The Relationship Between Psychological Factors and Cognitive Function in Patients With Parkinson’s Disease Who Have Chronic Fatigue

Background and Objectives: Cognitive and psychological disorders are among the most debilitating complications of Parkinson’s Disease (PD). Despite the high prevalence of these disorders in patients with PD and the important effect of psychological factors on cognitive factors in other neurological diseases, no study was found on the relationship between psychological factors and cognitive function in patients with PD who have chronic fatigue. The present study was conducted to investigate the relationship between psychological factors and cognitive function in patients with PD and chronic fatigue. Methods: In the present cross-sectional study, a total of 73 patients with PD who had chronic fatigue were selected by non-random convenience sampling method from those visiting Tehran’s rehabilitation centers in 2019. The following questionnaires were used: Fatigue Severity Scale (FSS) for fatigue, Beck’s Depression Inventory for depression, Beck’s Anxiety Inventory for anxiety, and Mini-Mental State Examination (MMSE) and Montreal Cognitive Assessment (MoCA) for cognitive function, as well as Unified Parkinson’s Disease Rating Scale (UPDRS-III) and Pain Visual Analog Scale (Pain VAS). Results: The regression models explained the cognitive function variance by a maximum of 1.43% in MMSE and 8.79% in MoCA. In all stepwise models of cognitive function, anxiety was the strongest predictor of cognitive function followed by age and UPDRS-III score. Conclusion: The results of this study indicated that anxiety as the strongest predictor can affect cognitive function in patients with PD who have chronic fatigue. Hence, therapeutic interventions focusing on psychological factors may be particularly important for improving cognitive function in these patients.