered triggers and idiosyncratic or rare triggers was developed. The clinical checklist provides a unique contribution to streamline and standardize clinical assessment of irritant-induced chronic cough. The international scope of this review extends the usefulness of the clinical checklist to clinicians on most continents.

Voice-related complaints and vocal and nonvocal habits of Hindustani classical singers: a questionnaire-based study

OBJECTIVE

This study aimed to profile voice-related complaints, as well as vocal and nonvocal habits among Hindustani classical singers.

METHOD

Cross-sectional study design was used to profile voice-related complaints and vocal and nonvocal habits among Hindustani classical singers. Phase I involved developing a questionnaire for exploring vocal and nonvocal habits. Phase II involved the administration of the survey to 61 Hindustani classical singers.

RESULTS

Based on the overall findings, 41% of singers reported of at least three vocal symptoms. The most common vocal symptoms included out of breath while singing, felling tired after singing and experiencing tension or tightness in neck/shoulder. The commonly reported vocal habits included excessive phone use, loud coughing/sneezing, throat clearing and excessive speaking. A high consumption of caffeinated beverages and spicy food were also reported.

CONCLUSION

This study helps to highlight the voice-related complaints and vocal and nonvocal habits of Hindustani classical singers. Further studies, need to explore the prevalence of voice problems incorporating other dimensions of voice evaluation such as acoustic, auditory perceptual, self-reported and laryngeal examination.

Drug-Induced Paradoxical Vocal Fold Motion

Vocal cord dysfunction, also known as paradoxical vocal fold motion (PVFM), is a disorder characterized by abnormal vocal cord adduction during inspiration. PVFM is commonly misdiagnosed as asthma because of the similarity of symptoms: cough, wheezing, chest pain, and dyspnea. We present the clinical vignette of a 36-year-old woman with juvenile rheumatoid arthritis and multiple adverse drug reactions who presented with recurrent episodes of unrecognized PVFM during skin testing for drug allergy, omalizumab treatment, and tocilizumab desensitization. Before the diagnosis of PVFM, these episodes were treated as anaphylaxis, including the administration of epinephrine. Once diagnosed and treated for PVFM, the patient did not present any further events and continued treatment for drug allergy. PVFM may be underreported in hypersensitivity reactions because of the similarity to Type 1-mediated respiratory symptoms and comorbid asthma.

Acute Management of Paradoxical Vocal Fold Motion (Vocal Cord Dysfunction)

Paradoxical vocal fold motion disorder, also commonly termed vocal cord dysfunction, is a poorly understood cause of acute upper airway obstruction. Patients with paradoxical vocal fold motion frequently present to the emergency department (ED) with acute respiratory distress and stridor. Lack of familiarity with this disorder may lead to delayed diagnosis or misdiagnosis and unnecessary intubations or surgical airway procedures. Although long-term management of paradoxical vocal fold motion is well described, there is a paucity of information about acute evaluation and management. This article aims to summarize the ED presentation and management of paradoxical vocal fold motion.

The Ability of Patient-Symptom Questionnaires to Differentiate PVFMD From Asthma

OBJECTIVES

Goals of the current study were to (1) conduct initial validation of a new Paradoxical Vocal Fold Movement Disorder Screening Questionnaire (PVFMD-SQ); (2) determine if symptom-based questionnaires can discriminate between patients with confirmed PVFMD and those with diagnosed uncontrolled asthma without clinical suspicion for PVFMD; and (3) determine if a new questionnaire with diagnostic specificity could be created from a combination of significant items on previously validated questionnaires.

METHODS

This is a prospective, case-controlled study of patients with PVFMD only and asthma only, who completed five questionnaires: Dyspnea Index, Reflux Symptom Index, Voice Handicap Index-10, Sino-Nasal Questionnaire, and PVFMD-SQ. Factor analysis was completed on the new PVFMD-SQ, and the discrimination ability of selected factors was assessed by receiver operating characteristics curve. The factor with the greatest discriminatory ability was selected to create one diagnostic questionnaire, and scores for each participant were calculated to estimate how well the factor correlated with a PVFMD or asthma diagnosis. Mean scores on all questionnaires were compared to test their discriminatory ability.

RESULTS

Patients with PVFMD showed greater voice handicap and reflux symptoms than patients with asthma. A 15-item one-factor questionnaire was developed from the original PVFMD-SQ, with a sensitivity of 89% and specificity of 73% for diagnosing asthma versus PVFMD. The combined questionnaires resulted in four factors, none of which showed discriminatory ability between PVFMD and asthma.

CONCLUSION

This study represents the first time that a patient symptom-based screening tool has shown diagnostic sensitivity to differentiate PVFMD from asthma in a cohort of symptomatic patients.

Vocal cord dysfunction diagnosis may be improved by a screening check list

BACKGROUND

Many patients with vocal cord dysfunction (VCD), with or without asthma, receive inappropriate treatment because they are misdiagnosed as having difficult-to-control asthma alone. We developed a clinical screening check list designed to aid the diagnosis of VCD.

METHODS

A prospective observational study involving 80 patients aged ≥18 years, diagnosed with severe asthma. After anamnesis and physical examination, physicians completed a check list with 6 questions to identify VCD, for which the answer "yes" counted one point. Then patients underwent spirometry and laryngoscopy. On the basis of the laryngoscopic findings, we created three patient groups: VCD (vocal cord adduction during inspiration, n = 14); unconfirmed VCD (inconclusive findings, n = 29); and control (normal findings, n = 37). We attempted to determine whether any of those groups were associated with the responses to individual questions or sets of questions on the check list.

RESULTS

The proportion of affirmative answers to the question "Does pulmonary auscultation reveal wheezing, predominantly in the cervical region, and/or stridor?" was significantly higher for the VCD group than for the other two groups (P = 0.006), notably in elderly patients. The variable "4 or more affirmative answers" was more common in VCD and unconfirmed VCD groups in comparison to controls (P = 0.022).

CONCLUSIONS

A finding of wheezing or stridor on auscultation of the cervical region is suggestive of vocal cord dysfunction, especially in elderly patients, and such dysfunction can be confirmed through laryngoscopy. Our VCD screening check list proved to be useful in the screening of VCD among patients with severe asthma.

The Relationship Between Voice and Breathing in the Assessment and Treatment of Voice Disorders

Coordination between the larynx and lower airways is essential for normal voice production. Dyscoordination may contribute to myriad voice problems. The current study provides an overview of respiratory and laryngeal physiology as it relates to normal and disordered voice production, as well as a review of phonatory aerodynamic assessment practices. Finally, the integration of voice and breathing in common voice therapy programs is explored.

Airway Hypersensitivity, Reflux, and Phonation Contribute to Chronic Cough

BACKGROUND & AIMS

Although chronic cough is common, its etiology is often elusive, making patient management a challenge. Gastroesophageal reflux and airway hypersensitivity can cause chronic cough. We explored the relationship between reflux, phonation, and cough in patients with idiopathic chronic cough.

METHODS

We performed a blinded, cross-sectional study of nonsmoking patients with chronic cough (duration, >8 weeks) refractory to reflux treatment referred to the Digestive Disease Center at Vanderbilt University. All underwent 24-hour acoustic recording concurrently and temporally synchronized with ambulatory pH-impedance monitoring. Cough, phonation, and pH-impedance events were recorded. We evaluated the temporal relationship between cough and phonation or reflux events using Poisson and logistic regression.

RESULTS

Seventeen patients met the inclusion criteria (88% female; 100% white; median age, 63 years [interquartile age range, 52-66 years]; mean body mass index, 30.6 [interquartile range, 27.9-34.0]); there were 2048 analyzable coughing events. The probability of subsequent coughing increased with higher burdens of preceding cough, reflux, or phonation. Within the first 15 minutes after a cough event, the cough event itself was the main trigger of subsequent cough events. After this period, de novo coughing occurred with increases of 1.46-fold in association with reflux alone (95% confidence interval, 1.17-1.82; P < .001) and 1.71-fold in association with the combination of phonation and reflux events.

CONCLUSIONS

Antecedent phonation and reflux increased the rate of cough events in patients with idiopathic chronic cough. Reflux events were more strongly associated with increased rate of coughing. Our findings support the concept that airway hypersensitivity is a cause of chronic cough, and that the vocal folds may be an effector in chronic cough ClinicalTrials.gov number: NCT01263626.

Comparative analysis of clinical profile: Chronic cough vs paradoxical vocal fold motion

BACKGROUND

Ongoing contention surrounding typical demographic and clinical attributes of chronic cough (CC) and paradoxical vocal fold motion (PVFM) impedes timely diagnosis and optimum patient care. Designed to reduce preventable patient morbidity through improved recognition and differentiation, the current study aimed to determine representative clinical profiles for CC and PVFM, with identification of distinctive attributes from the general population and risk factors associated with each diagnosis.

METHODS

Self-reported medical questionnaires, demographic and lifestyle attributes of CC and PVFM cases from a disease-specific outcomes database were compared to US population data and published normative values. Univariate comparison and multivariate regression modelling of age, sex, alcohol intake, smoking, Reflux Symptom Index (RSI), Voice Handicap Index (VHI), and Generalized Anxiety Disorder 7-item Scale (GAD-7) determined distinguishing features between the clinical groups, including odds ratios for presenting with CC versus PVFM.

RESULTS

Clinical profiles developed from 283 (128 CC, 155 PVFM) adults (18-91 years) were significantly different from the general population across each demographic, lifestyle and clinical variable (all p < .01), with the exception of obesity. Age (55.39 ± 13.54 vs 45.07 ± 16.51 years, p < .01) and mean RSI score (21.5 ± 9.02 vs 18.1 ± 9.08, p < .01) most reliably distinguished CC from PVFM, with those aged 60-69 years (OR = 9.45) most likely to be diagnosed with CC.

CONCLUSIONS

Standard clinical profiles of CC and PVFM are distinct from the general population, aiding determination of relative probabilities and risk factors in the differential diagnostic process. Variations between CC and PVFM were subtle, reliably distinguished by age and relative severity of laryngopharyngeal reflux symptomatology.

Vocal cord dysfunction and asthma

PURPOSE OF REVIEW

Vocal cord dysfunction can occur independently or can co-exist with asthma. It often mimics asthma in presentation and can be challenging to diagnose, particularly in those with known asthma. Vocal cord dysfunction remains under-recognized, which may result in unnecessary adjustments to asthma medicines and increased patient morbidity. There is a need to review current literature to explore current theories regarding disease presentation, diagnosis, and treatment.

RECENT FINDINGS

The underlying cause of vocal cord dysfunction is likely multifactorial but there has been increased interest in hyper-responsiveness of the larynx. Many intrinsic and extrinsic triggers have been identified which in part may explain asthma-like symptomatology. A variety of techniques have been reported to provoke vocal cord dysfunction during testing which may improve diagnosis. There is a significant gap in the literature regarding specific laryngeal control techniques, duration of therapy, and the effectiveness of laryngeal control as a treatment modality.

SUMMARY

Those with vocal cord dysfunction and asthma report more symptoms on standardized asthma control questionnaires, which can result in increasing amounts of medication if vocal cord dysfunction is not identified and managed appropriately. Clinicians need to maintain a high index of suspicion to identify these patients. Videolaryngostroboscopy remains the diagnostic method of choice. Evidence-based guidelines are needed for the most effective diagnostic techniques. Laryngeal control taught by speech pathologists is the most common treatment. Effectiveness is supported in case reports and clinical experience, but not in larger randomized trials which are needed.

Current knowledge, controversies and future directions in hyperfunctional voice disorders

Taking the preceding five papers in this special issue of the International Journal of Speech-Language Pathology as a starting point, this paper synthesizes key aspects of hyperfunctional voice disorders (HFVD). Aetiological and contributing factors, defining features, prevention, assessment and intervention are canvassed, while controversial issues and future directions in research and clinical practice are discussed. Despite disagreements and inconsistencies in terminology surrounding HFVD, there is broad agreement that musculoskeletal tension is the hallmark of these voice disorders. There is also reasonable consensus that the pathogenesis and persistence of HFVD are associated with multiple and overlapping factors, some of which are likely to interact in as yet unknown ways. In addition to dysregulated laryngeal muscle functioning, key processes in the psychosocial and sensory domains are canvassed as likely contributors to HFVD. Vocal fatigue is considered as an intriguing relative of HFVD, the role of laryngopharyngeal reflux is debated and the proposition that particular individuals are psychologically and/or physiologically predisposed to HFVD is discussed. New directions in assessment highlight the use of client-centred measures to consider insider perspectives of psychological factors, vocal effort and vocal fatigue. Emerging psychosocial and physical-manipulative interventions are emphasized and the future educational needs of voice care professionals are considered.