Movement of Epiglottis During Swallowing
Condition: Deglutition; Dysphagia
MeSH terms: Deglutition Disorders
Study type: Observational

Summary: 
      This study will examine how the airway closes during swallowing to prevent food or liquid
      from entering the voice box or lungs while eating or drinking. It will also test whether
      electrical stimulation of muscles in the neck can close the airway as it would close during
      swallowing. The long-term goal of this research is to determine the feasibility of a new
      approach for helping patients with a severe and life threatening swallowing disorder.

      Healthy normal volunteers between 18 and 65 years of age who can swallow normally may be
      eligible for this study. Candidates are screened with a medical history, physical
      examination, electrocardiogram and nasolaryngoscopy. For the nasolaryngoscopy, the subject's
      voice box and epiglottis (flap of tissue that covers the windpipe during swallowing) are
      examined using a thin flexible tube with a camera attached that is passed through the nose to
      the back of the throat. During the test, speech and other tasks such as singing and whistling
      are observed. The camera records the movement of the vocal cords on videotape. This procedure
      may be repeated another time during the study.

      Participants undergo the following procedures:

        -  Electrical stimulation of muscles in the neck: The muscles in the neck are stimulated
           with brief low-level electrical currents to see if the stimulation can cause the
           epiglottis to fold down over the windpipe. Stimulation may be increased to a level where
           it feels like a small shock The subject is asked to try to do the muscle stimulation
           while swallowing.

        -  Videofluoroscopy (recording swallowing and muscle stimulation during x-ray imaging of
           the head): The head and neck are x-rayed while the subject swallows. After the wires
           have been inserted for EMG (see below), markers are glued to the tongue and a tube is
           inserted through the nose into the esophagus. The movements during swallowing with and
           without muscle stimulation are x-rayed and analyzed later to determine how the
           stimulation affects the movement of the epiglottis.

        -  Electromyography (EMG): Measurement of the electrical activity of muscles in the neck
           using fine wires placed through the skin into muscles in the chin.

        -  Manometry: During the videofluoroscopy, a manometer (tube that measures pressures) is
           placed through the nose and into the back of the throat at the entry point to the
           esophagus. This test shows whether muscle stimulation can fold down the epiglottis.

        -  Surface electromyography (sEMG): The tube used during the videofluoroscopy has small
           rings embedded in it that measure muscle activity on the surface of the inside of the
           throat.
    

Detailed description: 
      OBJECTIVE:

      Our objective is to determine the factors that cause epiglottic inversion during normal
      deglutition and attempt to recreate this movement by means of muscle stimulation.

      STUDY POPULATION:

      We plan to accrue 30 healthy volunteers so that a set of 20 participants will provide
      reliable data for analysis.

      DESIGN:

      As an observational study, anatomical movement will be examined with videofluoroscopy during
      normal swallows and during stimulation of the thyrohyoid, geniohyoid, hyoglossus, and
      styloglossus muscles.

      OUTCOME MEASURES:

      The principal outcome of this study is the distance of epiglottal displacement as measured
      from videofluoroscopic images during normal swallowing and muscle stimulation. Secondary
      measures are assessed as correlates of epiglottal inversion. These data include motion and
      kinematics of other structures, such as the hyo-laryngeal complex and the tongue; tongue base
      retraction pressures in the oral-pharynx, the hypopharynx, and the UES; and muscle activity
      as measured by surface electromyography in these three locations.
    

Time perspective: Prospective
Keywords: Swallowing Disorders; Swallowing; Videofluoroscopy; Dysphagia; Epiglottis; Healthy Volunteer; HV