There are changes that occur in swallow function that are associated with healthy aging that do not result in dysphagia. The swallow changes that are a result of aging:
Laryngeal Penetration: Shallow laryngeal penetration, when material enters the laryngeal vestibule but does not reach the vocal folds, is a normal finding in all age groups. It’s more frequent at both ends of the lifespan, in infancy and in the elderly. Therefore, older adults will often have shallow laryngeal penetration, particularly with liquid boluses.
Slowed Swallow Response: Studies with healthy older adults show the swallow response changing with age. The swallow response has a later onset, is slower, and lasts longer across bolus types. The result is longer pharyngeal dwell times (e.g. food or liquid reaching the vallecula or even the pyriform sinuses before the swallow response triggers).
Reduced Sensation: Many elderly men and women report changes in taste, specifically in taste acuity. With age, we lose taste bud density and, perhaps more importantly, retronasal olfaction. The olfactory sensations, received as we chew and manipulate food, augment our perception of taste. Reduced olfaction causes taste loss, which can contribute to dehydration, reduced variety in diet, and weight loss.
Speech-Language Pathologists face the dilemma of distinguishing between these normal changes in swallowing and actual dysfunction. The following concepts may help indicate dysphagia:
Consistency: Normal penetration (and even aspiration) occurs inconsistently. For example, the patient who demonstrates laryngeal penetration on all thin liquid swallows is more likely to have dysphagia.
Depth: Normal laryngeal penetration is typically shallow. Penetration that reaches the level of the vocal folds is an irregular finding and should be identified as dysphagia.
Clearance: Normal laryngeal penetration is cleared spontaneously. Material that pools in the larynx and is not cleared is more likely to be aspirated. This swallow should be considered disordered.