title: The relationship between hyoid and laryngeal displacement and swallowing impairment.
abstract: OBJECTIVE
  Reduced range of hyoid and laryngeal movement is thought to contribute to aspiration risk and pharyngeal residues in dysphagia. Our aim was to determine the extent to which movements of the hyoid and larynx are correlated in the superior and anterior directions in swallowing, and whether movement range is predictive of penetration-aspiration or pharyngeal residue.
  
  
  METHODS
  Prospective, single-blind study of penetration-aspiration and pharyngeal residue with objective frame-by-frame measures of hyoid and laryngeal excursion from videofluoroscopy.
  
  
  METHODS
  Tertiary hospital and rehabilitation teaching hospital.
  
  
  METHODS
  Twenty-eight participants referred for videofluoroscopy: 13 women, aged 57-77; 15 men, aged 54-70. Individuals with known neurodegenerative diseases or prior surgery to the neck were excluded. Each swallowed three boluses of 40% w/v thin liquid barium suspension.
  
  
  RESULTS
  Two speech-language pathologists independently rated penetration-aspiration, vallecular and pyriform sinus residue. Cervical spine length, hyoid and laryngeal displacement were traced frame-by-frame. Predictive power was calculated.
  
  
  RESULTS
  Cervical spine length was significantly greater in men. Hyoid displacement ranged from 34-63% of the C2-4 distance. Arytenoid displacement ranged from 18-66%, with significantly smaller anterior displacement in men. Positive hyoid-laryngeal movement correlations in both axes were the most common pattern observed. Participants with reduced displacement ranges (≤ first quartile) and with abnormal correlation patterns were more likely to display penetration-aspiration. Those with reduced anterior hyoid displacement and abnormal correlation patterns had a greater risk of post-swallow pharyngeal residues.
  
  
  CONCLUSIONS
  It is difficult for clinicians to make on-line appraisals of the extent to which hyoid and laryngeal movement may be contributing to functional swallowing consequences during videofluoroscopy. This study suggests that it is most important for clinicians to discern whether reduced anterior displacement of these structures is contributing to a patient's swallowing impairment. Measures of structural displacement in thin liquid swallowing should be corrected for variations in participant height. Reductions in anterior hyoid and laryngeal movement below the first-quartile boundaries are statistically associated with increased risk for penetration-aspiration and post-swallow residues.
authors.affiliation: Toronto Rehabilitation Institute, University of Toronto, Toronto, ON, Canada. steele.catriona@torontorehab.on.ca
authors.forename: C M
authors.initials: CM
authors.lastname: Steele
authors.forename: G L
authors.initials: GL
authors.lastname: Bailey
authors.forename: T
authors.initials: T
authors.lastname: Chau
authors.forename: S M
authors.initials: SM
authors.lastname: Molfenter
authors.forename: M
authors.initials: M
authors.lastname: Oshalla
authors.forename: A A
authors.initials: AA
authors.lastname: Waito
authors.forename: D C B H
authors.initials: DC
authors.lastname: Zoratto
mesh_terms: D000368:Aged; D003679:Deglutition / Q000502:physiology*; D003680:Deglutition Disorders / Q000000981:diagnostic imaging / Q000209:etiology* / Q000503:physiopathology; D005260:Female; D005471:Fluoroscopy; D005500:Follow-Up Studies; D006801:Humans; D006928:Hyoid Bone / Q000000981:diagnostic imaging / Q000503:physiopathology*; D007830:Larynx / Q000000981:diagnostic imaging / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D016037:Single-Blind Method; D014743:Videotape Recording