Lexical Search and Retrieval in Aphasia: A Computational Analysis of Semantic Fluency

Area of Science:

• Cognitive Neuroscience
• Linguistics
• Computational Psychology

Background:

• Semantic fluency tasks reveal how people access interconnected conceptual-lexical networks.
• Few studies have examined semantic fluency retrieval patterns in people with aphasia (PWA).

Purpose of the Study:

• To investigate lexical information use in semantic memory search in healthy controls and PWA using computational modeling.
• To assess how semantic memory search metrics relate to other measures of aphasia and semantic processing.

Main Methods:

• Employed computational modeling to analyze semantic memory search strategies.
• Compared retrieval patterns in healthy controls (n=47) and PWA (n=53).
• Administered aphasia battery measures, including semantic processing tests.

Main Results:

• PWA produced fewer items and showed less phonological similarity between consecutive items compared to controls.
• Controls primarily used phonology within local clusters; PWA used phonology within clusters and during switches.
• Impaired verbal semantic comprehension in PWA correlated with increased phonological similarity, suggesting a compensatory mechanism.

Conclusions:

• Individuals with aphasia exhibit difficulties adapting search cues in semantic fluency tasks.
• Computational modeling effectively characterizes semantic memory search in both neurotypical and language-impaired populations.