title: Variability in execution of the chin-down maneuver by healthy adults.
abstract: OBJECTIVE
  The chin-down maneuver is commonly used in dysphagia management to facilitate greater airway protection. However, the literature suggests that variation in maneuver execution may threaten the effectiveness of the intervention. Our goal was to study variation in chin-down maneuver execution given a uniform instruction.
  
  
  METHODS
  Sagittal view digital video recordings were acquired from 408 healthy adults who performed sequences of reiterated water swallows in head-neutral and chin-down positions. Head angle measurements were extracted from the recordings, using markers on goggles worn by 176 participants.
  
  
  RESULTS
  We observed considerable variation in head angle in the head-neutral swallowing task, with a trend to greater flexion in participants over the age of 65. Male participants showed greater variation in head angle than females. Head flexion during the chin-down swallowing tasks averaged 19°, in the range reported to yield clinical benefit in radiographic studies.
  
  
  CONCLUSIONS
  We conclude that a clear, uniform instruction is adequate to facilitate execution of the chin-down maneuver to a degree that is likely to be of clinical benefit. The variation in head angle observed in this study warrants further research, particularly regarding the relationship between anatomical cervical spine curvature and head angle influence on swallowing.
authors.affiliation: Toronto Rehabilitation Institute, Hamilton, Ont., Canada. steele.catriona@torontorehab.on.ca
authors.forename: C M
authors.initials: CM
authors.lastname: Steele
authors.forename: D
authors.initials: D
authors.lastname: Hung
authors.forename: E
authors.initials: E
authors.lastname: Sejdić
authors.forename: T
authors.initials: T
authors.lastname: Chau
authors.forename: S
authors.initials: S
authors.lastname: Fraser
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000886:Anthropometry; D002574:Cervical Vertebrae; D002680:Chin; D003679:Deglutition / Q000502:physiology*; D003680:Deglutition Disorders / Q000503:physiopathology / Q000628:therapy; D004825:Epiglottis; D005260:Female; D019416:Head Movements / Q000502:physiology*; D006801:Humans; D007568:Jaw; D008297:Male; D008875:Middle Aged; D011187:Posture; D012016:Reference Values; D055815:Young Adult