Lexical-semantic Properties in Parkinson's Disease with and without Dementia

Dementia has important clinical consequences for patients with PD and their caregivers, which may negatively, affected their daily living activities and quality of life. Previous studies, have investigated the properties and characteristics of the words generated in semantic fluency task by patients with Alzheimer's disease, but this has not been investigated in PD patients yet. This study aimed to investigate if there are possible distinctive features that might differentiate between cognitive decline direct consequence of Idiopathic PD and that of Alzheimer’s type dementia associated with PD. There were six PD patients with dementia, six matched PD patients without dementia and six matched controls participated in this study. The present findings showed that although patients with dementia performed worse than those without dementia on all neuropsychological tests, significant differences were found only on the semantic fluency test and Frontal assessment battery. Furthermore, the present findings showed that patients with dementia produced fewer words in the semantic fluency task than healthy controls did. The words generated by demented patients were longer, less familiar, less typical and acquired later in life than the words produced by healthy controls. These findings might use for clinical application to distinct between PD patients with and without dementia.