Office evaluation of swallowing.

A routine history and physical examination provide little information that allows otolaryngologists to distinguish between patients who are at risk for aspiration and those who have a "safe swallow." Specific clinical assessment of swallowing involves evaluation of oral control, lingual activity, oral residue, laryngeal excursion, the initiation and timing of the swallow, voice quality, and cough after the swallow. These clinical factors are observed first during a dry swallow and subsequently while the patient swallows food and liquid of various consistencies.

Although the practice of performing a clinical assessment alone (bedside swallow) is common, evidence suggests that it is a poor evaluative measure. In a recent study, Leder and Espinosa found that while the sensitivity of clinical assessment was 86%, its specificity was only 30% and its false-positive rate was 70%. (1)

To better evaluate dysphagic symptoms, instrumental assessments are often needed. A video fluoroscopic swallow study (VFSS), also called a modified barium swallow, has been the traditional method of instrumental assessment, and until recently it was the gold standard for dysphagia evaluation. After a patient is fed barium mixed with various consistencies of food and liquid, radiographic images are obtained to look for abnormalities in swallow function. Anatomic information is also gathered, although

it is cursory. When findings are abnormal, compensatory strategies are often performed.

A newer instrumental assessment technique is called fiberoptic endoscopic evaluation of swallowing (FEES). (2) FEES can be combined with sensory testing (FEESST) to obtain further information regarding the status of laryngeal sensation. Today, both FEES and FEESST are commonly used in clinical practice. With improvements in technology and techniques, FEES and FEESST are now considered to be at least equal to and in some ways superior to VFSS.

FEES

Equipment and setup. FEES is usually performed by two clinicians--ideally, a physician skilled in endoscopy and a speech-language pathologist. A video tower is usually positioned at the patient's side and facing the examiner. The typical setup also includes a standard flexible laryngoscope and a light source.

In our opinion, a video tower is essential for several reasons:

* First, it allows everyone who is present during the procedure (physician, therapist, patient, and family members) to witness aspects of the swallow. This provides important feedback.

* Second, it allows the physician to play back and review the examination and, when serial evaluations are performed, to compare the new findings with those of previous investigations. (The components of the video tower are discussed in the first article in this supplement, "Topical anesthesia of the airway and esophagus," page 2.)

* Third, it provides documentation, which may be necessary for billing or legal purposes.

An important key to swallow assessment is to use a camera that has a rapid shutter speed (information on shutter speed should be available from equipment-sales representatives). A short exposure time reduces the "white-out" period that occurs when the pharynx contracts around the tip of the endoscope. The reduction of white-out allows for a more complete assessment during the active swallow.

Various supplies are also necessary for FEES, such as liquids, foods of different textures, and utensils (table 1).

Protocol. The patient typically is seated in a chair in a comfortable position. Topical anesthesia and/or decongestion in the nasal cavity generally is not used. However, a recent study by Johnson et al demonstrated that aerosolized topical anesthetics delivered into the nose had no measurable effect on laryngeal sensation. (3)

The scope is lubricated and passed transnasally, and the pharyngeal and laryngeal structures are examined. The clinician should pay particular attention to the presence of pooled secretions, which have been associated with an increased risk of aspiration. (4) Vocal fold function should also be assessed. Of particular importance is the presence of vocal fold paralysis or paresis. The mucosa should be assessed for the presence of excessive dryness.

Next, the patient is asked to perform a dry swallow and emit a high-pitched "i" sound. During this action, the clinician assesses the pharyngeal squeeze, the timing of the swallow, epiglottic inversion (figures 1 and 2), and pooled secretions. The patient is then asked to swallow a series of dyed food boluses of various consistencies. These boluses are typically given in the following order: a honey-thick liquid, a puree, a solid, a nectar-thick liquid, and a thin liquid such as water (table 1). Thicker liquids are typically used first because they tend to confer the least risk of aspiration; thin liquids tend to carry the highest risk of aspiration, and therefore they are used last. The extent of the testing is adjusted according to the clinical need or impression.

[FIGURES 1-2 OMITTED]

Various factors are assessed during bolus intake: the timing of the swallow, penetration, aspiration, the presence of residue, and whether the patient requires multiple swallows to clear the bolus. Penetration indicates the entry of a portion of a food or liquid bolus into the laryngeal inlet (figure 3, A). Aspiration indicates the entry of a portion of a bolus below the level of the vocal folds (figure 3, B).

[FIGURE 3 OMITTED]

The larynx should be carefully observed during the postswallow period (occasionally for as long as 1 or 2 minutes) because portions of the bolus can accumulate in the pyriform sinuses and subsequently spill into the larynx. This delayed aspiration or postswallow aspiration is usually missed on VFSS, but it can be captured on FEES. Moreover, a bolus can occasionally be observed reentering the pharynx after it has passed into the esophagus. This is often a sign that a Zenker's diverticulum is present.

At the conclusion of the standard FEES protocol, tracheoscopy is performed. This allows the clinician to confirm whether or not food or liquid was aspirated. Because of the white-out effect, subtle aspiration during the swallow can be missed. A patient who cannot tolerate tracheoscopy is asked to perform a throat-clear, which will bring any aspirated tracheal material back into the laryngopharynx.

After the completion of the assessment phase of FEES, compensatory techniques can be performed while the endoscope remains in place. Such techniques include a supraglottic swallow, cyclic ingestion, head turn, double-swallow, and head tilt. Feedback from FEES helps establish the best strategy and emphasizes the value of this technique to the patient and family members.

FEESST

FEESST was first described by Aviv et al in 1998. (5) During this test, a calibrated pulse of air is delivered to the laryngeal mucosa. The afferent input travels via the superior laryngeal nerve. If the sensation reaches a suprathreshold level, the result is a reflex adduction of the vocal folds via the recurrent laryngeal nerve. This reflex are is known as the laryngeal adductor reflex. It is an important protective mechanism that helps guard against aspiration. By assessing the laryngeal adductor reflex, FEESST provides additional information regarding the protective mechanisms of the patient's swallow. Sensory testing may also help determine candidacy for nerve transposition surgery. (6)

Equipment. In addition to the standard FEES equipment, FEESST requires two additional items: a calibrated air-pulse sensory stimulator and a flexible endoscope with a side channel for the delivery of the air pulse (both items: Pentax Precision Instrument Corp.; Orangeburg, N.Y.) (figure 4, A). If the special endoscope is not available, the clinician can use an alternative: a Slide-On sensory sheath (Vision Sciences; Natick, Mass.) that can be placed over any standard flexible laryngoscope (figure 4, B).

[FIGURE 4 OMITTED]

Technique and interpretation. When sensory testing is desired, it is usually performed prior to FEES. The endoscope is positioned over the junction of the ipsilateral arytenoid and aryepiglottic fold. The endoscope is considered to be in a good position if a white-out is noted on the screen (approximately 2 mm from the mucosa) (figure 5, A). A calibrated pulse of air is then delivered (figure 5, B). The endoscope is then pulled back to visualize the larynx. The examiner watches for the laryngeal adductor reflex. A positive response indicates suprathreshold stimulation. Several different pressures are tried (typically low to high) until a threshold is determined and confirmed. The contralateral side is then tested. These values are then compared with established diagnostic values to determine the presence or absence of a sensory deficit (table 2).

Benefits of FEES and FEESST

FEES and FEES ST offer many advantages over traditional instrumental methods of swallow assessment. The biggest benefit for otolaryngologists is that these tests can be easily performed in the office with only a small amount of additional equipment. Another benefit is that these tests provide immediate visual feedback.

Compared with VFSS, FEES provides better anatomic information, including evidence of the presence or absence of pooled secretions. Several studies have shown that FEES is also more sensitive than VFSS in evaluating swallowing initiation, penetration, aspiration, and pharyngeal residue. (6-9) Finally, in a large prospective study, Aviv compared the ability of FEESST and VFSS to prevent aspiration pneumonia in patients with dysphagia. (10) He found no statistically significant difference in the incidence of pneumonia in the two groups.

These studies have demonstrated the importance and comparative value of FEES and FEESST. We believe that as more otolaryngologists become familiar with FEES and FEESST, these procedures will become an indispensable part of the office-based assessment of dysphagia.

Table 1. Requisite supplies for FEES and
FEESST

Thickener (available commercially as Thick & Easy;
Hormel Health Labs; Austin, Minn.)

Blue or green food coloring

Honey-thick liquids (thick juice with the consistency
of honey, or thickener mixed with water)

Puree (pudding or applesauce)

Solid food (crackers)

Nectar-thick liquids (thick juice with the consistency
of nectar, or thickener mixed with water)

Thin liquids (e.g., water)

Spoons

Straws

Cups

Table 2. Diagnostic values for laryngeal
FEESST

Value              Diagnosis

<4 mm Hg           Normal sensory function
4 to 6 mm Hg       Moderate sensory deficit
>6 mm Hg           Severe sensory deficit

References

(1.) Leder SB, Espinosa JF. Aspiration risk after acute stroke: Comparison of clinical examination and fiberoptic endoscopic evaluation of swallowing. Dysphagia 2002; 17:214-18.

(2.) Hiss SG, Postma GN. Fiberoptic endoscopic evaluation of swallowing. Laryngoscope 2003;113:1386-93.

(3.) Johnson PE, Belafsky PC, Postma GN. Topical nasal anesthesia and laryngopharyngeal sensory testing:Aprospective, double-blind crossover study. Ann Otol Rhinol Laryngol 2003;112:14-16.

(4.) Murray J, Langmore SE, Ginsberg S, Dostie A. The significance of accumulated oropharyngeal secretions and swallowing frequency in predicting aspiration. Dysphagia 1996; 11:99-103.

(5.) Aviv JE, Kim T, Sacco RL, et al. FEESST: A new bedside endoscopic test of the motor and sensory components of swallowing. Ann Otol Rhinol Laryngol 1998;107:378-87.

(6.) Aviv JE, Mohr JP, Blitzer A, et al. Restoration of laryngopharyngeal sensation by neural anastomosis. Arch Otolaryngol Head Neck Surg 1997;123:154-60.

(7.) Langmore SE, Schatz K, Olson N. Endoscopic and videofluoroscopic evaluations of swallowing and aspiration. Ann Otol Rhinol Laryngol 1991;100:678-81.

(8.) Leder SB, Sasaki CT, Burrell MI. Fiberoptic endoscopic evaluation of dysphagia to identify silent aspiration. Dysphagia 1998; 13: 19-21.

(9.) Wu CH, Hsiao TY, Chen JC, et al. Evaluation of swallowing safety with fiberoptic endoscope: Comparison with videofluoroscopic technique. Laryngoscope 1997; 107:396-401.

(10.) Aviv JE. Prospective, randomized outcome study of endoscopy versus modified barium swallow in patients with dysphagia. Laryngoscope 2000; 110:563-74.