Cognitive Impairment in Parkinson s Disease

Background: Parkinson’s disease (PD) is a progressive neurodegenerative disorder with characteristic clinical motor features combined with non-motor symptoms. Cognitive impairment has a very significant impact on the patient’s quality of life. The risk of developing dementia is six times higher in PD patients than in general population and increases with longer duration of the disease. Objectives: The aim of this study is to assess cognitive impairment in PD patients and its characteristics and to explore the correlation between duration of the disease, its stage, and neuroimaging of the brain. Material and methods: The study involved 64 patients with clinical diagnosis of PD established on the basis of the UKPDS BB criteria. Patients with PD were subdivided into two groups: patients with disease duration under five years and over five years. Participation in the study included taking medical history, collecting information on the course of the disease and its treatment, identification of comorbidities, and neurological examination. A neuropsychological assessment was carried out for all the patients and included: MMSE, CDT, verbal fluency test (both semantic and phonemic tasks) and, in part, the ADAS-cog test. The examination also included the BDI (Beck Depression Inventory) test. CT and MRI scans were performed of PD patients in order to assess atrophy of the brain and hippocampus. Results: Most of the PD patients suffer from visuospatial and semantic fluency dysfunctions. The level of cognitive impairment in PD is dependent on the patient’s age and the motor symptom severity assessed using the H-Y scale. We observed a clear relationship in PD between cognitive impairment and atrophy of the hippocampus, temporal and parietal lobes, and vascular lesion. Conclusion: Cognitive function impairment appears in Parkinson’s patients without diagnosed dementia. The executive functions are especially affected with the level of impairment dependent on the patient’s age and the degree of movement impairment.