The Analysis of Semantic Field in Persian-Speaking Patients With Wernicke’s Aphasia

Wernicke’s aphasia is one of the most prominent focal brain deficits affecting the comprehension abilities of patients while preserving their production abilities. Although a lot of studies in different languages have been conducted to analyze the nature of this deficit, still some controversies exist in this regard. While some research studies attribute this defect to a performance problem, some research highlight competence deficit and hypothesize qualitative problems. This research, considering the lack of sufficient literature in Persian, tries to reconcile this controversy by investigating the nature of the semantic field in Persian-speaking patients with Wernicke’s aphasia and to compare their semantic processing abilities with those of healthy controls.

In doing so, a semantic judgment task was administered to 10 patients with Wernicke’s aphasia and their age- and education-matched controls to recognize different semantic relations between a group of words whose meanings were related to each other in some way or another.

The results showed dissociation in the subjects’ performance. While patients with Wernicke’s aphasia had severe deficits in semantic judgment tasks, healthy control performed very well. This selective performance was also observed in different semantic pairs. Also, patients with Wernicke’s aphasia performed poorly in almost all classes of semantic pairs, but the severity of their problems was more prominent in certain semantic categories.

The findings, in line with a competence deficit hypothesis, suggest that linguistic items are processed in the mental lexicon as a semantic unit. Hence, linguistic items are categorized in a brain network correlating with each other based on different semantic relationships.