Cough: An Introductory Guide for Speech-Language Pathologists
Publication: Perspectives of the ASHA Special Interest Groups
Volume 9, Number 1
Pages 75-91
Abstract
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.
Following the Scope of Practice in Speech-Language Pathology (American Speech-Language-Hearing Association [ASHA], 2016) and practice portal clinical topics of ASHA (adult dysphagia [ASHA, n.d.-a]; aerodigestive disorders [ASHA, n.d.-b]; voice disorders [ASHA, n.d.-c), cough disorders fall under the professional service delivery areas of speech-language pathologists. Speech-language pathologists assess and treat diminished cough as a sequela of neurodegenerative diseases (Hegland & Sapienza, 2013). They also encounter complex cases of chronic cough following extensive medical workup and failed treatments (Vertigan & Gibson, 2012). There is growing recognition of the beneficial role of speech therapy for disordered cough across the wide range of abnormal cough function (Gibson et al., 2016; Soni et al., 2017; Visca et al., 2020; Wamkpah et al., 2022; Watts et al., 2016). It is reasonable to anticipate that speech-language pathologists will continue to receive increased cough-related patient referrals. As such, continuing education platforms are needed to refine clinical competencies and skills regarding cough and other respiratory functions (Birring et al., 2017; Gaziano & Serrano, 2012; Mir & Hegland, 2021; Novaleski, Doty, et al., 2023). This clinical focus article aims to enhance the breadth of clinical knowledge in cough by addressing the significance of cough function, neuronal pathways of cough, and mechanics of cough physiology. Moreover, we describe the major classifications of cough disorders, nonpharmacological interventions for disordered cough, and future directions in cough research.
Basics of Cough
Why Is Cough Important?
The respiratory act of coughing allows breathing to occur without obstruction and is necessary to protect the lower airways (Murgia et al., 2020). For these reasons, cough is considered a normal, life-sustaining physiological reflex (Driessen et al., 2020). Individuals cough as a reaction to the presence of potentially dangerous materials in the airways, most notably aspirated foods or liquids, inhaled irritants, and increased airway secretions (Mazzone & Farrell, 2019; Milgrom et al., 1990; Won et al., 2018). Cough is also involved in regulating the degree of inspiration and expiration to prevent lung overdistension in the presence of excess fluid accumulation (e.g., pulmonary edema) or collapse of the lungs (i.e., atelectasis; Brander et al., 2017; Milgrom et al., 1990). Thus, generating a timely and coordinated cough supports healthy respiratory function across the life span. In addition to being reflexive, cough is voluntarily controlled (P. C. L. Lee et al., 2002). Specifically, individuals can intentionally initiate, modify, augment, and inhibit cough (Davenport, 2009; Hegland & Sapienza, 2013). Higher level cognitive control of cough has numerous benefits. For instance, enhancing cough intensity is advantageous for airway clearance during swallowing to compensate for airway protection deficits (Pitts et al., 2008), while suppressing cough is critical when individuals must remain inconspicuous such as during military operations and active shooter incidents.
What Happens in the Nervous System During Cough?
Like all human behavior, cough occurs through a series of carefully orchestrated activities within the nervous system. The neuronal pathways that control reflexive cough are acknowledged as highly complex (Driessen et al., 2020). Beginning in the periphery, sensory neurons (or airway afferent nerve fibers) richly innervate the mucosa lining the airways and lungs. These airway sensory neurons detect various chemical and punctate mechanical stimuli that may pose potential threats to maintaining a patent airway (Mazzone, 2004). Airway sensory neurons, originating from the vagal sensory ganglia, are notably different in terms of the locations where they terminate (e.g., extrapulmonary vs. intrapulmonary airways) and their responsiveness to different types of stimuli (Mazzone & Farrell, 2019). More detailed reviews of airway sensory nerves can be found elsewhere (Canning et al., 2014; Mazzone & Undem, 2016).
An essential next step for cough requires encoding airway sensory inputs at the level of the central nervous system. In the ascending sensory pathway, airway sensory neurons derived from the nodose and jugular vagal ganglia project to the brainstem at the solitary and paratrigeminal nuclei, respectively (Driessen et al., 2020). Within the brainstem respiratory network, the breathing pattern is modified to produce the motor pattern of reflex cough (Mutolo, 2017). In addition to contributing to the motoric act of cough, airway sensory signals travel from the brainstem via ascending pathways to cortical and subcortical brain regions (Farrell et al., 2014; Mazzone & Farrell, 2019; Mazzone et al., 2007, 2011; Simonyan et al., 2007). These neural networks are collectively responsible for respiratory sensory processing and form the conscious awareness of airway irritation, as reviewed previously (Farrell & Mazzone, 2014; Mazzone et al., 2013). In particular, the urge to cough is a biological urge often perceived before the physical act of coughing, which is believed to motivate individuals further to want to clear the airways (Davenport, 2008).
In contrast to a reflex, a cough can be generated without chemical or mechanical stimulation in the periphery. Cognitive control of cough occurs via the descending cortical motor pathway, which engages respiratory musculature to create the motor sequence of cough (Mazzone & Farrell, 2019; Mazzone et al., 2011). The involvement of multiple higher brain regions during cough (e.g., primary and secondary somatosensory cortices, inferior frontal gyrus, midcingulate cortex; Farrell et al., 2012, 2014; Guo et al., 2023) permits individuals to willfully produce cough when desired (voluntary or volitional cough). Furthermore, higher cortical control of cough allows individuals to regulate the frequency and intensity of cough by augmenting, softening, and substituting it, even when chemically evoked (Brandimore et al., 2017; Hegland et al., 2012). As described by Davenport (2009), consciously paying attention to airway sensations can serve as a cue to change the cough response, including completely suppressing it in some instances (Hutchings et al., 1993).
Laboratory experiments provide convincing evidence that various cognitive factors influence cough responses when elicited as a reflex (e.g., chemically induced). In healthy adults, attending to the number of generated coughs temporarily leads to a greater frequency of coughing (Janssens et al., 2014), and believing that an inhaled chemical could be harmful increases the sensation of the urge to cough (Janssens et al., 2015). In contrast, the sensation of the urge to cough reduces in healthy volunteers when modifying breathing patterns (Novaleski, Hegland, et al., 2023) and anticipating that inhaling normal air is therapeutic (placebo; Leech et al., 2012, 2013). Similarly, mindfulness training alters cough reflex sensitivity in healthy individuals (Young et al., 2009). Attention also influences cough, as both the urge to cough and the quantified number of coughs downregulate while individuals are instructed to concentrate on two simultaneous tasks (Perry & Troche, 2019). Given the close interplay between cognitive processes and cough (Van den Bergh et al., 2012), uncertainty continues about the precise degree of higher level cognitive control of reflexive cough.
What Happens to the Body During Cough?
Cough physiology, or cough mechanics, involves three primary motoric phases: inspiration, compression, and expulsion (Widdicombe & Fontana, 2006). The cough starts with an initial inhalation during the inspiratory phase, in which the diaphragm contracts while the open or abducted vocal folds permit air to flow into the lungs (Amin & Belafsky, 2010; Fontana & Lavorini, 2006). During the subsequent compression phase, high tracheal pressures are generated via expiratory muscle contraction against a closed or adducted larynx (Amin & Belafsky, 2010; Simpson & Amin, 2006). In addition to primary glottic constriction, substantial compression occurs at the supraglottic level of the laryngeal vestibule, nasopharynx, and other sites (J. Y. Kim et al., 2023). A common quantifiable metric derived from a cough airflow signal obtained from spirometry is the compression phase duration or length of time the glottis remains closed (Pitts et al., 2008).
Finally, the expulsive phase involves abrupt vocal fold opening as expiratory muscles contract forcefully (Fontana, 2008). This maneuver ejects material from the lower airway into the pharynx or oral cavity (Pitts, 2014). Many measurements can be quantified during cough expulsion, namely, expiratory phase peak flow (highest point that airflow is expelled), expiratory phase rise time (length of time from the compression phase to peak flow), and cough volume acceleration (peak flow divided by rise time; Pitts et al., 2010). Please see Lowell et al. (2023) and Hegland and Sapienza (2013) for a more comprehensive review of cough airflow measurements. Figure 1 summarizes cough's functions, neural underpinnings, and physical mechanics. With a foundation now established about the basics of cough, we next concentrate on the clinical relevance of pathological cough.
Clinical Applications of Cough
What Are Cough Disorders?
Overall, disordered cough is a symptom that presents in various structural and neurological diseases (Al-Biltagi et al., 2022; Madison & Irwin, 2005; Zhou et al., 2022). Abnormal cough occurs along a spectrum of dysfunction (Spinou, 2018). Specifically, cough problems can range from the inability to safely protect the airway because of reduced cough (hypotussia) or absent cough (atussia; Pitts et al., 2008) to the psychosocial consequences of an incessant, heightened cough response (hypertussia; Morice, Jakes, et al., 2014). Whichever direction that cough is impaired, the health, societal, economic, and psychosocial implications of cough disorders are severe. As mentioned previously, reflex cough involves a sensory–perceptual experience known as the urge to cough (Davenport, 2008) and a reflexive motor pattern of respiratory modifications (Hegland & Sapienza, 2013). Some researchers incorporate these sensory and motor cough airflow components as clinical outcome measures for patients with pathological cough (Cho, Birring, et al., 2019; Lowell et al., 2023; Vertigan & Gibson, 2011; Watts et al., 2016; Zhang et al., 2022).
Hypotussia: A Problem of Impaired Airway Protection
The first classification of cough disorders is hypotussia, which many speech-language pathologists are familiar with due to its clinical relevance to dysphagia (Mir & Hegland, 2021). Hypotussive cough disorders refer to weakened cough production and can also be characterized by diminished airway sensations. Cough is critical to protect the airway, so similarities exist in the neural substrates and physiology between coughing and swallowing (Amin & Belafsky, 2010; Pitts, 2014; Pitts et al., 2013; Troche, Brandimore, Godoy, & Hegland, 2014). If an individual has reduced effectiveness of their cough function, serious concerns arise because impaired cough increases the risk of uncompensated or undercompensated aspiration (Troche, Brandimore, Okun, et al., 2014). There is growing evidence that patients, in particular those with neurodegenerative diseases, demonstrate impairments in both coughing and swallowing (Pitts et al., 2008). Additionally, there is expanding recognition that cough dysfunction may predict dysphagia severity (K. W. Lee et al., 2023; Silverman, Carnaby, et al., 2016; Troche et al., 2016). Therefore, enhanced understanding about cough function is well aligned with the established skill set of speech-language pathologists who assess and treat dysphagia. Consistent with cough involving multiple pathways in the nervous system, Al-Biltagi et al. (2022) conducted a useful comprehensive review of neurological disorders resulting in hypotussia.
Objective reductions in motor cough airflow measures have been observed in a variety of patient populations with neurological conditions, including Parkinson's disease (Silverman, Carnaby, et al., 2016), progressive supranuclear palsy (Borders et al., 2021), vocal fold paralysis (Murty et al., 1991), Pompe disease (Pitts et al., 2019), and poststroke (Hammond et al., 2001). Decreased cough airflow has also been characterized among patients with structural changes following treatment for head and neck cancer (Fullerton et al., 2021), total laryngectomy (Fullerton et al., 2020), and lung transplantation (Dallal-York et al., 2023). In addition, cough airflow metrics have expanded to evaluate changes in cough function following augmentation procedures for glottic insufficiency (Dion et al., 2017; Rameau et al., 2023; Ruddy et al., 2014). Along with the motor measurements of cough airflow, diminished sensation of the urge to cough has been documented in patients with neurogenic etiologies of hypotussia such as Parkinson's disease (Troche, Brandimore, Okun, et al., 2014; Troche et al., 2016) and traumatic brain injury with tracheostomy (Silverman, Sapienza, et al., 2016). The knowledge obtained from these studies provides the foundation for the subsequent implementation of nonpharmacological treatments for hypotussive cough disorders.
Hypertussia: A Problem of Quality of Life
On the opposite side of the cough spectrum is hypertussia. Hypertussia, or chronic cough, involves persistent and excessive coughing that is generally not life threatening (Irwin et al., 2020). Despite this, hypertussive responses have significant health consequences, most notably stress urinary incontinence (Ackah et al., 2022; Dicpinigaitis, 2021), rib fracture (Irwin et al., 2020), loss of consciousness (Schattner, 2020), social isolation (Everett et al., 2007), depression (Dicpinigaitis et al., 2006; Satia et al., 2022), and anxiety (Dicpinigaitis et al., 2022; McGarvey et al., 2023). As a result, hypertussia is a cough disorder that greatly impacts an individual's quality of life. Hypertussia has a lifetime prevalence of 8.2% (Dominguez-Ortega et al., 2022) and impacts an estimated 12.3 million individuals in the United States (Meltzer et al., 2021). Patients with hypertussia suffer on average for 11 years before being properly treated (Dicpinigaitis et al., 2022), leading to substantial health care utilization (Dominguez-Ortega et al., 2022; Meltzer et al., 2021) and high health care costs (Birring et al., 2021; Cho et al., 2022).
Objective cough airflow metrics reveal greater expiratory peak flow and longer compression phase duration in patients with hypertussia compared to healthy controls (K. K. Lee et al., 2015). An upregulated sensation of the urge to cough has also been reported in patients with hypertussia (Hilton et al., 2015). However, the primary clinical outcomes tend to focus on subjective self-report measures such as cough-related quality of life and cough symptom severity (Cho, Birring, et al., 2019; Dornelas et al., 2022; Kum et al., 2021; Turner & Birring, 2023; Zhang et al., 2022). Reiterating the notion that abnormal cough is a symptom, hypertussive responses are common presentations across many lung diseases (Dominguez-Ortega et al., 2022; McGarvey et al., 1998; Visca et al., 2020; Zeiger et al., 2020), notably asthma (Dávila et al., 2023; Zhou et al., 2022), chronic obstructive pulmonary disease (Deslee et al., 2016; Landt et al., 2020), and interstitial lung disease (Lan et al., 2021; Saari et al., 2023).
In contrast to hypertussia as a symptom observed in pulmonary disease, evidence has accumulated to support that neurological etiologies can cause airway dysfunction (Zaccone & Undem, 2016). A persistent cough can occur without pathology in the respiratory tract (Chung et al., 2013). A distinct syndrome is recognized, coined cough hypersensitivity syndrome, to describe hypertussive responses to stimuli that typically would not induce cough (Morice, 2010; Morice, Millqvist, et al., 2014). Such syndromes can occur for various reasons such as vitamin deficiency (Bucca et al., 2011) and following a viral infection (Undem et al., 2015). For instance, chronic cough was identified as one of the most common symptoms observed in postacute sequelae of SARS-CoV-2 infection (i.e., long COVID; Thaweethai et al., 2023). Even in some lung diseases such as asthma, hypertussia can develop as a syndrome resulting from structural changes to airway epithelial sensory nerves, specifically increased nerve density (Drake et al., 2021; Shapiro et al., 2021). Airway nerve remodeling leads to richer innervation and enhanced nerve sensitivity. Increased nerve activity also causes the release of neuropeptides, further intensifying widespread neuroinflammation in the airways (Barnes, 2001) that results in more frequent coughing in response to mild stimuli (Matsumoto et al., 2012). Persistent airway nerve stimulation is believed to ultimately induce peripheral and central nervous sensitization, fueling the chronic nature of cough symptoms in hypertussia (Latremoliere & Woolf, 2009; Niimi & Chung, 2015). Accumulating evidence confirms that the neural regions of patients with hypertussia differ from those without cough dysfunction (Ando et al., 2016; Arinze et al., 2023; Misono et al., 2023; Namgung et al., 2022), further supporting changes at the level of the central nervous system. Neurogenic etiologies of hypertussia presently lack an agreed-upon definition and the diagnosis varies widely (Wamkpah et al., 2022) but is generally suspected as a diagnosis of exclusion rather than a specific medical label (Altman et al., 2015; Lim, 2014).
How Do Speech-Language Pathologists Treat Cough Disorders?
Management of disordered cough requires a combination of medical, procedural, and/or behavioral approaches (Al-Biltagi et al., 2022; Wamkpah et al., 2022). Speech-language pathologists are among multiple specialists involved in treating disordered cough (ASHA, 2016; Parker et al., 2023; Song et al., 2023), specifically by delivering nonpharmacological treatments. Although the term speech therapy does not precisely reflect how cough is managed, speech therapy is the label used here to describe services provided by speech-language pathologists for pathological cough. It is our goal to refer to speech therapy to avoid confusion with other types of pharmacological therapies.
The overarching focus of speech therapy for cough disorders is founded in cognitive behavioral principles and procedures (Slovarp et al., 2021). Speech therapy involves systematically modifying respiratory and laryngeal behaviors, cognitive processing, and sensory perception previously identified during assessment as contributing factors to a patient's cough symptoms. Given the close connection between cough and higher cognitive control (Van den Bergh et al., 2012), the malleability of cough is a fundamental focus of speech therapy. In particular, speech-language pathologists frequently implement techniques to upregulate and downregulate cough by reestablishing higher order cough pathways. Due to the dissimilar nature of the two major types of cough disorders (hypotussia vs. hypertussia), speech therapy is best tailored to address the factors contributing to a patient's specific cough disruption.
Speech Therapy for Hypotussive Cough Disorders
Hypotussia has severe implications for individuals unable to safely protect the airway (Troche, Brandimore, Okun, et al., 2014). Speech therapy for hypotussia is referred to as cough rehabilitation, and it is frequently delivered to patients with neurodegenerative diseases. A major objective of cough rehabilitation is to upregulate both the sensory and motoric (sensorimotor) aspects of cough to improve airway protection deficits ultimately. Some therapeutic interventions accomplish this by incorporating skill-based training for cough effectiveness (Troche et al., 2023) and exercise-based programs of expiratory muscle strength training (Laciuga et al., 2014; Z. Wang et al., 2019). Table 1 displays these main approaches to speech therapies for hypotussive cough disorders. The specific elements comprising sensorimotor training for airway protection include increased awareness about cough sensations, verbal cueing, visual biofeedback, and cough-inducing stimuli (Borders et al., 2022). Expiratory muscle strength training involves using pressure threshold or resistive load devices that increase expiratory loads during respiratory exercises to strengthen the expiratory muscles (Laciuga et al., 2014). Along with the motor mechanics of cough, a major goal of cough rehabilitation is to upregulate the conscious awareness of airway sensations, as an intact urge to cough serves as a prompt to eject unwanted materials from the airways to protect against uncompensated aspiration (Brandimore et al., 2017).
| Hypotussive cough disorders | • Sensorimotor training for airway protection • Expiratory muscle strength training |
| Hypertussive cough disorders | • Patient education • Cough control techniques • Laryngeal hygiene • Psychoeducational counseling |
Compared to swallowing rehabilitation, there has been less appraisal of behavioral treatment paradigms for targeting sensorimotor cough function (Borders et al., 2022) and expiratory muscle strengthening for cough (Z. Wang et al., 2019). In treatment studies, objective cough airflow metrics have proven useful in assessing cough strength and overall coordination across the three motoric phases of cough production (Lowell et al., 2023). In patients with Parkinson's disease and progressive supranuclear palsy, skill-based cough training improves cough function, most often by increasing cough airflow metrics (Borders et al., 2022; Curtis et al., 2020; Sevitz et al., 2022; Troche et al., 2023). Moreover, expiratory muscle strength training has shown favorable changes in cough effectiveness among individuals with Parkinson's disease (Pitts et al., 2009), but not patients with multiple sclerosis (Chiara et al., 2006). Linking this therapeutic intervention to airway protection deficits, even improved swallow function is observed following expiratory muscle strength training in Parkinson's disease (Troche et al., 2010). Important evidence is emerging that sensory measures of cough can also be enhanced with speech therapy, as the urge to cough increases in individuals with Parkinson's disease after skill-based cough training (Troche et al., 2023) and patients poststroke following expiratory muscle strength training (Hegland et al., 2016). Beyond intervention, speech-language pathologists can use cough strength as a screening or assessment tool for individuals at risk of aspiration (Curtis & Troche, 2020; Silverman et al., 2014). Next, an illustrative example of a clinical case of hypotussia is presented. Readers are encouraged to refer to Lowell et al.'s (2023) study for additional clinical vignettes of hypotussia.
Clinical Case Scenario of Hypotussia
A 68-year-old gentleman with a 2-year history of Parkinson's disease was referred by his neurologist to a speech-language pathologist for the complaint of difficulty swallowing (symptom). Over the past 6 months, he reported increased episodes of coughing with thin liquids accompanied by the sensation of a “sharp tickle” in his throat. He noted that this sensation occurred less frequently within the past several weeks, stating that he believed it meant his swallowing was perhaps “getting better.” Instrumental assessment of his swallowing revealed dysphagia characterized by intermittent silent aspiration with thin liquids. Spirometry was performed to measure volitional cough production. An abnormally low value of expiratory phase peak flow was observed (motor cough airflow measure), which is associated with impaired airway protection in the form of penetration and aspiration (prediction of dysphagia).
Based on this comprehensive evaluation, the speech-language pathologist chose to incorporate therapies that would address both swallowing function and cough function. The decision about which cough rehabilitation approach to select was based on the observation of an occasionally absent cough in response to aspiration and the patient's report of blunted airway sensations. This aspect of the evaluation was indicative of impairment of the sensory component of his cough (reduced awareness of airway sensations). Instead of concentrating on only cough strength (expiratory muscle strengthening), the speech-language pathologist opted to target both sensory and motoric (sensorimotor) cough function using a skill-based training approach.
The patient completed six speech therapy sessions in total. A major component focused on bringing greater awareness to airway sensations, sometimes while inhaling the tussigenic agent capsaicin (cough-inducing stimulus). The other main aspect of speech therapy included repetitions of volitional cough productions with a goal of achieving a higher expiratory phase peak flow via spirometry. The patient was encouraged to reach this target as he watched the airflow signal on the computer monitor in real time while he coughed (visual biofeedback). In addition to increasing cough strength, this motoric practice improved his coordination of the three phases of inspiration, compression, and expulsion to enhance overall cough effectiveness. Verbal instructions and prompts were provided, as needed (verbal cueing). Compared to baseline cough strength, the patient's posttest expiratory phase peak flow increased and reached a value within functional limits. Subjectively, his sensory awareness of airway irritation enhanced when inhaling capsaicin. Following discharge from speech therapy, his cough strength was monitored periodically via spirometry to reassess his airway protective function and to indicate whether further instrumental swallowing assessment was warranted.
Speech Therapy for Hypertussive Cough Disorders
An algorithmic approach is used to manage hypertussive cough disorders, which is necessary to generate an accurate medical diagnosis and exclude other medically treatable etiologies of cough symptoms (Dicpinigaitis et al., 2023; Morice et al., 2020; Pratter et al., 1993). A thorough, stepwise medical workup is necessary prior to initiating speech therapy for pathological cough. Pharmacological treatments for hypertussive cough disorders include neuromodulation via peripheral nerve blocks (i.e., superior laryngeal nerve; Duffy et al., 2021; Quinton et al., 2023; Simpson et al., 2018; Talbot et al., 2023; Tipton et al., 2023) and centrally acting neuromodulating drugs (e.g., gabapentin, pregabalin; Adeli et al., 2023; Amador et al., 2023; Zhang et al., 2023). Discoveries and investigations are ongoing for other promising drug targets for hypertussia (Mazzone & McGarvey, 2021). Speech therapy, in conjunction with medical and procedural management, is an established nonpharmacological option for treating hypertussive cough disorders. Patients pursue speech therapy for hypertussia because their cough symptoms are bothersome and they want the cough problem to resolve (Rao et al., 2022). Patients can experience difficulty inhibiting cough (Cho, Fletcher, et al., 2019). As such, a primary goal of speech therapy is to downregulate the sensory and motor aspects of cough deliberately. In contrast to medical interventions, speech therapy offers nonpharmacological approaches of informing patients about the role of cough in the presence and absence of disease and instructing patients on how to manage cough symptoms optimally. Several terms describe this type of speech therapy: behavioral cough suppression therapy and cough control therapy (Vertigan et al., 2019).
As shown in Table 1, widely recognized components of speech therapy consist of educating patients, introducing techniques to regulate cough better, coaching how to reduce bothersome cough and airway symptoms through laryngeal hygiene, and incorporating psychoeducational counseling (Chamberlain et al., 2013; Gibson & Vertigan, 2009; Peng et al., 2023; Soni et al., 2017; Vertigan, Theodoros, Gibson, & Winkworth, 2007). While no standard protocol exists, specific examples of strategies implemented in the Therapy Program for Management of Chronic Cough include sensory awareness, volitional cough substitution, and generalization (Ribeiro, Lopes, & Behlau, 2021). Another common therapeutic technique for hypertussia is breath control, also known as respiratory retraining exercises (Murry et al., 2004), such as pursed-lip and relaxed-throat breathing (Vertigan, Gibson, et al., 2008). Various benign stimuli, often at low levels, elicit heightened cough symptoms in patients with hypertussia (Won et al., 2019). Examples of triggering stimuli include external mechanical pressure to the neck and thorax (Lavorini et al., 2023), internal mechanical stimulation during vocalization (Francis et al., 2016), airborne chemical inhalation (Sandage et al., 2021), posterior nasal drainage (Lim et al., 2011), and gastroesophageal reflux (Decalmer et al., 2012). The theme of triggering stimuli is embedded throughout speech therapy, including identifying salient triggers, educating about lifestyle modifications to reduce symptom exacerbation, and retraining the higher level cognitive cough pathways by practicing cough control techniques in the presence of stimuli (Hodges, 2012). In general, speech therapy for hypertussive cough disorders is beneficial because of its safety and cost-effectiveness (Mohammed et al., 2020).
Speech therapy for hypertussia has been found to improve cough-related quality of life and cough symptoms (Kapela et al., 2020; Mohammed et al., 2020; Ribeiro et al., 2022; Ryan et al., 2010; Simmons et al., 2023; Slovarp et al., 2021; Sundholm et al., 2022; Varelas et al., 2023; Vertigan et al., 2006; Wright et al., 2021). Similar interventions provided by physiotherapists improve cough outcomes in patients with hypertussia (Chamberlain Mitchell et al., 2017; Patel et al., 2011). Moreover, there are documented benefits of combining behavioral interventions with other therapies, such as nerve block injections (Gray et al., 2023), neuromodulating drugs (Vertigan et al., 2016), and cough desensitization (Slovarp et al., 2022, 2023). For further reference, a handful of systematic reviews were conducted about the effects of nonpharmacological interventions for hypertussive cough disorders (Chamberlain et al., 2014; Ilicic et al., 2022; Ribeiro, Casmerides, et al., 2021; Slinger et al., 2019). The science is incomplete to explain the changes observed following nonpharmacological interventions. Still, the central rationale is that patients relearn the higher order cognitive pathways of cough via neuroplasticity, allowing them to manage their cough symptoms better and improve their quality of life. Of note, a large portion of individuals with hypertussia also experience voice problems (Adessa et al., 2020; Everett et al., 2007; J. F. Kim et al., 2022; Martinez-Paredes et al., 2023; Sundar et al., 2021; Vertigan, Theodoros, Winkworth, & Gibson, 2007; Vertigan, Theodoros, et al., 2008a). Speech therapy protocols for hypertussia have added benefits of improving voice measures (Vertigan, Theodoros, et al., 2008b; Yang et al., 2021), particularly in an interdisciplinary approach of combined medical, procedural, and behavioral treatments (Shaha et al., 2023). To connect these concepts, a scenario is presented next describing a clinical case of hypertussia.
Clinical Case Scenario of Hypertussia
A 54-year-old nonsmoking woman with a medical history of hyperlipidemia and depression presented to her primary care physician (PCP) with a complaint of a persistent dry cough (symptom) for the past 6 months (duration). Her cough began at the time of an acute upper respiratory tract infection but never resolved (associated factor). During the PCP visit, she reported that certain activities easily elicited her cough such as laughing and wearing fitted scarves or other clothing near her neck (triggers). After experiencing an intense coughing episode that resulted in loss of consciousness (physical consequences), she stopped driving due to fear of being in a motor vehicle accident from cough syncope. Consequently, the patient reported increased social isolation and worsening depression symptoms due to her lingering cough (psychosocial impacts). History was negative for taking an angiotensin-converting enzyme inhibitor, a medication known to upregulate the cough reflex. The patient's PCP ordered a chest radiograph or X-ray (to exclude malignancy, infection, and foreign body inhalation), which was unremarkable.
To continue her medical workup to address the most common causes of cough, her PCP referred her to multiple specialists (high health care utilization) based on her cough symptoms. The patient's pulmonologist ordered spirometry that ruled out cough-variant asthma and other lung diseases. An otorhinolaryngologist found no evidence of sinonasal disease or postnasal drip. An allergist confirmed that her allergen test results were negative. Finally, a gastroenterologist diagnosed gastroesophageal reflux disease and started her on acid-suppressing therapy using proton pump inhibitors, but this did not resolve her cough. The lack of positive findings on medical tests (exclusionary testing), failing trial therapies (refractory to medical treatment), and symptom onset around the time of an acute upper respiratory infection prompted the suspicion of a postviral neurological syndrome. In conjunction with neuromodulating medication, the patient was referred for speech therapy.
Following an initial speech evaluation, the patient completed four speech therapy sessions. Given that the patient spent a long time progressing through health care resources without finding relief from her symptoms, she began to perceive that some medical providers minimized or dismissed her symptoms. At the beginning of most sessions, the speech-language pathologist validated the patient's cough experiences as being real symptoms. The speech-language pathologist confirmed that her cough was not “all in her head,” but rather was occurring “in her brain” (psychoeducational counseling). The goal of regularly incorporating this into each session was to maximize patient motivation, buy-in, and therapy adherence. Simplified descriptions followed regarding the nervous system's regulation of cough, the cough's role in protecting the body from threats, and how airway nerves can inadvertently become extra sensitive to things that now make her cough more easily or feel greater irritation in her airway (e.g., analogous to sunburn). To help connect the purpose of speech therapy in the patient's rehabilitation, emphasis was placed on the voluntary control of cough and the brain's ability to change through neuroplasticity (education). This was often a good opportunity to review the progress with her treatment goals before moving onto therapeutic interventions.
Considerable time during each session centered on strategies to retrain the cognitive pathways of the cough response. The patient was most successful in relearning to control her cough symptoms, both cough-related airway sensations and the physical act of coughing, using respiratory retraining. Specifically, pursed-lip breathing promoted an open airway and reduced the likelihood of maintaining an adducted laryngeal position that occurs during the compression phase of cough (cough control techniques). Following mastery of this breath control exercise, she gradually incorporated it with her specific cough triggers (e.g., wearing scarves) to reestablish these cough pathways. She developed better control of her cough via neuroplasticity by interrupting the previously reinforced pattern of coughing to everyday stimuli while strengthening neural connections through repeated practice of deliberately modifying her respiration. This permitted her to more readily inhibit her cough when coughing was not necessary. Given that laughing triggered her cough, she learned other voice techniques to reduce laryngeal tension and balance airflow during phonation. Finally, the speech-language pathologist helped the patient set realistic goals to modify behaviors that might exacerbate her cough symptoms. For example, she was instructed to limit substances in her diet with irritating properties, and that may worsen gastroesophageal reflux (e.g., alcohol). These behaviors were intended to prevent further sensitivity of the airway nerves (laryngeal hygiene). Following the completion of speech therapy in conjunction with neuromodulation, the patient reported substantial improvement in her chronic cough, quality of life, and depression symptoms.
What Are Future Research Directions in Cough?
Despite the critical role of cough in airway protection and the major public health implications of pathological cough, research is still developing. Therefore, there is ample justification for pursuing multiple, simultaneous, and interdisciplinary avenues of investigation in cough. Continued basic science is needed to enhance further the understanding of the complex neurobiology of cough function that has yet to be discovered in health and disease (Ando et al., 2016). In particular, efforts should focus on elucidating the specific neuronal dysregulation identified in patients with cough disorders due to identified neurological diseases (e.g., Parkinson's disease), as well as suspected but unconfirmed neurogenic etiologies (e.g., cough hypersensitivity syndrome). Whenever possible, discoveries about the pathophysiology of cough will be most helpful in improving the accuracy of clinical diagnostics and using more informed approaches with future treatments such as drug development (K. Wang et al., 2017).
Next, substantial heterogeneity exists in hypertussive cough disorders (Mazzone et al., 2018). Distinguishing patient subgroups of hypertussia deserves greater attention to tailor treatments (Chung et al., 2022; Mazzone & McGarvey, 2021), including determining which patients are good candidates for receiving speech therapy compared to pharmacological treatments. Evidence is also lacking regarding the timing of speech therapy initiation in a patient's course of treatment (Soni et al., 2017; Vertigan et al., 2019), in addition to the frequency and duration of speech therapy sessions (Chamberlain Mitchell et al., 2019). With the development of newer drug targets, research will be warranted to elucidate combined effects of speech therapy with antitussive agents to optimize clinical outcomes (Vertigan, 2023). Much like the awareness of providing swallowing rehabilitation across different age-related conditions (Humbert & Robbins, 2008), behaviorally based interventions for hypertussive cough problems may be advantageous for patients with other chronic lung diseases. Further research is warranted to tailor these nonpharmacological treatments and determine safety (Birring et al., 2017; Mohammed et al., 2020). For instance, debates are ongoing regarding the potential role of speech therapy as a holistic approach among patients with advanced lung cancer (Shin & Bush, 2022) and interstitial lung disease (Dasouki et al., 2023). Finally, a gap continues to exist regarding patient access to speech-language pathologists and other clinicians properly trained in treating cough disorders (Puente-Maestu, 2023).
Summary and Key Takeaways
This clinical focus article aimed to broaden speech-language pathologists' understanding of the multiple factors influencing cough function and complex mechanisms underlying clinical cough disorders. Cough is a life-sustaining defense that protects the airway from respiratory threats. Although cough is critical for survival, too little coughing (hypotussia) and too much coughing (hypertussia) cause devastating complications. A key distinction between these clinical categories is that hypotussia is associated with significant mortality related to airway protection deficits, while hypertussia is associated with substantial morbidity. Cough involves multiple neuronal pathways with airway afferent inputs in the periphery, central pathway processing, and higher level cortical networks. Based on the neural circuitry of cognitive processing and cough regulation, the foundation of nonpharmacological treatment in speech therapy relies on viewing cough as a modifiable respiratory act. Speech therapy offers a complementary approach to medical and procedural management for pathological cough and is supported by the current clinical evidence. Speech therapy approaches and outcome measures should be critically selected to reflect the different needs of a patient's cough rehabilitation. Particularly, it is important to distinguish goals related to upregulating cough sensation and muscle strength to reduce the risk of aspiration in hypotussive cough disorders versus goals associated with inhibiting and replacing cough with other behaviors to improve the quality of life among those with hypertussive cough disorders. Limited visibility of nonpharmacological treatment for disordered cough presents opportunities for improved outreach, awareness, and referrals for speech therapy services to reduce the length of time that patients suffer with cough symptoms. In conclusion, speech-language pathologists are actively encouraged and supported to continue adding knowledge and skills about cough and related respiratory functions to their expanding clinical repertoires.
Data Availability Statement
The information generated to write this current clinical focus article is available from the corresponding author upon reasonable request.
Acknowledgments
The authors are grateful to Ianessa Humbert for her helpful input about the content of this clinical focus article. Special thanks to Joseph Duffy, Rene Utianski, Heather Clark, and Julie Stierwalt for their clinical expertise in assessing and treating functional neurological disorders.
References
Ackah, M., Ameyaw, L., Salifu, M. G., OseiYeboah, C., Serwaa Ampomaa Agyemang, A., Acquaah, K., Koranteng, Y. B., & Opare-Appiah, A. (2022). Estimated burden, and associated factors of urinary incontinence among Sub-Saharan African women aged 15–100 years: A systematic review and meta-analysis. PLOS Global Public Health, 2(6).
Adeli, S. H., Beigi, A. M., Ahmadpour, S., Habibi, M. A., Pashaei, M. R., Sharifipour, E., Shakeri, M., & Asghari, A. (2023). Effects of pregabalin as a neural pathway inhibitor for the treatment of resistant subacute and chronic cough: A pilot clinical trials study. Reviews on Recent Clinical Trials. Advance online publication.
Adessa, M., Xiao, R., Hull, D., Bowen, A. J., Milstein, C. F., Benninger, M. S., & Bryson, P. C. (2020). Benign vocal fold lesions in patients with chronic cough. Otolaryngology—Head & Neck Surgery, 162(3), 322–325.
Al-Biltagi, M., Bediwy, A. S., & Saeed, N. K. (2022). Cough as a neurological sign: What a clinician should know. World Journal of Critical Care Medicine, 11(3), 115–128.
Altman, K. W., Noordzij, J. P., Rosen, C. A., Cohen, S., & Sulica, L. (2015). Neurogenic cough. The Laryngoscope, 125(7), 1675–1681.
Amador, R., Goebel, R., Noordzij, J. P., Bhatt, N. K., Cohen, S., Daniels, K., Tracy, L., Yajima, M., & Krisciunas, G. P. (2023). A systematic review and meta-analysis of neuromodulators to treat chronic airway hypersensitivity. American Journal of Otolaryngology, 44(3), Article 103815.
American Speech-Language-Hearing Association. (n.d.-a). Adult dysphagia [Practice portal]. http://www.asha.org/Practice-Portal/Clinical-Topics/Adult-Dysphagia/
American Speech-Language-Hearing Association. (n.d.-b). Aerodigestive disorders [Practice portal]. http://www.asha.org/Practice-Portal/Clinical-Topics/Aerodigestive-Disorders/
American Speech-Language-Hearing Association. (n.d.-c). Voice disorders [Practice portal]. http://www.asha.org/Practice-Portal/Clinical-Topics/Voice-Disorders/
American Speech-Language-Hearing Association. (2016). Scope of practice in speech-language pathology [Scope of practice]. https://www.asha.org/policy/sp2016-00343/
Amin, M. R., & Belafsky, P. C. (2010). Cough and swallowing dysfunction. Otolaryngologic Clinics of North America, 43(1), 35–42, Article viii.
Ando, A., Smallwood, D., McMahon, M., Irving, L., Mazzone, S. B., & Farrell, M. J. (2016). Neural correlates of cough hypersensitivity in humans: Evidence for central sensitisation and dysfunctional inhibitory control. Thorax, 71(4), 323–329.
Arinze, J. T., Vinke, E. J., Verhamme, K. M. C., de Ridder, M. A. J., Stricker, B., Ikram, M. K., Brusselle, G., & Vernooij, M. W. (2023). Chronic cough-related differences in brain morphometry in adults: A population-based study. Chest, 164(1), 169–178.
Barnes, P. J. (2001). Neurogenic inflammation in the airways. Respiration Physiology, 125(1–2), 145–154.
Birring, S. S., Currie, C. J., Holden, S. E., Jenkins-Jones, S., Berni, E. R., Jones, B., Berni, T. R., & Langerman, H. (2021). The financial burden of treating patients presenting with acute and chronic cough. Current Medical Research and Opinion, 37(12), 2175–2184.
Birring, S. S., Floyd, S., Reilly, C. C., & Cho, P. S. P. (2017). Physiotherapy and speech and language therapy intervention for chronic cough. Pulmonary Pharmacology & Therapeutics, 47, 84–87.
Borders, J. C., Curtis, J. A., Sevitz, J. S., Vanegas-Arroyave, N., & Troche, M. S. (2022). Immediate effects of sensorimotor training in airway protection (smTAP) on cough outcomes in progressive supranuclear palsy: A feasibility study. Dysphagia, 37(1), 74–83.
Borders, J. C., Sevitz, J. S., Curtis, J. A., Vanegas-Arroyave, N., & Troche, M. S. (2021). Sensorimotor cough dysfunction is prevalent and pervasive in progressive supranuclear palsy. Movement Disorders, 36(11), 2624–2633.
Brander, L., Moerer, O., Hedenstierna, G., Beck, J., Takala, J., Slutsky, A. S., & Sinderby, C. (2017). Neural control of ventilation prevents both over-distension and de-recruitment of experimentally injured lungs. Respiratory Physiology & Neurobiology, 237, 57–67.
Brandimore, A. E., Hegland, K. W., Okun, M. S., Davenport, P. W., & Troche, M. S. (2017). Voluntary upregulation of reflex cough is possible in healthy older adults and Parkinson's disease. Journal of Applied Physiology, 123(1), 19–26.
Bucca, C. B., Culla, B., Guida, G., Sciascia, S., Bellone, G., Moretto, A., Heffler, E., Bugiani, M., Rolla, G., & Brussino, L. (2011). Unexplained chronic cough and vitamin B-12 deficiency. American Journal of Clinical Nutrition, 93(3), 542–548.
Canning, B. J., Chang, A. B., Bolser, D. C., Smith, J. A., Mazzone, S. B., McGarvey, L., & CHEST Expert Cough Panel. (2014). Anatomy and neurophysiology of cough: CHEST guideline and expert panel report. Chest, 146(6), 1633–1648.
Chamberlain, S., Birring, S. S., & Garrod, R. (2014). Nonpharmacological interventions for refractory chronic cough patients: Systematic review. Lung, 192(1), 75–85.
Chamberlain, S., Garrod, R., & Birring, S. S. (2013). Cough suppression therapy: Does it work? Pulmonary Pharmacology & Therapeutics, 26(5), 524–527.
Chamberlain Mitchell, S. A. F., Ellis, J., Ludlow, S., Pandyan, A., & Birring, S. S. (2019). Non-pharmacological interventions for chronic cough: The past, present and future. Pulmonary Pharmacology & Therapeutics, 56, 29–38.
Chamberlain Mitchell, S. A. F., Garrod, R., Clark, L., Douiri, A., Parker, S. M., Ellis, J., Fowler, S. J., Ludlow, S., Hull, J. H., Chung, K. F., Lee, K. K., Bellas, H., Pandyan, A., & Birring, S. S. (2017). Physiotherapy, and speech and language therapy intervention for patients with refractory chronic cough: A multicentre randomised control trial. Thorax, 72(2), 129–136.
Chiara, T., Martin, A. D., Davenport, P. W., & Bolser, D. C. (2006). Expiratory muscle strength training in persons with multiple sclerosis having mild to moderate disability: Effect on maximal expiratory pressure, pulmonary function, and maximal voluntary cough. Archives of Physical Medicine and Rehabilitation, 87(4), 468–473.
Cho, P. S. P., Birring, S. S., Fletcher, H. V., & Turner, R. D. (2019). Methods of cough assessment. The Journal of Allergy and Clinical Immunology: In Practice, 7(6), 1715–1723.
Cho, P. S. P., Fletcher, H. V., Turner, R. D., Jolley, C. J., & Birring, S. S. (2019). Impaired cough suppression in chronic refractory cough. The European Respiratory Journal, 53(5), Article 1802203.
Cho, P. S. P., Shearer, J., Simpson, A., Campbell, S., Pennington, M., & Birring, S. S. (2022). Healthcare utilization and costs in chronic cough. Current Medical Research and Opinion, 38(7), 1251–1257.
Chung, K. F., McGarvey, L., & Mazzone, S. B. (2013). Chronic cough as a neuropathic disorder. The Lancet Respiratory Medicine, 1(5), 414–422.
Chung, K. F., McGarvey, L., Song, W.-J., Chang, A. B., Lai, K., Canning, B. J., Birring, S. S., Smith, J. A., & Mazzone, S. B. (2022). Cough hypersensitivity and chronic cough. Nature Reviews. Disease Primers, 8(1), Article 45.
Curtis, J. A., Dakin, A. E., & Troche, M. S. (2020). Respiratory–swallow coordination training and voluntary cough skill training: A single-subject treatment study in a person with Parkinson's disease. Journal of Speech, Language, and Hearing Research, 63(2), 472–486.
Curtis, J. A., & Troche, M. S. (2020). Handheld cough testing: A novel tool for cough assessment and dysphagia screening. Dysphagia, 35(6), 993–1000.
Dallal-York, J., Croft, K., Anderson, A., DiBiase, L., Donohue, C., Vasilopoulos, T., Shahmohammadi, A., Pelaez, A., Pipkin, M., Hegland, K. W., Machuca, T. N., & Plowman, E. K. (2023). A prospective examination of swallow and cough dysfunction after lung transplantation. Neurogastroenterology and Motility, 35(4), Article e14458.
Dasouki, S., Quach, S., Mancopes, R., Mitchell, S. C., Goldstein, R., Brooks, D., & Oliveira, A. (2023). A non-pharmacological cough therapy for people with interstitial lung diseases: A case report. Physiotherapy Canada, 75(4), 389–394.
Davenport, P. W. (2008). Urge-to-cough: What can it teach us about cough? Lung, 186(Suppl. 1), S107–S111.
Davenport, P. W. (2009). Clinical cough I: The urge-to-cough: A respiratory sensation. Handbook of Experimental Pharmacology, (187), 263–276.
Dávila, I., Puente, L., Quirce, S., Arismendi, E., Díaz-Palacios, M., Pereira-Vega, A., de Diego, A., Rodriguez-Hermosa, J. L., Cea-Calvo, L., Sánchez-Jareño, M., López-Cotarelo, P., & Domingo, C. (2023). Characteristics and management of patients with refractory or unexplained chronic cough in outpatient hospital clinics in Spain: A retrospective multicenter study. Lung, 201(3), 275–286.
Decalmer, S., Stovold, R., Houghton, L. A., Pearson, J., Ward, C., Kelsall, A., Jones, H., McGuinness, K., Woodcock, A., & Smith, J. A. (2012). Chronic cough: Relationship between microaspiration, gastroesophageal reflux, and cough frequency. Chest, 142(4), 958–964.
Deslee, G., Burgel, P. R., Escamilla, R., Chanez, P., Court-Fortune, I., Nesme-Meyer, P., Brinchault-Rabin, G., Perez, T., Jebrak, G., Caillaud, D., Paillasseur, J. L., & Roche, N. (2016). Impact of current cough on health-related quality of life in patients with COPD. International Journal of Chronic Obstructive Pulmonary Disease, 11, 2091–2097.
Dicpinigaitis, P. V. (2021). Prevalence of stress urinary incontinence in women presenting for evaluation of chronic cough. ERJ Open Research, 7(1), 00012-2021.
Dicpinigaitis, P. V., Altman, K. W., Ulger Isci, I., Ke, X., & Blaiss, M. (2023). Interdisciplinary collaboration in the diagnosis and management of chronic cough: The role and importance of primary care providers. Current Medical Research and Opinion, 39(10), 1375–1381.
Dicpinigaitis, P. V., Birring, S. S., Blaiss, M., McGarvey, L. P., Morice, A. H., Pavord, I. D., Satia, I., Smith, J. A., La Rosa, C., Li, Q., Nguyen, A. M., Schelfhout, J., Tzontcheva, A., & Muccino, D. (2022). Demographic, clinical, and patient-reported outcome data from 2 global, Phase 3 trials of chronic cough. Annals of Allergy, Asthma & Immunology, 130(1), 60–66.
Dicpinigaitis, P. V., Tso, R., & Banauch, G. (2006). Prevalence of depressive symptoms among patients with chronic cough. Chest, 130(6), 1839–1843.
Dion, G. R., Achlatis, E., Teng, S., Fang, Y., Persky, M., Branski, R. C., & Amin, M. R. (2017). Changes in peak airflow measurement during maximal cough after vocal fold augmentation in patients with glottic insufficiency. JAMA Otolaryngology—Head & Neck Surgery, 143(11), 1141–1145.
Dominguez-Ortega, J., Plaza, V., Li, V. W., Fonseca, E., Cea-Calvo, L., Martin, A., Sanchez-Jareno, M., Brady, J. E., & Schelfhout, J. (2022). Prevalence of chronic cough and patient characteristics in adults in Spain: A population-based cross-sectional survey. Chronic Respiratory Disease, 19.
Dornelas, R., Casmerides, M. C. B., da Silva, R. C., Victória Dos Anjos Souza M., Pereira, L. T., Ribeiro, V. V., & Behlau, M. (2022). Clinical parameters of the speech-language pathology assessment of the chronic cough: A scoping review. Journal of Voice. Advance online publication.
Drake, M. G., Cook, M., Fryer, A. D., Jacoby, D. B., & Scott, G. D. (2021). Airway sensory nerve plasticity in asthma and chronic cough. Frontiers in Physiology, 12, Article 720538.
Driessen, A. K., Devlin, A. C., Lundy, F. T., Martin, S. L., Sergeant, G. P., Mazzone, S. B., & McGarvey, L. P. (2020). Perspectives on neuroinflammation contributing to chronic cough. The European Respiratory Journal, 56(4), Article 2000758.
Duffy, J. R., Litts, J. K., & Fink, D. S. (2021). Superior laryngeal nerve block for treatment of neurogenic cough. The Laryngoscope, 131(10), E2676–E2680.
Everett, C. F., Kastelik, J. A., Thompson, R. H., & Morice, A. H. (2007). Chronic persistent cough in the community: A questionnaire survey. Cough, 3(1), Article 5.
Farrell, M. J., Cole, L. J., Chiapoco, D., Egan, G. F., & Mazzone, S. B. (2012). Neural correlates coding stimulus level and perception of capsaicin-evoked urge-to-cough in humans. NeuroImage, 61(4), 1324–1335.
Farrell, M. J., Koch, S., Ando, A., Cole, L. J., Egan, G. F., & Mazzone, S. B. (2014). Functionally connected brain regions in the network activated during capsaicin inhalation. Human Brain Mapping, 35(11), 5341–5355.
Farrell, M. J., & Mazzone, S. B. (2014). Sensations and regional brain responses evoked by tussive stimulation of the airways. Respiratory Physiology & Neurobiology, 204, 58–63.
Fontana, G. A. (2008). Before we get started: What is a cough? Lung, 186(Suppl. 1), S3–S6.
Fontana, G. A., & Lavorini, F. (2006). Cough motor mechanisms. Respiratory Physiology & Neurobiology, 152(3), 266–281.
Francis, D. O., Slaughter, J. C., Ates, F., Higginbotham, T., Stevens, K. L., Garrett, C. G., & Vaezi, M. F. (2016). Airway hypersensitivity, reflux, and phonation contribute to chronic cough. Clinical Gastroenterology and Hepatology, 14(3), 378–384.
Fullerton, A., Mou, Y., Silver, N., Chheda, N., Bolser, D. C., & Wheeler-Hegland, K. (2020). Impact of tussigenic stimuli on perceived upper airway sensation and motor cough response following total laryngectomy. Frontiers in Physiology, 11, Article 477.
Fullerton, A., Mou, Y., Silver, N., Chheda, N. N., Hitchcock, K., & Hegland, K. (2021). Reflex vs. volitional cough differences amongst head and neck cancer survivors characterized by time since treatment and aspiration status. Respiratory Physiology & Neurobiology, 293, Article 103702.
Gaziano, J., & Serrano, J. I. (2012). Transferable skills in the field of speech language pathology. Current Opinion in Otolaryngology & Head and Neck Surgery, 20(3), 155–159.
Gibson, P. G., & Vertigan, A. E. (2009). Speech pathology for chronic cough: A new approach. Pulmonary Pharmacology & Therapeutics, 22(2), 159–162.
Gibson, P. G., Wang, G., McGarvey, L., Vertigan, A. E., Altman, K. W., Birring, S. S., & CHEST Expert Cough Panel. (2016). Treatment of unexplained chronic cough: CHEST guideline and expert panel report. Chest, 149(1), 27–44.
Gray, A. J., Hoffman, M. R., Yang, Z. M., Vandiver, B., Purvis, J., Morgan, J. P., Hapner, E. R., Dominguez, L., Tibbetts, K., & Simpson, C. B. (2023). Indications and short-term outcomes for in-office therapeutic superior laryngeal nerve block. Annals of Otology, Rhinology, & Laryngology. Advance online publication.
Guo, L., Wu, C., Chen, C., Zhang, B., Wu, J., Xie, Y., & Gui, P. (2023). Anodal transcranial direct current stimulation over the right primary somatosensory cortex increases cough reflex sensitivity: A pilot randomised controlled crossover trial. ERJ Open Research, 9(5), 00238–02023.
Hammond, C. A. S., Goldstein, L. B., Zajac, D. J., Gray, L., Davenport, P. W., & Bolser, D. C. (2001). Assessment of aspiration risk in stroke patients with quantification of voluntary cough. Neurology, 56(4), 502–506.
Hegland, K. W., Bolser, D. C., & Davenport, P. W. (2012). Volitional control of reflex cough. Journal of Applied Physiology, 113(1), 39–46.
Hegland, K. W., Davenport, P. W., Brandimore, A. E., Singletary, F. F., & Troche, M. S. (2016). Rehabilitation of swallowing and cough functions following stroke: An expiratory muscle strength training trial. Archives of Physical Medicine and Rehabilitation, 97(8), 1345–1351.
Hegland, K. W., & Sapienza, C. (2013). SLP's role in evaluation and treatment of cough function. SIG 13 Perspectives on Swallowing and Swallowing Disorders (Dysphagia), 22(3), 85–93.
Hilton, E., Marsden, P., Thurston, A., Kennedy, S., Decalmer, S., & Smith, J. A. (2015). Clinical features of the urge-to-cough in patients with chronic cough. Respiratory Medicine, 109(6), 701–707.
Hodges, H. L. (2012). Speech therapy for the treatment of functional respiratory disorders. In R. D. Anbar (Ed.), Functional respiratory disorders (pp. 251–278). Humana Press.
Humbert, I. A., & Robbins, J. (2008). Dysphagia in the elderly. Physical Medicine and Rehabilitation Clinics of North America, 19(4), 853–866, ix–x.
Hutchings, H. A., Morris, S., Eccles, R., & Jawad, M. S. M. (1993). Voluntary suppression of cough induced by inhalation of capsaicin in healthy volunteers. Respiratory Medicine, 87(5), 379–382.
Ilicic, A. M., Oliveira, A., Habash, R., Kang, Y., Kho, M., Goldstein, R., & Brooks, D. (2022). Non-pharmacological management of non-productive chronic cough in adults: A systematic review. Frontiers in Rehabilitation Sciences, 3, Article 905257.
Irwin, R. S., Dudiki, N., French, C. L., & CHEST Expert Cough Panel. (2020). Life-threatening and non–life-threatening complications associated with coughing: A scoping review. Chest, 158(5), 2058–2073.
Janssens, T., Brepoels, S., Dupont, L., & Van den Bergh, O. (2015). The impact of harmfulness information on citric acid induced cough and urge-to-cough. Pulmonary Pharmacology & Therapeutics, 31, 9–14.
Janssens, T., Silva, M., Davenport, P. W., Van Diest, I., Dupont, L. J., & Van den Bergh, O. (2014). Attentional modulation of reflex cough. Chest, 146(1), 135–141.
Kapela, S. L., Vertigan, A. E., & Gibson, P. G. (2020). Speech pathology intervention for chronic refractory cough: A pilot study examining the benefit of using prerecorded videos as an adjunct to therapy. Journal of Voice, 34(4), 647.e7–647.e14.
Kim, J. F., Watson, W., Becerra, B. J., Crawley, B. K., Saab, R., Krishna, P., & Murry, T. (2022). The diagnosis and time of onset of voice disorders in patients with chronic cough. Journal of Voice. Advance online publication.
Kim, J. Y., Davenport, P. W., Mou, Y., & Hegland, K. (2023). Primary site of constriction during the compression phase of cough in healthy young adults. Respiratory Physiology & Neurobiology, 311, Article 104033.
Kum, E., Guyatt, G. H., Devji, T., Wang, Y., Bakaa, L., Lan, L., Liu, E., Mastrolonardo, A., Couban, R., O'Byrne, P. M., & Satia, I. (2021). Cough symptom severity in patients with refractory or unexplained chronic cough: A systematic survey and conceptual framework. European Respiratory Review, 30(161), Article 210104.
Laciuga, H., Rosenbek, J. C., Davenport, P. W., & Sapienza, C. M. (2014). Functional outcomes associated with expiratory muscle strength training: Narrative review. Journal of Rehabilitation Research and Development, 51(4), 535–546.
Lan, N. S. H., Moore, I., & Lake, F. (2021). Understanding cough in interstitial lung disease: A cross-sectional study on the adequacy of treatment. Internal Medicine Journal, 51(6), 923–929.
Landt, E., Colak, Y., Lange, P., Laursen, L. C., Nordestgaard, B. G., & Dahl, M. (2020). Chronic cough in individuals with COPD: A population-based cohort study. Chest, 157(6), 1446–1454.
Latremoliere, A., & Woolf, C. J. (2009). Central sensitization: A generator of pain hypersensitivity by central neural plasticity. The Journal of Pain, 10(9), 895–926.
Lavorini, F., Bernacchi, G., Fumagalli, C., Noale, M., Maggi, S., Mutolo, D., Cinelli, E., & Fontana, G. A. (2023). Somatically evoked cough responses help to identify patients with difficult-to-treat chronic cough: A six-month observational cohort study. EClinicalMedicine, 57, Article 101869.
Lee, K. K., Ward, K., Rafferty, G. F., Moxham, J., & Birring, S. S. (2015). The intensity of voluntary, induced, and spontaneous cough. Chest, 148(5), 1259–1267.
Lee, K. W., Kim, S. B., Lee, J. H., & Kim, S. W. (2023). Cut-off value of voluntary peak cough flow in patients with Parkinson's disease and its association with severe dysphagia: A retrospective pilot study. Medicina, 59(5),Article 921.
Lee, P. C. L., Cotterill-Jones, C., & Eccles, R. (2002). Voluntary control of cough. Pulmonary Pharmacology & Therapeutics, 15(3), 317–320.
Leech, J., Mazzone, S. B., & Farrell, M. J. (2012). The effect of placebo conditioning on capsaicin-evoked urge to cough. Chest, 142(4), 951–957.
Leech, J., Mazzone, S. B., & Farrell, M. J. (2013). Brain activity associated with placebo suppression of the urge-to-cough in humans. American Journal of Respiratory and Critical Care Medicine, 188(9), 1069–1075.
Lim, K. G. (2014). Neurogenic cough. The Journal of Allergy and Clinical Immunology, 133(6), 1779–1779.e3.
Lim, K. G., Rank, M. A., Kita, H., Patel, A., & Moore, E. (2011). Neuropeptide levels in nasal secretions from patients with and without chronic cough. Annals of Allergy, Asthma & Immunology, 107(4), 360–363.
Lowell, E. R., Borders, J. C., Sevitz, J. S., Dakin, A. E., Brates, D., & Troche, M. S. (2023). A primer on hypotussic cough: Mechanisms and assessment. Current Otorhinolaryngology Reports, 11(2), 182–191.
Madison, J. M., & Irwin, R. S. (2005). Chronic cough in adults with interstitial lung disease. Current Opinion in Pulmonary Medicine, 11(5), 412–416.
Martinez-Paredes, J. F., Alfakir, R., Thompson, C. C., Menton, S. M., & Rutt, A. (2023). Effect of chronic cough on voice measures in patients with dysphonia. Journal of Voice, 37(2), 251–256.
Matsumoto, H., Tabuena, R. P., Niimi, A., Inoue, H., Ito, I., Yamaguchi, M., Otsuka, K., Takeda, T., Oguma, T., Nakaji, H., Tajiri, T., Iwata, T., Nagasaki, T., Jinnai, M., Matsuoka, H., & Mishima, M. (2012). Cough triggers and their pathophysiology in patients with prolonged or chronic cough. Allergology International, 61(1), 123–132.
Mazzone, S. B. (2004). Sensory regulation of the cough reflex. Pulmonary Pharmacology & Therapeutics, 17(6), 361–368.
Mazzone, S. B., Chung, K. F., & McGarvey, L. (2018). The heterogeneity of chronic cough: A case for endotypes of cough hypersensitivity. The Lancet Respiratory Medicine, 6(8), 636–646.
Mazzone, S. B., Cole, L. J., Ando, A., Egan, G. F., & Farrell, M. J. (2011). Investigation of the neural control of cough and cough suppression in humans using functional brain imaging. The Journal of Neuroscience, 31(8), 2948–2958.
Mazzone, S. B., & Farrell, M. J. (2019). Heterogeneity of cough neurobiology: Clinical implications. Pulmonary Pharmacology & Therapeutics, 55, 62–66.
Mazzone, S. B., & McGarvey, L. (2021). Mechanisms and rationale for targeted therapies in refractory and unexplained chronic cough. Clinical Pharmacology and Therapeutics, 109(3), 619–636.
Mazzone, S. B., McGovern, A. E., Yang, S. K., Woo, A., Phipps, S., Ando, A., Leech, J., & Farrell, M. J. (2013). Sensorimotor circuitry involved in the higher brain control of coughing. Cough, 9(1), 7.
Mazzone, S. B., McLennan, L., McGovern, A. E., Egan, G. F., & Farrell, M. J. (2007). Representation of capsaicin-evoked urge-to-cough in the human brain using functional magnetic resonance imaging. American Journal of Respiratory and Critical Care Medicine, 176(4), 327–332.
Mazzone, S. B., & Undem, B. J. (2016). Vagal afferent innervation of the airways in health and disease. Physiological Reviews, 96(3), 975–1024.
McGarvey, L., Heaney, L. G., & MacMahon, J. (1998). A retrospective survey of diagnosis and management of patients presenting with chronic cough to a general chest clinic. International Journal of Clinical Practice, 52(3), 158–161. https://www.ncbi.nlm.nih.gov/pubmed/9684430
McGarvey, L., Morice, A. H., Martin, A., Li, V. W., Doane, M. J., Urdaneta, E., Schelfhout, J., Ding, H., & Fonseca, E. (2023). Burden of chronic cough in the U.K.: Results from the 2018 National Health and Wellness Survey. ERJ Open Research, 9(4), 00157-2023.
Meltzer, E. O., Zeiger, R. S., Dicpinigaitis, P., Bernstein, J. A., Oppenheimer, J. J., Way, N. A., Li, V. W., Boggs, R., Doane, M. J., Urdaneta, E., Weaver, J. P., Schelfhout, J., & Fonseca, E. (2021). Prevalence and burden of chronic cough in the United States. The Journal of Allergy and Clinical Immunology: In Practice, 9(11), 4037–4044.e2.
Milgrom, H., Corsello, P., Freedman, M., Blager, F. B., & Wood, R. P. (1990). Differential diagnosis and management of chronic cough. Comprehensive Therapy, 16(10), 46–53. https://www.ncbi.nlm.nih.gov/pubmed/2249400
Mir, M. J., & Hegland, K. W. (2021). A survey of speech-language pathologists' experience with clinical cough assessment. Perspectives of the ASHA Special Interest Groups, 6(6), 1627–1640.
Misono, S., Xu, J., Oh, J., Sombrio, A., Stockness, A., Mahnan, A., & Konczak, J. (2023). Atypical activation of laryngeal somatosensory-motor cortex during vocalization in people with unexplained chronic cough. JAMA Otolaryngology—Head & Neck Surgery, 149(9), 820–827.
Mohammed, S., Steer, J., Ellis, J., & Parker, S. M. (2020). Nonpharmacological cough control therapy for chronic refractory cough and cough associated with underlying lung disease. ERJ Open Research, 6(1), 00243–02019.
Morice, A. H. (2010). The cough hypersensitivity syndrome: A novel paradigm for understanding cough. Lung, 188(Suppl. 1), S87–S90.
Morice, A. H., Jakes, A. D., Faruqi, S., Birring, S. S., McGarvey, L., Canning, B., Smith, J. A., Parker, S. M., Chung, K. F., Lai, K., Pavord, I. D., van den Berg, J., Song, W-J., Millqvist, E., Farrell, M. J., Mazzone, S. B., Dicpinigaitis, P., & Chronic Cough Registry. (2014). A worldwide survey of chronic cough: A manifestation of enhanced somatosensory response. The European Respiratory Journal, 44(5), 1149–1155.
Morice, A. H., Millqvist, E., Belvisi, M. G., Bieksiene, K., Birring, S. S., Chung, K. F., Dal Negro, R. W., Dicpinigaitis, P., Kantar, A., McGarvey, L. P., Pacheco, A., Sakalauskas, R., & Smith, J. A. (2014). Expert opinion on the cough hypersensitivity syndrome in respiratory medicine. The European Respiratory Journal, 44(5), 1132–1148.
Morice, A. H., Millqvist, E., Bieksiene, K., Birring, S. S., Dicpinigaitis, P., Domingo Ribas, C., Hilton Boon, M., Kantar, A., Lai, K., McGarvey, L., Rigau, D., Satia, I., Smith, J., Song, W. J., Tonia, T., van den Berg, J. W. K., van Manen, M. J. G., & Zacharasiewicz, A. (2020). ERS guidelines on the diagnosis and treatment of chronic cough in adults and children. The European Respiratory Journal, 55(1), Article 1901136.
Murgia, V., Manti, S., Licari, A., De Filippo, M., Ciprandi, G., & Marseglia, G. L. (2020). Upper respiratory tract infection-associated acute cough and the urge to cough: New insights for clinical practice. Pediatric Allergy, Immunology and Pulmonology, 33(1), 3–11.
Murry, T., Tabaee, A., & Aviv, J. E. (2004). Respiratory retraining of refractory cough and laryngopharyngeal reflux in patients with paradoxical vocal fold movement disorder. The Laryngoscope, 114(8), 1341–1345.
Murty, G. E., Lancaster, P., & Kelly, P. J. (1991). Cough intensity in patients with a vocal cord palsy. Clinical Otolaryngology and Allied Sciences, 16(3), 248–251.
Mutolo, D. (2017). Brainstem mechanisms underlying the cough reflex and its regulation. Respiratory Physiology & Neurobiology, 243, 60–76.
Namgung, E., Song, W. J., Kim, Y. H., An, J., Cho, Y. S., & Kang, D. W. (2022). Structural and functional correlates of higher cortical brain regions in chronic refractory cough. Chest, 162(4), 851–860.
Niimi, A., & Chung, K. F. (2015). Evidence for neuropathic processes in chronic cough. Pulmonary Pharmacology & Therapeutics, 35, 100–104.
Novaleski, C. K., Doty, R. L., Nolden, A. A., Wise, P. M., Mainland, J. D., & Dalton, P. H. (2023). Examining the influence of chemosensation on laryngeal health and disorders. Journal of Voice, 37(2), 234–244.
Novaleski, C. K., Hegland, K. W., Aleksandruk, M. M., Dalton, P. H., & Mainland, J. D. (2023). Characterization of ethyl butyrate-induced cough before and after breath control techniques in healthy adults. American Journal of Speech-Language Pathology, 32(2), 675–687.
Parker, S. M., Smith, J. A., Birring, S. S., Chamberlain-Mitchell, S., Gruffydd-Jones, K., Haines, J., Hennessey, S., McGarvey, L. P., Marsden, P., Martin, M. J., Morice, A., O'Hara, J., & Thomas, M. (2023). British Thoracic Society Clinical Statement on chronic cough in adults. Thorax, 78(Suppl 6), s3–s19.
Patel, A. S., Watkin, G., Willig, B., Mutalithas, K., Bellas, H., Garrod, R., Pavord, I. D., & Birring, S. S. (2011). Improvement in health status following cough-suppression physiotherapy for patients with chronic cough. Chronic Respiratory Disease, 8(4), 253–258.
Peng, Y., Zhang, T., Yuan, L., Xu, X., & Yu, L. (2023). Management of non-pharmacologic therapy for chronic refractory cough: Mechanism, composition, applicable population, and assessment. Heliyon, 9(10), Article e20351.
Perry, S. E., & Troche, M. S. (2019). Dual tasking influences cough sensorimotor outcomes in healthy young adults. Journal of Speech, Language, and Hearing Research, 62(9), 3596–3606.
Pitts, T. (2014). Airway protective mechanisms. Lung, 192(1), 27–31.
Pitts, T., Bolser, D., Rosenbek, J., Troche, M., Okun, M. S., & Sapienza, C. (2009). Impact of expiratory muscle strength training on voluntary cough and swallow function in Parkinson disease. Chest, 135(5), 1301–1308.
Pitts, T., Bolser, D., Rosenbek, J., Troche, M., & Sapienza, C. (2008). Voluntary cough production and swallow dysfunction in Parkinson's disease. Dysphagia, 23(3), 297–301.
Pitts, T., Bordelon, R., Huff, A., Byrne, B. J., & Smith, B. K. (2019). Cough effectiveness and pulmonary hygiene practices in patients with Pompe disease. Lung, 197(1), 1–8.
Pitts, T., Rose, M. J., Mortensen, A. N., Poliacek, I., Sapienza, C. M., Lindsey, B. G., Morris, K. F., Davenport, P. W., & Bolser, D. C. (2013). Coordination of cough and swallow: A meta-behavioral response to aspiration. Respiratory Physiology & Neurobiology, 189(3), 543–551.
Pitts, T., Troche, M., Mann, G., Rosenbek, J., Okun, M. S., & Sapienza, C. (2010). Using voluntary cough to detect penetration and aspiration during oropharyngeal swallowing in patients with Parkinson disease. Chest, 138(6), 1426–1431.
Pratter, M. R., Bartter, T., Akers, S., & DuBois, J. (1993). An algorithmic approach to chronic cough. Annals of Internal Medicine, 119(10), 977–983.
Puente-Maestu, L. (2023). The scourge of chronic cough. Pulmonology. Advance online publication.
Quinton, B. A., Tierney, W. S., Benninger, M. S., Nelson, R. C., Gau, V. L., Hrelec, C. M., & Bryson, P. C. (2023). The role of bilateral superior laryngeal nerve block in managing refractory chronic cough. The Laryngoscope. Advance online publication.
Rameau, A., Andreadis, K., German, A., Lachs, M. S., Rosen, T. E., Pitzrick, M. S., Symes, L. B., & Klinck, H. (2023). Changes in cough airflow and acoustics after injection laryngoplasty. The Laryngoscope, 133(10), S1–S14.
Rao, S. J., Ruckart, K. W., Nosow, L. M., Morris, A. K., Carter Wright, S., Jr., & Madden, L. L. (2022). Chronic cough: Evaluation of patients' motivation to undergo cough suppression therapy. Journal of Voice. Advance online publication.
Ribeiro, V. V., Casmerides, M. C. B., da Silva Reis, Z. M. C., de Santana Í. V., do Carmo, R. D., & Behlau, M. (2021). Efficacy of speech-language pathology therapy in chronic cough: Systematic review with meta-analysis. Journal of Voice. Advance online publication.
Ribeiro, V. V., Lopes, L. W., & Behlau, M. (2021). Presentation of the therapy program for management of chronic cough (Apresentacao do programa de terapia para manejo da tosse cronica). CoDAS, 33(3), e20200057.
Ribeiro, V. V., Lopes, L. W., de Medeiros, C. M. A., da Silva, A. C. F., de Medeiros Neto, A. H., & Behlau, M. (2022). Effectiveness of the therapy program for management of chronic cough: Preliminary data from a randomized clinical trial. American Journal of Speech-Language Pathology, 31(4), 1611–1620.
Ruddy, B. H., Pitts, T. E., Lehman, J., Spector, B., Lewis, V., & Sapienza, C. M. (2014). Improved voluntary cough immediately following office-based vocal fold medialization injections. The Laryngoscope, 124(7), 1645–1647.
Ryan, N. M., Vertigan, A. E., Bone, S., & Gibson, P. G. (2010). Cough reflex sensitivity improves with speech language pathology management of refractory chronic cough. Cough, 6(1), Article 5.
Saari, E., Mononen, M., Hasala, H., Lätti, A., Kaulamo, J., Nurmi, H., Kaarteenaho, R., Purokivi, M., & Koskela, H. O. (2023). Characteristics of idiopathic pulmonary fibrosis-associated cough. A case–control study. BMC Pulmonary Medicine, 23(1), 179.
Sandage, M. J., Ostwalt, E. S., Allison, L. H., Cutchin, G. M., Morton, M. E., & Odom, S. C. (2021). Irritant-induced chronic cough triggers: A scoping review and clinical checklist. American Journal of Speech-Language Pathology, 30(3), 1261–1291.
Satia, I., Mayhew, A. J., Sohel, N., Kurmi, O., Killian, K. J., O'Byrne, P. M., & Raina, P. (2022). Impact of mental health and personality traits on the incidence of chronic cough in the Canadian Longitudinal Study on Aging. ERJ Open Research, 8(2), 00119-2022.
Schattner, A. (2020). The wide-ranging spectrum of cough-induced complications and patient harm. The American Journal of Medicine, 133(5), 544–551.
Sevitz, J. S., Borders, J. C., Dakin, A. E., Kiefer, B. R., Alcalay, R. N., Kuo, S. H., & Troche, M. S. (2022). Rehabilitation of airway protection in individuals with movement disorders: A telehealth feasibility study. American Journal of Speech-Language Pathology, 31(6), 2741–2758.
Shaha, M., Hoffman, M. R., Hapner, E. R., & Simpson, C. B. (2023). Membranous vocal fold lesions in patients with chronic cough: A case series. Journal of Voice. Advance online publication.
Shapiro, C. O., Proskocil, B. J., Oppegard, L. J., Blum, E. D., Kappel, N. L., Chang, C. H., Fryer, A. D., Jacoby, D. B., Costello, R. W., & Drake, M. G. (2021). Airway sensory nerve density is increased in chronic cough. American Journal of Respiratory and Critical Care Medicine, 203(3), 348–355.
Shin, J., & Bush, N. J. (2022). Integration of behavioral cough suppression therapy into lung cancer care: Nonpharmacologic interventions for chronic cough. Clinical Journal of Oncology Nursing, 26(1), 40–47.
Silverman, E. P., Carnaby, G., Singletary, F., Hoffman-Ruddy, B., Yeager, J., & Sapienza, C. (2016). Measurement of voluntary cough production and airway protection in Parkinson disease. Archives of Physical Medicine and Rehabilitation, 97(3), 413–420.
Silverman, E. P., Carnaby-Mann, G., Pitts, T., Davenport, P., Okun, M. S., & Sapienza, C. (2014). Concordance and discriminatory power of cough measurement devices for individuals with Parkinson disease. Chest, 145(5), 1089–1096.
Silverman, E. P., Sapienza, C. M., Miller, S., Carnaby, G., Levy, C., Tsai, H. W., & Davenport, P. W. (2016). Preliminary evidence of reduced urge to cough and cough response in four individuals following remote traumatic brain injury with tracheostomy. Canadian Respiratory Journal, 2016, Article 6875210.
Simmons, E., Kim, J. F., DeChance, D., Becerra, B. J., Crawley, B., Krishna, P., & Murry, T. (2023). Chronic refractory cough: Long-term outcomes following cough suppression therapy. Journal of Voice. Advance online publication.
Simonyan, K., Saad, Z. S., Loucks, T. M. J., Poletto, C. J., & Ludlow, C. L. (2007). Functional neuroanatomy of human voluntary cough and sniff production. NeuroImage, 37(2), 401–409.
Simpson, C. B., & Amin, M. R. (2006). Chronic cough: State-of-the-art review. Otolaryngology—Head & Neck Surgery, 134(4), 693–700.
Simpson, C. B., Tibbetts, K. M., Loochtan, M. J., & Dominguez, L. M. (2018). Treatment of chronic neurogenic cough with in-office superior laryngeal nerve block. The Laryngoscope, 128(8), 1898–1903.
Slinger, C., Mehdi, S. B., Milan, S. J., Dodd, S., Matthews, J., Vyas, A., & Marsden, P. A. (2019). Speech and language therapy for management of chronic cough. The Cochrane Database of Systematic Reviews, 7(7), Article CD013067.
Slovarp, L. J., Jette, M. E., Gillespie, A. I., Reynolds, J. E., & Barkmeier-Kraemer, J. M. (2021). Evaluation and management outcomes and burdens in patients with refractory chronic cough referred for behavioral cough suppression therapy. Lung, 199(3), 263–271.
Slovarp, L. J., Reynolds, J. E., Bozarth-Dailey, E., Popp, S., Campbell, S., & Morkrid, P. (2022). Cough desensitization treatment: A randomized, sham-controlled pilot trial for patients with refractory chronic cough. Respiratory Medicine, 193, Article 106739.
Slovarp, L. J., Reynolds, J. E., Tolbert, S., Campbell, S., Welby, S., & Morkrid, P. (2023). Cough desensitization treatment for patients with refractory chronic cough: Results of a second pilot randomized control trial. BMC Pulmonary Medicine, 23(1), Article 148.
Song, W. J., Dupont, L., Birring, S. S., Chung, K. F., Dąbrowska, M., Dicpinigaitis, P., Ribas, C. D., Fontana, G., Gibson, P. G., Guilleminault, L., Hull, J. H., Idzko, M., Kardos, P., Kim, H. J., Lai, K., Lavorini, F., Millqvist, E., Morice, A. H., Niimi, A., … McGarvey, L. P. (2023). Consensus goals and standards for specialist cough clinics: The NEUROCOUGH international Delphi study. ERJ Open Research, 9(6).
Soni, R. S., Ebersole, B., & Jamal, N. (2017). Treatment of chronic cough: Single‐institution experience utilizing behavioral therapy. Otolaryngology—Head & Neck Surgery, 156(1), 103–108.
Spinou, A. (2018). Non-pharmacological techniques for the extremes of the cough spectrum. Respiratory Physiology & Neurobiology, 257, 5–11.
Sundar, K. M., Stark, A. C., Hu, N., & Barkmeier-Kraemer, J. (2021). Is laryngeal hypersensitivity the basis of unexplained or refractory chronic cough? ERJ Open Research, 7(1), 00793-2020.
Sundholm, N., Shelly, S., Wright, M. L., Reynolds, J., Slovarp, L., & Gillespie, A. I. (2022). Effect of behavioral cough suppression therapy delivered via telehealth. Journal of Voice. Advance online publication.
Talbot, N., Heller, M., Nyirjesy, S., Kim, B., DeSilva, B., & Matrka, L. (2023). Superior laryngeal nerve block response rates in 54 neurogenic cough patients. The Laryngoscope, 133(10), 2647–2653.
Thaweethai, T., Jolley, S. E., Karlson, E. W., Levitan, E. B., Levy, B., McComsey, G. A., McCorkell, L., Nadkarni, G. N., Parthasarathy, S., Singh, U., Walker, T. A., Selvaggi, C. A., Shinnick, D. J., Schulte, C. C. M., Atchley-Challenner, R., Alba, G. A., Alicic, R., Altman, N., Anglin, K., … Foulkes, A. S. (2023). Development of a definition of postacute sequelae of SARS-CoV-2 infection. JAMA, 329(22), 1934–1946.
Tipton, C. B., Walters, R., Gudipudi, R., Smyre, D., Nguyen, S., & O'Rourke, A. K. (2023). The efficacy of superior laryngeal nerve block for neurogenic cough: A placebo-controlled trial. The Laryngoscope, 133(11), 3068–3074.
Troche, M. S., Brandimore, A. E., Godoy, J., & Hegland, K. W. (2014). A framework for understanding shared substrates of airway protection. Journal of Applied Oral Science, 22(4), 251–260.
Troche, M. S., Brandimore, A. E., Okun, M. S., Davenport, P. W., & Hegland, K. W. (2014). Decreased cough sensitivity and aspiration in Parkinson disease. Chest, 146(5), 1294–1299.
Troche, M. S., Curtis, J. A., Sevitz, J. S., Dakin, A. E., Perry, S. E., Borders, J. C., Grande, A. A., Mou, Y., Vanegas-Arroyave, N., & Hegland, K. W. (2023). Rehabilitating cough dysfunction in Parkinson's disease: A randomized controlled trial. Movement Disorders, 38(2), 201–211.
Troche, M. S., Okun, M. S., Rosenbek, J. C., Musson, N., Fernandez, H. H., Rodriguez, R., Romrell, J., Pitts, T., Wheeler-Hegland, K. M., & Sapienza, C. M. (2010). Aspiration and swallowing in Parkinson disease and rehabilitation with EMST: A randomized trial. Neurology, 75(21), 1912–1919.
Troche, M. S., Schumann, B., Brandimore, A. E., Okun, M. S., & Hegland, K. W. (2016). Reflex cough and disease duration as predictors of swallowing dysfunction in Parkinson's disease. Dysphagia, 31(6), 757–764.
Turner, R. D., & Birring, S. S. (2023). Measuring cough: What really matters? Journal of Thoracic Disease, 15(4), 2288–2299.
Undem, B. J., Zaccone, E., McGarvey, L., & Mazzone, S. B. (2015). Neural dysfunction following respiratory viral infection as a cause of chronic cough hypersensitivity. Pulmonary Pharmacology & Therapeutics, 33, 52–56.
Van den Bergh, O., Van Diest, I., Dupont, L., & Davenport, P. W. (2012). On the psychology of cough. Lung, 190(1), 55–61.
Varelas, E. A., Hwang, C., Brown, S., Chang, J., Sataluri, M., Kirke, D., Courey, M., & Goldberg, L. (2023). Standardized behavioral treatment improves chronic cough. Journal of Voice. Advance online publication.
Vertigan, A. E. (2023). State of the art for refractory cough: Multidisciplinary approach. Tuberculosis and Respiratory Diseases, 86(4), 264–271.
Vertigan, A. E., & Gibson, P. G. (2011). Urge to cough and its application to the behavioural treatment of cough. Bratislavské Lekárske Listy, 112(3), 102–108. https://www.ncbi.nlm.nih.gov/pubmed/21452759
Vertigan, A. E., & Gibson, P. G. (2012). The role of speech pathology in the management of patients with chronic refractory cough. Lung, 190(1), 35–40.
Vertigan, A. E., Gibson, P. G., Theodoros, D. G., & Winkworth, A. L. (2008). The role of sensory dysfunction in the development of voice disorders, chronic cough and paradoxical vocal fold movement. International Journal of Speech-Language Pathology, 10(4), 231–244.
Vertigan, A. E., Haines, J., & Slovarp, L. (2019). An update on speech pathology management of chronic refractory cough. The Journal of Allergy and Clinical Immunology. In Practice, 7(6), 1756–1761.
Vertigan, A. E., Kapela, S. L., Ryan, N. M., Birring, S. S., McElduff, P., & Gibson, P. G. (2016). Pregabalin and speech pathology combination therapy for refractory chronic cough: A randomized controlled trial. Chest, 149(3), 639–648.
Vertigan, A. E., Theodoros, D. G., Gibson, P. G., & Winkworth, A. L. (2006). Efficacy of speech pathology management for chronic cough: A randomised placebo controlled trial of treatment efficacy. Thorax, 61(12), 1065–1069.
Vertigan, A. E., Theodoros, D. G., Gibson, P. G., & Winkworth, A. L. (2007). Review series: Chronic cough: Behaviour modification therapies for chronic cough. Chronic Respiratory Disease, 4(2), 89–97.
Vertigan, A. E., Theodoros, D. G., Winkworth, A. L., & Gibson, P. G. (2007). Perceptual voice characteristics in chronic cough and paradoxical vocal fold movement. Folia Phoniatrica et Logopaedica, 59(5), 256–267.
Vertigan, A. E., Theodoros, D. G., Winkworth, A. L., & Gibson, P. G. (2008a). Acoustic and electroglottographic voice characteristics in chronic cough and paradoxical vocal fold movement. Folia Phoniatrica et Logopaedica, 60(4), 210–216.
Vertigan, A. E., Theodoros, D. G., Winkworth, A. L., & Gibson, P. G. (2008b). A comparison of two approaches to the treatment of chronic cough: Perceptual, acoustic, and electroglottographic outcomes. Journal of Voice, 22(5), 581–589.
Visca, D., Beghe, B., Fabbri, L. M., Papi, A., & Spanevello, A. (2020). Management of chronic refractory cough in adults. European Journal of Internal Medicine, 81, 15–21.
Wamkpah, N. S., Peterson, A. M., Lee, J. J., Jia, L., Hardi, A., Stoll, C., & Huston, M. (2022). Curbing the cough: Multimodal treatments for neurogenic cough: A systematic review and meta‐analysis. The Laryngoscope, 132(1), 107–123.
Wang, K., Milojevic, N., Sheinman, B., & Usmani, O. S. (2017). Cough management in primary, secondary and tertiary settings. Pulmonary Pharmacology & Therapeutics, 47, 93–98.
Wang, Z., Wang, Z., Fang, Q., Li, H., Zhang, L., & Liu, X. (2019). Effect of expiratory muscle strength training on swallowing and cough functions in patients with neurological diseases: A meta-analysis. American Journal of Physical Medicine & Rehabilitation, 98(12), 1060–1066.
Watts, S. A., Tabor, L., & Plowman, E. K. (2016). To cough or not to cough? Examining the potential utility of cough testing in the clinical evaluation of swallowing. Current Physical Medicine and Rehabilitation Reports, 4(4), 262–276.
Widdicombe, J., & Fontana, G. (2006). Cough: What's in a name? The European Respiratory Journal, 28(1), 10–15.
Won, H. K., Kang, S. Y., Kang, Y., An, J., Lee, J. H., Lee, S. M., Kwon, J. W., Kim, M. H., Jo, E. J., Lee, S. E., Kim, S. H., Kim, S. H., Chang, Y. S., Kim, S. H., Lee, B. J., Cho, S. H., Birring, S. S., & Song, W. J. (2019). Cough-related laryngeal sensations and triggers in adults with chronic cough: Symptom profile and impact. Allergy, Asthma & Immunology Research, 11(5), 622–631.
Won, H. K., Yoon, S. J., & Song, W. J. (2018). The double-sidedness of cough in the elderly. Respiratory Physiology & Neurobiology, 257, 65–69.
Wright, M. L., Sundar, K. M., Herrick, J. S., & Barkmeier-Kraemer, J. M. (2021). Long-term treatment outcomes after behavioral speech therapy for chronic refractory cough. Lung, 199(5), 517–525.
Yang, J., Crawley, B., Dehom, S., Krishna, P., & Murry, T. (2021). Chronic refractory cough: Objective improvement with aerodynamic-focused. Journal of Voice, 35(2), 324.e9–324.e13.
Young, E. C., Brammer, C., Owen, E., Brown, N., Lowe, J., Johnson, C., Calam, R., Jones, S., Woodcock, A., & Smith, J. A. (2009). The effect of mindfulness meditation on cough reflex sensitivity. Thorax, 64(11), 993–998.
Zaccone, E. J., & Undem, B. J. (2016). Airway vagal neuroplasticity associated with respiratory viral infections. Lung, 194(1), 25–29.
Zeiger, R. S., Schatz, M., Butler, R. K., Weaver, J. P., Bali, V., & Chen, W. (2020). Burden of specialist-diagnosed chronic cough in adults. The Journal of Allergy and Clinical Immunology. In Practice, 8(5), 1645–1657.e7.
Zhang, M., Morice, A. H., Si, F., Zhang, L., Chen, Q., Wang, S., Zhu, Y., Xu, X., Yu, L., & Qiu, Z. (2023). Antitussive efficacy of the current treatment protocol for refractory chronic cough: Our real-world experience in a retrospective cohort study. Therapeutic Advances in Respiratory Disease, 17.
Zhang, M., Sykes, D. L., Brindle, K., Sadofsky, L. R., & Morice, A. H. (2022). Chronic cough—The limitation and advances in assessment techniques. Journal of Thoracic Disease, 14(12), 5097–5119.
Zhou, J., Yi, F., Wu, F., Xu, P., Chen, M., Shen, H., Lin, L., Zhang, Y., Li, S., Wu, C., Yuan, Y., Wang, G., Ye, X., Zhang, P., Tang, H., Ma, Q., Huang, L., Qiu, Z., Deng, H., … Lai, K. (2022). Characteristics of different asthma phenotypes associated with cough: A prospective, multicenter survey in China. Respiratory Research, 23(1), Article 243.
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- Received: Aug 21, 2023
- Revised: Oct 19, 2023
- Accepted: Nov 13, 2023
- Published online: Dec 20, 2023
- Published in issue: Feb 8, 2024
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Citing Literature
- Woo-Jung Song, Deepti Vellaichamy Manian, Yeonhee Kim, Mengru Zhang, Alyn H. Morice, Cough Reflex Hypersensitivity as a Key Treatable Trait, The Journal of Allergy and Clinical Immunology: In Practice, 10.1016/j.jaip.2024.10.046, 13, 3, (469-478), (2025).
- Stephanie Misono, Carolyn K. Novaleski, Current opinion in refractory and/or unexplained chronic cough, Current Opinion in Otolaryngology & Head & Neck Surgery, 10.1097/MOO.0000000000001009, 32, 6, (403-409), (2024).
- Justine Dallal-York, Michelle S. Troche, Hypotussic cough in persons with dysphagia: biobehavioral interventions and pathways to clinical implementation, Frontiers in Rehabilitation Sciences, 10.3389/fresc.2024.1394110, 5, (2024).
