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Upon Completion, The Reader Will Be Able To:

• Define Dysphagia
• State the anatomical landmarks and functions of the larynx, and how it relates to the normal swallow
• Describe the Oral Preparatory phase of the normal swallow
• Describe the Oral phase of the normal swallow
• Describe the Pharyngeal phase of the normal swallow
• Describe the Esophageal phase of the normal swallow
• State the three factors that the normal, safe swallow is dependent on
• Understand why the Speech-Language Pathology obtains a detailed history from the patient prior to the Modified Barium Swallow Study
• List some of textures and consistencies that are swallowed during the procedure
• Briefly describe the Fiberoptic Endoscopic Evaluation of Swallowing (FEES)

Outline

1. Introduction
   1. Accepted procedure for assessing dysphagia
   2. Radiologic Technologists need for understanding
2. History and development of the Modified Barium Swallow Study
   1. Assessment and treatment of dysphagia began in the late 1970's
   2. The shift to Speech-language Pathologists
   3. The evolution to video-recording
3. What is Dysphagia?
   1. The etiologies
   2. The sequelae
4. Anatomical landmarks, functions of the larynx, and normal swallowing
   1. The oral preparatory phase
   2. The oral phase
   3. The pharyngeal phase
   4. The esophageal phase
5. Abnormal swallowing
6. Usual procedure
   1. Speech-Langauge Pathologists interview
   2. Positioning of the patient and equipment
   3. Protocols
   4. Treatment techniques attempted
   5. Reliability/validity
   6. Alternative examination: FEES
   7. MBSS versus the esophogram
   8. Role of the Speech-Language Pathologist and Radiologist
7. Conclusion

Introduction

The Modified Barium Swallow Study (MBSS), also known as video-fluoroscopic swallow study, is a common, accepted procedure for the assessment of dysphagia (difficulty swallowing) in patients of all ages. In many acute care facilities, MBSS exams represent a significant use of fluoroscopic equipment. It is helpful for Radiologic Technologists to have an understanding of these examinations and why they are performed. Even though their role in this procedure is limited to assisting the Speech Pathologist and Radiologist, the MBSS is an important exam that may have a large impact on the patient's life.

History and Development of the MBSS

The multidisciplinary study of swallowing and swallowing disorders has evolved over the past thirty years. Prior to 1976, various types of dysphagia were recognized—such as dysphagia associated with stroke or dysphagia due to esophageal dysmotility—but the coordinated assessment and, more importantly, treatment of patients with swallowing disorders began in the late 1970s. In some parts of the country, occupational therapists conducted swallowing assessments and treatment initially, but for the most part, swallowing assessment and treatment became associated with the scope of practice of Speech-language Pathology (SLP) and the vast majority of swallowing assessments since that time have been done by Speech-language Pathologists. Although the reasons for this shift are not clear, a primary reason appears to be that SLP already possessed knowledge of the anatomy and physiology of the aerodigestive tract by virtue of their study of speech, language, and voice disorders.

Early on in the study of dysphagia, the process of video-recording the dynamic process of swallowing was recognized as an important tool to describe the process of normal swallowing and also to identify abnormal structures (anatomy) and functions (physiology). Initially, cine-fluoroscopy (recording of images on movie film) was used, but that procedure was abandoned in favor of video-fluoroscopy, since the latter offered the possibility of voice-over recordings, easier playback and transfer capabilities and reduced radiation exposure to the patient.

What is Dysphagia?

Difficulty swallowing, a medical diagnosis called dysphagia (“dis fay ja” or “dis fa ja”) can occur across the lifespan and may be due to a variety of neurological, structural/anatomical, infectious, iatrogenic, or even psychogenic processes (Palmer et al, 2000). In pediatric populations, dysphagia may present in babies who are born prematurely: who have genetic syndromes, maxillofacial deformities, and who have mental retardation or Down’s Syndrome. In youth and young adult life, dysphagia may occur secondary to multiple system trauma or medical conditions which require long periods of endotracheal intubation or placement of a tracheotomy. As people age, dysphagia may occur as a result of cerebrovascular accident (CVA) or of degenerative neurologic diseases such as Parkinson’s Disease, Amyotrophic Lateral Sclerosis (ALS), Multiple Sclerosis (MS), and Alzheimer’s Disease. In the same population, dysphagia can occur secondary to esophageal and gastrointestinal tract abnormalities such as Zenker’s diverticulum’s, esophageal strictures, esophageal dysmotility, and even hiatal hernia. Dysphagia may also be acute or chronic in terms of onset. Most causes of acute dysphagia include stroke-especially brainstem strokes, head or neck trauma, recent history of endotracheal intubation, burn, infectious disease, or allergic reaction. Chronic dysphagia may be associated with conditions such as Alzheimer’s disease, Cerebral Palsy, multi-infarct dementia, developmental delay, Down’s Syndrome, or neurodegenerative diseases such as ALS, Huntington’s disease, and MS.

Dysphagia may create a host of immediately threatening and chronic squeal in an individual. Most concerning is the phenomenon of prandial aspiration (hence referred to simply as aspiration), in which food or fluids enter the normally protected linings of the trachea and lungs. If an aspirated food particle is especially large, such as an under-chewed piece of hot dog, the potential for immediate and life threatening complete obstruction of the airway exists. If other food materials are aspirated, such as fluids or small food particles, the concern is not so much about complete obstruction of the airway, but rather infection that happens due to the foreign particles and the bacteria that accompany them.

Other less emergent consequences of dysphagia include weight loss, dehydration, malnutrition, failure to thrive, and social withdrawal. All of which have a negative impact on a person quality of life, which is an extremely important issue for the aging population.

Anatomical Landmarks, Functions of the Larynx, and Normal Swallowing

The larynx is the structure that houses the vocal cords. It sits at the top of the trachea or windpipe, and its primary biological function is to protect the airway and lungs from entry of foreign material. The upper throat area, known as the pharynx, is described as a shared passage way, meaning that it serves two principal functions—first as an extension of trachea for the purposes of respiration (exchange of O2 and CO2 during breathing) and second as a conduit for food and fluids during swallowing.

Normal swallowing depends upon intact anatomical structures as well as intact afferent and efferent nerve conduits, and the correct physiological function and coordination of numerous muscle groups and cranial nerves. The structures involved in swallowing are illustrated on the lateral views of the head and neck.

The structures include the teeth or dentures, the lips and intra-oral mucosa, the hard and soft palates, the velum, and the tongue blade—these structures comprise the oropharynx. In addition, the tongue base, the pharynx, the epiglottis and intrinsic larynx, and the upper esophageal sphincter (UES) comprise the hypopharynx. Within the hypopharynx are two sets of pockets or recesses known as the valleculae (plural of vallecula)—the pockets between the base of the tongue and the epiglottis and the pyriform sinuses, another pair of recesses that are adjacent laterally to the larynx and which in normal swallowing empty their contents into the UES as the swallow occurs. These recesses provide a convenient physiologic “catch basin” for any food or fluid that should accidentally enter the hypopharynx prematurely before the swallow reflex occurs, thus helping ensure the spilled material stays out of the airway. Such premature spillage occurs frequently in dysphagic patients but also occurs in normally healthy adults who might be eating rapidly in the context of doing another distracting activity. The same recesses do pose problems for dysphagic individuals because with incomplete swallows, there frequently is residual material remaining in the recesses after the swallow. This pooled residual material can then compromise the airway at any time up to and including the next, subsequent swallow. This occurs because the airway is “open” for the exchange of oxygen more than 95% of time, except for the actual times that we swallow, phonate, or hold our breath.

The larynx includes three integral “layers” of protection which work in synchrony during swallowing to ensure that the airway is protected from invasion of foreign material—in this case, food or fluid. These layers include—in order of activation—the medialization and compression of the “false” or aryepiglottic vocal folds, the inversion of the epiglottis as the larynx elevates, and, lastly, closure of the true vocal cords at the height of the swallow. Please examine the following illustrations of anatomy of the swallowing process and pharyngeal recesses.

People swallow for two reasons—first as a “housekeeping” or maintenance behavior that allows them to manage oral secretions such as saliva or nasal drainage. This type of swallowing occurs continuously both during the day and at night, when people are awake and when they sleep. For the most part, this type of swallowing is reflexive and happens subconsciously, but just like swallowing food, it can be willfully initiated (say, if you feel a “lump” in your throat or have an excess amount of saliva). The process of normal swallowing, thus, is a highly complex, dynamic activity that is dependent on both conscious, volitional cortical action (i.e. the processes of chewing and or manipulating food in the oral cavity and initiating the swallow) and largely reflexive, subcortical neuromuscular patterns (the squeezing of pharyngeal constrictor muscles and movement of the food through the back of the throat). Normal, safe swallowing of per oral (p.o.) nutrition (i.e. food taken by mouth) requires that an individual be awake and cognizant of the presence of food or fluid in the mouth and the need to swallow. This isn’t a problem for most adults, but for severely handicapped or disabled patients, their degree of wakefulness or awareness of the need to swallow once food is in their mouth can limit their ability to get adequate nutrition or protect their airway during swallowing.

Normal swallowing is usually a rapid, almost instantaneous activity. However, for purposes of illustration, it is helpful--somewhat artificially--to break the phases down into many steps in order to comprehend what the SLP and Radiologist are evaluating during the MBSS.

The Oral Preparatory Phase

This initial phase of swallowing describes the oral manipulations that happen prior to the actual intentional initiation of swallowing. In this phase, an individual opens his or her mouth to admit the portion of food or liquid, which we shall call a “bolus”, to be swallowed. If the item of food comes on a fork or spoon, the individual must position the tongue just under the utensil in order to receive the item of food. Then, the person must close his or her lips and teeth in order to “strip” the bolus off of the utensil. If the food item requires chewing, this is done. This is also the stage when the food is tasted or savored. At the close of this stage, the food item is brought together into sort of a ball, compressed, and held between the tongue and the hard palate. Completion of this stage requires good intra-oral (within the mouth) sensation, good function and range of motion of the tongue, and good strength and range of the jaw for chewing. If an individual has impaired sensation on one side such as with a stroke, he or she may not be aware of food collecting in the spaces between the teeth and lips and may “pocket” food on that impaired side, especially in the buccal sulci (the spaces between the teeth and the cheeks). Also, if the individual has reduced tongue control, she may not be able to contain liquids in her mouth, and the liquid thus pours “prematurely” off of the tongue into the back of the throat area (which we call the “pharynx”). When this happens, the fluid may be inadvertently aspirated.

Note that all the actions of the oral preparatory stage of swallowing are conscious and voluntary. All of the “actions” have thus far been limited to motions of the tongue, cheeks, lips, and jaw, and the food has been “prepared” in the forward 2/3 of the oral cavity (mouth). During this time, there is no swallow reflex and the airway remains open for the usual purposes of respiration.

The Oral Phase of Swallowing

Up until this point, the actions we have described in the Oral Preparatory Phase of Swallowing could be timeless—imagine how long, for example, a person could chew a single stick of gum, especially if she wanted to set a Guinness World Record. However, unlike chewing gum, most food is intended to be swallowed eventually—whether very rapidly, such as the person attempting to win a pie eating contest—or very slowly, such as a wine taster or someone savoring their favorite dish. The time that a person begins the conscious, voluntary activity of swallowing is known as the start of the Oral Phase of swallowing.

As the Oral Phase begins, the tongue starts to squeeze the bolus between the soft palate and itself. As such, a groove or channel becomes evident in the tongue, and its pressure ultimately conveys the food bolus posteriorly into the back of the mouth. As the bolus passes the posterior faucial arches, the actual swallow reflex occurs.

The Pharyngeal Phase of Swallowing

Suddenly, a very complex set of rapid muscular activities occurs. The soft palate or velum rises to close off the nasal cavity from the oral cavity so that food/fluid doesn’t run out the nose. The bolus is conveyed into the actual back of the throat, an area we call the hypopharynx , by the tongue squeezing against the muscular structure of the posterior pharyngeal wall. As this happens, the arytenoid cartilages in the larynx are brought to the midline and compress the false vocal folds tightly into the epiglottis. At this same time, strap muscles in the neck and under the jaw pull the larynx superiorly and anteriorly, elevating the airway (Van Daele, McColloch, Palmer, and Langmore, 2005). This has the next effect of inverting or retroflexing the epiglottis which forms a chute as it closes over the airway. Then the pharyngeal constrictor muscles compress the lateral pharyngeal walls into the midline in a peristaltic wave that moves the bolus into the UES, which relaxes and opens to accept the bolus into the esophagus as the larynx is pulled upward. At this point, with the food mostly safely in the esophagus, the larynx descends, the vocal cords abduct or open again.

The Esophageal Phase

Once the bolus enters the esophagus, it tends to slow down a little. All the actions since the start of the oral phase have been relatively rapid, taking about one second or less for the food to go from the tongue through the hypopharynx into the esophagus. It can take considerable longer for the food to be conveyed from the top of the esophagus into the stomach. As the food enters the esophagus, a series of peristaltic waves take over to basically “strip” slowly though the esophagus into the stomach.

Please examine various anatomical landmarks as viewed with fluoroscopy during this fairly normal exam. Here, you see a patient with very mild complaints of dysphagia. She is swallowing cup sips of liquid first, and finally, a solid cracker. Her epiglottis clings very tightly to the base of the tongue, so in this case the actual epiglottic inversion or retroflexion is difficult to see. In this exam, the patient is generally swallowing well, except that she has a very small amount of vallecular residual that has to be managed with a second “dry” swallow. However, she does not spill or loose material into the pharynx before the swallow, and her swallow is timely and rapid. This patient protects her airway adequately and has not aspirated or penetrated.

Abnormal Swallowing

It should be emphasized that normal, safe swallowing is dependent upon three things:

1. Intact oral and pharyngeal anatomical structures.
2. Accurate and timely muscular activity and coordination (i.e., tongue and pharynx squeezing, strap muscles elevating the larynx).
3. Intact sensory activity and feedback: (i.e. the sensory receptors located on the tongue and inside the mouth, sensory receptors at the entrance to the larynx and at the vocal cords).

Inadequacy of any of these components can lead to subjective complaints of difficulty swallowing. Aspiration is not the only “negative” sequelae from dysphagia. Even if someone manages to avoid aspiration while eating, the process may yet be effortful and uncomfortable. The consequence is that these individuals may take a great deal longer to consume a meal (have prolonged meal times), they may avoid certain desirable foods and may thus eat or drink less and lose weight, or they may feel self-conscious about their effortful swallowing and avoid eating in public or with family. Also, if someone aspirates with a cough and does so frequently, the coughing itself can be a deterrent to adequate nutrition. Swallowing can also sometimes be painful, such as with patients who have oral lesions, ulcers, or infections.

Usual Procedure

The Modified Barium Swallow Study is usually completed as a collaboration between the radiologist and a speech-language pathologist. The speech pathologist directs the order and sequence of food or liquid trials given during the exam as well as any treatment techniques or behavioral/postural changes. The radiologist operates the fluoroscopy equipment, verifies the presence or absence of aspiration, and often discusses the findings of the swallow study with the speech pathologist. Although regional variations do exist, often the speech-language pathologist will bear the primary responsibility for documenting the results of the study, conveying these results to other professionals involved in the patient’s care, and applying the information gained from the study in a practical way (for example, recommending a particular diet because of a study’s outcome).

Prior to the examination, the speech pathologist takes a thorough history from the patient. Often, this component of the exam is very revealing. Patients may complain of difficulty swallowing solids, liquids, or a combination of these. Sometimes, they have difficulty with only one type of food (for example, “particulate” foods such as rice, corn, or peas). They may complain of excessive phlegm production or the feeling that something is perennially “stuck” in the back of the throat—this is something we refer to as a “globus” sensation. Or, they may complain just of this feeling of obstruction right after they swallow. Sometimes, these complaints can persist even though patient’s swallowing may turn out to be normal—common etiologies for globus sensation include heartburn or gastroesophageal or laryngopharyngeal reflux disease (GERD/LPR), esophageal stricture, or post-nasal drip.

It’s also helpful to for the speech pathologist to document if the patient avoids any particular foods, if patient has had any recent changes in overall health, any history of respiratory infections, any changes to his or her smell, taste, or food intake, any problems with unplanned weight loss or dehydration, or if extended time is needed to consume a meal. The speech pathologist next inspects the patient’s oral cavity and other visible structures involved in swallowing, and examines the patient briefly for the presence abnormal speech or voice characteristics that might suggest a neurologic condition that could adversely impact swallowing. The speech pathologist observes carefully for signs of vocal hoarseness (which could suggest a vocal cord paralysis), dysarthria or slurred speech (which could suggest that patient had had a neurologic event or stroke), or difficulty the patient might have in voicing or managing his or her own saliva or secretions. If a patient presents with a chronically wet or gurgly voice, the patient may have difficulty protecting the airway adequately.

At this point, the patient is carefully positioned in the fluoroscopy equipment. In some facilities, C-arm equipment is used for the study. The C-arm device has the advantage of being able to accommodate physically larger and mobility-challenged patients, as often times patients are able to remain in their wheelchairs (however, their shoulders and head/neck must rise above the wheelchair frame). It is important for patients to be positioned upright as comfortably as possible. Although it is technically possible for someone to swallow while lying supine or even while hanging upside down, these two positions are not considered ideal. Many facilities use a wheeled, narrow tilting chair that has the advantage of being narrow enough to fit within the equipment. This chair serves to support the patient’s head and neck for optimal positioning—it is especially important for evaluating patients who have difficulty with postural control or who are non-ambulatory. Ambulatory patients may be asked to sit on a stool, a platform, or they may stand for the examination. If necessary, patients are administered supplemental oxygen via nasal canula and saturations or other vitals can be monitored by a nurse.

Facilities have different protocols regarding the actual administration of the examinations. In most facilities, the speech language pathologist suggests the ordering of the test swallows and any trial treatment strategies, contingent upon the radiologist’s approval. Usually, the speech pathologist will feed the test swallows to the patient, but some facilities use radiology technologist or nursing assistants to do the feeding. Ambulatory patients are also usually able to feed themselves, whereas extremely weak patients or patients with hemiplegia or paralysis usually cannot. Most often, the doctor and the speech pathologist will view the images live “in real time”—however, due to the complex and rapid sequences of swallowing, the images are usually videotaped or even, now, captured digitally for later review and possible slow motion or frame by frame replay.

Although the modified barium swallow study is time-limited in order to reduce radiation exposure for the patient, the speech pathologist who performs the study will want to try a representative sample of p.o. textures and consistencies in order to reach valid conclusions about the state of a patient’s swallowing. Usually, a chewable food item such as cracker or cookie is selected, along with a pureed or pudding like texture and different thicknesses of liquids. Thickening of a patient’s liquids is one of the most common treatments or adaptations for patients with dysphagia. As such, thickened liquids are routinely trialed during modified barium swallow studies, especially if a patient demonstrates difficulty with thin liquids. Most clinicians identify different degrees of thickness or viscosity: regular or unthickened (nothing added); NECTAR-like or nectar-thick; HONEY-like or thick; and PUDDING-like, or thick.

Most clinicians also trial different bolus sizes, because a bolus’ size can affect how well it is swallowed. Usually, a distinction is made between teaspoon amounts versus larger quantities such as a sip from a cup or a large bite from a cracker. In some facilities, optional textures include a mixed, “cold cereal” like texture, a soft chewable item such as banana, a sampling of the food items a patient complains are the most difficult—even nuts or popcorn, or a barium tablet or gel cap. All trial food or liquid items are mixed with an appropriate amount of either powdered, paste or liquid barium contrast. Some facilities use a special formulation of barium known as Vari-Bar, which the manufacturer states yields a more reliable study because it is less likely to coat the structures of the hypopharynx.

Some speech pathologists follow a consistent protocol with regard to the ordering of test swallows, always administering the same items is a predictable order. Other clinicians modify the protocol to the needs of or on the basis of their knowledge of the patient. If the patient is an ambulatory, healthy adult, virtually any test food item could be given first. However, if the patient is frail and ill, the therapist might want to start with the food item that would be least likely to be aspirated, which for many clinicians is a pureed or mashed potatoes consistency. While the overall goal of the examination is to obtain a valid and reliable indication of the patient’s swallowing ability, the radiologist and the speech pathologist want to minimize any harm to the patient that could be caused by aspiration of the barium contrast. Thus, many radiologists will terminate the exam prematurely if the patient demonstrates a gross amount of aspiration, or if the patient clearly has no reflexive swallow or visible response to oral stimulation with food.

The following video shows a gross amount of aspiration in a patient who had suffered a large stroke:

In this case, the patient aspirates before the swallow even happens. This patient has poor control of liquid on his tongue. Note how as the patient takes a sip, the liquid pours over the base of his tongue into the valleculae and then overflows right into the larynx. Unfortunately, his shoulders obscure the image significantly, but the aspirated liquid can be seen in the anterior trachea on subsequent swallows as the patient’s larynx elevates during the swallow. Note that this patient did not cough or have any visible reaction to this large amount of aspiration. Also note how even after this patient swallows, there is still residue remaining in the pyriform sinuses and valleculae. This patient has a severe dysphagia, and has not been able to resume eating by mouth safely.

Most clinicians and radiologists start with imaging the patient in the lateral plane—this allows easy and ready identification of the key anatomical landmarks and gives the most comprehensive view of the barium contrast as it pass through the oropharynx. In order to minimize radiation exposure, most radiologists will obtain an initial image to check positioning of the patient and then wait until the patient has been given the first test swallow by mouth before turning on the equipment for video recording. Some radiologists will even synchronize the on/off of the equipment with the therapist’s commands to swallow. This is usually a good practice—however, some patients with dyphagia have impaired tongue sensation and mobility. Thus, they cannot get a proper sense of the location of the food to be swallowed in the mouth, and they may loose control of or spill the material into the hypopharynx well before they even begin to start the voluntary, deliberate phase of swallowing. When this occurs, it is called premature spillage off the tongue. If when the radiologist turns on the fluoroscopy equipment and contrast is evident in the valleculae and pyriform sinuses, premature spillage is often to blame. A related phenomenon occurs when contrast spills to the pharyngeal recesses before the swallow occurs secondary to delayed onset or trigger of the swallow reflex. In this case, contrast is again evident in the valleculae and pyriform sinuses prior to the actual swallow happening. A simple test during the procedure will illustrate the cause of the premature spillage: the patient is instructed to hold a bolus of liquid barium at the back of his or her mouth for several seconds. If the liquid spills to the recesses immediately during this time, then the spillage is secondary to inadequate lingual control or sensation. If no spillage occurs during these few seconds, then lingual control is judged to be fair to good. At this point the clinician instructs the patient to “Swallow now!” if contrast spills then and no reflex occurs immediately, the spillage is due to delay in the triggering of the reflex.

If pooling or residual contrast is seen in the hypopharyngeal recesses (known as the valleculae and pyriform sinuses), many radiologists and speech pathologists will perform an anterior-to-posterior (A-P) viewing. The patient will be rotated in the equipment 90 degrees in order to obtain an A-P view. This allows the team to see if the pooling or residual is bilateral or equally distributed, or if it occurs on just one side. Often this latter condition occurs when a patient has hemiplegia secondary to a Cerebral Vascular Accident (CVA).

A general rule of thumb is that the patient should generate a swallow within a second of being asked to. If the swallow does not trigger in this time, the food or liquid most likely has already spilled prematurely into the hypopharynx. Note that the airway remains open until the actual swallow trigger occurs, so any material that entered the hypopharynx prematurely may potentially be aspirated. A protective reflex called the LAR (laryngeal adductory reflex) will trigger in normal patients if spilled material touches sensory receptors at the rim of the laryngeal vestibule. This reflex promotes an immediate airway closure followed by a swallow.

The purpose of doing a MBSS is not only to identify oropharyngeal dysphagia, but also to examine a patient’s response to treatment strategies. Treatment strategies fall under three broad categories: dietary manipulations/adaptations, active strategies, and postural changes. With dietary manipulations, textures that the patient appears to swallow in the best or safest way are emphasized—while textures that seem the most problematic are avoided. For example, if a patient who has difficulty manipulating and chewing the cracker and swallows only a portion of it at a time, the speech pathologist might recommend avoiding so called regular texture foods, substituting softer, moister, less chewable foods instead. Alternately, if a patient shows aspiration with thin liquids but not thickened liquids or solids, the clinician might recommend switching to thickened liquids. With active strategies, a patient may be asked to hold his or her breath immediately before swallowing, so as to make the swallow more effortful and increase the neuromuscular effort. Sometimes, active strategies include simply limiting the size of the bolus the patient swallows, or alternating from solid boluses to liquid boluses. Lastly, with postural modifications, the patient may be asked to “tuck your chin.” In this strategy, the airway is drawn under the base of the tongue, which acts somewhat like an umbrella to shield it from spilled liquids or food. Or, patients may be asked to turn their head either to the left or right. With a unilateral stroke, weakness will sometimes manifest in the pharyngeal constrictors on the affected side. Patients may thus have pharyngeal pooling or residual only on that one side. Sometimes, having the patient turn his or her head to the affected side will help eliminate that pooling by compressing or closing off the recesses.

Dysphagia is an inherently heterogeneous condition, and patients who have dysphagia and aspiration may have wildly different behavioral patterns. Some patients may aspirate a small amount of many different consistencies, essentially a small amount of anything they eat. Other patients may aspirate a large amount, but only on one consistency—liquids, for example. Patients who demonstrate either a large quantity of aspiration on a single consistency or aspiration across consistencies may not be judged safe to take oral nutrition. For these patients, alternative forms of nutrition and hydration, such as a nasal or gastric feeding tube, may be recommended.

A procedure or examination such as the MBSS is often evaluated in terms of two terms: validity and reliability. A procedure is valid if it indeed measures what it is intended to measure. A procedure is reliable if it achieves the same result time after time. Research has shown that the MBSS is indeed a reasonably sensitive examination—meaning that patients who indeed have oropharyngeal dysphagia, particularly where aspiration occurs frequently, will be shown to have this after the MBSS is complete. One limitation on sensitivity is that the MBSS is time-limited—so patients who exhibit fatigue in swallowing may be under-diagnosed, unless the examiner has the forethought to test the patient at the conclusion of a meal. The MBSS has also been shown to be reasonably valid and reliable, although actual inter-rater reliability (consistency among examiners) has been shown to be sub-optimal (Wilcox, Liss, and Siegel, 1996). Many writers have argued that standardizing swallowing curricula in graduate school speech pathology programs and by adopting consistent exam protocols may be helpful in terms of improving the inter-rater reliability of clinicians performing MBSS exams.

The MBSS is also important in terms of ruling out dysphagia in patients with generic swallowing complaints. Sometimes, patients will offer complaints that appear to be related to swallowing, but in fact are not. Some symptoms of laryngopharyngeal or gastroesophageal reflux disease (LPR/GERD) include the presence of a globus sensation or “lump in the throat— this may be independent of the actual sensation of heartburn, which is highly suggestive of GERD. These patients may complain of sudden, paroxysmal choking events, “I choke on my own saliva”, but upon further questioning, it is revealed these events often don’t always correspond to actual ingestion of food/fluids. Often these patients will have normal swallows when viewed with videofluoroscopy. Similarly, normal swallows are sometimes found in patients who malinger, who have an exacerbation of laryngitis, who have psychogenic or psychiatric illnesses, or who have excessive muscle tension in the head and neck.

Although the modified barium swallow study is widely considered the “gold standard” examination for oral and pharyngeal dysphagia, a newer, complimentary instrumental endoscopic examination called FEES (Fiberoptic Endoscopic Evaluation of Swallowing) has been gaining acceptance and may soon be performed competitively with the MBSS (Langmore, 2006). In FEES, a flexible endoscope is passed though the patient’s nostril so that the larynx is viewed directly from above. Then, the patient is administered food or liquids mixed with food coloring. The patient’s anatomy and any aspiration or pharyngeal residue is the viewed before or after the swallow. At the time the swallow reflex triggers, the epiglottic inversion and laryngeal elevation promotes a fleeting phenomenon known as “white out”, when nothing can be seen. FEES has the advantages of being free from radiation, so studies using FEES are able to be sustained for longer time intervals—in this way, clinicians can more easily tell if a patient is impacted by fatigue. Because of its lack of time limitation, FEES is not only appropriate diagnostically but also therapeutically. FEES can be done every treatment session, if needed, in order to give the patient visual feedback about the success or failure of swallowing. FEES equipment is generally more portable than fluoroscopy equipment, so the FEES exam is able to be given at bedside with medically complex patients who otherwise might not tolerate a trip to radiology. A disadvantage of FEES is that aspiration may not be noted as reliably, since the white out phenomenon at the height of the swallow reflex is often when aspiration occurs. However, if someone aspirates during a FEES exam, the aspirated food is often easily viewable after whiteout, as it tends to collect on a part of the trachea called the tracheal shelf.

The MBSS exam is sometimes confused with an esophagram, especially since the two procedures often share the words “barium swallow.” The MBSS is designed to provide motion-captured images of food and fluid as it traverses the oropharynx and the hyopharynx. It is not designed or intended to provide views of the esophagus or interpretation about the state of the patient’s esophageal functioning, although if esophageal obstruction is suspected, some radiologists choose to perform screening esophagrams in the course of doing the MBSS. These screening esophagrams may reveal presbyesophagus or dysmotility conditions or suggest the presence of diverticuli, strictures, or achalasia. Not all radiologists perform these screenings, as the two exams, MBSS and esophagram, have different indications as well as different preparation requirements.

After the modified barium swallow study has been completed, the radiologist and the speech pathologist usually confer briefly, reviewing each other’s summary of the results of the study. While both participants prepare reports, usually the speech pathologist conveys the results of the study in lay terminology to the patient and any accompanying family members. Some clinicians find it helpful to rewind the videotape and play the actual exam for the patient and family members to see. The speech pathologist may make a recommendation for patient to be seen for swallow therapy, including further education, instruction in exercises to improve swallowing, and clinical monitoring of actual meals. In addition, distribution of reports to the appropriate professionals ordering the examination is important.

Conclusion

The Modified Barium Swallow Study is a commonly performed, dynamic assessment of swallowing performed in the Radiology department. This test is done under the direction of a Speech-Language Pathologist with a Radiologist operating the video fluoroscopy equipment and providing a radiographic interpretation. Results of the study can be used to recommend appropriate and tolerable oral diets for patients with swallowing difficulties. They can also be used to gauge interval improvement or worsening of swallow function. When necessary, the results can suggest that an individual no longer has the capacity to protect his or her airway when eating and as such, alternative nutritional means, such as tube feeding, may be indicated. The modified barium swallow study has proven clinical utility, and it will no doubt continue to be performed regularly for years to come.

Summary:

• The study of swallowing and swallowing disorders which includes the coordinated assessment and treatment of patients with swallowing disorders has evolved over the past thirty years.
• A primary reason that speech-language pathologists perform MBSS is they have the knowledge of the anatomy and physiology of the aerodigestive tract by virtue of their study of speech, language, and voice disorders.
• Dysphagia can occur across the lifespan and may be due to a variety of reasons such as:
  • Pediatric: genetic syndromes, maxillofacial deformities, mental retardation, or Down’s syndrome
  • Youth and young adult: multiple system trauma or medical conditions which require long periods of endotracheal intubation or placement of a tracheotomy
  • Adult and aging adult: cerebrovascular accident, Parkinson’s Disease, ALS, MS, Alzheimer’s Disease, Zenker’s diverticulum’s, esophageal strictures, esophageal dysmotility, and even hiatal hernia
• Prandial aspiration is when food or fluids enter the normally protected linings of the trachea and lungs. If an aspirated food particle is especially large the potential for immediate and life threatening complete obstruction of the airway exists. If other food materials are aspirated the concern is not so much about complete obstruction of the airway, but rather infection that happens due to the foreign particles and the bacteria that accompany them.
• The upper throat area, known as the pharynx, is described as a shared passage way meaning that it serves two principal functions—first as an extension of trachea for the purposes of respiration (exchange of O2 and CO2 during breathing) and second as a conduit for food and fluids during swallowing.
• Within the hypopharynx are two sets of pockets or recesses known as the valleculae (plural of vallecula)—the pockets between the base of the tongue and the epiglottis and the pyriform sinuses, another pair of recesses that are adjacent laterally to the larynx and which in normal swallowing empty their contents into the UES as the swallow occurs.
• These recesses provide a convenient physiologic “catch basin” for any food or fluid that should accidentally enter the hypopharynx prematurely before the swallow reflex occurs, thus helping ensure the spilled material stays out of the airway.
• People swallow for two reasons—first as a “housekeeping” or maintenance behavior that allows them to manage oral secretions such as saliva or nasal drainage. This type of swallowing occurs continuously both during the day and at night, when people are awake and when they sleep. For the most part, this type of swallowing is reflexive and happens subconsciously, but just like swallowing food, it can be willfully initiated (say, if you feel a “lump” in your throat or have an excess amount of saliva).
• The initial phase of swallowing describes the oral manipulations that happen prior to the actual intentional initiation of swallowing. In this phase, an individual opens his or her mouth to admit the portion of food or liquid, which we shall call a “bolus”, to be swallowed. Completion of this stage requires good intra-oral (within the mouth) sensation, good function and range of motion of the tongue, and good strength and range of the jaw for chewing.
• During the oral manipulation phase when the item of food comes on a fork or spoon, the individual must position the tongue just under the utensil in order to receive the item of food. Then, the person must close his or her lips and teeth in order to “strip” the bolus off of the utensil. If the food item requires chewing, this is done. This is also the stage when the food is tasted or savored. At the close of this stage, the food item is brought together into sort of a ball, compressed, and held between the tongue and the hard palate.
• During the pharyngeal phase of swallowing the tongue squeezes the food against the posterior pharyngeal wall, the larynx and airway elevate, the epiglottis retroflexes (inverts), the UES opens.
• With respect to the oral and pharyngeal phases, the esophageal phase is longer in duration than the oral and pharyngeal phases.
• Aspiration is not the only “negative” sequelae from dysphagia. Even if someone manages to avoid aspiration while eating, the process may yet be effortful and uncomfortable. The consequence is that these individuals may have prolonged meal times, avoid certain desirable foods and may thus eat or drink less and lose weight, or feel self-conscious about their effortful swallowing and avoid eating in public or with family. Also, if someone aspirates with a cough and does so frequently, the coughing itself can be a deterrent to adequate nutrition. Swallowing can also sometimes be painful, such as with patients who have oral lesions, ulcers, or infections.
• The Modified Barium Swallow Study is usually completed as a collaboration between the radiologist and a speech-language pathologist, but the speech-language pathologist bears the primary responsibility for documenting the results of the study, conveying these results to other professionals involved in the patient’s care, and applying the information gained from the study in a practical way.
• The speech pathologist takes a thorough history from the patient. Often, this component of the exam is very revealing. Patients may complain of difficulty swallowing solids, liquids, or a combination of these. Sometimes, they have difficulty with only one type of food. They may complain of excessive phlegm production or the feeling that something is perennially “stuck” in the back of the throat—this is something we refer to as a “globus” sensation. Or, they may complain just of this feeling of obstruction right after they swallow. It’s also helpful to for the speech pathologist to document if the patient avoids any particular foods, if patient has had any recent changes in overall health, any history of respiratory infections, any changes to his or her smell, taste, or food intake, any problems with unplanned weight loss or dehydration, or if extended time is needed to consume a meal.
• The speech pathologist inspects the patient’s oral cavity and other visible structures involved in swallowing, and examine the patient briefly for the presence abnormal speech or voice characteristics that might suggest a neurologic condition that could adversely impact swallowing. Vocal hoarseness could suggest a vocal cord paralysis, dysarthria or slurred speech could suggest that patient had had a neurologic event or stroke, chronically wet or “gurgly” voice may indicate that the patient is have difficulty protecting the airway adequately, or difficulty the patient might have in voicing or managing his or her own saliva or secretions.
• In some facilities, C-arm equipment is used for the MBSS instead of the traditional fluoroscopic equipment. The C-arm device has the advantage of being able to accommodate physically larger and mobility-challenged patients. Many facilities use a wheeled, narrow tilting chair that has the advantage of being narrow enough to fit within the equipment. This chair serves to support the patient’s head and neck for optimal positioning—it is especially important for evaluating patients who have difficulty with postural control or who are non-ambulatory.
• The speech pathologist who performs the study will want to try a representative sample of p.o. textures and consistencies in order to reach valid conclusions about the state of a patient’s swallowing. . Usually, a chewable food item such as cracker or cookie is selected, along with a pureed or pudding like texture and different thicknesses of liquids.
• The purpose of doing a MBSS is not only to identify oropharyngeal dysphagia, but also to examine a patient’s response to treatment strategies. Treatment strategies fall under three broad categories: dietary manipulations/adaptations, active strategies, and postural changes. A patient may be asked to hold his or her breath immediately before swallowing, so as to make the swallow more effortful and increase the neuromuscular effort. Simply limiting the size of the bolus the patient swallows, or alternating from solid boluses to liquid boluses. Lastly, with postural modifications, the patient may be asked to “tuck your chin”, which causes the airway to be drawn under the base of the tongue, which acts somewhat like an umbrella to shield it from spilled liquids or food. The patients may be asked to turn their head either to the left or right because with a unilateral stroke, weakness will sometimes manifest in the pharyngeal constrictors on the affected side. Patients may thus have pharyngeal pooling or residual only on that one side and turning his or her head to the affected side will help eliminate that pooling by compressing or closing off the recesses.
• Some speech pathologists follow a consistent protocol with regard to the ordering of test swallows, always administering the same items is a predictable order. Other clinicians modify the protocol to the needs of or on the basis of their knowledge of the patient. While the overall goal of the examination is to obtain a valid and reliable indication of the patient’s swallowing ability, the radiologist and the speech pathologist want to minimize any harm to the patient that could be caused by aspiration of the barium contrast. Thus, many radiologists will terminate the exam prematurely if the patient demonstrates a gross amount of aspiration, or if the patient clearly has no reflexive swallow or visible response to oral stimulation with food.
• The phenomenon of premature spillage, in which food or liquid boluses spill and enter the hypopharynx prematurely before the initiation of the swallow may be due to impaired sensation and control of the tongue or delayed initiation of the swallowing reflex.
• An indication for performing an A-P viewing during the MBSS exam is the presence of residual contrast or pooling in the hyopharyngeal recesses known as the valleculae and pyriform sinuses. This allows the team to see if the pooling or residual is bilateral or equally distributed, or if it occurs on just one side.
• A general rule of thumb is that the patient should generate a swallow within a second of being asked to. If the swallow does not trigger in this time, the food or liquid most likely has already spilled prematurely into the hypopharynx. A protective reflex called the LAR (laryngeal adductory reflex) will trigger in normal patients if spilled material touches sensory receptors at the rim of the laryngeal vestibule. This reflex promotes an immediate airway closure followed by a swallow.
• Some symptoms of laryngopharyngeal or gastroesophageal reflux disease (LPR/GERD) appear to be related to swallowing, but in fact are not and as a result often these patients will have normal swallows when viewed with video fluoroscopy. Normal swallows are sometimes found in patients who malinger, who have an exacerbation of laryngitis, who have psychogenic or psychiatric illnesses, or who have excessive muscle tension in the head and neck.
• Although the modified barium swallow study is widely considered the “gold standard” examination for oral and pharyngeal dysphagia, a newer, complimentary instrumental endoscopic examination called FEES (Fiberoptic Endoscopic Evaluation of Swallowing) has been gaining acceptance and may soon be performed competitively with the MBSS. FEES has the advantages of being free from radiation, so studies using FEES are able to be sustained for longer time intervals—in this way, clinicians can more easily tell if a patient is impacted by fatigue. A disadvantage of FEES is that aspiration may not be noted as reliably, since the white out phenomenon at the height of the swallow reflex is often when aspiration occurs.
• The Modified Barium Swallow Study is a commonly performed, dynamic assessment of swallowing performed in the Radiology department.
• This test is done under the direction of a Speech-Language Pathologist with a Radiologist operating the video fluoroscopy equipment and providing a radiographic interpretation.
• Usually the speech pathologist conveys the results of the study in lay terminology to the patient and any accompanying family members. Some clinicians find it helpful to rewind the videotape and play the actual exam for the patient and family members to see.
• Results of the study can be used to recommend appropriate and tolerable oral diets for patients with swallowing difficulties. They can also be used to gauge interval improvement or worsening of swallow function. When necessary, the results can suggest that an individual no longer has the capacity to protect his or her airway when eating and as such, alternative nutritional means, such as tube feeding, may be indicated.

References