Examining the Influence of Chemosensation on Laryngeal Health and Disorders

Optimizing the Diagnosis and Management of Pediatric Inducible Laryngeal Obstruction

BACKGROUND

Pediatric inducible laryngeal obstruction (ILO) is difficult to diagnose and treat. Patients often undergo multiple specialist referrals, and long-term outcomes are not well reported.

OBJECTIVES

To investigate the patterns of presentation, workup, and management of children who were diagnosed with ILO at the Stollery Children's Hospital.

METHODS

Retrospective review with a prospective cohort of pediatric patients diagnosed with ILO from 2015 to 2023. We collected the demographic data, diagnostic tests, specialist referrals, time to diagnosis, symptom burden, associated comorbidities and aggravating factors, management, and treatment outcomes. A subset of patients was followed prospectively to determine treatment outcomes. A basic descriptive analysis was performed, and factors associated with time to resolution were studied.

RESULTS

Seventy-eight patients met the criteria for inclusion, with 22 completing prospective questionnaires. The average age was 14 years old, and 75% were female. The majority required multiple specialist referrals. The majority were associated with exercise. Thirty-two (41%) patients had a presumed diagnosis of asthma, despite only four pulmonary function tests being consistent with asthma. Abortive breathing exercises were the most commonly employed (95%) and most successful (61%) nonsurgical management technique. Surgery was highly successful in a small cohort of patients. Median time to symptom resolution was 12 months, with 36% reporting symptoms persistent beyond 3 years.

CONCLUSIONS

Pediatric ILO often goes undiagnosed for prolonged periods. Exercise-related symptoms are the most common. Management strategies have varied levels of success and a large proportion of patients have prolonged symptoms despite treatment, as supported by other recent evidence.

LEVEL OF EVIDENCE

3 Laryngoscope, 135:1207-1211, 2025.

Current opinion in refractory and/or unexplained chronic cough

PURPOSE OF REVIEW

Otolaryngologists are vital to successfully managing chronic cough in adults. This review presents updates regarding rapidly evolving concepts in chronic cough.

RECENT FINDINGS

Significant growth is occurring in chronic cough research, strengthening the evidence of its major psychosocial impacts. Elucidation of the neural underpinnings of normal and abnormal cough within both the peripheral and central nervous systems highlight the previously underappreciated complexity of cough. Recent clinical practice recommendations emphasize personalized treatment approaches through addressing treatable traits of chronic cough. Investigations are ongoing to better distinguish chronic cough subgroups, and multiple types of important clinical outcome measures are being characterized. Newer research about chronic cough treatment encompasses pharmacologic and nonpharmacologic interventions, including oral and inhaled medications, superior laryngeal nerve blocks, and behavioral therapy.

SUMMARY

As knowledge about chronic cough in adults continues to expand in both research and clinical practice, otolaryngologists can continue to raise awareness of the role of the larynx in cough and promote ongoing multidisciplinary collaborations. In the coming years, more pharmacologic options and personalized treatment approaches will likely emerge for chronic cough.

Competitive Swim Breathing: A Survey-Informed Tutorial for Speech-Language Pathologists Who Treat EILO

PURPOSE

Swimmers present a unique challenge for the clinician when presenting with a diagnosis of exercise-induced laryngeal obstruction (EILO). The purpose of this tutorial was to query competitive swimmers about commonly used breathing strategies and then use that information as a basis from which to provide speech-language pathologists who treat EILO in swimmers with a clinical perspective for treatment planning and implementation.

METHODS

A survey of competitive female and male swimmers aged 18 and over was conducted to inquire about swim breathing techniques used in the context of swim distance(s), training versus competition, bilateral versus unilateral head turn, and stroke-to-breath ratio. Questions regarding experience with EILO and asthma were also included.

RESULTS

Following receipt of consent, 62 competitive swimmers completed the survey. The survey results indicated a preference for trickle breathing; however, many volunteers described different breathing strategies for training versus competition. Breath-to-stroke ratios differed widely, often based on swim distance as a means to have competitive advantage. Thirteen volunteers reported difficulty inhaling while swimming, two of whom reported a diagnosis of EILO and one who reported a diagnosis of asthma.

CONCLUSIONS

Swimmers with EILO present with unique challenges for clinicians, given the various breathing techniques used and the idiosyncratic nature of breathing strategies for each swimmer. A one-size-fits-all approach is insufficient for this population and clinicians interested in treating swimmers with EILO will need to employ optimal critical thinking skills for intervention success-a true merger of art and deep understanding of respiratory and laryngeal physiology.

Hypotussic cough in persons with dysphagia: biobehavioral interventions and pathways to clinical implementation

Cough is a powerful, protective expulsive behavior that assists in maintaining respiratory health by clearing foreign material, pathogens, and mucus from the airways. Therefore, cough is critical to survival in both health and disease. Importantly, cough protects the airways and lungs from both antegrade (e.g., food, liquid, saliva) and retrograde (e.g., bile, gastric acid) aspirate contents. Aspiration is often the result of impaired swallowing (dysphagia), which allows oral and/or gastric contents to enter the lung, especially in individuals who also have cough dysfunction (dystussia). Cough hyposensitivity, downregulation, or desensitization- collectively referred to as hypotussia- is common in individuals with dysphagia, and increases the likelihood that aspirated material will reach the lung. The consequence of hypotussia with reduced airway clearance can include respiratory tract infection, chronic inflammation, and long-term damage to the lung parenchyma. Despite the clear implications for health, the problem of managing hypotussia in individuals with dysphagia is frequently overlooked. Here, we provide an overview of the current interventions and treatment approaches for hypotussic cough. We synthesize the available literature to summarize research findings that advance our understanding of these interventions, as well as current gaps in knowledge. Further, we highlight pragmatic resources to increase awareness of hypotussic cough interventions and provide support for the clinical implementation of evidence-based treatments. In culmination, we discuss potential innovations and future directions for hypotussic cough research.

Efficacy of behavioral cough suppression therapy for refractory chronic cough or unexplained chronic cough: a meta-analysis of randomized controlled trials

BACKGROUND

The efficacy of behavioral cough suppression therapy (BCST) for refractory chronic cough (RCC) and unexplained chronic cough (UCC) remains unclear due to limited evidence from small-scale single-center studies.

OBJECTIVE

To compile and assess the quality of evidence from randomized controlled trials to evaluate the effectiveness of BCST.

DESIGN

This study included randomized controlled studies and self-controlled studies related to BCST involving adult patients with RCC or UCC.

DATA SOURCES AND METHODS

We conducted an extensive search of various English and Chinese databases (e.g., PubMed, CNKI, CBM, VIP, and Wanfang Data Journal Full-text Database) and the Clinical Trial Registration website up to April 2024. The selected studies underwent meta-analysis to investigate the impact of BCST on the patient's quality of life and cough frequency.

RESULTS

The included 12 studies showed that BCST significantly improved the Leicester Cough Questionnaire scores of the patients (MD = 4.50, 95% CI (4.03, 4.97), p < 0.001) compared to the simple verbal education group. In addition, a significant reduction in objective cough frequency was observed in patients compared to before BCST, with a statistically significant difference (MD = -8.06, 95% CI (-9.71, -6.41), p < 0.001). Other measures of cough symptoms, such as symptom scores, Visual Analog Scale (VAS) scores, and Cough Severity Index (CSI) also showed improvement.

CONCLUSION

This meta-analysis revealed positive therapeutic effects of BCST in patients with RCC/UCC, potentially advancing its application in broader clinical settings.

TRIAL REGISTRATION

This study was registered on PROSPERO with the registration number CRD42024530746.

Legacies of salient environmental experiences-insights from chemosensation

Evidence for parental environments profoundly influencing the physiology, biology, and neurobiology of future generations has been accumulating in the literature. Recent efforts to understand this phenomenon and its underlying mechanisms have sought to use species like rodents and insects to model multi-generational legacies of parental experiences like stress and nutritional exposures. From these studies, we have come to appreciate that parental exposure to salient environmental experiences impacts the cadence of brain development, hormonal responses to stress, and the expression of genes that govern cellular responses to stress in offspring. Recent studies using chemosensory exposure have emerged as a powerful tool to shed new light on how future generations come to be influenced by environments to which parents are exposed. With a specific focus on studies that have leveraged such use of salient chemosensory experiences, this review synthesizes our current understanding of the concept, causes, and consequences of the inheritance of chemosensory legacies by future generations and how this field of inquiry informs the larger picture of how parental experiences can influence offspring biology.

Characterization of Ethyl Butyrate-Induced Cough Before and After Breath Control Techniques in Healthy Adults

PURPOSE

Methods for cough elicitation frequently involve aerosolized tussive agents. Here, we sought to determine whether healthy individuals demonstrate a quantifiable cough response after inhaling a volatile ester and if breath control techniques modify this chemically induced cough response.

METHOD

Sixty adult male and female participants inhaled prepared liquid dilutions of ethyl butyrate dissolved in paraffin oil at 20%, 40%, and 60% v/v concentrations in triplicate, with presentation order randomized. We delivered stimuli through a face mask connected to an olfactometer and respiratory pneumotachograph. Participants rated sensations of their urge to cough and pleasantness of the odor while cough airflow was measured. Following baseline testing, participants were randomized to implement pursed-lip breathing or slow-paced breathing after inhaling ethyl butyrate to determine the effects of breath control on cough measures.

RESULTS

Inhaled ethyl butyrate elicited cough in 70% of participants. Higher concentrations of ethyl butyrate resulted in significantly greater sensation of the urge to cough, F(2, 80) = 10.72, p < .001, and significantly more generated coughs, F(2, 63) = 13.14, p < .001. Compared to baseline, participants rated significantly decreased urge to cough during breath control techniques, F(1, 40) = 11.01, p = .0019. No significant changes were observed in the number of generated coughs between baseline and breath control techniques, F(1, 31) = 7.23, p = .01.

CONCLUSIONS

Airborne ethyl butyrate is a tussigenic agent in humans. Our findings provide opportunities for future research directions in normal and disordered cough responses to volatile compounds.

Olfactory and gustatory disorders caused by COVID-19: How to regain the pleasure of eating?

Background

Recently, anosmia and ageusia (and their variations) have been reported as frequent symptoms of COVID-19. Olfactory and gustatory stimuli are essential in the perception and pleasure of eating. Disorders in sensory perception may influence appetite and the intake of necessary nutrients when recovering from COVID-19. In this short commentary, taste and smell disorders were reported and correlated for the first time with food science.

Scope and approach

The objective of this short commentary is to report that taste and smell disorders resulted from COVID-19 may impact eating pleasure and nutrition. It also points out important technologies and trends that can be considered and improved in future studies.

Key findings and conclusions

Firmer food textures can stimulate the trigeminal nerve, and more vibrant colors are able to increase the modulation of brain metabolism, stimulating pleasure. Allied to this, encapsulation technology enables the production of new food formulations, producing agonist and antagonist agents to trigger or block specific sensations. Therefore, opportunities and innovations in the food industry are wide and multidisciplinary discussions are needed.

Multiple Chemical Sensitivity

Multiple Chemical Sensitivity (MCS), a condition also known as Chemical Sensitivity (CS), Chemical Intolerance (CI), Idiopathic Environmental Illness (IEI) and Toxicant Induced Loss of Tolerance (TILT), is an acquired multifactorial syndrome characterized by a recurrent set of debilitating symptoms. The symptoms of this controversial disorder are reported to be induced by environmental chemicals at doses far below those usually harmful to most persons. They involve a large spectrum of organ systems and typically disappear when the environmental chemicals are removed. However, no clear link has emerged among self-reported MCS symptoms and widely accepted objective measures of physiological dysfunction, and no clear dose-response relationship between exposure and symptom reactions has been observed. In addition, the underlying etiology and pathogenic processes of the disorder remain unknown and disputed, although biologic and psychologic hypotheses abound. It is currently debated whether MCS should be considered a clinical entity at all. Nevertheless, in the last few decades MCS has received considerable scientific and governmental attention in light of the many persons reporting this illness. In this review, we provide a general overview of the history, definition, demographics, prevalence, and etiologic challenges in defining and understanding MCS.