Normal Cough Research Articles

Fecal incontinence patients categorized based on anal pressure and electromyography: Anal sphincter damage and clinical symptoms.

Disruption of external anal sphincter muscle (EAS) is an important factor in the multifactorial etiology of fecal incontinence (FI). We categorize FI patients into four groups based on the location of lesion in neuromuscular circuitry of EAS to determine if there are differences with regards to fecal incontinence symptoms severity (FISI) score, age, BMI, obstetrical history, and anal sphincter muscle damage. Female patients (151) without any neurological symptoms, who had undergone high-resolution manometry, anal sphincter EMG, and 3D ultrasound imaging of the anal sphincter were assessed. Patients were categorized into four groups: Group 1 (normal)-normal cough EMG (>10 μV), normal squeeze EMG (>10 μV), and normal anal squeeze pressure (>124 mmHg); Group 2 (cortical apraxia, i.e., poor cortical activation)-normal cough EMG, low squeeze EMG, and low anal squeeze pressure; Group 3 (muscle damage)-normal cough EMG, normal squeeze EMG, and low anal squeeze pressure; and Group 4 (pudendal nerve damage)-low cough EMG, low squeeze EMG, and low anal squeeze pressure. The four patient groups were not different with regards to the patient's age, BMI, parity, and FISI scores. 3D ultrasound images of the anal sphincter complex revealed significant damage to the internal anal sphincter, external anal sphincter, and puborectalis muscles in all four groups. The FI patients are a heterogeneous group; majority of these patients have significant damage to the muscles of the anal sphincter complex. Whether biofeedback therapy response is different among different patient groups requires study.

Cervical percutaneous interferential current stimulation improves citric acid cough tests in patients with Parkinson’s disease on medication

Aspiration pneumonia is the leading cause of death in patients with Parkinson’s disease. The incidence of silent aspiration is high in such patients owing to decreased pharyngeal and laryngeal sensation; thus, interventions for this condition may help prevent pneumonia. In this single-arm, open-label study, we used a cervical percutaneous interferential current stimulation device to activate pharyngeal and laryngeal sensory nerves. We evaluated its effectiveness in patients with Hoehn–Yahr stages 2–4 Parkinson’s disease. The primary endpoint was the proportion of patients with a normal cough reflex after consuming 1% citric acid at the end of the intervention compared with baseline measurements. In total, 25 patients received neck percutaneous interferential current stimulation for 20 min twice weekly for 8 weeks. Afterward, the proportion of patients with a normal cough reflex after 1% citric acid consumption increased significantly (p = 0.001), whereas other indicators, such as tongue pressure, peak expiratory flow, and penetration or aspiration during videofluoroscopic examination, remained unchanged. A longer duration of illness, higher Unified Parkinson’s Disease Rating Scale total scores, and higher levodopa equivalent daily doses were significantly associated with improved cough test outcomes. Hence, cervical percutaneous interferential current stimulation significantly improved cough reflexes and may improve silent aspiration. Trial Registration: Japan Registry of Clinical Trials, jRCTs062220013, first registered 09/05/2022.

Cough: An Introductory Guide for Speech-Language Pathologists

Purpose: The airway defense mechanism of cough is essential for human survival. Recognition is growing about the distinct role of speech-language pathologists in the nonpharmacological management of various cough disorders. This clinical focus article aims to deliver relevant education about normal and pathological cough to strengthen existing clinical knowledge and skills. Conclusions: The neuronal pathways underlying normal cough function are complex. Cough problems refer to either reduced or heightened cough stemming from various disease processes, and both clinical presentations have detrimental consequences. Current evidence supports that patients who suffer from cough dysfunction benefit from nonpharmacological interventions offered via speech therapy as an adjunct to medical treatments. Speech therapy strategies apply the higher cognitive components of cough by focusing on the deliberate modification and coordination of respiration. Future research priorities are positioned toward improving clinical outcomes for cough disorders.

Impact of neck percutaneous interferential current sensory stimulation on swallowing function in patients with Parkinson's disease: A single-arm, open-label study protocol

BackgroundParkinson's disease (PD) can lead to swallowing dysfunction, resulting in aspiration pneumonia. Among the types of swallowing disorders, a characteristic and serious problem associated with PD is silent aspiration due to pharyngeal and laryngeal hypoesthesia. MethodsThis single-arm, open-label study aims to evaluate the effectiveness of percutaneous neck interferential current sensory stimulation in enhancing swallowing function in patients with PD. The efficacy and safety of percutaneous neck interferential current sensory stimulation will be investigated for patients diagnosed with PD, based on the Movement Disorder Society criteria, of Hoehn–Yahr stages 2–4. The patients will receive neck percutaneous interferential current sensory stimulation for 20 min twice a week for 8 weeks using a Gentle Stim® (FoodCare Co., Ltd., Kanagawa, Japan) device. Once the intervention is initiated, evaluations will be performed every 4 weeks for a 16-week period. The primary endpoint to be assessed is the proportion of patients with normal cough with 1% citric acid at the end of the intervention (8 weeks after intervention initiation) compared with that at the beginning. This clinical trial will examine the usefulness of percutaneous neck interferential current sensory stimulation in patients with PD. In addition, this study will use novel instruments, such as multichannel surface electromyography and electronic stethoscope, to evaluate swallowing function. DiscussionThis novel evaluation can provide insights into dysphagia in patients with PD and the usefulness of percutaneous neck interferential current stimulation. This exploratory study is limited by its single-arm, open-label design and small size. Trial registration numberjRCTs062220013; pre-results.

Nebulised hypertonic saline solution for acute bronchiolitis in infants.

Nebulised hypertonic saline solution for acute bronchiolitis in infants.

One-Step Fabrication of Paper-Based Inkjet-Printed Graphene for Breath Monitor Sensors

Irregularities in breathing patterns can be detected using breath monitor sensors, and this help clinicians to predict health disorders ranging from sleep disorders to heart failures. Variations in humidity during the inhalation and exhalation of breath have been utilized as a marker to detect breath patterns, and graphene-based devices are the favored sensing media for relative humidity (RH). In general, most graphene-based RH sensors have been used to explore resistance change as a measurement parameter to calibrate against the RH value, and they are prone to noise interference. Here, we fabricated RH sensors using graphene ink as a sensing medium and printed them in the shape of interdigital electrodes on glossy paper using an office inkjet printer. Further, we investigated the capacitance change in the sensor for the RH changes in the range of 10-70%. It exhibited excellent sensitivity with 0.03 pF/% RH, good stability, and high intraday and interday repeatability, with relative standard deviations of 1.2% and 2.2%, respectively. Finally, the sensor was embedded into a face mask and interfaced with a microcontroller, and capacitance change was measured under three different breathing situations: normal breathing, deep breathing, and coughing. The result show that the dominant frequency for normal breath is 0.22 Hz, for deep breath, it is 0.11 Hz, and there was no significant dominant cough frequency due to persistent coughing and inconsistent patterns. Moreover, the sensor exhibited a short response and recovery time (<5 s) during inhalation and exhalation. Thus, the proposed paper-based RH sensor is promising wearable and disposable healthcare technology for clinical and home care health applications.

Investigation on forced vibration characteristics of Nitinol tracheal stent.

Tracheal stents can be placed in a narrow position in the human trachea to ensure smooth breathing. And the stent will deform during service by the influence of the physiological environment or random excitations, such as coughing. This paper divides the vibration into periodic and random vibrations according to the different pressures. And a coupling vibration model was established by analyzing the contact relationship between the stent and the trachea tissue. And this study discusses the influence of tracheal diameter, respiratory pressure, and frequency on the stent vibration characteristics through Ansys simulation. In addition, the nonlinear equations were solved by the Matlab numerical analysis method, which could help analyze the influence of cough intensity on the stability of the tracheal stent system. The results showed that when tracheal stenosis occurred in the trachea's more significant grade, the trachea stent was more likely to fall off when treated with a tracheal stent. With the increase in respiratory frequency and pressure, the deformation of the tracheal stent is more considerable. Moreover, the frequency of normal cough hardly affects the stability of the stent system, while the excitation force and damping coefficient value greatly influence the system. When the excitation force of the cough exceeds the critical importance of 20N, the tracheal stent is prone to fall off. This study comprehensively obtained the forced vibration characteristics of the stent under service conditions, which could make up for the shortage of the vibration theory of the stent. The results can provide a theoretical basis for predicting the possibility of stent loss in clinical treatment.

Effects of restoration of cough via spinal cord stimulation on subject quality of life

ObjectivesTo determine participant quality of life before and after use of the cough stimulation system (Cough System). DesignProspective assessment of life quality at 4 timepoints via questionnaire responses. SettingOut-patient hospital, United States. Participants28 subjects with spinal cord injury (SCI) completed life quality assessment questionnaires before and at the 28- 40- and 52-week timepoints following use of the Cough System. ResultsEach subject demonstrated significant clinical improvements in terms of restoration of an effective cough and ability to manage airway secretions with use of the Cough System. Positive airway pressures and peak expiratory airflows approached values associated with a normal cough. Related to cough/secretion management, use of this system also resulted less interference with family life and daily activities, less financial difficulties, less requirement for caregiver assistance, less stress, less embarrassment and greater control of their breathing problems (p < 0.01), for each comparison). There also significant improvements in that their overall health and quality of life (p < 0.01, for each comparison). Subjects also reported greater ease in breathing, restored ability to sneeze and enhanced mobility. The incidence of acute respiratory tract infections fell from 1.3 ± 0.3 to 0.2 ± 0.1 events/subject year (p < 0.01). Ten subjects developed mild hemodynamic effects consistent with autonomic dysreflexia that abated completely with continued use of the Cough System. Some subjects experienced mild leg jerks during SCS, which were well tolerated and abated completely with reduction in stimulus amplitude, No subjects reported bowel or bladder leakage. ConclusionUse of the Cough System by SCI subjects is a safe and efficacious method which significantly improves life quality and has the potential to reduce the mortality and morbidity associated with SCI.

Strategies for screening, occupational prevention, and management of COVID-19 in outpatient clinics in Shandong.

ObjectiveWe hope to analyze the information of outpatients in a tertiary care hospital during the epidemic of COVID-19, so as to formulate effective regulations for the prevention and control of COVID-19.MethodsWe collected information from outpatients from January 28, 2020 to March 2, 2020 and performed the statistical analysis.ResultsDuring the study period, there were more than 60,000 outpatients. Among them, 404 patients with a body temperature above 37.3°C who had not been to Wuhan and had no contact with people from Wuhan. There were 8 people who had contact with people from Wuhan, such as 4 people with fever, 3 people with normal body temperature but cough symptoms, and 1 person with normal body temperature and no other discomfort. There were 2 patients with high body temperature from the epidemic area in Wuhan, and one novel Coronavirus patient was confirmed as the final result.ConclusionDuring the COVID-19 pandemic, outpatient medical staff should enhance their awareness of protection, hospitals should standardize the outpatient COVID-19 prevention and control system, improve the prevention and emergency system, and reduce occupational exposure hazards and the occurrence of post-exposure infections.

Natural Herbs used in normal Cough and Cold Condition

Natural herb Ajwain, Trachyspermum ammi (L.) Sprague is an annual herbaceous plant belonging to the highly valued medicinally important family, Apiaceae the essential oil from the fruits [7] are the phenols, mainly thymol and some carvacrol. The Indian Pharmacopoeia requires ajowan oil to contain not less than 40 per cent thymol. The remainder of the oil is called 'thymene'. Thymene, which constitutes c.45 per cent of the oil, has the following composition: p-cymene, 50-55; gterpinene, 30-35; a- and ß-pinenes, 4-5; and dipentene, 4-6%. Presence of minute 'amounts of camphene, myrcene and D3-carene is also reported. Kapoor is a tree of many faces as it is a giant, stately forest tree, native of the wet forests of tropical and subtropical regions of Asia. The species Camphora, refer to camphor, an important chemical constituent present in the oil found in the tissues of tree. The botanical name is derived from Greek language. It derived from the word 'kinnamomon' which means spice. This herb is recorded in Sanskrit also. This is also used by Egyptians as early 1485 BC for embalming purposes. Camphor tree is native to China, India, Mongolia, Japan and Taiwan and a variety of this fragrant evergreen tree is grown in Southern United States; especially in FloridaMenthol, Thymol, Phenol, Salicylic acid and Naphthol are amongst the fragrant chemical constituents obtained from this plant. Campher, Campherol, Cineol, Camphene, dipentene, terpineol, candinene, safrole, camphorace, laurolitsine, reticuline etc. Menthol is a naturally occurring monoterpene alcohol that is extracted from oil of peppermint, corn mint, or other mint plants. It is known for its minty, cooling odor, and taste , Various constituents of peppermint oil are limonene (1.0-5.0%), cineole (3.5-14.0%), menthone (14.0-32.0%), menthofuran (1.0-9.0%), isomenthone (1.510.0%), menthyl acetate (2.8-10.0%), isopulegol (0.2%), menthol (55.0%), pulegone (4.0%) and carvone (max. 1.0%). All three herbs gives relief from cough and cold, throat irritation and treating bronchitis.

Identification of Pneumonia using The K-Nearest Neighbors Method using HOG Fitur Feature Extraction

Pneumonia is a wet lung disease. Pneumonia is generally caused by viruses, bacteria or fungi. Not infrequently Pneumonia can cause death. The K-Nearest Neighbors method is a classification method that uses the majority value from the closest k value category. At this time people are not too worried about pneumonia because this pneumonia has symptoms like a normal cough. However, fast and accurate information from health experts is also very necessary so that pneumonia symptoms can be recognized early and how to deal with them can also be done faster. In this study, researchers will diagnose pneumonia to obtain information quickly about the symptoms of pneumonia. This information will adopt human knowledge into computers designed to solve the problem of identifying pneumonia. In this study, the K-Nearest Neighbors method will be combined with the HOG Extraction Feature to identify pneumonia more accurately. The KNN classification used is Fine KNN, Cosine KNN, and Cubic KNN. Where will be seen how the value of accuracy, precision, recall, and fi-score. The results showed that the classification could run well on the Fine KKN, Cosine KNN, and Cubic KNN methods. Fine KNN has an accuracy rate of 80.67, Cosine KNN has an accuracy rate of 84,93333, and Cubic KNN has an accuracy rate of 83,13333. Fine KNN has precision, recall and f1-score values of 0.794842, 0.923706, and 0.854442. Cosine KNN has precision, recall and f1-score values of 0.803048, 0.954039, and 0.872056. Cubic KNN has precision, recall and f1-score values of 0.73388, 0.964561, and 0.833555. From the test results, positive and negative identification of pneumonia was found to be more accurate with the Cosine KNN classification which reached 84,93333.

Airway inflammation due to SARS-CoV-2

Although there has been a large number of studies focusing on the role of airways in coronavirus disease 2019 (COVID-19), the relationship still remains unclear. With the disruption of the defense mechanism of the airways, including the intact mucus barrier, ciliary activity, and normal cough reflex, sticky and difficult-to-remove sputum becomes the main problem and the cough becomes the main symptom. Although interferons are considered the main elements of the defense against the virus, the pathogenesis of COVID-19 is complex and cannot be elucidated with only elevated interferon levels; there is more. The progression of the disease is mainly determined by the type and the levels of interferons and the affected part of the respiratory system. The airways have an important role in the pathogenesis of COVID-19, as the microorganism uses the airways as a gateway to the body, being the first element of defense against the virus, the importance of its relationship with the immune system, and its importance in the treatment.

A numerical assessment of social distancing of preventing airborne transmission of COVID-19 during different breathing and coughing processes

The spread of the novel coronavirus disease (COVID-19) continues to show that geographic barriers alone cannot contain the virus. Asymptomatic carriers play a critical role in the nature of this virus, which is rapidly escalating into a global pandemic. Asymptomatic carriers can inadvertently transmit the virus through the air stream. Many diseases can infect human bodies with tiny droplets or particles that carry various viruses and bacteria that are generated by the respiratory system of infected patients. This article presents the numerical results of the spread of droplets or particles in a room. The proposed numerical model in this work takes into account the sedimentation of particles or droplets under the action of gravitational sedimentation and transport in the room during the process of breathing and sneezing or coughing. Three different cases are numerically investigated taking into account normal breathing and coughing or sneezing, respectively, and three different rates of particle ejection from the mouth are considered. Navier–Stokes equations for incompressible flows were used to describe three-dimensional air flow inside ventilated rooms. The influence of ventilation rate on social distancing is also computationally investigated. It was found that particles can move up to 5 m with a decrease in concentration in the direction of the air flow. The conclusions made in this work show that, given the environmental conditions, the two meter social distance recommended by WHO is insufficient.

SARS COV-2 virus-laden droplets coughed from deep lungs: Numerical quantification in a single-path whole respiratory tract geometry.

When an infected person coughs, many virus-laden droplets will be exhaled out of the mouth. Droplets from deep lungs are especially infectious because the alveoli are the major sites of coronavirus replication. However, their exhalation fraction, size distribution, and exiting speeds are unclear. This study investigated the behavior and fate of respiratory droplets (0.1–4 μm) during coughs in a single-path respiratory tract model extending from terminal alveoli to mouth opening. An experimentally measured cough waveform was used to control the alveolar wall motions and the flow boundary conditions at lung branches from G2 to G18. The mouth opening was modeled after the image of a coughing subject captured using a high-speed camera. A well-tested k-ω turbulence model and Lagrangian particle tracking algorithm were applied to simulate cough flow evolutions and droplet dynamics under four cough depths, i.e., tidal volume ratio (TVR) = 0.13, 0.20. 0.32, and 0.42. The results show that 2-μm droplets have the highest exhalation fraction, regardless of cough depths. A nonlinear relationship exists between the droplet exhalation fraction and cough depth due to a complex deposition mechanism confounded by multiscale airway passages, multiregime flows, and drastic transient flow effects. The highest exhalation fraction is 1.6% at the normal cough depth (TVR = 0.32), with a mean exiting speed of 20 m/s. The finding that most exhaled droplets from deep lungs are 2 μm highlights the need for more effective facemasks in blocking 2-μm droplets and smaller both in infectious source control and self-protection from airborne virus-laden droplets.

Symptomatic manifestations of the disease caused by coronavirus (COVID-19) in adults: systematic review.

To identify symptoms of COVID-19 in adults in the scientific literature. Systematic review of studies published from December 1, 2019 to April 21, 2020 from the Scopus, Web of Science and PubMed databases, in order to answer the following research question: "What are the symptoms caused by COVID-19 in adults?" using the keywords "Symptoms", "Clinical Manifestations", "Coronavirus", "COVID-19". Of the total 105 references, 13 references that addressed the symptoms of COVID-19 were selected. Fever and normal or dry cough were symptoms present in all studies. The symptoms identified in adult patients were fever, normal or dry cough, headache, pharyngalgia, dyspnea, diarrhea, myalgia, vomiting, sputum or expectoration, anxiety or chest pain, fatigue, nausea, anorexia, abdominal pain, rhinorrhea, runny nose or nasal congestion, dizziness, chills, systemic pain, mental confusion, hemoptysis, asthma, taste disorder, smell disorder, belching and tachycardia.

Aerosol Generation from the Respiratory Tract with Various Modes of Oxygen Delivery.

Rationale: Aerosol generation with modes of oxygen therapy such as high-flow nasal cannula and noninvasive positive-pressure ventilation is a concern for healthcare workers during the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic. The amount of aerosol generation from the respiratory tract with these various oxygen modalities is unknown.Objectives: To measure the size and number concentration of particles and droplets generated from the respiratory tract of humans exposed to various oxygen delivery modalities.Methods: Ten healthy participants with no active pulmonary disease were enrolled. Oxygen modalities tested included nonhumidified nasal cannula, face mask, heated and humidified high-flow nasal cannula, and noninvasive positive-pressure ventilation. Aerosol generation was measured with each oxygen mode while participants performed maneuvers of normal breathing, talking, deep breathing, and coughing. Testing was conducted in a negative-pressure room. Particles with a diameter between 0.37 and 20 μm were measured using an aerodynamic particle spectrometer.Measurements and Main Results: Median particle concentration ranged from 0.041 to 0.168 particles/cm3. Median diameter ranged from 1.01 to 1.53 μm. Cough significantly increased the number of particles measured. Measured aerosol concentration did not significantly increase with the use of either humidified high-flow nasal cannula or noninvasive positive-pressure ventilation. This was the case during normal breathing, talking, deep breathing, and coughing.Conclusions: Oxygen delivery modalities of humidified high-flow nasal cannula and noninvasive positive-pressure ventilation do not increase aerosol generation from the respiratory tract in healthy human participants with no active pulmonary disease measured in a negative-pressure room.

Aerosol Exposure During Surgical Tracheotomy in SARS-CoV-2 Positive Patients.

Since December 2019, the novel coronavirus SARS-CoV-2 has been spreading worldwide. Since the main route of infection with SARS-CoV-2 is probably via contact with virus-containing droplets of the exhaled air, any method of securing the airway is of extremely high risk for the health care professionals involved. We evaluated the aerosol exposure to the interventional team during a tracheotomy in a semiquantitative fashion. In addition, we present novel protective measures. To visualize the air movements occurring during a tracheotomy, we used a breathing simulator filled with artificial fog. Normal breathing and coughing were simulated under surgery. The speed of aerosol propagation and particle density in the direct visual field of the surgeon were evaluated. Laminar air flow (LAF) in the OR reduced significantly the aerosol exposure during tracheostomy. Only 4.8 ± 3.4% of the aerosol was in contact with the surgeon. Without LAF, however, the aerosol density in the inspiratory area of the surgeon is 10 times higher (47.9 ± 10.8%, P < 0.01). Coughing through the opened trachea exposed the surgeon within 400 ms with 76.0 ± 8.0% of the aerosol-independent of the function of the LAF. Only when a blocked tube was inserted into the airway, no aerosol leakage could be detected. Coughing and expiration during a surgical tracheotomy expose the surgical team considerably to airway aerosols. This is potentially associated with an increased risk for employees being infected by airborne-transmitted pathogens. Laminar airflow in an operating room leads to a significant reduction in the aerosol exposure of the surgeon and is therefore preferable to a bedside tracheotomy in terms of infection prevention. Ideal protection of medical staff is achieved when the procedure is performed under endotracheal intubation and muscle relaxation.

Estimation of Viral Aerosol Emissions From Simulated Individuals With Asymptomatic to Moderate Coronavirus Disease 2019

Individuals with asymptomatic or mild coronavirus disease 2019 (COVID-19) have been reported to frequently transmit the disease even without direct contact. The severe acute respiratory syndrome coronavirus 2 has been found at very high concentrations in swab and sputum samples from such individuals. To estimate the virus levels released from individuals with asymptomatic to moderate COVID-19 into different aerosol sizes by normal breathing and coughing, and to determine what exposure could result from this in a room shared with such individuals. This mathematical modeling study combined the size-distribution of exhaled breath microdroplets for coughing and normal breathing with viral swab and sputum concentrations as approximation for lung lining liquid to obtain an estimate of emitted virus levels. Viral data were obtained from studies published as of May 20, 2020. The resulting emission data fed a single-compartment model of airborne concentrations in a room of 50 m3, the size of a small office or medical examination room. Modeling was used to estimate the viral load emitted by individuals breathing normally or coughing, and the concentrations expected in the simulated room at different ventilation rates. The mean estimated viral load in microdroplets emitted by simulated individuals while breathing regularly was 0.0000049 copies/cm3, with a range of 0.0000000049 to 0.637 copies/cm3. The corresponding estimates for simulated coughing individuals were a mean of 0.277 copies/cm3 per cough, with a range of 0.000277 to 36 030 copies/cm3 per cough. The estimated concentrations in a room with an individual who was coughing frequently were very high, with a maximum of 7.44 million copies/m3 from an individual who was a high emitter. However, regular breathing from an individual who was a high emitter was modeled to result in lower room concentrations of up to 1248 copies/m3. In this modeling study, breathing and coughing were estimated to release large numbers of viruses, ranging from thousands to millions of virus copies per cubic meter in a room with an individual with COVID-19 with a high viral load, depending on ventilation and microdroplet formation process. The estimated infectious risk posed by a person with typical viral load who breathes normally was low. The results suggest that only few people with very high viral load pose an infection risk in poorly ventilated closed environments. These findings suggest that strict respiratory protection may be needed when there is a chance to be in the same small room with an individual, whether symptomatic or not, especially for a prolonged period.

Sustainability of SARS-CoV-2 in aerosols: should we worry about airborne transmission?

Sustainability of SARS-CoV-2 in aerosols: should we worry about airborne transmission?

Approach to the Patient with Cough

The cough reflex is critically important in the clearance of abnormal airway secretions and protection of the lower respiratory tract from aspirated foreign matter. A weak or ineffective cough can lead to respiratory compromise from even a relatively minor bronchial infection. Persistent cough is often one of a constellation of symptoms indicative of respiratory disease—a potential clue in the differential diagnosis of the patient’s illness. Given the widespread distribution of sensory nerve endings of the cough reflex throughout the upper and lower respiratory tract, it is not surprising that myriad respiratory diseases, involving lung parenchyma and airways, can manifest with cough. Sometimes cough is the sole or predominant symptom in a patient who is otherwise well. Evaluating and treating the patient with persistent cough who has few, if any, other respiratory symptoms is a common challenge for the practicing physician. This review covers the normal cough mechanism, impaired cough, pathologic cough, cough suppressant therapy, and new developments. Figures show a flow-volume loop during cough, a posteroanterior chest x-ray in a patient presenting with chronic cough, flow-volume curves and spirograms documenting expiratory airflow obstruction, and the approach to the patient with chronic cough. The table lists selected examples of extrapulmonary physical findings of potential importance in the assessment of cough. This review contains 4 highly rendered figures, 1 table, and 94 references.