Table 8.

The 4-level Categorical Penetration-Aspriation Scale (PAS)

Level	Description
A	Normal function or an effective response to the material penetration into the supraglottic space (correspondent to the original PAS score of 1, 2, and 4)
B	Presence of material in the laryngeal vestibule after the swallow, extending to the true vocal folds level, but not below (correspondent to the original PAS score of 3, 5, and 6)
C	Failure of protection mechanisms in the presence of some recurrent laryngeal nerve sensory integrity (correspondent to the original PAS score of 7)
D	Impairment of effective cough responses to aspiration and sensory stimulations (correspondent to the original PAS score of 8)

Note: ^aAdapted with permission from Steele CM, Grace-Martin K. Reflections on clinical and statistical use of the penetration-aspiration scale. Dysphagia. 2017;32(5):601–616. (http://creativecommons.org/licenses/by/4.0/).⁷³