Diagnosis and management of dementia with Lewy bodies: Fourth consensus report of the DLB Consortium

Development and validation of a harmonized memory score for multicenter Alzheimer's disease and related dementia research

INTRODUCTION

List-learning tasks are important for characterizing memory in ADRD research, but the Uniform Data Set neuropsychological battery (UDS-NB) lacks a list-learning paradigm; thus, sites administer a range of tests. We developed a harmonized memory composite that incorporates UDS memory tests and multiple list-learning tasks.

METHODS

Item-banking confirmatory factor analysis was applied to develop a memory composite in a diagnostically heterogenous sample (n=5943) who completed the UDS-NB and one of five list-learning tasks. Construct validity was evaluated through associations with demographics, disease severity, cognitive tasks, brain volume, and plasma phosphorylated tau (p-tau181 and p-tau217). Test-retest reliability was assessed. Analyses were replicated in a racially/ethnically diverse cohort (n=1058).

RESULTS

Fit indices, loadings, distributions, and test-retest reliability were adequate. Expected associations with demographics and clinical measures within development and validation cohorts supported validity.

DISCUSSION

This composite enables researchers to incorporate multiple list-learning tasks with other UDS measures to create a single metric.

Evaluating the diagnostic performance of six plasma biomarkers for Alzheimer's disease and other neurodegenerative dementias in a large Chinese cohort

BACKGROUND

Ethnic variations and detection methods may lead to differences in diagnostic biomarkers of dementia, and few comparative studies have evaluated the six plasma biomarkers of Alzheimer's disease (AD) and other neurodegenerative dementias in the Chinese population.

METHODS

A cross-sectional cohort of 668 participants were enrolled, including 245 amnesic mild cognitive impairment (aMCI) or AD patients with Aβ positive pathology, 67 with frontotemporal dementia (FTD), 100 with progressive supranuclear palsy (PSP), 72 with dementia with Lewy bodies (DLB) and 184 healthy controls. Additionally, a longitudinal subset of 19 aMCI and 30 AD patients was followed for an average period of 1 year. Plasma biomarkers, including p-tau181, p-tau217, p-tau231, NfL, GFAP, and α-synuclein, were simultaneously measured using a novel single molecular array method. Aβ42 and p-tau181 levels in CSF, amyloid PET and structural MRI were measured.

RESULTS

Plasma p-tau217 and p-tau231 were most effective in diagnosing aMCI/AD (AUC = 0.95 and 0.93, respectively), while p-tau217, p-tau231 and p-tau181 presented the best differential diagnosis for AD from PSP, FTD and DLB respectively (AUC = 0.84, 0.81 and 0.83). α-synuclein was presented as the best biomarker for PSP variant and behavior variant FTD subtypes (AUC = 0.81 and 0.74, respectively). Among them, p-tau217, p-tau231, GFAP and a-synuclein were negatively correlated with CSF Aβ42/40, while p-tau217 and GFAP were positively correlated with CSF p-tau181. Besides, p-tau181, p-tau217, and GFAP were associated with temporal lobe volume, while p-tau231 and GFAP were associated with frontal lobe volume. Longitudinal analysis showed the higher p-tau181 could predict the cognitive decline progression.

CONCLUSIONS

This study validate the practicality of blood biomarkers in the Chinese Han population using a novel single molecule immune detection method. Through the clinical performance study for several biomarkers, we found the plasma p-tau217 was the most effective biomarker in AD diagnosis, and p-tau showed high accuracy for differential diagnosis of AD from other dementia, GFAP is associated with multiple aspects of AD pathology, and frontal and temporal lobe volume, and p-tau181 can reflect the dynamic cognitive decline of AD.

Altered Intra- and Inter-Network Resting-State Functional Connectivity is Associated with Neuropsychological Functioning and Clinical Symptoms in Patients with Isolated Rapid Eye Movement Sleep Behavior Disorder

BACKGROUND

Isolated rapid-eye movement (REM) sleep behavior disorder (iRBD) is characterized by abnormal behaviors in REM sleep and is considered as a prodromal symptom of alpha-synucleinopathies. Resting-state functional magnetic resonance imaging (rsfMRI) studies have unveiled altered functional connectivity (rsFC) in patients with iRBD. However, the associations between intra- and inter-network rsFC with clinical symptoms and neuropsychological functioning in iRBD remain unclear.

OBJECTIVE

To characterize intra- and inter-network rsFC in iRBD patients using a data-driven approach and to assess its associations with clinical features and cognitive functioning.

METHODS

Forty-two patients with iRBD and 45 healthy controls (HC) underwent rsfMRI and comprehensive neuropsychological testing. Resting-state networks were characterized using independent component analyses. Group differences in intra- and inter-network rsFC and their associations with clinical and neuropsychological data were studied. A threshold of corrected P < 0.05 was used in all the analyses.

RESULTS

iRBD patients displayed lower intra-network rsFC within basal ganglia, visual, sensorimotor, and cerebellar networks, relative to HC. Mean rsFC strength within the basal ganglia network positively correlated with processing speed and negatively with the non-motor symptoms in iRBD patients. Reduced inter-network rsFC between sensorimotor and visual medial networks was observed in iRBD patients, which was associated with global cognitive status.

CONCLUSIONS

iRBD is characterized by both reductions in intra-network rsFC in cortical and subcortical networks and inter-network dysconnectivity between sensorimotor and visual networks. Abnormalities in intra- and inter-network rsFC are associated with cognitive performance and non-motor symptoms, suggesting the utility of both rsFC measures as imaging markers in prodromal alpha-synucleinopathies. © 2025 The Author(s). Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Criminal Behavior in Early Onset Neurodegenerative Diseases

INTRODUCTION

Literature on criminal behavior preceding a neurodegenerative disease diagnosis is insufficient. Some studies suggest increased crime rates among patients with frontotemporal dementia (FTD).

METHODS

Patients with neurodegenerative diseases were gathered from Kuopio and Oulu University Hospitals and compared with nonselective general population data from Statistics Finland (N = 24,144). Clinical data were linked to the Finnish national register of police-reported crimes.

RESULTS

In total, 2424 participants with neurodegenerative diseases were included. Overall crime rates were notably higher among patients with FTD during the year before the diagnosis (9.4% for FTD, 6.3% for controls, p = 0.019). There was a significant drop in the criminal rates of FTD patients 3 years after the diagnosis (4.7% in the FTD, 12.3% in controls, p < 0.001).

DISCUSSION

Criminal behavior is overrepresented in patients with FTD before the diagnosis. Criminal behavior manifesting in previously law-abiding individuals in late adulthood should be considered a potential early symptom of a neurodegenerative disease.

REM sleep and neurodegeneration

Several brainstem, subcortical and cortical areas are involved in the generation of rapid eye movement (REM) sleep. The alteration of these structures as a result of a neurodegenerative process may therefore lead to REM sleep anomalies. REM sleep behaviour disorder is associated with nightmares, dream-enacting behaviours and increased electromyographic activity in REM sleep. Its isolated form is a harbinger of synucleinopathies such as Parkinson's disease or dementia with Lewy bodies, and neuroprotective interventions are advocated. This link might also be present in patients taking antidepressants, with post-traumatic stress disorder, or with a history of repeated traumatic head injury. REM sleep likely contributes to normal memory processes. Its alteration has also been proposed to be part of the neuropathological changes occurring in Alzheimer's disease.

Identification of Common Brain Protein and Genetic Loci Between Parkinson's Disease and Lewy Body Dementia

BACKGROUND

Parkinson's disease (PD) and Lewy body dementia (LBD) have many common features, including clinical manifestations, neurochemistry, and pathology, but little is known about their shared brain proteins and genetic factors.

METHODS

To identify susceptibility-related brain proteins that are shared between PD and LBD patients, proteome-wide association studies (PWASs) were conducted by integrating human brain protein quantitative trait loci (pQTLs) with large-scale genome-wide association studies (GWASs) of both diseases. Subsequently, pleiotropy-informed conditional false discovery rate (pleioFDR) analysis was performed to identify common risk genetic loci between PD and LBD. Finally, the downregulation of these risk genes in different disease states was validated by differential gene expression analysis.

RESULTS

PWASs identified 12 PD risk proteins and nine LBD risk proteins, among which TMEM175 (zPD = -7.25, PPD = 4.12E-13; zLBD = -6.02, PLBD = 1.75E-09) and DOC2A (zPD = -4.13, PPD = 3.71E-05; zLBD = -3.91, PLBD = 9.08E-05) were shared. PleioFDR analysis revealed that five genetic risk loci mapped to eight genes associated with PD and LBD, including the proteome-wide significant risk gene TMEM175 (ConjFDR = 5.74E-03). Differential expression analysis verified that TMEM175 was significantly downregulated in the midbrains of PD patients (p = 1.19E-02), and further exploration revealed that TMEM175 was also dramatically downregulated in the substantia nigra of PD patients (p = 1.16E-02) and incidental Lewy body disease patients (p = 7.52E-03). Moreover, TMEM175 was significantly downregulated in induced pluripotent stem cell-derived dopaminergic neurons from PD patients (p = 4.60E-02).

CONCLUSION

Dysregulation of TMEM175 may confer PD and LBD risk and may be partly responsible for their comorbidity. Our results revealed the common genetic risk factors between PD and LBD, which elucidated the shared genetic basis of these diseases.

Examining the association between sleep apnea and total hippocampal volumes in cognitive impairment

INTRODUCTION

The prevalence of dementia is rising due to an aging population. Given the known risks of obstructive sleep apnea (OSA) on cerebrovascular health, we hypothesized that markers of OSA would correlate with reduced hippocampal volumes in individuals with cognitive impairment due to neurodegenerative, vascular, or mixed (NVM) etiologies.

METHODS

Data from 166 patients were retrospectively analyzed. Participants underwent polysomnography or home sleep apnea tests, alongside structural brain magnetic resonance imaging (MRI). They were categorized into cognitive impairment due to NVM etiology or subjective cognitive complaints. Multiple linear regression models examined correlations between sleep variables and hippocampal volume.

RESULTS

The presence of OSA, time under 90% oxygen saturation, and mean SpO2 were significantly associated with reduced hippocampal volumes in the NVM group, but not the subjective cognitive complaints.

DISCUSSION

These findings suggest that individuals with cognitive impairment due to NVM etiology experience underlying neurodegenerative processes, which increase susceptibility to the adverse effects of OSA.

HIGHLIGHTS

Hypoxic burden, rather than AHI, was associated with hippocampal volume loss. The presence of OSA, T90%, and mean SpO2 were linked with reduced hippocampal volume. Neurodegenerative and vascular processes may raise susceptibility to OSA harms.

Aberrant accumulation of phosphorylated BRCA1 in brainstem-type and cortical-type Lewy bodies in Lewy body disease

BRCA1 plays important roles in several biological events during the DNA damage response (DDR). We aimed to determine whether cytoplasmic accumulation of BRCA1 or its phosphorylated form, pBRCA1, is specific to cytoplasmic inclusions in tauopathies, or if it also occurs in α-synuclein-positive inclusions in Lewy body disease (LBD). Using brain tissue from pure LBD, LBD with Alzheimer disease (AD) co-pathology (LBD-AD), and control cases, the immunohistochemical distributions of BRCA1, pBRCA1, its binding partner BARD1, and 53BP1 were examined. The results showed that pBRCA1 (Ser1423) and BARD1 accumulated in brainstem-type Lewy bodies (LBs), whereas only pBRCA1 (Ser1423) was present in cortical-type LBs. There was no significant difference in the frequency of pBRCA1 (Ser1423)-positive LBs between the pure LBD and LBD-AD cases. pBRCA1 (Ser1423) was minimally detected in neuronal nuclei in controls and was absent in neuronal nuclei in LBD cases. In control and LBD cases, 53BP1-immunoreactive deposits were present in the neuronal nuclei. Thus, DDR dysfunction due to cytoplasmic sequestration of pBRCA1 (Ser1423) may play a role in LBD pathogenesis. Additionally, the selective accumulation of BARD1 in brainstem-type LBs, but not cortical-type LBs, points to distinct mechanisms in the formation of these inclusion types, offering further insights into LBD pathology.

Brás Cubas, Quincas Borba, and Rubião: portraits of neuropsychiatry in the novels of Machado de Assis

The intersection of literature and neuroscience provides a fascinating way to explore human behavior through fictional narratives. Brazilian literature, particularly the work of Machado de Assis, excels in portraying characters with neuropsychiatric conditions. This work aims to establish connections between the fictional representations of human behavior in Machado's classic works and neurological conditions described by contemporary neuroscience. In The Posthumous Memoirs of Brás Cubas and Quincas Borba, Machado's characters exhibit behaviors that align with modern neurological diagnoses. For example, Brás Cubas experiences episodes resembling delirium, characterized by mental confusion and altered cognition, while Quincas Borba shows traits of attention deficit hyperactivity disorder (ADHD) and bipolar disorder. Rubião, the protagonist of Quincas Borba, meets certain criteria for dementia, displaying visual hallucinations and cognitive fluctuations. By analyzing Machado's characters through a neuropsychiatric lens, we can appreciate his remarkable ability to depict complex mental conditions, many of which were not fully understood by medicine at the time.

Central Involvement in Pure Autonomic Failure: Insights from Neuromelanin-Sensitive Magnetic Resonance Imaging and 18F-Fluorodopa-Positron Emission Tomography

BACKGROUND

Central synucleinopathies, including Parkinson's disease (PD), dementia with Lewy bodies (DLB), and multiple system atrophy (MSA), involve alpha-synuclein accumulation and dopaminergic cell loss in the substantia nigra (SN) and locus coeruleus (LC). Pure autonomic failure (PAF), a peripheral synucleinopathy, often precedes central synucleinopathies.

OBJECTIVES

To assess early brain involvement in PAF using neuromelanin-sensitive magnetic resonance imaging (NM-MRI) and fluorodopa-positron emission tomography (FDOPA-PET), and to determine whether PAF patients with a high likelihood ratio (LR) for conversion to a central synucleinopathy exhibit reduced NM-MRI contrast in the LC and SN compared with controls and low-LR patients.

METHODS

Participants with PAF (n = 23) were categorized as high-LR (n = 13) or low-LR (n = 10) for conversion to central synucleinopathy. Additional participants included PD (n = 22), DLB (n = 8), and age- and sex-matched healthy controls (n = 23). NM-MRI at 3 T was used to quantify contrast ratios in the LC and SN, while FDOPA-PET measured presynaptic dopamine synthesis. Linear regression analyses, adjusted for age and sex, were used to compare NM-MRI contrast across groups.

RESULTS

High-LR PAF patients showed reduced contrast in the LC and SN compared with controls and low-LR PAF patients, with values similar to PD and DLB. The NM-MRI contrast in the SN correlated with dopamine uptake in the striatum. Longitudinal imaging in PAF patients (n = 6) demonstrated reduced NM-MRI and PET values in individuals who developed central synucleinopathies.

CONCLUSIONS

NM-MRI and FDOPA-PET may serve as potential biomarkers for early brain involvement and predicting progression to central synucleinopathies in PAF and could help identify patients for early intervention. © 2025 The Author(s). Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

A new paradigm for neurodegenerative diseases classification: A clinical perspective

A vast progress has been made in the understanding of neurodegenerative diseases during the past few years. However, clinical diagnostic accuracy continues to be very low, despite the introduction of various diagnostic tools and repeated revisions of diagnostic criteria. For instance, patients with Alzheimer's disease (AD) may present with symptoms that overlap with other neurodegenerative conditions like dementia with Lewy bodies (DLB), making accurate diagnosis challenging. This diagnostic uncertainty can lead to delayed or incorrect treatment, significantly impacting patients' quality of life and prognosis. Thus, the definite diagnosis still relies on post-mortem pathological findings, placing a significant burden on both clinicians and researchers. As a growing body of evidence indicates, co-pathology seems to be the rule among neurodegenerative diseases. Additionally, a single pathological diagnosis, such as AD, can manifest in various clinical presentations, ranging from predominantly cognitive impairment to significant motor symptoms. Each of these presentations currently requires its own set of complicated diagnostic criteria. Perhaps, the time has come for a much-needed radical revision of existing clinical diagnostic criteria. Inclusion of patients do not neatly fit into existing diagnostic categories for neurodegenerative diseases, in future large-scale, longitudinal studies and/or clinical trials, and systematic assessment of their clinical features and disease progression using machine learning could generate valuable data on patients with mixed pathologies and improve our understanding of how to effectively treat these complex cases.

Disproportionately Enlarged Subarachnoid-Space Hydrocephalus on MRI in Pathologically Confirmed Progressive Supranuclear Palsy

Background and Objective

Several studies have shown that idiopathic normal-pressure hydrocephalus (iNPH) can mimic other neurodegenerative disorders, particularly progressive supranuclear palsy (PSP). In this study, we investigated iNPH clinical and neuroimaging features in patients with autopsy-confirmed PSP or Lewy body disease (LBD) by assessing the normal pressure hydrocephalus (NPH) triad of symptoms and imaging features of disproportionately enlarged subarachnoid-space hydrocephalus (DESH) and Evans index (EI) on antemortem MRI scans.

Methods

Among our study participants (N = 190), the mean (SD) age was 76.8 (9.2) years and 134 (70.5%) were male. The patients had been followed at Mayo Clinic and had autopsy diagnosis of either PSP or LBD. Patients were excluded if they had Alzheimer disease or a history of a disorder that could cause hydrocephalus, such as chronic meningitis or neoplasia. The study included 101 patients with PSP and 89 with LBD. The frequency of DESH and a high EI on brain MRI were analyzed in PSP and LBD with logistic regression analyses, adjusting for age, sex, and brain weight. The NPH triad of symptoms was assessed relative to imaging findings.

Results

We found that DESH and high EI were similar between PSP and LBD. The mean age at death (PSP: 74.0 [8.2]; LBD: 80.0 [9.2]) and brain weight (PSP: 1,190 [123]; LBD: 1,300 [150]) were greater in LBD compared with PSP (p < 0.001 for each). The frequency of DESH was greater in LBD than PSP (13% vs 3%, p = 0.004), while a high EI was similar in PSP and LBD (36% vs 32%, p = 0.500). The adjusted odds ratios for DESH and high EI were similar between the 2 groups (DESH: adjusted ORs 0.3, 95% CI 0.06-1.25, p = 0.119; high EI: adjusted ORs 1.8, 95% CI 0.86-4.06, p = 0.120).

Discussion

These findings suggest that DESH and high EI, often considered biomarkers for iNPH, may lack specificity and may be found in a subset of patients with PSP or LBD leading to unnecessary neurosurgery for iNPH.

Validation of the Brief Assessment of Impaired Cognition and Brief Assessment of Impaired Cognition Questionnaire in a multicultural memory clinic sample across six European countries

BackgroundWith the changing demographic landscape in most countries worldwide, accurate and brief culture-sensitive case-finding instruments are needed to identify patients with possible cognitive disorders.ObjectiveTo investigate the discriminative validity of the Brief Assessment of Impaired Cognition (BASIC) and BASIC Questionnaire (BASIC-Q) in a multicultural memory clinic sample across six European countries.MethodsThe study was a European cross-sectional multi-center study. Receiver operating characteristic curve analysis was used to examine discriminative validity of BASIC and BASIC-Q in identifying cognitive impairment (mild cognitive impairment (MCI) or dementia) as compared to specialist diagnosis. Regression analysis was used to assess the influence of sociodemographic variables and assessment in a second language on scores.ResultsThe study included a total of 479 participants of which 169 (36%) had immigrant background. BASIC and BASIC-Q had high diagnostic accuracy for cognitive impairment (MCI or dementia) with areas under the curve (AUC) of 0.93 and 0.92, respectively. Age had a significant, but small effect on BASIC, while both BASIC and BASIC-Q were unaffected by sex, education, immigrant status, and assessment in a second language. Among patients with affective/anxiety disorder, 80% scored below cutoff for cognitive impairment on BASIC and 94% on BASIC-Q. However, applying an Objective Performance vs. Subjective Complaints ratio to differentiate between patients with cognitive impairment and affective/anxiety disorder resulted in high overall classification accuracies, with AUC values of 0.80 and 0.74, respectively.ConclusionsThe present study suggests that BASIC and BASIC-Q are valid brief case-finding instruments for cognitive impairment in a multicultural setting.

Platelets mirror changes in the frontal lobe antioxidant system in Alzheimer's disease

INTRODUCTION

Blood biomarkers reflecting Alzheimer's disease (AD) pathophysiology can improve diagnosis and treatment.

METHODS

We applied top-down proteomics to compare frontal lobe from 17 AD cases and 11 controls to blood platelets from a second independent study group of 124 AD patients, 61 with mild cognitive impairment (MCI), and 168 controls. Findings were immunologically validated.

RESULTS

Sixty AD-associated proteoforms were identified in frontal lobe, with 26 identically represented in platelets. Validation in platelet samples confirmed elevated glutathione S-transferase omega 1 (GSTO1) levels linked to single nucleotide polymorphism (SNP) rs4925 and increased superoxide dismutase 1 (SOD1) levels in AD. Bioinformatics revealed copper chaperone for superoxide dismutase (CCS) and glutathione peroxidase 1 (GPX1) as integral partners of these antioxidant enzymes. Both were detected to be reduced in frontal lobes and platelets in AD. SOD1 and CCS are already changed in MCI.

DISCUSSION

These four novel blood biomarkers, integrated with traditional AD biomarkers, may facilitate patient risk assessment and treatment, with SOD1 and CCS alterations in MCI offering early diagnostic potential.

HIGHLIGHTS

Platelets mirror several Alzheimer's disease (AD)-dependent neuronal changes, valuable for blood tests. As a start, 60 AD-associated frontal lobe proteins were identified by top-down proteomics. Fifty percent of these 60 AD-affected brain proteins are represented identically in platelets. Among these, glutathione S-transferase omega 1 (GSTO1), superoxide dismutase 1 (SOD1), copper chaperone for superoxide dismutase (CCS), and glutathione peroxidase 1 (GPX1) are identically AD related in brain and platelets. SOD1 and its crucial activating partner CCS are altered in the platelets of patients with mild cognitive impairment.

"Chocolate Chip Sign" on Susceptibility-Weighted Imaging: A Novel Neuroimaging Biomarker for HTRA1-Related Cerebral Small Vessel Disease

Background and Objectives

HTRA1-related cerebral small vessel disease (HRSVD) is a rare hereditary form of cerebral small vessel disease (CSVD) caused by HTRA1 pathogenic variants. Diagnosing HRSVD without genetic testing is challenging because of the lack of distinctive imaging features and clinical symptoms, and even family history can be unclear in some cases with HRSVD. This study investigates whether susceptibility-weighted imaging (SWI) can identify useful diagnostic findings for HRSVD.

Methods

This retrospective study included 8 patients with HRSVD, 12 with cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), and 14 with sporadic CSVD (sCSVD). Two neurologists blinded to clinical data counted the number of hypointense dots around the midbrain on SWI. Receiver operating characteristic curve analysis evaluated the optimal threshold of the number that can distinguish HRSVD and CADASIL or sCSVD. In addition, histopathologic analysis including measurement of leptomeningeal vessel diameter and type III collagen deposition was performed on autopsied brains from 3 cases each of HRSVD, CADASIL, and sCSVD and control participants.

Results

Patients with HRSVD exhibited a significantly higher number of hypointense dots around the midbrain on SWI compared with CADASIL and sCSVD groups. A threshold of 5 or more dots, termed the "Chocolate Chip Sign," well distinguished HRSVD from CADASIL and sCSVD (area under the curve: 0.817, 95% confidence interval: 0.624-1.00). Three-dimensional SWI reconstruction and 7T MRI confirmed these dots as dilated extraparenchymal vessels. Histopathologic analysis revealed pronounced dilation of leptomeningeal veins with type III collagen accumulation specifically, in HRSVD brains.

Discussion

The Chocolate Chip Sign on SWI represents a novel and promising neuroimaging biomarker for HRSVD. This finding holds significant potential for facilitating early diagnosis, prompting timely genetic testing, and appropriate family screening for this rare genetic disorder.

Sex differences in clinical phenotypes of behavioral variant frontotemporal dementia

INTRODUCTION

Higher male prevalence in sporadic behavioral variant frontotemporal dementia (bvFTD) has been reported. We hypothesized differences in phenotypes between genetic and sporadic bvFTD females resulting in underdiagnosis of sporadic bvFTD females.

METHODS

We included genetic and sporadic bvFTD patients from two multicenter cohorts. We compared behavioral and cognitive symptoms, and gray matter volumes, between genetic and sporadic cases in each sex.

RESULTS

Females with sporadic bvFTD showed worse compulsive behavior (p = 0.026) and language impairments (p = 0.024) compared to females with genetic bvFTD (n = 152). Genetic bvFTD females had smaller gray matter volumes than sporadic bvFTD females, particularly in the parietal lobe.

DISCUSSION

Females with sporadic bvFTD exhibit a distinct clinical phenotype compared to females with genetic bvFTD. This difference may explain the discrepancy in prevalence between genetic and sporadic cases, as some females without genetic mutations may be misdiagnosed due to atypical bvFTD symptom presentation.

HIGHLIGHTS

Sex ratio is equal in genetic behavioral variant of frontotemporal dementia (bvFTD), whereas more males are present in sporadic bvFTD. Distinct neuropsychiatric phenotypes exist between sporadic and genetic bvFTD in females. Phenotype might explain the sex ratio difference between sporadic and genetic cases.

Postural Sway Characteristics Distinguish Types of Dementia

OBJECTIVES

The increasing number of patients with dementia necessitates the development of rapid and convenient tools to assist with dementia diagnosis. We previously demonstrated the difference in the postural control characteristics during static standing among Alzheimer disease (AD), dementia with Lewy bodies (DLB), and vascular dementia (VaD). In this study, we evaluated the classification accuracy of the postural sway test to assess its capacity to distinguish between types of dementia.

DESIGN

A cross-sectional study.

SETTING AND PARTICIPANTS

Memory clinic outpatients aged 65-85 years who were clinically diagnosed with AD, DLB, VaD, and cognitively normal (CN) outpatients.

METHODS

Static upright standing measurements were conducted under open- and closed-eye conditions to calculate 40 parameters. After variable selection based on statistical significance, 3 dementia classification models (AD vs DLB, AD vs VaD, and DLB vs VaD) based on postural control parameters were created. Bias-corrected accuracy measures using bootstraps were used for assessing the classification performances.

RESULTS

The data of 1734 participants (1158 with AD, 105 with DLB, 46 with VaD, and 425 with CN) were analyzed. The area under the curves of receiver operating characteristic curves for AD vs DLB, AD vs VaD, and DLB vs VaD were 0.647 (0.646-0.649), 0.763 (0.761-0.765), and 0.659 (0.656-0.662), respectively.

CONCLUSIONS AND IMPLICATIONS

Postural control characteristics differentiated between dementia types with reasonable to good accuracy, especially in the comparison between AD and VaD. Postural control testing may become a valuable assistive tool for dementia diagnosis in the future.

Associations between neuropsychiatric symptoms and pathology in clinicopathologically defined Alzheimer's disease, Alzheimer's disease with Lewy bodies, and dementia with Lewy bodies

BackgroundNeuropsychiatric symptoms (NPS) are frequent in Alzheimer's disease (AD) dementia, but a higher NPS burden is found in dementia with Lewy bodies (DLB). Lewy body (LB) pathology frequently co-occurs with AD pathology and may not meet neuropathological criteria for DLB (ADLB). NPS trajectories over disease course in these subgroups is not well understood.ObjectiveWe investigated changes in NPS severity over time, at two time points, comparing clinicopathologically defined cohorts of AD (without LB), ADLB, DLB, and controls.MethodsCases with two available Neuropsychiatric Inventory-Questionnaire (NPIQ), at the time of enrollment and within 2.5 years of death, were selected from the Arizona Study of Aging and Neurodegenerative Disorders. Differences and rate of change in NPIQ scores were compared between AD (n = 75), ADLB (n = 48) DLB (n = 65), and controls (n = 32) with covariates for age, sex, and cognition.ResultsFirst NPIQ scores were highest in ADLB when compared to AD (p = 0.04) and controls (p = 0.01) but not different from DLB. A significant increase in NPS severity was observed in DLB and AD (p < 0.001) over a mean follow up time of 4.9 ± 3.0 years, and the rate of change was significantly greater in DLB when compared to other groups. Final NPIQ scores were highest in DLB when compared to AD (p = 0.03) but not ADLB, and in DLB, ADLB, and AD than controls (all p < 0.001).ConclusionsEarly NPS burden as well as NPS severity progression rate, independently of cognitive status, might be useful clinical metrics and may help predict underlying pathological diagnoses.

Blood biomarker profiles in young-onset neurocognitive disorders: A cohort study

INTRODUCTION

Young-onset neurocognitive symptoms result from a heterogeneous group of neurological and psychiatric disorders which present a diagnostic challenge. To identify such factors, we analysed the Biomarkers in Younger-Onset Neurocognitive Disorders cohort, a study of individuals <65 years old presenting with neurocognitive symptoms for a diagnosis and who have undergone cognitive and biomarker analyses.

METHODS

Sixty-five participants (median age at assessment of 56 years, 45% female) were recruited during their index presentation to the Royal Melbourne Hospital Neuropsychiatry Centre, a tertiary specialist service in Melbourne, Australia, and categorized as either early-onset Alzheimer's disease (n = 18), non-Alzheimer's disease neurodegeneration (n = 23) or primary psychiatric disorders (n = 24). Levels of neurofilament light chain, glial fibrillary acidic protein and phosphorylated-tau 181, apolipoprotein E genotype and late-onset Alzheimer's disease polygenic risk scores were determined. Information-theoretic model selection identified discriminatory factors.

RESULTS

Neurofilament light chain, glial fibrillary acidic protein and phosphorylated-tau 181 levels were elevated in early-onset Alzheimer's disease compared with other diagnostic categories. A multi-omic model selection identified that a combination of cognitive and blood biomarkers, but not the polygenic risk score, discriminated between early-onset Alzheimer's disease and primary psychiatric disorders (area under the curve ⩾ 0.975, 95% confidence interval: 0.825-1.000). Phosphorylated-tau 181 alone significantly discriminated between early-onset Alzheimer's disease and non-Alzheimer's disease neurodegeneration causes (area under the curve = 0.950, 95% confidence interval: 0.877-1.00).

DISCUSSION

Discriminating between early-onset Alzheimer's disease, non-Alzheimer's disease neurodegeneration and primary psychiatric disorders causes of young-onset neurocognitive symptoms is possible by combining cognitive profiles with blood biomarkers. These results support utilizing blood biomarkers for the work-up of young-onset neurocognitive symptoms and highlight the need for the development of a young-onset Alzheimer's disease-specific polygenic risk score.

High Agreement Across Laboratories Between Different Alpha-Synuclein Seed Amplification Protocols

BACKGROUND

Seed amplification assays (SAA) detect alpha-synuclein (aSYN) pathology in patient biomatrices such as cerebrospinal fluid (CSF)-potentially even before clinical manifestations. As CSF-based SAA are approaching broader use in clinical trials and research, ensuring that different laboratories obtain the same results becomes increasingly important.

METHODS

In this cross-laboratory, cross-aSYN-recombinant substrate and cross-protocol round-robin test, we compared SAA results from a common set of 38 CSF samples measured independently in four research laboratories of the German Center for Neurodegenerative diseases. Three laboratories (A-C) used an assay protocol adapted from Parchi's group at ISNB (Bologna, Italy); laboratory D used an assay protocol adapted from Amprion Inc. Two different manufacturers of aSYN protein were used as substrates for the SAA reaction.

RESULTS

Qualitative results were identical in at least three of the four laboratories for 37 out of 38 samples (20 positive, 17 negative). Fleiss Kappa for all four laboratories was 0.751 (z = 12, p < 0.001). For each laboratory, agreement with laboratory A was > 92%. For the number of positive replicates, Fleiss Kappa was 0.45 for a score of zero positive replicates and 0.42 for a score of four positive replicates.

CONCLUSIONS

The qualitative SAA results showed a high level of agreement across research laboratories, aSYN monomers, and assay protocols. Small differences between laboratories were systematic, consistent with the notion that SAA reports biologically relevant properties. These results also underline that round-robin tests can be helpful in assessing and ensuring SAA quality across laboratories.

The Many Faces of REM Sleep Behavior Disorder. Providing Evidence for a New Lexicon

BACKGROUND

People with idiopathic/isolated REM sleep behavior disorder (iRBD) are highly heterogeneous, showing mild motor, cognitive, and dysautonomia symptoms. The aim of this study is to unveil the clinical heterogeneity of iRBD with a specific reference to overlapping features with prodromal Parkinson's disease (pPD) and prodromal dementia with Lewy bodies (pDLB) labels.

METHODS

People with a polysomnography-confirmed diagnosis of iRBD were enrolled and followed over time. At baseline, pPD and pDLB criteria were assessed.

RESULTS

Among the 285 iRBD people (68.2 ± 7.6 years, 81% males), due to additional signs or symptoms, 49.8% fulfilled pPD criteria only, 5.6% pDLB criteria only, and 14.4% subjects fulfilled both pPD and pDLB criteria. Conversely, about one third of iRBD people (30.2%) did not meet either pPD or pDLB criteria. At follow-up (40.6 ± 43.6 months), 28.8% subjects phenoconverted, developing PD (56.1%), DLB (39%), or multiple system atrophy (4.9%). Subjects with iRBD fulfilling either pPD or pDLB criteria, or both, have an increased risk of phenoconversion (adjusted hazard ratio, aHR 2.34, 95% confidence interval, CI 1.24-4.41). On the opposite, subjects not fulfilling prodromal criteria have a significantly reduced short-term phenoconversion likelihood (aHR 0.43, 95% CI 0.23-0.81). Notably, pPD and pDLB criteria did not predict PD and DLB diagnoses, respectively.

CONCLUSIONS

People with iRBD are highly heterogeneous, and the presence of other concomitant signs and symptoms is frequent, leading to faster phenoconversion. Thus, the terms idiopathic and isolated may be poorly appropriate and possibly even confounding. These results pave the way to a more appropriate new lexicon for people with RBD.

Validation of the neuropathological criteria of the fourth Consortium on dementia with Lewy Bodies in autopsy cases from psychiatric hospitals

AIM

The pathological criteria from the fourth Consortium on Dementia With Lewy bodies (DLB) in psychiatric cohorts has not been validated. Also, the pathological differences in prodromal DLB subtypes remain unclear. This study aimed to elucidate the clinicopathological features of patients with DLB in psychiatric hospitals.

METHODS

Of 165 autopsied cases, patients who developed psychiatric symptoms at 50 years or older were investigated based on the current criteria of DLB. Clinicopathological findings were compared among prodromal DLB subtypes.

RESULTS

Sixteen of 30 cases with DLB pathology had no parkinsonism, which represented diverse nigral neurodegeneration. Regarding the scheme to estimate the likelihood of DLB syndrome, the prevalence of core clinical features excluding rapid eye movement sleep behavior disorder and probable DLB diagnosis were significantly higher in the high-likelihood group than in the low-likelihood group. Regarding the prodromal DLB subtypes, mild cognitive impairment (MCI) onset was identified in 60%, psychiatric onset in 20%, delirium onset in 10%, and motor onset in 10% of cases, and the proportion of psychiatric onset or delirium onset was significantly higher compared with those without DLB pathology. Coexistence of MCI and psychiatric symptoms was observed in 41.6% of the MCI-onset cases. Patients with psychiatric-onset cases were significantly younger at the onset, with a longer disease duration than those with MCI-onset cases. No differences were observed in other clinicopathological variables among the subtypes.

CONCLUSION

The fourth Consortium pathological criteria for DLB were applicable in a psychiatric cohort. MCI-onset cases in conjunction with core clinical features is the main prodromal DLB subtype, and four cases exhibited isolated psychiatric symptoms for long-term duration.

Frequency and Longitudinal Course of Autonomic Reflex Testing Abnormalities in Isolated REM Sleep Behavior Disorder

STUDY OBJECTIVES

Autonomic dysfunction is common across the α-synucleinopathies including isolated RBD (iRBD), however the presence, severity and distribution of autonomic dysfunction as a risk factor for phenoconversion in iRBD remains unclear. We aimed to characterize autonomic reflex testing (ART) abnormalities in a cohort of participants with iRBD and assess them as phenoconversion biomarkers.

METHODS

We performed ART on 45 individuals with iRBD and evaluated the ability of ART components (sympathetic cholinergic, cardiovagal, sympathetic adrenergic) to predict phenoconversion using univariate and multivariate models combined with measures of olfaction, cognition, motor function, and skin biopsy assessment of dermal synuclein.

RESULTS

Forty-one individuals with iRBD were enrolled (age 66.7 ± 7.4 yrs, 27% female), and followed annually for an average of 2.9 ± 2.4 yrs, with four participants lost to follow-up. Eight participants with iRBD phenoconverted during their follow-up period (3 Parkinson's disease, 4 dementia with Lewy bodies and 1 multiple system atrophy), yielding a phenoconversion rate of 6.6% per year. Eighty-seven percent of iRBD participants had an abnormal baseline ART, and 100% had an abnormal follow-up ART. A combination of MDS-UPDRS III score and cardiovagal dysfunction (abnormal HRVdb) best predicted phenoconversion (AUC = 0.77), especially when combined with iRBD disease duration (AUC = 0.89).

CONCLUSIONS

ANS dysfunction was common and spanned all domains of autonomic function. Cardiovagal function was the most common domain affected and most predictive of phenoconversion, especially if combined with motor examination and disease duration. Longitudinal studies with larger sample sizes are needed to confirm these findings.

Plasma Biomarkers and Disease Prognosis in Mild Cognitive Impairment with Lewy Bodies

BACKGROUND

Little is known about the prognostic value of plasma biomarkers in mild cognitive impairment with Lewy bodies (MCI-LB).

OBJECTIVES

To investigate the association of four plasma biomarkers with disease progression in MCI.

METHODS

Plasma amyloid-beta (Aβ)42/40, glial fibrillary acidic protein (GFAP), neurofilament light (NfL), and phosphorylated tau 181 (pTau181) were measured at baseline in a longitudinal MCI cohort (n = 131).

RESULTS

Baseline plasma NfL was associated with increased risk of dementia/death in the entire cohort. In MCI-LB, baseline plasma NfL, GFAP, and pTau181 were associated with increased risk of dementia/death and increased cognitive decline measured by the Addenbrooke's Cognitive Examination-Revised.

CONCLUSIONS

pTau181, GFAP, and NfL are associated with more rapid disease progression in MCI-LB and, with further validation, could be useful to support prognosis and stratification for clinical practice and treatment trials. Further work, including clinicopathological studies, is needed to understand the biological correlates of these markers in MCI-LB. © 2025 The Author(s). Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Diagnostic performance of plasma p-tau217 in a memory clinic cohort using the Lumipulse automated platform

BACKGROUND

Plasma biomarkers for Alzheimer's disease (AD) are a promising tool for accessible and accurate biological diagnostics. However, data in clinical practice are needed to better understand their diagnostic and prognostic ability in memory unit patients.

METHODS

We analyzed plasma phosphorylated tau at threonine 217 (p-tau217) and neuroflament light chain (NfL) levels and AD cerebrospinal fluid (CSF) biomarkers in a group of 493 subjects using the Lumipulse G600II platform. The sample includes 340 patients from our memory unit (142 dementia, 186 mild cognitive impairment, and 12 with subjective complaints) and 153 cognitively unimpaired volunteers. We have correlated plasma and CSF biomarkers; we have analyzed plasma biomarker levels as a function of clinical diagnosis, cognitive status and amyloid status. We have also studied the ability of p-tau217 to discriminate between amyloid-positive and -negative subjects according to CSF using receiver operating characteristic curves.

RESULTS

Plasma p-tau217 correlated significantly with CSF Aβ42/Aβ40 (Rho = -0.75; p-value < 0.001), p-tau181 (r = 0.66; p-value < 0.001), and t-tau (r = 0.59; p-value < 0.001). Plasma NfL correlated with CSF NfL (r = 0.48; p-value < 0.001). By clinical diagnosis, plasma p-tau217 levels showed to be higher in AD patients than in healthy controls (difference = 0.63 pg/ml; p-value < 0.001), FTD (difference = 0.60 pg/ml; p-value < 0.001), and nondegenerative dementias (difference = 0.61 pg/ml; p-value < 0.001). Plasma p-tau217 showed an area under the curve of 0.95 to discriminate between A + and A- subjects (95%CI 0.93-0.97).

CONCLUSION

Plasma p-tau217 shows excellent results for detecting amyloid pathology at brain level in a clinical setting with an AUC of 0.95. It is a highly specific marker of AD and increases progressively along the disease continuum. Using plasma p-tau217 as an initial diagnostic tool with cut-offs at sensitivities and specificities of 95 or 97.5% could save between 57.4-84.8% of LP/PETs with diagnostic accuracies of 95-97%. Plasma NfL increases progressively at different cognitive stages.

Alpha-Synuclein Pathophysiology in Neurodegenerative Disorders: A Review Focusing on Molecular Mechanisms and Treatment Advances in Parkinson's Disease

Worldwide aging has contributed to the growth of prevalence of neurodegenerative diseases (NDDs), including Parkinson's disease among the elderlies. The advanced destruction of dopaminergic neurons in the substantia nigra, due to many accelerator factors in the brain is the main mechanism of Parkinson's disease. The pathological aggregated alpha-synuclein (α-syn), a protein implicated in multiple neurodegenerative disorders, is one of the critical factors in this neurodegenerative disease and other similar disorders. The misfolding and aggregation of α-syn may interrupt critical processes, including functions of synaptic vesicles and can lead to neuronal death. This protein is encoded by Alpha-Synuclein Gene (SNCA) and mutation in this gene can lead to dysfunctions of the protein structure. Since, therapeutic policies that aim α-syn are promising approaches. Advances in immunotherapies, molecular chaperones, gene therapy targeting SNCA, and DNA aptamers are some examples of this strategy. This review aims to comprehensively assess the current knowledge and evidence on α-syn pathology, genetic determinants, and novel therapeutic methods in Parkinson,'s disease and other synucleinopathies. Continued investigation to discover interventions in this system could result in finding of effective and safe treatments for NDDs.

A bibliometric analysis of 100 most-cited articles on behavioural and psychological symptoms of dementia (BPSD)

BACKGROUND

BPSD are a heterogeneous neuropsychiatric symptoms that are highly prevalent in persons with dementia (PwD). Understanding research trends on BPSD field is important to appraise and guide future research.

OBJECTIVES

The purpose of this study was to analyze the 100 most cited articles about BPSD using bibliometrics, and to describe the current trends, patterns, types, area of work done and lacunae.

MATERIAL AND METHODS

The Google Scholar database was searched using a freely available software, Publish or Perish for retrieving 100 most cited articles on BPSD following PRISMA guidelines. Information related to citations metrics, journals, country of origin, institution of origin, study design and primary area of work was collected.

RESULTS

The total citation count ranged from 75 to 9096 [mean(SD):343.86(946.24)]. The citation count per year ranged from 3.94 to 303.3. The normalised citation count ranged from 0.09 to 3.57. The maximum number of articles were published in 2005 and 2013 (n = 9 each). John Hopkins University (n = 9) and International Journal of Geriatric Psychiatry (n = 24) contributed to the maximum articles. Nearly 90 % of articles came from high income countries.

CONCLUSION

Cross-sectional studies and systematic reviews were the most common study methods in the BPSD research. Epidemiological and interventional are the most studied primary areas. Lack of adequate studies with RCT design, qualitative studies and areas including predictors of BPSD, quality of life, cost analysis and staff training was observed. There is markedly lesser research from middle and low-income countries on BPSD.

APOE Haplotype Phasing Using ONT Long-Read Sequencing Reveals Two Common ε3 and ε4 intragenic haplotypes in the Spanish Population

Background

The apolipoprotein E (APOE) gene is a key genetic determinant of Alzheimer's disease (AD) risk, with the ε4 allele significantly increasing susceptibility. While the pathogenic effects of the ε4 allele are well established, the functional impact of distinct haplotype configurations within the broader ε3 and ε4 backgrounds remains poorly understood. This study investigates the role of intragenic sub haplotypes in modulating APOE expression and their potential influence on AD progression.

Methods

We utilized Oxford Nanopore Technology (ONT) long-read sequencing to phase variants within a 4-kilobase comprising the APOE locus in a cohort of 1,265 individuals with known APOE genotypes. We evaluated the impact of the identified intragenic haplotypes on APOE protein levels in cerebrospinal fluid (CSF) using the Olink platform, adjusting for demographic and molecular covariates. Statistical modeling was employed to assess the independent effects of these haplotypes alongside traditional APOE genotypes. Additionally, their influence on dementia progression in mild cognitive impairment (MCI) subjects was analyzed using adjusted Cox proportional hazards models.

Results

Our analysis identified 48 Single Nucleotide Variants (SNVs) within a 4-kilobase region containing the APOE gene, including nine novel variants. Phasing of variants within the APOE locus revealed 59 unique haplotypes in the Spanish population, which were grouped into five major haplogroups-ε2, ε3A, ε3B, ε4A, and ε4B-including two common haplogroups for each of the ε3 and ε4 isoforms. The ε4A haplogroup was associated with a significant decrease in APOE ε4 protein levels in CSF (p = 0.004), suggesting a regulatory mechanism that may mitigate the toxic gain-of-function effect typically attributed to the ε4 allele. Conversely, the ε3B haplogroup was linked to increased APOE ε3 protein levels in ε3/ε4 carriers (p = 0.025), potentially serving a compensatory role.These effects were independent of overall APOE genotype and remained significant after adjusting for covariates. Both haplogroups (ε4A and ε3B) demonstrated protective effects in the progression from MCI to dementia, underscoring their potential relevance in Alzheimer's disease.

Conclusions

This study provides new insights into the intragenic allelic variability of the APOE gene, demonstrating that intragenic APOE haplogroups within the ε3 and ε4 backgrounds can modulate APOE isoform expression in ways that might modulate AD. Our findings highlight the importance of considering haplotype-specific effects when interpreting the functional impact of APOE and in designing targeted therapeutic strategies. Further research is needed to explore the broader regulatory network of the APOE locus and its interaction with neighboring loci in the 19q13 region.

Minimal clinically important differences for treatment of hallucinations in Parkinson's disease and dementia with Lewy bodies

BACKGROUND

Hallucinations are common and distressing symptoms in Parkinson's disease (PD). Treatment response in clinical trials is measured using validated questionnaires, including the Scale for Assessment of Positive Symptoms-Hallucinations (SAPS-H) and University of Miami PD Hallucinations Questionnaire (UM-PDHQ). The minimum clinically important difference (MCID) has not been determined for either scale. This study aimed to estimate a range of MCIDs for SAPS-H and UM-PDHQ using both consensus-based and statistical approaches.

METHODS

A Delphi survey was used to seek opinions of researchers, clinicians, and people with lived experience. We defined consensus as agreement ≥75%. Statistical approaches used blinded data from the first 100 PD participants in the Trial for Ondansetron as Parkinson's Hallucinations Treatment (TOP HAT, NCT04167813). The distribution-based approach defined the MCID as 0.5 of the standard deviation of change in scores from baseline at 12 weeks. The anchor-based approach defined the MCID as the average change in scores corresponding to a 1-point improvement in clinical global impression-severity scale (CGI-S).

RESULTS

Fifty-one researchers and clinicians contributed to three rounds of the Delphi survey and reached consensus that the MCID was 2 points on both scales. Sixteen experts with lived experience reached the same consensus. Distribution-defined MCIDs were 2.6 points for SAPS-H and 1.3 points for UM-PDHQ, whereas anchor-based MCIDs were 2.1 and 1.3 points, respectively.

CONCLUSIONS

We used triangulation from multiple methodologies to derive the range of MCID estimates for the two rating scales, which was between 2 and 2.7 points for SAPS-H and 1.3 and 2 points for UM-PDHQ.

Intrinsic capacity in patients with dementia with Lewy bodies compared with those with Alzheimer's disease: A cross-sectional study

OBJECTIVES

Intrinsic capacity (IC), the composite of all the physical and mental capacities of an individual, has never been studied in patients with dementia with Lewy bodies (DLB). As IC decline is associated with the risk of frailty, functional decline and disability and is potentially reversible after targeted interventions, a monitoring and specific management of IC decline in patients with DLB could promote healthy aging in this population. The aim of this cross-sectional study was to describe the frequency of IC decline in DLB and to compare it with AD.

DESIGN

A single-center cross-sectional study.

SETTING

This study was carried out in a memory clinic between 2015 and 2023 based on the MEMORA cohort.

PARTICIPANTS

Patients with a diagnosis of AD or probable DLB and a comprehensive geriatric assessment.

MEASUREMENTS

IC was assessed according to the WHO model in 4 domains: vitality assessed by the Mini Nutritional Assessment (MNA), locomotion assessed by the Short Physical Performance Battery (SPPB), psychology assessed by the Geriatric Depression Scale 4-items (GDS-4 items), and hearing assessed by the Hearing, Vision, Equilibrium and Cognition (HVEC) scale.

RESULTS

A total of 798 patients (154 with probable DLB and 644 with AD) were included, and the mean age was 81.4 years (SD 6.33). Compared with AD patients, DLB patients had significantly more impaired IC in all domains, with greater risks of impaired vitality (odds ratio (OR) 2.43, 95% confidence interval (CI) 1.60-3.72), locomotion (OR 3.50, 95% CI 2.15-5.90), psychology (OR 2.60, 95% CI 1.73-3.92) and hearing (OR 2.30, 95% CI 1.53-3.49), according to the adjusted models. Similarly, when IC domains were considered linear variables, IC across all domains was significantly lower in the DLB group than in the AD group.

CONCLUSION

This study revealed that DLB patients presented a greater decrease in IC than did AD patients across all domains. In memory clinics, DLB patients could be offered systematic and early IC monitoring and personalized interventions.

Application of mini-mental state examination and Montreal Cognitive Assessment in the diagnosis of dementia with Lewy bodies and Alzheimer's disease

BACKGROUND

Dementia with Lewy Bodies (DLB) and Alzheimer's disease (AD) are two types of dementia with a relatively high incidence, and their clinical manifestations are easily confused. However, the cognitive impairment characteristics of the two diseases are different, and the results of cognitive assessment can help the diagnosis of the disease.

OBJECTIVE

To explore the different characteristics of Mini-mental State Examination (MMSE) and Montreal Cognitive Assessment Scale (MoCA) in DLB and AD patients, and to explore potential markers to distinguish AD and DLB.

METHODS

This study included 66 patients with DLB, 81 with AD, and 58 cognitively normal subjects. All of them completed MMSE, MoCA, and Clinical Dementia Rating (CDR).

RESULTS

Compared with NC, both DLB and AD participants demonstrated statistically lower scores in the total and subitem domains of MMSE and MoCA (p < 0.05). When CDR was less than 2, DLB patients had better performance than AD in two subtests including memory and orientation (p < 0.05), demonstrated worse performance in most subtest including executive function, writing, visuospatial abilities, and attention (p < 0.05). Nonetheless, no notable distinction in scores existed for the DLB and AD groups with a CDR score of 2 (p > 0.05).

CONCLUSION

We observed distinct cognitive performances in subjects from both the DLB and AD groups across different stages of dementia. Our study confirms the high value of MMSE and MoCA in distinguishing patients with DLB and AD in the early stages of the disease, and they can improve the differential diagnosis of DLB and AD.

Dopaminergic changes in the subgenual cingulate cortex in dementia with lewy bodies associates with presence of depression

In addition to the core clinical features of fluctuating cognition, visual hallucinations, and parkinsonism, individuals with dementia with Lewy bodies (DLB) frequently experience chronic and debilitating major depression. Treatment of depression in DLB is hampered by a lack of available effective therapies and standard serotonergic medication for major depressive disorder (MDD) is typically ineffective. Dysfunction of dopaminergic neurotransmission contributing to anhedonia and loss of motivation has been described in MDD. The subgenual anterior cingulate cortex (sgACC) is important in mood regulation and in the symptomatic expression of depression, displaying structural, functional and metabolic abnormalities in MDD. To assess dopaminergic and serotonergic synaptic changes in DLB, post mortem sgACC tissue from DLB donors with and without depression was investigated using high-resolution stimulated emission depletion (STED) microscopy, as well as Western and dot blotting techniques. STED imaging demonstrated the presence of α-synuclein within individual dopaminergic terminals in the sgACC, α-synuclein presence showing a significant positive correlation with increased synaptosomal associated protein 25 kDa (SNAP25) volumes in depressed DLB cases. A reduction in dopaminergic innervation in the sgACC was observed in DLB cases with depression compared to controls (p < 0.001), but not in non-depressed DLB donors, along with reduced levels of multiple dopaminergic markers and receptors. Limited alterations were observed in serotonergic markers. Our work demonstrates a role for dopaminergic neurotransmission in the aetiology of depression in DLB. Careful and selective targeting of dopaminergic systems in the sgACC may be a therapeutic option for treatment of depression in DLB.

A reciprocal relationship between markers of genomic DNA damage and alpha-synuclein pathology in dementia with Lewy bodies

BACKGROUND

DNA damage and DNA damage repair (DDR) dysfunction are insults with broad implications for cellular physiology and have been implicated in various neurodegenerative diseases. Alpha-synuclein (aSyn), a pre-synaptic and nuclear protein associated with neurodegenerative disorders known as synucleinopathies, has been associated with DNA double strand break (DSB) repair. However, although nuclear aSyn pathology has been observed in cortical tissue of dementia with Lewy body (DLB) cases, whether such nuclear pathology coincides with the occurrence of DNA damage has not previously been investigated. Moreover, the specific types of DNA damage elevated in DLB cases and the contribution of DNA damage towards Lewy body (LB) formation is unknown.

METHODS

DNA damage and aSyn pathology were assessed in fixed lateral temporal cortex from clinically and neuropathologically confirmed DLB cases and controls, as well as in cortical tissue from young 3-month-old presymptomatic A30P-aSyn mice. Frozen lateral temporal cortex from DLB and control cases was subject to nuclear isolation, western blotting, aSyn seed amplification and proteomic characterisation via mass spectrometry.

RESULTS

We detected seed-competent nuclear aSyn, and elevated nuclear serine-129 phosphorylation in DLB temporal cortex, alongside the accumulation of DSBs in neuronal and non-neuronal cellular populations. DNA damage was also present in cortical tissue from presymptomatic A30P mice, demonstrating it is an early insult closely associated with pathogenic aSyn. Strikingly, in postmortem DLB tissue, markers of genomic DNA damage-derived cytoplasmic DNA (CytoDNA) were evident within the majority of LBs examined. The observed cellular pathology was consistent with nuclear upregulation of associated DDR proteins, particularly those involved in base excision repair and DSB repair pathways.

CONCLUSIONS

Collectively our study demonstrates the accumulation of seed-competent pathological nuclear associated aSyn, alongside nuclear DNA damage and the potential involvement of DNA damage derived cytoDNA species in cytoplasmic aSyn pathology. Ultimately, our study supports the hypothesis of a reciprocal relationship between aSyn pathology and nuclear DNA damage and highlights a potential underlying role for DNA damage in pathological mechanisms relevant to DLB, as well as other synucleinopathies, opening novel possibilities for diagnosis and treatment.

Exploring the origins of frequent tau-PET signal in vermal and adjacent regions

PURPOSE

Off-target binding remains a significant challenge in tau-PET neuroimaging. While off-targets including monoamine oxidase enzymes and neuromelanin-containing cells have been identified, recent studies indicated a relevant binding of novel tau tracers to melanin-containing structures. To date, little is known about the effect of melanocytes in the meninges on tracer signals in brain PET data. Thus, we aimed to identify the target structure causal for the frequently observed [18F]PI-2620 PET signal in the vermis and adjacent cerebellar regions.

METHODS

274 participants underwent dynamic [18F]PI-2620 tau-PET: 3/4R-tauopathies (n = 85), 4R-tauopathies (n = 147), tau-negative disease controls (n = 24), and healthy controls (n = 18). Standardized uptake value ratio (SUVR) and kinetic parameters including the distribution volume ratio (DVR), tracer clearance (k2) and relative perfusion (R1), were compared among the cohorts and sexes using the Automated Anatomical Labelling (AAL) atlas. Age and p-Tau levels in cerebrospinal fluid (CSF) were assessed for their relationship with vermal tau-PET signal. Furthermore, we combined autoradiographic and histochemical experiments on post-mortem brain tissue of deceased patients (n = 9).

RESULTS

Male participants revealed higher mean vermal [18F]PI-2620 DVR (0.95 ± 0.13; vs. females 0.88 ± 0.10, p < 0.0001). Sex-related differences were most pronounced in the 3/4R-tauopathy cohort (p < 0.0001). Mean SUVRVer/Cbl, k2 and correlation analyses of kinetic parameters did not differ among groups. Histological assessments revealed co-localization of leptomeningeal pigmented cells with strong autoradiography signal spots within the vermal fissures. Tau-related autoradiography signals, age or p-Tau levels did not correlate significantly with tau-PET signals. Iron deposits did not cause relevant autoradiography signals in the vermis.

CONCLUSION

Leptomeningeal melanocytes are the primary target structure for [18F]PI-2620 PET binding in anterior vermis, whereas iron and tau deposits do not contribute significantly.

Neuroimaging of psychosis, agitation, and affective disturbance in Alzheimer's disease, dementia with Lewy bodies, and mild cognitive impairment

OBJECTIVES

This study identifies neuropsychiatric syndromes and investigates their relationship with neuroimaging in Alzheimer's disease dementia (AD), dementia with Lewy bodies (DLB), and mild cognitive impairment (MCI).

METHODS

Magnetic resonance imaging and perfusion single-photon emission computed tomography data were collected for 281, 68, and 180 patients with AD, DLB, and MCI, respectively, from three Japanese institutions. Neuropsychiatric Inventory was used for exploratory factor analysis in each group. Statistical Parametric Mapping was exploited to reveal the relationships between each factor score and cerebral volume or perfusion with age, sex, dementia severity, and the other factor scores as covariates.

RESULTS

Three factors (psychosis, agitation, and affective disturbance) were extracted for AD. For DLB, nighttime behavior and aberrant motor behavior were extracted as independent symptoms with the same three factors. Four factors (psychosis, agitation, anxiety, and apathy) were extracted for MCI. A positive relationship between agitation and cerebral volume in the left middle frontal gyri and left caudate was observed in AD. In DLB, agitation was positively correlated with cerebral perfusion in the left dominant regions, including the middle frontal gyri and caudate. Psychosis and perfusion were negatively correlated in the left extent regions, including the temporo-parieto-occipital lobe, insula, and inferior frontal gyri in DLB. Psychosis was significantly associated with lower perfusion in the bilateral occipital lobes, whereas apathy was significantly correlated with a lower volume of the right dominant bilateral frontal lobes in MCI.

CONCLUSIONS

Three neuropsychiatric syndromes - psychosis, agitation, and affective disturbance - may heterogeneously associate with AD, DLB, and MCI.

Sleep and Prodromal Synucleinopathies

α-synucleinopathies are a complex group of progressive neurodegenerative disorders with an increasingly recognized long prodromal period, during which sleep dysfunction is a hallmark. Sleep disorders during the prodromal synucleinopathy period, primarily isolated rapid eye movement (REM) sleep behavior disorder (iRBD) and daytime hypersomnolence correlate best with the recently proposed "body-first" Lewy body disease progression. iRBD is the most widely recognized form of prodromal α-synucleinopathy, and patients with iRBD show abnormal α-synuclein in tissues and biofluids even in the absence of cognitive or motor symptoms. More importantly, individuals with iRBD have an elevated risk for near-term development of a clinically diagnosable symptomatic synucleinopathy. Other sleep disorders such as hypersomnia and circadian rhythm dysfunction also occur across the synucleinopathy spectrum, although their prognostic significance is less well understood than iRBD. Finally, isolated REM sleep without atonia may represent an even earlier stage of prodromal synucleinopathy, but further studies are needed.

Domestic violence in Lewy body dementia: A national study

A descriptive study using a transversal national online survey to evaluate the prevalence and characteristics of behavioral and psychological symptoms (BPSD) of dementia with Lewy bodies (DLB), and specifically, the perpetration of violent acts against primary caregivers. 196 responses, obtained in one month, were analyzed. Delirium, hallucinations, anxiety, and apathy were the most frequently reported BPSD symptoms (over 80% of responders). Primary caregivers expressed the highest degree of distress from agitation and aggressive behavior. Moreover, 45.9% of primary caregivers reported being the target of violent behaviors from DLB patients. No statistical association was found between the presence of BPSD and violent acts.

Alzheimer's disease neuropathology and its estimation with fluid and imaging biomarkers

Alzheimer's disease (AD) is neuropathologically characterized by the extracellular deposition of the amyloid-β peptide (Aβ) and the intraneuronal accumulation of abnormal phosphorylated tau (τ)-protein (p-τ). Most frequently, these hallmark lesions are accompanied by other co-pathologies in the brain that may contribute to cognitive impairment, such as vascular lesions, intraneuronal accumulation of phosphorylated transactive-response DNA-binding protein 43 (TDP-43), and/or α-synuclein (αSyn) aggregates. To estimate the extent of these AD and co-pathologies in patients, several biomarkers have been developed. Specific tracers target and visualize Aβ plaques, p-τ and αSyn pathology or inflammation by positron emission tomography. In addition to these imaging biomarkers, cerebrospinal fluid, and blood-based biomarker assays reflecting AD-specific or non-specific processes are either already in clinical use or in development. In this review, we will introduce the pathological lesions of the AD brain, the related biomarkers, and discuss to what extent the respective biomarkers estimate the pathology determined at post-mortem histopathological analysis. It became evident that initial stages of Aβ plaque and p-τ pathology are not detected with the currently available biomarkers. Interestingly, p-τ pathology precedes Aβ deposition, especially in the beginning of the disease when biomarkers are unable to detect it. Later, Aβ takes the lead and accelerates p-τ pathology, fitting well with the known evolution of biomarker measures over time. Some co-pathologies still lack clinically established biomarkers today, such as TDP-43 pathology or cortical microinfarcts. In summary, specific biomarkers for AD-related pathologies allow accurate clinical diagnosis of AD based on pathobiological parameters. Although current biomarkers are excellent measures for the respective pathologies, they fail to detect initial stages of the disease for which post-mortem analysis of the brain is still required. Accordingly, neuropathological studies remain essential to understand disease development especially in early stages. Moreover, there is an urgent need for biomarkers reflecting co-pathologies, such as limbic predominant, age-related TDP-43 encephalopathy-related pathology, which is known to modify the disease by interacting with p-τ. Novel biomarker approaches such as extracellular vesicle-based assays and cryptic RNA/peptides may help to better detect these co-pathologies in the future.

Interrogating DNA methylation associated with Lewy body pathology in a cross brain-region and multi-cohort study

Lewy body (LB) diseases are an umbrella term encompassing a range of neurodegenerative conditions all characterized by the hallmark of intra-neuronal α-synuclein associated with the development of motor and cognitive dysfunction. In this study, we have conducted a large meta-analysis of DNA methylation across multiple cortical brain regions, in relation to increasing burden of LB pathology. Utilizing a combined dataset of 1239 samples across 855 unique donors, we identified a set of 30 false discovery rate (FDR) significant loci that are differentially methylated in association with LB pathology, the most significant of which were located in UBASH3B and PTAFR, as well as an intergenic locus. Ontological enrichment analysis of our meta-analysis results highlights several neurologically relevant traits, including synaptic, inflammatory and vascular alterations. We leverage our summary statistics to compare DNA methylation signatures between different neurodegenerative pathologies and highlight a shared epigenetic profile across LB diseases, Alzheimer's disease and Huntington's disease, although the top-ranked loci show disease specificity. Finally, utilizing summary statistics from previous large-scale genome-wide association studies we report FDR significant enrichment of DNA methylation differences with respect to increasing LB pathology in the SNCA genomic region, a gene previously associated with Parkinson's disease and dementia with Lewy bodies.

Sympathetic and parasympathetic subtypes of body-first Lewy body disease observed in postmortem tissue from prediagnostic individuals

Recent studies suggest the existence of brain-first and body-first subtypes within the Lewy body disorder (LBD) spectrum, including Parkinson's disease. These studies primarily focused on α-synuclein propagation through the parasympathetic vagal and olfactory bulb routes, leaving the possibility of a sympathetic nervous system spreading route unexplored. In the present study, we analyzed two postmortem datasets, which included 173 and 129 cases positive for Lewy pathology. We observed a clear distinction between brain-first and body-first subtypes in early prediagnostic cases with mild Lewy pathology. Brain-first cases displayed minimal peripheral organ pathology in prediagnostic phases, contrasting with marked autonomic involvement in prediagnostic body-first cases. Utilizing the SuStaIn machine learning algorithm, we identified two distinct body-first subtypes, one with vagal predominance and another with sympathetic predominance, in equal proportions. Our study supports the existence of three prediagnostic LBD subtypes and highlights the sympathetic nervous system alongside the parasympathetic system in LBD onset and progression.

Probe-dependent Proximity Profiling (ProPPr) Uncovers Similarities and Differences in Phospho-Tau-Associated Proteomes Between Tauopathies

BACKGROUND

Tauopathies represent a diverse group of neurodegenerative disorders characterized by the abnormal aggregation of the microtubule-associated protein tau. Despite extensive research, the mechanisms underlying the diversity of neuronal and glial tau pathology in different tauopathies are poorly understood. While there is a growing understanding of tauopathy-specific differences in tau isoforms and fibrillar structures, the specific composition of heterogenous tau lesions remains unknown. Here we study the protein composition of tau aggregates in four major tauopathies: Alzheimer's disease (AD), corticobasal degeneration (CBD), Pick's disease (PiD), and progressive supranuclear palsy (PSP).

METHODS

We developed an approach for in situ proximity labeling and isolation of aggregate-associated proteins using glass slides with formalin-fixed paraffin-embedded (FFPE) human postmortem brain tissue, termed Probe-dependent Proximity Profiling (ProPPr). We used ProPPr for the analysis of proteomes associated with AT8-positive cellular lesions from frontal cortices. Isolated proximity proteomes were analyzed by data-independent acquisition mass spectrometry. Co-immunofluorescence staining and quantitative data analysis for selected proteins in human brain tissue was performed to further investigate associations with diverse tau pathologies.

RESULTS

Proteomics data analysis identified numerous common and tauopathy-specific proteins associated with phospho-tau aggregates. Extensive validations of candidates through quantitative immunofluorescence imaging of distinct aggregates across disease cases demonstrate successful implementation of ProPPr for unbiased discovery of aggregate-associated proteins in in human brain tissue. Our results reveal the association of retromer complex component vacuolar protein sorting-associated protein 35 (VPS35) and lysosome-associated membrane glycoprotein 2 (LAMP2) with specific types of phospho-tau lesions in tauopathies. Furthermore, we discovered a disease-specific association of certain proteins with distinct pathological lesions, including glycogen synthase kinase alpha (GSK3α), ferritin light chain (FTL), and the neuropeptide precursor VGF. Notably, the identification of FTL-positive microglia in CBD astrocytic plaques indicate their potential role in the pathogenesis of these lesions.

CONCLUSIONS

Our findings demonstrate the suitability of the ProPPr approach in FFPE brain tissue for unbiased discovery of local proteomes that provide valuable insights into the underlying proteomic landscape of tauopathies, shedding light on the molecular mechanisms underlying tau pathology. This first comprehensive characterization of tau-associated proteomes in a range of distinct tauopathies enhances our understanding of disease heterogeneity and mechanisms, informing strategies for the development of diagnostic biomarkers and targeted therapies.

Key motor and non-motor features in early dementia with Lewy bodies

Objective

The objective of our study was to characterize early-stage dementia with Lewy bodies (DLB) focusing on motor and non-motor symptoms.

Methods

This cross-sectional study prospectively included newly diagnosed DLB patients within 3 years of cognitive symptom onset. Comparisons were made with individuals with Parkinson's disease (PD), Alzheimer's disease (AD), and controls. Demographic and clinical data were collected, and motor and non-motor symptoms were assessed using structured interviews and validated scales and questionnaires.

Results

A total of 107 participants were included (23 DLB, 27 PD, 26 AD, and 31 controls). DLB patients (median age 75 years, median disease duration since diagnosis 2 months) commonly reported motor symptoms, including gait disturbances (91.3%), tremor (73.9%), and bradykinesia (87%), with tremor being predominantly unilateral (76.5%) and action-type (52.9%). The most frequent motor subtype was akinetic-rigid (52.2%). Motor symptoms were similar to PD, except for more frequent falls (34.8% vs. 11.1%, p = 0.044) and gait disturbances in DLB patients (91.3% vs. 63%, p = 0.019). Non-motor symptoms, particularly visual hallucinations and neuropsychiatric symptoms were more prevalent in DLB than in PD, while sleep and autonomic symptoms were similar. An abnormal orthostatic test was more frequent in DLB than in PD (45.5% vs. 11.5%, p < 0.008). Compared to AD, all non-motor symptoms were significantly more frequent in DLB. Finally, DLB patients had lower functional independence and quality of life than both PD and AD (p < 0.0001).

Conclusion

Early-stage DLB closely resembles PD in motor symptoms but has more neuropsychiatric non-motor symptoms compared to PD and overall non-motor symptoms than AD.

Brain Perfusion, Atrophy, and Dopaminergic Changes in Amyloid Negative Logopenic Primary Progressive Aphasia

Although most cases of logopenic variant primary progressive aphasia (lvPPA) are caused by Alzheimer's disease (AD), Lewy body disease (LBD) has also been reported. We assessed brain perfusion, atrophy, dopamine transporter (DAT) uptake, and language function among patients with lvPPA based on beta-amyloid. Thirty-three patients with lvPPA and 28 healthy controls (HCs) underwent MRI, 18F-florbetaben PET, and early- and late-phase DAT PET. All patients completed a language test. General linear models were applied to investigate the association of brain imaging with the aphasia quotient (AQ) and repetition scores. 20 (60.6%) and 13 (39.4%) of the lvPPA patients were amyloid-positive (lvPPAA+) and -negative (lvPPAA-), respectively. Language function was comparable between groups. Compared to HCs, the lvPPAA+ had lower perfusion across widespread brain regions, the lvPPAA- had lower perfusion in the left supramarginal and angular gyri, and both groups had lower DAT in the left caudate and bilateral substantia nigra. In the lvPPAA-, AQ and repetition scores were positively correlated with perfusion in the left temporal and inferior parietal cortices, with perfusion in the left supramarginal gyrus mediating the effect of left substantia nigra DAT. Although AD is the most common underlying pathology of lvPPA, LBD may contribute to the logopenic phenotype.

Apathy in Dementia: A Pilot Study Providing Insights from Neuropsychiatric and Radiological Perspectives

Background: Apathy is a common neuropsychiatric symptom in all stages of dementia, significantly complicating patient management. This study examines the prevalence of apathy across Alzheimer's Disease (AD), Lewy Body Dementia (LBD), Frontotemporal Dementia (FTD), and Vascular Dementia (VD) and explores its associations with cognitive functions, neuropsychiatric symptoms, and magnetic resonance imaging (MRI) findings. Methods: This retrospective, cross-sectional study included 200 patients diagnosed with AD, LBD, FTD, and VD along with 100 healthy controls (HCs). Apathy was assessed using the Apathy Evaluation Scale. Depression and anxiety in patients were evaluated using the Geriatric Depression Scale and the Geriatric Anxiety Scale, respectively. Cognitive function was measured with the Mini-Mental State Examination (MMSE) and Addenbrooke's Cognitive Examination-Revised (ACE-R). MRI findings were evaluated using atrophy scales that are routinely utilized in dementia assessments. Results: Apathy was significantly more prevalent in dementia and MCI patients compared to HC. However, there were no significant differences in apathy prevalence among dementia subtypes. Apathy showed no significant correlation with depression, anxiety, or cognitive performance. Notably, MRI analysis revealed a strong association between apathy and orbitofrontal (OF) sulci atrophy. Conclusions: Apathy is a critical symptom in dementia, linked to OF atrophy and presenting challenges in management. These findings emphasize the importance of integrating apathy assessments in clinical practice. Larger, longitudinal studies are needed to further clarify the pathophysiology and management of apathy in dementia.

A genome-wide association study identifies a novel East Asian-specific locus for dementia with Lewy bodies in Japanese subjects

BACKGROUND

Dementia with Lewy bodies (DLB) is the second most common type of degenerative dementia in older patients. As with other multifactorial diseases, the pathogenesis results from interactions of environmental and genetic factors. The genetic basis of DLB is not yet fully understood. Recent genomic analyses of DLB in Caucasian cohorts identified genetic susceptibility loci for DLB, but the comprehensive genomic analysis in Asians was still not performed.

METHODS

We conducted a genome-wide association study (GWAS) in Japanese subjects (211 DLB cases and 6113 controls) to clarify the genetic architecture of DLB pathogenesis.

RESULTS

We identified the East Asian-specific DHTKD1 locus (rs138587229) on chromosome 10 with genome-wide significance (GWS; P = 3.27 × 10-8) and the ICOS/PARD3B locus on chromosome 2 with suggestive significance (P = 3.95 × 10-7) as novel DLB genetic risk loci. We also confirmed the APOE locus (rs429358, P < 5.0 × 10-8), a known risk locus for DLB and Alzheimer's disease in Caucasians. The DHTKD1 locus was associated with the gene expression of SEC61A2 and showed a causal relationship with cholinesterase levels. In a trans-ethnic meta-analysis that included Japanese, UK Biobank, and other Caucasian GWAS, we confirmed the risk for DLB at APOE and SNCA loci with GWS. Transcriptome-wide association analysis identified ZNF155 and ZNF284 in the brain cortex and GPRIN3 in the substantia nigra as putative causal genes for DLB.

CONCLUSIONS

This is the first GWAS for DLB in East Asians, and our findings provide new biological and clinical insights into the pathogenesis of DLB.

The investigation of peripheral inflammatory and oxidative stress biomarkers in dementia with Lewy Bodies, compared with Alzheimer's Disease, and mild cognitive impairment

Although inflammation and oxidative stress have been increasingly recognised as components of Alzheimer's disease (AD) and Parkinson's disease (PD) pathologies. Few studies have investigated peripheral inflammation, and none have examined oxidative stress in Dementia with Lewy bodies (DLB). The purpose of our study was to characterize and compare those biomarkers in DLB with those in AD and amnestic mild cognitive impairment (aMCI). Plasma samples were obtained from Chinese patients with DLB (n = 50), AD (n = 59), and aMCI (n = 30), and healthy controls (HCs) (n = 54). Peripheral inflammatory biomarkers, including interferon-gamma (IFN-γ), interleukins (IL-1β, IL-2, IL-4, IL-6, IL-10, IL-12p70, IL-17A), tumor necrosis factor-alpha (TNF-α), and C-reactive protein (CRP). Oxidative stress markers, such as superoxide dismutase (SOD), malondialdehyde (MDA), and glutathione peroxidase (GSH-Px), were also assessed. The findings revealed that DLB patients had higher IL-6 levels than AD and HCs and elevated IL-10 and IL-17A levels compared to HCs. In terms of oxidative stress, the levels of SOD were significantly lower and MDA were significantly higher in the DLB and AD compared with HCs. Significant positive correlations were found between Unified Parkinson's Disease Rating Scale (UPDRS) scores and CRP levels. Our study identifies a unique peripheral immune and oxidative stress profile in DLB, characterized by elevated IL-6, MDA, and reduced SOD levels, distinguishing it from AD. These findings, linked to α-synuclein (α-Syn) pathology, provide novel insights into DLB mechanisms and highlight potential biomarkers for disease monitoring, targeted therapies, and future clinical trials.

The causal association between resting state intrinsic functional networks and neurodegeneration

Alterations of resting state intrinsic functional networks have been associated with neurodegenerative diseases even before the onset of cognitive symptoms. Emerging hypotheses propose a role of resting state intrinsic functional networks alterations in the risk or vulnerability to neurodegeneration. It is unknown whether intrinsic functional network alterations can be causal for neurodegenerative diseases. We sought to answer this question using two-sample Mendelian randomization. Using the largest genome-wide association study of resting state intrinsic functional connectivity (n = 47 276), we generated genetic instruments (at the significance level 2.8 ×10-11) to proxy resting state intrinsic functional network features. Based on the known brain regions implicated in different neurodegenerative diseases, we generated genetically proxied resting state intrinsic functional features and tested their association with their paired neurodegenerative outcomes: features in parieto-temporal regions and Alzheimer dementia (111 326 cases, 677 663 controls); frontal region and frontotemporal dementia (2154 cases, 4308 controls); temporal pole region and semantic dementia (308 cases, 616 controls), and occipital region with Lewy body dementia (LBD) (2591 cases, 4027 controls). Major depressive disorder outcome (170 756 cases, 329 443 controls) was included as a positive control and tested for its association with genetically proxied default mode network (DMN) exposure. Inverse-variance weighted analysis was used to estimate the association between the exposures (standard deviation units) and outcomes. Power and sensitivity analyses were completed to assess the robustness of the results. None of the genetically proxied functional network features were significantly associated with neurodegenerative outcomes (adjusted P value >0.05), despite sufficient calculated power. Two resting state features in the visual cortex showed a nominal level of association with LBD (P = 0.01), a finding that was replicated using a different instrument (P = 0.03). The genetically proxied DMN connectivity was associated with the risk of depression (P = 0.024), supporting the validity of the genetic instruments. Sensitivity analyses were supportive of the main results. This is the first study to comprehensively assess the potential causal effect of resting state intrinsic functional network features on the risk of neurodegeneration. Overall, the results do not support a causal role for the tested associations. However, we report a nominal association between visual network connectivity and Lewy body dementia that requires further evaluation.