Physiological Flow of Liquids Used in Dysphagia Management (Previously Tongue-Pressure Timing for Liquid Flow Detection and Control in Swallowing)

Study Purpose:

For individuals with neurodegenerative conditions, such as Amyotrophic Lateral Sclerosis and Parkinson disease, swallowing impairment (i.e., dysphagia) is a common and serious symptom. Dysphagia places the affected individual at risk for secondary health consequences, including malnutrition and aspiration pneumonia, and negatively affects quality of life.

Thickened liquids are commonly recommended for individuals with dysphagia, as they flow more slowly and reduce the risk of entry into the airway. However, there is limited understanding about how changes in liquid thickness modulate swallowing physiology in individuals with neurodegenerative conditions, and previous reports have shown that increased liquid thickness may contribute to the accumulation of residue in the throat.

The purpose of this study is to explore swallowing physiology and function in individuals with neurodegenerative conditions, across five levels of liquid thickness (thin, slightly-thick, mildly-thick, moderately-thick, and extremely-thick), and to identify boundaries of "optimal liquid thickness", which maintain airway safety, without contributing to the accumulation of significant residue. Results from this study will help guide the clinical recommendations for thickened liquids in dysphagia management.


Amyotrophic Lateral Sclerosis (ALS),  Familial ALS,  Sporadic ALS

Study Type:

Observational Study

Study Category:

Diagnostic Test: Videofluoroscopic Swallowing Examination and Tongue Strength Measurement

Study Status:

Not enrolling


Not Applicable

Study Chair(s)/Principal Investigator(s):

Catriona M Steele, PhD, University Health Network - Toronto Rehabilitation Institute
Emily K Plowman, PhD, University of Florida ID (11 digit #):


Neals Affiliated?


Coordinating Center Contact Information

University Health Network - Toronto Rehabilitation Institute
Melanie Peladeau-Pigeon, MSc / .(JavaScript must be enabled to view this email address) / 416-597-3422 ext 7619
Kelby Magennis, MPH / .(JavaScript must be enabled to view this email address) / 352-273-8632
Toronto, Canada

Full Study Summary:

This research study will measure swallowing function in individuals with Amyotrophic Lateral Sclerosis or Parkinson's disease. The aims of this study are to (1) identify parameters of swallowing physiology that are associated with impaired swallowing safety and efficiency, and (2) explore how liquid thickness influences swallowing function.

Participation in this research study involves a single appointment at the University of Florida Swallowing Systems Core laboratory located at Shands Hospital, Gainesville. The appointment will last approximately 1 hour, and will involve tasks to measure tongue-strength, and a dynamic swallowing x-ray (known as videofluoroscopy) to evaluate swallowing function. A selection of demographic information (e.g., age, onset of symptoms) will also be recorded.

To measure tongue strength, participants will be given a disposable air-filled bulb and asked to perform a series of tongue presses, and swallow their saliva. Next, during the videofluoroscopy, participants will take sips of various liquids ranging in thickness from thin (like water), to extremely-thick (similar to the consistency of pudding or yogurt). The liquids will be mixed with a safe substance called barium, to make them visible on x-ray images. After the videofluoroscopy has been completed, each participant will have their tongue strength measured again, which will conclude their participation in the study.

Swallowing physiology will be measured from the videofluoroscopy images, post-hoc, by an experienced team of blinded raters.

Study Sponsor:

University Health Network, Toronto

Participant Duration:

Estimated Enrollment:


Estimated Study Start Date:


Estimated Study Completion Date:


Posting Last Modified Date:


Date Study Added to

  • Eligibility Criteria


    Female, Male

    Minimum Age:


    Maximum Age:


    Time since Symptom Onset:


    Time since Diagnosis:


    Can participants use Riluzole?


    Inclusion Criteria:
    Adults (18+) with a confirmed diagnosis of Amyotrophic Lateral Sclerosis (ALS) or Parkinson's disease (PD)
    Reported speech or swallowing problems

    Exclusion Criteria:
    People with a prior medical history of stroke
    People with a prior medical history of acquired brain injury
    People with a prior medical history of spinal or spinal cord injury
    People with a prior medical history of cancer or surgery in the head and neck region
    People who have had radiation to the head and neck for cancer
    People who have a prior history of swallowing problems (e.g., from childhood, medical complication)
    People with significant breathing difficulties (e.g., rely on mechanical ventilation)
    People who rely solely on tube-feeding for all meals and nutrition
    People who have Type I (insulin-dependent) Diabetes
    Women who are pregnant
    People who have allergies to barium, potato starch, corn starch, xanthan gum, milk products, latex or dental glue

  • Site Contact Information

    University of Florida
    Emily K Plowman, PhD / .(JavaScript must be enabled to view this email address) / 352-273-9215
    Kelby Magennis, MPH / .(JavaScript must be enabled to view this email address) / 352-273-8632
    Gainesville, Florida 32611
    United States