Evaluation of formation of past tense of regular and irregular verbs in Persian-Speaking Patients with Parkinson's disease

Parkinson’s disease (PD) is a progressive neurodegenerative disease that results in damage to the basal ganglia. (PD) patients suffer from a wide range of motor and cognitive symptoms. Also there is a group of language and grammatical disorders such as failure to understand complex sentences, shortening sentences and removing prepositions and phrases in patient with PD. This study investigates the formation of past tense of regular and irregular verbs and comprehension of passive sentences by Persian-speaking PD patients and compares their behavior with normal speakers.

Twenty patients with PD and 30 healthy subjects, between 60 to 80 participate in this study. All participants were Persianspeaking male and monolingual. We used Mini-Mental State Examiniation (MMSE), Unified Parkinson’s Disease Rating Scale (UPDRS) and Modified Hoehn and Yahr scale for assessing cognitive state in both groups and staging of PD in patients group. Formation of past tense-regular and irregular verbs in both groups were compared by declarative-procedural model.

Our result showed unlike healthy group there is a significant difference between formation of regular and irregular verbs in patients with PD (P=0/023). Also there is a significant difference between both groups in formation of regular verbs (P=0/002). On the basis of the result, we concluded that there is a functional separation between processing of regular and irregular verbs in patient with PD that is not observed in healthy subjects.