Event sequence variability in healthy swallowing: building on previous findings

Area of Science:

• Physiology
• Biomechanics
• Speech and Hearing Sciences

Background:

• Previous research identified stereotyped event sequences in healthy swallowing.
• Kendall, Leonard, and McKenzie (20XX) established a common swallowing event order.
• Variability in swallowing event sequencing is a known phenomenon.

Purpose of the Study:

• To investigate overall event sequencing during swallowing in young, healthy adults.
• To examine the sequence of four specific paired events during swallowing.
• To compare findings with previous research on swallowing kinematics.

Main Methods:

• Lateral videofluoroscopy protocol with 16 swallows per participant.
• Manipulations included bolus volume, barium density, bolus viscosity, and swallow cueing.
• Analysis focused on the order of 12 key swallowing events.

Main Results:

• Arytenoid movement precedes upper esophageal sphincter (UES) opening.
• Maximum hyolaryngeal approximation occurs after UES opening.
• Previous findings on pharyngeal constriction and UES opening timing were not replicated; the common sequence from Kendall et al. occurred infrequently.

Conclusions:

• Healthy swallowing exhibits variable event sequencing.
• Some paired events demonstrate obligatory sequencing, while the overall sequence is less predictable than previously reported.
• Bolus properties and swallow cues did not fully explain discrepancies with prior studies.