Clinical Characterization of Parkinson's Disease Patients With Cognitive Impairment

Abstract

Cognitive impairment is one of the most frequent and disabling non-motor symptoms in Parkinson's disease (PD) and encompasses a continuum from mild cognitive impairment (PD-MCI) to dementia (PDD). The risk factors associated with them are not completely elucidated. To characterize the presence and clinical presentation of PD-MCI and PDD in patients with idiopathic PD, examining motor and non-motor features and determining factors associated with cognitive impairment. Multi-center, cross-sectional study in 298 PD patients that underwent clinical (Hoehn and Yahr staging [HY] and Clinical Impression of Severity Index for Parkinson’s Disease [CISI-PD]), neurological (Scales for Outcomes in Parkinson’s Disease [SCOPA]-Motor), neuropsychological (MiniMental State Examination [MMSE], SCOPA-Cognition [SCOPA-Cog], Frontal Assessment Battery [FAB] and Clinical Dementia Rating Scale [CDR]), neuropsychiatric (SCOPA-Psychiatric complications [SCOPA-PC], SCOPA-Psychosocial [SCOPA-PS] and Hospital Anxiety and Depression Scale [HADS] ) and Health-related Quality of Life (PDQ-8) assessment. Movement Disorders Society criteria were applied to classify patients as normal cognition (NC), PD-MCI and PDD. The association between variables was explored using multivariate binary and multinomial logistic regression models. Seventy-two (24.2%) patients were classified as NC, 82 (27.5%) as PD-MCI and 144 (48.3%) as PDD. These last two groups reported more psychosocial problems related with the disease (mean SCOPA-PS 16.27 and 10.39, respectively), compared with NC (7.28) and lower quality of life outcomes (PDQ-8 48.98 and 28.42, respectively) compared to NC (19.05). The logistic regression analysis showed that both cognitive impaired groups had a more severe stage of PD measured by Hoehn and Yahr (odds ratio for MCI-PD, OR 2.45, 95% confidence interval, CI 1.22-4.90, OR for PDD 2.64, 95%CI 1.17-5.98). Specifically, age (OR 1.30, 95%CI 1.16-1.47), years of education (OR 0.91, 95%CI 0.83-0.99), disease duration (OR 1.19, 95%CI 1.07-1.32), HADS-D (OR 1.20, 95% CI 1.06-1.35) and hallucinations (OR 2.98, 95%CI 1.16-7.69) were related to PDD. Cognitive impairment in PD is associated with more severe disease stage, resulting in a global, neuropsychiatric, psychosocial and quality of life deterioration. This study provides a better understanding of the great impact that cognitive impairment has within the natural history of PD and its relationship with the rest of motor and non-motor symptoms in the disease.