Evaluation of the Cognitive Impairments and Depressive Symptoms in Patients with Parkinson's Disease: A Case-Control Study from Iran

Abstract Background Parkinson's disease is a progressive neurodegenerative disease and the second most common neurological disease in the world, which usually affects people mainly in later years of life. Cognitive impairments and depressive symptoms are important symptoms in these patients that are associated with a poor prognosis. The study will focus on the original data regarding the cognitive impairments and depressive symptoms in patients with Parkinson's disease and control group. Methods In a case-control study, a total of 100 Parkinson's patients who were hospitalized in Rouhani Hospital and 200 non-Parkinson's people(control group) from Amirkola Health and aging project(AHAP) Marras et al., Babol, Iran were enrolled between September 2019 to February 2020. Data were collected by simple random sampling. Data were collected using a four-part questionnaire, including demographic characteristics, Unified Parkinson Disease Rating Scale (UPDRS), Modified Hoehn and Yahr staging Scale (MHYSS), Mini-Mental State Examination (MMSE) and Geriatric Depression Scale (GDS). P-value less than 0.05 was considered as significant Results A total of 300 persons were enrolled in the study. The mean age of Parkinson's patients and non-Parkinson's people was 70.34 ± 7.76 and 70.87 ± 7.59 years, respectively. The mean MMSE score in Parkinson's and non-Parkinson's people was 24.80 ± 4.53 and 25.40 ± 3.1, respectively (p = 0.182). The mean GDS score in Parkinson's and non-Parkinson's people was 7.06 ± 4.06 and 4.31 ± 3.47, respectively (p =  0.001). There was a statistically significant relationship between depressive symptoms and cognitive impairments with disease severity (p = 0.022 and p = 0.012, respectively). In addition, variables, such as age and the education level were associated with cognitive impairments (p = 0.001 and p = 0.021, respectively), but these variables were not significantly associated with depressive symptoms (p = 0.843 and p = 0.411, respectively). There was a significant relationship between depressive symptoms and cognitive impairment in Parkinson's patients and the control group (p = 0.001 and p = 0.003, respectively). Conclusions Cognitive impairments and depressive symptoms were significantly associated with an increase in the severity of Parkinson's disease, and also, depressive symptoms in Parkinson's patients was associated with an increase in cognitive impairments.