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Article Excerpt
There is emerging evidence for the efficacy of speech pathology intervention for individuals with chronic cough (CC) that persists despite medical treatment, but there are limited resources available to assist speech-language pathologists to manage this perplexing condition. The purpose of this article is to outline a treatment approach for speech pathology management of CC. The article provides an overview of medical treatment for CC, a profile of patients with CC including the association with paradoxical vocal fold movement, voice problems, and psychological issues. A protocol for management of this condition including evaluation, treatment, patient education, and the importance of motivation and compliance are provided. This article provides a practical orientation for clinicians who are less experienced in managing individuals with CC.
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Chronic cough (CC) is defined as a cough persisting for longer than 8 weeks (Pratter, Brightling, Boulet, & Irwin, 2006). Although there are multiple etiologies for CC and complexities surrounding its management, the majority of individuals with CC respond to medical management. There is emerging evidence to support the effectiveness of speech pathology treatment for CC that persists despite medical management (Blager, 2000; Gay, Blager, Bartsch, & Emery, 1987; Murry, Tabaee, & Aviv, 2004; Russell, 1991; Vertigan, 2001). Individuals with CC are generally not referred to speech pathologists until their cough is judged to be refractory to medical treatment and therefore represent a skewed proportion of the total population with CC. The theoretical basis and efficacy of speech pathology intervention for CC have been reported in previous studies (Vertigan, Theodoros, Gibson, & Winkworth, 2006a, 2006b). There is however a need for resources that outline treatment protocols to assist speech pathologists in their management of individuals with CC. The objectives of this article is to provide an overview of medical management of CC, describe the typical profile of adults with CC, and outline a protocol for assessment and management of adults with CC from the speech pathologist's perspective.
DEFINITION AND TERMINOLOGY
Cough can be classified as either acute or chronic. Chronic cough can be subdivided into cough that responds to medical treatment and cough that is refractory to medical treatment. Chronic cough can be refractory to medical treatment in up to 20% of cases (Ing & Breslin, 1997; Kardos, 2000; Lawler, 1998; Marchesani, Cecarini, Pela, & Sanguinetti, 1998), and a number of labels such as psychogenic habit cough (Gay et al., 1987), idiopathic cough (McGarvey, 2005), psychogenic cough (Pierce & Watson, 1998), habit cough (Blager, Gay, & Wood, 1988), and refractory cough (Murry et al., 2004) have been used to describe this condition. This range of terms may reflect the underlying beliefs in the etiology of persisting cough. In this article the term CC will be used to describe cough that persists despite medical management.
MEDICAL MANAGEMENT OF CHRONIC COUGH
Medical management of CC involves measuring the severity of the condition and determining the underlying cause (Chung, 2003b). The most common causes of CC are smoking, lung pathology, medications such as angiotensin converting enzyme (ACE) inhibitors, asthma, postnasal drip syndrome, and gastroesophageal reflux (GER) disease. Within the field of respiratory medicine, CC is managed according to the anatomic diagnostic protocol (ADP) (Irwin et al., 1998). This protocol encompasses a systematic approach to identifying and treating the suspected underlying etiology or etiologies of the cough through specific diagnostic testing and empiric treatment trials.
The ADP commences with the history and physical examination. If the history identifies the use of medications such as ACE inhibitors then alternative medications may be used. A chest radiograph and spirometry are then performed. If no primary pulmonary pathology is identified then diagnostic testing or empiric therapy for postnasal drip syndrome, asthma, and GER are instigated. If the cough resolves following treatment for any of these conditions then these factors are presumed to have been the cause of the cough. Speech pathologists rarely become involved in the management of patients whose cough is successfully managed according to this process.
A number of causes have been proposed for cough that persists despite medical treatment based on the ADP, and they are listed in Table 1. Speech pathology management is not widely recognized as a treatment option for CC that does not respond to medical management, and current literature in the field of respiratory medicine has not embraced speech pathology intervention as a potential management option.
DESCRIPTION AND CHARACTERISTICS OF CHRONIC COUGH
The nature of CC that persists despite medical management has received limited research attention. The duration of the CC can range from months to over 20 years (Haque, Usmani, & Barnes, 2005), and patients may be frustrated at the ineffectiveness of previous medical treatment. The typical presentation is a dry irritated cough that is triggered from the throat and occurs in bouts throughout the day; however, there is variation in the description and pattern of the cough (Vertigan, Theodoros, Gibson, & Winkworth, 2007). The specific characteristics of the cough appear to have limited diagnostic value (Mello, Irwin, & Curley, 1996; Smith, Ashurst, Jack, Woodcock, & Earis, 2006).
The majority of individuals with CC perceive little warning before their cough episodes, although some report that they cough deliberately in response to laryngeal sensations (Vertigan et al., 2007). Many patients with CC can identify triggers to their cough while others are unable to identify any triggers. Cough triggers may be classified as inhaled (e.g., smoke and fumes), temperature (including cold air or humidity), intrinsic (e.g., a sensation in the throat or anxiety), or activity (such as talking or physical exercise) (Vertigan et al., 2007). The majority of patients with CC perceive that they are unable to control their cough. Although they may have previously attempted strategies to control their cough, many feel these strategies are ineffective. Approximately 50% of individuals with CC habitually mouth breathe, which can have a drying effect on the larynx and potentially contribute to laryngeal irritation and trigger further coughing (Vertigan et al., 2007).
Paradoxical Vocal Fold Movement
Chronic Cough can be associated with paradoxical vocal fold movement (PVFM). These conditions have traditionally been considered separate entities; however, there is emerging evidence for an underlying relationship between them due to the similarities in associated medical conditions, voice symptoms and psychological issues (Altman et al., 2002; Andrianopoulos, Gallivan, & Gallivan, 2000; Morrison, Rammage, & Emami, 1999; Vertigan et al., 2006a). Milgrom, Corsello, Freedman, Blager, and Wood (1990) found that approximately 50% of individuals with CC demonstrated an abnormal pattern of vocal fold movement during respiration, which is similar to the characteristic pattern of PVFM. This pattern involves involuntary vocal fold adduction during inspiration (Milgrom et al., 1990), attenuation of the inspiratory flow volume curve, and a perception of breathing difficulty (Brugman & Newman, 1993). Similarly, Ryan and Gibson (2006) and Vertigan (2007) found that approximately half the participants with CC had evidence of PVFM following hypertonic saline challenge. Blager (2000) hypothesized that cough is a protective mechanism that relieves glottal constriction that occurs during PVFM episodes. This evidence suggests that a potential for coexisting PVFM could be considered in individuals presenting with CC and that further investigation using fiberoptic nasendoscopy or spirometry with provocation testing would help delineate whether the CC was occurring in isolation or in combination with PVFM.
Voice Disorders
Individuals with CC might present with coexisting voice problems, although there is debate regarding the significance of voice problems in this population. Vertigan, Theodoros, Winkworth, and Gibson (in press-b) reported clinically significant ratings of impaired vocal quality in 40% of individuals with CC, whereas Sandage and Schroth (2005) reported that voice problems were a less significant issue in this population. In most cases, voice problems are thought to be a result of the CC as the voice improves following behavioral management of the cough (Vertigan, Theodoros, Winkworth, & Gibson, in press-a). It is suggested that CC and voice disorders such as muscle tension dysphonia are separate conditions despite similarity in factors associated with their pathogenesis such as GER, upper respiratory tract infection, psychological processes, and extrathoracic airway hyperresponsiveness.
Research regarding triggers to the cough provides further insight into vocal function in individuals with CC. Talking is one of the most frequently identified triggers in individuals with CC (Vertigan et al., 2007). Morice et al. (Morice et al., 2004) suggested that talking and laughing might decrease lower esophageal sphincter tone and subsequently lead to coughing. It has been hypothesized that vocal fold adduction during phonation stimulates pressure receptors in...
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