Posted by Title: Electrical Activity from the Superior Pharyngeal Constrictor during Reflexive and Nonreflexive Tasks
Authors: Perlman, Luschei, & Du Mond
Journal: Journal of Speech & Hearing Research
Year of Publication: 1989
Design Type: Experimental
Purpose: “The purpose of this investigation was to determine, in a quantitative manner, which, if any, nonswallowing tasks produce significant levels of activation in the superior pharyngeal constrictor muscle of normal human subjects”
Population: Normal adult subjects
- Only got a sec?
- If you want to improve swallowing…work on SWALLOWING to make the most impact
- Only got a minute?
- “The superior pharyngeal constrictor muscle had its highest level of activation in reflexive activity, with swallowing producing the greatest amount of activity [100%] and a gag producing about 60% of the activity produced by the swallow“
- “Our results clearly indicate that the reflexive tasks of swallowing and gagging result in the most EMG activity in normal subjects“
- “The two tasks, production of/hok/in which the phoneme /k/ was stressed, and a “modified Valsalva,” which was actually a hard/k/ held for several seconds, produced the next greatest level of EMG“
- “Other tasks, specifically, sucking hard through a tube, production of /a/at the subject’s habitual pitch and intensity, and fry production of~a~, showed levels of activity no greater than that produced at rest“
- Got more time? Keep reading!!
I have done it before. Yes, I’m guilty. My name is Kim, and I was once a /k/ sound abuser user for swallowing.
That was so hard to admit, but they say the first step is acceptance.. Luckily, I have since moved waaaayyy beyond this krazy fad. As one person, I’ve learned so much, but what’s even worse…I still see this going on, in the 21st century nonetheless!!!!
“If you want to work on swallowing, target swallowing.”
I’ve heard this so many times now I kan’t even remember who the original sayer was, but it’s officially cemented inside my skull. It makes sense, no? I mean, if I wanted to learn how to play the guitar, I wouldn’t practice the drums daily🤨.
I’ve been on the search for why this was ever taught to me as a grad student in the first place (mostly to know who to komplain to😂), and I had finally found a source from a reputable SLP idol (hint: name rhymes with koil😉😂). Aside from the fact that the article is half of my birthdate, and my name happens to starts with K (😯😮😲🤯), this was the origin story I’ve been eagerly waiting for.
K so, where to begin…
Even back then, authors still set the scene🎬:
Enter: “past electromyographic (EMG) studies, all showing “greatest amount of EMG activity occurred during swallowing.”
Internal dialogue about kranial nerves: “[The kranial nerves that carry the sensory inputs to the reflex include branches of the trigeminal (V), glossopharyngeal (IX), and vagus (X).]“
Narrator: Damage to the motor and/or sensory system kan leave a person with dysphagia, leading to disuse atrophy “usual sensory stimuli are ineffective in producing activation of the muscles.“
Author #1💁: “What about patient-initiated exercise programs to target these muscles?!“
Author #2🙆: ‘Aha!’
Author #3🙋: ‘We shall measure and kompare the electrical musculature activity of the superior pharyngeal konstrictor muscles for speech and reflexive and non-reflexive speech tasks in normal subjects!’
👏END SCENE. 👏
Sure, not exactly how it went down, but ya get the gist😉.
So the gang got a group together of 15 people (mix men/female, ages ranging from 23-47…which, being in that median area seems like a wide spread!) who apparently konfirmed they were “normal” without any swallowing issues whatsoever. Now, here in the 2000s, I feel like it’s fair game to judge all that we NOW know about all the variability with patient perceptions and subtle swallowing differences/disorders particularly when it komes to things like COPD, Parkinson’s, GERD, HNC, etc. So, imma have to give an eyebrow raise because there’s no way I, as a klinician/reader, can know how these participants were assured to be “normal” since there’s no clarification of this.🤨
So then they decided hey, let’s stick wires all up in their throats and see what happens!😅
Yes, there was much more to that as well, but outside of imagining how they kut the wire, meshed it all together in insulation, measured and placed the wire, it’s just easier for my imagination to go this route. They did apparently do some measurements to know how far was too far in (ouch!), how to navigate around the
internal superior contrictor muscle groups, and just how easy it was to get a gag kausing 20% benzocaine topical anesthetic solution to be used in some participants😬 (at least they waited until 15 minutes after application to kontinue with the task protocol).
They also somehow quantitatively measured (in millimeters) the 8 different parts of the oropharynx for electrode placement as follows:
Their batting average was a total of 672 observations for the analysis, out of a possible 858 if each one of the 13 tasks was kompleted 3 times each out of the 22 sets of EMG data (some participants apparently had 2 electrode pairs?🤔🤔). They explained a bit more about preamplifying artifacts systems and digitizing integrations, but unfortunately as someone who hasn’t personally performed anything similar to this modality (i.e. AmpCare) in years, my brain had a hard time processing the Radioshack-like terms while filtering out a combination of Wh-questions+internal explicatives…
Luckily, the list of 13 tasks the participants had to perform was much easier to get (albeit, somewhat SLP-soul krushing..):
- relax until a baseline EMG signal could be determined (✅)
- suck water through a straw and then swallow, (👍)
- suck through a polyethylene tube connected to a pressure transducer* (🤷♀️)
- perform a traditional Valsava manuever (😉)
- perform a “modified Valsava” ** (😕)
- say the word /ki/ (🤨)
- say the word /hawk/ (😳)
- “suckle” on their index finger (🤭)
- produce “ahh” at a comfortable pitch and intensity (😔)
- produce “ahh” using a falsetto voice (😩)
- produce “ahh” using a vocal fry (🤦♀️🤦)
- laugh (🤣)
- gag ***(🥺)
And there you have it folks. The list that we shall never speak of again. All I kan say is I have no idea if these were randomized, only that the gag was purposefully last on the list for all participants because it would sometimes displace the electrodes and ya know, it’s gross and uncomfortable.🙃
FYI—If you’ll forgive my professional self for one short moment to reference the above, and to acknowledge just how no one outside of our field will ever truly understand what we do with phrases like these😅:
- * When instructed to suck through the polyethylene tube, the subject was told, “Do this as hard as you can until I tell you to stop.”
- ** for the “modified Vlasalva,” instructions were to “Make a /k/ sound as hard as you can for as long as you can; don’t let any air escape”
(it is so hard to pass up on a joke for this let alone with The Office😆)
- *** And I won’t even go where they went with the gag reflex, but let’s just say it was quite variable, with some needing more..ahem..assistance….
(I swear our profession knew what we were doing when we first got into this swallowing gig😂)
K…what?
All jokes aside, they did explain a bit more about the magnitude, amplitude, and their attitudes about how to position the electrodes for measured signals, and then analyze this in a relative way. In all honesty, the only thing I came out somewhat taking away from that paragraph was how I can compare it to some of what I know about high-resolution manometry and the need for more bars/measure points to measure different pressures….otherwise I got nothin sorry.
To start with some things they found:
“The largest ln(EMG) values were recorded for the lateral-superior placements, followed by lateral-inferior, medial- inferior and medial-superior.” p.751
And to that I reply, “K.🤨”
But the real questions on mine and everyone else’s mind:
Does saying the /k/ sound make a heck of a difference?!?
So let’s jump in head first🙃. . .
“The two reflexive tasks, swallowing and gagging, produced significantly higher ln(EMG) amplitudes than did any of the voluntary speech or nonspeech tasks.”
BOOM💣. ROASTED🔥…….I mean to say, isn’t that neat?😁
And here’s where just thinking of Goldilocks will help you understand what they found next:
“A second pair of tasks,/hok/and the “modified Valsalva,” produced in (EMG) values that were significantly smaller than swallow and gag, yet significantly larger than most of the other tasks in the study.” p.751
“A third pair of tasks, falsetto and laugh, had..not significantly smaller than the values produced by the/hak/and ‘modified Valsalva’ tasks, and were not significantly larger than the ln(EMG) levels associated with most of the remaining tasks.”
“Valsalva, suckle, and/ki/were significantly smaller than/hak/and the “modified Valsalva” values, yet were still significantly larger than the baseline EMG.”
“vocal fry, sucking through a tube, and producing a prolonged/a/, did not produce ln(EMG) values significantly different from the baseline value.” p.752
In kase you don’t believe me, the proof may not be in pudding for this, but more just the swallow😉:
Again, they mention different equations about positioning, parameters, and even offer a formula that could be used to “allow one to hold constant(fix) the levels of POSITION and SUBJECT, and compare the relative levels of EMG for different tasks.” But #TBH, glancing over this section made me really open my eyes (and mind) to just what this study really tells us. . .
K, but what does that mean???
Basically:
Nonspeech: 0 Swallowing: 1
This, along with the huuuge variability we know in this day and age regarding swallowing, let alone the gag reflex 😉.
“It was clear that there is a general trend in the amplitude of superior constrictor activity in relationship to task.” p.753
To make it any more clear:
“Our results clearly indicate that the reflexive tasks of swallowing and gagging result in the most EMG activity in normal subjects. These findings suggest that swallowing may be a likely exercise for dysphagia due to weak pharyngeal constrictor function.” p.753
But before we move on, I think it’s super important to address a lot more limitations than the original article lets on. First, the authors luckily acknowledge something super important that so many researchers like to continue to stress (If ya don’t believe me just checkout “Interview with a Researcher–Dr. Brittany Krekeler“): THEY ONLY STUDIED NORMAL SUBJECTS. Yes, it’s nice to know this as a starting point, but when do we treat normal people?? (Answer: hopefully never😉). Question: How can we say a treatment works if we never test it on the general population of patients? Answer: We can’t. (I can’t say my new recipe for a homemade zucchini bread is any good if I’ve never tasted it, right??😉)
Second, can we please use some of our ASHA dues to maybe fly planes in the sky to get the message out just how variable even normal swallowing is?!?? (GoFundMe anyone?😅).
Third, while yes, the authors do state that the “second best” option if swallowing or gagging weren’t options for treatment, saying words ending with “k” and/or “modified valsalva” could be ‘promising’ because they evoked a “reasonable” EMG signal…. And this ‘reasonable’ amount turned out to be a measly 20% of the 100% signal evoked from swallowing.
20% !!!
To drive it home:
“When decreased function occurs in limb muscles, a physical therapy protocol is established in which the affected limb is exercised. Similarly, when a patient has orofacial weakness, the speech-language pathologist includes an exercise protocol in the treatment plan; the goals of this protocol include increasing the strength and mobility of the involved musculature. However, the management of dysphagic patients exhibiting the radiologic diagnosis of pharyngeal paralysis or paresis has been limited primarily to positioning and diet.” p.753
Yes, we still are presented with an uphill battle fighting against the ominous and arbitrary use of diet modifications, but I can bet our PT colleagues still would not prescribe a treatment plan that yielded only 20% of results when there were many new ways to get to 100%.
K, we’re done.
I see you. I hear you. While new pretty gadgets and gimmicks come and go, it can still be just as important to know what evidence there used to be and why. Instead of of just following what someone tells you (me included!), is it not equally (arguably moreso) important to understand how these kooky ideas and theories were born in the first place, in order to know why NOT to do them anymore?? If we never look back, we’ll always be missing a piece that will help show us what the future picture of our field will look like.
If I didn’t have the behind-the-scences knowledge behind the k-words and just “did it because others do it,” or even decided not to do it merely because I’ve heard not to from others (ok, it might depend who those ‘others’ are😉), then really, both parties may still be missing the whole point:
We need to be able to devote some time, whether it be 15 minutes or our entire career, to be willing to make knowledge into a verb form (“knowledge-ize???🤔) in order to know how we got here, why we do/don’t do things as we were told before, and why we are doing what it is we’re doing now—in whatever setting and in whatever period of a career. (Ok, I’m back on the ground from that soapbox😊).
Some call it passion, others call it the need for critical thinking. Either way, there is soooo much better, more current research we can use NOW! Why waste time, energy, and money (i.e. less progress) doing something some may have learned 40 years ago?!? I mean, we don’t still churn butter from a barrel, right?
(In case you missed all the incorrect spellings of words that should have started with “c,” or for those who were cringing and going crazy the whole time reading wondering what the heck is going on?! Just imagine how your patients might feel being told to say all these crazy things😉😅)
Article Referenced: [FREE ACCESS]
Perlman, A. L., Luschei, E. S., & Mond, C. E. (1989). Electrical Activity from the Superior Pharyngeal Constrictor During Reflexive and Nonreflexive Tasks. Journal of Speech, Language, and Hearing Research, 32(4), 749-754. doi:10.1044/jshr.3204.749