A 65-year-old woman with a brainstem stroke demonstrates poor bolus formation, weak lip closure, and weak buccal tension. On the basis of these findings, which swallowing phase is most likely affected?

• A. Oral preparatory phase
• B. Oral phase
• C. Pharyngeal phase
• D. Esophageal phase

Answer: (A)

The main idea is where the bolus is formed and held together for swallowing. The oral preparatory phase is the stage in which the lips seal to keep saliva from dripping, and the buccal muscles and other facial muscles work to gather and moisten the food, forming a cohesive bolus. When there is weak lip closure and reduced buccal tension, the ability to seal the mouth and compress the bolus is compromised, so the bolus cannot be formed properly. That’s exactly what’s described here, pointing to disruption of the oral preparatory stage.

The pharyngeal phase and the esophageal phase involve swallowing after the bolus is formed and propelled or after it passes through the esophagus, respectively, and the signs given don’t point to those stages. The oral phase would involve moving a formed bolus toward the back of the mouth, which is a separate step from forming the bolus in the mouth.