Penetration-aspiration scale

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The penetration-aspiration scale (PAS) is a means of grading the severity of penetration or aspiration observed in a videofluoroscopic swallow study and is widely used .

The term aspiration is used for material that passes inferior to the level of the vocal folds. If material enters the larynx but remains above the vocal folds this is called penetration.

The eight point scale was introduced by John C Rosenbek et al. in 1996 in a groundbreaking article .

Classification

  • no penetration or aspiration
  • penetration, contrast remains above the vocal folds, subsequently ejected
  • penetration, contrast remains above the vocal folds, not ejected
  • penetration, contrast contacts vocal folds, subsequently ejected
  • penetration, contrast contacts vocal folds, not ejected
  • aspiration (contrast below vocal folds), subsequently ejected (at least into larynx)
  • aspiration (contrast below vocal folds), not ejected despite effort
  • aspiration (contrast below vocal folds), no effort made to eject