ABSTRACT
Background
The majority of patients with primary progressive aphasia (PPA) can be distinguished into one of three variants: semantic, non-fluent/agrammatic, or logopenic. However, many do not meet criteria for any one variant.
Aim
To identify aspects of cognitive-linguistic performance that yield an early unclassifiable PPA designation that predicted the later emergence of a given variant.
Methods & Procedures
Of 256 individuals with PPA evaluated, 19 initially were unclassifiable and later met criteria for a variant. Receiver operating characteristic curves were used to evaluate the binary ability of a given task to predict eventual classification as a given variant. Tasks with a high area under the curve were examined using regression analyses to determine their ability to predict variant.
Outcomes & Results
High mean predictive value was observed for multiple naming assessments targeting nouns and verbs. The Boston Naming Test (BNT) was the only test that, in isolation, resulted in a significant model and high classification accuracy.
Conclusions
Although naming impairment is common across PPA variants, very low initial BNT scores emerged as a uniquely accurate basis for predicting eventual semantic variant, and normal BNT scores predicted eventual nonfluent/agrammatic variant. High performance on picture-verb verification was useful in identifying future lvPPA.
Author Contributions
MDS & AEH designed the study. All authors contributed to data acquisition. DCT, BLB, & MDS aggregated the data for analysis. MDS completed the analysis, then drafted the manuscript. All authors provided insight into interpretation of the results and read and revised the manuscript for clarity.
Disclosure Statement
The authors report there are no competing interests to declare.
Data Availability Statement
Data are available upon reasonable request from the authors.
This work is supported by National Institutes of Health/National Institute on Deafness and Other Communication Disorders (NIH/NIDCD): R01 DC011317 and P50 DC014664.