Clinical Research Directory

Mechanisms of Change in Behavioral Cough Suppression Therapy for Refractory Chronic Cough

This study is testing new ways to help people who have chronic cough that has not improved with typical treatments. One approach is called behavioral cough suppression (BCS) therapy, which teaches people techniques to stop themselves from coughing. Another approach uses a natural substance found in chili peppers (capsaicin) to help reduce the body's sensitivity to cough triggers. In this study, we will test two treatments and include one no-treatment control group. The control group will undergo baseline testing, cough monitoring, and an fMRI brain scan and will be offered BCS at end of study participation. The two treatments include: * BCS therapy with capsaicin (BCS+CAP), * BCS therapy with a placebo (BCS+Sham), The investigators will enroll 135 adults with refractory chronic cough (RCC). 100 participants who qualify and are willing and able to complete 14 study visits in the clinic and two online study visits will be randomly assigned to one of the two treatments. The no-treatment control group (n=35) will be recruited from adults with RCC who are willing to complete baseline testing and fMRI but are not able or willing to attend 14 study clinic visits. These participants will not be randomized. The investigators want to find out how these treatments affect: * How sensitive someone is to things that make them cough, * How well they can hold back a cough when they try, * How their brain responds to things that cause an urge-to-cough, * And how much their coughing affects their quality of life. The investigators believe both treatments will reduce sensitivity to cough stimulants, reduce cough severity, and improve quality of life, but BCS+CAP treatment will work better than. BCS+Sham.

Canadian Consortium on Airway Mucus Occlusions in Asthma, COPD and Chronic Cough

Chronic lung diseases affect one in five Canadians, causing symptoms such as cough, breathlessness, and wheeze. Despite advancements in medical care, these conditions not only impact individuals and their close circles but also present substantial clinical and economic challenges at a national level. This grant is dedicated to addressing three prevalent lung diseases: asthma, chronic obstructive pulmonary disease (COPD), and chronic cough. An alliance of clinicians, scientists, knowledge users, and patient partners from across Canada have come together to establish the Canadian Consortium for Understanding the Role of Airway Mucus Occlusions in Asthma, COPD, and Chronic Cough - "CANMuc." Mucus plays a pivotal role in the symptoms and severity of lung diseases, but its clinical assessment has been challenging. Fortunately, recent medical advances, particularly chest computed tomography (CT), facilitate visualizing and quantifying mucus in patients with lung diseases. Our goal is to initially assess mucus plugging in a diverse group of Canadians without lung disease and then compare these findings to those with asthma, COPD, and chronic cough. The investigators will recruit 100 healthy volunteers for comprehensive clinical and research evaluations, including sputum analyses, breathing tests, quality of life assessments, cough monitoring, and CT scans. In addition, testing will be conducted twice, two years apart, in 240 adult and 50 pediatric participants. This approach will enable the investigators to understand the burden of mucus and how it changes over time, explore proteins or chemicals in mucus that predict mucus persistence, and identify biomarkers that can help guide physicians to prescribe targeted treatments that might work better than others. The CANMuc team's findings will guide strategies for identifying and treating mucus plugging, inform policymakers, and share knowledge with Canadians living with asthma, COPD, and chronic cough.

Wenjuanxing-Based Multidimensional Etiologic Screening and Clinical Validation of Chronic Cough in Children

Chronic cough is a common and burdensome condition in children, with complex and overlapping etiologies that often lead to delayed diagnosis, misdiagnosis, and inappropriate treatment. This prospective, controlled, observational study aims to develop and clinically validate a Wenjuanxing-based, parent-reported, multidimensional etiologic screening questionnaire for pediatric chronic cough. Children aged 3-18 years presenting with cough lasting ≥2 weeks will be enrolled in a tertiary pediatric respiratory clinic and allocated to either a routine-care group or a questionnaire-assisted group. All caregivers will complete the standardized electronic questionnaire, which generates an automated preliminary etiologic suggestion based on symptom patterns, triggers, and associated features. Diagnostic accuracy, treatment effectiveness, and symptom resolution will be evaluated through structured follow-up at two weeks. The primary outcome is the difference in diagnostic accuracy between physicians using routine assessment alone and those supported by the questionnaire. Secondary outcomes include treatment response and prevention of cough chronicity. This study seeks to provide evidence for a scalable, digital, and standardized screening tool to improve early etiologic identification and clinical decision-making in pediatric chronic cough.

The Safety, Feasibility, and Repeatability of Inhaled ATP Cough Challenges

The inhalation of adenosine 5'-triphosphate (ATP) to evoke cough (ATP cough challenge) is becoming increasingly used as a tool to measure cough hypersensitivity in patients with chronic cough. However, the safety, feasibility, and repeatability of this procedure is not widely known. In this study, we will perform ATP cough challenges in healthy individuals and in patients with mild asthma and chronic cough to better understand the safety, feasibility, and repeatability of these challenges. Such information will guide the future conduct of ATP cough challenges to measure cough hypersensitivity and identify patients who may better respond to ATP-blocking therapies.

Efficacy of Intramuscular Steroid Injection for Chronic Cough.

The primary goal of this study is to test the hypothesis that injecting steroid intramuscularly is an effective treatment for unexplained chronic cough. This will be achieved through the design of a prospective, placebo-controlled, single-blind, randomized clinical trial in which one group of patients will undergo a steroid injection into the deltoid muscle and the second group will undergo a placebo injection into the deltoid muscle. Data to determine if a clinically significant difference exists between the outcomes of the two groups will be measured by a dichotomous yes/no response to improvement, the Leicester Cough Questionnaire, and a visual analogue scale for symptom severity. This will provide the answer to the general question of whether or not the intramuscular injections are clinically effective for patients with unexplained chronic cough. Furthermore, any adverse reactions will be thoroughly documented. If this hypothesized treatment is proven effective, this can greatly improve the care of chronic cough patients by allowing for an evidence-based treatment option and a treatment option that may improve access to care. While the superior laryngeal nerve (SLN) injection is typically performed by fellowship trained laryngologists, intramuscular injections could be more widely utilized by general otolaryngologists or providers in other fields of medicine.

Investigating the Role of ATP Production by Airway Epithelium in Patients With Refractory and Unexplained Chronic Cough (RCC/UCC).

Chronic cough is a common troublesome symptom which has a global prevalence of approximately 10%, but with wide variations across continents. Patients with refractory and unexplained chronic cough (RCC/UCC) often exhibit dysregulated vagal pathways, necessitating a neuronal biomarker for targeted treatment. ATP, involved in the ATP/P2X3 pathway, may serve as a potential biomarker due to its role in the cough reflex. The study aims to discover if ATP production by the airway epithelium is greater in RCC/UCC patients compared with healthy controls, if the epithelium is a source of ATP, whether gene and protein expression related to ATP production differs between these groups and whether ATP release is triggered by mechanical and chemical stimulation. Additionally, the study seeks to determine if biomarker gene expression signatures can differentiate RCC/UCC patients from healthy controls.

China Chronic Cough Registry: a Multicenter, Prospective, Observational Study

The aim is to establish a national clinical database and biobanks for chronic coughers. Through real-world chronic cough case registry and follow-up studies, we will explore the clinical phenotypes and molecular subtypes of chronic cough.

Impact of Chronic Cough on Activities of Daily Living and Response to Acute High-intensity Exercise

Chronic cough is a common and debilitating condition that affects up to 10% of the global population. The health impact of chronic cough is multifaceted and manifests both physical and psychological symptoms including syncope, chest pain, lethargy, depression and anxiety. It is now also recognised that chronic cough often leads to social isolation and may impact an individual's ability or confidence to undertake routine daily tasks / lead an active lifestyle. The primary aim of this study is therefore to characterise the impact of unexplained chronic cough on the ability to undertake daily activities - i.e., determine whether individuals with chronic cough exhibit impaired levels of physical activity during usual daily living when compared with healthy age, gender and BMI matched controls. A secondary aim is to assess the short-term impact of high-intensity exercise on cough (i.e., determine whether an acute bout of exercise alters cough frequency and/or severity).