3. Aspiration
Aspiration is the term used to describe the passage of foreign material (including food and liquid), through the true vocal cords into the trachea. When this happens, the expected reflex response is a cough due to excitation of recurrent laryngeal nerve receptors. Patients with dysphagia may present with aspiration leading to either an immediate, delayed or absent cough response. Additionally, the cough may or may not be effective at ejecting material back into the hypopharynx. The severity of aspiration is determined using a subjective impression of the amount of material aspirated (e.g., trace, moderate or severe amounts) and quantification of the depth of aspiration and response in terms of coughing. The 8-point Penetration-Aspiration Scale [40] has become the standard metric for aspiration severity (see Table 3), and captures both the depth of airway invasion (e.g., above versus below the true vocal folds), and whether or not material is ejected to a higher anatomical level of safety or remains at its lowest position. A score of 8 represents “silent aspiration” in which material is aspirated below the true vocal folds without any overt clinical signs. During a videofluoroscopic examination, separate evaluations of aspiration should be made for each bolus consistency (i.e., thin, nectar-thick, honey-thick or spoon-thick barium). An important purpose beyond completion of standardized bolus challenges in the videofluoroscopy is the exploration of the effectiveness of bolus texture modification or behavioral maneuvers in limiting aspiration.