The (Martin-Harris et al., 2007 study showed progressively deeper progression of the 5mL liquid bolus with progressively older subjects. At the onset of maximal hyoid motion (the onset of the pharyngeal response and the starting point for measuring stage transition or pharyngeal delay time), the mean age at which the head of the bolus tended to be at the level of the intersection of the mandibular ramus with the tongue base was about 48 years (looking at their figures-not the raw data), at the vallecular pit it was age about 60, hypopharynx = ~70, and pyriform sinuses was about 72 or 3. However (and a huge however), the ranges for each age group were very wide (meaning that the range of age at which bolus head was at the various sites at swallow onset included individuals between about 40 and 70 years). Interestingly in the second swallow, all of the "pyriform sinus" swallows occurred in patients 80 and older, if I am reading this correctly.
This study also plotted pharyngeal delay time and the plot shows confirmation of a definite lengthening in pharyngeal response onset with progressive aging.
This study is published in JSLHR (50 (3): 585) which is available to all ASHA members online (Martin-Harris et al., 2007)
James L. Coyle
University of Pittsburgh
and response from Bonnie Martin-Harris, PhD:
Dear Jim,
Thank you for citing our work and for your complete summary. I do want to point out the following that we believe was one of the most interesting
findings:
"There was, however, one 91-year-old who demonstrated this "timely and safe" position relative to the onset of the swallow. More than 25% of our sample exhibited a bolus head location in the vallecular pits at the onset of hyoid motion. The youngest of these was 26 years old, and the oldest was 89 years old. Thirteen of our participants demonstrated a bolus head location in the hypopharynx superior to the pyriform sinuses at the onset of the pharyngeal swallow. This position was represented by the young (the youngest individual in our sample was
26 years of age) and the old (the oldest individual in our sample was 97 years of age)."
There is some normal variation across ages. Clinicians must understand this variation and can only recognize the threat of related swallowing difficulties via careful evaluation of all functional components of the oropharyngeal swallowing mechanism.
Great to see this dynamic discussion.
Bonnie
Bonnie Martin-Harris, Ph.D., CCC-SLP, BRS-S Director, MUSC Evelyn Trammell Institute for Voice and Swallowing Associate Professor, Otolaryngology-Head and Neck Surgery Medical University of South Carolina
135 Rutledge Avenue
PO Box 250550
Charleston, SC 29425
Phone: (843) 792-7162
Fax: (843) 792-0546