Table 2.

Three representative domains of the Progressive Aphasia Severity Scale (PASS) (Sapolsky et al., 2010)

PASS Domain	0 normal	0.5 questionable/very mild impairment	1 mild impairment	2 moderate impairment	3 severe impairment
FLUENCY: Degree to which speech flows easily or is interrupted by hesitations, fillers, pauses; reduced fluency is associated with decreased phrase length and words per minute (WPM)	Normal flow of speech.	Speech contains occasional blank pauses or use of fillers (umm); reduced WPM and/or phrase length.	Speech is in short phrases, interrupted with pauses or groping for words but there are occasional runs of fluent speech.	Dysfluencies in most utterances; phrase length rarely exceeds three words.	Severely dysfluent speech; phrase length rarely exceeds one word. May not speak.
SYNTAX AND GRAMMAR: Use of word forms (run, ran), functor words (the, an), and word order when forming phrases and sentences in most used modality (speech or writing)	No difficulty in the use of grammar and syntax.	Occasional agrammatism or paragrammatism (i.e., odd sentence structure such as, "I my car drive in your house."); may complain it is effortful to combine words into phrases or sentences	Frequent agrammatism; sentence structures are simple; frequent misuse/omission of grammatical words or morphology	Utterances contain mostly content words with rare use of syntactic word groupings, functor words, or morphological markers	Single word utterances or no speech/writing.
SINGLE WORD COMPREHENSION: Ability to understand spoken or written single words	No difficulty understanding single words in conversation or testing.	Occasional difficulty understanding low frequency words (e.g., cork); may question the meaning of words (e.g., "What is a__?").	Displays lack of word comprehension several times in a brief conversation but able to carry on reasonably meaningful conversation.	Understands some high frequency and/or familiar words. Questions the meaning of many words in conversation.	Minimal comprehension of single words.