title: Bolus location at the initiation of the pharyngeal stage of swallowing in healthy older adults.
abstract: This study characterized the vertical position of the bolus head at the onset of the pharyngeal swallow in healthy older adults. Lateral-view videofluoroscopic (VF) images were obtained from ten healthy volunteers (age-71.6 +/- 7.5 years, mean+/- SD) as they swallowed 5-cc thin liquid barium aliquots. For each swallow, the bolus head and several anatomic landmarks were digitally recorded from the image in which pharyngeal swallow-related hyoid bone elevation began. Vertical distance between the bolus head and the intersection of the tongue base and mandibular ramus (TMI) was computed. Bolus head position at swallow onset ranged from 47.4-mm above to 34.9-mm below the TMI (2.2 +/- 14.4-mm, mean +/- SD). Although the bolus head was below the level of the TMI for the majority of swallows, neither penetration nor aspiration occurred. For individual subjects, mean bolus head position ranged from 25.8 +/- 5.0-mm above to 15.5 +/- 6.5-mm below the TMI. Whereas five of ten subjects initiated the pharyngeal swallow with the bolus head consistently above or consistently below the TMI, five subjects initiated swallowing with the bolus head either above or below the TMI across trials. Older adults commonly initiate thin-liquid swallows with the bolus head well below the TMI without associated penetration or aspiration. Thus, bolus position alone does not differentiate between normal and pathologic swallowing within the healthy elderly. Bolus position at pharyngeal swallow onset can vary substantially from trial to trial within an individual, suggesting that the triggering of swallowing depends on multiple influences.
authors.affiliation: School of Communication Sciences and Disorders, Faculty of Health Sciences, University of Western Ontario, Elborn College, London, Ontario, Canada.
authors.forename: Jennifer R
authors.initials: JR
authors.lastname: Stephen
authors.forename: Donald H
authors.initials: DH
authors.lastname: Taves
authors.forename: Rebecca C
authors.initials: RC
authors.lastname: Smith
authors.forename: Ruth E
authors.initials: RE
authors.lastname: Martin
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001466:Barium Sulfate; D015331:Cohort Studies; D003679:Deglutition / Q000502:physiology*; D003680:Deglutition Disorders / Q000175:diagnosis / Q000453:epidemiology; D005260:Female; D005471:Fluoroscopy / Q000379:methods; D015577:Geriatric Assessment; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008297:Male; D008365:Manometry; D008875:Middle Aged; D009960:Oropharynx / Q000502:physiology*; D012016:Reference Values; D012307:Risk Factors; D012680:Sensitivity and Specificity; D014741:Video Recording
chemical_list: D001466:Barium Sulfate