Objectives: This paper aims to explore whether the Persian-speaking patients of different stages, ranging from mild to moderate, have a deficit in semantic processing by comparing the performance of Alzheimer's patients with that of the healthy individuals. Methods:The subjects of both the groups of Alzheimer's patients and healthy control were matched for age, the state of monolingual or bilingual, and socio-cultural status. In order to assess the semantic processing ability of the subjects, Pekkala's 2004 model was adopted. According to the model, the subjects were required to produce (say) the name of as many as category members of animals as possible within the time limit of 60 seconds. Results:The findings showed that while healthy subjects had an intact semantic processing ability, the AD patients showed weak performance in the five measures of semantic fluency including the number of true linguistic units, the total quantity of words, word size in clusters, the mean cluster size, and the cluster switching.

Introduction: So far, many studies have investigated the extent and nature of the grammatical deficit in aphasia. However, to the best of our knowledge, this research is the first in the Persian language to inspect the comprehension of patients with Broca’s aphasia on diverse syntactically complex structures. Materials and Methods: To scrutinize the impact of task on aphasics’ performance, four age-, education- and gender-matched Persian-speaking patients with Broca’s aphasia were compared with their healthy matched controls regarding the two different tasks of grammatical judgment and figurine act-out task. The structures used to examine the subjects’ performance included agentive passive, subject cleft, object cleft, object relative clause, and object experiencer psychological verbs. Results: Our results which supported the trade-off hypothesis, showed that our subjects generally performed better in grammatical judgment task than in figurine act-out task (P≤0.05). Particularly in the second task, as our inner task comparison, the patients’ problems were more severe in object cleft, object experiencer, and object relative clauses: all structures whose interpretations need more cognitive load. Conclusion: Our findings put more weight on the interactive or constraint-based model of language processing.

Objectives: 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. Methods: 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. Results: 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. Discussion: 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.

Introduction: The production of figurative expressions, particularly idioms, and proverbs, is negatively affected by damage to the left hemisphere and subcortical area of the brain. Alzheimer patients, thanks to the preservation of basal ganglia, can produce these expressions. In contrast, compared to Alzheimer’s patients, Parkinson’s patients cannot produce these expressions due to the malfunction of the basal ganglia. This study attempts to compare the linguistic and cognitive performance of Persian-speaking patients with Alzheimer’s disease, Parkinson’s disease, and healthy counterparts regarding the production and comprehension of these figurative expressions. Materials and Methods: In doing so, by selecting a sample  of participants  composed  of  10 Alzheimer’s patients, 10 Parkinson’s patients, and 10 healthy individuals matched with each other regarding age and education. Then, different tests, including Arizona battery for communication disorders of dementia, famous names, and face test, structured conversation, figurative expression completion, elicitation of response based on situational context, Northridge evaluation of idioms and proverbs in situational context, conventional and figurative expression evaluation were condcuted to analyze their performance. Results: The results of Arizona battery for communication disorders of dementia indicated that Alzheimer’s patients were in the middle stage of the disease while Parkinson’s participants were classified as non-dementia patients. Although the result of the Renown face and name recognition test demonstrated a significant difference between Alzheimer’s patients and the healthy group regarding cognition and confidence levels, the same result was not observed between healthy control and Alzheimer’s patients. Furthermore, in the test of structured conversation, the proportion of produced words by Alzheimer’s patients was more than that of Parkinson’s patients. However, the results of sentence and figurative expression completion tests corroborated the weaker performance of Alzheimer’s patients compared to their Parkinson and healthy counterparts. Furthermore, notwithstanding in the test of Elicitation of response based on Situational Context, Parkinson’s patients performed more poorly than their Alzheimer and healthy counterparts, in the tests of conventional and figurative expression evaluation, Alzheimer’s patients’ pattern of performance was different from that of other groups as they performed more weakly than Parkinson patients. Conclusion: The observed dissociation in the performance of Alzheimer as well as Parkinson’s patients in the linguistic production and comprehension tests shed light on the significant role of the subcortical area of the brain in the production of idioms and proverbs.