Swallowing involves two basic and fundamental issues. The first issue is airway protection, and the other is bolus or food transport. When one eats food and it "goes down the wrong way", this is an obvious example of one's airway not being protected properly. In addition to airway protection is, of course, having one's food winding up in the right place- the stomach.

All types of swallowing testing, including endoscopic tests and x-ray tests of swallowing, look at how things move. However, these types of exams don't look at airway protection rigorously. A new technique that I developed known as FEESST or Flexible Endoscopic Evaluation of Swallowing with Sensory Testing, is the first swallowing test to do both.


Why Do We Study Swallowing Problems?

Swallowing problems are extremely common affecting millions of people every year. An excellent example of the common nature of this problem is demonstrated by looking at swallowing problems after stroke. There are approximately 400,000 new strokes per year in the United States with an incidence of dysphagia ranging from 35%- 47% (1, 2). The primary reason patients die after stroke is due to pulmonary complications, specifically aspiration pneumonia. Approximately 50,000 people die each year as a result of aspiration pneumonia after stroke (3, 4). While there are many reasons patients develop aspiration pneumonia, several studies have demonstrated a strong relationship between dysphagia and aspiration pneumonia. Dysphagia often results in difficulty handling food and secretions, a consequence of which is contamination of the lungs (5, 6, 7, 8, 9).

Aspiration pneumonia is a significant cause of chronic illness in United States nursing homes and the most common reason for residents of nursing homes to be transferred to a hospital (10, 11). In American nursing homes the prevalence of aspiration pneumonia has been reported as high as 8% (12, 13, 14, 15).

The cost of treating a single episode of pneumonia in a hospital, including intravenous antibiotics, a stay in an intensive care unit, with or without respiratory support, averages $19,000 (16). While the mortality from aspiration pneumonia can approach 40%, it is not the first episode of pneumonia that causes an individual to succumb, rather it is recurrent pneumonia over a several year period that is so deadly and so costly (2). The goal of therapy for the patient with dysphagia is therefore to improve the quality of life while at the same time keeping the instances of aspiration pneumonia to a minimum.

Silent aspiration is defined as foreign material entering the trachea or lungs without an outward sign of coughing or respiratory difficulty by the patient. Silent aspiration is a clinical condition that can be present in patients with dysphagia who have a variety of diagnoses, including stroke, degenerative neurological disease, chronic obstructive pulmonary disease and intracranial trauma (17). While the etiology of silent aspiration is multifactorial, one of the likely etiologies of silent aspiration is diminution of laryngopharyngeal airway protective reflexes, commonly seen after stroke (18).

Silent aspiration has been shown to be particularly common in dysphagic patients who are on ventilators (19). In a study of several hundred patients with dysphagia, it was shown that approximately 30% of patients referred for a dysphagia evaluation in a large tertiary care medical center were noted to be silently aspirating during an endoscopic evaluation of swallowing (17). The insidious nature of silent aspiration, and its prevalence, which necessarily cannot be detected during a non-instrumentation evaluation of swallowing, underscores the importance of directly visualizing the laryngopharynx during a swallowing evaluation.

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