This article reviews the current standard of care for the instrumental evaluation of swallow function using the modified barium swallow (MBS) and the functional endoscopic evaluation of swallowing (FEES). Both the MBS and FEES are valuable procedures for evaluating dysphagia and show good agreement with diagnostic findings as related to tracheal aspiration, laryngeal penetration, pharyngeal residue, diet level, and compensatory swallow safety strategies. The use of the MBS and FEES has advantages and disadvantages and both should be considered the gold standard for evaluating swallow function.
Key points
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It is important for physicians and clinicians to have a basic understanding of the protocols for both the modified barium swallow (MBS) and functional endoscopic evaluation of swallowing (FEES), including indications for use, advantages, and disadvantages.
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The MBS and FEES are valuable swallowing diagnostic tools and show good agreement with diagnostic findings as related to tracheal aspiration, laryngeal penetration, pharyngeal residue, diet level, and compensatory swallow safety strategies.
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The determination of which procedure is needed to evaluate swallowing function is driven by specific patient characteristics and the field of view necessary to evaluate the suspected dysphagia.
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Both the MBS and FEES should be considered the gold standard for evaluating the swallow.
Nature of the problem
Dysphagia can be a symptom of several different underlying medical conditions or diseases ( Fig. 1 ). The swallowing disorder may result from either a specific anatomic (ie, tumor or genetic malformation) or physiologic/functional issue (ie, sensation loss, coordination, or muscle paralysis). Regardless of the underlying medical condition, in order to effectively treat swallowing disorders such as providing appropriate dietary recommendations, behavior management strategies, and rehabilitation exercises, the health care team first need to correctly identify the specific biomechanical aspects of the swallowing function through the appropriate use and interpretation of a diagnostic swallow procedure. The purpose of a diagnostic swallow procedure is to assess dysphagia and when appropriate make recommendations for diet level, swallow safety strategies, and swallowing rehabilitation interventions.
| FEES | Fiber-optic endoscopic examination of the swallow |
| MBS | Modified barium swallow |
| SLP | Speech language pathologist |
The 2 most common diagnostic swallowing procedures available are the modified barium swallow (MBS) and the functional endoscopic evaluation of swallowing (FEES). Both procedures have been validated and have published evidence-based guidelines developed in accordance with the scientific evidence available in the literature for the performance and interpretation of these examinations. The MBS has been available since the 1950s and incorporates the use of a radiograph along with barium in order to evaluate the physiology of the swallow function. The MBS is known by several different names, such as the videofluoroscopic swallow study, cookie swallow, pharyngogram with videorecording, or video pharyngogram.
The FEES, compared with the MBS, is a newer procedure and evaluates swallow function using nasal endoscopy. The FEES is also known as the fiber-optic endoscopic evaluation of swallowing or the videoendoscopic evaluation of the swallow. The challenge for physicians and clinicians is to determine when the MBS or the FEES is the preferred swallowing test. This article describes both procedures, compares and contrasts the MBS and FEES, and discusses clinical indications for each procedure in order to assist the health care provider with this decision-making process.
Nature of the problem
Dysphagia can be a symptom of several different underlying medical conditions or diseases ( Fig. 1 ). The swallowing disorder may result from either a specific anatomic (ie, tumor or genetic malformation) or physiologic/functional issue (ie, sensation loss, coordination, or muscle paralysis). Regardless of the underlying medical condition, in order to effectively treat swallowing disorders such as providing appropriate dietary recommendations, behavior management strategies, and rehabilitation exercises, the health care team first need to correctly identify the specific biomechanical aspects of the swallowing function through the appropriate use and interpretation of a diagnostic swallow procedure. The purpose of a diagnostic swallow procedure is to assess dysphagia and when appropriate make recommendations for diet level, swallow safety strategies, and swallowing rehabilitation interventions.
| FEES | Fiber-optic endoscopic examination of the swallow |
| MBS | Modified barium swallow |
| SLP | Speech language pathologist |
The 2 most common diagnostic swallowing procedures available are the modified barium swallow (MBS) and the functional endoscopic evaluation of swallowing (FEES). Both procedures have been validated and have published evidence-based guidelines developed in accordance with the scientific evidence available in the literature for the performance and interpretation of these examinations. The MBS has been available since the 1950s and incorporates the use of a radiograph along with barium in order to evaluate the physiology of the swallow function. The MBS is known by several different names, such as the videofluoroscopic swallow study, cookie swallow, pharyngogram with videorecording, or video pharyngogram.
The FEES, compared with the MBS, is a newer procedure and evaluates swallow function using nasal endoscopy. The FEES is also known as the fiber-optic endoscopic evaluation of swallowing or the videoendoscopic evaluation of the swallow. The challenge for physicians and clinicians is to determine when the MBS or the FEES is the preferred swallowing test. This article describes both procedures, compares and contrasts the MBS and FEES, and discusses clinical indications for each procedure in order to assist the health care provider with this decision-making process.
MBS procedure
Key Points of Procedure
The MBS allows for the identification of normal and abnormal anatomy and physiology of the swallow as viewed by radiograph. The MBS also evaluates the integrity of airway protection before, during, and after the swallow. The MBS is used to evaluate the effectiveness of bolus modifications, postural changes, and swallowing maneuvers to improve swallowing safety and efficiency. The potential variations to the MBS protocol along with equipment needs and radiation considerations are reviewed in this section.
Technique Summary
The MBS examination involves the use of barium and fluoroscopy to assess the oral and pharyngeal phase of the swallow. The fluoroscopic images allow for the motion-picture radiograph of the dynamic swallow function. The assessment of the esophagus is usually not a major component of the MBS; however, a screening of the esophageal phase of the swallow during the MBS may be conducted. The MBS is usually recorded for the availability of further review and analysis. Traditionally, the MBS is completed in the radiology department with a radiologist, radiology technician, and a swallowing clinician (usually a speech language pathologist [SLP]).
MBS Protocol Summary
The standard MBS protocol developed by Logemann has been the basis for the development of many subsequent protocols. Although in clinical practice there are many variations in the standard clinical protocol for the MBS, Table 1 summarizes the details of most MBS protocols as well as the potential variations. The challenge in clinical practice is to determine when it is necessary to perform a standardized protocol versus performing a tailor-made study designed to match typical eating behaviors. In addition, when designing an MBS protocol for clinical practice, the examiner must take into account how to obtain as much information about the swallow function with the minimum amount of radiation exposure. If advancing a patient to test a particular bolus consistency or size is determined not safe for the patient, then it is often deferred during the MBS protocol.
| MBS Protocol | Potential Variations |
|---|---|
| Type of barium | Specific type of barium used during the MBS (eg, Varibar [E-Z – EM Inc., Melville, NY]) |
| Ratio of food to barium mixtures | Specific recipes used for mixing barium suspension with food and liquid |
| Bolus consistencies | Honey thick liquids, nectar thick liquids, thin liquids, pureed, ground, chopped, bread/cookie, raw vegetable |
| Bolus size | 1 mL, 3 mL, 5 mL, small cup sip, uncontrolled large sip, consecutive swallows, 30 mL |
| Method of bolus presentation | Clinician administered vs patient self-feeding; liquids by spoon, cup, and straw |
| Sequence of bolus presentation | Variation in the specific consistency to begin protocol (ie, thin vs nectar thick vs pudding) |
| Number of bolus presentations for each specific bolus | Many protocols range from 1 to 3 presentations for each bolus |
| Evaluation of bolus modifications, postural changes, and swallowing maneuvers to improve swallow efficiency and safety | Interventions such as sour boluses, chin tuck, head turn, oral holding, supraglottic swallow, supersupraglottic swallow, throat clear, multiple swallows, Mendelsohn maneuver |
| Esophageal screen | Debate regarding if esophageal screen should be routinely performed within the MBS protocol and how it should be conducted |
Equipment
The basic fluoroscopic unit required for completion of the MBS consists of a constant radiograph source, a radiograph detector, a monitor, and recording system. The constant radiograph source of the fluoroscopy system is the radiograph tube powered by a moderately complex generator, which provides the radiograph beam. The energy and quantity of radiographs are modulated by a feedback mechanism within the unit, and the appropriate amount of radiographs is produced based on the thickness and density of the tissue/body part. During the MBS, the patient must be correctly centered in order for the feedback system of the radiograph machine to function properly. Placed between the patient who is receiving the MBS and the radiograph tube is a collimator, which can be adjusted to limit the size and shape of the radiograph beam. The radiograph detector of the fluoroscopy system is the image intensifier, which is an electronic cylinder that converts radiograph energy into light. This step is required in order for the radiograph to be visualized by the camera for viewing on a monitor and be available for recording. Specialized chairs have been made for the MBS examinations to fit into the space between the table and the image intensifier tower. Furthermore, mobile fluoroscopic units (C-arm systems) have fluoroscopic capability and may also be used for MBS. When using a C-arm system, a regular chair or wheelchair may be used for the patient.
Radiation
The amount of radiation exposure is dependent on time exposure, distance from the radiograph tube, and shielding. Radiation dose during the MBS is lower than a routine chest computed tomography (CT) and it would take more than 40 MBS examinations in a year to exceed the annual radiation exposure dose limits. Using a recording device assists with reducing the amount of radiation time that the patient and health care team may be exposed to by reducing the number of swallows required during the MBS. During the MBS, the patient must remain close to the radiograph tube in order to obtain the radiograph images; however, because of radiation scatter, health care team members should distance themselves as far as possible from the radiograph tube. This distance may be accomplished by allowing the patient to feed themselves whenever possible. Shielding protocols should be followed in order to reduce radiation exposure. For patients (especially children), a lap shield can be used to protect reproductive organs from radiation. Health care team members conducting the MBS, if they are not behind a lead glass shield, should also wear a thyroid collar, full lead apron, and protective eye goggles.
FEES procedure
Key Points of Procedure
The FEES examination allows for an evaluation of the anatomic structures, secretion levels, swallowing ability, and sensory ability. The use of topical anesthesia, sensory testing, assessment of secretion level, swallowing ability, use of blue food coloring, and pediatric considerations are discussed in this section.
Technique Summary
The FEES examination requires a flexible laryngoscope with a halogen or xenon light source. The endoscopist can visualize the image directly through the eyepiece or by using a chip camera attached to the laryngoscope. When using a chip camera, the image can then be viewed on a monitor and recorded for further analysis. A complete FEES examination includes an assessment of the anatomic structures at rest and in movement, the accumulated oropharyngeal secretion level, and bolus flow of various foods and liquids while swallowing. If difficulty with swallowing is observed, then there are several therapeutic interventions that may be performed during the FEES in order to evaluate the effectiveness of the intervention.
Assessment of Anatomy
The FEES not only identifies the signs and symptoms of dysphagia, it is also capable of providing a view of the anatomy and physiology of the swallow. A common physiologic abnormality observed during the FEES is the presence of reduced vocal fold mobility. This reduction in vocal fold mobility has been associated with increased incidence of aspiration.
Topical Anesthesia
The use of a topical anesthesia during the FEES is part of some protocols. Although some physicians and clinicians choose to use a topical anesthesia during the FEES, a systematic review of the literature found no evidence to support reduce pain or discomfort when using a topical treatment before nasal endoscopy. In addition, for nonphysicians performing the FEES, the administration of a topical anesthesia varies by state laws, and clinicians should be aware of local rules and regulations.
Sensory Testing
Understanding the relationship between sensory input, airway protection, and swallowing ability is an important clinical component of the FEES. During the FEES, sensation may be either directly assessed with light touching of the endoscope to the pharyngeal/laryngeal structures or indirectly assessed based on the patient’s response to the presence of pharyngeal residue, laryngeal penetration, or aspiration. Further, there are specialized endoscopes with an instrument channel that allows for the delivery of calibrated puffs of air to the mucosa of the larynx. The addition of the puffs of air during the examination is known as the fiber-optic endoscopic evaluation of swallowing with sensory testing (FEESST) and was first described by Aviv and colleagues. During the FEESST, sensation is inferred by monitoring the laryngeal adductor reflex, which is elicited after the delivery of the puffs of air. The degree of sensory deficit is inferred by the amount of calibrated puffs of air required to elicit the laryngeal adductor reflex. The utilization of FEESST is not a required element for the FEES.
Secretion Level
Suspected or observed difficulty swallowing saliva or secretions is a clinical indication for the performance of the FEES. Before any bolus presentation, the clinical protocol involves an observation of secretions, including describing the amount and location. Evaluation of secretion levels with a reliable measure is imperative, because clinicians should be able to use this information in order to quickly differentiate between safe levels of accumulated secretions and those that are dangerously high. Furthermore, by being able to quickly discern the secretion levels, the examiner is potentially able to provide better and more appropriate treatment, thus reducing the incidence or complication of aspiration pneumonia and its associated health care costs. Various secretion scales are available in the literature, and Table 2 provides an example of a 3-point secretion scale developed by Donzelli and colleagues, which measures the presence, amount, and location of oropharyngeal secretions. With this 3-point secretion scale, the score that the patient receives is the point of maximum secretions present (no transition score is available). A higher score indicates more secretions. The 3-point secretion scale also distinguishes between laryngeal penetration and aspiration of secretions. The predictive validity of the 3-point secretion scale in relation to aspiration revealed that this scale is correlated to aspiration (Spearman ρ .516, P <.0001) and to diet outcome recommendations (Spearman ρ .72, P <.0001), with patients receiving a higher secretion level being more likely to aspirate and also to receive a lower diet level or be nil by mouth.
