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.
- INCLUSION CRITERIA: Included subjects will be healthy adults age 18-65 years with normal swallowing function, as determined with a medical history and physical examination by an otolaryngologist. EXCLUSION CRITERIA: Exclusion criteria include the following circumstances: - Subjects must not have a history of chronic swallowing difficulty or dysfunction. - Pregnant volunteers will be excluded due to risks associated with radiation exposure. - Women who are nursing will be excluded. - Subjects must not currently be suffering from a psychiatric disorder other than depression, as evidenced by being under the care of a psychiatrist, or on medications for treatment of a psychiatric disorder. - History of brain injury or neurological disease. - History of epileptic seizure. - History of Rheumatic fever, mitral valve prolapse, heart murmurs, or cardiac arrhythmias as determined by medical history, physical and EKG will disqualify a subject. - Subjects must not be taking any medications, including herbal types that can affect coagulation. - Subjects will be excluded if they have a history of allergies to lidocaine or any other anesthetic medication.