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Semantic interference during object naming in agrammatic and logopenic primary progressive aphasia (PPA)
Cynthia K Thompson1, Soojin Cho, Charis Price
1Department of Communication Sciences and Disorders, Northwestern University, United States. ckthom@northwestern.edu
Individuals with primary progressive aphasia (PPA) show prolonged semantic interference during object naming compared to healthy speakers. This suggests subtle semantic processing deficits contribute to anomia in PPA.
Area of Science:
- Neuroscience
- Psycholinguistics
- Neurology
Background:
- Primary progressive aphasia (PPA) is a neurodegenerative condition affecting language.
- Anomia, or word-finding difficulty, is a common symptom in PPA.
- Understanding the underlying semantic processing deficits is crucial for PPA management.
Purpose of the Study:
- To investigate the temporal dynamics of semantic interference in object naming for individuals with PPA.
- To compare semantic interference patterns between agrammatic PPA (PPA-G) and logopenic PPA (PPA-L) subtypes and healthy controls.
- To explore the relationship between semantic interference abnormalities and brain atrophy in PPA.
Main Methods:
- Utilized a semantic interference paradigm with related and unrelated stimuli.
- Presented stimuli at various stimulus onset asynchronies (SOAs): -1000, -500, -100, and 0 ms.
- Assessed reaction times (RTs) in 21 PPA participants (8 PPA-G, 13 PPA-L) and 17 healthy controls.
Main Results:
- All groups exhibited semantic interference (SI) at SOAs of -500, -100, and 0 ms.
- Both PPA groups demonstrated a greater magnitude of SI compared to controls across all tested SOAs.
- PPA-L and some PPA-G participants showed SI even at -1000 ms, indicating abnormal semantic interference resolution.
Conclusions:
- PPA subtypes exhibit altered temporal processing of semantic information during object naming.
- Impaired semantic interference resolution in PPA correlates with left hemisphere cortical atrophy in semantic processing regions.
- Subtle semantic mapping deficits may underlie anomia in non-semantic variants of PPA.
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