CHAPTER
It has long ago been determined that adults swallow approximately 600 times daily (1,2). The act of swal- lowing involves more than 30 muscles and nerves and is divided into four phases: oral preparatory, oral, pha- ryngeal, and esophageal (3). (See Box 10.1 [4].)
THE PHYSIOLOGY OF NORMAL
SWALLOWING With age, there is a noted decrease in salivary gland secretion, an increase in mastication required to prepare the food for swallowing, an increase in time to prepare the food bolus, and a decrease in pharyn- geal contractions, delaying the pharyngeal phase of swallowing (5,6). While age-related changes do
BOX 10.1 The Physiology of Normal Swallowing
Oral preparatory phase: This involves seeing, smelling, and recognizing food before opening the mouth to take a bite.
Oral phase: The chewing process during which the tongue scoops food and places it back on the teeth. Food is formed into a bolus and moved to the back of the mouth.
Pharyngeal phase: The larynx lifts and moves forward, vocal folds close, the epiglottis moves to help close the airway, and the soft palate lifts to close the nasal cavity. The pharyngeal muscles move food into the esophagus.
Esophageal phase: The upper esophageal sphincter relaxes and food is moved via peristalsis to the stomach.
Source: Brush J. Recognizing dysphagia at meals. Long-Term Living.
www.ltlmagazine.com/article/recognizing-dyspha- gia-meals. Published September 30, 2007. Accessed January 25, 2016.
10
Etiology and Risks of Swallowing Disorders
affect normal swallow function, an older adult’s swallow is not necessarily an impaired swallow. The act of normal swallowing is relatively well preserved throughout the healthy aging process (7), but presbyphagia— changes in the swallowing process of healthy older adults—does occur (see Box 10.2 [8]). When complications with the swallowing process
do occur, health care professionals need to determine whether the individual has dysphagia, presbyphagia, or other related diagnoses to avoid overdiagnosing and overtreating dysphagia. Eating and swallowing disor- ders may be neurological, mechanical, or functional in their etiology. With the increased threats of acute illness, multiple medications, and any number of age-related conditions, older adults are more vulnera- ble and can cross the line from having a healthy older
BOX 10.2 Age-Related Changes in Normal Swallow Function
Oropharyngeal swallowing changes with aging: ●
slower swallowing ●
delayed protection of airway and upper esophageal sphincter (UES) opening
● bolus adjacent to airway longer ● decreased lingual pressures
Esophageal swallowing changes with aging: ●
● ● ●
longer duration of esophageal peristalsis and amplitude decreases (60–80 years)
diminished esophageal contraction amplitude; function remains intact (80–90 years)
secondary peristalsis frequency diminished increased reflux
Source: Roche V. Precutaneous endoscopic gastrostomy. Clinical care of PEG tubes in older adults. Geriatrics. 2003;58:22-26,28-29.
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