Verb Frequency and Density Drive Naming Performance in Primary Progressive Aphasia

Area of Science:

• Neurolinguistics
• Cognitive Neuroscience
• Speech and Language Pathology

Background:

• The Boston Naming Test and Hopkins Action Naming Assessment (HANA) are valuable tools for differentiating semantic (svPPA), logopenic (lvPPA), and non-fluent agrammatic (nfavPPA) variants of primary progressive aphasia (PPA).
• Understanding the specific linguistic challenges faced by each PPA variant is crucial for accurate diagnosis and targeted interventions.

Purpose of the Study:

• To investigate whether lexical variables, including word frequency, semantic density, concreteness, and valency, explain item-level differences in verb naming across PPA variants using the HANA.
• To test hypotheses regarding the differential impact of semantic density, concreteness, and valency on verb naming in svPPA, lvPPA, and nfavPPA.

Main Methods:

• Evaluated 268 patients diagnosed with PPA using the Hopkins Action Naming Assessment (HANA).
• Employed a hierarchical Bayesian regression model to analyze item-level verb naming performance, accounting for repeated measures within participants and items.

Main Results:

• Word frequency, semantic density, and concreteness positively correlated with naming performance, while valency showed a negative correlation.
• Low semantic density significantly impaired verb naming in svPPA and lvPPA.
• nfavPPA patients did not exhibit particular naming difficulties related to verb valency.

Conclusions:

• The combination of lexical dimensions, particularly frequency and semantic density, provides the most accurate prediction of verb naming performance in PPA.
• This study reinforces the utility of the HANA for efficiently assessing verb production deficits in various PPA subtypes.