Assessment of Swallowing Disorders



Fig. 4.1
Lateral view on modified barium swallow study of a patient with a tracheostomy tube and a nasogastric tube. This example shows stasis in the vallecular with shallow penetration into the pyriform sinus post swallow



The MBS studies are often visually rated by the speech pathologist to determine the bolus transit time through the various phases of swallowing, location and cause of the stasis, compensatory maneuvers useful for partially or completely eliminating the stasis, timing of the swallow reflex, coordination of the structures involved in the swallow reflex, amount of aspiration/penetration, causes of aspiration/penetration, and compensatory strategies responsible for eliminating the penetration/aspiration. The eight-step penetration and aspiration scale developed by Rosenbek et al. [8] can be used to evaluate the degree of penetration and aspiration observed on MBS. The eight steps are:

1.

Material does not enter airway

 

2.

Remains above folds/ejected from airway

 

3.

Remains above folds/not ejected from airway

 

4.

Contacts folds/ejected from airway

 

5.

Contacts folds/not ejected from airway

 

6.

Passes below folds/ejected into larynx or out of airway

 

7.

Passes below folds/not ejected despite effort

 

8.

Passes below folds/no spontaneous effort to eject

 

In order to compare findings across clinics, it is critical to establish a minimum standard clinical protocol for evaluation and interpretation of findings that can be used across clinics. Martin-Harris et al. [9] reported a protocol called the new Modified Barium Swallowing Study Tool (MBSImP™©) that standardized the administration of contrast viscosities and reporting methods for the MBS. The MBSImP™© was tested in a heterogeneous sample of 300 patients to observed 17 well-defined physiologic swallowing components of lip closure, hold position/tongue control, bolus preparation/mastication, bolus transport/lingual motion, oral residue, initiation of the pharyngeal swallow, soft palate elevation, laryngeal elevation, anterior hyoid motion, epiglottic movement, laryngeal closure, pharyngeal stripping wave, pharyngeal contraction, PES opening, tongue base retraction, pharyngeal residue, and esophageal clearance in the upright position. Evaluation of the standardized MBSImP™© revealed high inter- and intra-rate reliability. Though MBSImP™© is useful, evaluation of the MBS relies on making visual perceptual judgments, which may be hard to compare across clinics.

Kendall et al. [10] reported a paradigm involving quantitative evaluation of the of MBS studies known as dynamic swallow study (DSS). The DSS allows objective evaluation of 17 measures that can be plotted for liquid boluses of 1, 3, and 20 cc. The 17 measures represent displacement and timing measurements, e.g., bolus transit, pharyngeal transit, oropharyngeal transit and hypopharyngeal transit, swallow gestures, soft palate elevation, aryepiglottic fold elevation, hyoid bone elevation, pharyngoesophageal sphincter opening, pharyngeal constriction, and epiglottic return. Objective evaluation of MBS represents an improvement over subjective reporting as it allows for evaluation of the examination without bias and makes it possible to assess subtle changes in swallowing function between and within subjects over time.

MBS is the mainstay for assessment of dysphagia. However, it does result in radiation exposure depending on the length of the study. Some patient’s may not be able to tolerate barium or could have an adverse allergic reaction to barium, which however is rare. Sometimes, because of the cognitive or physical limitation of size, it may not be able to position the patient upright for adequate imaging. In such instances, alternatives to MBS are often used for instrumental assessment of swallowing function.



Fiberoptic Endoscopic Examination of Swallow


Fiberoptic endoscopic examination of swallow (FEES) involves the use of a transnasal fiberoptic endoscope for evaluation of swallowing function. FEES was first introduced by Langmore et al. in 1988 [11] and has gained widespread popularity since its initial introduction. A standard fiberoptic or a distal chip tip endoscope can be introduced through the nasal passage unilaterally to visualize certain events of the oral transfer phase and the pharyngeal phase of swallow (Fig. 4.2). During FEES, it is recommended to place the tip of the endoscope in the pharyngeal area around the midportion of the base of the tongue rather than the laryngeal area to enable visualization of the bolus transit. Clinicians vary regarding their use of topical anesthetic to the nasal mucosa for examination of the swallow function. Topical anesthetic when used is used minimally to prevent any adverse effects of topical anesthetic on the pharyngeal mucosa.

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Fig. 4.2
Types of flexible endoscopes that can be used for fiberoptic endoscopic examination of swallow (FEES)

Premature spillage of bolus into the vallecula; base of tongue retraction; penetration of the bolus into the laryngeal vestibule (Fig. 4.3); stasis in the pyriform and vallecular spaces (Fig. 4.4) are some of the physiologic events that can be observed using FEES. In addition to the swallow physiology, FEES enables the clinician for evaluation of laryngeal structures and edema/erythema of the laryngeal structures due to laryngopharyngeal reflux. Typically, boluses of known viscosity are colored with green or blue dye for ease of visualization of possible penetration or aspiration on FEES. Compensatory maneuvers can be used during the test to ascertain their effectiveness in improving the safety of swallowing. FEES is particular beneficial for examining the structures of the larynx, location and severity of the stasis, and in providing biofeedback for the correct use of compensatory maneuvers or training exercises to improve swallow function. Some examples of compensatory strategies that can be used with FEES include modification of the bolus consistency and volume, changing the rate of delivery of the bolus, and modification of the sequence of bolus delivery. Some examples of therapeutic strategies that can be evaluated with FEES include effortful swallow, breath hold maneuver, base of tongue exercises, and thermal-tactile stimulation. FEES is particularly advantageous for evaluating of swallow function in critically ill patients at bedside and in determining the patient readiness for swallowing postradiation or robotic surgery for treatment of oropharyngeal carcinoma.

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Fig. 4.3
Fiberoptic endoscopic examination of swallow (FEES) revealing premature spillage of liquid into the laryngeal vestibule


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Fig. 4.4
Fiberoptic endoscopic examination of swallow (FEES) revealing stasis in the vallecular space

Flexible endoscopic evaluation of swallow with sensory testing (FEEST) is a modality where both sensory and motor tests for swallowing can be performed, unlike FEES, which only examines the motor component of swallowing. FEEST was first introduced by Aviv et al. in 1993 [12]. FEEST examines the laryngeal closure reflex, which is critical for the airway protection. Pressure and duration of calibrated pulses of air are delivered to the hypopharyngeal tissue, which is known to be innervated by the superior laryngeal nerve that triggers the laryngeal adductor reflex [13]. Several studies have been conducted demonstrating a positive relationship between edema of the hypopharyngeal structures and reduction in the laryngeal airway reflex on FEEST examination [14, 15]. Specialized equipment that delivers calibrated puffs of air is required for FEEST and has not received widespread usage across clinics.

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Jun 3, 2017 | Posted by in OTOLARYNGOLOGY | Comments Off on Assessment of Swallowing Disorders

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