The mistaken Masako…fact, fiction, or fantasy?

To follow up after last month’s post A clinician’s review on reviewing the research, we’re now exploring the evidence into the mystery behind the Masako/tongue-hold maneuver👅. Just some of the questions piling up even before going through all those steps in finding all the studies below:

What is it?🤔

Where did it come from?😐

What does it do?🧐

What doesn’t it do?😓

Should we be doing it?🤨

What’s the evidence rationale associated with it?🤓

I remember thinking long ago this exercise would be good for all those back of the tongue issues. Naively, it made sense to an uninformed me ‘If you pull the tongue forward, it’ll make the back of the tongue work harder to move backward like during a swallow.”

To leave off from last time, after using a plethora of Resources to help me discover just what kind of question to ask, what kind of studies to look for, and a way to easily and neatly keep track of all my results, now I was closer to finding out what all the evidence has been saying and why I still had so many questions to try to answer my original question: “Is the Masako/tongue-hold an effective treatment for improving swallow physiology?”

After the process of eliminating irrelevant or unrelated results, I was left with only a handful of studies to dig deeper into as I set out to find any answers I could in order to clear up and clean out anything in my swallow toolbox that may be a facade or unnecessary. . . .

Before diving right in:  Because I personally have never used most of the technical systems, software, equipment, and procedures before, I definitely can’t speak to all the details and specific technical talk that are referenced in most of the studies, so I highly recommend checking out the full articles for further information on this.😉

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First, up:

“In a group of young and elderly healthy research participants, this study investigated age-related differences associated with the tongue-hold swallowing maneuver, a rehabilitative exercise commonly recommended for strengthening of the PPW during swallowing” p.4

The authors wanted to essentially answer the questions:

1. “Does the tongue-hold maneuver significantly affect pressure generation in the pharynx and UES compared with noneffortful saliva swallows in both young and elderly participants?”
2. “Are changes in pressure generation observed in the pharynx and UES during tongue-hold swallows significantly affected by age and sex?”

Basically, they looked at a LOT of different things (Masako, age, gender, different areas of pressure) and wanted to see if any of it had an impact on everything else!🤯

They had their 68 healthy adult subjects (34 young, 34 old) each complete  5 “non-effortful saliva swallows” and 5 “tongue-hold swallows” with “one swallow approximately every 30 seconds.”👅

No, we didn’t know how far out a tongue had to be nor was there any randomization in the swallow tasks (apparently to avoid a carryover effect in case the tongue-hold impacted a normal swallow afterward). But we did know a manometric catheter with “3 unidirectional pressure transducers spaced 3 cm apart” was placed transnasally while the subject sat upright with a 5 minute accommodation period before any swallows.

“The pressure sensors of the catheter were therefore placed in the oropharynx (Sensor 1, most proximal), the hypopharynx (Sensor 2), and the high-pressure zone of the UES (Sensor 3, most distal)” with all sensors facing towards the posterior pharyngeal wall” p.3

And for the resulting big reveal:

“Tongue-hold swallows generated overall lower pressure in the oropharynx and hypopharynx across both age groups.” p.4

“At the level of the UES, the effects of the tongue-hold maneuver differ greatly between age groups, with elderly participants displaying increased relaxation pressures and young participants displaying a trend toward decreased relaxation pressures during tongue-hold swallows.” p.6

Overall, this study turned out to be a pretty interesting look into age and/or gender differences when it came to using this Masako maneuver. And while I’m not as sold on the authors’ conclusion that some differences in the tongue-hold for men would likely be contributed to “overall, larger oropharyngeal anatomy” farther protrusion for a greater effect🤨; they do offer a better brief summary when it comes to the known implications for sarcopenic dysphagia in the elderly, and how these can also likely provide a rationale for reduced UES opening for the tongue-hold maneuver and longer periods of pressure across the board:

“An age-related decrease of tongue and pharyngeal constrictor muscle strength would result in generally reduced contractile power. Therefore, these muscles would take longer to reach peak contraction, which would result in overall longer pressure durations..” p.6

“It may be that tongue protrusion in the elderly participants impaired UES opening due to reduced or less coordinated superior-anterior elevation of the hyolaryngeal complex during tongue-hold swallows.” p.5

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Next:

This study picked up right where the last study left off, new and improved!

The authors were a bit more focused on not just seeing if there was a change, but specifically where and how that change might’ve happened. So the authors wanted to find more answers by examining if specific muscles and associated manometric pressures changed during the Masako maneuver.

Even though there were fewer healthy young subjects (8 total, 20-27 y/o), they used more dynamic and specific measures for pressure and muscle activity across 3 randomized swallow tasks:

1. saliva swallow with tongue tip without tongue-hold maneuver (x5)
2. saliva swallow with tongue tip at the lip (x5)
3. saliva swallow during the tongue-hold maneuver (x5)

But why look at the muscle activity too?

“Given the role of the tongue and posterior pharynx to generate swallow-related pressure, and the potential for the tongue-hold maneuver in swallow rehabilitation, it is of interest to examine how muscle contraction and manometric pressure may change during the tongue-hold maneuver.”

“Although recent evidence suggests reduced pharyngeal swallow pressure during the tongue-hold maneuver, the relative contribution of the superior pharyngeal constrictor and genioglossus to pharyngeal pressure remains unknown.” p.3

The authors hands-down give an amazing review of the anatomy and physiology for which specific muscles and nerves are at play during normal swallowing and likely would contribute to this specific tongue-resistant maneuver. Additionally, they also go further by reminding us of the neural players (✅check off your Cranial Nerve Bingo for #9, #10, #12) while also bringing up the motor equivalenceº theory behind it all:

“It is important to note that sensory feedback from oropharyngeal receptors to the medullary swallow center may be important to regulate intrapharyngeal swallow pressure in response to the altered tongue position…These neuromuscular mechanisms may account for the hypothesized increase in superior pharyngeal constrictor muscle activity in the presence of the tongue-hold maneuver.” p.2

I don’t know about you, but I’m still mind blown away by their super thought-out rationale and am still trying to wrap my head around all of it!🤯🥴

The authors kicked things up a bit by also giving a lot of thought into just how they were going to measure what they wanted.

Some main differences from the prior study:

• instead of a manometric catheter with “3 unidirectional pressure transducers spaced 3 cm apart”, they used one that had high-resolution manometry with 36 circumferential pressure sensors spaced 1 cm apart (so more sensors all the way around+closer together)
• they also used intramuscular electromyographyº – where needle electrodes were inserted into the genioglossus, cricopharyngeus, and superior pharyngeal constrictor muscles (yes- directly into the muscles!)
• as well as bilateral sEMG electrodes at the submental region between the mandible and the hyoid bone

So with much more specific and a bit more robust measures, they ended up finding:

As far as muscle activity goes with tongue-hold:

“For muscle activity, we found that the pre-swallow magnitude of submental, genioglossus, superior pharyngeal constrictor, and cricopharyngeus electromyography signals increased.”

During the swallow, the magnitude and duration of submental, genioglossus, and superior pharyngeal constrictor muscle activity each increased.

However, the magnitude and duration of cricopharyngeus muscle activity were unchanged during the swallow.” p.5

And as far as any pressure-related changes with tongue-hold:

“As hypothesized, the pre-swallow pressures and the swallow pressures and durations remained unchanged. Our results suggest that the tongue-hold maneuver may result in increased tongue and pharyngeal muscle activity, with relatively stable pharyngeal pressures.” p.5

Ever feel like you’re working hard with no big changes? So do all these muscles!

 

Finally, the authors call for future studies to include manometric, electromyographic, and imaging modalities to really capture all the needed information in order to determine any sort of exercise regimen for a clinical benefit for patients with dysphagia.🤷‍♀️

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So this one actually crept up on me a little later (there’s also the possibility I overlooked it🤭). But I’m glad I was able to remember Dr. Pisegna’s thesis article because while not the most overwhelmingly definitive conclusion, it did give me a bit more history and origin story behind this Masako maneuver:

“The impetus for the maneuver named after Dr. Masako Fujiu” from his early work with subjects who had their anterior portion of their tongue removed. Thereby, making way for “the original intent of the tongue-hold maneuver was to target the pharyngeal wall” while observing immediate effects of the tongue-hold maneuver. Eventually, researchers “anticipated that over time, this may result in greater activity of the pharyngeal wall musculature.”

Well, at least we can cross off one basic question!👍

Pisegna’s study sought to look at specifically the effectiveness of the tongue-hold as a strengthening exercise for a weak swallow, and as a Phase 1 Pilot study, also wanted to give some answers to questions like

1. “Is the tongue-hold maneuver beneficial?”
2. “What muscle groups are strengthened by this exercise?”

With 5 dysphagic adult subjectsº plus the actual primary investigator (how’s that for research involvement?!) completing the tongue-hold x3/day, x5/week, across 6 weeks at ‘80% of each subject’s maximum repetitions until fatigue,’ the 4 healthy adult control subjectsº didn’t do anything still having their lingual strength measures taken along with the dysphagia group at baseline and 6 weeks.

What they looked at and what was found:

• Dysphagia Handicap Index (DHI)º

“No overt trends in the subject-reported outcomes on the swallowing scale were
noted: approximately half reported improvement, half reported worsening” p.36

• Iowa Oral Performance Instrument (lOPI)º

“In general, the exercise group showed increases in lingual pressures (albeit non-significant), but not much greater than the expected variability.” p.36

• Boston Residue and Clearance Scale (BRACS)º with FEES protocolº

“Regarding pharyngeal residue, a broad glance at the lack of statistical significance and lack of improvement on total scores does not adequately represent very real changes that may have occurred.” p.38

• Manometry for Pharyngeal Pressuresº

“The pharyngeal pressures suggest that 1 out of 2 measured subjects and the PI
strengthened their oropharyngeal pressures on saliva swallows. Unfortunately, the data are variable and manometry was performed on only 2 of the 5 subjects and the PI due to equipment problems.” p.42

“The present study found an interesting decrease in the UES resting pressure for [subject 5] S5” p.44

What with a couple of subjects dropping out, some difficulty following up for the 3-week and 6-week measures, along with equipment malfunctioning, learning effects, and a super small and wide-range sample size, the study at least gives a thorough rationale and reminder for their exercise-science-based swallowing procedures for contraction type, task specificity, overload, and dose to help their ultimate conclusion:

“This pilot study suggests that clinicians should continue to prescribe the tongue-hold maneuver as an exercise with caution, as some patients may benefit from it while others may not.” p.47

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This one was a lot more simple and short but also left me with even more gaps to fill in.

With a single purpose in mind (to compare improvements in swallow function from the Masako vs NMES in stroke patients with dysphagia), the 47 subjects completed their respective interventions for 20 minutes a day, x5 a week, across 4 weeks. VitalStim certified clinicians placed electrodes on mylohyoid/thyrohyoid muscles and also utilized VFSS with the FDSº (Functional Dysphagia Scale) to measure outcomes.

Because this study was so simplistic in its methods, the results were simple enough too:

“no significant difference between the two groups. However, the mean values of FDS after treatment in both groups decreased.” p.2

Nor were there any differences in gender, time since dysphagia, or average FDS. If you have a lot more questions after this basic info, then you’re not alone! I had so many question marks popping up with this article (like, how was stroke confirmed? Why 20 minutes? How did they confirm Masako was actually executed accurately? And maany more…). While an incredibly short and simple read which at least looked at the disordered population, unfortunately, it wasn’t really on the same level as the others because there were just so many holes throughout.😕

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Last up and the most recent:

Here, similar swallow maneuvers were employed again: normal saliva swallow, weak tongue-hold, and strong tongue-hold for 22 healthy adult subjectsº. This time, the authors used ‘high-resolution manometry with a novel, objective pressure-flow analysis’ as the main way to measure pressure changes in the pharyngoesophageal swallow.

Obviously, I was scratching my head too after trying to figure out what all that actually was🤔, but luckily the authors were nice enough to share some basic understanding:

“the contractile integral, which defines pressure over space and time, has gained popularity as a measure of the ‘vigor’ of the pharyngeal swallowing response. Altered pharyngeal contractile integrals associated with aging, different volumes, or swallowing maneuvers have been reported.”

“In this study, we quantified the effects of THS on pharyngoesophageal function using HRM and a novel, objective pressure-flow analysis. We hypothesized that the pharyngeal contractile integral measured by the pressure-flow analysis is enhanced with THS (tongue-hold swallow).” p.2

Their transnasally inserted manometric catheter with 1 cm spaced 36 unidirectional pressure sensors was placed through the upper esophagus and into the proximal esophagus’ of each subject. A clear ruler measured out the length of each protruding tongue (1 cm “weak” tongue-hold vs 2 cm “strong” tongue-hold) as the subjects completed each swallow task twice randomly 60 seconds apart after some pre-practice accommodation periods.

There are lots more high-resolution manometry details packed in there, but it was interesting how the authors made a point to include some higher-quality measures and ensure the researchers analyzing the actual numbered data were blinded to the swallow type (normal, weak, strong THS):

“Velopharyngeal, mesopharyngeal, hypopharyngeal, and whole pharyngeal contractile integrals and the UES integrated relaxation pressure were analyzed using a semi-automated analysis portal (Swallow Gateway™)…This portal has excellent inter and intra-rater reliability.” p.4

Drumroll please🥁🥁🥁🥁🥁………

“First, THS enhanced the velopharyngeal contractile vigor, which was in accordance with our hypothesis.

Second, THS prolonged the mesopharyngeal contraction duration. 

Third, weak and strong THS contributed equally to the biomechanical changes in velopharyngeal contractile vigor and mesopharyngeal contraction duration” p.4-5

I felt the same way. Ultimately, there were differences in contraction (at least in the oropharyngeal areas). Although they try to make some claims that ‘a larger protrusion of the tongue during THS will render the initiation of swallowing more difficult,’🤨 their results did not suggest this for the pharyngeal or UES pressures (instead they suggest a ceiling effect as a possible reason). Their overall conclusion leads us a little further, but with no real meaningful gains for what to do😩:

“Thus, in the presence of a restricted tongue retrusive movement while the tongue is held anteriorly, THS may require stronger and longer pharyngeal swallowing without a pressure increment at the mesopharynx using the middle pharyngeal constrictor. Thus, THS is likely to serve as a resistance exercise for the muscles that are involved in bolus propulsion.” p.5

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Okay, I tried my very darn best to summarize all the above and I don’t know about you, but I could definitely use some kind of comforting food to digest while I try to process all this info.🥴

My first thoughts after reading and trying to process (let alone comprehend) all the above studies:

 

How I honestly felt after all reading these recent studies for more answers or know what was ‘best practice’:

 

And my overall reaction to all the unanswered questions, unfilled gaps, and unknowns across the lack of actual evidence for this:

Needless to say, it’s been a surprisingly frustrating journey🙄. After searching for, locating, reading, interpreting, processing, and trying to understand these studies after all this work, as a clinician I’m not gonna lie, I still feel helpless, a little hopeless, and guide-less.

On the one hand, it does seem as the saying goes, “there’s something there🧐.” With some studies able to share some insights into thoughtful rationales and theoretical groundwork to lay the foundation for what we can still only assume would hold true for the Masako, the evidence we actually need in order to go further and factually support all this underlying knowledge appears to be as scarce as many items during a supply chain crisis😓.

While most of these studies really do show us something and give us some results, because they all appear to be more of a mix-and-match bag, not only do we end up with something not 100% definitive for clinicians, but we can’t really even compare them all to each other in the same way. Put another way, while we know all these studies are a type of fruit, because they all look at different things, in different ways, with different measures and different methods, it feels a lot more like comparing an apple🍎 to a watermelon🍉 to a banana🍌 to a grape🍇!!

As fast-walking-fast-talking clinicians, we’re not gonna just wait around twiddling our thumbs right?

So, what do we do?!??!

Apparently the researchers nor ASHA apparently have a definitive answer to that.🤷‍♀️ But let’s imagine a world of grey where:

For clinicians: Just like with soo many things in our still-somewhat-new professional field, we need to still use what we do know about our patients, what we think might be best, and use critical thinking to form rationale hypotheses for this. Personally, I usually tend to stray from blanketed or hyperbolic “always/never” statements or ways of thinking. And for this topic especially, it seems there could likely be valid arguments made for both sides!

For researchers: Luckily, there does seem to be a growing trend at least in the studies, with future studies absolutely needing to include ways to measure not only pressure-related changes in the entire oropharynx/pharyngoesophageal segments (hopefully with the most advanced equipment😉), but also include ways to measure changes in tongue strength, muscle activity, patient subjective reporting (with data for adherence!😉), instrumental swallow study quantitative/objective measures, and overall functional measures like changes on texture restrictions or progress in swallow safety/efficiency. Phew!😱 All that for the actual disordered populations we are going to treat with a clinically relevant exercise-based regimen! No sweat right?!😅

Since no one is perfect, please shoot me a message if I missed any critical studies (this was a bit of a big undertaking for me so there’s always a chance😉). Hopefully, in the near future, there will be more to review and think critically about.

For now, hopefully we’ll all keep our questioning-clinician caps on *whenever/if ever* we’re in this puzzling position, and at least think twice before automatically assigning everyone from the Queen of England to the band KISS to stick those tongues out without at least having some thought behind it.🤪🤔

 

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Articles Referenced:

 

1. Doeltgen, S., Macrae, P., & Huckabee, M. (2011). Pharyngeal Pressure Generation During Tongue-Hold Swallows Across Age Groups. American Journal Of Speech-Language Pathology, 20(2), 124-130. doi: 10.1044/1058-0360(2011/10-0067)

2. Hammer, M., Jones, C., Mielens, J., Kim, C., & McCulloch, T. (2014). Evaluating the Tongue-Hold Maneuver Using High-Resolution Manometry and Electromyography. Dysphagia, 29(5), 564-570. doi: 10.1007/s00455-014-9545-6

3. Pisegna, 2021. The efficacy of the Masako (tongue-hold) maneuver. [online] Boston University Libraries. Available at: <https://open.bu.edu/handle/2144/12190> [Accessed 24 October 2021]
4. Byeon, H. (2016). Effect of the Masako maneuver and neuromuscular electrical stimulation on the improvement of swallowing function in patients with dysphagia caused by stroke. Journal Of Physical Therapy Science, 28(7), 2069-2071. doi: 10.1589/jpts.28.2069
5. Aoyagi, Y., Ohashi, M., Ando, S., Inamoto, Y., Aihara, K., & Matsuura, Y. et al. (2021). Effect of Tongue-Hold Swallow on Pharyngeal Contractile Properties in Healthy Individuals. Dysphagia, 36(5), 936-943. doi: 10.1007/s00455-020-10217-9

Developing the Tongue Holding Maneuver. (2018). Retrieved 24 October 2021, from https://pubs.asha.org/doi/pdf/10.1044/sasd11.1.9

Snippet from ASHA: