LAUSR

HighlightsAmyloid‐negative lvPPA subjects have a unique linguistic profile.Amyloid‐negative lvPPA has some language features similar to amyloid‐positive.Amyloid‐negative lvPPA also shares language features with agrammatic PPA.The speech of lvPPA can help distinguish amyloid‐negative versus‐positive subjects. Abstract Logopenic primary progressive aphasia (lvPPA) typically results from underlying Alzheimer's disease, but subjects have been reported that do not show beta‐amyloid (A&bgr;) deposition. These subjects do not differ on neurological and speech‐language testing from A&bgr;‐positive lvPPA, but they impressionistically show increased grammatical deficits. We performed a quantitative linguistic analysis of grammatical characteristics in A&bgr;‐negative lvPPA compared to A&bgr;‐positive lvPPA and agrammatic PPA, which is characterized by increased grammatical difficulties. A&bgr;‐negative lvPPA used fewer function words and correct verbs but more syntactic and semantic errors compared to A&bgr;‐positive lvPPA. These measures did not differ between A&bgr;‐negative lvPPA and agPPA. Both lvPPA cohorts showed a higher mean length of utterance, more complex sentences, and fewer nouns than agPPA. A&bgr;‐negative lvPPA subjects appear unique and share linguistic features with both agPPA and A&bgr;‐positive lvPPA. Quantitative language analysis in lvPPA may be able to distinguish those with and without A&bgr; deposition.