Diet Modification Without Complete Mastication Evaluation?

by Karen Sheffler, MS, CCC-SLP, BCS-S of SwallowStudy.com

Introduction

I remember encouraging my toddler to play with his food. We had our favorite games.

One was to close our eyes and guess what food we were chewing based on the sounds of the initial crunches and chew cycles.

Our second favorite was to count the number of chews that each type of raw vegetable needed before it was swallow ready. Anything to get a toddler to explore new foods and vegetables! Counting chews was easy and quantifiable.

 

Do you recall my blog called “No Dysphagia Diet Modification Without Standardization” and other blogs, IDDSI resources, and 7 IDDSI Updates related to the International Dysphagia Diet Standardization Initiative (IDDSI)? Well, now I need to ask:

How are speech-language pathologists (SLPs) evaluating food oral processing?

Our dysphagia curriculum in university may not have covered food science, food oral processing, or even how to perform a thorough-quantifiable mastication evaluation. Are we using only subjective observation or quantifiable/measurable data?

This blog is in gratitude for Dr. Maggie-Lee Huckabee & her colleagues’ research published in 2018, validating the Test of Mastication and Swallowing Solids (TOMASS). In order to extend the reach of this test, I have created a test form for use in the clinic. (TOMASS pdf form for the clinic)

It was further inspired by Dr. Maggie-Lee Huckabee’s recent discussion: “The Validation of the TOMASS” on Ed Bice’s Swallowing and Swallowing Disorders Journal Club’s Facebook Live webinar on July 9, 2020.

I also want to acknowledge the January 2020 article in DysphagiaCafe by Ed Bice, M.Ed., CCC-SLP and Angela Van-Sickle, Ph.D., CCC-SLP that has already nicely reviewed the complexities of mastication and solid food breakdown. See discussion of the neurology of chewing, bite force, dentition, the role of the tongue, the key addition of saliva to a bolus for easier swallowing, and more. For additional research on chewing and mastication evaluation, please see the comments section where Linda D’Onofrio generously shared a Dropbox link with readers. As that article eluded to, we (speech-language pathologists/SLPs) know that there is so much holistic and critical thinking that goes into our assessments of swallowing and our predictors of safety and efficiency, and one examination cannot encompass everything. Bice and Van-Sickle concluded with a brief discussion of the need for a more thorough mastication evaluation. They mentioned the validated TOMASS and stated:

“Although this test has some limitations, it is a good place to begin.”

 

Therefore, I would like to encourage further exploration of the topic of mastication evaluation here.

 

Typical Qualitative Mastication Evaluation

Typically, swallowing evaluations have been only qualitatively describing chewing, as well as the oral preparatory and oral stages of swallowing with the following types of jargon:

• decreased rotary chew
• up and down munching pattern versus a rotary chew
• decreased bolus manipulation and formation (bolus means the formed ball of food or the liquid that is in your mouth to be swallowed)
• decreased lingual lateralization to maintain cohesive bolus
• decreased bolus control
• loss of bolus to lateral sulci
• pocketing
• slow oral transit
• decreased anterior to posterior propulsion (as if we can even see that once the lips are closed!)
• amount of residue in oral cavity after the swallow

 

What does all that mean? Are these qualitative descriptions standardized across the profession?

 

Even the standardized Modified Barium Swallow Impairment Profile (MBSImp by Martin-Harris, et al., 2008) only has a qualitative rating scale to describe “bolus preparation and mastication,” noting:

• 0 = timely and efficient chewing and mashing versus
• 1 = slow-prolonged chewing/mashing with complete re-collection of the bolus,
• 2 = disorganized chewing/mashing with solid pieces of bolus unchewed, or
• 3 = minimal chewing/mashing with majority of bolus unchewed.

 

Diet Modifications Based on Evaluations

Additionally, based on these qualitative judgements, we may recommend changing people’s diets and/or altering how the foods and liquids are prepared and presented. Of course, SLPs customize recommendations to the individual, but do they always consider the potential ramifications of all this advice?

For examples,

• We may initially suggest that an individual should consume foods that are tender and/or easy to chew (e.g., Easy To Chew, Level 7 from IDDSI – see the example titled “Adults – Level 7 Easy to Chew” in IDDSI’s consumer/patient handouts on each diet in their Resources tab). However, this IDDSI Level includes items that do not reduce choking risk. Read on…
• We may recommend specifically softer foods that pass a fork pressure test. This means that a food piece will squash or deform with pressure from the fork. See Fork Pressure Test in links found on this IDDSI section of The IDDSI Framework and Testing Methods. We make many recommendations on what foods to avoid, such as hard, dry, crumbly, and sticky foods. We caution intake of breads and meats to reduce choking risks as needed, especially per IDDSI’s systematic literature review in 2015 that included coroner’s reports.
• We advise adding sauces to make foods moist, cohesive, and slippery (see the Spoon Tilt Test in the testing methods and IDDSI’s brief review of testing methods here). We also may advise to avoid mixed consistencies  (i.e., cold cereal with milk, juicy fruits, soups, etc), as people can aspirate on a liquid while trying to manage a solid in the same bite. We have people add oral moisturizer agents to compensate for dry mouth (link my saliva blog).
• To really reduce choking risk, we recommend smaller particle sizes. Cutting up foods into bite-sized pieces can significantly reduce choking risks (i.e., Soft & Bite-Sized, Level 6). This is the IDDSI diet level that has the particle size of 1.5cm cubed. That is the size that will fall through an airway and not block it to cause asphyxiation — See this demonstration on my Youtube video).
• Further diet texture modifications: We may alter the look of a person’s food even more with recommending that all foods are minced or ground down to the size that does not require much further chewing (i.e., Minced & Moist, Level 5). This IDDSI diet has particle sizes of 4mm by 15mm. That is the size of foods that have already been chewed and are swallow ready!  See detailed definitions and descriptions in IDDSI’s Framework section on their website, or in the complete Framework document in English).
• We may give the option of a Pureed, Level 4 diet. These foods are moist and blended smooth. The diet may be safer and temporary, especially after a new stroke or when a person is critically ill with minimal ability to chew and clear more challenging solid foods. However, not all purees are created equal; please see IDDSI’s 2020 article focusing on puree, as well as this blog about why someone may require a puree diet and how to make and test an ideal puree. Even pureed foods can cause choking if they do not follow specific guidelines.

Imagine, these examples above are simply a quick review of some of the potential diet modifications. I have not even mentioned all the postural techniques or safer swallowing strategies that SLPs may recommend!

It is easy to see how drastically altered the meal can become based on our assessments. We may be reducing the person’s sense of control and feeling of having options without realizing it.

Potential Rationales & Ramifications of Diet Modifications

With all these changes, SLPs know that we cannot prevent aspiration and choking risks 100% of the time, but we hope that we are helping the person with a swallowing problem (dysphagia) to:

• consume food, liquids and pills easier and safer;
• swallow more efficiently with less effort and/or fear;
• reduce pain or discomfort in the mouth, jaw, throat and esophagus;
• reduce fatigue with eating (aka, “time to task failure,” per Dr. Ferreira – stopping a meal/task early. Check out Dr. Leonardo Ferreira, MD’s discussion on Down The Hatch Podcast about “fatigue” and weakness);
• reduce pocketing and residue leftover in the mouth, throat, and/or esophagus;
• reduce the risks of aspiration on food particles and/or liquids;
• reduce the risks of choking on food boluses;
• prevent weight loss by easier caloric intake;
• continue to enjoy eating and have success at meals and snacks, and more.

 

However, the altered diets may affect the quantity of intake (refusals due to appearance and diet restrictions) and the quality of life. There are ramifications to making these diet texture modification recommendations. The impact is all the more profound when we consider that these recommendations may be based on subjective or qualitative assessments only.

 

Need for a More Qualitative Mastication Evaluation

We need to beef up our rationale for changing diets (pun intended!). Indeed, per IDDSI literature reviews: “If the literature on thickened liquids is sparse, this is even more apparent when reviewing the literature regarding texture-modified foods and swallowing (Steele, et al., 2015).  We need more information about what physiological and structural differences, what salivary changes, and what changes in swallowing performance equate to the various diet modifications.

We need more quantitative data collection in our mastication evaluation. Then, we need more research in the future to correlate that data with our instrumental evaluations AND with the levels of standardized diets within the IDDSI Framework. Hint-Hint – this research is not done yet. Unfortunately, I have not yet seen many clinicians broadly using a validated quantitative measure to assess solid bolus intake.

 

That is the purpose of this blog and my creation of this handy pdf form:

Test of Mastication and Swallowing Solids – TOMASS pdf form for the clinic

 

Background on the TOMASS

 

Dr. Huckabee credits her then student, Ruvini Athukorala, with the original concept for the TOMASS, which Athukorala created in 2012-2014 when she was researching skill-based training methods for people with Parkinson’s Disease (per Huckabee, July, 2020). Athukorala needed a test for solids that was similar to the TWST (Timed Water Swallowing Test; Hughes & Wiles, 1996), which asks people to consume 150ml as quickly as is comfortably possible and counts the number of swallows needed to finish.

The TOMASS was created to mirror the TWST, using crackers (aka, biscuits) instead of water (e.g., Saltines, Carr’s Table Water Crackers are readily available in the US and UK, but see the publication for other crackers’ norms).

They had settled on analyzing crackers, as much of the previous mastication research was from dentistry and often used items with too much variability (e.g., ripe vs green bananas, bread) or items that are too dangerous for people with dysphagia (e.g., peanuts). Peanuts have been used in the past research, per Huckabee, as they tend to not mix with secretions. Peanuts were used to measure chewing time and particle size when the bolus was spit out just before the swallow. Huckabee also noted dentistry research using wax tablets of two colors to assess mixing abilities after 5 to 20 masticatory cycles (see Speksnijder, et al., 2009).

In 2018, Huckabee and colleagues published TOMASS’ reliability, validity and normative data across 5 brands of crackers. Huckabee describes the TOMASS as more than just a test for oral dysphagia. She notes that the TOMASS includes chewing and swallowing the cracker, and people are not just chewing the cracker and spitting it out when “swallow ready.” It is a

test of oropharyngeal efficiency for solid bolus ingestion (Huckabee, July, 2020).

 

Per their 2018 research, the following 4 raw data points were the ones that reached statistical significance and showed age and gender differences. Additionally, since there was too much variability on the 2nd trial, they advised to use the raw data from the first trial only.

1. Number of bites per 1 cracker (discrete portions of the cracker taken into the mouth),

2. Number of masticatory cycles (observing jaw movements; see details on the TOMASS pdf form),

3. Number of swallows to finish whole cracker, and

4. Total time from when the cracker passes the bottom lip to when the person is able to say their name out loud. (They found that the task of saying their name out loud encouraged final oral clearance and a clearing swallow).

 

They had other derived measures (e.g., average number of mastication cycles per bite and average number of swallows per bite), but the data from the derived measures “wiped out” the statistical differences.

 

Some of the age and gender differences in this healthy/normal population were quite remarkable and important for SLPs to be aware of.

• It was common for men to take fewer bites, chew less thoroughly, and swallow less often. I wonder how often I may have called that impulsive, when it was actually normal.
• It was also typical for females over 80 to use 4 discrete bites, have around 60 masticatory cycles, and up to 4 swallows, depending on the cracker. How often have I called that “prolonged mastication” or “slow oral preparatory phase / slow oral processing” when it was really just normal?

 

This highlights an important

Take Home Message on Mastication Evaluation

By gathering specific normative data across the age spans, we can stop calling behaviors abnormal when they are really just normal compensatory strategies as we get older (and may not require diet modifications!).

 

TOMASS How To & Tips

 

For more information on HOW to do this test, please see this pdf form of the TOMASS that I created to foster more use in the clinic . This form includes information, directions and normative data (for Saltine & Carr’s, which are available in the US) extracted from their 2018 publication and from Dr. Huckabee’s recommendations during her July 2020 discussion. Here are some tips:

• Use the LAP button on your phone’s clock app to keep track of every masticatory cycle,
• Sit at an angle and view slightly under the chin to track swallows,
• Know that the 2018 research sample included people with dentures, but Dr. Huckabee noted that these were individuals who always wear their dentures for eating. She noted that they accepted participants who were reportedly on a regular diet and eating well, regardless of the status of their dentition.
• You have to count each discrete bite that they take, even if they take tiny bites with no oral processing or swallowing between those bites.
• You can make slash marks on the chart provided to track the total number of bites and number of swallows across the whole cracker.
• Use the additional comments column to address some of the limitations of this test (i.e., saliva status, actual dentition status, and impulsivity. Comment on whether liquid seemed to help. Comment on whether it appeared that the swallows occurred when the bolus was actually swallow-ready? See more on “swallow-ready” below).

 

Cautions for Mastication Evaluation

 

Huckabee noted that this test should be used with caution with people who are critically ill and in acute care. Of course, testing with the TOMASS would likely be at the end of your typical bedside swallowing evaluation (after you already suspect safe intake with purees, minced and soft items). The TOMASS is very useful to challenge the person with a dry solid, similar to how you can challenge people to consecutively sip and swallow 3-ounces of water without stopping. She noted that people with dry mouth may not be able to complete it, and an oral moisturizing agent may be needed. Her publication does indicate that people were offered a glass of water prior to the first cracker, in addition to between cracker trials. Not surprisingly, only 72% of people who had head/neck cancer and radiation could even complete the task, per her recent research collaborations.

Huckabee notes that she uses the TOMASS frequently in the outpatient setting to track progress with her also famous skill-based training research (See BiSSkiT software that will hopefully be available soon via a phone app, per Huckabee, July, 2020). She joked during the July 2020 facebook live that she was only known for crackers, but we know that is not true!

The TOMASS is sensitive to changes in sensation per her research on individuals who received an oral numbing agent. Per her lab’s 2014 skill-based therapy research, Huckabee reported that the TOMASS was not sensitive enough to detect post-therapy improvements in those particular participants with Parkinson’s Disease, as they had more dysphagia to liquids than solids. The participants’ baseline TOMASS measures did not vary significantly from age/sex matched normal controls. However, significant improvements were seen in the TWST with liquids (Athukorala, et al., 2014).

 

Mastication Evaluation for Children

Research has been done to expand normative data to children ages 4 to 18. See the TOMASS-C for pediatric norms by Frank, et al. (2019) in the Journal of Oral Rehab. Huckabee lamented that the confidence intervals for pediatrics were much broader, as many children were getting distracted between bites.

 

 

Limitations & Need for More Research

In addition to the limitations outlined in the publication (e.g., small sample sizes in each age group), Huckabee discussed other limitations during the July 2020 webinar. She noted that the norms may only tell you that your patient is not as fast and efficient as those in the same age group. However, we do NOT yet know what that means. We need further research to compare with instrumental evaluations, and I hear through the dysphagia grapevine, that this research has started in one lab! More info to come…

Huckabee speculated that the TOMASS challenges the bolus preparation, the oral preparatory and oral phase, the pharyngeal pressure generation, and even the upper esophageal sphincter (UES) functioning. A person may be doing many swallows per bite to clear residue through the pharynx and improve clearance through the UES. However, research correlating TOMASS findings to pharyngeal and UES findings on instrumental examinations (i.e., VFSS and FEES) is also needed.

 

During Dr. Catriona Steele’s #DRS2019 Lunch and Learn lecture (2019, March), she pointed out the following limitations in the TOMASS, some of which I addressed above:

• Does not control for variability in dentition or occlusal patterns.
• Does not control for bite size.
• Provides age and sex norms, but it does not account for the size of the person and structural abnormalities. Does the man have a bigger mouth and more powerful jaw muscles, making them faster / more efficient? (See the award winning and epic research by Steele, et al., 2019 and its Appendix for examples of the use of an anatomic scalar to account for differences between people who may have different lengths and sizes of structures like the pharynx at rest. The anatomic scalar uses the “length of the cervical spine between the anterior inferior corners of the C2 and C4 vertebrae,” as originally advised by Molfenter & Steele in 2014).
• Data was not repeatable across trials. In general, for younger participants, the second trials were slower, but for older participants, the second trials were faster.
• Variable fat content of the cracker can affect the performance. (Huckabee’s publication indicated the same issue, suggesting the fat content may have caused the Arnott’s Salada to be overall harder to consume.) However, I did not find significant fat content differences. I double checked the weight and fat content across crackers, and when accounting for the differences in “serving sizes,” the individual crackers are actually very similar. The Salada, Saltines, and Carr’s weighed 3.475, 3.2, and 3.5, respectively. The fat content on the package appears different, especially with vegetable oil being the second ingredient on the Salada box. However, look at the serving sizes and how they are packaged. The Salada comes in a large biscuit of 4 sections, so when Salada says the serving size is 2 biscuits (27.8 grams in weight), that is really 8 individual cracker squares! The serving size weights of the Saltines and Carr’s are only 16 and 14g, respectively.

Therefore, here are the true fat breakdowns:

• • • Saltines have 1.5g of fat for 5 crackers which is 0.3g per cracker.
    • Carr’s Table Water Crackers have 1.0g for 4 crackers, which is 0.25g of fat per cracker.
    • Salada has 2.5g of fat per serving of 8 crackers, which is only 0.31 grams of fat per cracker.

• Saliva quantity and quality (dry mouth, stickier saliva with less mucins. Read more on saliva and the changes in the oral biome that can happen with critical illness.)
• Can we really generalize this information from a cracker to other foods? We need to know this for IDDSI diet modifications!
• During our bedside examinations, we do not see what the person considers to be “swallow-ready.” What does that bolus look like, questioned Steele. What if the person shoves the cracker in with one bite, chews minimally, and swallows the cracker when it is only partially chewed? We would need to comment on these issues, as behaviors such as those will increase choking risks further.

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BONUS SECTION ON SWALLOW-READY

Further exploration of the “swallow-ready” concept is crucial, as it addresses risks of choking. Choking can occur when people don’t orally process their food properly and thoroughly. So, I reviewed my notes and handouts from Dr. Catriona Steele’s and Dr. Koichiro Matsuo’s #DRS2019 Lunch & Learn March, 2019 lectures. (See her shared food oral processing references at end of this blog).

Steele defined Food Oral Processing as the ability to:

• take a piece of (hard) solid food into the mouth,
• fracture it,
• break it down into safe particle sizes,
• mix it with saliva so it is cohesive and “swallow-ready”, and
• then to transport the bolus into the pharynx.

Steele also commented that food oral processing is a “very subjective domain.”

Early research by Hiiemae and Palmer (1999) described the “oropharyngeal aggregation time” as the time during mastication when the food bolus is riding back and forth on the tongue and collecting in the valleculae (space created by the base of the tongue and the epiglottis). Participants oropharyngeal aggregation times varied widely based on the various food textures, but once the food is “swallow-ready,” they noted that the pharyngeal transit times were similar. Steele summarized this as once you are ready to swallow, that swallow-ready bolus should be uniform.

She noted that it was a food oral processing group from France (called INRA) and research by Dr. Laurence Mioche and colleagues who initially put forth that we don’t swallow food until it is “swallow-ready.” Moiche and team’s (2003) research found worrisome trends when they had 25 young adults chew cold beef samples. For both the tough and dry, as well as the tender and juicy textures, females chewed for a shorter time and used less muscle effort/activity than males! Therefore, the females’ concepts of “swallow-ready” boluses were less broken down into small particles, less mixed, and less homogenous or cohesive. The female participants in that study would have swallowed meat that was incompletely processed.

Steele advises clinicians to look at the particle size of a masticated, by having your patients spit out the bolus when they deem it swallow-ready. YES, she thinks we can all get there, if you are feeling a bit squeamish! The average particle size should be roughly 4mm or less, per IDDSI’s Minced & Moist Level 5 (see detailed framework in English again). She mentioned Marie-Angés Peyron’s research (see Steele’s references below) showing that just testing the “number of masticatory cycles” has too much variation among individuals, but the particle size may be a better physical property to assess if the food is “swallowable” or “swallow-ready.” Peyron’s research found that the mean particle size was 1.52mm, but Steele cautioned that this very small particle size may have been due to the specific training in thorough chewing that these young participants received.

The Speksnijder and colleagues’ research (2009) nicely reviewed this concept of comminution tests, which analyzes median natural and artificial food particle sizes that are masticated, expectorated, dried for 24 hours, and then passed through a sieve. (A little beyond our clinical abilities…). They compared comminution tests to the wax tablet mixing test (mentioned above). Healthy participants chewed a silicon artificial test food, and those with natural dentures had a median particle size of 3.3mm. Whereas, people with dentures had 5.0 to 5.3mm particle sizes. I highly recommend reading this article, as it is great to see details of research behind the IDDSI Minced & Moist particle size of 4mm, and it can foster further collaboration with our dentistry colleagues.

Right now, we only have qualitative observation and provide recommendations to individuals with dysphagia, but Steele worries that this may not be best practice. We need validated clinical tests to evaluate people’s “swallow-ready” states across various boluses. Steele and Matsuo shared evidence from coroner’s reports that sticky foods (such as bread) are frequent culprits of choking. They noted that in Japan, death by choking is now more common than car accidents. This may be due to the popularity of foods like Mochi (read more: Patient Safety First blog and konjac jelly cups in Japan), which is very sticky and has been found to be swallowed when it is less orally processed and not swallow-ready. 

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Conclusions on the Need for Mastication Evaluation:

In 2020, Huckabee joked that in her 25+ years of swallowing research, she is best known for her work on “chewing a cracker.” She called that: “a little bit depressing.” However, with the current push for standardization in dysphagia evaluations and standardization of dysphagia diets through the International Dysphagia Diet Standardization Initiative, I think the Huckabee & colleagues contributions have been a huge step. It is time to push for the TOMASS to be used more in the clinic and in research. It is time to explore additional ways to pursue a mastication evaluation and determine if the chewed food (bolus) is at a swallow-ready status.

Of course there is more to consider than just the mastication evaluation. When we as speech-language pathologists recommend diet modifications, we have to realize that we are not just “THE DIET POLICE,” putting people permanently on a modified diet. We are NOT giving out one recommendation into a vacuum, just as we cannot make blanket NPO recommendations. (It is important to stress that SLPs should avoid only providing one NPO recommendation, rather than posing options. One NPO recommendation may corner doctors into only having a feeding tube discussion versus a holistic goals of care discussion with options. We addressed this issue in this SwallowYourPride podcast).

We have to look at the big picture, include many factors, involve the person, caregivers, and medical team. We should provide options with rationale for each option, helping decision-makers see the options as a range of conservative/super cautious to more liberal/accepting of varying levels of risk. Find out where on the continuum the medical team thinks is wise. Ask good questions: how likely is this person to get sick with a pneumonia, have there been exacerbations of respiratory status, have they had a prior choking event? Then, the team needs to find out where the person is along the continuum of accepting risks (i.e., wanting the perceived benefits of staying with a more liberalized oral intake). We should stay involved with this discussion to dispel any myths people have about dysphagia and ensure full understanding of the options and rationales.

Overall, when we are recommending any changes in a person’s diet, we need good qualitative and quantitative data to back that up. Our documentation should have a good summary and rationale to support our recommended options. The person’s nutrition, hydration, health status, safety, and quality of life depend on it.

 

Thank you once again to our dysphagia researchers who are advancing the science of swallowing.

 

Here is that Mastication Evaluation pdf form again:

Test of Mastication and Swallowing Solids – TOMASS pdf form for the clinic

 

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References for Mastication Evaluation

Athukorala RP, Jones RD, Sella O, Huckabee ML. (2014). Skill training for swallowing rehabilitation in patients with Parkinson’s disease. Archives of Physical Medicine and Rehabilitation, 95(7), 1374–1382. https://pubmed.ncbi.nlm.nih.gov/24816250/ https://www.nzbri.org/resources/publications/76/Athukorala_Archives_of_Physical_Medicine_and_Rehabilitation_2014.pdf

Huckabee, M.L., McIntosh, T., Fuller, L., Curry, M., Thomas, P., Walshe, M., McCague, E., Battel, I., Nogueira, D,, Frank, U,, van den Engel-Hoek, L., Sella-Weiss, O. (2018). The Test of Masticating and Swallowing Solids (TOMASS): reliability, validity and international normative data. Int J Lang Commun Disord, 53(1), 144-156. doi: 10.1111/1460-6984.12332. PMID: 28677236.

Hughes, T.A. & Wiles, C.M. (1996). Clinical measurement of swallowing in health and in neurogenic dysphagia. QJM, 89(2), 109-16. doi: 10.1093/qjmed/89.2.109. PMID: 8729551.

Frank, U., van den Engel‐Hoek, L., Nogueira, D., et al. (2019). International standardisation of the test of masticating and swallowing solids in children. J Oral Rehabil, 46, 161– 169. https://doi.org/10.1111/joor.12728

Martin-Harris, B., Brodsky, M.B., Michel, Y., Castell, D.O., Schleicher, M., Sandidge, J., Maxwell, R., Blair, J. (2008). MBS measurement tool for swallow impairment–MBSImp: Establishing a standard. Dysphagia, 23(4), 392-405. doi: 10.1007/s00455-008-9185-9. PMID: 18855050; PMCID: PMC4217120. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4217120/

Molfenter, S. M., & Steele, C. M. (2014). Use of an anatomical scalar to control for sex-based size differences in measures of hyoid excursion during swallowing. Journal of Speech, Language, and Hearing Research, 57(3), 768–778. doi.org/ 10.1044/2014_JSLHR-S-13-0152

Steele, C.M., Alsanei, W.A., Ayanikalath, S., Barbon, C.E., Chen, J., Cichero, J.A., Coutts, K., Dantas, R.O., Duivestein, J., Giosa, L., Hanson, B., Lam, P., Lecko, C., Leigh, C., Nagy, A., Namasivayam, A.M., Nascimento, W.V., Odendaal, I., Smith, C.H. & Wang, H. (2015). The influence of food texture and liquid consistency modification on swallowing physiology and function: A systematic review. Dysphagia, 30(1), 2-26. doi: 10.1007/s00455-014-9578-x. Erratum in: Dysphagia. 2015 Apr;30(2):272-3. PMID: 25343878; PMCID: PMC4342510.

Steele, C.M., Peladeau-Pigeon, M., Barbon, C.A.E., Guida, B.T, Namasivayam-MacDonald, A.M., Nascimento, W.V., et al. (2019). Reference Values for Healthy Swallowing Across the Range From Thin to Extremely Thick Liquids. JSLHR, 62(5), 1338-1363. https://doi.org/10.1044/2019_JSLHR-S-18-0448

Steele, C.M. & Matsuo, K. (2019, March). Something to chew on: Mastication and food development for people with dysphagia. Lunch and Learn Session presented at the Dysphagia Research Society Annual Meeting, San Diego, CA.

Speksnijder, C.M., Abbink, J.H., van der Glas, H.W., Janssen, N.G., van der Bilt, A. (2009). Mixing ability test compared with a comminution test in persons with normal and compromised masticatory performance. Eur J Oral Sci, 117(5), 580-6. doi: 10.1111/j.1600-0722.2009.00675.x. PMID: 19758256.

 

Additional References on Mastication Evaluation and Oral Processing from Steele, 2019, March:

Engelen, L., Fontijn-Tekamp, A., & van der Bilt, A. (2005). The influence of product and oral characteristics on swallowing. Arch Oral Biol, 50(8), 739-746.

Fontijn-Tekamp, F. A., van der Bilt, A., Abbink, J. H., & Bosman, F. (2004). Swallowing threshold and masticatory performance in dentate adults. Physiol Behav, 83(3), 431-436.

Frank, U., van den Engel-Hoek, L., Nogueira, D., Schindler, A., Adams, S., Curry, M., & Huckabee, M. L. (2019). International standardisation of the test of masticating and swallowing solids in children. J Oral Rehabil, 46(2), 161-169.

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