Dementia Syndrome Research Articles

The six brain-specific TAU isoforms and their role in Alzheimer's disease and related neurodegenerative dementia syndromes.

Alternative splicing of the human MAPT gene generates six brain-specific TAU isoforms. Imbalances in the TAU isoform ratio can lead to neurodegenerative diseases, underscoring the need for precise control over TAU isoform balance. Tauopathies, characterized by intracellular aggregates of hyperphosphorylated TAU, exhibit extensive neurodegeneration and can be classified by the TAU isoforms present in pathological accumulations. A comprehensive review of TAU and related dementia syndromes literature was conducted using PubMed, Google Scholar, and preprint server. While TAU is recognized as key driver of neurodegeneration in specific tauopathies, the contribution of the isoforms to neuronal function and disease development remains largely elusive. In this review we describe the role of TAU isoforms in health and disease, and stress the importance of comprehending and studying TAU isoforms in both, physiological and pathological context, in order to develop targeted therapeutic interventions for TAU-associated diseases. MAPT splicing is tightly regulated during neuronal maturation and throughout life. TAU isoform expression is development-, cell-type and brain region specific. The contribution of TAU to neurodegeneration might be isoform-specific. Ineffective TAU-based therapies highlight the need for specific targeting strategies.

Abstract P333: Plasma Proteins, Structural Brain Reserve, and Onset of Alzheimer’s Disease: Proteome-Wide Mendelian Randomization

Introduction: While the emergence of amyloid-clearing treatments for Alzheimer’s disease is promising, the identification of additional therapeutic options for Alzheimer’s disease and related dementia syndromes (AD/ADRD) remains urgent. Plasma proteins represent a class of actionable drug targets AD/ADRD treatment. Yet, the role of the blood proteome in influencing structural brain reserve, and consequently, cognitive performance and the development of AD, remains elusive. Hypothesis: Plasma proteins may causally associate with changes in structural brain reserve and cognition phenotypes. Methods: We conducted proteome-wide Mendelian randomization (MR) to identify potentially causal associations of plasma proteins with changes in brain reserve, proxied by brain imaging-derived phenotypes (IDPs), cognitive performance, and AD onset. Genetic instruments for plasma proteins were previously developed by integrating summary data from five genome-wide association studies (GWASs) of plasma proteome. Summary statistics from large GWASs of 12 AD-associated IDPs (N=33,224), cognitive performance (N=257,841), and two AD cohorts (IGAP consortium, N=63,926, and FinnGen study, N=309,154) are obtained to perform two-sample MR. Causal estimates from two AD outcomes are meta-analyzed to improve statistical power. Correction for multiple testing and sensitivity analyses are performed. Results: Among 956 proteins with genetic instruments that satisfied MR assumptions, genetically determined levels of 14 plasma proteins were associated with at least one of the 10 AD-related IDPs at a false discovery rate of 5%. Six of these proteins were associated with white matter hyperintensities, an IDP known to be involved in cognitive decline. In addition, 26 plasma proteins were associated with cognitive performance, and four were causally linked to AD. Notably, four identified proteins were associated with structural brain reserve and either cognition or AD. Specifically, ADAM12, CREB3L4, and UROS were associated with distinct IDPs and cognitive performance, while TMEM106B, a protein that forms age-dependent amyloid filaments, was associated with increased hippocampal tail volume and AD. Conclusions: This study identified potential causal plasma proteins underlying structural brain reserve, cognitive performance, and AD, offering insights into the molecular etiology of these conditions and potential targets for drug development.

Disinhibition in dementia related to reduced morphometric similarity of cognitive control network.

Disinhibition is one of the most distressing and difficult to treat neuropsychiatric symptoms of dementia. It involves socially inappropriate behaviours, such as hypersexual comments, inappropriate approaching of strangers and excessive jocularity. Disinhibition occurs in multiple dementia syndromes, including behavioural variant frontotemporal dementia, and dementia of the Alzheimer's type. Morphometric similarity networks are a relatively new method for examining brain structure and can be used to calculate measures of network integrity on large scale brain networks and subnetworks such as the salience network and cognitive control network. In a cross-sectional study, we calculated morphometric similarity networks to determine whether disinhibition in behavioural variant frontotemporal dementia (n = 75) and dementia of the Alzheimer's type (n = 111) was associated with reduced integrity of these networks independent of diagnosis. We found that presence of disinhibition, measured by the Neuropsychiatric Inventory Questionnaire, was associated with reduced global efficiency of the cognitive control network in both dementia of the Alzheimer's type and behavioural variant frontotemporal dementia. Future research should replicate this transdiagnostic finding in other dementia diagnoses and imaging modalities, and investigate the potential for intervention at the level of the cognitive control network to target disinhibition.

The Single Toxin Origin of Alzheimer's Disease and Other Neurodegenerative Disorders Enables Targeted Approach to Treatment and Prevention.

New data suggest that the aggregation of misfolded native proteins initiates and drives the pathogenic cascade that leads to Alzheimer's disease (AD) and other age-related neurodegenerative disorders. We propose a unifying single toxin theory of brain neurodegeneration that identifies new targets and approaches to the development of disease-modifying treatments. An extensive body of genetic evidence suggests soluble aggregates of beta-amyloid (Aβ) as the primary neurotoxin in the pathogenesis of AD. New insights from fluid biomarkers, imaging, and clinical studies provide further evidence for the decisive impact of toxic Aβ species in the initiation and progression of AD. Understanding the distinct roles of soluble and insoluble amyloid aggregates on AD pathogenesis has been the key missing piece of the Alzheimer's puzzle. Data from clinical trials with anti-amyloid agents and recent advances in the diagnosis of AD demonstrate that the driving insult in biologically defined AD is the neurotoxicity of soluble Aβ aggregates, called oligomers and protofibrils, rather than the relatively inert insoluble mature fibrils and amyloid plaques. Amyloid oligomers appear to be the primary factor causing the synaptic impairment, neuronal stress, spreading of tau pathology, and eventual cell death that lead to the clinical syndrome of AD dementia. All other biochemical effects and neurodegenerative changes in the brain that are observed in AD are a response to or a downstream effect of this initial toxic insult by oligomers. Other neurodegenerative disorders follow a similar pattern of pathogenesis, in which normal brain proteins with important biological functions become trapped in the aging brain due to impaired clearance and then misfold and aggregate into neurotoxic species that exhibit prion-like behavior. These aggregates then spread through the brain and cause disease-specific neurodegeneration. Targeting the inhibition of this initial step in neurodegeneration by blocking the misfolding and aggregation of healthy proteins has the potential to slow or arrest disease progression, and if treatment is administered early in the course of AD and other neurodegenerative disorders, it may delay or prevent the onset of clinical symptoms.

Phenotypically concordant distribution of pick bodies in aphasic versus behavioral dementias

Pick’s disease (PiD) is a subtype of the tauopathy form of frontotemporal lobar degeneration (FTLD-tau) characterized by intraneuronal 3R-tau inclusions. PiD can underly various dementia syndromes, including primary progressive aphasia (PPA), characterized by an isolated and progressive impairment of language and left-predominant atrophy, and behavioral variant frontotemporal dementia (bvFTD), characterized by progressive dysfunction in personality and bilateral frontotemporal atrophy. In this study, we investigated the neocortical and hippocampal distributions of Pick bodies in bvFTD and PPA to establish clinicopathologic concordance between PiD and the salience of the aphasic versus behavioral phenotype. Eighteen right-handed cases with PiD as the primary pathologic diagnosis were identified from the Northwestern University Alzheimer’s Disease Research Center brain bank (bvFTD, N = 9; PPA, N = 9). Paraffin-embedded sections were stained immunohistochemically with AT8 to visualize Pick bodies, and unbiased stereological analysis was performed in up to six regions bilaterally [middle frontal gyrus (MFG), superior temporal gyrus (STG), inferior parietal lobule (IPL), anterior temporal lobe (ATL), dentate gyrus (DG) and CA1 of the hippocampus], and unilateral occipital cortex (OCC). In bvFTD, peak neocortical densities of Pick bodies were in the MFG, while the ATL was the most affected in PPA. Both the IPL and STG had greater leftward pathology in PPA, with the latter reaching significance (p < 0.01). In bvFTD, Pick body densities were significantly right-asymmetric in the STG (p < 0.05). Hippocampal burden was not clinicopathologically concordant, as both bvFTD and PPA cases demonstrated significant hippocampal pathology compared to neocortical densities (p < 0.0001). Inclusion-to-neuron analyses in a subset of PPA cases confirmed that neurons in the DG are disproportionately burdened with inclusions compared to neocortical areas. Overall, stereological quantitation suggests that the distribution of neocortical Pick body pathology is concordant with salient clinical features unique to PPA vs. bvFTD while raising intriguing questions about the selective vulnerability of the hippocampus to 3R-tauopathies.

No (true) right to die: barriers in access to physician-assisted death in case of psychiatric disease, advanced dementia or multiple geriatric syndromes in the Netherlands

Even in the Netherlands, where the practice of physician-assisted death (PAD) has been legalized for over 20 years, there is no such thing as a ‘right to die’. Especially patients with extraordinary requests, such as a wish for PAD based on psychiatric suffering, advanced dementia, or (a limited number of) multiple geriatric syndromes, encounter barriers in access to PAD. In this paper, we discuss whether these barriers can be justified in the context of the Dutch situation where PAD is legally permitted for those who suffer unbearably and hopelessly as a result of medical conditions. Furthermore, we explore whether there are options to address some of the barriers or their consequences, both within the Dutch legal framework or by adjusting the legal framework, and whether these options are feasible. We conclude that although there are insufficient arguments to overrule the doctor’s freedom of conscience in the Netherlands, there are ways to address some of the barriers, mainly by offering support to doctors that would be willing to support a request. Moreover, we believe it is morally required to reduce or mitigate where possible the negative consequences of the barriers for patients, such as the long waiting time for those who suffer from psychiatric disorders, because it is unlikely the adjustments suggested to the system will ensure reasonable access for these patient groups.

Altered cerebellar and caudate gray-matter volumes and structural covariance networks preceding dual cognitive and mobility impairments in older people.

The neuroanatomical changes driving both cognitive and mobility impairments, an emerging preclinical dementia syndrome, are not fully understood. We examined gray-matter volumes (GMVs) and structural covariance networks (SCNs) abnormalities in community-based older people preceding the conversion to physio-cognitive decline syndrome (PCDS). Voxel-wise brain GMV and established SCNs were compared between PCDS and non-PCDS converters. The study included 343 individuals (60.2±6.9 years, 49.6% men) with intact cognitive and mobility functions. Over an average 5.6-year follow-up, 116 transitioned to PCDS. Identified regions with abnormal GMVs in PCDS converters were over cerebellum and caudate, which served as seeds for SCNs establishment. Significant differences in cerebellum-based (to right frontal pole and left middle frontal gyrus) and caudate-based SCNs (to right caudate putamen, right planum temporale, left precentral gyrus, right postcentral gyrus, and left parietal operculum) between converters and nonconverters were observed. This study reveals early neuroanatomic changes, emphasizing the cerebellum's role, in dual cognitive and mobility impairments. Neuroanatomic precursors of dual cognitive and mobility impairments are identified. Cerebellar GMV reductions and increased right caudate GMV precede the onset of PCDS. Altered cerebellum- and caudate-based SCNs drive PCDS transformation. This research establishes a foundation for understanding PCDS as a specific dementia syndrome.

Disrupted social perception in frontotemporal dementia and Alzheimer's disease – Associated cognitive processes and clinical implications

BackgroundSocial perception refers to the ability to adapt and update one's behaviour in accordance with the current context and provides the foundation for many complex social and emotional interactions. Alterations in social cognition are a hallmark of the behavioural variant of frontotemporal dementia (bvFTD), yet the capacity for social perception in this syndrome remains unclear. MethodsWe examined social perception in 18 bvFTD and 13 Alzheimer's disease (AD) patients, in comparison with 17 healthy older controls, using a social perception task derived from the Dewey Story Test. Participants also completed a comprehensive neuropsychological battery and carers provided ratings of behavioural and neuropsychiatric changes. Results: Overall, bvFTD and AD performance diverged significantly from control ratings on the social perception task, however, no significant difference was found between patient groups. Standardised values relative to the mean control rating revealed considerable variability within the patient groups in terms of the direction of deviation, i.e., over- or under-rating the vignettes relative to healthy controls (range z-scores = −1.79 to +1.63). Greater deviation from control ratings was associated with more pronounced memory (p = .007) and behavioural (p = .009) disturbances in bvFTD; whilst social perception performance correlated exclusively with verbal fluency in AD (p = .003). ConclusionsSocial perception is comparably disrupted in bvFTD and AD, yet likely reflects the differential breakdown of distinct cognitive processes in each dementia syndrome. Our findings have important clinical implications for the development of targeted interventions to manage disease-specific changes in social perception in dementia.

Demographic, clinical, biomarker, and neuropathological correlates of posterior cortical atrophy: an international cohort study and individual participant data meta-analysis

Posterior cortical atrophy is a rare syndrome characterised by early, prominent, and progressive impairment in visuoperceptual and visuospatial processing. The disorder has been associated with underlying neuropathological features of Alzheimer's disease, but large-scale biomarker and neuropathological studies are scarce. We aimed to describe demographic, clinical, biomarker, and neuropathological correlates of posterior cortical atrophy in a large international cohort. We searched PubMed between database inception and Aug 1, 2021, for all published research studies on posterior cortical atrophy and related terms. We identified research centres from these studies and requested deidentified, individual participant data (published and unpublished) that had been obtained at the first diagnostic visit from the corresponding authors of the studies or heads of the research centres. Inclusion criteria were a clinical diagnosis of posterior cortical atrophy as defined by the local centre and availability of Alzheimer's disease biomarkers (PET or CSF), or a diagnosis made at autopsy. Not all individuals with posterior cortical atrophy fulfilled consensus criteria, being diagnosed using centre-specific procedures or before development of consensus criteria. We obtained demographic, clinical, biofluid, neuroimaging, and neuropathological data. Mean values for continuous variables were combined using the inverse variance meta-analysis method; only research centres with more than one participant for a variable were included. Pooled proportions were calculated for binary variables using a restricted maximum likelihood model. Heterogeneity was quantified using I2. We identified 55 research centres from 1353 papers, with 29 centres responding to our request. An additional seven centres were recruited by advertising via the Alzheimer's Association. We obtained data for 1092 individuals who were evaluated at 36 research centres in 16 countries, the other sites having not responded to our initial invitation to participate to the study. Mean age at symptom onset was 59·4 years (95% CI 58·9-59·8; I2=77%), 60% (56-64; I2=35%) were women, and 80% (72-89; I2=98%) presented with posterior cortical atrophy pure syndrome. Amyloid β in CSF (536 participants from 28 centres) was positive in 81% (95% CI 75-87; I2=78%), whereas phosphorylated tau in CSF (503 participants from 29 centres) was positive in 65% (56-75; I2=87%). Amyloid-PET (299 participants from 24 centres) was positive in 94% (95% CI 90-97; I2=15%), whereas tau-PET (170 participants from 13 centres) was positive in 97% (93-100; I2=12%). At autopsy (145 participants from 13 centres), the most frequent neuropathological diagnosis was Alzheimer's disease (94%, 95% CI 90-97; I2=0%), with common co-pathologies of cerebral amyloid angiopathy (71%, 54-88; I2=89%), Lewy body disease (44%, 25-62; I2=77%), and cerebrovascular injury (42%, 24-60; I2=88%). These data indicate that posterior cortical atrophy typically presents as a pure, young-onset dementia syndrome that is highly specific for underlying Alzheimer's disease pathology. Further work is needed to understand what drives cognitive vulnerability and progression rates by investigating the contribution of sex, genetics, premorbid cognitive strengths and weaknesses, and brain network integrity. None.

Fractal Analysis in Neurodegenerative Diseases.

Neurodegenerative diseases are defined by progressive nervous system dysfunction and death of neurons. The abnormal conformation and assembly of proteins is suggested to be the most probable cause for many of these neurodegenerative disorders, leading to the accumulation of abnormally aggregated proteins, for example, amyloid β (Aβ) (Alzheimer's disease and vascular dementia), tau protein (Alzheimer's disease and frontotemporal lobar degeneration), α-synuclein (Parkinson's disease and Lewy body dementia), polyglutamine expansion diseases (Huntington disease), or prion proteins (Creutzfeldt-Jakob disease). An aberrant gain-of-function mechanism toward excessive intraparenchymal accumulation thus represents a common pathogenic denominator in all these proteinopathies. Moreover, depending upon the predominant brain area involvement, these different neurodegenerative diseases lead to either movement disorders or dementia syndromes, although the underlying mechanism(s) can sometimes be very similar, and on other occasions, clinically similar syndromes can have quite distinct pathologies. Non-Euclidean image analysis approaches such as fractal dimension (FD) analysis have been applied extensively in quantifying highly variable morphopathological patterns, as well as many other connected biological processes; however, their application to understand and link abnormal proteinaceous depositions to other clinical and pathological features composing these syndromes is yet to be clarified. Thus, this short review aims to present the most important applications of FD in investigating the clinical-pathological spectrum of neurodegenerative diseases.

A novel MAPT variant (E342K) as a cause of familial progressive supranuclear palsy.

MAPT variants are a known cause of frontotemporal dementia and Parkinsonian syndrome, of which progressive supranuclear palsy syndrome (PSP) is a rare manifestation. To report a novel MAPT variant in a PSP pedigree with autosomal dominant inheritance pattern, and to produce a literature review of PSP patients with MAPT variants. A comprehensive clinical, genetic, and molecular neuroimaging investigation was conducted on a 61 years-old female proband diagnosed with PSP. We also collected the clinical presentation data and history of the patient's pedigree, and performed further genetic analysis of 4 relatives, from two generations, with and without symptoms. The proband exhibited typical clinical manifestation of PSP. A cranial MRI revealed midbrain atrophy, and an FDG-PET scan suggested hypo-metabolic changes in caudate nucleus, left prefrontal lobe, both temporal poles, and midbrain. 18F-florzolo-tau-PET revealed tau-protein deposits in the thalamus and brainstem bilaterally. A gene test by whole-exome sequencing identified a novel MAPT variant [NM_005910.6, exon 11, c.1024G > A (p.E342K)], and the same variant was also identified in one affected relative and one asymptomatic relative, a probable pre-symptomatic carrier. The PSP pedigree caused by the novel MAPT (E342K) variant, expanded the mutational spectrum of MAPT.

Experience of using the combined drug Mioreol in patients with Alzheimer's disease and mixed dementia

The aim of the study was to evaluate the clinical efficacy, safety, and tolerability of a fixed-dose combination of donepezil and memantine (Mioreol) in patients with Alzheimer's disease (AD) and AD with cerebrovascular pathology. 497 patients with moderate to severe dementia, average age 75.4+6.81 years, received Mioreol (donepezil 10 mg+memantine 20 mg). Treatment efficacy was assessed using the MMSE, clock drawing, Sandoz Clinical Geriatric Scale, and Clinical Global Impressions after 3 months of therapy. All adverse events during treatment were recorded. The transition to Mioreol was accompanied by a reliable improvement in cognitive functions, emotional-behavioral indicators and neuropsychiatric status in general. Mioreol demonstrated clinical efficacy, safety and good tolerability in patients with AD and AD with cerebrovascular pathology with moderate to severe dementia syndrome.

Language impairments in Alzheimer´s disease: What changes can be found between mild and moderate stages of the disease?

ObjectiveTo investigate how language deteriorates over the Alzheimer's Disease course. MethodsA cross-sectional, observational study was carried out. 35 patients diagnosed with dementia due to AD using the NINCDS-ARDRA criteria and undergoing treatment for AD with a therapeutic dose of acetylcholinesterase inhibitors were assessed by the Boston Diagnostic Aphasia Examination (BDAE). The sample comprised 15 patients with mild AD (MMSE > 23, CDR = 0 or 0.5‒1.0) and 20 patients with moderate AD (MMSE = 13‒23, CDR = 2). The results for the 2 groups on all language tasks were compared. ResultsA statistically significant difference was found between the mild and moderate AD groups for total score on the BDAE (95% CI 47.10‒114.08, t = 5.0, DF = 21, p = 0.000*), as well as on several tasks involving oral and writing comprehension, language oral expression and writing. ConclusionThe study results showed major changes in the moderate stage. Also, the decline in language performance correlated with the worsening of dementia syndrome, independently of sociodemographic variables.

AI-assisted quantification of hypothalamic atrophy in amyotrophic lateral sclerosis by convolutional neural network-based automatic segmentation

The hypothalamus is a small structure of the brain with an essential role in metabolic homeostasis, sleep regulation, and body temperature control. Some neurodegenerative diseases such as amyotrophic lateral sclerosis (ALS) and dementia syndromes are reported to be related to hypothalamic volume alterations. Despite its crucial role in human body regulation, neuroimaging studies of this structure are rather scarce due to work-intensive operator-dependent manual delineations from MRI and lack of automated segmentation tools. In this study we present a fully automatic approach based on deep convolutional neural networks (CNN) for hypothalamic segmentation and volume quantification. We applied CNN of U-Net architecture with EfficientNetB0 backbone to allow for accurate automatic hypothalamic segmentation in seconds on a GPU. We further applied our approach for the quantification of the normalized hypothalamic volumes to a large neuroimaging dataset of 432 ALS patients and 112 healthy controls (without the ground truth labels). Using the automated volumetric analysis, we could reproduce hypothalamic atrophy findings associated with ALS by detecting significant volume differences between ALS patients and controls at the group level. In conclusion, a fast and unbiased AI-assisted hypothalamic quantification method is introduced in this study (whose acceptance rate based on the outlier removal strategy was estimated to be above 95%) and made publicly available for researchers interested in the conduction of hypothalamus studies at a large scale.

Hearing symptom profiles in Alzheimer’s disease and frontotemporal dementia

AbstractBackgroundHearing loss has emerged as a marker of cognitive decline and potential treatment target in dementia, however the symptom profiles that characterise hearing impairment in different dementia syndromes are poorly characterised. Beyond sound detection, these diseases impair aspects of auditory perception that are crucial for communication in daily life. Here we addressed changes in everyday hearing function in Alzheimer’s disease and frontotemporal dementia syndromes, using standardised auditory symptom questionnaires completed by patients’ caregivers.MethodPrimary caregivers for patients with Alzheimer’s disease (n = 20), logopenic variant primary progressive aphasia (n = 8), nonfluent variant primary progressive aphasia (n = 13), semantic variant primary progressive aphasia (n = 13) and behavioural variant frontotemporal dementia (n = 18) completed the Hearing Impairment Impact – Significant Other Profile, adapted Amsterdam Inventory for Auditory Disability and Khalfa Hyperacusis questionnaires. The Amsterdam Inventory for Auditory Disability was also completed by 15 healthy age‐matched individuals. No participant had a past history of significant otological disease.ResultScores on the Hearing Impairment Impact – Significant Other Profile and Khalfa Hyperacusis Questionnaire respectively demonstrated greater carer burden and increased sensitivity to sound in the behavioural variant frontotemporal dementia group compared with the Alzheimer’s disease group. On the Amsterdam Inventory for Auditory Disability, multi‐domain hearing difficulties were endorsed for the behavioural variant frontotemporal dementia and primary progressive aphasia groups relative to healthy controls, and total scores in the logopenic and semantic variant primary progressive aphasia groups were significantly worse than both the healthy control and Alzheimer’s disease groups. Syndromic groups showed differentiable hearing profiles across hearing domains.ConclusionMajor dementia syndromes have distinct profiles of everyday hearing difficulty, and patients with frontotemporal dementia and progressive aphasia syndromes may have particularly marked (albeit often unrecognised) changes in their hearing. These findings should motivate the development of bespoke auditory tests to assess central hearing function and personalised hearing management strategies in these diseases.

The complex relationship between anticholinergic medication, frailty, and hospitalization in patients with early‐stage dementia

AbstractBackgroundAnticholinergic medications are associated with frailty and hospitalization in patients with dementia. It is unclear if anticholinergic burden mediates the relationship between frailty and hospitalization or if specific dementia syndromes moderate the direct and indirect relationships between these three factors.MethodWe analyzed electronic health record and claims data for member‐patients diagnosed with dementia with Lewy bodies (DLB), Alzheimer’s disease (AD), or vascular dementia (VD) from an integrated healthcare system in the U.S. between October 2015 and August 2022. The Anticholinergic Cognitive Burden Scale (ACB), Claims‐based Frailty Index (frail ≥0.20), and number of hospital admissions were calculated for the 12‐month period prior to dementia diagnosis. Patient demographics, ACB score, frailty status, and hospitalization frequency were compared between dementia syndromes. Baron and Kenny regression‐based method was used to evaluate if ACB is a mediator between frailty and hospitalization. DLB, AD, and VD were included as interactions with ACB and frailty in stratified mediation models to determine if dementia syndrome moderated the relationship. Significant interaction terms indicate a moderating effect of dementia syndrome. All models included patient age and sex as covariates.ResultWe identified 3166 patients (DLB n = 175; AD n = 2478; VD n = 513). Approximately 23% of patients with DLB were prescribed 5+ anticholinergic medications (17.2% with VD; 9.9% with AD; p&lt;.001). Two or more hospitalizations were documented in 12.5% of patients with VD (10.3% with DLB; 5.5% with AD; p&lt;.001). The ACB score was 3.7 greater for patients with frailty compared to those without (3.2, 4.4, p&lt;.001). The relationship between frailty and hospitalization was mediated by ACB (higher ACB was associated with increased utilization; Table 1). A diagnosis of AD or VD moderated the indirect relationship between frailty and hospitalization, but the specific dementia syndrome did not moderate the path between ACB and hospitalization (Table 2; Figure 1).ConclusionIn the year prior to dementia diagnosis, frailty was associated with a higher number of anticholinergic medications, which, in turn, was associated with a greater number of hospitalizations. A diagnosis of VD increased the expected rates of hospitalization for frail patients, while an AD diagnosis decreased the magnitude of the association between frailty and hospitalization.

Disparities in neuropsychiatric symptom clusters across dementia diagnoses within Lewy body dementia syndromes and Alzheimer’s dementia

AbstractBackgroundBehavioral clusters may differ in intensity and frequency across dementia syndromes and according to genetic variants.MethodsConsecutive outpatients with probable dementia with Lewy bodies (fourth consensus report of the DLB Consortium), Parkinson’s disease dementia (PDD, Movement Disorder Society Task Force), or late‐onset Alzheimer’s dementia (AD, National Institute on Aging/Alzheimer’s Association, rs7412&amp;rs429358 genotyped with TaqMan® Real‐Time PCR technology) were recruited (2010‐2018) and assessed for demographic features and scores on a 15‐item Clock Drawing Test (CDT), Mini‐Mental State Examination (MMSE), Index of Independence in Activities of Daily Living (ADL), Lawton’s Scale for Instrumental Activities of Daily Living, Clinical Dementia Rating (CDR) and Zarit Caregiver Burden Interview. According to the Neuropsychiatric Inventory, affective (anxiety,apathy,dysphoria,euphoria), hyperactive (aberrant motor behavior,agitation,disinhibition,irritability), and psychotic (delusions,hallucinations) clusters were associated with cognitive, functional and caregiver burden scores, and compared according to dementia diagnoses, p&lt;0.05.ResultsAll had similar education (p = 0.205): DLB (n = 38;57.9%♀), PDD (n = 14;64.3%♀), APOE‐ε4 carriers with AD (n = 117;72.6%♀), APOE‐ε4 non‐carriers with AD (n = 108;63.0%♀). Patients with AD used cholinesterase inhibitors (p = 0.004) and Memantine (p&lt;0.0001) more often, had higher CDT (p = 0.027) and ADL (p&lt;0.001) scores, and lower caregiver burden (p = 0.022);other score differences were non‐significant among groups. APOE‐ε4 carriers with AD had lower affective scores (p&lt;0.0001), while APOE‐ε4 non‐carriers with AD had lower psychotic scores (p&lt;0.0001);hyperactive scores were similar among groups (p = 0.146). Affective scores were associated with caregiver burden and inversely associated with MMSE scores only in AD, while inversely associated with functionality in DLB and AD;they were also associated with functionality and inversely associated with CDR Sum‐of‐Boxes scores in PDD. Hyperactive scores were inversely associated with functionality in all groups, while associated with cognitive scores in DLB, and inversely in PDD and AD;they were also associated with caregiver burden in DLB and AD, and inversely in PDD. Psychotic scores were associated with CDR Sum‐of‐Boxes scores in PDD and AD, while associated with caregiver burden and inversely with cognition and functionality in all groups.ConclusionsThe affective and hyperactive clusters have divergent associations with clinical features across dementia syndromes, while the psychotic cluster is most consistently associated with worsened cognition, functionality and caregiver burden. APOE‐ε4 carrier status may affect cluster intensity in AD.

Biofluid activity and levels of the angiotensin‐converting enzyme may translate into distinct neuropsychiatric symptoms associated with cerebrospinal fluid amyloid‐beta effects and tauopathy in dementia with Lewy bodies and Alzheimer’s dementia

AbstractBackgroundAmyloid‐β‐degrading enzymes such as the angiotensin‐converting enzyme (ACE‐1) might be surrogates of the amyloid‐β load in the brain potentially triggering tauopathy and behavioral features in dementia.MethodsConsecutive outpatients with probable dementia with Lewy bodies (fourth consensus report of the DLB Consortium) were paired with outpatients with late‐onset Alzheimer’s dementia (AD, National Institute on Aging – Alzheimer’s Association) by sex, Clinical Dementia Rating and Mini‐Mental State Examination scores, and with cognitively healthy controls by sex and age (±1 year). Behavioral symptoms were assessed by way of the Neuropsychiatric Inventory. APOE genotyping (rs7412&amp;rs429358) was undertaken with TaqMan® Real‐Time PCR technology, while conventional PCR was used for the ACE insertion/deletion polymorphism. Cerebrospinal fluid (CSF) amyloid‐β42, amyloid‐β38, ACE‐1, tau and phospho‐tau Thr181 were quantified with enzyme‐linked immunosorbent assays, whereas CSF and plasma ACE‐1 activities were measured using a fluorescence method. Adjusted general linear models were used to examine relationships between log‐transformed behavioral symptoms and biomarkers of interest at p&lt;0.05.ResultsParticipants with DLB (n = 27;78.48±9.0years‐old;eleven APOE‐ε4 carriers) were paired with participants with AD (n = 27;81.00±5.8years‐old;twelve APOE‐ε4 carriers) and controls (n = 27;78.48±8.7years‐old;four APOE‐ε4 carriers); two thirds were women. CSF ACE‐1 activity was associated with CSF ACE‐1 levels (p&lt;0.0001) and with plasma ACE‐1 activity (p&lt;0.0001), no differences among the participants. Only in DLB, the ACE deletion allele was cumulatively associated with higher plasma ACE‐1 activity (p = 0.049). Use of ACE inhibitors did not affect CSF ACE‐1 levels. For APOE‐ε4 carriers with DLB, agitation was inversely associated with amyloid‐β38, CSF and plasma ACE‐1 activities. For APOE‐ε4 non‐carriers with DLB, appetite and eating abnormalities were associated with CSF ACE‐1 levels and activity, tau and tau/phospho‐tau, and inversely associated with amyloid‐β42/amyloid‐β38. CSF ACE‐1, tau, tau/phospho‐tau, and tau/amyloid‐β42 were associated with disinhibition for APOE‐ε4 carriers with AD, and with aberrant motor behavior for APOE‐ε4 non‐carriers with AD. For APOE‐ε4 carriers with AD, irritability was associated with CSF ACE‐1 and inversely associated with amyloid‐β42. All other behavioral associations with ACE‐1 were independent of measures of amyloidosis or tauopathy.ConclusionsBiofluid activity and CSF levels of ACE‐1 may be surrogates for CSF amyloid‐β levels and tauopathy unevenly associated with behavioral symptoms across dementia syndromes.

Disambiguating the macro‐scale anatomy of dysexecutive and behavioral degenerative diseases of the mind

AbstractBackgroundThere is a longstanding ambiguity regarding the clinical diagnosis of dementia syndromes predominantly targeting executive functions versus behavior/personality. This is due to a lack of knowledge about the macro‐scale anatomy underlying these symptomatologies, a partial overlap in clinical features, and the fact that a single underlying pathology can give rise to both phenotypes and vice‐versa.MethodWe included data from patients with genetic, biomarker, and/or autopsy evidence for fronto‐temporal lobar degeneration (FTLD) diagnosed with behavioral variant fronto‐temporal dementia (bvFTD, n = 30) and patients with biomarker and/or autopsy evidence for Alzheimer’s disease (AD) pathology diagnosed with either an initial and predominant dysexecutive (dAD, n = 52), behavioral (bvAD, n = 7), or amnestic (aAD, n = 28) syndrome. We assessed group‐wise differences in clinical/cognitive features and 18Fluorodeoxyglucose‐positron emission tomography (FDG‐PET) patterns. This was followed by a spectral covariance decomposition between FDG‐PET images to yield latent patterns of relative metabolism (“eigenbrains”). These eigenbrains were subsequently linked to clinical/cognitive data and meta‐analytic topics reflecting a wide range of mental abilities. We used a linear discriminant analysis (LDA) to perform eigenbrain‐based diagnostic predictions.ResultdAD and bvFTD patients were the youngest at symptom onset, followed by bvAD, then aAD. dAD patients had worse cognitive performance on nearly all cognitive domains compared to other groups. Hypometabolism was observed across associative cortices in dAD, temporo‐parietal areas in aAD, and fronto‐temporal areas in bvFTD and bvAD (Fig. 1). The spectral covariance decomposition yielded nine eigenbrains which explained 61% of the variance in patterns of FDG‐PET, and only the first three are presented (Fig. 2). These eigenbrains revealed that relative hypometabolism in association cortices, notably lateral parietal areas, associated with dysexecutive symptomatology and a lower likelihood of behavior/personality problems, whereas relative hypometabolism restricted to frontal and temporopolar areas showed opposite associations. The LDA yielded an accuracy of 82.1% in predicting diagnostic category (Fig. 3).ConclusionThis study suggests distinct macro‐scale underpinnings underlying predominant dysexecutive versus behavioral symptomatology in degenerative dementia phenotypes. This has implication for the implementation of clinical and research criteria for these dementia syndromes and highlights the importance of data‐driven techniques to inform the classification of degenerative diseases.

Differential performance of cerebrospinal fluid biomarker ratios and formulas to discriminate dementia with Lewy bodies from Alzheimer’s dementia and cognitively healthy people reflects high level of amyloidosis across dementia syndromes

AbstractBackgroundNeurodegeneration is a common hallmark of all dementia syndromes, whereas cerebrospinal fluid amyloid‐β may reflect amyloidosis both in Alzheimer’s dementia (AD) and in dementia with Lewy bodies (DLB). It is unknown if any biomarker profiles may help discriminate DLB from AD.MethodsConsecutive outpatients with probable DLB (fourth consensus report of the DLB Consortium) were paired with outpatients with late‐onset AD (National Institute on Aging – Alzheimer’s Association) by sex, Clinical Dementia Rating and Mini‐Mental State Examination scores, and with cognitively healthy controls by sex and age (±1 year). Genotyping of rs7412 &amp; rs429358 (APOE) was undertaken with TaqMan® Real‐Time PCR technology. Cerebrospinal fluid concentrations of amyloid‐β (Aβ42, Aβ40, Aβ38), α‐synuclein, t‐tau and p‐tau Thr181, were assessed by enzyme‐linked immunosorbent assays. The following ratios and restructured traditional regression formulas were compared among participants: Aβ42/Aβ40, Aβ42/Aβ38, t‐tau/p‐tau, t‐tau/Aβ42, p‐tau/Aβ42, α‐synuclein/Aβ42, t‐tau/α‐synuclein, (240+1.18Xt‐tau)/Aβ42, (3.694+0.0105Xt‐tau)Xp‐tau/Aβ42, (373+0.82Xt‐tau)/Aβ42, (152+8.25Xp‐tau)/Aβ42. In addition, all formulas were considered to correspond to an AD profile if &gt;1, while t‐tau/Aβ42&gt;0.5 and p‐tau/Aβ42&gt;0.08 were also measured, significance at p&lt;0.05.ResultsOverall, 27 participants with DLB (78.48±9.0 years‐old, CDR sum‐of‐boxes 10.96±3.8, eleven APOE‐ε4 carriers) were paired with 27 participants with AD (81.00±5.8 years‐old, CDR sum‐of‐boxes 10.44±3.9, twelve APOE‐ε4 carriers) and 27 controls (78.48±8.7 years‐old, CDR sum‐of‐boxes 0.30±0.8, four APOE‐ε4 carriers); two thirds were women. Only for APOE‐ε4 carriers, t‐tau/Aβ42 (p = 0.065) and t‐tau/α‐synuclein (p = 0.073) were marginally significantly higher in AD. Only for APOE‐ε4 non‐carriers, Aβ42/Aβ38 was higher (p = 0.009) and α‐synuclein/Aβ42 was lower (p = 0.043) in DLB. The t‐tau/Aβ42&gt;0.5 (p = 0.039) and p‐tau/Aβ42&gt;0.08 (p = 0.042) ratios were able to discriminate patients with AD from controls, but not from patients with DLB, regardless of APOE‐ε4 carrier status. All formulas were able to discriminate patients with AD from controls (p&lt;0.02), but only (152+8.25Xp‐tau)/Aβ42&gt;1 was able to discriminate patients with AD from patients with DLB (p = 0.025), regardless of APOE‐ε4 carrier status.ConclusionsAmyloidosis and neurodegeneration are modulated by APOE‐ε4 carrier status and may differentially affect the discriminative power of cerebrospinal fluid biomarker ratios for diagnosis of dementia syndromes. The best formula to discriminate patients with AD from patients with DLB and controls was (152+8.25Xp‐tau)/Aβ42&gt;1. (Supported by FAPESP grant #2015/10109‐5)