Dysphagia Research

March Research Tuesday

ResearchTuesdayBooksSA Swallowing Services is joining Gray Matter Therapy again for this month’s Research Tuesday!  Research Tuesday was created to “increase accountability for reading research, advocate for reading research, and improving exposure to research.” Every second Tuesday of each month, speech-language pathologists from all settings across the world join together at Gray Matter Therapy to share current literature reviews so that we may all benefit from the most up-to-date research.
This month, Kelley Babcock, MS, CCC-SLP, BCS-S, shares a few of her favorite research studies presented at the 2014 Dysphagia Research Society in Nashville, TN.


Barium on Sushi & MBSS on Dogs: A Roundup of Studies from the 22nd Annual Meeting of the Dysphagia Research Society.  
This past week I attended my first Dysphagia Research Society Annual Meeting, and I am still exhausted.   Each day was packed with back-to-back 15 minute oral presentations and poster sessions of the most current dysphagia research from scholars in a variety of disciplines from across the world.  It was thrilling to hear from some of the greatest researchers in the field of speech-language pathology and enlightening to learn from radiologists, otolaryngologists, gastroenterologists, pediatricians, dentists and even engineers!  I highly encourage you to attend if you ever have the opportunity – I learned a lot, gained some perspective, and met a lot of talented clinicians and researchers.  Pictures weren’t allowed during the presentations, so here is a great shot of my name tag : ).
I could not pick just one study to discuss for Research Tuesday as there were so many that absolutely knocked me off my feet, so below are quick reviews of a few of my favorites.  As an aside, much of this is unpublished and therefore not vetted entirely through the peer-review process.  It is false to assume that because one research study showed a result that this should become standard of care or brought into your practice.
My main takeaway from the whole week was that there is so much more to consider when determining patient swallowing safety, pneumonia risk, and patient outcome than just the presence or absence of aspiration on an instrumental evaluation.  The following studies exemplify this.
Domer, A., Adams, B., Traslavina, R., Plowman, E.K., Kuhn, M., Belafsky, P. (2014, March). Effects of Aspirated Thickened Water on Pulmonary Health and Survival in a Lagomorph Model.  Oral presentation at the 22nd Annual Meeting of the Dysphagia Research Society, Nashville, TN.
This study from the University of South Florida and UC Davis addressed the impact of aspirated thickened water on lung tissue.  The researches compared survival of rabbits after “aspiration” of water thickened with xanthan-gum and water thickened with cornstarch.  (I put aspiration in quotes there because the thickened water was actually inserted into the trachea rather than an aspiration event occurring).
They found that survival rate for the rabbits who received xanthan-gum was 100% whereas survival rate of the rabbits who received cornstarch was only 12.5%.
Takeaway: This study caused quite a stir and also motivated my favorite quote from the week.  During the question and answer portion, a very famous SLP researcher got up to the microphone to make the comment that “now we know that xanthan-gum won’t thicken the liquids as much as starch-based thickener and also won’t kill you as much either.”  Now remember, this is bench science with large quantities of thickened water inserted directly in the trachea of rabbits.  We CANNOT translate this to humans.  This study does not mean that we should never ever ever use starch-based thickeners ever again or that you contributed to the death of a patient by giving him starch-based thickeners, but it does give us some good information to consider.  I personally hate starch-based thickeners and do not use them due to how they change consistencies over time, but if you don’t know much about your thickeners, I hope this study will encourage you to investigate them further – see Dr. Russell Mills research on the topic.  I look forward to the publication of this study and further investigations from these labs.
Troche, M.S., Brandimore, A.E., Okun, M.S, Davenport, P.W., & Hegland, K.  (2014, March).  Reflex Cough Sensitivity in Parkinson’s Disease and Dysphagia.  Oral presentation at the 22nd Annual Meeting of the Dysphagia Research Society, Nashville, TN.
Troche and colleagues from the University of Florida looked at reflex cough thresholds and urge to cough in patients with Parkinson’s Disease (with and without dysphagia) and healthy adults.  Participants in the study were stimulated with capsaicin – the chemical that gives hot peppers their heat – in increasing concentrations to determine the participant’s cough sensitivity and to see which concentration would stimulate a two cough response.
They found that most of their PD participants (with and without dysphagia) did not have a reliable cough at the highest concentration tested.  They also found that in those patients with PD who did have dysphagia, cough reflex thresholds were higher and cough sensitivity was lower.
Takeaway: We frequently see silent aspiration in the PD population, but this term “dystussia,” or impaired cough, was new to me. It was interesting that the PD patients both with and without dysphagia showed decreased sensitivity. It makes perfect sense given the reduced laryngeal function that occurs in PD, but I wonder if cough is something that we could be training/helping to maintain very early in the disease process.  The researchers noted that aspiration pneumonia is the leading cause of death in PD, so I believe these findings are of huge clinical significance.
Ishman, S.L., Sidell, D., Westhoff, T.M., Benke, J.R., Vigilar, M.V., Anderson, R.M., Lefton-Greinf, M.A. (2014, March). Impact of FEES on Feeding Status in Children with and without Neurologic Impairment.  Oral presentation at the 22nd Annual Meeting of the Dysphagia Research Society, Nashville, TN.
Cincinnati Children’s Hospital worked with Johns Hopkins School of Medicine for this retrospective analysis of feeding outcomes after FEES evaluation in children.  The purpose of the study was to determine whether a FEES exam more often resulted in upgrading or downgrading a patient’s diet and whether neurologic or other patient variables would impact feeding status.
The researchers found NPO status changed from 43% prior to evaluation to 21% after evaluation and thus that FEES “liberalized oral feeding status in 52% of children who were NPO.”  Neurologic status and other patient variables did not significantly contribute to feeding status, though the speaker noted that there were more incidences of abnormalities (penetration/aspiration/residue) in patients with neurologic status.
Takeaway: Often patients and families assume that instrumental evaluation will result in a more restrictive diet, but this study found the opposite.  I find the instrumental evaluation to be liberating in that it allows us to truly know what is occurring rather than making guesses or assumptions.  Sometimes the instrumental exam results in a more restrictive diet, sometimes in compensatory strategies, and sometimes in a less restrictive diet, but we won’t know if we don’t look.
I hope you enjoyed this tiny taste of the studies presented at this year’s DRS Meeting.  I plan to follow a few of the other studies, and hopefully when they get published I can do a Research Tuesday write up on them!  Thanks for stopping by SA Swallowing Services webpage for this month’s installment of Research Tuesday – see you next month!

Kelley Babcock, MS, CCC-SLP, BCS-S, is a voice and swallowing therapist from Nashville, Tennessee.  She works as a clinician and educator for SA Swallowing Services which provides basic, advanced and custom FEES courses for SLPs across the country.  For more information on FEES and dysphagia, check out or follow Kelley on twitter @kelleybabcock.

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