Lexical semantic activation in persons with Aphasia

Abstract

Lexical semantic activation (LSA) is defined as retrieval of the most appropriate word from the lexicon. LSA is accomplished through three steps, conceptual activation, lexical node activation and phoneme retrieval and can be tested through a variety of tasks including priming task. LSA is found to be defective in persons with aphasia; it can be manifested as storage deficit or access deficit. Storage deficit is a condition where there is a total degradation of items in the lexicon and access deficits, and on the other hand is a condition where the items in the lexicon are intact but access to these items is restricted. Persons with access deficits can have problems concerning to lexical node activation or phoneme retrieval and can be tapped through semantic judgment and lexical decision task respectively. The present study aimed to study lexical semantic activation in persons with Broca’s aphasia, anomic aphasia and neurologically healthy individuals. Lexical decision task and semantic judgement task was administered on the participants. Statistically significant difference was seen for persons with Broca’s aphasia and persons with anomic aphasia. No difference was seen for neurologically healthy individuals. Persons with Broca’s aphasia performed well on semantic judgement indicating that the lexical node activation would be intact while persons with anomic aphasia performed well on lexical decision task, showing that the phonological encoding was effective. The findings also pin pointed the defective mechanisms in these variants of aphasia.