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

White matter hyperintensities in dementia with lewy bodies and posterior cortical atrophy

Dementia with Lewy bodies (DLB) and posterior cortical atrophy (PCA) are neurodegenerative disorders that can overlap clinically and in patterns of regional hypometabolism and show elevated white matter hyperintensity (WMH) burden. Little is known about the regional WMH burden in DLB patients without any interference of AD pathology and how these patterns compare to PCA patients. Twenty-two amyloid-negative DLB patients, 40 amyloid-positive PCA patients, and 49 amyloid-negative cognitively unimpaired (CU) healthy individuals were recruited at Mayo Clinic, Rochester, MN. They underwent a 3 T head MRI, a Pittsburgh Compound B (PiB) PET scan, and a fluid-attenuated inversion recovery scan (FLAIR). The relationship between regional WMH volume and diagnosis was evaluated while adjusting for age and sex. DLB showed greater periventricular WMH burden in the temporal, occipital, and frontal lobes and greater WMH burden in the posterior corpus callosum compared to CU. PCA showed greater subcortical WMH burden in temporal, parietal, and occipital lobes, and greater periventricular WMH burden in the temporal, occipital, and frontal lobes, compared to CU. On comparing both dementia groups, PCA showed greater subcortical WMH burden in the temporal and occipital lobes compared to DLB, while DLB showed greater WMH burden in the posterior corpus callosum compared to PCA. Hence, DLB and PCA are both associated with periventricular WMHs, with deep subcortical WMHs being more characteristic of PCA, and callosal WMHs more characteristic of Aβ-negative DLB patients, suggesting different pathophysiological mechanisms underlying the development of WMHs in these two neurodegenerative diseases.

Clinical characteristics of pathological confirmed DLB without parkinsonism

INTRODUCTION

The misdiagnosis rate of Dementia with Lewy Bodies (DLB) remains high. Accurate diagnosis is paramount in the era of anti-amyloid therapy. The main objective of the current study is to elucidate early clinical features of pathologically confirmed DLB without parkinsonism (DLB-nP) that potentially resemble Alzheimer's disease (AD).

METHODS

We accessed the National Alzheimer's Coordinating Center database from 2005 to December 2022 data freeze and included 3159 Alzheimer's disease, 91 DLB-nP, and 307 DLB with parkinsonism (DLBP) cases. Diagnosis of AD and DLB were based on existing pathological criteria. First visit data was analyzed.

RESULTS

Clinician-determined memory impairment is common in DLB-nP (87.9 % vs. AD 97.4 %) but is associated with a higher risk of AD diagnosis. Misdiagnosis as AD in DLB-nP stands at 75.8 %. Visual hallucinations (VH) or hallucinations are the only variables favoring DLB-nP diagnosis, but they only account for 22 % and 14 % of the cohort, respectively. After patients with VH were removed from the model, the misdiagnosis rate as AD increased to 85.2 %, and nighttime behavior was the only variable found to favor DLB-nP diagnosis. Visuospatial dysfunction is more common in DLB-P than DLB-nP but does not distinguish DLB-nP from AD.

CONCLUSION

Amnestic presentation, while favoring AD diagnosis, is common in DLB without parkinsonism, and misdiagnosis is common. While VH remains the most prominent clinical feature for prompting DLB diagnosis, misdiagnosis becomes more profound in its absence during the early phase. In this study, exercising great caution during clinical assessment appears to be the fundamental way to minimize misdiagnosis for patients with amnestic presentation yet without parkinsonism and VH.

Stability and Accuracy of a Diagnosis of Parkinson Disease Over 10 Years

BACKGROUND AND OBJECTIVES

Accurate diagnosis of Parkinson disease (PD) remains challenging, with variability and clinical uncertainty, especially in nonspecialized settings. Despite advancements in diagnostic criteria and biological markers, misdiagnosis continues to affect patient care and research. This study aimed to assess the long-term diagnostic stability of PD and evaluate the accuracy of initial diagnoses over time in a large, consecutive cohort diagnosed by neurologists, with or without movement disorder specialization.

METHODS

We conducted a retrospective longitudinal analysis of patients diagnosed with PD between 2006 and 2020. Patient records were reviewed over a median follow-up period of 10 years, with more than half of the cohort tracked from motor symptom onset to death. Diagnostic evaluations included dopamine transporter (DAT) imaging and neuropathologic examinations for a subset of patients, based on clinical indications. Two movement disorder specialists cross-validated diagnoses through retrospective chart reviews.

RESULTS

The cohort included 1,626 patients (mean age 69.0 years, 44.1% female). Of these, 10.6% (n = 172) had their diagnoses revised by treating neurologists, and 2.7% (n = 44) were revised based on chart reviews or neuropathologic findings. The median time to diagnosis revision was 22 months (interquartile range = 43). The most common revised diagnoses were vascular parkinsonism, progressive supranuclear palsy, and multiple system atrophy, with 4.7% (n = 77) classified as clinically undetermined parkinsonism. In a secondary analysis separating PD and dementia with Lewy bodies (DLB), the revision rate increased to 17.7%. DAT imaging had been performed on 588 patients and was more frequently used in revised cases. Postmortem neuropathologic examinations had been conducted in only 3% of deceased patients, with 64% confirming the initial PD diagnosis.

DISCUSSION

This study demonstrates significant diagnostic instability in PD, with 13.3% of diagnoses revised, primarily within 2 years. When DLB is considered separately, the revision rate increases to 17.7%. Despite frequent DAT imaging and limited postmortem examinations, clinical uncertainty persists among practicing neurologists, contrasting with lower misdiagnosis rates in specialized centers. These findings highlight the need for systematic application of diagnostic criteria, regular reevaluation of diagnoses, more frequent autopsies, and the development of accessible diagnostic biomarkers.

Adult Neurogenesis in the Subventricular Zone of Patients with Huntington's and Parkinson's Diseases and following Long-Term Treatment with Deep Brain Stimulation

OBJECTIVE

Parkinson's and Huntington's diseases are characterized by progressive neuronal loss. Previous studies using human postmortem tissues have shown the impact of neurodegenerative disorders on adult neurogenesis. The extent to which adult neural stem cells are activated in the subventricular zone and whether therapeutic treatments such as deep brain stimulation promote adult neurogenesis remains unclear. The goal of the present study is to assess adult neural stem cells activation and neurogenesis in the subventricular zone of patients with Huntington's and Parkinson's diseases who were treated or not by deep brain stimulation.

METHODS

Postmortem brain samples from Huntington's and Parkinson's disease patients who had received or not long-term deep brain stimulation of the subthalamic nucleus were used.

RESULTS

Our results indicate a significant increase in the thickness of the subventricular zone and in the density of proliferating cells and activated stem cells in the brain of Huntington's disease subjects and Parkinson's disease patients treated with deep brain stimulation. We also observed an increase in the density of immature neurons in the brain of these patients.

INTERPRETATION

Overall, our data indicate that long-term deep brain stimulation of the subthalamic nucleus promotes cell proliferation and neurogenesis in the subventricular zone that are reduced in Parkinson's disease. Taken together, our results also provide a detailed characterization of the cellular composition of the adult human subventricular zone and caudate nucleus in normal condition and in Parkinson's and Huntington's diseases and demonstrate the plasticity of these regions in response to neurodegeneration. ANN NEUROL 2025;97:894-906.

Clinical Evolution of Neuropsychiatric Symptoms in Alzheimer's Disease and Dementia With Lewy Bodies in a Post-Mortem Cohort

BACKGROUND

Almost all patients with neurodegenerative dementias experience neuropsychiatric symptoms (NPS) but the timing and clinical course is highly variable.

METHODS

In a prospective cohort study in Western Norway, patients with a new diagnosis of mild dementia were assessed annually in the Neuropsychiatric Inventory (NPI) for up to 9 years until death. Patients with post-mortem neuropathological diagnoses of Alzheimer's disease (pAD) (n = 37), Lewy body disease (pLBD) (n = 14) or meeting criteria for both AD and LBD (mixed AD+LBD) (n = 11) were included in this study. Neuropathological assessment was performed according to standardised protocols and blind to clinical information. In mixed effects logistic regression, longitudinal change in NPS was explored across neuropathological diagnoses and substrates. Additionally, the odds of NPS early and late in disease was evaluated in logistic regression.

RESULTS

Early onset hallucinations were significantly more common in pLBD than pAD (OR 0.069 [95% CI 0.012-0.397], p = 0.003) or mixed AD+LBD (OR 0.09 [95% CI 0.010-0.771], p = 0.028) and there was a greater increase in the odds of hallucinations over time in pAD and AD+LBD than pLBD such that there was was no difference in the prevalence of late-onset hallucinations between pLBD, pAD or AD+LBD. Hallucinations early in disease were associated with higher LBD α-synuclein stages and neocortical LBD, in addition and sparser amyloid distribution. Higher density of amyloid plaques, tau tangles, cerebrovascular disease and increasing additional co-pathologies were associated with increasing odds of hallucinations over time.

CONCLUSIONS

LBD, without significant comorbid AD pathology, is associated with hallucinations early in the course of disease while multiple other pathologies may be implicated in aetiology of late-onset hallucinations. Hallucinations increase in AD+LBD as disease progresses, a trajectory more closely aligned with AD than LBD.

Practical Assessment of Neuropsychiatric Symptoms: Updated Reliability, Validity, and Cutoffs for the Neuropsychiatric Inventory Questionnaire

OBJECTIVES

To improve assessment of neuropsychiatric symptoms (NPS) by expanding the measurement properties of the Neuropsychiatric Inventory Questionnaire (NPI-Q).

DESIGN

Multicenter, longitudinal observational study.

SETTING

Several Alzheimer's Disease Research Centers (ADRCs).

PARTICIPANTS

Individuals (n = 45,274) who presented to an ADRC with a collateral and completed the NPI-Q.

MEASUREMENTS

The NPI-Q total severity score, four NPI-Q subscales, dementia stage, expert NPS rating, consensus rating of dementia syndrome, global cognitive screening, collateral rating of daily functioning, and self-rating of depression.

RESULTS

There was strong evidence of criterion validity with both dementia stage and expert NPS rating for the NPI-Q total severity index, which informed cutoffs and interpretive ranges. Furthermore, subscales had adequate classification of dementia syndromes and appropriate convergent relationships with cognition, daily functioning, and mood. There was good-to-excellent evidence of reliability for the NPI-Q total severity index over several years, and subscales had adequate-to-good reliability.

CONCLUSIONS

This is the first study to provide empirically established cutoffs, interpretive ranges, and evidence of reliability over a period longer than a month on the NPI-Q and its subscales. This will improve assessment of NPS in clinical and research contexts.

ARTICLE SUMMARY

Neuropsychiatric symptoms of neurodegeneration are increasingly understood as early disease markers with tremendous functional impact later in disease, but are often missed or misdiagnosed. The most common measure of these symptoms, the Neuropsychiatric Inventory Questionnaire (NPI-Q), does not have clinically actionable guidance, which this article provided. We established cutscores for several conditions and test-retest reliability over longer periods for the total score and subscales using a multicenter database.

A simple method to evaluate the pentagon copy test of the Mini-Mental State Examination for the differentiation of dementia with Lewy bodies

There are many commonalities between the clinical symptoms of dementia with Lewy bodies (DLB) and those of Alzheimer's disease (AD). The accurate differentiation of these two diseases is an important neuropsychological issue. The Mini-Mental State Examination (MMSE) is often used as a screening test for dementing disorders. We created evaluation items for the pentagon copy test of MMSE and developed a simple, highly accurate evaluation method for differentiating DLB in combination with conventional evaluation items such as the Qualitative Scoring MMSE Pentagon Test (QSPT). Subjects were divided into three groups: DLB (n = 119), AD (n = 50), and Normal (n = 26). The severities of DLB and AD ranged from mild cognitive impairment (MCI) to mild dementia. We compared the results of the pentagon copy test. We found that the rates of patients with abnormalities in "motor incoordination" and "gestalt destruction" were higher in the DLB group than the AD group. Furthermore, receiver operating characteristic curve analysis suggested the differentiation of DLB with high accuracy (sensitivity: 0.70, specificity: 0.78) using the criterion of patients meeting one of the following three characteristics: "the number of angles on QSPT: scores other than 4," "major tremor (Parkinsonism-related tremor) is present," and "gestalt destruction (distortion in overall coherence) is present." This evaluation method may be clinically useful for evaluating MCI to mild DLB patients because the burden on patients is low.

Distinct trajectories of subjective cognitive decline before diagnosis of neurocognitive disorders: Longitudinal modelling over 18 years

BACKGROUND

Subjective cognitive decline (SCD) is an established predictor of neurocognitive disorders (NCD) (i.e. mild cognitive impairment and dementia). Yet, its construct remains contentious. Many individuals with SCD do not progress to NCD, leading to an alternative term in the literature - 'functional cognitive disorders' - to describe the SCD experience in these individuals.

OBJECTIVES

To examine the distinct differences in trajectories of SCD between those who did and did not eventually develop NCD.

DESIGN

Case-control study.

SETTING

Alzheimer's Disease Centers across USA.

PARTICIPANTS

A total of 5,167 participants aged ≥50 years were followed up near-annually to evaluate for SCD and NCD (median follow-up=8.1 years; range=1.0-18.0). Cases were defined as those who developed incident NCD during follow-up; controls completed ≥10 years of follow-up and had normal cognition throughout follow-up period.

MEASUREMENTS

SCD was evaluated with a yes/no question based on "perceived decline in memory relative to previously attained abilities". The trajectories of SCD were modelled with mixed-effect logistic regression, using a backward timescale.

RESULTS

Those who developed NCD (cases) had new onset of SCD within past 20 years, which became particularly noticeable 13-14 years before diagnosis, and became even more evident in the last 4 years. Those who did not develop NCD (controls) reported SCD since younger age, with the probability of SCD remaining constant over time. The distinctive trajectories were consistent across Alzheimer's and non-Alzheimer's disease, and among those with higher baseline rates of SCD due to psychiatric conditions.

CONCLUSIONS

SCD exhibits distinctive trajectories among those who do and do not progress to NCD. These distinctive trajectories can inform NCD risk for early interventions, and guide public health messaging to distinguish high-risk SCD from normal ageing. Future SCD scales may possibly need to evaluate symptom changes over a longer, 20-year horizon to better capture the new onset of SCD within this longer timeframe.

An Autopsy Case of Amyotrophic Lateral Sclerosis With Sudden Death Showed Histological Features of Lewy Body Disease

We present the case of an 81-year-old man diagnosed with probable amyotrophic lateral sclerosis (ALS) based on the Updated Awaji criteria. The patient exhibited progressive motor neuron degeneration with muscle weakness, atrophy, and fasciculations primarily in the right lower limb and later extending to the right upper limb. Three months after being referred to a home care clinic, he collapsed in front of his family members and died. An autopsy revealed phosphorylated TDP-43 pathology consistent with ALS, with involvement of the hypoglossal nucleus, facial nerve nucleus, and medulla oblongata. Interestingly, widespread a-synuclein pathology indicative of diffuse neocortical type Lewy body disease (LBD; Braak stage 6) was identified, despite the absence of clinical parkinsonism or dementia with Lewy bodies (DLB) during his lifetime. The presence of autonomic symptoms such as constipation and urinary retention shortly before death may be attributable to a-synuclein pathology affecting the autonomic nervous system. The coexistence of ALS and LBD underscores the clinical challenge of diagnosing overlapping pathologies, as motor symptoms may obscure signs of LBD. Dopamine transporter imaging or MIBG myocardial scintigraphy might aid in identifying preclinical LBD in ALS patients with atypical symptoms. The patient died of respiratory failure due to extensive organizing pneumonia, but the possibility of sudden cardiac arrest could not be excluded. This case highlights the potential for coexisting neurodegenerative pathologies in ALS, emphasizing the importance of comprehensive evaluation when autonomic symptoms or other atypical features are present.

Efficacy and impact of spousal support groups in enhancing the well-being of caring in early onset dementia: Lessons learned from the ACE Alzheimer center Barcelona

Background: The group intervention aimed at caregivers of persons with dementia is regarded as an effective tool for support and education. However, these groups do not specifically cater to caregivers of individuals with spouses affected by young-onset dementia. Objective: To assess the effectiveness of a support and training group specifically targeted towards spouses of individuals with young onset dementia and its impact on reducing caregiver burden. Participants and Methods: Participants were recruited from a single memory clinic in Catalonia, Spain. The Zarit Burden Interview (ZBI) was utilized to evaluate caregiver burden both before and after participation in the support groups and a combined quantitative and qualitative analysis approach was employed. Results: A total of 77 caregivers were included and assessed, comprising 45.5% females with a mean age of 55 years and 54.5% males with a mean age of 63 years. While the overall caregiver burden, as measured by the ZBI, did not exhibit a significant reduction following participation in the group sessions, a notable decrease in ZBI scores was observed among caregivers with the highest burden at baseline. Three key stages were identified throughout the sessions: (1) discussions pertaining to the type of dementia and its associated changes; (2) the provision of care and attention to spouses along with the exchange of information among participants; and (3) identification of caregivers' needs. Conclusions: The subgroup of caregivers of persons with young onset dementia who exhibited the highest burden at baseline derived the greatest benefit from the support groups. Various qualitative indicators.

Reliability and modeling of digital histological measurements in Alzheimer's disease neuropathologic change and Lewy body disease

Digital histology offers a more objective, continuous definition of neuropathological severity than traditional staging systems, but its reliability remains underexplored. We calculated regional percentage areas occupied by phosphorylated tau (p-Tau, AT8), amyloid-β (Aβ, NAB228), and phosphorylated α-synuclein (p-αSyn, 81A) pathology in 24 autopsied cases with varying degrees of Alzheimer disease neuropathological change and Lewy body disease (LBD) using manual and automated immunostaining methods to investigate variability across protocols. We then compared natural log-transformed percent area occupied values (ln%AO) to blinded ordinal severity scores, Braak stages, Thal phases, and McKeith LBD stages. p-Tau ln%AO from methodologically similar runs had the highest correlations (R2 = 0.91-0.95, β  =  0.95-0.97 for manual and automated methods, respectively); p-αSyn ln%AO from disparate immunostaining methods had the lowest (R2 = 0.16-0.34 β  =  0.40-0.59). p-Tau and Aβ ln%AO increased regionally with higher Braak and Thal stages (p-Tau: z = 2.06 P = .04. Aβ: z = 3.70 P < .001). Regional p-αSyn ln%AO increased from limbic to neocortical stages (z = 5.86 P < .001); amygdala-predominant type LBD cases peaked in the amygdala and dropped in other limbic regions. These findings show the potential to quantify differences in p-Tau, Aβ, and p-αSyn pathologies using digital histological methods in single-center studies.

Predicting Phenoconversion in Isolated RBD: Machine Learning and Explainable AI Approach

Isolated rapid eye movement (REM) sleep behavior disorder (iRBD) is recognized as a precursor to neurodegenerative diseases. This study aimed to develop predictive models for the timing and subtype of phenoconversion in iRBD. We analyzed comprehensive clinical data from 178 individuals with iRBD over a median follow-up of 3.6 years and applied machine learning models to predict when phenoconversion would occur and whether progression would present with motor- or cognition-first symptoms. During follow-up, 30 patients developed a neurodegenerative disorder, and the extreme gradient boosting survival embeddings-Kaplan neighbors (XGBSE-KN) model demonstrated the best performance for timing (concordance index: 0.823; integrated Brier score: 0.123). Age, antidepressant use, and Movement Disorder Society-Unified Parkinson's Disease Rating Scale Part III scores correlated with higher phenoconversion risk, while coffee consumption was protective. For subtype classification, the RandomForestClassifier achieved the highest performance (Matthews correlation coefficient: 0.697), indicating that higher Montreal Cognitive Assessment scores and younger age predicted motor-first progression, whereas longer total sleep time was associated with cognition-first outcomes. These findings highlight the utility of machine learning in guiding prognosis and tailored interventions for iRBD. Future research should include additional biomarkers, extend follow-up, and validate these models in external cohorts to ensure generalizability.

Platelet miRNAs as early biomarkers for progression of idiopathic REM sleep behavior disorder to a synucleinopathy

Individuals diagnosed with isolated REM sleep behavior disorder (IRBD) have a high risk of developing Lewy body disorders (LBD), mainly Parkinson's disease (PD) or dementia with Lewy bodies (DLB). As we have previously identified seven platelet-derived miRNAs as potential biomarkers for DLB, in this pilot study we aimed to investigate whether specific expression changes of these miRNAs are also present in IRBD. RNA was obtained from platelets of individuals with IRBD (n = 29) and controls (n = 34), and miRNA levels were determined with a miRCURY LNA miRNA Custom PCR Panel. miRNA interactomes of deregulated miRNAs were determined, and mRNA quantification of miRNA target genes was carried out using real-time PCR and the ΔΔCt method. We found that the expression of hsa-miR- 139 - 5p (p = 0.010) and hsa-miR- 142 - 3p (p = 0.017) was diminished, while hsa-miR- 191 - 5p (p = 0.023) was increased in platelets of IRBD patients compared with controls. Interactome analysis of these miRNAs showed that hsa-miR- 142 - 3p regulates genes related to the structure and maintenance of the cytoskeleton. Of the 15 genes expressed in platelets, the expression of WASL, a gene involved in actin filament organization, was increased in platelets of IRBD patients. Additionally, WASL expression correlated inversely with hsa-miR- 142 - 3p expression. Since the interactomes of hsa-miR- 139 - 5p and hsa-miR- 191 - 5p play a role in several cancer types, their expression was not addressed. Changes in hsa-miR- 142 - 3p, hsa-miR- 139 - 5p, and hsa-miR- 191 - 5p expression were found in IRBD platelets and might represent early biomarkers for LBD involving cytoskeleton dysfunction. Increased expression of WASL could indicate that altered platelet activation occurs early during the development of LBD.

Cerebrospinal fluid and blood neurofilament light chain in Parkinson's disease and atypical parkinsonian syndromes: a systematic review and Bayesian network meta-analysis

BACKGROUND AND OBJECTIVE

The value of neurofilament light chain (NfL) levels as a biomarker for the diagnosis and differential diagnosis in patients with Parkinson's disease (PD) and atypical parkinsonian syndromes (APS) remains controversial. Furthermore, few studies have directly compared NfL levels among specific APS categories. This study aimed to compare cerebrospinal fluid (CSF) and blood NfL levels among PD, APS, other PD-related disorders, and controls, as well as rank NfL levels across these groups.

METHODS

PubMed, Embase, Web of Science, and the Cochrane Library were searched from the inception up to November 1st, 2024, to identify eligible studies reporting CSF or blood NfL concentrations in PD, PD dementia (PDD), multiple system atrophy (MSA), progressive supranuclear palsy (PSP), dementia with Lewy bodies (DLB), corticobasal syndrome (CBS), vascular parkinsonism (VP), essential tremor (ET), idiopathic rapid eye movement sleep behavior disorder (iRBD), and controls. The Bayesian approach was utilized to estimate the standardized mean difference (SMD) and the associated 95% credible intervals (CrIs) of NfL levels. The surface under the cumulative ranking curve (SUCRA) was employed to evaluate the ranking probabilities of NfL levels. Subgroup analysis and meta-regression were conducted to explore the sources of heterogeneity.

RESULTS

The present network meta-analysis (NMA) included 78 studies with 13,120 participants (4050 controls, 5021 PD, 191 PDD, 1173 MSA, 887 PSP, 1254 DLB, 319 CBS, 160 ET, 65 iRBD, and 0 VP). Of these, the NMA of CSF NfL included 34 studies with 6,013 participants, while the NMA of blood NfL included 49 studies with 7,787 participants. Both CSF and blood NfL levels were significantly elevated in patients with PD and APS compared to controls. Compared to PD patients, CSF NfL levels were significantly elevated in MSA (SMD 1.85; 95% CrI 1.55-2.15), CBS (1.42; 1.08-1.75), PSP (1.35; 1.06-1.64), and DLB 0.52; 0.20-0.85) patients. Similarly, blood NfL levels were significantly higher in patients with MSA (1.36; 1.02-1.71), PDD (1.19; 0.65-1.72), PSP (1.15; 0.77-1.54), CBS (0.92; 0.11-1.72), and DLB (0.63; 0.14-1.12) compared to PD. Among APS, CSF NfL levels in MSA patients were significantly higher than those in PSP, DLB, and CBS patients, while blood NfL levels in MSA patients were significantly higher only compared to DLB. In both CSF and blood NfL, MSA patients exhibited the highest probability of ranking first for NfL level elevations (CSF: SUCRA = 0.998; blood: SUCRA = 0.925). Age significantly influenced the SMD of the comparison between MSA and PD in CSF NfL (β = -0.15; p = 0.016).

CONCLUSIONS

CSF and blood NfL levels in PD and APS are higher than those in controls, and all APS categories show higher levels than PD, suggesting that NfL levels may serve as a potential biomarker for the differential diagnosis between PD and APS. However, caution is warranted when using NfL as a diagnostic biomarker for PD. Significant differences in NfL levels are also observed between certain APS categories. Patients with MSA exhibit the highest NfL levels among PD and related disorders.

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.

Pathological Characterisation of Posterior Cortical Atrophy in Comparison With Amnestic Alzheimer's Disease

AIMS

Posterior cortical atrophy (PCA) is a predominantly young-onset neurodegenerative syndrome, typically caused by Alzheimer's disease (PCA-AD). PCA-AD presents with visual and spatial dysfunction attributed to occipito-parietal or 'posterior' brain regions rather than memory difficulties characteristic of typical amnestic-led Alzheimer's disease (a-AD) attributed to medial temporal regions. Imaging and neuropathological studies suggest that PCA-AD is associated with a more posterior distribution of tau neurofibrillary tangles (NFTs), whereas β-amyloid pathology (Aβ) is diffusely deposited throughout the cortex. This study characterised the neuropathological substrates of PCA-AD in comparison with a-AD, to further understanding of the biological basis of phenotypical heterogeneity in AD.

METHODS

Immunohistochemistry for Aβ; tau; the microglial markers CD68, CR3-43 and Iba1; α-synuclein; and TDP-43 was carried out on 26 PCA-AD and 27 age and gender-matched a-AD cases at the Queen Square Brain Bank. Aβ, tau and the three microglial markers were quantified in the superior frontal, superior temporal, superior parietal and occipital (primary visual cortex) cortices, with α-synuclein and TDP-43 assessed using formal staging criteria. In addition, microglial circularity, a morphological indicator of microglial activation state, was calculated.

RESULTS

There was a higher load of Aβ and tau in the parietal region of PCA-AD compared to a-AD. In the PCA-AD compared to the a-AD group, there were significant increases in tau load in parietal and frontal relative to temporal regions. There was no difference in cerebral amyloid angiopathy (CAA) severity between PCA-AD and a-AD. There was a significantly lower temporal CD68 load in a-AD compared with PCA-AD. In a-AD, CD68 load was lowest and tau load highest in the temporal relative to all other regions.

CONCLUSIONS

This study demonstrates differences in the distribution of Aβ and tau and variations in regional neuroinflammatory response in PCA-AD and a-AD. These findings extend our understanding of the biological substrates underpinning PCA-AD and highlight the potential for exploring phenotypic variants to understand selective vulnerability in neurodegenerative diseases.

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.

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.

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.

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.

Prevalence, incidence and modifiable factors for subtypes of mild cognitive impairment: results from the Longitudinal Ageing Study in China

Background

As the population in China rapidly ages, the prevalence of mild cognitive impairment (MCI) is increasing considerably. However, the causes of MCI vary. The continued lack of understanding of the various subtypes of MCI impedes the implementation of effective measures to reduce the risk of advancing to more severe cognitive diseases.

Aims

To estimate the prevalence and incidence rates of two MCI subtypes-amnestic MCI (aMCI) and vascular cognitive impairment without dementia (VCIND)-and to determine modifiable factors for them among older individuals in a multiregional Chinese cohort.

Method

This 1-year longitudinal study surveyed a random sample of participants aged≥60 years from a large, community-dwelling cohort in China. Baseline lifestyle data were self-reported, while vascular and comorbid conditions were obtained from medical records and physical examinations. In total, 3514 and 2051 individuals completed the baseline and 1-year follow-up assessments, respectively. Logistic and linear regression analyses were used to identify the modifiable factors for MCI subtypes and predictors of cognitive decline, respectively.

Results

Among our participants, aMCI and VCIND demonstrated prevalence of 14.83% and 2.71%, respectively, and annual incidence (per 1000 person-years) of 69.6 and 10.6, respectively. The risk factor for aMCI was age, whereas its protective factors were high education level, tea consumption and physical activity. Moreover, VCIND risk factors were age, hypertension and depression. The presence of endocrine disease, cerebral trauma or hypertension was associated with a faster decline in cognition over 1 year.

Conclusions

MCI is a serious health problem in China that will only worsen as the population ages if no widespread interventions are implemented. Preventive strategies that promote brain activity and support healthy lifestyle choices are required. We identified modifiable factors for MCI in older individuals. The easy-to-adopt solutions such as tea consumption and physical activity can aid in preventing MCI.

Trial registration number

NCT03672448.

Alterations in non-REM sleep and EEG spectra precede REM-sleep deficits in a model of synucleinopathy

BackgroundSleep disturbances often precede motor symptoms in neurodegenerative diseases like Parkinson's disease (PD) and dementia with Lewy bodies (DLB). Neuroinflammation is implicated in PD pathophysiology and may contribute to non-motor symptoms such as sleep disturbances. The Thy1-αSyn mouse model, overexpressing human alpha-synuclein (αSyn), mimics key aspects of PD and DLB, making it valuable for studying related sleep disturbances and neuroinflammatory changes.ObjectiveTo investigate early-stage alterations in sleep architecture, electroencephalographic (EEG) patterns, and neuroinflammation in Thy1-αSyn mice.MethodsWe used telemetric EEG/electromyography (EMG) with video surveillance to compare sleep patterns and EEG spectral power between 2.5- and 4.5-month-old male Thy1-αSyn transgenic mice and wild-type littermates. Neuroinflammation was assessed by examining microglial (Iba1) and astrocytic (GFAP) activation in key sleep-regulating brain regions.ResultsThy1-αSyn mice showed decreased resting wake time and increased non-REM sleep, with altered sleep bout frequency and length, indicating significant sleep architecture changes. Spectral analysis revealed a shift from higher to lower frequency bands, suggesting early neural circuitry disruptions due to αSyn overexpression. Significant microglial activation was observed at 3 months, with astrogliosis progressing by 5 months in key sleep-regulating regions, indicating that neuroinflammation may contribute to the observed sleep disturbances.ConclusionsEarly-stage Thy1-αSyn mice exhibit significant sleep architecture changes, EEG spectral shifts, and neuroinflammatory alterations. These findings suggest that neuroinflammation may play a role in the initial pathophysiological changes in PD and related synucleinopathies. Sleep, EEG, and neuroinflammatory changes could serve as early biomarkers for these diseases.

Current concepts and molecular pathology of neurodegenerative diseases

Neurodegenerative diseases are a pathologically, clinically and genetically diverse group of diseases characterised by selective dysfunction, loss of synaptic connectivity and neurodegeneration, ​and are associated with the deposition of misfolded proteins in neurons and/or glia. Molecular studies have highlighted the role of conformationally altered proteins in the pathogenesis of neurodegenerative diseases and have paved the way for developing disease-specific biomarkers that capture and differentiate the main type/s of protein abnormality responsible for neurodegenerative diseases, some of which are currently used in clinical practice. These proteins follow sequential patterns of anatomical involvement and disease spread in the brain and may also be detected in peripheral organs. Recent studies suggest that glia are likely to have an important role in pathological spread throughout the brain and even follow distinct progression patterns from neurons. In addition to morphological and molecular approaches to the classification of these disorders, a further new stratification level incorporates the structure of protein filaments detected by cryogenic electron microscopy. Rather than occurring in isolation, combined deposition of tau, amyloid-β, α-synuclein and TDP-43 are frequently observed in neurodegenerative diseases and in the ageing brain. These can be overlooked, and their clinicopathological relevance is difficult to interpret. This review provides an overview of disease pathogenesis and diagnostic implications, recent molecular and ultrastructural classification of neurodegenerative diseases, how to approach ageing-related and mixed pathologies, ​and the importance of the protein-based classification system for practising neuropathologists and clinicians. This review also informs general pathologists about the relevance of ongoing full body autopsy studies to understand the spectrum and pathogenesis of neurodegenerative diseases.

Electroencephalography can Ubiquitously Delineate the Brain Dysfunction of Neurodegenerative Dementia by Both Visual and Automatic Analysis Methods: A Preliminary Study

Introduction: The aim was to examine the differences in electroencephalography (EEG) findings by visual and automated quantitative analyses between Alzheimer's disease (AD) and dementia with Lewy bodies (DLB) and Parkinson's disease with dementia (PDD). Methods: EEG data of 20 patients with AD and 24 with DLB/PDD (12 DLB and 12 PDD) were retrospectively analyzed. Based on the awake EEG, the posterior dominant rhythm frequency and proportion of patients who showed intermittent focal and diffuse slow waves (IDS) were visually and automatically compared between the AD and DLB/PDD groups. Results: On visual analysis, patients with DLB/PDD showed a lower PDR frequency than patients with AD. In patients with PDR <8 Hz and occipital slow waves or patients with PDR <8 Hz and IDS, DLB/PDD was highly suspected (PPV 100%) and AD was unlikely (PPV 0%). On automatic analysis, the findings of the PDR were similar to those on visual analysis. Comparisons between visual and automatic analysis showed an overlap in the focal slow wave commonly detected by both methods in 10 of 44 patients, and concordant presence or absence of IDS in 29 of 43 patients. With respect to PDR <8 Hz and the combination of PDR <8 Hz and IDS, PPV and NPV in DLB/PDD and AD were not different between visual and automatic analysis. Conclusions: As the noninvasive, widely available clinical tool of low expense, visual analysis of EEG findings provided highly sufficient information to delineate different brain dysfunction in AD and DLB/PDD, and automatic EEG analysis could support visual analysis especially about PD.

Propagation of pathologic α-synuclein from kidney to brain may contribute to Parkinson's disease

The pathogenesis of Lewy body diseases (LBDs), including Parkinson's disease (PD), involves α-synuclein (α-Syn) aggregation that originates in peripheral organs and spreads to the brain. PD incidence is increased in individuals with chronic renal failure, but the underlying mechanisms remain unknown. Here we observed α-Syn deposits in the kidneys of patients with LBDs and in the kidney and central nervous system of individuals with end-stage renal disease without documented LBDs. In male mice, we found that the kidney removes α-Syn from the blood, which is reduced in renal failure, causing α-Syn deposition in the kidney and subsequent spread into the brain. Intrarenal injection of α-Syn fibrils induces the propagation of α-Syn pathology from the kidney to the brain, which is blocked by renal denervation. Deletion of α-Syn in blood cells alleviates pathology in α-Syn A53T transgenic mice. Thus, the kidney may act as an initiation site for pathogenic α-Syn spread, and compromised renal function may contribute to the onset of LBDs.

Louis EK, Knopman DS, Graff-Radford NR, Day GS, Ferman TJ, Kremers WK, Petersen RC, Boeve BF, Lowe VJ, Kantarci K. Longitudinal FDG-PET Metabolic Change Along the Lewy Body Continuum

Importance

Although 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) is a well-established cross-sectional biomarker of brain metabolism in dementia with Lewy bodies (DLB), the longitudinal change in FDG-PET has not been characterized.

Objective

To investigate longitudinal FDG-PET in prodromal DLB and DLB, including a subsample with autopsy data, and report estimated sample sizes for a hypothetical clinical trial in DLB.

Design, Setting, and Participants

Longitudinal case-control study with mean (SD) follow-up of 3.8 (2.3) years. Cases were recruited consecutively between 2007 and 2022 at a referral center and among the population. Patients with probable DLB or mild cognitive impairment with Lewy bodies (MCI-LB) were included. Individuals without cognitive impairment were included from a population-based cohort balanced on age and sex for comparison. All participants completed at least 1 follow-up assessment by design.

Exposure

Patients with MCI-LB and DLB.

Main Outcomes and Measures

Rate of change in FDG-PET was assessed as standardized uptake value ratios (SUVr). Clinical progression was assessed with the Clinical Dementia Rating Sum of Boxes (CDR-SB) score.

Results

Thirty-five patients with probable DLB, 37 patients with MCI-LB, and 100 individuals without cognitive impairment were included. The mean (SD) age of the DLB and MCI-LB groups combined (n = 72) was 69.6 (8.2) years; 66 patients (92%) were men and 6 (8%) were women. At follow-up, 18 participants (49%) with MCI-LB had progressed to probable DLB. Patients with MCI-LB had a faster decline in FDG-SUVr, compared with that of participants without cognitive impairment, in the posterior cingulate, occipital, parietal, temporal, and lateral frontal cortices. The same regions showed greater metabolic decline in patients with DLB than in participants without cognitive impairment, with the addition of anterior-middle cingulate, insula, and medial frontal orbital cortices. Rates of change in FDG-PET in these brain regions were combined into a region of interest (ROI) labeled longitudinal FDG-PET LB meta-ROI. The rate of change in FDG-SUVr in the meta-ROI correlated with the rate of change in CDR-SB, and sample size estimates were reported for potential clinical trials in DLB. Findings were confirmed in the subsample with neuropathologic confirmation (n = 20).

Conclusions and Relevance

This study found that brain hypometabolism begins to evolve during the prodromal stages of DLB with changes paralleling symptomatic progression. These data may inform clinical practice and trials planning to use FDG-PET for biologic staging, monitoring disease progression, and potentially assessing treatment response.

Evaluation of cerebrospinal fluid levels of VAMP-2 and SNAP-25 in a dementia with Lewy bodies clinical cohort stratified by Alzheimer's pathophysiological biomarkers

BACKGROUND

Synaptic protein levels in cerebrospinal fluid (CSF) may represent much-needed objective biomarkers of cognitive impairment, disease progression and drug efficacy in patients with dementia with Lewy bodies (DLB). Soluble N-ethylmaleimide-sensitive factor attachment proteins receptors (SNARE) proteins, such as VAMP-2 and SNAP-25, are implicated in α-synuclein pathophysiology and CSF levels of these proteins are associated with pathophysiological biomarkers and cognitive decline in Alzheimer's disease (AD). The aim of the study was to compare CSF levels of VAMP-2 and SNAP-25 in patients with DLB to cognitively unimpaired controls and AD patients and study their association with cognitive performance and AD and neurodegeneration biomarkers.

METHODS

VAMP-2 and SNAP-25 were quantified in CSF from cognitively normal controls (n = 62), DLB (n = 44) and AD (n = 114) patients from the Sant Pau Initiative for Neurodegeneration (SPIN) cohort using homebrew Single Molecule Array assays (Simoa). The DLB group was stratified into two groups with ("DLB + AD", n = 28) or without AD co-pathology ("pure DLB", n = 16) using our validated cut-off for the CSF phosphorylated tau (p-tau)/Aβ42 ratio. We used linear regression to test for group differences (adjusting for age) and association with AD biomarkers. We used standardized w-scores of the cognitive tests to analyze the association of the synaptic markers with cognitive performance.

RESULTS

CSF VAMP-2 and SNAP-25 levels correlated across all groups (r = 0.71-0.9, p < 0.001). Both proteins were decreased in pure DLB (p < 0.001, p = 0.01) but increased in DLB + AD (p = 0.01, p = 0.02) compared to controls and showed good accuracy to discriminate pure DLB from DLB + AD (AUC = 0.84, 0.85). Both proteins were associated with CSF p-tau and total tau (t-tau) across all groups (r2 = 0.49-0.88, p < 0.001), with the Aβ42/40 ratio in DLB + AD (r2 = 0.29-0.36, p < 0.001) and in AD (r2 = 0.12-0.23, p < 0.001) and with CSF neurofilament-light chain (NfL) in controls (r²=0.10-0.11, p < 0.001-0.01) and AD patients (r²=0.01-0.08, p = 0.01 - 0.001). SNAP-25 was associated with CSF NfL in the DLB + AD group (r²=0.15, p = 0.02). CSF VAMP-2 and SNAP-25 were associated with phonemic fluency in pure DLB (r2 = 0.39 - 0.28, p = 0.01-0.03) and SNAP-25 with the Clock drawing test and the MMSE in DLB + AD (adj.r2 = 0.15 - 0.14, p = 0.03-0.03) and DLB (adj.r2 = 0.12 - 0.08, p = 0.02-0.04) groups.

CONCLUSIONS

CSF VAMP-2 and SNAP-25 are promising surrogate markers of synapse degeneration in DLB. However, care should be taken when interpreting CSF levels of these synaptic markers in DLB in light of the confounding effect of AD pathophysiological markers.

Unraveling the clinical-pathological correlations of subjects with isolated and mixed neurodegenerative processes in the National Alzheimer's Coordinating Center dataset

Although Alzheimer disease neuropathologic change (ADNC) is the most common pathology underlying clinical dementia, the presence of multiple comorbid neuropathologies is increasingly being recognized as a major contributor to the worldwide dementia burden. We analyzed 1051 subjects with specific combinations of isolated and mixed pathologies and conducted multivariate logistic regression analysis on a cohort of 4624 cases with mixed pathologies to systematically explore the independent cognitive contributions of each pathology. Alzheimer disease neuropathologic change and limbic-predominant age-related TDP-43 encephalopathy neuropathologic change (LATE-NC) were both associated with a primary clinical diagnosis of Alzheimer disease (AD) and were characterized by an amnestic dementia phenotype, while only ADNC associated with logopenic variant primary progressive aphasia (PPA). In subjects with ADNC and comorbid LATE-NC, Lewy body disease, and/or cerebrovascular disease, the clinical phenotype was usually diagnosed during life as "Probable AD." Conversely, the combination of ADNC with frontotemporal lobar degeneration with TDP-43, progressive supranuclear palsy (PSP), or corticobasal degeneration (CBD) resulted in a mixed clinical picture, with variable features of amnestic dementia, PPA subtypes, behavioral variant FTD, PSP syndrome, and CBD syndrome. These findings elucidate the cumulative effects of mixed pathologies and provide insights into interactions between neurodegenerative pathologies contributing to a variety of clinical dementia presentations.

The role of Apolipoprotein E4 on cognitive impairment in Parkinson's disease and Parkinsonisms

Cognitive impairment is a prevalent non-motor symptom of Parkinson's disease (PD), increasing the risk of dementia as the disease progresses. Despite its clinical significance, the etiology of cognitive impairment in PD remains unclear. Apolipoprotein E4 (APOE4), a well-known genetic risk factor of Alzheimer's disease, has been studied for its potential role in PD-related cognitive impairment. However, findings have been conflicting and thus inconclusive, highlighting a need to critically evaluate the current research. Several studies using neuroimaging modalities have explored the brains of individuals with PD and atypical parkinsonian disorders who have APOE4. Some of these studies have identified distinct neuropathological changes that have been previously reported to be associated with cognitive impairments in those with Parkinsonisms. Here, we review the role of APOE4 on cognitive impairment in PD and atypical Parkinsonisms using neuroimaging evidence. We will examine how APOE4 may contribute to pathological changes within the brain and its association with cognitive impairment.

Histopathological Investigation of Progressive Encephalomyelitis with Rigidity and Myoclonus: An Autopsy Case Characterized by Oculomotor Dysfunction and Autonomic Failure

Progressive encephalomyelitis with rigidity and myoclonus (PERM) is a rare disease associated with the presence of anti-glycine receptor (GlyR) antibodies. We herein report an autopsy case of an 80-year-old man diagnosed with anti-GlyR antibody-positive PERM who presented with symptoms of oculomotor dysfunction and autonomic failure. Despite intensive immunotherapy, the neurological symptoms showed almost no improvement, and the patient succumbed to aspiration pneumonia and bacterial translocation. Postmortem pathology revealed mild inflammatory changes and neuronal loss that were disproportionate to a severe clinical presentation. These results suggest that the clinical symptoms of PERM may result from antibody-mediated GlyR internalization, leading to neuronal disinhibition, rather than a neuroinflammatory signature.

The potential of circulating nonesterified fatty acids and sphingolipids in the biological understanding of cognitive decline and dementia

PURPOSE OF REVIEW

Cognitive decline and late-onset dementia pose significant challenges in aging societies, and many dementia cases could be prevented or delayed through modification of associated risk factors, many of which are tied to cardiovascular and metabolic dysfunction. As individuals age, the blood-brain barrier becomes more permeable, easing the exchange of molecules between the bloodstream and the brain. Consequently, blood-based biological markers (so-called biomarkers) provide a minimally invasive and accessible means of accessing molecular changes associated with aging and neurodegeneration.

RECENT FINDINGS

Circulating free fatty acids, also called nonesterified fatty acids (NEFAs), and sphingolipids are associated with cardiovascular disease, insulin resistance, and diabetes; thus, could be promising candidates as biomarkers for cognitive decline and dementia.

SUMMARY

The opportunity to study such minimally invasive biomarkers further opens up potential new avenues for improved understanding of the underlying biology of diseases of the brain.

The effect of Amyloid and Tau Co-pathology on disease progression in Lewy body dementia: A systematic review

Co-morbid Alzheimer's disease (AD) pathology (amyloid-beta and tau) is commonly observed in Lewy body dementia (LBD), and this may affect clinical outcomes. A systematic review of the effect of AD co-pathology on longitudinal clinical outcomes in LBD was conducted. A search of MEDLINE and EMBASE (October 2024) yielded n = 3558 records that were screened by two independent reviewers. Included studies (n = 31) assessed AD co-pathology in LBD by neuropathologic examination (n = 10), positron emission tomography (PET) imaging (n = 7), cerebrospinal fluid (CSF) (n = 8) or plasma biomarkers (n = 6); and reported longitudinal clinical outcomes including cognitive and functional decline, mortality, or treatment response. Most neuropathology, PET and plasma studies reviewed demonstrated poorer prognosis in LBD + compared to LBD-, but discrepant findings were seen among CSF studies. No included study reported better outcomes in LBD+. The risk of bias was assessed with the Quality in Prognosis Studies tool. All studies rated as low risk of bias (n = 12) reported that the presence of AD co-pathology in LBD (LBD+) was associated with accelerated cognitive decline (n = 7/7), accelerated functional decline (n = 3/3), greater mortality (n = 2/2) and poorer response to treatment (n = 1/1). Among these studies, LBD+ was associated with an additional decline of -0.53 to -2.9 MMSE points/year compared to LBD-, while one study reported an adjusted hazard ratio for mortality in LBD + as 3.70. We conclude that AD co-pathology is associated with worse clinical outcomes in LBD whether assessed by greater cognitive decline, increased mortality or greater decline on functional assessment scales.

Neuropsychological test performance in mild cognitive impairment with Lewy bodies: A systematic review and meta-analysis

BACKGROUND

We sought to characterize the cognitive profile among individuals with mild cognitive impairment with Lewy bodies (MCI-LB) to help guide future clinical criteria.

METHODS

Systematic review and meta-analysis included MCI-LB studies with cognitive data from PubMed, Embase, Web of Science, and PsycINFO (January 1990 to March 2023). MCI-LB scores were compared to controls, MCI due to Alzheimer's disease (MCI-AD), and dementia with Lewy bodies (DLB) groups with random-effects models.

RESULTS

We included 26 studies and 2823 participants. Across all domains, the MCI-LB group performed worse than controls and better than DLB. Compared to MCI-AD, the MCI-LB group performed worse in attention/processing speed (g = -0.24, 95% confidence interval [CI]: -0.35, -0.12), attention/executive (g = -0.42, 95% CI: -0.56, -0.28); better in verbal immediate recall (g = 0.37; 95% CI: 0.15, 0.59) and delayed memory (g = 0.40; 95% CI: 0.22, 0.58).

DISCUSSION

The cognitive profiles in MCI-LB and MCI-AD are consistent with established profiles in DLB and AD. Neuropsychological assessment may be helpful in differential diagnosis, even in early disease states.

HIGHLIGHTS

We performed a systematic review and meta-analysis for cognition in mild cognitive impairment with Lewy bodies (MCI-LB). Compared to MCI due to Alzheimer's disease (MCI-AD), MCI-LB had worse attention, executive function, and processing speed. Compared to MCI-AD, MCI-LB had better verbal immediate and delayed recall. The MCI-LB group was worse on all cognitive domains than controls, and better than dementia with Lewy bodies. Studies used different tests and there is a need for global efforts for harmonization.

Characterization of cognitive decline in long-duration type 1 diabetes by cognitive, neuroimaging, and pathological examinations

BACKGROUNDWe aimed to characterize factors associated with the under-studied complication of cognitive decline in aging people with long-duration type 1 diabetes (T1D).METHODSJoslin "Medalists" (n = 222; T1D ≥ 50 years) underwent cognitive testing. Medalists (n = 52) and age-matched nondiabetic controls (n = 20) underwent neuro- and retinal imaging. Brain pathology (n = 26) was examined. Relationships among clinical, cognitive, and neuroimaging parameters were evaluated.RESULTSCompared with controls, Medalists had worse psychomotor function and recall, which associated with female sex, lower visual acuity, reduced physical activity, longer diabetes duration, and higher inflammatory cytokines. On neuroimaging, compared with controls, Medalists had significantly lower total and regional brain volumes, equivalent to 9 years of accelerated aging, but small vessel disease markers did not differ. Reduced brain volumes associated with female sex, reduced psychomotor function, worse visual acuity, longer diabetes duration, and higher inflammation, but not with glycemic control. Worse cognitive function, lower brain volumes, and diabetic retinopathy correlated with thinning of the outer retinal nuclear layer. Worse baseline visual acuity associated with declining psychomotor function in longitudinal analysis. Brain volume mediated the association between visual acuity and psychomotor function by 57%. Brain pathologies showed decreased volumes, but predominantly mild vascular or Alzheimer's-related pathology.CONCLUSION To our knowledge, this is the first comprehensive study of cognitive function, neuroimaging, and pathology in aging T1D individuals demonstrated that cognitive decline was related to parenchymal rather than neurovascular abnormalities, unlike type 2 diabetes, suggestive of accelerated aging in T1D. Improving visual acuity could perhaps be an important preventive measure against cognitive decline in people with T1D.FUNDINGThe Beatson Foundation, NIH/NIDDK grants 3P30DK036836-34S1 and P30DK036836-37, and Mary Iacocca fellowships.

From Night to Light: A Bibliometric Analysis of the Global Research Trajectory of Sleep Disorders in Parkinson's Disease

Purpose

Sleep disorders are prevalent non-motor symptoms in patients with Parkinson's disease (PD), significantly diminishing the overall quality of life for patients and potentially accelerating the deterioration of motor and cognitive functions, accelerating disease progression. Despite increasing research on sleep disorders in PD, a comprehensive analysis of the knowledge structure and key issues in this field are still lacking. This study aims to identify research hotspots and emerging trends related to sleep disorders in PD through a detailed bibliometric analysis.

Patients and Methods

On October 1, 2024, an extensive search was conducted in the Web of Science Core Collection (WOSCC) database to gather relevant literature on sleep disorders in PD. Bibliometric and knowledge mapping analyses were performed using CiteSpace, VOSviewer, and bibliometrix.

Results

Between January 1, 2004, and October 1, 2024, a total of 3,655 publications on sleep disorders in PD were published by 3,387 institutions across 87 countries. The volume of publications has shown a steady increase, a trend projected to continue. Current research is primarily centered on Neurosciences, Pharmacology, and Clinical Neurology. Emerging trends involve comprehensive evaluations of sleep, early diagnosis and prevention of various sleep disorder subtypes in PD, and advancing research through animal models to develop effective therapies. Emerging keywords include machine learning, sleep quality, biomarkers, covid-19, and mouse model.

Conclusion

This bibliometric analysis sheds light on the global landscape of PD-related sleep disorder research over the past two decades, highlighting key countries, institutions, authors, and journals driving advancements in the field. Moreover, it uncovers pivotal research hotspots and emerging trends, offering valuable insights and guidance for scholars engaged in this area.

The Role of the Claustrum in Parkinson's Disease and Vascular Parkinsonism: A Matter of Network?

BACKGROUND

The mechanisms underlying extrapyramidal disorders and their anatomical substrate have been extensively investigated. Recently, the role of the claustrum in Parkinson's disease and other neurodegenerative conditions has been better detailed. The main aim of this review was to summarize the supporting evidence for the role of the claustrum in degenerative and vascular parkinsonism.

METHODS

The anatomy, biology, vascular supply, and connections of the claustrum in humans were identified and described, providing the substrate for the vascular involvement of the claustrum in large- and small-vessel disease. The vascular supply of the claustrum includes up to three different sources from a single artery, the middle cerebral artery, and it is known as territory with an intermediate hemodynamic risk. The connections of the claustrum make it a sensory integrator and a relevant point in several networks, from consciousness to movement planning.

CONCLUSIONS

The claustrum is still an incompletely explained structure. However, recent description of its multiple connections indicate that it is involved in several diseases, including Parkinson's disease. The evidence underlying its potential role in vascular parkinsonism is still scarce, but it might be a field warranting future investigations.

Early Motor Signs in Pathologically Verified Alzheimer's Disease and Lewy Body Disease

BACKGROUND

The neuropathologies of Alzheimer's disease (AD) and Lewy body disease (LBD) commonly co-occur. Parkinsonism is the hallmark feature in LBD but it can be difficult to predict the presence of these co-pathologies early in the course of clinical disease. Timely diagnosis has crucial implications, especially with the advent of disease-modifying therapies.

OBJECTIVES

We sought to define early motor features that predict the ultimate neuropathological diagnoses of normal, AD, AD with concurrent LB pathology, and pure LB.

METHODS

We examined the associations between individuals' early motor features from their initial visit using the Unified Parkinson's Disease Rating Scale (UPDRS) Part III and their neuropathological diagnoses using the U.S. National Alzheimer's Coordinating Center (NACC) Database.

RESULTS

We included data from participants with neuropathologically normal brains (n = 49), AD (n = 502), AD w/LB (n = 167), and pure LB (n = 51). Total UPDRS Part III scores were increasingly higher with purer LB pathology. Decreased facial expression at baseline differentiated those with AD w/LB pathology from those with AD. Participants having pure LB pathology more often had deficits in speech, facial expression, posture, gait, bradykinesia, and upper extremity rigidity relative to those with AD w/LB.

CONCLUSION

Diminished facial expression significantly predicted the presence of LBs among those with concurrent AD pathology. Worse early speech, facial expression, posture, gait, bradykinesia, and upper extremity rigidity were suggestive of more pure LB pathology. These findings emphasize the utility of the neurological exam in the clinical assessment of persons with cognitive complaints as it can guide management.

Exploring sex differences in Alzheimer's disease: a comprehensive analysis of a large patient cohort from a memory unit

BACKGROUND

Alzheimer's disease (AD) stands as the leading cause of dementia worldwide, and projections estimate over 150 million patients by 2050. AD prevalence is notably higher in women, nearly twice that of men, with discernible sex differences in certain risk factors. To enhance our understanding of how sex influences the characteristics of AD patients and its potential impact on the disease trajectory, we conducted a comprehensive analysis of demographic, clinical, cognitive, and genetic data from a sizable and well-characterized cohort of AD dementia patients at a memory clinic in Barcelona, Spain.

METHODS

The study cohort comprised individuals with probable and possible AD dementia with a Clinical Dementia Rating (CDR) score between 1 and 3 diagnosed at the Memory Unit from Ace Alzheimer Center Barcelona, Spain, between 2008 and 2018. We obtained cognitive baseline data and follow up scores for the Mini-Mental State Examination (MMSE), the CDR scale, and the neuropsychological battery used in our center (NBACE). We employed various statistical techniques to assess the impact of sex on cognitive evolution in these dementia patients, accounting for other sex-related risk factors identified through Machine Learning methods.

RESULTS

The study cohort comprised a total of 6108 individuals diagnosed with AD dementia during the study period (28.4% males and 71.6% females). MMSE scores exhibited an average decline of approximately two units per year, unaffected by sex. Similarly, the decline in most neuropsychological functions assessed by NBACE did not exhibit significant differences between males and females. However, we observed that women diagnosed with mild AD dementia progressed more rapidly based on their CDR score (HR = 2.57, 95%CI:2.33-2.84) than men (HR = 2.03, 95%CI: 1.71-2.41) (p-interaction = 0.01).

CONCLUSIONS

Our findings do not strongly support the notion that sex significantly modifies the clinical progression of AD dementia based on cognitive data. Further research is essential to validate whether women with mild AD dementia indeed progress more rapidly than men at a similar stage and to delve into the potential underlying reasons for this finding.

Perceptions and practices of imaging personnel and physicians regarding the use of brain MRI for dementia diagnosis in Uganda

INTRODUCTION

Diagnosing dementia remains challenging in low-income settings due to limited diagnostic options and the absence of definitive biomarkers. The use of brain MRI in the diagnosis of dementia is infrequent in Uganda, and even when it is used, subtle findings like mild regional atrophy are often overlooked, despite being crucial for imaging diagnosis.

OBJECTIVE

The purpose of this study was to explore the perceptions and practices of imaging personnel and physicians regarding the use of brain MRI as a diagnostic approach for dementia in Uganda.

METHODS

This was an exploratory qualitative study involving radiologists, technologists, senior house officers and psychiatrists. The participants were 25 in total. Data was collected through key informant interviews and focus group discussions and analyzed thematically using an inductive approach.

RESULTS

The study revealed three key themes: Brain MRI Practices for Diagnosing Dementia, Facilitators of Appropriate MRI Use, and Barriers to Appropriate Use of Brain MRI. Sub-themes under these themes included cost considerations, poor and good MRI practices, MRI as a standard operating procedure, positive attitudes towards brain MRI, and barriers such as structural, financial, operational, technical, and patient-related issues. Participants acknowledged the high accuracy and superiority of brain MRI for diagnosing dementia and recognized it as the standard of care. However, its use in Uganda is limited due to high costs, restricted access, mechanical failures, patient claustrophobia, myths and misconceptions, and interpretation difficulties by radiologists and inappropriate protocols by technologists.

CONCLUSION

The study identifies barriers to effective brain MRI use for dementia diagnosis in Uganda, including limited training, high costs, and uneven equipment distribution. Despite this, providers are positive about MRI adoption. Enhancing training, awareness, and phased rollouts can improve outcomes. Future research should focus on similar low-resource settings for validation.

Rural Roads to cognitive Resilience (RRR): A prospective cohort study protocol

BACKGROUND

Ambient air pollution, detrimental built and social environments, social isolation (SI), low socioeconomic status (SES), and rural (versus urban) residence have been associated with cognitive decline and risk of Alzheimer's disease and related dementias (ADRD). Research is needed to investigate the influence of ambient air pollution and built and social environments on SI and cognitive decline among rural, disadvantaged, ethnic minority communities. To address this gap, this cohort study will recruit an ethnoracially diverse, rural Florida sample in geographic proximity to seasonal agricultural burning. We will (1) examine contributions of smoke-related fine particulate matter (PM2.5) exposures to SI and cognitive function; (2) determine effects of built and social environments on SI and cognitive function; and (3) contextualize SI and cognitive function among residents from different ethnoracial groups during burn and non-burn seasons.

METHODS

We will recruit 1,087 community-dwelling, dementia-free, ≥45-year-olds from five communities in Florida's Lake Okeechobee region. Over 36 months, participants will complete baseline visits to collect demographics, health history, and health measurements (e.g., blood pressure, body mass index) and 6-month follow-ups assessing cognitive function and social isolation at each visit. A subsample of 120 participants representative of each community will wear smartwatches to collect sensor data (e.g., heart rate) and daily routine and predefined activities (e.g., GPS-captured travel, frequent destinations) over two months. Ecological momentary assessments (EMA) (e.g., whether smoke has bothered participant in last 30 minutes) will occur over two months during agricultural burning and non-burning months. PurpleAir monitors (36 total) will be installed in each community to continuously monitor outdoor PM2.5 levels.

DISCUSSION

We expect to identify individual- and community-level factors that increase the risk for SI and cognitive decline in a vulnerable rural population.

Factors associated with phenoconversion of idiopathic rapid eye movement sleep behavior disorder: a prospective study

This study explores the effect of risk factors on the progression of idiopathic rapid eye movement (REM) sleep behavior disorder (iRBD) to α-synucleinopathies in a Chinese cohort. Patients with iRBD were enrolled and assessed for environmental factors and lifestyle using standardized structured questionnaires at baseline. All patients were prospectively followed for phenoconversion monitoring. The cumulative incidence was estimated using survival analysis. Of 155 iRBD enrolled in the cohort, follow-up information was available in 141 patients. The phenoconversion rate was 16.3% after 3 years, 27.6% after 5 years, and 57.2% after 10 years. Eighteen participants converted within 3 years, 27 converted within 5 years, and 36 converted within 10 years. IRBD with positive family history of parkinsonism had an increased risk of being converted to α-synucleinopathies, while tea drinking was associated with a decreased phenoconversion risk. Our findings shed light on a potential application of tea drinking in modifying iRBD progression.

Plasma biomarkers of amyloid, tau, astrogliosis, and axonal injury in a mixed memory clinic cohort

INTRODUCTION

Studies have shown that blood biomarkers can differentiate dementia disorders. However, the diagnosis of dementia still relies primarily on cerebrospinal fluid and imaging modalities. The new disease-modifying treatments call for more widely applicable biomarkers.

METHODS

Plasma samples (n = 250) from two mixed memory clinic were included. Participants were divided into amyloid beta positives (Aβ+) and Aβ negatives (Aβ-). Plasma phosphorylated tau (p-tau) 181, p-tau231, Aβ1-42 (Aβ42), Aβ40, Aβ42/Aβ40, glial fibrillary acidic protein (GFAP), and neurofilament light chain (NfL) were measured by single molecule array.

RESULTS

Significant differences were found among cognitively unimpaired, mild cognitive impairment, Alzheimer's disease (AD), and non-AD, and nearly all of the biomarkers were able to predict amyloid status. When combining p-tau181 and p-tau231 they predicted Aβ positivity with an area under the curve (AUC) of 0.75, and when combining all biomarkers an AUC of 0.86 was found.

DISCUSSION

This study supports previous findings on plasma biomarkers, even when investigated in a typical clinical setting in a consecutive, heterogeneous, mixed memory clinic.

Highlights

This study investigated seven plasma biomarkers in a mixed memory clinic, regardless of amyloid co-pathology or atypical phenotypes.These findings support previous promising results on plasma biomarkers, even when investigated in a heterogeneous population.The combination of phosphorylated tau (p-tau)181 and p-231 performed only slightly worse than a panel of multiple biomarkers, aligning with previous studies.Plasma biomarkers show potential for future applications in primary care, treatment monitoring, and trial selection.

Caregiver perspectives enable accurate diagnosis of neurodegenerative disease

BACKGROUND

The history from a relative or caregiver is an important tool for differentiating neurodegenerative disease. We characterized patterns of caregiver questionnaire responses, at diagnosis and follow-up, on the Cambridge Behavioural Inventory (CBI).

METHODS

Data-driven multivariate analysis (n = 4952 questionnaires) was undertaken for participants (n = 2481) with Alzheimer's disease (typical/amnestic n = 543, language n = 50, and posterior cortical n = 50 presentations), Parkinson's disease (n = 740), dementia with Lewy bodies (n = 55), multiple system atrophy (n = 55), progressive supranuclear palsy (n = 422), corticobasal syndrome (n = 176), behavioral variant frontotemporal dementia (n = 218), semantic (n = 125) and non-fluent variant progressive aphasia (n = 88), and motor neuron disease (n = 12).

RESULTS

Item-level support vector machine learning gave high diagnostic accuracy between diseases (area under the curve mean 0.83), despite transdiagnostic changes in memory, behavior, and everyday function. There was progression in CBI subscores over time, which varied by diagnosis.

DISCUSSION

Our results highlight the differential diagnostic information for a wide range of neurodegenerative diseases contained in a simple, structured collateral history.

HIGHLIGHTS

We analyzed 4952 questionnaires from caregivers of 2481 participants with neurodegenerative disease. Behavioral and neuropsychiatric manifestations of neurodegenerative disease had overlapping diagnostic boundaries. Simple questionnaire response patterns were sufficient for accurate diagnosis of each disease. We reinforce the value of a collateral history to support a diagnosis of dementia. The Cambridge Behavioural Inventory is sensitive to change over time and suitable as an outcome measure in clinical trials.

Proteomic signatures of Alzheimer's disease and Lewy body dementias: A comparative analysis

INTRODUCTION

We aimed to identify unique proteomic signatures of Alzheimer's disease (AD), dementia with Lewy bodies (DLB), and Parkinson's disease dementia (PDD).

METHODS

We conducted a comparative proteomic analysis of 33 post mortem brains from AD, DLB, and PDD individuals without dementia focusing on prefrontal, cingulate, and parietal cortices, using weighted gene co-expression network analyses with differential enrichment analysis.

RESULTS

Network modules revealed hub proteins common to all dementias. Lewy body dementias differed from AD by reduced levels of the autophagy protein p62 (SQSTM1), whereas DLB was distinguished from both AD and PDD by altered TRIM33 and cysteine/glutamate transporter (SLC7A11) across brain regions. An increase in mitochondrial and synaptic proteins was related to better cognition whereas enrichment in the extracellular matrix, complement system, and autophagy proteins was associated with greater cognitive impairment.

DISCUSSION

Our study offers valuable insights into the network-based biomarker characterization of molecular signatures of AD, DLB, and PDD.

HIGHLIGHTS

Reduced levels of the autophagy protein p62 (SQSTM1) differentiated Lewy body dementias from Alzheimer's disease (AD) across multiple brain regions. Dementia with Lewy bodies (DLB) was distinguished from both AD and Parkinson's disease dementia (PDD) by altered TRIM33 and cysteine/glutamate transporter (SLC7A11) levels across brain regions. Key mitochondrial oxidative phosphorylation proteins (e.g., COX7A2, TOMM40L, NDUFV1), and synaptic proteins (e.g., GABRB3, GABRB2, GLUA3, GLUA4, SNAP47, dynamin1) were more abundant in preserved cognitive states. Extracellular matrix proteins and members of the complement system (decorin, biglycan, C4A, C4B) showed a strong positive correlation with cognitive decline.

Sick sinus syndrome and high-degree atrioventricular block in dementia with Lewy bodies and other dementia subtypes: A study of ≈ 73,000 patients with dementia

INTRODUCTION

Lewy body pathology is commonly found in cardiac nervous tissue, including the cardiac conduction system. This study aimed to investigate the occurrence of sick sinus syndrome (SSS) and high-degree atrioventricular block in dementia with Lewy bodies (DLB) compared to Alzheimer's disease (AD) and other dementia subtypes.

METHODS

We included 73,619 individuals diagnosed with dementia from the Swedish Dementia Registry. Data pertaining to incident pacemaker implantation was obtained from the Swedish Pacemaker Registry.

RESULTS

SSS was more common in the DLB compared to the AD cohort (2.2% vs. 1.5%, P = 0.008). In adjusted models, SSS was associated with DLB compared to AD (odds ratio, 1.49; 95% confidence interval: 1.11-2.01).

DISCUSSION

We showed that incident pacemaker implantation secondary to SSS was more common in patients with DLB compared to those with AD.

HIGHLIGHTS

Incident pacemaker implantation secondary to sick sinus syndrome (SSS; but not high-degree atrioventricular block [HAVB]) was more common in dementia with Lewy bodies (DLB) versus Alzheimer's disease (AD).In adjusted models, SSS (but not HAVB) was positively associated with DLB compared to AD.Pacemaker data of various dementia disorders are presented.

Neuropsychological and clinical indicators of Lewy body and Alzheimer's pathology

Background

Clinical distinction between Alzheimer's disease (AD) and dementia with Lewy bodies (DLB) poses significant challenges due to pathological comorbidity. Similar ages of onset and overlapping cognitive and psychiatric symptoms can lead to diagnostic inaccuracy and inappropriate treatment recommendations.

Objective

Identify the best combination of clinical and neuropsychological predictors of AD, DLB, and mixed DLB/AD neuropathology in dementia patients.

Methods

Using the National Alzheimer's Coordinating Center dataset, we selected either pure AD (n = 189), DLB (n = 21), or mixed DLB/AD (n = 42) patients on autopsy. Neuropsychological and clinical predictors, including core clinical features of DLB, were entered into multivariable logistic regressions.

Results

Gait disturbances (odds ratio (OR) = 19.32; p = 0.01), visual-spatial complaints (OR = 6.06; p = 0.03), and visual hallucinations (OR = 31.06; p = 0.002) predicted DLB compared to AD, along with better memory (OR = 3.42; p = 0.003), naming (OR = 3.35; p = 0.002), and worse processing speed (OR = 0.51; p = 0.01). When comparing DLB to DLB/AD, gait disturbances (OR = 6.33; p = 0.01), increased depressive symptoms (OR = 1.44; p = 0.03), and better memory (OR = 3.01; p = 0.004) predicted DLB. Finally, rapid eye movement sleep behavior disorder (RBD) (OR = 6.44; p = 0.004), parkinsonism severity (OR = 1.07; p = 0.02), and lower depressive symptoms (OR = 0.70; p = 0.006) and memory impairment (OR = 0.57; p = 0.02) distinguished DLB/AD from AD.

Conclusions

Our study converges with prior research suggesting specific neuropsychological and clinical features can help distinguish DLB from AD. Neuropsychological differentiation becomes more challenging among mixed pathologies and in advanced cognitive impairment, although the presence of RBD and parkinsonism distinguished DLB. Earlier clinical assessment and incorporation of in vivo and postmortem biomarkers should enhance diagnostic accuracy and understanding of disease characteristics, offering significant relevance for disease-modifying treatments.

Separating dementia with Lewy bodies from Alzheimer's disease dementia using a volumetric MRI classifier

OBJECTIVES

Distinguishing dementia with Lewy bodies (DLB) from Alzheimer's disease (AD) dementia, particularly in patients with DLB and concomitant AD pathology (DLB/AD+), can be challenging and there is no specific MRI signature for DLB. The aim of this study is to examine the additional value of MRI-based brain volumetry in separating patients with DLB (AD+/-) from patients with AD and controls.

METHODS

We included 1518 participants from four cohorts (ADC, ADNI, PDBP and PredictND); 147 were patients with DLB (n = 76, DLB/AD+; n = 71, DLB/AD-), 668 patients with AD dementia, and 703 controls. We used an automatic segmentation tool to compute volumes of 70 brain regions, for which age, sex, and head size-dependent z-scores were calculated. We compared individual regions between the diagnostic groups and evaluated whether combining multiple regions improves differentiation. To assess the diagnostic performance, we used the area under the receiver operating characteristic curve (AUC) and sensitivity.

RESULTS

The classifier using the combination of 70 volumetric brain regions correctly classified 60% of patients with DLB and 70% of patients with AD dementia. For DLB vs. AD, the classifier produced an AUC of 0.80 (0.77-0.83), which outperformed the best individual region, hippocampus (AUC: 0.73 [0.69-0.76], p < 0.01). For the comparison of DLB/AD+ vs. AD, the classifier increased the AUC to 0.74 (0.68-0.80), which was 0.70 (0.64-0.76) for the hippocampus, p = 0.25.

CONCLUSION

Using a combination of volumetric brain regions improved the classification accuracy, and thus the discrimination, of patients with DLB with and without concomitant AD pathology and AD.

KEY POINTS

Question No specific MRI signature for dementia with Lewy bodies (DLB) exists, making the differential diagnosis challenging, especially with dementia due to Alzheimer's disease (AD). Findings Volumes of individual brain regions defined by automatic MRI segmentation differed between DLB and AD patients and controls. Clinical relevance Automatic MRI segmentation can contribute to improving the discrimination of patients with DLB and AD, especially in non-specialized memory clinics.