The repetitive saliva swallowing test (RSST ) was developed to safely and simply screen patients with functional dysphagia . It detects the patient’s ability to voluntarily swallow repeatedly and correlates the results with the risk of aspiration. The patient stays in a resting posture and is asked to repeatedly swallow saliva (dry swallow ) as many times as possible within 30 s. The examiner counts the number of swallows by palpation or inspection of laryngeal elevation movement during the swallowing reflex (Fig. 5.1). A patient with two or fewer dry swallows within 30 s is likely to have dysphagia associated with aspiration and should be further investigated.

The sensitivity and specificity of the RSST to detect aspiration diagnosed using VF as reference test are 0.98 and 0.66, respectively [11, 12]. However, the RSST has limited clinical applicability in patients with cognitive or linguistic dysfunction because these patients may lack the ability to follow instructions.

The modified water swallowing test (MWST ) is used to detect aspiration when swallowing water and monitoring the response. A 3-mL volume of cold water is placed on the floor of the mouth with a syringe, and the patient is instructed to swallow the water followed by two saliva swallows (Fig. 5.2). If the patient is unable to swallow or experiences dyspnea , coughing, or wet-hoarse dysphonia after swallowing, a score of 1–3 is recorded and the test is terminated. If the patient is able to swallow the water safely, a score of 4 or 5 is recorded depending on the patient’s ability to perform the two dry swallows afterward.

Breathing , coughing, and voice quality are scored using a five-point scale (Table 5.3).

The entire procedure is repeated twice more. The final score is determined as the lowest score of any trial. This test is an easy, simple, and safe method with which to evaluate swallowing function.

The sensitivity and specificity of the MWST to detect aspiration using VF for concurrent validity are 0.70 and 0.88, respectively, when the cutoff score is 3 [13, 14].

The food test is a modification developed to screen for solid food dysphagia . The procedure and scoring are nearly identical to those of the MWST . A 4-g bolus of pudding or jelly is placed on the dorsum of the tongue with a spoon, and the patient is then instructed to swallow. In addition to scoring the components of MWST, oral residue after swallowing must be inspected (Fig. 5.3; Table 5.4).

The sensitivity and specificity of the food test to detect aspiration as diagnosed by VF are 0.72 and 0.62, respectively, when the cutoff score is 4 [14].

The 30-mL water swallowing test (WST ) was originally described by Kubota [15, 16] using 30 mL of water at room temperature to detect aspiration. The patient is asked to drink water from the cup in the sitting position as usual. The drinking profile is based on a five-point scale, and the occurrence of drinking episodes (described below) and duration of drinking are monitored and assessed (Table 5.5).

A comprehensive history must include the information shown in Table 5.7.

This information is ideally obtained directly from the patient. However, when the patient is unable to provide this information because of a limited cognitive status or language restriction, the history of the swallowing problem is acquired and validated by the patient’s family or caregiver, the medical team, and/or the medical record. Knowledge of the potential etiology of the dysphagia is critical. A curable or ameliorating etiology , such as infection or stroke , respectively, can suggest the potential to improve the patient’s swallowing ability. Conversely, a progressive disease such as a neurodegenerative disease or amyotrophic lateral sclerosis suggests a poor swallowing prognosis over time. This information affects the ability to establish a feasible and appropriate treatment plan.

It is important to assess the patient’s physical findings in terms of both structure and function. This assessment consists of various general assessments (described below) and evaluation of the cranial nerves , particularly cranial nerves V, VII, IX, X, and XII because these are strongly associated with the motor and sensory functions of swallowing.

Swallowing examination using VF is a treatment-oriented evaluation that provides real-time visualization of the bolus trajectory in the oral cavity, oropharynx , hypopharynx , and esophagus using various consistencies and volumes of barium -coated trial materials.

VF has been proposed as the gold standard assessment method with which to establish a standard for image evaluation and is considered a mandatory tool for swallowing evaluation. It allows for a kinematic evaluation during the study and a more detailed kinematic analysis using the recorded image after the study, contributing to the establishment of a treatment plan.

VF provides two essential feedback parameters for treatment: knowledge of results and knowledge of performance. Knowledge of results is the feedback regarding whether aspiration and/or residue is present. Knowledge of performance is the feedback regarding how to eliminate this aspiration/residue. Thus, for knowledge of results, identifying the least difficulty task that can prevent aspiration and/or residue is essential, and for knowledge of performance, detecting the tip to eliminate aspiration and/or residue is essential. Determining appropriate food modification, postural techniques, and swallowing maneuvers as the least difficulty task and tip are the basis of evaluation. VF also allows the clinician to assess the availability, adequacy, and effect of the intervention in terms of reaching the treatment goal.

Four evaluation points are important when performing VF :

The results of these evaluations will help to determine the most effective strategies (e.g., bolus modification or postural techniques during VF ) that ensure efficient and safe swallowing. Other details should also be observed depending on the individual patient’s problems.

Laryngeal penetration and the risk of aspiration associated with the bolus type are observed while performing VF . The order of the tests is not fixed; the clinician adapts the examination to the individual patient. The clinician can select the bolus materials depending on the patient’s swallowing impairment and complaints about foods that are difficult to swallow. According to the differences between eating and drinking , clinicians should evaluate both of these behaviors in terms of the chew–swallow complex . One study demonstrated that the act of chewing was a prime determining factor of the chew–swallow complex during stage II transport of the process model [17].

As seen in Fig. 5.8, the two-phase food (mixed food ) is associated with the highest risk of aspiration because the bolus head is significantly lower in the food pathway at swallowing onset than either liquid or corned beef hash . The leading edge of the two-phase food reaches the vallecula or a lower area of the hypopharynx before swallowing onset . This means that the patient’s chewing manner influences the depth of the leading edge of the bolus at the onset of pharyngeal swallow. This occurs even when drinking liquid by performing chewing . Clinicians should therefore assess the chew–swallow complex in addition to performing conventional VF , and a two-phase food should be used to evaluate the risk of aspiration (Table 5.8).

Patients with dysphagia should be assessed with caution when eating multi-textured food to clarify the most appropriate bolus types for each patient. Prepared bolus materials should be initially tested from the safest and easiest to the most difficult materials, and the patient should begin the examination using a small amount of liquid barium or a small bolus of food to enable safe assessment of the patient’s basic swallow physiology and clarification of further management. If the bolus can still be safely swallowed after modification of its consistency and volume , the study proceeds by administration of the next bolus with a higher risk of aspiration (more difficult task). This step-by-step administration is continued until the clinician detects the task that results in aspiration. Various foods and liquids that differ in volume , consistency , and texture are used. Liquid barium is administered by syringe for 4- and 10-mL boluses placed under the tongue and by cup or straw for 30-g boluses to observe sequential drinking . **The patient is asked to hold the bolus in his or her mouth until instructed to swallow.

In addition to modification of the boluses administered during VF , postural techniques (e.g., head rotation , trunk rotation , reclining posture, head/neck flexion ) and swallowing maneuvers (e.g., super-supraglottic swallo w, Mendelsohn maneuver , Effortful swallow ) can be utilized to enhance safety and facilitate selection of appropriate treatment. These procedures help to determine how to improve the oropharyngeal swallow and return the patient to full oral intake as quickly as possible (Table 5.9).

The most important image of the swallowing study is the lateral view, which enables observation of the movement of the tongue base , soft palate elevation , hyolaryngeal elevation , laryngeal closure , contraction of the pharyngeal constrictor, and opening of the upper esophageal sphincter (UES). However, the anteroposterior view must also be assessed because it provides important clinical information regarding the pharyngeal constriction , the laterality of bolus flow (symmetrical characteristic), the side on which the pharyngeal residue is located, and anatomical abnormalities such as pharyngeal diverticula. This view also allows for assessment of the esophageal stage , including delayed esophageal transit time (<30 s is acceptable) and gastroesophageal regurgitation (Table 5.10).