Mild cognitive impairment in Parkinson’s disease: the Parkinson’s disease cognitive study (PACOS)

Abstract

Approximately 30% of Parkinson's disease (PD) patients show impaired cognitive performance, which is suggestive of Mild Cognitive Impairment (MCI), representing a predictor of dementia, especially when present at diagnosis. The objective of the study was to evaluate the frequency and clinical predictors of MCI in a large hospital-based cohort of PD patients. We collected cross-sectional data from the Parkinson's disease cognitive impairment study (PACOS), a multicenter study involving two Movement Disorder centers, which are located in south Italy. The PD subjects were diagnosed according to the UK Brain Bank criteria and they underwent an extensive neuropsychological assessment. PD-MCI was diagnosed according to the Movement Disorder Society task force criteria for MCI. PD severity was evaluated in accordance with the Unified PD Rating Scale-Motor Examination (UPDRS-ME) and the Hoehn and Yahr scales. The study included 659 PD patients (57.5% men; mean age 67.0 ± 9.7 years), with a mean disease duration of 3.8 ± 4.6 years and a mean UPRDS-ME score of 25.8 ± 12.3. PD-MCI was diagnosed in 261 (39.6%) subjects and in 82 (31.7%) of 259 newly diagnosed patients (disease duration ≤ 1 year). An amnestic MCI multidomain phenotype was the most frequent MCI subtype (39.1% of the overall sample and 43.9% in newly diagnosed PD). A positive significant association between MCI, age and motor scores was found at multivariate logistic regression analysis, while a negative association was observed between educational level and MCI. In conclusion and in agreement with the literature data, the prevalence of MCI recorded in the PACOS sample was approximately 40 and 32% amongst newly diagnosed patients.

Prevalence and Clinical Aspects of Mild Cognitive Impairment in Parkinson's Disease: A Meta‐Analysis

“…The prevalence rate computed here (40%) was very close to the value reported in previous cross‐sectional and longitudinal studies where PD‐MCI was identified by MDS criteria, but higher than the value reported in studies where MCI was defined by other clinical criteria . This difference underlines the clinical relevance of adopting uniform MDS criteria to identify PD‐MCI accurately.…”

“…A total of 9 of 25 studies found that patients with PD‐MCI took higher LEDD than patients without PD‐MCI; our meta‐analysis confirmed this association (Supplementary Material 5; Table ), with a significant and positive ES (= 0.25). The heterogeneity among the studies was significant and moderate, but sensitivity analysis indicated stability of ES level, and there was no publication bias.…”

“…Of 21 studies, 8 revealed that PD‐MCI patients had higher H&Y stages than patients without PD‐MCI (Supplementary Material 5). Our meta‐analytic study showed that PD‐MCI patients had higher scores on the H&Y (Table ), with a significant and positive ES (= 0.33).…”

“…The relation of PD‐MCI with TD and PIGD motor subtypes were assessed in 5 studies (Supplementary Material 3). Our meta‐analysis revealed that the prevalence of PD‐MCI was higher in the PIGD subtype (46%; n = 587; 95% CI = 41–51; Q = 4.80; P = 0.309; I 2 = 16.63%) when compared with the TD subtype (35%; n = 357; 95% CI = 30–40; Q = 3.27; P = 0.513; I 2 = 0%).…”

“…Mild cognitive impairment associated with Parkinson's disease (PD‐MCI) is a risk factor for the development of dementia associated with PD; thus, the early identification of patients with PD‐MCI in clinical routine might allow to deploy appropriate pharmacological and nonpharmacological interventions (ie, cognitive training). Until now, several prospective and cross‐sectional studies provided mixed data on the prevalence rate of PD‐MCI, ranging from about 20% to 70% . Inconsistencies across studies can be partly explained by several methodological factors, such as the heterogeneity in diagnostic criteria for MCI, patient samples, neuropsychological batteries, and different levels of diagnosis (ie, Abbreviated Assessment, Level I or Comprehensive Assessment, Level II, according to the Movement Disorder Society [MDS]).…”