Mild cognitive impairment has gained recognition as a construct and a potential prodromal stage to dementia in both Alzheimer's disease and Parkinson's disease (PD). Although mild cognitive impairment has been recognized in the Alzheimer's disease field, it is a relatively more recent topic of interest in PD. Recent advances include the development of diagnostic criteria for PD mild cognitive impairment to provide more uniform definitions for clinical and research use. Studies reveal that mild cognitive impairment in PD is frequent, but also heterogeneous, with variable clinical presentations, differences in its progression to dementia, and likely differences in underlying pathophysiology. Application of the International Parkinson and Movement Disorder Society PD Mild Cognitive Impairment Task Force diagnostic criteria has provided insights regarding cognitive measures, functional assessments, and other key topics that may require additional refinement. Furthermore, it is important to consider definitions of PD mild cognitive impairment in the landscape of other related Lewy body disorders, such as dementia with Lewy bodies, and in the context of prodromal and early-stage PD. This article examines the evolution of mild cognitive impairment in concept and definition, particularly in PD, but also in related disorders such as Alzheimer's disease and dementia with Lewy bodies; the development and application of International Parkinson and Movement Disorder Society PD Mild Cognitive Impairment diagnostic criteria; and insights and future directions for the field of PD mild cognitive impairment. © 2018 International Parkinson and Movement Disorder Society.

The blood-brain barrier (BBB) regulates cerebrovascular permeability and leakage of blood-derived fibrinogen. Dysfunction of the BBB has been associated with cerebral arteriolosclerosis small vessel disease (SVD) and white matter lesions (WML). Furthermore, BBB dysfunction is associated with the pathogenesis of Alzheimer's disease (AD) with the presence of CSF plasma proteins suggested to be a potential biomarker of AD. We aimed to determine if extravascular fibrinogen in the white matter was associated with the development of AD hallmark pathologies, i.e., hyperphosphorylated tau (HPτ) and amyloid-β (Aβ), as well as SVD, cerebral amyloid angiopathy (CAA) and measures of white matter damage. Using human post-mortem brains, parietal tissue from 20 AD and 22 non-demented controls was quantitatively assessed for HPτ, Aβ, white matter damage severity, axonal density, demyelination and the burden of extravascular fibrinogen in both WML and normal appearing white matter (NAWM). SVD severity was determined by calculating sclerotic indices. WML- and NAWM fibrinogen burden was not significantly different between AD and controls nor was it associated with the burden of HPτ or Aβ pathology, or any measures of white matter damage. Increasing severity of SVD was associated with and a predictor of both higher WML- and NAWM fibrinogen burden (all P < 0.05) in controls only. In cases with minimal SVD NAWM fibrinogen burden was significantly higher in the AD cases (P < 0.05). BBB dysfunction was present in both non-demented and AD brains and was not associated with the burden of AD-associated cortical pathologies. BBB dysfunction was strongly associated with SVD but only in the non-demented controls. In cases with minimal SVD, BBB dysfunction was significantly worse in AD cases possibly indicating the influence of CAA. In conclusion, extravascular fibrinogen is not associated with AD hallmark pathologies but indicates SVD, suggesting that the presence of fibrinogen in the CSF is not a surrogate marker for AD pathology.

Currently, the neuropathological diagnosis of Lewy body disease (LBD) may be stated according to several staging systems, which include the Braak Lewy body stages (Braak), the consensus criteria by McKeith and colleagues (McKeith), the modified McKeith system by Leverenz and colleagues (Leverenz), and the Unified Staging System by Beach and colleagues (Beach). All of these systems use semi-quantitative scoring (4- or 5-tier scales) of Lewy pathology (LP; i.e., Lewy bodies and Lewy neurites) in defined cortical and subcortical areas. While these systems are widely used, some suffer from low inter-rater reliability and/or an inability to unequivocally classify all cases with LP. To address these limitations, we devised a new system, the LP consensus criteria (LPC), which is based on the McKeith system, but applies a dichotomous approach for the scoring of LP (i.e., "absent" vs. "present") and includes amygdala-predominant and olfactory-only stages. α-Synuclein-stained slides from brainstem, limbic system, neocortex, and olfactory bulb from a total of 34 cases with LP provided by the Newcastle Brain Tissue Resource (NBTR) and the University of Pennsylvania brain bank (UPBB) were scanned and assessed by 16 raters, who provided diagnostic categories for each case according to Braak, McKeith, Leverenz, Beach, and LPC systems. In addition, using LP scores available from neuropathological reports of LP cases from UPBB (n = 202) and NBTR (n = 134), JT (UPBB) and JA (NBTR) assigned categories according to all staging systems to these cases. McKeith, Leverenz, and LPC systems reached good (Krippendorff's α ≈ 0.6), while both Braak and Beach systems had lower (Krippendorff's α ≈ 0.4) inter-rater reliability, respectively. Using the LPC system, all cases could be unequivocally classified by the majority of raters, which was also seen for 97.1% when the Beach system was used. However, a considerable proportion of cases could not be classified when using Leverenz (11.8%), McKeith (26.5%), or Braak (29.4%) systems. The category of neocortical LP according to the LPC system was associated with a 5.9 OR (p < 0.0001) of dementia in the 134 NBTR cases and a 3.14 OR (p = 0.0001) in the 202 UPBB cases. We established that the LPC system has good reproducibility and allows classification of all cases into distinct categories. We expect that it will be reliable and useful in routine diagnostic practice and, therefore, suggest that it should be the standard future approach for the basic post-mortem evaluation of LP.

Objective

Most investigations of pharmacotherapy for treating Alzheimer's disease focus on patients with mild-to-moderate symptoms, with little evidence to guide clinical decisions when symptoms become severe. We examined whether continuing donepezil, or commencing memantine, is cost-effective for community-dwelling, moderate-to-severe Alzheimer's disease patients.

Methods

Cost-effectiveness analysis was based on a 52-week, multicentre, double-blind, placebo-controlled, factorial clinical trial. A total of 295 community-dwelling patients with moderate/severe Alzheimer's disease, already treated with donepezil, were randomised to: (i) continue donepezil; (ii) discontinue donepezil; (iii) discontinue donepezil and start memantine; or (iv) continue donepezil and start memantine.

Results

Continuing donepezil for 52 weeks was more cost-effective than discontinuation, considering cognition, activities of daily living and health-related quality of life. Starting memantine was more cost-effective than donepezil discontinuation. Donepezil-memantine combined is not more cost-effective than donepezil alone.

Conclusions

Robust evidence is now available to inform clinical decisions and commissioning strategies so as to improve patients' lives whilst making efficient use of available resources. Clinical guidelines for treating moderate/severe Alzheimer's disease, such as those issued by NICE in England and Wales, should be revisited. © 2016 The Authors. International Journal of Geriatric Psychiatry published by John Wiley & Sons Ltd.

The prodromal phase of dementia with Lewy bodies (DLB) includes (1) mild cognitive impairment (MCI), (2) delirium-onset, and (3) psychiatric-onset presentations. The purpose of our review is to determine whether there is sufficient information yet available to justify development of diagnostic criteria for each of these. Our goal is to achieve evidence-based recommendations for the recognition of DLB at a predementia, symptomatic stage. We propose operationalized diagnostic criteria for probable and possible mild cognitive impairment with Lewy bodies, which are intended for use in research settings pending validation for use in clinical practice. They are compatible with current criteria for other prodromal neurodegenerative disorders including Alzheimer and Parkinson disease. Although there is still insufficient evidence to propose formal criteria for delirium-onset and psychiatric-onset presentations of DLB, we feel that it is important to characterize them, raising the index of diagnostic suspicion and prioritizing them for further investigation.

Despite its high prevalence among dementias, Lewy body dementia (LBD) remains poorly understood with a limited, albeit growing, evidence base. The public-health burden that LBD imposes is worsened by overlapping pathologies, which contribute to misdiagnosis, and lack of treatments. For this report, we gathered and analyzed public-domain information on advocacy, funding, research outputs, and the therapeutic pipeline to identify gaps in each of these key elements. To further understand the current gaps, we also conducted interviews with leading experts in regulatory/governmental agencies, LBD advocacy, academic research, and biopharmaceutical research, as well as with funding sources. We identified wide gaps across the entire landscape, the most critical being in research. Many of the experts participated in a workshop to discuss the prioritization of research areas with a view to accelerating therapeutic development and improving patient care. This white paper outlines the opportunities for bridging the major LBD gaps and creates the framework for collaboration in that endeavor. HIGHLIGHTS: A group representing academia, government, industry, and consulting expertise was convened to discuss current progress in Dementia with Lewy Body care and research. Consideration of expert opinion,natural language processing of the literature as well as publicly available data bases, and Delphi inspired discussion led to a proposed consensus document of priorities for the field.

The first Lewy Body Dementia Association (LBDA) Research Centers of Excellence (RCOE) Investigator's meeting was held on December 14, 2017, in New Orleans. The program was established to increase patient access to clinical experts on Lewy body dementia (LBD), which includes dementia with Lewy bodies (DLB) and Parkinson's disease dementia (PDD), and to create a clinical trials-ready network. Four working groups (WG) were created to pursue the LBDA RCOE aims: (1) increase access to high-quality clinical care, (2) increase access to support for people living with LBD and their caregivers, (3) increase knowledge of LBD among medical and allied (or other) professionals, and (4) create infrastructure for a clinical trials-ready network as well as resources to advance the study of new therapeutics.

The Dementia with Lewy Bodies (DLB) Consortium has refined its recommendations about the clinical and pathologic diagnosis of DLB, updating the previous report, which has been in widespread use for the last decade. The revised DLB consensus criteria now distinguish clearly between clinical features and diagnostic biomarkers, and give guidance about optimal methods to establish and interpret these. Substantial new information has been incorporated about previously reported aspects of DLB, with increased diagnostic weighting given to REM sleep behavior disorder and ¹²³iodine-metaiodobenzylguanidine (MIBG) myocardial scintigraphy. The diagnostic role of other neuroimaging, electrophysiologic, and laboratory investigations is also described. Minor modifications to pathologic methods and criteria are recommended to take account of Alzheimer disease neuropathologic change, to add previously omitted Lewy-related pathology categories, and to include assessments for substantia nigra neuronal loss. Recommendations about clinical management are largely based upon expert opinion since randomized controlled trials in DLB are few. Substantial progress has been made since the previous report in the detection and recognition of DLB as a common and important clinical disorder. During that period it has been incorporated into DSM-5, as major neurocognitive disorder with Lewy bodies. There remains a pressing need to understand the underlying neurobiology and pathophysiology of DLB, to develop and deliver clinical trials with both symptomatic and disease-modifying agents, and to help patients and carers worldwide to inform themselves about the disease, its prognosis, best available treatments, ongoing research, and how to get adequate support.

BACKGROUND: Multiple System Atrophy is a rare neurodegenerative disease with alpha-synuclein aggregation in glial cytoplasmic inclusions and either predominant olivopontocerebellar atrophy or striatonigral degeneration, leading to dysautonomia, parkinsonism, and cerebellar ataxia. One prior genome-wide association study in mainly clinically diagnosed patients with Multiple System Atrophy failed to identify genetic variants predisposing for the disease. OBJECTIVE: Since the clinical diagnosis of Multiple System Atrophy yields a high rate of misdiagnosis when compared to the neuropathological gold standard, we studied only autopsy-confirmed cases. METHODS: We studied common genetic variations in Multiple System Atrophy cases (N = 731) and controls (N = 2898). RESULTS: The most strongly disease-associated markers were rs16859966 on chromosome 3, rs7013955 on chromosome 8, and rs116607983 on chromosome 4 with P-values below 5 × 10-6 , all of which were supported by at least one additional genotyped and several imputed single nucleotide polymorphisms. The genes closest to the chromosome 3 locus are ZIC1 and ZIC4 encoding the zinc finger proteins of cerebellum 1 and 4 (ZIC1 and ZIC4). INTERPRETATION: Since mutations of ZIC1 and ZIC4 and paraneoplastic autoantibodies directed against ZIC4 are associated with severe cerebellar dysfunction, we conducted immunohistochemical analyses in brain tissue of the frontal cortex and the cerebellum from 24 Multiple System Atrophy patients. Strong immunohistochemical expression of ZIC4 was detected in a subset of neurons of the dentate nucleus in all healthy controls and in patients with striatonigral degeneration, whereas ZIC4-immunoreactive neurons were significantly reduced inpatients with olivopontocerebellar atrophy. These findings point to a potential ZIC4-mediated vulnerability of neurons in Multiple System Atrophy. © 2022 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

The APOE locus is strongly associated with risk for developing Alzheimer's disease and dementia with Lewy bodies. In particular, the role of the APOE ε4 allele as a putative driver of α-synuclein pathology is a topic of intense debate. Here, we performed a comprehensive evaluation in 2466 dementia with Lewy bodies cases versus 2928 neurologically healthy, aged controls. Using an APOE-stratified genome-wide association study approach, we found that GBA is associated with risk for dementia with Lewy bodies in patients without APOE ε4 (P = 6.58 × 10-9, OR = 3.41, 95% CI = 2.25-5.17), but not with dementia with Lewy bodies with APOE ε4 (P = 0.034, OR = 1.87, 95%, 95% CI = 1.05-3.37). We then divided 495 neuropathologically examined dementia with Lewy bodies cases into three groups based on the extent of concomitant Alzheimer's disease co-pathology: pure dementia with Lewy bodies (n = 88), dementia with Lewy bodies with intermediate Alzheimer's disease co-pathology (n = 66) and dementia with Lewy bodies with high Alzheimer's disease co-pathology (n = 341). In each group, we tested the association of the APOE ε4 against the 2928 neurologically healthy controls. Our examination found that APOE ε4 was associated with dementia with Lewy bodies + Alzheimer's disease (P = 1.29 × 10-32, OR = 4.25, 95% CI = 3.35-5.39) and dementia with Lewy bodies + intermediate Alzheimer's disease (P = 0.0011, OR = 2.31, 95% CI = 1.40-3.83), but not with pure dementia with Lewy bodies (P = 0.31, OR = 0.75, 95% CI = 0.43-1.30). In conclusion, although deep clinical data were not available for these samples, our findings do not support the notion that APOE ε4 is an independent driver of α-synuclein pathology in pure dementia with Lewy bodies, but rather implicate GBA as the main risk gene for the pure dementia with Lewy bodies subgroup.