Editor’s Note: This text is a transcript of the course, Back to Basics: Swallow Screening: How, when, and who, presented by Angela Mansolillo, MA, CCC-SLP, BCS-S.
After this course, readers will be able to:
- Describe how to assess available screening tools for validity, sensitivity and specificity
- List 2-3 appropriate screening tools for your setting, client population
- Identify potential roadblocks to comprehensive screening and describe strategies to facilitate implementation
Let’s start with some definitions to ensure we are on the same page with the terminology that is critical to understanding screening tools.
Let's first define an assessment. We typically want our assessment to be consistent with the World Health Organization (WHO) framework, which addresses three levels of assessment. You are probably familiar with this framework. The first level of the assessment is to identify and describe structures and functions. We look at those structures and functions that might be affecting swallowing, such as pharyngeal weakness, lingual weakness, vocal fold paralysis, or whatever those particular functional or structural issues might be.
Then we take our assessment to the next level by looking at the impact that those specific impairments might have on the individual's activities. In other words, that lingual weakness might mean that the patient is unable to chew and therefore needs a modified diet. However, we are not done with our assessment process.
We then want to take it to the third level, which is where we look at barriers to or facilitators of successful swallowing and participation; in other words, strengths and weaknesses. This is where we think about quality of life issues, and what this swallow impairment means for the person's ability to fulfill his roles and social responsibilities. If the structural impairment is lingual weakness, and the functional impairment is difficulty chewing and need for a modified diet, then the final level of that would be that this person is no longer able to go to the restaurant and socialize with his friends at their weekly breakfasts.
The WHO encourages us to look at all three levels as we move through our assessment process. For us, that means clinical or bedside evaluation and/or an instrumental assessment, such as fluoroscopic or endoscopic evaluation of swallowing. Another piece of that overall assessment process is a swallow screening, which is the focus of this course.
A swallow screening is not a full assessment, as you know. It is much quicker and easier to do. It is essentially a pass/fail procedure. There is no nuance here; you pass the screen or you do not pass the screen. We use it as a tool to identify those individuals who need a more thorough evaluation, or perhaps identify those folks who need to be referred to other professionals for other services.
This is part of the preferred practice pattern. A lot of information about swallow screening policies can be found on the ASHA website (www.asha.org/policy). It is very different from a full assessment.
Why do we bother with the screening piece of it? Why not just move on to a full assessment? We will look at some of the research around this question in a bit. But the studies have told us that the earlier we identify people who are potentially struggling with dysphagia – specifically, the aspiration component - the better they do. The earlier we identify the risk and get interventions going, the better these folks do over the long run. A screening allows for that early identification because a screening can be done whether or not the SLP is available.
Another reason for screening is that it allows for more accurate referrals for full assessment. In facilities that do not do screenings, referrals to speech pathology are made based on what the nurse thinks should be done or what the doctor thinks should be done, and whether or not they think we could contribute something useful. We do not necessarily want to be dependent on another individual's practice patterns. Screenings allow those referrals to be accomplished in a more objective way.
A third rationale for screenings is that they help us to identify patients who are at high risk of aspiration. When I say “we,” I am not just talking about speech pathologists; rather, I mean “we” as the healthcare team. Screenings help the nurse and the doctor on the floor, or the emergency room (ER) physician or ER nurse, identify those folks who are at high risk so that we can get supports and plans in place, regardless of whether or not the SLP is readily available.
Alternately, screenings help to facilitate return to oral feeding and oral medication. If the screen is being done in the emergency room at three o'clock in the morning, and the client passes the screen, he can then have the sandwich that he wants, or she can take the medications that the physician feels are important to get in. If the team waits for the SLP to come, it might be hours before the patient is able to get the medications or return to eating. If patients pass the screening, in other words, they are able to return to oral feeding and get their medications earlier. Overall, it is a more efficient way of approaching dysphagia in a healthcare setting. It helps to identify those at-risk people more quickly, and we do not have to put restrictions in place for longer than they need to be. And it gets us better referrals in the long run so that we can use the time we do have for assessment more efficiently.
Issues Resulting from Lack of Early Identification
There have been a number of studies that have looked at this idea of screening and associated outcomes. Those studies have demonstrated that without early identification of people with dysphagia in hospital settings, those folks are at higher risk for aspiration, higher risk for choking, and higher risk for dehydration and nutritional consequences. They are subsequently less able to participate in rehabilitation, either in that acute care setting or after moving on to an inpatient rehab setting or a skilled nursing facility (SNF)-level rehab. They do not do as well in rehab because we did not put those safety nets in place early on in the process.
The research that I have been referring to tells us that without screenings, without early identification of dysphagia, patients have longer hospital stays. They have higher mortality and higher pneumonia rates. It costs the hospital more, mostly due to those elevated pneumonia rates. There is a higher caregiver burden and lower likelihood of discharge to home.
One caveat is that the majority of these studies have been done with stroke patients. Those of you who work in acute care know that a few years ago, we had a mandate from the Joint Commission to have swallow screenings in place. That mandate no longer exists; the Joint Commission changed their mind about that. But at the time, there was a lot of research activity looking for a validated screening tool that would work for stroke patients, and in addition, that is where a lot of this other outcomes-related research came from as well. What are the outcomes when there is a screening process in place, and what happens when you do not put a screening process in place? That is why the majority of this research has been accomplished with patients who had strokes. There is evidence for the use of swallow screenings for other populations as well, and we will certainly look at.
We do not, unfortunately, have a lot of information around practice patterns. What are people actually doing? There is only one study (Macht et al, 2012) that I am aware of that looked at practice patterns, as related to patients in a critical care unit who were post-extubation. These were respiratory patients who had been intubated for ventilatory support and were now extubated. The researchers conducted a survey across a number of facilities to see how hospitals, specifically critical care units, were managing these post-extubation patients when it came to swallow screening. Back in 2012, less than half of the facilities were using a dysphagia screening tool with this population. In the majority of those that were using one, nursing staff was administering the screenings. In about a third, SLPs were administering the screenings. A small percentage had some combination. We do not have any research that is more recent than this study. I suspect that given all the research that we have now around supporting these post-extubation patients, there are probably more critical care units that are using a swallow screening tool. But we simply do not know much at this point about what tool they are using and who is administering it. Somebody out there should do a study!
Outcomes Associated with Screening
Here are some of the outcomes that have been associated with having screening protocols in place. Some studies have found lower pneumonia rates in stroke patients. Sorensen and colleagues (2013) combined implementation of a screening tool with a comprehensive oral hygiene program, and they were able to reduce post-stroke pneumonia rates.
Not only do stroke patients serve as subjects in much of this research into swallow screenings, but they are at particular risk for pneumonia. There is a type of pneumonia called “stroke-associated pneumonia,” which may or may not be an aspiration pneumonia. But there is a constellation of things that happen as a patient is having a stroke and in those few days post-stroke. The changes that occur in their immune systems make them much more susceptible to pneumonia. In the first three to five days post-stroke (depending on which study you look at), patients are at very high risk for pneumonia, regardless of whether they have dysphagia. That is what that term “post-stroke pneumonia” or “stroke-associated pneumonia” is getting at. These may or may not be aspiration pneumonias.
Finally, in terms of outcomes when screenings are used, there is more efficient identification of patients who need instrumental assessment. That is related to what we were talking about earlier. If we can use more objective measures, we can get the right patients to the right place for evaluation.
What Makes a Good Screening Tool?
I have made the point that we need good screening tools. But how do you identify a good screening tool? First, a good screening tool should be easy and quick. Again, we are not talking about a full clinical assessment, and we are certainly not talking about instrumental assessment. A screening needs to be something very easy that does not take a lot of time. In many cases, it needs to be something that someone other than an SLP is able to do. It cannot be very costly, or administrators will not go for it; that is just a fact.
Validity. In addition, of course, we want a tool that is valid and reliable. If you can think back to your statistics class for a moment (without having post-traumatic stress!), you will recall that a test or tool is valid when it measures what it says it is going to measure. We want to make sure that whatever screening tool we choose actually does rule in and rule out aspiration, or rule in and rule out dysphagia, depending on what our goal is.
Reliability. We also want to be sure that any assessment tool is reliable. Reliability is about consistency. We need to be sure that regardless of whether Nurse A gives that screening or Nurse B gives that screening or SLP C gives it or Doctor D gives it, we will get the same results. The key to reliability in any assessment instrument is good instructions. People need to be able to follow the instructions. If the instructions are complicated, then it becomes difficult to ensure that everybody is doing it in the same way, and doing it the same way every time they do it. Reliability is consistency, and consistency comes from a tool that is easy to do, has easy instructions, and whose results are easy to interpret.
Sensitivity and specificity. Here are two more terms that we need to think about: we need to think about whether our screening tool has sensitivity and whether it has specificity. These are terms that people sometimes get confused.
Sensitivity is the likelihood that a clinical sign will be present given that the dysphagia is present. In other words, this is the way that the tool rules in the dysphagia; these are actual positives. Let’s say you were administering a screening tool and the patient coughed and thus failed the screening, so you did an instrumental assessment. If the assessment showed the cough was, in fact, related to aspiration or some degree of dysphagia, then that would be an actual positive that would allow us to rule in dysphagia.
On the other hand, we also have to make sure that any tool we choose has good specificity. This is the way that we rule out dysphagia. It is the likelihood that the diagnostic sign will be absent given that the dysphagia is absent. These are actual negatives. Specificity means that if you administered the screening tool and there was no cough or no change in vocal quality or whatever your clinical sign was, then there for sure was no aspiration or no dysphagia (depending on what your tool was purporting to measure). In other words, this is the way that we rule out dysphagia, and say that a patient has passed the screening and does not need further assessment. This is really critical as we think about dysphagia management because of the risk of silent aspiration. We need to be sure that whatever tool we are using has the ability to truly rule out dysphagia in a way that is accurate.
Ideally, a good screening tool has both good sensitivity and good specificity. You will see a lot of variability in those measures as we start to look at specific tools and the research around them.
Types of Screening Tools
There are four different types of screening tools. One is based on symptom identification; another type is questionnaires administered to patients or self-reports that they fill out on their own; a third category is water screening tools that actually ask patients to do swallowing as part of the assessment, and a final type consists of methods to look at reflexive cough.
Choosing a Screening Tool
How do you know which one to choose? That will depend partly on the client population with whom you are working, and partly on your setting. Some of it will depend on who is going to be administering the screening; are you looking for a tool that SLPs will use, or for a tool that has been validated with nurses or physicians? Keep those considerations in mind as we start to look at individual tools, and then you can start to match up the tool with your particular needs.
Gugging Swallow Screen
The Gugging Swallow Screen is a tool that includes a number of “indirect measures.” The person administering the screening makes judgments about the patient's level of alertness, presence of drooling, and changes in vocal quality. The patient is asked to complete some saliva swallows, followed by swallowing different boluses - food, thin liquid, and thick liquid.
Think about the patient population you are working with. Are you looking for something that can be used in a critical care setting? Are you in a hospital? Are you in a skilled nursing facility? These questions will help you determine which of these tools might be the best one for you and your setting.
This tool has really good sensitivity (100%); in other words, it is very good at ruling in aspiration. The numbers are not quite as good for specificity (69%), so it is less accurate at ruling out. In order to test this tool, they did the swallow screen followed by instrumental assessment; in this case, fiberoptic endoscopic evaluation of swallowing (FEES). That is always a good thing to look for. You will see that some of these tools we will talk about did not compare themselves to instrumental assessment.
This tool has been validated internationally in a number of different languages, in a number of different countries. It is designed to be administered by a SLP; it has not been validated as a nursing tool. It is somewhat labor-intensive in that there are three different boluses and a number of indirect measures to keep track of. Therefore, it is a little bit more involved than some of the other quicker screening tools that we will review. But it has been modified recently to correlate to the new International Dysphagia Diet Standardization Initiative (IDDSI) diet recommendations, so that is certainly something to consider.
Bedside Aspiration Test
The bedside aspiration test is a water test that consists of giving a total of 50 milliliters (ml) of water, in 10ml amounts at a time. So, it is five small swallows, and not serial swallows. The water swallows are combined with pulse oximetry. The authors found that when the patient was having some difficulty with water, such as coughing or change in vocal quality, and that was combined with a decrease in oxygen saturation measured via pulse oximetry, they were able to predict aspiration with 100% accuracy. Specificity of the tool – that is, the ability to rule out aspiration - was around 70%.
This tool has only been validated with stroke patients. There is some new research related to pulse oximetry accuracy that we will look at shortly that may call some of this into question. But it is a fairly quick test to do. One of my concerns about it is that larger boluses and serial swallows are never tested, and in my experience, those measures have a lot of predictive ability.
Volume Viscosity Test
The Volume Viscosity Test (VVT) also looks at a number of different bolus types (water or thin liquid, nectar-thick, and pudding-thick) administered in three different volumes or bolus sizes (five, 10, and 20 milliliters). The authors validated their tool based on instrumental assessment, using fluoroscopic swallow study. They validated the tool in two ways, looking not only at its ability to rule in and rule out aspiration, but also to rule in and rule out pharyngeal residue. That is something we do not see very commonly in the other screening tools, so the VVT is unique in that regard. They looked at a number of patients with neurologically-based dysphagia, including not only stroke patients, but also patients with other types of brain injury as well. All of this is in the original work done in 2008.
In 2014, a different group of researchers combined the Volume Viscosity Test with the Eating Assessment Tool (EAT-10). If you are not familiar with the EAT-10, it is a questionnaire consisting of 10 questions that patients answer. When they combined the VVT with the EAT-10, they found sensitivity of 91% and specificity of 28% for aspiration for the VVT. In that second study, they did not look at residue; only at aspiration. Inter-rater reliability was not so great, at 62%, so that certainly is a little concerning.
Toronto Bedside Swallowing Screening Test (TOR-BSST©)
The TOR-BSST is a very well-studied tool. It includes water swallows and an assessment of vocal quality before and after. There is also an assessment of lingual mobility. This tool has been studied in acute care settings as well as in rehabilitation settings. It has fairly high test-retest reliability (92%) and good sensitivity (91.3%). Specificity is also good, though there is a bit of a difference depending on your setting (93.3% for acute care; 89.5% in rehab). One caveat is that this tool was studied only in patients post-stroke. One nice thing about it is that there is a training program included with the tool. It probably has such good reliability numbers because of that full training program for speech pathologists and nurses who are administering it.
Massey Bedside Swallow Screen
The Massey Bedside Swallow Screen includes an assessment of cough, gag, and saliva swallows. The screener is asked to make a judgment about whether or not dysarthria is present, and whether or not aphasia is present. There is a modified oral mechanism assessment that goes along with this. Then there are water swallows of a teaspoon, followed by a larger 60cc volume. This is designed to be a nurse-administered tool. It has good reliability, sensitivity, and specificity. However, a caveat is they didn't compare this to instrumental assessment; they compared it only to clinical signs of dysphagia. In my mind, that is problematic. In addition, the sample size was small (N=25). The Massey, like the TOR-BSST, is a screening tool for patients who have had a stroke.
Modified Mann Assessment of Swallowing Ability
You may be familiar with the Mann Assessment of Swallowing Ability (MASA), which is a 24-item standardized protocol for the clinical or bedside swallow evaluation. The Modified MASA uses just 12 of those items so that the tool can be administered more quickly. Those items include assessment of level of alertness, speech and language functions, oral mechanism examination, respiration, and cough. You do not administer boluses. The Modified MASA was also not compared to instrumental assessment; instead, it was compared to the full MASA, which has been compared to instrumental assessment in past studies. We could say that the Modified MASA has been indirectly compared to instrumental assessment, but not directly. The sensitivity (92.6%) and specificity (86.3%) numbers are not bad.
Emergency Physician Swallowing Screen
This is a tool that was very specifically developed for use in emergency rooms (ERs) by emergency physicians. It includes an assessment of vocal quality, facial asymmetry, and language skills. It also asks the patient questions about any swallow difficulties he or she might be having. That is followed by water swallow tests combined with pulse oximetry. This tool, too, was validated only with the post-stroke patient population and was not compared to instrumental assessment. It was instead compared to the follow-up formal clinical swallow evaluation that the SLP did. Sensitivity (96%) is pretty good. Specificity - the ability to rule out aspiration or dysphagia - is not so good. That is really something we have to think about in an emergency room setting. If you say, "Yes, you have passed the screen, and you can go ahead and have that sandwich or take those medications," you want to be sure that the patient truly is safe. With this tool, you might not be so sure about that.
Part of the problem, I think, was that the study was done in an emergency room, so they were not always able to control for the amount of time that elapsed between administration of the screen and the formal evaluation by the SLP. In an emergency room setting, clearly, that is difficult to control. Nonetheless, that lack of control is problematic when looking at the results because stroke patients in emergency rooms can look very different from hour to hour. In my opinion, in light of that, we have to interpret these results carefully.
Barnes Jewish Hospital Stroke Dysphagia Screen
Just as it sounds, this tool has been validated with patients who have sustained a stroke. It is a water test that administers 90ml of water, plus the Glasgow Coma Scale, which is an assessment of alertness. It also includes assessment of facial, lingual, and palatal asymmetry and strength. The authors did validate this tool against fluoroscopic swallow study. The tool’s ability to rule in aspiration was very high (95%), while the ability to rule out aspiration was not so high (50%). This tool was designed for use by nurses. Here is the link to the actual tool: https://www.tabletwise.com/calculators/barnes-jewish-hospital-stroke-dysphagia-screen.
Oral Pharyngeal and Clinical Swallowing Examination
This screening is an older one that goes back to 1997. It was validated with patients who have sustained a stroke. It includes an oral mechanism examination as well as water swallows in varying volumes of five, 10, and 20 ml, two times each. Laryngeal palpation is performed during the swallow and vocal quality is assessed after each swallow. The authors did study this tool in comparison to videofluoroscopic swallow study. They calculated sensitivity using all of the various clinical signs, and interestingly, they found that dysphonia and dysarthria were the most predictive of dysphagia severity. Whether or not you use this screening tool, it is important to keep in mind as you are doing your clinical assessment that those changes in voice and changes in speech actually have predictive ability for the presence of dysphagia and aspiration. In fact, when two or more clinical signs were present, the sensitivity - the ability to rule in aspiration -increased. Again, whether you think about using this tool or not, there is some really helpful information here as we proceed through our clinical evaluations.
Standardized Swallowing Assessment (SSA)
The SSA includes an assessment of level of alertness and posture, which is something we do not see very often in screening tools. It also assesses cough, saliva management, respiration, and vocal quality. It includes water swallows via teaspoon and cup sips. It is pretty quick and easy to do. It has been validated for use in hospitals, and the original research was done with nursing staff, so it may be appropriate for those of you in skilled nursing settings as well. In those settings, we are always looking for something that the nurses can do that will not take a lot of time. Sensitivity and specificity numbers looked good, but there was no instrumental assessment comparison used in the validation process. One of the interesting things about this tool is that the instructions include discontinuation of the screening if the patient does not have sufficient head control and postural stability to sit unsupported and participate. That is not something you see in most screening tools. If that factor is something of concern in your population, this may be an interesting one to look at.
Pulse oximetry was mentioned earlier. It is included in a couple of the screening tools we have looked at. There have been a number of studies that have tried to find a relationship between a drop in oxygen saturation, as measured on the pulse ox, and an aspiration event. It would be really nice if we could say definitively that when you aspirate, your oxygen saturation drops. Unfortunately, none of the studies were actually able to find that relationship. There were plenty of people who aspirated but did not have a corresponding drop in oxygen saturation. There were people who did experience drops in oxygen saturation that were not related to aspiration events.
I am not saying pulse oximetry does not tell us anything. It actually is a really nice way of getting a sense of the work of breathing. How is this person's respiratory system responding to the demands that repeated swallowing is placing on it? What about endurance for feeding? Pulse oximetry, the measurement of oxygen saturation, can give a lot of good information in that regard, and there is some work that we will look at that demonstrated that baseline oxygen saturation is an important number to pay attention to. If you have a patient who is being monitored for oxygen saturation, and you have the pulse ox right there, then absolutely, there is some good information we can obtain with it. But be careful not to over-interpret those drops in oxygen saturation. They do not necessarily mean that the patient has aspirated.
Respiratory factors associated with aspiration. Steele and Cichero (2014) reviewed all of the available literature on the respiratory factors we might see as we go through our screening process that would be predictive of aspiration. The ones that had the most evidence to support them are:
- Rapid respiratory rate (>25 bpm)
- Low baseline oxygen saturation (<94%)
- Inconsistent swallow-respiratory pattern
- Post-swallow inhalation
- Short swallow apnea duration
Before we go through these, I’d like to point out that none of the research in this particular review included pediatric subjects; they were all adult subjects.
What were the respiratory factors that were predictive of aspiration? One was a rapid respiratory rate (RR). When the respiratory rate is upwards of 25 breaths per minute or more, then there is increased likelihood that the patient is aspirating.
As previously mentioned, low baseline oxygen saturation is a risk factor. If you have a patient who has the pulse ox on, and is already down around 94% oxygen saturation before you have even started your screening or your swallow trials, then that patient really has nowhere to go but down once you start to impose the demands that swallowing places on the respiratory system. Remember, every time we swallow, we hold our breath. For those of us with normal respiratory systems, that is not a problem. But for people who are already compromised, and already have a low oxygen saturation, then there is nowhere for them to go but down when they start to experience repeated swallow apnea. The breathing-swallowing coordination is going to be impaired, and we are going to see a higher likelihood of aspiration.
This research also calls our attention to inconsistencies in the swallow-respiratory pattern, particularly a consistent post-swallow inhalatory pattern. That, and/or shorter-than-typical periods of respiratory pause during the swallow, increase the likelihood that the patient has aspirated or is aspirating.
Cough Reflex Testing
Here is some of the research around cough testing. The idea is to try to tap into the reflexive cough. Voluntary cough is different than reflexive cough. When I ask you to cough, that uses a different neural pathway than the neural pathway used when you cough reflexively to protect or clear the airway. All of this research has been trying to tap into that reflexive cough pattern, rather than voluntary cough, by using an irritant. The irritant used differs between different studies; some researchers have used tartaric acid, others used citric acid, and still others used capsaicin. The irritant was dissolved and nebulized, and the subjects in the study inhaled it. The researchers then watched to see if there was a cough response, and if so, how strong the cough response was. Then they would make predictions about whether or not patients were aspirating, and whether or not patients were able to protect their airways based on their cough response to the particular irritant.
The research is far from conclusive. There are a lot of variables because different researchers used different irritants and different concentrations of irritant. Even the ones that used the same irritant used different concentrations. As a general trend, we see cough testing tending to over-identify potential aspirators; in other words, people failed the cough test who were actually able to protect their airways.
I guess that the conclusion here is that we cannot draw a firm conclusion. Most of us do not have access to these irritants anyway in order to dissolve them, nebulize them, and administer them in the way that they were administered in the research studies. That is certainly one roadblock in terms of implementing this currently. I also worry about the over-identification of aspirators. We are still not at a point yet where we know which irritant is going to be most predictive and which concentration of that irritant is going to be most predictive.
The other big question in my mind as I look at this cough research is, are we sure that we are testing the right cough? We know that your voluntary cough is different than your reflexive cough. But is your cough in response to an irritant the same cough as if you were trying to keep something out of your airway? I am not convinced that it is. The research around cough says that it may not, in fact, be the same cough. Therefore, using an irritant may not be getting us where we want to go in terms of making predictions about whether or not people could protect their airway in response to aspiration. That may be where the over-identification of potential aspirators is coming from. I think that cough testing certainly has potential and we will be hearing more and more about it because cough is a hot topic in the research. Perhaps we will get to a place where we do have a tool that is easy to use and has good sensitivity and specificity.
3-Ounce Water Test
The 3-ounce water test is probably the best studied of all of the potential screening tools available. It was originally designed as a tool for assessing dysphagia in people with neurologically-based swallowing impairments. The patient is instructed to drink three ounces of water without stopping. If the patient coughs, or cannot finish, or cannot do it without stopping, or demonstrates a change in vocal quality during or following the administration of the water test, they are considered to have failed the screening. It did not really catch on when it was first described back in the early '90s, largely because it was proposed as a substitute for the clinical or bedside swallow evaluation. SLPs did not really love that idea. But then we received that mandate from the Joint Commission I talked about earlier to screen stroke patients before they had their first meal or their first meds in acute care settings. Everybody was looking for validated screening tools at that point, and the 3-ounce water test came back to our attention.
Doctors Leder and Suiter did amazing research on this 3-ounce water test. They studied 3,000 people, and not just stroke patients, but a wide variety of underlying etiologies of dysphagia. They compared the 3-ounce water test to instrumental assessment by following it up with FEES. They found that if you passed the water test - that is, if you could drink three ounces of water without stopping and without signs and symptoms of difficulty - then you were, in fact, not aspirating. That is important for a screening tool.
They did, however, find a high false positive rate. Personally, I am okay with that in a screening tool. If you come into the emergency room in my facility at three o'clock in the morning, and the nurse has some meds she has to administer, and the ER doctor or the nurse does a water test and you pass, we want to be sure that that means you are safe -- and it does. If you fail, and you have to wait for your medication or wait for the SLP to come in and determine if you are safe, I think that is acceptable in a screening. Leder, et al. did a study in 2011 to determine what types of people were having false positives. Who were the people who could not drink three ounces of water without some sign or symptom of aspiration, but were actually not aspirating on an instrumental assessment? It turns out they were folks who were deconditioned, who had impaired cognition, and/or who had low endurance. Those are appropriate referrals to a speech pathology service anyway, so if those are the false positives, then I am comfortable with that.
Suiter, et al. (2009) also did a smaller study with the same study design, using the 3-ounce water test with a pediatric population aged two to 18 years. The results were essentially the same. Across patient populations, across age groups, and across settings, the 3-ounce water test seems to be a good tool.
What about silent aspirators? The researchers were wondering about that, too, and set out to determine what was going on with those folks who were aspirating silently. They designed a study where every subject in the study was known to be a silent aspirator. As they identified patients who were silently aspirating on their instrumental assessments, they then did the 3-ounce water test with those individuals. They found that patients who were aspirating silently on single bites or single sips were not so silent when it came to drinking three ounces of water without stopping. When you increase the volume to three ounces and increase the demand to serial swallows that require a more prolonged period of breath-holding, you can actually identify those patients who would be silent aspirators if given smaller volumes with less respiratory demand.
Even if you are not necessarily in the market for a screening tool - although you probably are if you are taking this course - this is a good adjunct to your clinical assessment. If you want to walk out of that patient’s room and be sure that you have not missed silent aspiration, use the 3-ounce water test as part of your clinical assessment.
The Cognitive Assessment is from the same group of researchers from Yale that authored the 3-ounce water test. They essentially did a quick cognitive screen, checking orientation and ability to follow directions, and then followed that up with instrumental assessment. Again, they used a large number of subjects with a wide variety of diagnoses and wide age range. The youngest subject was 10, and the oldest was 105. They found that patients who were disoriented and/or unable to follow directions, were more likely to be aspirating when they did the instrumental assessment. Now, this does not prove causation; we are not saying that disorientation and auditory processing difficulties cause aspiration. But they are correlated, and we can say that those cognitive issues are often predictive of aspiration. That is important to keep in mind as you are thinking about a screening tool, or thinking about how this might apply to your own clinical assessment.
Oral Mechanism Examination
That same group of researchers did the same kind of study, this time with the oral mechanism examination followed by instrumental assessment, to see if there were specific components of the oral mech that had higher predictive ability when it came to aspiration. It turns out that two things - impaired lingual range of motion and facial asymmetry - were associated with increased risk of aspiration. As you are doing your oral mechanism examination, remember that those two things are going to have the highest predictive ability specific to aspiration.
Yale Swallow Screen
Our friends at Yale took all of their research around the water test, silent aspiration, oral-mech exam components, and cognitive screen components, and combined all of it into a tool called the Yale Swallow Screen. This screening includes orientation questions and ability to follow directions, assessment of lingual and labial range of motion and facial asymmetry, and the 3-once water test. It has been validated for use by both SLP and nurses. Again, it was validated with patients with a wide variety of etiologies and across age groups.
Water Swallow Screening
This screening is based on work done by Hye, et al. (2013) with patients with head and neck cancer. This, too, used a water test. The volumes administered increased from 2ml to 5ml to 10ml to 20 ml. The researchers assessed for change in vocal quality, and watched for cough or throat clear, then followed the screening with FEES. Their results showed that the screening’s sensitivity was 100% and specificity was 61% for aspiration, and sensitivity was 96% and specificity was 82% for dysphagia. Water tests seem to be, regardless of the one you choose, the best way to screen for aspiration or dysphagia.
Review of Water Screenings
Brodsky, et al. (2016) did a review of all of the research around water tests a few years ago. He found that larger volumes, that is, screening tools that involved serial swallows, were better at ruling out aspiration, and smaller volumes were better at ruling in aspiration. A good screening tool would probably allow you to use both. When the water test was combined with an assessment of vocal quality, that seemed to increase its accuracy.
Self-Reported Swallowing Assessments
The next category of screening tools are self-reported swallowing assessments. These are more likely to be diagnosis-specific. Most of them are either questionnaires or forms that patients fill out themselves. Let’s look at some examples.
DYMUS. The DYMUS is the Dysphagia in Multiple Sclerosis (MS) tool. It has been validated for people with MS. It has 10 questions about dysphagia with solids and dysphagia with liquids. It is been very well-studied and does seem to have a correlation to dysphagia severity.
EAT-10. I mentioned this one earlier because it has been studied in combination with the Volume Viscosity Test, but it has also been validated on its own. This is a quick, easy-to-understand, and easy-to-administer tool. It is available in a number of languages. It has been well-studied in a number of populations, and there is a pediatric version. Here is a link: https://www.nestlenutrition-institute.org/docs/default-source/global-dcoument-library/nutrition-tools/eat-10---english-interactive---final-01262018.pdf?sfvrsn=2
Sydney Swallow Questionnaire. This one is a little bit longer; it has 17 questions. Most of the questions, with the exception of one, ask patients to rate their symptoms on a visual analog scale. This is not disease-specific, so it can be used across a wide variety of etiologies. You can take a look at it to see if it works for your population; the link is: https://stgeorgeswallowcentre.org/sydney-swallow-questionnaire/
Swallowing Disturbance Questionnaire. This tool has 15 questions specific to swallow function. The original research was done with patients with Parkinson's disease, but there have been more recent studies with other populations, including persons with head and neck cancer, other neurological disorders, and gastrointestinal (GI) issues. They have correlated their results to instrumental assessment using FEES.
Swallowing Outcomes After Laryngectomy (SOAL). As you would imagine, this tool is validated for patients who are status post laryngectomy. It can be used with patients who are undergoing radiation and chemo, or surgical patients. Either way, there are 17 questions about functional eating. It has been validated against instrumental assessment, using videofluoroscopy. If this is your population, this is a good self-report tool to use.
Patient-Reported Outcome Screening for Community-Dwelling Older Adults. There has been some interest in trying to identify dysphagia in the aging population before the clinical symptoms are manifesting themselves; that is, pre-clinical dysphagia. This group of researchers (Madhavan, et al., 2018) developed a tool for community-dwelling adults that includes questions about reductions in physical function, changes in cognition, and increased effort with eating. These questions could perhaps help us to identify those folks who are not experiencing dysphagia per se currently, but who seem to be on that road, and whose skills are deteriorating. I think this is going to be a really important tool for physicians to include as part of their assessment of patients. If you are doing some community outreach or education, for example at health fairs or that type of thing, this would be a good tool.
When to Screen?
When do we screen? Early and often is what the research tells us, particularly when we are talking about patients who have suffered a stroke. Early screening, before 24 hours post-cerebrovascular accident (CVA), seems to be critical to better identification and reduction of pneumonia risk. In fact, the 2018 Stroke Guidelines from the American Heart Association (AHA) and American Stroke Association (ASA) tell us that we should be doing swallow screening early, and that it can be done not just by a speech pathologist, but could also be done by another trained healthcare professional.
Registered Nurse (RN)-Administered Screens
What about nursing screens? Hines, et al. (2016) did a review of all the outcomes associated with RN-administered screens and found some good results, including fewer chest infections and better, more appropriate referrals to SLPs. Nurses can and should be part of the screening process.
Implementation Challenges and Facilitators
There are some barriers to implementing nursing screenings; it is not always easy to do. Some factors that nurses report as issues that get in their way (Daniels, et al., 2013) are:
- Difficulty finding time for documentation screening results
- Difficulty recalling screening items
- Inconsistent administration of screening
- Inaccurate interpretation of screening results
What do we do about these barriers? The same article above set out to identify facilitators, or things that can help nurses do better screenings. Certainly, education tools, such as video training modules or similar, can help, as can good support from the administration. But to my mind, that middle bullet (“Processes to support screening administration”) is actually the thing that helps the most. The thing that made the biggest difference in my facility was when we had order sets and a specific swallow screen template built into the electronic medical record (EMR). That was a big facilitator in getting the screening done more consistently and getting the screening done more accurately.
In 2009, Poskus published some work about a specific hospital, Waterbury Hospital, which is a Certified Stroke Center. Some barriers were identified that got in their way when trying to get screenings done. Again, problems with documentation and problems with compliance were identified. They also noted some cultural differences (e.g., concerns regarding scope of practice) that you might need to address in your facility.
To pull this all together, as you are considering a tool for your facility, for your patient population, look at the directions for that tool. Look at how easy it is to administer. Do you feel like you could get good consistency with it? Does it have good sensitivity and specificity? Also, think about screening not just as a standalone tool that a speech pathologist does or a nurse does, but also think about some of these screening tools as things you could incorporate into your own clinical assessment, to make that assessment more accurate and more predictive.
Questions and Answers
When you were talking about the cough reflex testing and the irritants, am I correct that you said, "Not only is the irritant itself not standardized, in that they are trying several different ones, but they have not really standardized the concentration either"?
That is correct. Particularly with the citric acid, different studies used different concentrations, so we are not really sure yet what that magic number is.
A lot of the screeners that were discussed seemed to be developed for patients with CVA. Would you use those same ones in a home health or SNF setting? Or do you feel that there are others that are more appropriate or some more appropriate than others in certain settings?
I think that when you are talking about a population outside of the stroke population, outside of the hospital, probably the 3-ounce water test is the best one for those populations and those settings. It is the one that has been looked at most thoroughly outside of the stroke population, and it is pretty easy to administer.
Re: the water test, it looks like testing on that included children as young as two years. Do you know what method of liquid delivery they used? Or are those results accurate whether you use a bottle, straw, open cup, or sippy cup?
That is a good question. They did not use a bottle; they used an open cup or straw.
Mansolillo, A. (2020). Back to Basics: Swallow Screening: How, when, and who. SpeechPathology.com, Article 20351. Retrieved from www.speechpathology.com.