# Penetration-Aspiration Scale (PAS): plain-language definition

Canonical: [https://followyourswallow.com/glossary/penetration-aspiration-scale](https://followyourswallow.com/glossary/penetration-aspiration-scale)

An 8-point rating scale clinicians use to describe how far food or liquid traveled toward the airway during a single swallow, and what happened next.

## In plain language

The Penetration-Aspiration Scale, usually shortened to PAS, is a rating system clinicians use when reviewing a recorded swallow study. It was introduced in 1996 by Rosenbek and colleagues in the journal Dysphagia, and it has 8 points.

Two things decide which number a swallow receives: how far the food or liquid traveled toward or into the airway, and whether it was cleared back out. A score of 1 means material does not enter the airway. A score of 8 means material passed below the vocal folds and no effort was made to eject it.

You may see PAS numbers listed next to specific sips or bites in a report, because each swallow is scored on its own. A number describes one swallow at one moment during the test. It is not an overall grade of you, and it is not a diagnosis by itself.


## Why a clinician looks at this

The scale gives clinicians a shared, consistent vocabulary for describing what they saw on the video, so that different clinicians reviewing the same swallow are more likely to describe it the same way and so that change over time can be tracked. What any particular score means in your situation is something only your own clinician can explain, in the context of the whole study.

## Sources

- [PMC: Reflections on Clinical and Statistical Use of the Penetration-Aspiration Scale](https://pmc.ncbi.nlm.nih.gov/articles/PMC5608795/)


Source checked: 2026-08-07

Clinical review: SLP review in progress

## Safety

This is a general definition, not an interpretation of a person's report. Ask the clinician who performed the study what the term means for that person.