Project description:Background: Cognitive impairment in Parkinson's disease (PD) includes a spectrum varying from Mild Cognitive Impairment (PD-MCI) to PD Dementia (PDD). The main aim of the present study is to evaluate the incidence of PD-MCI, its rate of progression to dementia, and to identify demographic and clinical characteristics which predict cognitive impairment in PD patients. Methods: PD patients from a large hospital-based cohort who underwent at least two comprehensive neuropsychological evaluations were retrospectively enrolled in the study. PD-MCI and PDD were diagnosed according to the Movement Disorder Society criteria. Incidence rates of PD-MCI and PDD were estimated. Clinical and demographic factors predicting PD-MCI and dementia were evaluated using Cox proportional hazard model. Results: Out of 139 enrolled PD patients, 84 were classified with normal cognition (PD-NC), while 55 (39.6%) fulfilled the diagnosis of PD-MCI at baseline. At follow-up (mean follow-up 23.5 ± 10.3 months) 28 (33.3%) of the 84 PD-NC at baseline developed MCI and 4 (4.8%) converted to PDD. The incidence rate of PD-MCI was 184.0/1000 pyar (95% CI 124.7-262.3). At multivariate analysis a negative association between education and MCI development at follow-up was observed (HR 0.37, 95% CI 0.15-0.89; p = 0.03). The incidence rate of dementia was 24.3/1000 pyar (95% CI 7.7-58.5). Out of 55 PD-MCI patients at baseline, 14 (25.4%) converted to PDD, giving an incidence rate of 123.5/1000 pyar (95% CI 70.3-202.2). A five time increased risk of PDD was found in PD patients with MCI at baseline (RR 5.09, 95% CI 1.60-21.4). Conclusion: Our study supports the relevant role of PD-MCI in predicting PDD and underlines the importance of education in reducing the risk of cognitive impairment.
Project description:Cognitive dysfunction is a significant non-motor feature of Parkinson's disease, with the risk of dementia increasing with prolonged disease duration. Multiple cognitive domains are affected, and the pathophysiology cannot be explained by dopaminergic loss alone. Sophisticated neuroimaging techniques can detect the nature and extent of extra-nigral involvement by targeting neurotransmitters, abnormal protein aggregates and tissue metabolism. This review identifies the functional and anatomical imaging characteristics that predict cognitive impairment in PD, the limitations that challenge this process, and the avenues of potential research.
Project description:INTRODUCTION:Identification of factors associated with progression of cognitive symptoms in Parkinson's disease (PD) is important for treatment planning, clinical care, and design of future clinical trials. The current study sought to identify whether prediction of cognitive progression is aided by examining baseline cognitive features, and whether this differs according to stage of cognitive disease. METHODS:Participants with PD in the Pacific Udall Center Clinical Consortium who had longitudinal data available and were nondemented at baseline were included in the study (n = 418). Logistic and Cox regression models were utilized to examine the relationship between cognitive, demographic, and clinical variables with risk and time to progression from no cognitive impairment to mild cognitive impairment (PD-MCI) or dementia (PDD), and from PD-MCI to PDD. RESULTS:Processing speed (OR = 1.05, p = 0.009) and working memory (OR = 1.01, p = 0.03) were associated with conversion to PDD among those with PD-MCI at baseline, over and above demographic variables. Conversely, the primary predictive factor in the transition from no cognitive impairment to PD-MCI or PDD was male sex (OR = 4.47, p = 0.004), and males progressed more rapidly than females (p = 0.01). Further, among females with shorter disease duration, progression was slower than for their male counterparts, and poor baseline performance on semantic verbal fluency was associated with shorter time to cognitive impairment in females but not in males. CONCLUSIONS:This study provides evidence for sex differences in the progression to cognitive impairment in PD, while specific cognitive features become more important indicators of progression with impending conversion to PDD.
Project description:BackgroundCognitive deficit in Parkinson disease (PD) is an important cause of functional disability in these patients and early detection, with sensitive instruments, can contribute to longitudinal monitoring.ObjectiveTo investigate the diagnostic accuracy, sensitivity, and specificity of the Addenbrooke's Cognitive Examination-III in patients with PD, using the comprehensive neuropsychological battery as reference method.MethodsCross-sectional, observational, case-control study.Settingrehabilitation service. A total of 150 patients and 60 healthy controls matched for age, sex, and education. For level I assessment, Addenbrooke Cognitive Examination (ACE-III) was used. Level II assessment used a comprehensive neuropsychological battery of standardized tests for this population. All patients remained in on-state during the study. The diagnostic accuracy of the battery was investigated through the receiver operating characteristic (ROC) analysis.ResultsThe clinical group was divided into 3 subgroups: normal cognition in Parkinson's disease (NC-PD-16%), mild cognitive impairment due to Parkinson's disease (MCI-PD-69.33%), and dementia due to Parkinson's disease (D-PD-14.66%). ACE-III optimal cutoff scores for detecting MCI-PD and D-PD were 85/100 (sensitivity 58.65%, specificity 60%) and 81/100 points (sensitivity 77.27%, specificity 78.33%), respectively. Age was inversely associated with the performance of the scores (totals and domains of the ACE-III), while the level of education had a significantly positive correlation in the performance of these scores.ConclusionsACE-III is a useful battery for assessing the cognitive domains and to differentiate individuals with MCI-PD and D-PD from healthy controls. Future research, in a community setting, is necessary to provide discriminatory capacity of ACE-III in the different severities of dementia.
Project description:IntroductionNo known studies have compared longitudinal characteristics between individuals with incident mild cognitive impairment due to Parkinson's disease (PD-MCI) versus Alzheimer's Disease (AD-MCI).MethodsWe used longitudinal data from the National Alzheimer's Coordinating Center's Uniform Data Set to compare 41 PD-MCI and 191 AD-MCI participants according to their demographics, presence of ≥1 APOE e4 allele, and baseline and change over time in clinical characteristics, neuropsychological test scores, and Clinical Dementia Rating sum of boxes (CDR-SB). Multivariable linear regression models with generalized estimating equations were used to account for clustered data and to test for baseline and longitudinal differences in neuropsychological test scores.ResultsPD-MCI and AD-MCI participants differed by many demographic and clinical characteristics. Significantly fewer PD-MCI participants developed dementia over one year. Compared to AD-MCI participants, PD-MCI participants performed better at baseline and over time on a global measure of cognition (Mini Mental State Exam), memory measures (immediate and delayed Logical Memory), and a language measure (Boston Naming Test), and additionally performed better over time on an attention measure (Digit Span Forward), a language measure (Vegetable List), a processing speed measure (Digit Symbol), and an overall measure of memory and functional impairment (CDR-SB).ConclusionOur study provides further evidence that PD-MCI is clinically distinct from AD-MCI and requires different tools for diagnosis and monitoring clinical progression. More importantly, this study suggests that PD-MCI takes longer to convert into dementia than AD-MCI, findings that require replication by other studies.
Project description:This study aimed to investigate the cortical neural correlates of dementia conversion in Parkinson's disease with mild cognitive impairment (PD-MCI). We classified 112 patients with drug-naïve early stage PD meeting criteria for PD-MCI into either PD with dementia (PDD) converters (n = 34) or nonconverters (n = 78), depending on whether they developed dementia within 4 years of PD diagnosis. Cortical thickness analyses were performed in 34 PDD converters and 34 matched nonconverters. Additionally, a linear discriminant analysis was performed to distinguish PDD converters from nonconverters using cortical thickness of the regions that differed between the two groups. The PDD converters had higher frequencies of multiple domain MCI and amnestic MCI with storage failure, and poorer cognitive performances on frontal/executive, memory, and language function domains than did the nonconverters. Cortical thinning extending from the posterior cortical area into the frontal region was observed in PDD converters relative to nonconverters. The discriminant analysis showed that the prediction model with two cortical thickness variables in the right medial superior frontal and left olfactory cortices optimally distinguished PDD converters from nonconverters. Our data suggest that cortical thinning in the frontal areas including the olfactory cortex is a marker for early dementia conversion in PD-MCI.
Project description:We investigated the efficacy of donepezil for mild cognitive impairment in Parkinson's disease (PD-MCI). This was a prospective, non-randomized, open-label, two-arm study. Eighty PD-MCI patients were assigned to either a treatment or control group. The treatment group received donepezil for 48 weeks. The primary outcome measures were the Korean version of Mini-Mental State Exam and Montreal Cognitive Assessment scores. Secondary outcome measures were the Clinical Dementia Rating, Unified Parkinson's Disease Rating Scale part III, Clinical Global Impression scores. Progression of dementia was assessed at 48-week. Comprehensive neuropsychological tests and electroencephalography (EEG) were performed at baseline and after 48 weeks. The spectral power ratio of the theta to beta2 band (TB2R) in the electroencephalogram was analyzed. There was no significant difference in the primary and secondary outcome measures between the two groups. However, the treatment group showed a significant decrease in TB2R at bilateral frontotemporoparietal channels compared to the control group. Although we could not demonstrate improvements in the cognitive functions, donepezil treatment had a modulatory effect on the EEG in PD-MCI patients. EEG might be a sensitive biomarker for detecting changes in PD-MCI after donepezil treatment.
Project description:BackgroundThere is increasing interest in therapeutic ketosis as a potential therapy for neurodegenerative disorders-in particular, mild cognitive impairment (MCI), Alzheimer's disease (AD), and Parkinson's disease (PD)-following a proof-of-concept study in Parkinson's disease published in 2005.MethodsTo provide an objective assessment of emerging clinical evidence and targeted recommendations for future research, we reviewed clinical trials involving ketogenic interventions in mild cognitive impairment, Alzheimer's disease, and Parkinson's disease reported since 2005. Levels of clinical evidence were systematically reviewed using the American Academy of Neurology criteria for rating therapeutic trials.Results10 AD, 3 MCI, and 5 PD therapeutic ketogenic trials were identified. Respective grades of clinical evidence were objectively assessed using the American Academy of Neurology criteria for rating therapeutic trials. We found class "B" evidence (probably effective) for cognitive improvement in subjects with mild cognitive impairment and subjects with mild-to-moderate Alzheimer's disease negative for the apolipoprotein ε4 allele (APOε4-). We found class "U" evidence (unproven) for cognitive stabilization in individuals with mild-to-moderate Alzheimer's disease positive for the apolipoprotein ε4 allele (APOε4+). We found class "C" evidence (possibly effective) for improvement of non-motor features and class "U" evidence (unproven) for motor features in individuals with Parkinson's disease. The number of trials in Parkinson's disease is very small with best evidence that acute supplementation holds promise for improving exercise endurance.ConclusionsLimitations of the literature to date include the range of ketogenic interventions currently assessed in the literature (i.e., primarily diet or medium-chain triglyceride interventions), with fewer studies using more potent formulations (e.g., exogenous ketone esters). Collectively, the strongest evidence to date exists for cognitive improvement in individuals with mild cognitive impairment and in individuals with mild-to-moderate Alzheimer's disease negative for the apolipoprotein ε4 allele. Larger-scale, pivotal trials are justified in these populations. Further research is required to optimize the utilization of ketogenic interventions in differing clinical contexts and to better characterize the response to therapeutic ketosis in patients who are positive for the apolipoprotein ε4 allele, as modified interventions may be necessary.
Project description:This study examined whether standard cognitive training, tailored cognitive training, transcranial direct current stimulation (tDCS), standard cognitive training?+?tDCS, or tailored cognitive training?+?tDCS improved cognitive function and functional outcomes in participants with PD and mild cognitive impairment (PD-MCI). Forty-two participants with PD-MCI were randomized to one of six groups: (1) standard cognitive training, (2) tailored cognitive training, (3) tDCS, (4) standard cognitive training?+?tDCS, (5) tailored cognitive training?+?tDCS, or (6) a control group. Interventions lasted 4 weeks, with cognitive and functional outcomes measured at baseline, post-intervention, and follow-up. The trial was registered with the Australian New Zealand Clinical Trials Registry (ANZCTR: 12614001039673). While controlling for moderator variables, Generalized Linear Mixed Models (GLMMs) showed that when compared to the control group, the intervention groups demonstrated variable statistically significant improvements across executive function, attention/working memory, memory, language, activities of daily living (ADL), and quality of life (QOL; Hedge's g range?=?0.01 to 1.75). More outcomes improved for the groups that received standard or tailored cognitive training combined with tDCS. Participants with PD-MCI receiving cognitive training (standard or tailored) or tDCS demonstrated significant improvements on cognitive and functional outcomes, and combining these interventions provided greater therapeutic effects.