Patterns of decline in naming and semantic knowledge in primary progressive aphasia

ABSTRACT

Background: Individuals with primary progressive aphasia (PPA) and their caregivers want to know what to expect so that they can plan support appropriately. The ability to predict decline in naming and semantic knowledge, and advise individuals with PPA and their caregivers regarding future planning, would be invaluable clinically.

Aims: The aims of this study were to investigate patterns of decline in naming and semantic knowledge in each of the clinical variants of PPA (logopenic variant PPA, lvPPA; nonfluent agrammatic PPA, nfaPPA; and semantic variant PPA, svPPA) and to examine the effects of other variables on rate of decline. We hypothesized that speech-language rehabilitation, higher education, and higher baseline test scores would be associated with slower decline, and older age with faster decline.

Methods and Procedures: A total of 94 participants with PPA underwent language testing, including 36 participants with lvPPA, 31 participants with nfaPPA, and 27 participants with svPPA. All participant groups were similar in age and education. We focused on decline on three tests: the short form of the Boston Naming Test (BNT), the Hopkins Assessment of Naming Actions (HANA), and the short form of the Pyramids and Palm Trees Test (PPTT).

Outcome and Results: Across language tests, the most precipitous rates of decline (loss of points per month) occurred in nfaPPA, followed by svPPA, then lvPPA. Female sex, longer symptom duration, higher baseline test score, and speech-language rehabilitation were associated with slower decline.

Conclusions: PPA variants were distinguishable by rapidity of decline, with nfaPPA having the most precipitous decline. As hypothesized, higher baseline test scores and speech-language rehabilitation were associated with slower decline. Surprisingly, age and education were not important prognostically for individuals in this study. Further study of prognostically-relevant variables in PPA is indicated in this population.

KEYWORDS:

• Primary progressive aphasia
• nonfluent agrammatic primary progressive aphasia
• semantic variant primary progressive aphasia
• logopenic variant primary progressive aphasia
• language symptoms

Acknowledgments

This work was made possible by the National Institutes of Health (National Institute of Deafness and Communication Disorders) and the National Institute on Aging through award R01 DC011317, and by National Institutes of Health (National Institute of Deafness and Communication Disorders) through awards R01 DC005375 and K99 DC015554. We also would like to acknowledge support for the statistical analysis from the National Center for Research Resources and the National Center for Advancing Translational Sciences (NCATS) of the National Institutes of Health through Grant Number UL1 TR001079. We gratefully acknowledge this support. The content is solely the responsibility of the authors and does not necessarily represent the views the National Institutes of Health.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the NIH (National Center for Research Resources and the National Center for Advancing Translational Sciences (NCATS)) [1UL1TR001079]; NIH (National Institute of Deafness and Communication Disorders) [K99DC015554, R01 DC011317, R01 DC005375]; National Institute on Aging [R01 DC011317].