Do feature importance and feature relevance differentially influence lexical semantic knowledge in individuals with aphasia?

Abstract

Purpose: This study investigated two classifications of semantic features, feature <i>importance</i> and feature <i>relevance</i>, to verify if they differentially influenced lexical semantic knowledge in individuals with aphasia.Methods: A sorting task was utilized with 20 volunteer participants with aphasia to investigate the semantic processing involved in the association of semantic features with their appropriate nouns. A corpus of 18 nouns was displayed in front of each participant in groups of three along with a card containing the word “UNRELATED.” The participants were verbally instructed to sort decks of cards into one of the four designated piles. The semantic features on the cards were rated as <i>high, mid</i>, and <i>low</i> importance and <i>high, mid</i>, and <i>low</i> relevance.Results: The participants sorted <i>high importance</i> features with their nouns more accurately than they did <i>mid</i> and <i>low importance</i> features. Feature <i>relevance</i> did not differentially influence noun-feature association. These results indicated that the ability of individuals with aphasia to associate features with their nouns is influenced by levels of feature importance.Conclusions: Lexical semantic knowledge in individuals with aphasia is influenced by <i>high</i> versus <i>low</i> level of feature importance and the effect does not extend to a <i>mid</i> level of importance. The classification of feature relevance did not differentially influence the ability of individuals with aphasia to associate features with their appropriate nouns. In addition, participants who were less affected by aphasia performed better in the naming and feature comprehension tasks.