Swallowing evaluation

The evaluation of swallowing disorders currently uses a variety of methods. The most common dichotomy is between instrumental and noninstrumental or clinical examinations. Although the specific goals and methods of assessment for dysphagic patients may vary among cases, the most important function of assessment is to understand the physiologic nature of the patient’s swallow in relation to the patient’s medical history. This understanding is critical for selecting appropriate treatment strategies. The clinical bedside assessment often is considered the mainstay of dysphagia management. As the first line of assessment, it frequently defines the process and requisites of the task. This article reviews the available methods of noninstrumental bedside swallowing assessment and considers the issues surrounding the use of these approaches today.

Noninstrumental clinical assessment: definition and objectives

Swallowing assessment may be defined as an organized, goal-directed evaluation of a variety of interrelated and integrated components of the deglutitive process. It is important to specify the goal of a swallowing assessment to evaluate fully the procedure employed. There are three general possibilities. First, a swallowing evaluation may form part of a medical diagnosis when the practitioner is attempting to determine the underlying pathology. Second, the swallowing evaluation may be conducted to determine the patient’s abilities and impairments and the degree to which these impairments can be modified. Third, a clinician may perform a swallowing assessment for a combination of the previous two goals . A swallowing assessment is intended to ascertain the factors related to swallowing function but need not, in itself, be diagnostic of the underlying disease. The information gathered, however, may direct further diagnostic instrumental investigations such as videofluoroscopy, nasendoscopy, manometry, and scintigraphy.

In general, any assessment protocol should reflect an underlying explanatory theory of the relationship between the pathologic mechanisms involved in the disorder. It should not be simply an observational structure used to record behavioral data. Working from a sound theoretic framework can offer direction for diagnosis and therapeutic intervention, further enhancing insights into the swallowing neurophysiology. Although the specific goals and methods of assessment in dysphagic patients may vary among cases, the most important function of an assessment is to enable the clinician to understand the physiologic nature of the patient’s swallow in relation to the patient’s medical history and thereby select appropriate treatment strategies.

Noninstrumental clinical assessment: definition and objectives

Swallowing assessment may be defined as an organized, goal-directed evaluation of a variety of interrelated and integrated components of the deglutitive process. It is important to specify the goal of a swallowing assessment to evaluate fully the procedure employed. There are three general possibilities. First, a swallowing evaluation may form part of a medical diagnosis when the practitioner is attempting to determine the underlying pathology. Second, the swallowing evaluation may be conducted to determine the patient’s abilities and impairments and the degree to which these impairments can be modified. Third, a clinician may perform a swallowing assessment for a combination of the previous two goals . A swallowing assessment is intended to ascertain the factors related to swallowing function but need not, in itself, be diagnostic of the underlying disease. The information gathered, however, may direct further diagnostic instrumental investigations such as videofluoroscopy, nasendoscopy, manometry, and scintigraphy.

In general, any assessment protocol should reflect an underlying explanatory theory of the relationship between the pathologic mechanisms involved in the disorder. It should not be simply an observational structure used to record behavioral data. Working from a sound theoretic framework can offer direction for diagnosis and therapeutic intervention, further enhancing insights into the swallowing neurophysiology. Although the specific goals and methods of assessment in dysphagic patients may vary among cases, the most important function of an assessment is to enable the clinician to understand the physiologic nature of the patient’s swallow in relation to the patient’s medical history and thereby select appropriate treatment strategies.

The clinical bedside swallowing assessment

Clinical assessment, or “clinical bedside assessment,” as it often is termed, usually includes a history of the patient’s swallowing problem, a detailed evaluation of oral, pharyngeal, and laryngeal anatomy, sensory and motor function, behavioral, cognitive, and language abilities, and a trial feeding (if deemed appropriate). Crucial information can be gathered during history taking, such as onset, duration, frequency, and description of swallowing problems. In this early stage, initial hypotheses are formed regarding the location of the problem within the swallowing system. Clinical symptoms such as localization are not always accurate, however. For instance, patients who localize their symptoms to the level of the proximal esophagus frequently are inaccurate; accuracy increases when symptoms are reported at a more distal location .

Some investigators divide the clinical examination into a swallowing mechanism examination (oromotor) and a feeding examination . The oromotor examination typically involves the analysis of components of the oral and pharyngeal stages of swallowing. Clinical swallowing examinations that have been proposed range from swallowing as little as 3 oz of water to a series of tasks designed to define the range, rate, coordination, and symmetry of movement of the lips, facial musculature, tongue, and pharynx and larynx and to reflect cranial nerve functioning for swallowing. In addition, most assessments also include activities to determine the patient’s language and cognitive abilities in relation to comprehension, attention span, and ability to follow instructions. These cognitive measurements often are limited in scope, however, and the information gathered from these tasks may not be integrated into the resultant analysis of the swallowing examination, except as a review of a patient’s “readiness” for assessment.

Ingestion of food or fluid via swallowing trials is not included routinely in a clinical bedside examination. The decision as to which patients will receive routine administration of food or fluid as part of the clinical bedside assessment frequently depends on the clinician’s judgment regarding the patient’s ability to deal with any aspiration that may occur or go undetected. If ingestion of oral intake is deemed relatively safe, the patient may be observed swallowing either one or more consistencies of food. These swallowing trials enable the clinician to review the swallowing mechanism in action. For instance, specific aspects of the swallow, such as laryngeal elevation, speed of swallow response, and oral clearance, can be evaluated during trial swallows. This information is not available from nonswallowing tasks, and it facilitates recommendations for feeding after completion of the assessment. Furthermore, instrumental tools, such as cervical auscultation and pulse oximetry, can be used during trial swallows in an effort to enhance the detection of penetration/aspiration at bedside . The relative value of incorporating trial swallows into a clinical swallowing evaluation is controversial, however. Because the ingestion of food or fluid brings with it potential risk for a patient suspected of having dysphagia, some authors believe that the risk–benefit ratio for this procedure is poor . They suggest that complexity of the pharyngeal stage of the swallow makes it impossible to judge the adequacy of the swallow accurately at the bedside. Consequently, the clinician may be left to guess the nature of the impairment, thus placing the patient at undue risk. Therefore some authors consider feeding trials unwarranted and argue that these trials should not be conducted without obtaining further diagnostic information from other instrumental swallowing examinations .

Clinical bedside assessment currently is the most widely used form of swallowing assessment. It is used frequently by health professionals as a first-line (and on occasion, as the only) means for investigating a clinical suspicion of a swallowing disorder. It is inexpensive, noninvasive, time efficient, and consumes few resources . It offers important information to help guide the clinician in the evaluation of a patient’s swallowing. Although bedside assessment is reported to be less sensitive than alternative instrumental assessment techniques in the identification of dysphagia and aspiration, most authors agree that it does provide valuable information for the prognosis and management of patients who have swallowing impairment . Ideally a clinical assessment provides information to help define potential causative factors, formulate a tentative hypothesis regarding the physiologic nature of the patient’s swallowing problem, and pinpoint the resultant level of breakdown in the neurophysiologic control system. It can facilitate the development of the preliminary treatment plan and the fabrication of further questions that must be answered to complete a diagnostic work-up. In addition, it may determine a patient’s suitability for further instrumental investigations.

Clinical bedside assessment versus videofluoroscopy

During the last decade the development of a variety of instrumental techniques has enabled empiric confirmation of dysphagia and aspiration, thus reducing the potential for intraobserver and interobserver variations. The validity of most clinical bedside techniques for assessing swallowing has been determined through comparison with an instrumental reference test. The most popular has been the videofluoroscopic examination (VFE). This instrumental examination often is considered the reference standard for the evaluation of dysphagia. Several authors have reported that VFE or dynamic imaging studies of the swallowing process provide the only reliable objective measurement of swallowing features and are essential for detecting and localizing abnormalities and/or functional impairments within this process .

The major advantage of VFE over the traditional clinical (“bedside”) swallowing assessment seems to be its ability to view features that are not observable in the clinical examination and therefore must be inferred from symptomatology. Critical information regarding the pharyngeal stage of swallowing is believed to be missing on clinical bedside assessments; thus, aspiration events may go undetected. Splaingard and colleagues , in a blinded study comparing observed clinical indicators with videofluoroscopic results, reported clinical signs to be unreliable indicators of the presence or absence of aspiration, identifying only 42% of the subjects who aspirated on VFE. Likewise, Logemann , in an unblinded study, found that even expert clinicians failed to identify approximately 40% of aspirating patients on clinical assessment and suggested that silent aspiration (aspiration without cough or any outward sign of difficulty) might be responsible. This author stated that bedside clinical assessment has proven unreliable in defining pharyngeal physiology because of the complexity of pharyngeal motor control during swallowing. Inaccurate clinical evaluation of the degree of aspiration can lead to an understaging of the risk for disability or to life-threatening complications of dysphagia.

Conversely, VFE has been criticized as an expensive and time-consuming procedure that is not commonly available to practicing clinicians . Although the usefulness of the direct visualization of swallowing is acknowledged, VFE exposes a patient to a degree of irradiation and may provide only a single, perhaps unrealistic, view of a patient’s swallowing within an unnatural setting. Lazarus and Logemann reported that many patients who demonstrated observable dysphagic deficits did not aspirate during VFE. Splaingard and colleagues state that the significance of aspiration identified by VFE for each individual patient remains debatable. Radiographic findings cannot necessarily be generalized to a functional situation (ie, a meal). Similarly, the procedural aspects of the technique are highly variable across settings, and the criteria for determining which patients require the procedure and the reliability of results across clinicians remains poor . Langmore and colleagues state that more research is required to determine the factors resulting in observer variation in videofluoroscopic diagnoses. Without uniform and accepted procedures for administration and scoring of these examinations, the ability to determine accurately the relative values of VFE or clinical assessments in the diagnosis and management of dysphagia remains dubious.

Currently available clinical bedside assessments

A number of clinical assessment tools have been proposed for the evaluation of swallowing ( Table 1 ). The choice of a clinical assessment method is central to the identification of the disorder and to the clinician’s theoretic framework for intervention. Various methods have been used, ranging from checklists to direct administration of food or fluids. Most clinical assessment methods have focused on the identification of symptoms or indicators of impaired swallowing. They can be considered bottom-up assessment models. The principal question that these tools aim to answer is “Does this person aspirate?” The tools used are designed to evaluate the various components of each swallowing phase or other matters considered indicative of the functioning at a particular phase (eg, vocal quality as an indicator of laryngeal function). The clinician then must interpret the information in light of his or her understanding of normal and abnormal swallowing physiology and neurophysiology. The focus of these examinations is primarily at the symptomatic level. Few, if any, clinical assessment methods map assessment findings directly to any model of swallowing neurophysiology. This procedure is left to the individual clinician and thus suggests erroneously that the physiologic organization and control of swallowing is indisputable and that a single theory prevails.

Review of clinical examination methods

Methods used in the clinical evaluation of swallowing fall into two main categories, water-swallow tests and (clinical) swallowing-mechanism examinations/checklists ( Table 2 ). Water-swallow tests require a patient to swallow water, and the effects of this event are recorded. Swallowing-mechanism examinations involve the administration of a series of oromotor/sensory and swallowing tasks designed to evaluate cranial nerve function and swallow physiology. Along with these tasks, some gross cognitive and language measures have been reported, such as the Mini Mental Status examination, the Glasgow Coma scale, and the presence/absence of dysphasia .

Table 2

Comparison of clinical assessment validity studies

Comparison study	DePippo et al	Nathadwarawala et al	Linden et al	Depipo et al	Nathadwarawala et al	Ott et al	Mari et al	Splaingard et al	Horner et al	Iskander et al	Kidd et al	Garon et al	Smithard et al	Mann et al	Tohara et al
Year	1992	1992	1993	1994	1994	1996	1997	1988	1990	1990	1995	1996	1997	2000	2003
No. patients	44	81	249	139	90	93	93	107	70	20	60	100	121	128	63
Diagnosis	rehabilitation neurologic	inpatient neurologic	mixed	rehabilitation neurologic	outpatient neurologic	mixed	in- and outpatients rehabilitation neurologic	adult and child rehabilitation patients	bilateral stroke	mixed	first-ever stroke	mixed	first-ever stroke	first-ever stroke	mixed
Referral pattern	consecutive admissions	unreported	referred	consecutive admissions	consecutive	referred	consecutive	referred	referred	referred	consecutive admissions	referred	consecutive admissions	consecutive admissions	referred
Variables measured	cough, voice, MBS aspiration	swallow speed, age, sex, perception of diagnosis	demographic and clinical variables, MBS subglottic penetration	demographic variables, diagnosis, cough, feeding time, non-oral feeding, % eaten, pneumonia,	swallow speed, age, sex, diagnosis perception, cough, clinical variables	demographic, clinical, and radiographic variables	demographic variables, history, clinical cough	demographic, clinical, radiographic variables	retrospective clinical and radiographic variables	demographic clinical and radiographic variables	demographic clinical and radiographic variables	cough, voice quality, radiographic variables	demographic, clinical and radiographic variables	demographic, clinical, and radiographic variables	demographic, clinical, and radiographic variables
Outcome of interest	aspiration	dysphagia	subglottic penetration	aspiration dysphagia	dysphagia	dysphagia	aspiration	aspiration	aspiration	dysphagia	aspiration	aspiration	aspiration	dysphagia aspiration	aspiration
Study methods	water-swallow test	swallow speed water-swallow test	clinical examination	water-swallow test checklist	water-swallow test checklist	clinical examination	water-swalow test checklist	clinical examination	clinical (file audit)	clinical examination	water-swallow test	water-swallow test	water-swallow test checklist	clinical examination	water-swallow test food test static radiographs
Reference test	radiographic	patient perception	radiographic	radiographic	clinical examination	radiographic	radiographic	radiographic	radiographic retrospective	radiographic	radiographic	radiographic	radiographic	radiographic	radiographic
Analysis method	sensitivity specificity	sensitivity specificity	chi squared discriminant	relative-risk Fisher’s exact tests	t -tests chi squared	% agreement rank order	sensitivity specificity factor analysis	sensitivity/ specificity chi squared t -tests	chi squared multivariate	Pearson product-moment correlations	chi squared (stratified) t -tests Fisher’s exact tests	chi squared Fisher’s exact tests	sensitivity/specificity chi squared multivariate	sensitivity/specificity chi squared multivariate	sensitivity/specificity Fisher’s exact texts

Only gold members can continue reading. Log In or Register to continue

Share this:

• Click to share on Twitter (Opens in new window)
• Click to share on Facebook (Opens in new window)

Related

Related posts:

Fiberoptic Endoscopic Evaluation of Swallowing Pediatric Dysphagia Treatment of Oral and Pharyngeal Dysphagia Dysphagia in Stroke and Neurologic Disease Dysphagia Rehabilitation in Japan Surgical Treatment of Dysphagia

Stay updated, free articles. Join our Telegram channel

Join