title: Stage I intraoral food transport: effects of food consistency and initial bolus size.
abstract: OBJECTIVE
  We examined the temporospatial characteristics of stage I oral food transport, in which a piece of solid food is moved from the anterior oral cavity to the postcanine region for chewing. Anteroposterior transport is accomplished by carrying food posteriorly on the surface of the tongue, in contrast to the squeeze-back mechanism of stage II transport from the oral cavity to the pharynx.
  
  
  METHODS
  There were two experiments (Exp1 and Exp2): In Exp1, Twelve healthy young adults ate 2g, 4g, 6g, 8g 12g initial bolus sizes of banana and cookie; in Exp2, fourteen similar subjects ate 6g of banana and cookie with and without radiopaque tongue surface makers. Motions were recorded with videofluorography in lateral projection.
  
  
  RESULTS
  Stage I transport duration was longer for cookie than banana (P≤.025), but there were no significant durational differences among initial bolus sizes. With cookie, tongue pullback was more frequent for small (2g and 4g) than large (12g) bolus sizes (P≤.048). With banana, however, the frequency of pullback was independent of initial bolus size. Kinematic analysis of tongue pullback revealed that the lower jaw opened as the tongue and hyoid bone moved both posteriorly and inferiorly; the magnitude of these displacements did not vary significantly between banana and cookie.
  
  
  CONCLUSIONS
  We conclude that stage I transport is a complex behaviour involving posterior and inferior displacement of the tongue, jaw and hyoid bone. Its frequency of occurrence is related to initial bolus size and consistency, but the magnitude of displacement is relatively constant.
authors.affiliation: Department of Physical Medicine and Rehabilitation Medicine, Johns Hopkins University, 600 North Wolfe Street, Phipps 160, Baltimore, MD 21287, USA; Department of Gerodontology Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo, Tokyo 113-8549, Japan. Electronic address: sirokori5@yahoo.co.jp.
authors.forename: Shinya
authors.initials: S
authors.lastname: Mikushi
authors.affiliation: Department of Physical Medicine and Rehabilitation Medicine, Johns Hopkins University, 600 North Wolfe Street, Phipps 160, Baltimore, MD 21287, USA; Department of Rehabilitation Medicine Kawasaki Medical School, 97 Matsushima, Kurashiki, Okayama 701-0192, Japan.
authors.forename: Sosuke
authors.initials: S
authors.lastname: Seki
authors.affiliation: Department of Physical Medicine and Rehabilitation Medicine, Johns Hopkins University, 600 North Wolfe Street, Phipps 160, Baltimore, MD 21287, USA.
authors.forename: Martin B
authors.initials: MB
authors.lastname: Brodsky
authors.affiliation: Department of Dentistry, Fujita Health University, 1-98 Dengakugakubo, Kutsukake, Toyoake, Aich 470-1192, Japan.
authors.forename: Koichiro
authors.initials: K
authors.lastname: Matsuo
authors.affiliation: Department of Physical Medicine and Rehabilitation Medicine, Johns Hopkins University, 600 North Wolfe Street, Phipps 160, Baltimore, MD 21287, USA; Department of Otolaryngology-Head and Neck Surgery and Center for Functional Anatomy and Evolution, Johns Hopkins University, 600 N. Wolfe St., Phipps 160, Baltimore, MD 21287 USA.
authors.forename: Jeffrey B
authors.initials: JB
authors.lastname: Palmer
mesh_terms: D000293:Adolescent; D000328:Adult; D003679:Deglutition / Q000502:physiology*; D005260:Female; D005471:Fluoroscopy; D005502:Food; D006801:Humans; D007568:Jaw / Q000502:physiology; D008297:Male; D008409:Mastication / Q000502:physiology*; D014059:Tongue / Q000502:physiology; D014741:Video Recording
keywords: Deglutition; Fluoroscopy; Mastication; Oral cavity; Tongue