title: Changes of timing variables in swallowing of boluses with different viscosities in patients with dysphagia.
abstract: OBJECTIVE
  To evaluate the timing of the swallowing process and the effect of bolus viscosity on swallowing.
  
  
  METHODS
  Prospective observational study.
  
  
  METHODS
  General teaching hospital, rehabilitation unit.
  
  
  METHODS
  We enrolled patients with dysphagia (n=82) in a videofluoroscopic swallowing study (VFSS) from January 13, 2009, to October 22, 2009. Based on VFSS results, we classified patients as "thin-fluid aspirators" (n=40) or as "nonaspirators" (n=42).
  
  
  METHODS
  Swallowing of a 5-mL thick bolus and a 5-mL thin bolus in all patients.
  
  
  METHODS
  Kinematic analysis of various variables during the swallowing process (pharyngeal phase), including epiglottis contact with the bolus, laryngeal elevation, pharyngeal constriction, and upper esophageal sphincter opening.
  
  
  RESULTS
  In both groups, the thin bolus arrived at the vallecular pouch earlier than the thick bolus. During swallowing of the thick bolus, the thin-fluid aspirators had a delayed latency of upper esophageal sphincter opening, delayed laryngeal elevation to peak level, and significantly longer rise time of laryngeal elevation.
  
  
  CONCLUSIONS
  Our results indicate clear differences in the degree of adaptation to bolus viscosity between patients classified as thin-fluid aspirators and as nonaspirators. These differences were mainly in activities of laryngeal elevators rather than pharyngeal constrictors.
authors.affiliation: Department of Rehabilitation Medicine, University of Ulsan College of Medicine, Seoul, Korea.
authors.forename: Sang Il
authors.initials: SI
authors.lastname: Lee
authors.forename: Jong Yoon
authors.initials: JY
authors.lastname: Yoo
authors.forename: Minyoung
authors.initials: M
authors.lastname: Kim
authors.forename: Ju Seok
authors.initials: JS
authors.lastname: Ryu
mesh_terms: D000368:Aged; D003680:Deglutition Disorders / Q000145:classification / Q000000981:diagnostic imaging / Q000503:physiopathology*; D005260:Female; D005471:Fluoroscopy; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D013997:Time Factors; D014741:Video Recording; D014783:Viscosity