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

Identifying reversible psychiatric dementia mimics in new memory clinic outpatients

Background

Timely identification of reversible conditions that mimic dementia is critical in memory clinic practice. However, psychiatric conditions as potential dementia mimics have not been studied as thoroughly as neurological ones, and detailed data on their reversibility remain limited.

Objective

To identify reversible psychiatric dementia mimics.

Methods

A retrospective chart review was conducted on 749 new outpatients to investigate etiologies, progression rates, a neuropsychological assessment, cognitive and functional levels, and potential reversibility, categorized by psychiatric and neurological conditions. Cases showing cognitive reversibility following treatment were also identified. Comparisons were made based on the presence or absence of potential reversibility, as well as actual reversibility.

Results

Among the 749 individuals, 121 (16.2%) had potentially reversible conditions: 75 psychiatric and 46 neurological. Psychiatric conditions included depression, schizophrenia and delusional disorders, developmental disorders, alcohol use disorder, and dissociative and anxiety disorders. Compared to individuals without potentially reversible conditions, individuals with psychiatric conditions were younger, had a faster progression rate, and demonstrated higher cognitive function. Of the individuals who had mild cognitive impairment or dementia mimic, 6 (0.9%) showed complete cognitive resolution (3 cases) or partial cognitive improvement (3 cases). These 6 cases included two individuals with psychiatric conditions manifesting psychotic features.

Conclusions

While rare, reversible psychiatric dementia mimics highlight the importance of comprehensive evaluations in memory clinics, particularly for younger individuals experiencing rapid cognitive decline. The infrequency of reversibility may reflect a strong association between these potentially reversible conditions and dementia risk factors, or their role as prodromes of dementia itself.

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.

The relationship between age and physical activity as objectively measured by accelerometers in older adults with and without dementia

Objective

This study sought to investigate differences in physical activity and activity fragmentation between older adults with and without dementia and between older adults with dementia with Lewy bodies (DLB) and older adults with Alzheimer's disease (AD). The study also sought to investigate how these differences vary in magnitude at different ages.

Methods

Accelerometry data were analyzed from individuals with dementia (n = 94) and individuals without dementia (n = 613) who participated in the National Health and Aging Trends Study (NHATS), as well as from individuals with DLB (n = 12) and AD (n = 10) who participated in a pilot study.

Results

In the NHATS cohort, individuals without dementia had more activity counts (0.325 million [95% CI 0.162 million, 0.487 million]) and a longer active bout length (0.631 minutes [95% CI 0.311, 0.952]) at the mean age of 79 than individuals with dementia at the same age. There was also suggestive evidence that individuals without dementia had a shorter resting bout length (-2.196 minutes [95% CI -4.996, 0.605]) than individuals with dementia. Differences in data collection and processing prevented direct comparisons between the cohorts, and the parallel analyses in the smaller cohort were underpowered to detect statistically significant differences between DLB and AD.

Conclusion

This work shows that objectively measured accelerometry data differ between individuals with and without dementia; future studies with larger samples should investigate whether accelerometry data can be used to aid in the early identification of dementia and differentiation of dementia subtypes.

CD4+ T-cell transcription factors predict phenoconversion in idiopathic rapid eye movement sleep behavior disorder

Aim: Early biomarkers of phenoconversion to neurodegeneration are crucial to identify individuals at high risk. In patients with idiopathic REM sleep behavior disorder (iRBD), the strongest risk factor for neurodegeneration, CD4+ T cells exhibit a peculiar transcription factor pattern.Objective: To assess transcription factor mRNA levels in CD4+ T cells as predictive biomarkers of phenoconversion in iRBD patients.Methods: iRBD patients were followed prospectively. ROC curve analysis and Kaplan-Meier curves were used to assess the discrimination between converters and non-converters.Results: CD4+ T cells from converters had higher STAT1, and lower GATA3 and FOXP3 mRNA levels. Hazard ratio was 58.3 (95% CI: 6.2-547.1) for higher STAT1, 101.2 (95% CI: 16.8-609.4) for lower GATA3 and 15.7 (2.7-91.4) for lower FOXP3.Conclusion: STAT1, GATA3 and FOXP3 mRNA levels in CD4+ T cells are promising predictive biomarkers of phenoconversion in iRBD patients.

Brain 18FDG-PET pattern in cognitively impaired elderly patients with bipolar disorder

BACKGROUND

Patients with bipolar disorder (BD) are at increased risk of dementia. The underlying mechanisms are debated. FDG-PET elucidates glucose metabolic reductions due to altered neuronal activity in the cerebral cortex, allowing detection and identification of neurodegenerative processes. This study aims to investigate cerebral glucose metabolism in cognitively impaired elderly patients with BD using FDG-PET imaging, to elucidate potential underlying mechanisms and improve diagnostic accuracy.

METHODS

We conducted a retrospective analysis of FDG-PET scans from 32 cognitively impaired elderly patients with BD (mean age 70.4 years). These were compared with scans from 35 non-degenerative controls (NDC) and patients diagnosed with Alzheimer's disease (AD, n = 27), frontotemporal dementia (FTD, n = 26), and dementia with Lewy bodies (DLB, n = 18). Voxel-wise statistical analysis was performed using SPM software, adjusting for age and sex.

RESULTS

No significant cortical hypometabolism was found in patients with BD compared to NDC. In contrast, typical patterns of hypometabolism were observed in the AD, FTD, and DLB groups. The findings suggest that late-life cognitive impairment in patients with BD is not due to a single common neurodegenerative process.

CONCLUSION

The absence of abnormal cortical metabolism in cognitively impaired elderly patients with BD suggests that cognitive impairment in this population may not be driven by a common neurodegenerative pathway. Further studies using other biomarkers are needed to investigate the brain processes involved, which could lead to improved understanding and management of cognitive impairment in patients with BD.

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.

Concordance and test-retest consistency of sleep biomarker-based neurodegenerative disorder profiling

Biomarkers that aid in early detection of neurodegeneration are needed to enable early symptomatic treatment and enable identification of people who may benefit from neuroprotective interventions. Increasing evidence suggests that sleep biomarkers may be useful, given the bi-directional relationship between sleep and neurodegeneration and the prominence of sleep disturbances and altered sleep architectural characteristics in several neurodegenerative disorders. This study aimed to demonstrate that sleep can accurately characterize specific neurodegenerative disorders (NDD). A four-class machine-learning algorithm was trained using age and nine sleep biomarkers from patients with clinically-diagnosed manifest and prodromal NDDs, including Alzheimer's disease dementia (AD = 27), Lewy body dementia (LBD = 18), and isolated REM sleep behavior disorder (iRBD = 15), as well as a control group (CG = 58). The algorithm was validated in a total of 381 recordings, which included the training data set plus an additional AD = 10, iRBD = 18, Parkinson disease without dementia (PD = 29), mild cognitive impairment (MCI = 78) and CG = 128. Test-retest consistency was then assessed in LBD = 10, AD = 9, and CG = 46. The agreement between the NDD profiles and their respective clinical diagnoses exceeded 75% for the AD, LBD, and CG, and improved when NDD participants classified Likely Normal with NDD indications consistent with their clinical diagnosis were considered. Profiles for iRBD, PD and MCI participants were consistent with the heterogeneity of disease severities, with the majority of overt disagreements explained by normal sleep characterization in 27% of iRBD, 21% of PD, and 26% of MCI participants. For test-retest assignments, the same or similar NDD profiles were obtained for 88% of LBD, 86% in AD, and 98% of CG participants. The potential utility for NDD subtyping based on sleep biomarkers demonstrates promise and requires further prospective development and validation in larger NDD cohorts.

Alzheimer's Association clinical practice guideline for the Diagnostic Evaluation, Testing, Counseling, and Disclosure of Suspected Alzheimer's Disease and Related Disorders (DETeCD-ADRD): Executive summary of recommendations for primary care

US clinical practice guidelines for the diagnostic evaluation of cognitive impairment due to Alzheimer's disease (AD) or AD and related dementias (ADRD) are decades old and aimed at specialists. This evidence-based guideline was developed to empower all-including primary care-clinicians to implement a structured approach for evaluating a patient with symptoms that may represent clinical AD/ADRD. Through a modified-Delphi approach and guideline-development process (7374 publications were reviewed; 133 met inclusion criteria) an expert workgroup developed recommendations as steps in a patient-centered evaluation process. This summary focuses on recommendations, appropriate for any practice setting, forming core elements of a high-quality, evidence-supported evaluation process aimed at characterizing, diagnosing, and disclosing the patient's cognitive functional status, cognitive-behavioral syndrome, and likely underlying brain disease so that optimal care plans to maximize patient/care partner dyad quality of life can be developed; a companion article summarizes specialist recommendations. If clinicians use this guideline and health-care systems provide adequate resources, outcomes should improve in most patients in most practice settings. Highlights US clinical practice guidelines for the diagnostic evaluation of cognitive impairment due to Alzheimer's disease (AD) or AD and related dementias (ADRD) are decades old and aimed at specialists. This evidence-based guideline was developed to empower all-including primary care-clinicians to implement a structured approach for evaluating a patient with symptoms that may represent clinical AD/ADRD. This summary focuses on recommendations, appropriate for any practice setting, forming core elements of a high-quality, evidence-supported evaluation process aimed at characterizing, diagnosing, and disclosing the patient's cognitive functional status, cognitive-behavioral syndrome, and likely underlying brain disease so that optimal care plans to maximize patient/care partner dyad quality of life can be developed; a companion article summarizes specialist recommendations. If clinicians use this guideline and health-care systems provide adequate resources, outcomes should improve in most patients in most practice settings.

Cerebrospinal Fluid Classical Biomarker Levels in Mixed vs. Pure A+T+ (A+T1+) Alzheimer's Disease

Background: Alzheimer's disease (AD) may present with pure (typical or atypical) and mixed phenotypes, sometimes causing difficulties in (differential) diagnosis. In order to achieve a diagnostic accuracy as high as possible, the diagnosis of AD during life depends on various biomarkers, including the cerebrospinal fluid (CSF) biomarkers. Methods: Classical CSF AD biomarkers were determined in a total of 61 patients, classified as both beta amyloid- and tau-positive A+T+ (or A+T1+ according to the recently revised Alzheimer Association criteria for diagnosis and staging of AD). Twenty one of these patients fulfilled the criteria for mixed AD (mixed with Lewy bodies, cerebrovascular disease, or normal pressure hydrocephalus), whilst 40 had pure AD. Results: Patients did not differ with respect to gender, education, disease duration, and cognitive status. After controlling for confounding factors, no difference was observed between mixed and pure AD groups in Aβ42 or Aβ42/Aβ40 levels. Although by definition, patients of both groups had abnormal (increased) levels of phospho-tau181, the mixed AD group presented with lower (less abnormal) levels of phospho-tau181 and total tau as compared to the pure group. Conclusions: In patients with AD of comparable cognitive status, mixed AD cases may present with lower levels of tau proteins and, if close to the cut-off values, diagnostic uncertainty may be increased.

Cognitive decline profiles associated with lewy pathology in the context of Alzheimer's disease neuropathologic change

BACKGROUND

Alzheimer's disease neuropathologic change (ADNC) and Lewy pathology (LP) often coexist in cognitively impaired individuals. These pathologies' relative distribution and severity may modify these individuals' clinical presentation, cognitive profile, and prognosis. Therefore, we examined the contributions of LP and concomitant ADNC to disease survival and profiles of cognitive decline in preclinical and clinical stages in a large neuropathologically diagnosed group.

METHODS

We evaluated 597 participants with LP and 491 participants with intermediate/high ADNC in the absence of LP from the National Alzheimer Coordinating Center (NACC) database. At baseline, 237 participants were cognitively normal (CN), 255 were diagnosed with mild cognitive impairment (MCI), and 596 with dementia. Cognition was assessed using three cognitive domain scores (i.e., Memory, Executive, and Language) from the NACC Uniform Dataset (UDS) neuropsychological test battery, MMSE, and Clinical Dementia Rating (CDR). Multivariate adaptive regression splines were used to evaluate associations between baseline cognitive scores and mean annual rate of change over two years. The likelihood of progression to MCI or dementia was assessed using Cox hazard models.

RESULTS

Neocortical LP, independent of the clinical diagnosis, was associated with lower Executive and higher Language and Memory scores at baseline, whereas Braak V-VI neurofibrillary tangle pathology was associated with lower Memory and Language scores. Similarly, neocortical LP was associated with faster Executive decline, whereas Braak V-VI neurofibrillary tangle pathology was associated with faster Memory and Language decline. A clinical diagnosis of Lewy Body Dementia (i.e., a strong LP phenotype) was associated with the LP cognitive profile and shorter disease duration. Progression to incident MCI or dementia was primarily associated with the degree of tau pathology; neocortical LP or a diagnosis of Lewy Body Dementia only predicted progression when those with intermediate/high ADNC were excluded.

CONCLUSIONS

LP and ADNC differentially affected cross-sectional and longitudinal cognitive profiles in a large autopsy sample. Concomitant Braak V-VI neurofibrillary tangle pathology had a strong impact on clinical progression in those with LP, regardless of the initial stage. Thus, LB and ADNC co-pathology interact to affect cognitive domains that may be used to track Lewy Body disease longitudinally and as outcome measures in therapeutic trials.

18F-PI-2620 Tau PET is associated with cognitive and motor impairment in Lewy body disease

Co-pathology is frequent in Lewy body disease, which includes clinical diagnoses of both Parkinson's disease and dementia with Lewy bodies. Measuring concomitant pathology in vivo can improve clinical and research diagnoses and prediction of cognitive trajectories. Tau PET imaging may serve a dual role in Lewy body disease by measuring cortical tau aggregation as well as assessing dopaminergic loss attributed to binding to neuromelanin within substantia nigra. We sought to characterize 18F-PI-2620, a next generation PET tracer, in individuals with Lewy body disease. We recruited 141 participants for 18F-PI-2620 PET scans from the Stanford Alzheimer's Disease Research Center and the Stanford Aging and Memory Study, most of whom also had β-amyloid status available (139/141) from PET or cerebrospinal fluid. We compared 18F-PI-2620 uptake within entorhinal cortex, inferior temporal cortex, precuneus and lingual gyrus, as well as substantia nigra, across participants with Lewy body disease [Parkinson's disease (n = 29), dementia with Lewy bodies (n = 14)] and Alzheimer's disease (n = 28), in addition to cognitively unimpaired healthy older adults (n = 70). Mean bilateral signal was extracted from cortical regions of interest in 18F-PI-2620 standard uptake value ratio (inferior cerebellar grey reference) images normalized to template space. A subset of participants received cognitive testing and/or the Movement Disorders Society Unified Parkinson's Disease Rating Scale Part III motor exam (off medication). 18F-PI-2620 uptake was low overall in Lewy body disease and correlated with β-amyloid PET in temporal lobe regions and precuneus. Moreover, inferior temporal 18F-PI-2620 uptake was significantly elevated in β-amyloid positive relative to β-amyloid negative participants with Lewy body disease. Temporal lobe 18F-PI-2620 signal was not associated with memory in Lewy body disease, but uptake within precuneus and lingual gyrus was associated with worse executive function and attention/working memory performance. Finally, substantia nigra 18F-PI-2620 signal was significantly reduced in participants with Parkinson's disease, and lower substantia nigra signal was associated with greater motor impairment. These findings suggest that although levels are lower than in Alzheimer's disease, small elevations in cortical tau are associated with cognitive function in Lewy body disease relevant domains, and that reduced 18F-PI-2620 binding in substantia nigra may represent loss of dopaminergic neurons. Cortical tau and neuromelanin binding within substantia nigra represent two unique signals in the same PET image that may be informative in the context of cognitive and motor deficits, respectively, in Lewy body disease.

The Diagnostic Value of Cerebrospinal Fluid Neurogranin in Neurodegenerative Diseases

Synaptic pathology is crucial in neurodegenerative diseases (NDs), and numerous studies show a correlation between synaptic proteins and the rate of cognitive decline in Alzheimer's disease, Parkinson's disease, dementia, and Creutzfeldt-Jacob's disease. Due to the fact that altered synaptic function is considered a core feature of the pathophysiology of neurodegenerative disorders, synaptic proteins, such as neurogranin, may serve as a biomarker of these diseases. Neurogranin is a postsynaptic protein located in the cell bodies and dendrites of neurons, foremost in the cerebral cortex, hippocampus, and striatum. It has been established that neurogranin is involved in synaptic plasticity and long-term potentiation. Literature data indicate that cerebrospinal fluid neurogranin may be useful as a biomarker for more accurate diagnosis and prognosis of neurodegenerative diseases. In this review, the diagnostic value of cerebrospinal fluid neurogranin in most common neurodegenerative diseases is examined.

Comparative mapping of single-cell transcriptomic landscapes in neurodegenerative diseases

INTRODUCTION

Alzheimer's disease (AD), Dementia with Lewy bodies (DLB), and Parkinson's disease (PD) represent a spectrum of neurodegenerative disorders (NDDs). Here, we performed the first direct comparison of their transcriptomic landscapes.

METHODS

We profiled the whole transcriptomes of NDD cortical tissue by snRNA-seq. We used computational analyses to identify common and distinct differentially expressed genes (DEGs), biological pathways, vulnerable and disease-driver cell subtypes, and alteration in cell-to-cell interactions.

RESULTS

The same vulnerable inhibitory neuron subtype was depleted in both AD and DLB. Potentially disease-driving neuronal cell subtypes were present in both PD and DLB. Cell-cell communication was predicted to be increased in AD but decreased in DLB and PD. DEGs were most commonly shared across NDDs within inhibitory neuron subtypes. Overall, we observed the greatest transcriptomic divergence between AD and PD, while DLB exhibited an intermediate transcriptomic signature.

DISCUSSION

These results help explain the clinicopathological spectrum of this group of NDDs and provide unique insights into the shared and distinct molecular mechanisms underlying the pathogenesis of NDDs.

Cuneus atrophy and Parkinsonian phenoconversion in cognitively unimpaired patients with isolated REM sleep behavior disorder

Isolated rapid-eye-movement sleep behavior disorder (iRBD) is a strong predictor of Parkinson's disease and Dementia with Lewy bodies. Previous studies indicate that cortical atrophy in iRBD patients may be linked to cognitive impairment, but the pattern of atrophy is inconsistently reported. This study aimed to elucidate cortical atrophy patterns in a cognitively unimpaired iRBD cohort, focusing on regions associated with cognitive functions, particularly the cuneus/precuneus, and evaluated the predictive value for future phenoconversion. We conducted voxel-based morphometry and region of interest (ROI) analysis of structural MRI scans of 36 healthy controls and 19 iRBD patients, nine of whom also received a 3-year follow-up MRI scan. The iRBD patients were followed clinically for 8 years, and time-to-event analyses, using Cox regression, were performed based on baseline ROI volumes. The iRBD patients had lower gray-matter volume in the cuneus/precuneus region as well as in subcortical structures (caudate nuclei and putamen) compared to controls. Eight iRBD patients developed either Parkinson's disease (N = 4) or Dementia with Lewy bodies (N = 4) during the follow-up period. Time-to-event analyses showed that lower right cuneus volume was associated with a higher risk of phenoconversion to alpha-synuclein-linked Parkinsonism in the iRBD patients (Hazard ratio = 13.0, CI: 1.53-110), and correlated with shorter time to conversion. In addition, lower volumes of the bilateral precuneus trended to indicate a higher risk of phenoconversion. These findings suggest a potential predictive value of cuneus and precuneus volumes in identifying iRBD patients at risk of disease progression, even before the onset of cognitive impairment.

Subject-Level Segmentation Precision Weights for Volumetric Studies Involving Label Fusion

In neuroimaging research, volumetric data contribute valuable information for understanding brain changes during both healthy aging and pathological processes. Extracting these measures from images requires segmenting the regions of interest (ROIs), and many popular methods accomplish this by fusing labels from multiple expert-segmented images called atlases. However, post-segmentation, current practices typically treat each subject's measurement equally without incorporating any information about variation in their segmentation precision. This naïve approach hinders comparing ROI volumes between different samples to identify associations between tissue volume and disease or phenotype. We propose a novel method that estimates the variance of the measured ROI volume for each subject due to the multi-atlas segmentation procedure. We demonstrate in real data that weighting by these estimates markedly improves the power to detect a mean difference in hippocampal volume between controls and subjects with mild cognitive impairment or Alzheimer's disease.

REM sleep behavior disorder and Prodromal Parkinson's Disease in patients with Essential Tremor

Several studies suggested the presence of non-motor symptoms in Essential Tremor (ET), including REM sleep behavioral disorder (RBD). RBD is an essential criterion for Prodromal Parkinson's Disease (PPD), suggesting a link between ET and PD. Our objective was to assess the prevalence and features of ET patients with RBD and PDD. RBD was diagnosed by questionnaire screening, followed by polysomnography. PPD risk factors and prodromic markers were assessed with a structured protocol. Patients were characterized regarding tremor features. ET patients with RBD (ET-RBD) and PPD (ET-PPD) were compared to patients without RBD (ET-nonRBD) and without PPD (ET-nonPPD), respectively. ET-RBD patients were also compared with a group of isolated RBD (iRBD) regarding PPD features. We assessed a total of 64 ET patients. Five (8.3 %) and 4 (6.3 %) had criteria for RBD and PPD, respectively. ET-RBD patients did not differ from ET-nonRBD except for a higher prevalence of PPD. There were no significant differences between ET-RBD and iRBD (n = 12) groups. ET-PPD had a higher prevalence of positive DaT-Scans and RBD compared to ET-nonPPD. Three ET-RBD patients had PPD and 3 ET-PPD had RBD. Both RBD and PPD are more frequent in ET patients than in general aged population but not related with specific tremor features. ET-RBD patients did not differ significantly from iRBD patients, a group prone to develop PD. These data suggest a link between ET and PD and are in accordance with studies showing an increase incidence of lewy-body pathology and PD in ET populations.

Utility of Tau PET in the diagnostic work up of neurodegenerative dementia among Indian patients

BACKGROUND AND OBJECTIVES

Tau PET is being increasingly appraised as a novel diagnostic modality for dementia work up. Given limited data among South Asians, we assessed the frequency, patterns, phenotypic associations and incremental value of positive Tau PET scans in clinically diagnosed neurodegenerative dementia.

METHODS

This cross-sectional study recruited consecutive patients of Alzheimer's disease (AD) and non-AD syndromes (September 2021 to October 2022, India). Participants underwent clinical interview, cognitive assessment, MRI brain and tau PET scan ([F-18]ML-104). Visual read in a priori regions of interest was used to identify patterns of tau deposition in the brain.

RESULTS

We recruited 54 participants (mean age: 63.2 ± 9.2 years, 64.8 % men, 77.8 % dementia, 70.4 % early onset cases, 37.8 % APOE4+). The analysis identified abnormal tau uptake in 40/54 (74.1 %) participants; with uptake in AD signature areas in 27/40 (67.5 %) cases [cortical subtype (74.1 %), limbic (14.8 %), combined cortical/limbic (11.1 %)], and patterns not conforming to AD in 13/40 (32.5 %) cases. Tau PET substantiated the diagnosis of AD among 17/19 (89.5 %) cases with clinically diagnosed AD dementia, 8/23 (34.8 %) cases with suspected non-AD cause, and 2/12 (16.7 %) cases with mild cognitive impairment. A trend for increasing proportion of early onset cases, and worsening cognition, behavior and functional ability was seen, from 'limbic' to 'combined cortical/limbic' to 'cortical' subgroups.

CONCLUSION

Tau PET is a useful modality to differentiate AD dementia from other neurodegenerative causes in the Indian setting where amyloid biomarkers are not widely available. Biological subtypes of AD map well onto clinical phenotypes and need study in larger cohorts.

Investigating the potential of novel thiazole derivatives in treating Alzheimer's and Parkinson's diseases

The study aimed to investigate 12 novel thiazole compounds in the treatment of neurodegenerative disorders. The compounds produced were evaluated for their inhibitory efficacy against acetylcholinesterase (AChE), butyrylcholinesterase (BChE), and monoamine oxidases (MAOs). Among the compounds, 5d, 5e, and 5j showed the highest AChE inhibitory activity. The IC50 values for compounds are 0.223 ± 0.010 µM, 0.092 ± 0.003 µM, and 0.054 ± 0.002 µM, respectively. In addition, molecular docking analyses and molecular dynamic simulation were used to examine the interactions of these compounds with protein sites. The results suggest that thiazole-ring compounds could serve as a promising basis for the development of drugs aimed at treating neurodegenerative diseases (NDD), caused by Parkinson's and Alzheimer's diseases.

What is the future for dementia with Lewy bodies?

Dementia with Lewy bodies (DLB) is the second most common neurodegenerative dementia after Alzheimer's disease (AD), yet it remains under-recognized and frequently misdiagnosed due to heterogenous clinical presentations, the presence of co-pathology, and the lack of specific diagnostic tools. Pathologically, DLB is characterized by the accumulation of misfolded alpha-synuclein (aSyn) aggregates, known as Lewy bodies. Recent advancements have improved in vivo detection of aSyn pathology through techniques such as seed amplification assays, monoclonal antibodies, and positron emission tomography using novel small-molecule ligands. The ability to detect aSyn in vivo has sparked dialogue about using biomarkers to identify individuals with aSyn, similar to the approach influencing the field of AD. Proponents argue that biological staging could facilitate the detection of preclinical disease stages, allowing for earlier intervention and targets for disease modification, and could improve diagnostic sensitivity and accuracy in selecting patients for clinical trials. However, critics caution that this method may oversimplify the complexity of DLB and overlook its clinical heterogeneity, also highlighting practical challenges related to implementation, cost, and global access to advanced diagnostic technologies. Importantly, although significant progress has been made in detecting aSyn for diagnostic purposes, disease-modifying therapies targeting aSyn have yet to demonstrate clear efficacy in slowing disease progression. Elucidating the physiological and pathophysiological roles of aSyn remains an urgent priority in neurodegenerative research. Other experimental research priorities for DLB include developing improved cellular and animal models that reflect epigenetic and environmental factors, mapping post-translational modifications, and systematically characterizing neurons that are vulnerable and resistant to lewy pathology using a multi-omic approach. Clinically, there is an urgent need for international, prospective, longitudinal studies and for validated, disease-specific outcome measures. Addressing these priorities is essential for advancing our understanding of DLB and developing effective therapies.

Myelin basic protein and TREM2 quantification in the CSF of patients with Multiple System Atrophy and other Parkinsonian conditions

BACKGROUND

It is well known that myelin disruption and neuroinflammation are early and distinct pathological hallmarks in multiple system atrophy (MSA) as well as in idiopathic Parkinson's disease and in other atypical Parkinsonian syndromes. The objective of this study was to assess the value of non-neuronal biomarker candidates that reflect myelin disruption and neuroinflammation.

METHODS

Myelin basic protein (MBP) and the soluble form of TREM2 were quantified in a comprehensive movement disorder cohort from two different neurological centers, comprising a total of 171 CSF samples. Commercially available ELISA systems were employed for quantification.

RESULTS

The results of the MBP analysis revealed a significant increase in cerebrospinal fluid (CSF) MBP levels in all atypical Parkinsonian conditions compared to PD. This differentiation was more pronounced in the MSA-c subtype compared to MSA-p. Receiver operating characteristic (ROC) analysis revealed a significant discrimination between PD and MSA (p = 0.032, AUC = 0.70), PD and DLB (p = 0.006, AUC = 0.79) and PD and tauopathies (p = 0.006, AUC = 0.74). The results of the TREM2 analysis demonstrated no significant differences between the PD and atypical Parkinsonian groups if not adjusted for confounders. After adjusting for age, sex, and disease duration, the PD group exhibited significantly higher TREM2 levels compared to the DLB group (p = 0.002).

CONCLUSIONS

In conclusion, MBP, but not TREM2, is elevated in the CSF of not only MSA but in all atypical Parkinsonian conditions compared to idiopathic Parkinson's disease. This highlights the value of the evaluation of myelin/oligodendrocyte-associated markers in neurodegenerative movement disorders.

Neuroanatomical and clinical correlates of prodromal dementia with Lewy bodies: a systematic literature review of neuroimaging findings

Prodromal Dementia with Lewy bodies (pro-DLB) has been recently defined; however, the neuroanatomical and functional correlates of this stage have not yet been univocally established. This study aimed to systematically review neuroimaging findings focused on pro-DLB. A literature search of works employing MRI, PET, and SPECT was performed. Forty records were included: 15 studies assessed gray matter (GM) and white matter (WM) integrity, and 31 investigated metabolism, perfusion, and resting-state connectivity. Results showed that, in pro-DLB, frontal lobe areas were characterized by decreased function, cortical atrophy, and WM damage. Volumetric reductions were found in the insula, which also showed heightened metabolism. A pattern of hypofunction and structural damage was observed in the lateral and ventral temporal lobe; instead, the parahippocampal cortex and hippocampus exhibited greater function. Hypofunction marked parietal and occipital regions, with additional atrophy in the medial occipital lobe and posterior parietal cortex. Subcortically, atrophy and microstructural damage in the nucleus basalis of Meynert were reported, and dopamine transporter uptake was reduced in the basal ganglia. Overall, structural and functional damage was already present in pro-DLB and was coherent with the possible clinical onset. Frontal and parieto-occipital alterations may be associated with deficits in attention and executive functions and in visuo-perceptual/visuo-spatial abilities, respectively. Degeneration of cholinergic and dopaminergic transmission appeared substantial at this disease stage. This review provided an updated and more precise depiction of the brain alterations that are specific to pro-DLB and valuable to its differentiation from physiological aging and other dementias.

Electroencephalogram rhythmic and arrhythmic spectral components and functional connectivity at resting state may predict the development of synucleinopathies in idiopathic rapid eye movement sleep behavior disorder

STUDY OBJECTIVES

Idiopathic/isolated rapid eye movement-sleep behavior disorder (iRBD) often precedes the onset of synucleinopathies. Here, we investigated whether baseline resting-state EEG advanced spectral power and functional connectivity differed between iRBD patients who converted towards a synucleinopathy at follow-up and those who did not.

METHODS

Eighty-one participants with iRBD (66.89 ± 6.91 years) underwent a baseline resting-state EEG recording, a neuropsychological assessment, and a neurological examination. We estimated EEG power spectral density using standard analyses and derived spectral estimates of rhythmic and arrhythmic components. Global and pairwise EEG functional connectivity analyses were computed using the weighted phase-lag index (wPLI). Pixel-based permutation tests were used to compare groups.

RESULTS

After a mean follow-up of 5.01 ± 2.76 years, 34 patients were diagnosed with a synucleinopathy (67.81 ± 7.34 years) and 47 remained disease-free (65.53 ± 7.09 years). Among patients who converted, 22 were diagnosed with Parkinson's disease and 12 with dementia with Lewy bodies. As compared to patients who did not convert, patients who converted exhibited at baseline higher relative theta standard power, steeper slopes of the arrhythmic component and higher theta rhythmic power mostly in occipital regions. Furthermore, patients who converted showed higher beta global wPLI but lower alpha wPLI between left temporal and occipital regions.

CONCLUSIONS

Analyses of resting-state EEG rhythmic and arrhythmic components and functional connectivity suggest an imbalanced excitatory-to-inhibitory activity within large-scale networks, which is associated with later development of a synucleinopathy in patients with iRBD.

Impact of Lewy bodies disease on visual skills and memory abilities: from prodromal stages to dementia

Dementia with Lewy bodies (DLB) and its prodromal presentation with mild cognitive impairment is characterized by prominent deficits in attention/executive domains and in visual processing abilities with relative sparing of memory. Neuropsychological research is continuously refining the tools to define more in detail the patterns of relatively preserved and impaired cognitive abilities that help differential diagnosis between DLB and Alzheimer disease (AD). This review summarizes the main studies exploring specific cognitive tasks investigating different visual processing abilities and verbal memory that better differentiate DLB from AD. The findings provide evidence that substantial impairments in visual-spatial and visual-constructional abilities and relatively better performance on memory tasks that depend on hippocampal function characterize the prodromal stage of DLB. The ability to detect early indicators of prodromal DLB through clinical and cognitive assessments is the first step to guide instrumental diagnostic work-ups and provide the opportunity for early intervention.

Atypical Parkinsonian Syndromes: Structural, Functional, and Molecular Imaging Features

Atypical parkinsonian syndromes, also known as Parkinson-plus syndromes, are a heterogeneous group of movement disorders, including dementia with Lewy bodies (DLB), progressive supranuclear palsy (PSP), multisystem atrophy (MSA), and corticobasal degeneration (CBD). This review highlights the characteristic structural, functional, and molecular imaging features of these complex disorders. DLB typically demonstrates parieto-occipital hypometabolism with involvement of the cuneus on FDG-PET, whereas dopaminergic imaging, such as [123I]-FP-CIT SPECT (DaTscan) or fluorodopa (FDOPA)-PET, can be utilized as an adjunct for diagnosis. PSP typically shows midbrain atrophy on structural imaging, whereas FDG-PET may be useful to depict frontal lobe hypometabolism and tau-PET confirms underlying tauopathy. MSA typically demonstrates putaminal or cerebellar atrophy, whereas FDG-PET highlights characteristic nigrostriatal or olivopontocerebellar hypometabolism, respectively. Finally, CBD typically shows asymmetric atrophy in the superior parietal lobules and corpus callosum, whereas FDG and tau-PET demonstrate asymmetric hemispheric and subcortical involvement contralateral to the side of clinical deficits. Additional advanced neuroimaging modalities and techniques described may assist in the diagnostic work-up or are promising areas of emerging research.

Psychiatric Disorders and Cognitive Fluctuations in Parkinson's Disease: Changing Approaches in the First Decades of the 21st Century

Parkinson's Disease (PD) is a multifaceted neurodegenerative disorder characterized, in addition to the well-recognized motor disturbances, by a complex interplay between cognitive and psychiatric manifestations. We dissect the complex landscape of PD-related psychiatric symptoms, taking into account the impact of functional neurological disorders, somatic delusions, impulse control disorders, and conditions within the bipolar spectrum. The newer entities of somatoform and functional neurological disorders, as well as preexisting bipolar spectrum disorders, are analyzed in detail. Moreover, we emphasize the need for a holistic understanding of PD, wherein the cognitive and psychiatric dimensions are valued alongside motor symptoms. Such an approach aims to facilitate early detection and personalized interventions, and enhance the overall quality of life for individuals suffering from this neurodegenerative disorder.

Posterior hippocampal sparing in Lewy body disorders with Alzheimer's copathology: An in vivo MRI study

BACKGROUND

Lewy body disorders (LBD), encompassing Parkinson disease (PD), PD dementia (PDD), and dementia with Lewy bodies (DLB), are characterized by alpha-synuclein pathology but often are accompanied by Alzheimer's disease (AD) neuropathological change (ADNC). The medial temporal lobe (MTL) is a primary locus of tau accumulation and associated neurodegeneration in AD. However, it is unclear the extent to which AD copathology in LBD (LBD/AD+) contributes to MTL-specific patterns of degeneration. We employ a MTL subregional segmentation strategy of T1-weighted (T1w) MRI in biomarker-supported or autopsy-confirmed LBD and LBD/AD+ to investigate the anatomic consequences of co-occurring LBD/AD+ pathology on neurodegeneration.

METHODS

We studied 167 individuals with clinical diagnoses of LBD (PD, n = 124 (74.3 %); PDD, n = 11 (6.6 %); DLB, n = 32 (19.2 %)) with available T1w MRI and AD biomarkers or autopsy evidence of ADNC. Individuals were further biologically classified as LBD/AD+ based on hierarchical evidence of ADNC pathology: 1) AD "intermediate" or "high" by ABC neuropathologic criteria (n = 39 (23.4 %)); 2) positive amyloid PET (n = 2 (1.2 %)); or 3) CSF β-amyloid1-42 < 185.7 pg/mL n = 126 (75.4 %)). The T1 Automated Segmentation of Hippocampal Subfields (ASHS) pipeline was used to compute volume and thickness measurements of MTL subregions in LBD/AD- and LBD/AD+. Linear regression tested the association of AD copathology and subregion volume/thickness, covarying for age and sex, and intracranial volume for volume measurements. Secondary analyses correlated MTL subregional volume/thickness with cognition and neuropathology.

RESULTS

LBD/AD+ had decreased volume/thickness compared to LBD/AD- in all MTL subregions except posterior hippocampus. The greatest effect sizes were seen in Brodmann Area 35 (BA35) (Cohen's d = 0.62, p = 0.002, β = 0.107 ± 0.034), and entorhinal cortex (ERC) (Cohen's d = 0.56, p = 0.006, β = 0.088 ± 0.031). Smaller differences were seen in the parahippocampal cortex (PHC) (Cohen's d = 0.5, p = 0.012, β = 0.082 ± 0.033), BA36 (Cohen's d = 0.47, p = 0.021, β = 0.090 ± 0.039) and anterior hippocampus (Cohen's d = 0.45, p = 0.029, β = 111.790 ± 50.595). Verbal memory scores positively correlated with volume/thickness in anterior and posterior hippocampus, BA35, ERC and PHC, while visuospatial memory positively correlated only in BA35. In the subset of participants with autopsy, lower ERC volume was associated with a higher tau load in ERC (adjusted odds ratio 0.013, 95 % CI [0.0002, 0.841], uncorrected p = 0.041).

CONCLUSIONS

Relative to LBD/AD-, LBD/AD+ has greater T1w MRI evidence of atrophy in multiple MTL subregions. Atrophy in MTL subregions associates with memory performance and tau pathological load. The observed pattern of atrophy largely follows expectation from AD Braak stages, except for posterior hippocampus. Longitudinal studies are needed to validate the hypothesized spread of neurodegeneration.

Longitudinal changes in cardiac mIBG scintigraphy in mild cognitive impairment with Lewy bodies

The aim of this study was to determine whether there was a significant change in cardiac [123I]-metaiodobenzylguanidine uptake between baseline and follow-up in individuals with mild cognitive impairment with Lewy bodies (MCI-LB) who had normal baseline scans. Eight participants with a diagnosis of probable MCI-LB and a normal baseline scan consented to a follow-up scan between 2 and 4 years after baseline. All eight repeat scans remained normal; however, in three cases uptake decreased by more than 10%. The mean change in uptake between baseline and repeat was -5.2% (range: -23.8% to +7.0%). The interpolated mean annual change in uptake was -1.6%.

Autoantibody profiles in Alzheimer´s, Parkinson´s, and dementia with Lewy bodies: altered IgG affinity and IgG/IgM/IgA responses to alpha-synuclein, amyloid-beta, and tau in disease-specific pathological patterns

BACKGROUND

Alzheimer's disease (AD) and Parkinson's disease (PD) are leading neurodegenerative disorders marked by protein aggregation, with AD featuring amyloid-beta (Aβ) and tau proteins, and PD alpha-synuclein (αSyn). Dementia with Lewy bodies (DLB) often presents with a mix of these pathologies. This study explores naturally occurring autoantibodies (nAbs), including Immunoglobulin (Ig)G, IgM, and IgA, which target αSyn, Aβ and tau to maintain homeostasis and were previously found altered in AD and PD patients, among others.

MAIN TEXT

We extended this investigation across AD, PD and DLB patients investigating both the affinities of IgGs and levels of IgGs, IgMs and IgAs towards αSyn, Aβ and tau utilizing chemiluminescence assays. We confirmed that AD and PD patients exhibited lower levels of high-affinity anti-Aβ and anti-αSyn IgGs, respectively, than healthy controls. AD patients also showed diminished levels of high-affinity anti-αSyn IgGs, while anti-tau IgG affinities did not differ significantly across groups. However, DLB patients exhibited increased anti-αSyn IgG but decreased anti-αSyn IgM levels compared to controls and PD patients, with AD patients showing a similar pattern. Interestingly, AD patients had higher anti-Aβ IgG but lower anti-Aβ IgA levels than DLB patients. DLB patients had reduced anti-Aβ IgM levels compared to controls, and anti-tau IgG levels were lower in AD than PD patients, who had reduced anti-tau IgM levels compared to controls. AD patients uniquely showed higher anti-tau IgA levels. Significant correlations were observed between clinical measures and nAbs, with negative correlations between anti-αSyn IgG affinity and levels in DLB patients and a positive correlation with anti-αSyn IgA levels in PD patients. Disease-specific changes in nAb levels and affinity correlations were identified, highlighting altered immune responses.

CONCLUSION

This study reveals distinctive nAb profiles in AD, DLB, and PD, pinpointing specific immune deficiencies against pathological proteins. These insights into the autoreactive immune system's role in neurodegeneration suggest nAbs as potential markers for vulnerability to protein aggregation, offering new avenues for understanding and possibly diagnosing these conditions.

Gba1 E326K renders motor and non-motor symptoms with pathological α-synuclein, tau and glial activation

Mutations in the GBA1 gene are common genetic risk factors for Parkinson's disease, disrupting enzymatic activity and causing lysosomal dysfunction, leading to elevated α-synuclein levels. Although the role of GBA1 in synucleinopathy is well established, recent research underscores neuroinflammation as a significant pathogenic mechanism in GBA1 deficiency. This study investigates neuroinflammation in Gba1 E326K knock-in mice, a model associated with increased risk of Parkinson's disease and dementia. At 9 and 24 months, we assessed GBA1 protein and activity, α-synuclein pathology, neurodegeneration, motor deficits and gliosis in the ventral midbrain and hippocampus using immunohistochemistry, western blot and glucocerebrosidase assays. Additionally, primary microglia from wild-type and Gba1E326K/E326K mice were treated with α-synuclein preformed fibrils to study microglia activation, pro-inflammatory cytokines, reactive astrocyte formation and neuronal death through quantitative PCR, western blot and immunocytochemistry analyses. We also evaluated the effects of gut inoculation of α-synuclein preformed fibrils in Gba1 E326K mice at 7 months and striatal inoculation at 10 months after injection, assessing motor/non-motor symptoms, α-synuclein pathology, neuroinflammation, gliosis and neurodegeneration via behavioural tests, immunohistochemistry and western blot assays. At 24 months, Gba1 E326K knock-in mice showed reduced glucocerebrosidase enzymatic activity and glucosylceramide build-up in the ventral midbrain and hippocampus. Increased pro-inflammatory cytokines and reactive astrocytes were observed in microglia and astrocytes from Gba1 E326K mice treated with pathological α-synuclein preformed fibrils. Gut inoculation of α-synuclein preformed fibrils increased Lewy body accumulation in the hippocampal dentate gyrus, with heightened microglia and astrocyte activation and worsened non-motor symptoms. Intrastriatal injection of α-synuclein preformed fibrils induced motor deficits, reactive glial protein accumulation and tauopathy in the prefrontal cortex and hippocampus of Gba1 E326K mice. GBA1 deficiency attributable to the Gba1 E326K mutation exacerbates neuroinflammation and promotes pathogenic α-synuclein transmission, intensifying disease pathology in Parkinson's disease models. This study enhances our understanding of how the Gba1 E326K mutation contributes to neuroinflammation and the spread of pathogenic α-synuclein in the brain, suggesting new therapeutic strategies for Parkinson's disease and related synucleinopathies.

Identification of isoAsp7-Aβ as a major Aβ variant in Alzheimer's disease, dementia with Lewy bodies and vascular dementia

The formation of amyloid-β (Aβ) aggregates in brain is a neuropathological hallmark of Alzheimer's disease (AD). However, there is mounting evidence that Aβ also plays a pathogenic role in other types of dementia and that specific post-translational Aβ modifications contribute to its pathogenic profile. The objective of this study was to test the hypothesis that distinct types of dementia are characterized by specific patterns of post-translationally modified Aβ variants. We conducted a comparative analysis and quantified Aβ as well as Aβ with pyroglutamate (pGlu3-Aβ and pGlu11-Aβ), N-truncation (Aβ(4-X)), isoaspartate racemization (isoAsp7-Aβ and isoAsp27-Aβ), phosphorylation (pSer8-Aβ and pSer26-Aβ) or nitration (3NTyr10-Aβ) modification in post mortem human brain tissue from non-demented control subjects in comparison to tissue classified as pre-symptomatic AD (Pre-AD), AD, dementia with Lewy bodies and vascular dementia. Aβ modification-specific immunohistochemical labelings of brain sections from the posterior superior temporal gyrus were examined by machine learning-based segmentation protocols and immunoassay analyses in brain tissue after sequential Aβ extraction were carried out. Our findings revealed that AD cases displayed the highest concentrations of all Aβ variants followed by dementia with Lewy bodies, Pre-AD, vascular dementia and non-demented controls. With both analytical methods, we identified the isoAsp7-Aβ variant as a highly abundant Aβ form in all clinical conditions, followed by Aβ(4-X), pGlu3-Aβ, pGlu11-Aβ and pSer8-Aβ. These Aβ variants were detected in distinct plaque types of compact, coarse-grained, cored and diffuse morphologies and, with varying frequencies, in cerebral blood vessels. The 3NTyr10-Aβ, pSer26-Aβ and isoAsp27-Aβ variants were not found to be present in Aβ plaques but were detected intraneuronally. There was a strong positive correlation between isoAsp7-Aβ and Thal phase and a moderate negative correlation between isoAsp7-Aβ and performance on the Mini Mental State Examination. Furthermore, the abundance of all Aβ variants was highest in APOE 3/4 carriers. In aggregation assays, the isoAsp7-Aβ, pGlu3-Aβ and pGlu11-Aβ variants showed instant fibril formation without lag phase, whereas Aβ(4-X), pSer26-Aβ and isoAsp27-Aβ did not form fibrils. We conclude that targeting Aβ post-translational modifications, and in particular the highly abundant isoAsp7-Aβ variant, might be considered for diagnostic and therapeutic approaches in different types of dementia. Hence, our findings might have implications for current antibody-based therapies of AD.

Autonomic nervous system dysfunction in idiopathic REM sleep behavior disorder as a short-term risk for a synucleinopathy

BACKGROUND

Idiopathic REM sleep behavior disorder (iRBD) is a prodromal marker of the alpha-synucleinopathies, in which autonomic nervous system (ANS) involvement may occur. We aimed to characterize the presence and severity of subjective and objective ANS dysfunction in iRBD and assess its capacity to predict short-term clinical progression to a synucleinopathy.

METHODS

Prospective study of patients with polysomnography-confirmed iRBD in whom symptomatic ANS involvement was assessed using the Composite Autonomic Symptom Score (COMPASS-31) and objective dysfunction with the Composite Autonomic Severity Score (CASS). Baseline ANS data were compared between those who later developed a synucleinopathy and those who did not.

RESULTS

We evaluated 25 subjects with iRBD without risk factors for autonomic neuropathy and at least 6 months of follow-up (mean: 19 months). At the end of the study, seven (28%) patients developed a synucleinopathy, namely Parkinson's disease (n = 5) and dementia with Lewy bodies (n = 2). 73.7% of patients had COMPASS-31 scores above the normal cut-off, while no score differences regarding phenoconversion status were observed. At baseline, 85.7% of the subjects who phenoconverted exhibited at least one abnormal result in the CASS score, compared to 38.9% of subjects who remained disease-free (p = 0.035). Adrenergic dysfunction evaluated by an impaired overshoot in Valsalva phase IV and by pressure recovery time was associated with the development of overt synucleinopathy (p = 0.032 and 0.033, respectively).

CONCLUSION

Symptomatic and subclinical ANS dysfunctions are common in iRBD. ANS dysfunction affecting mainly the adrenergic system seems to be a short-term risk for the development of a synucleinopathy.

Validation of the Japanese version of the Social Functioning in Dementia scale and COVID-19 pandemic's impact on social function in mild cognitive impairment and mild dementia

OBJECTIVES

We aimed to psychometrically evaluate and validate a Japanese version of the Social Functioning in Dementia scale (SF-DEM-J) and investigate changes in social function in people with dementia during the coronavirus disease-19 (COVID-19) pandemic.

DESIGN

We interviewed people with mild cognitive impairment (MCI) and mild dementia and their caregivers during June 2020-March 2021 to validate patient- and caregiver-rated SF-DEM-J and compared their scores at baseline (April 2020 to May 2020) and at 6-8 months (January 2021 to March 2021) during a time of tighter COVID-19 restrictions.

SETTING

The neuropsychology clinic in the Department of Psychiatry at Osaka University Hospital and outpatient clinic in the Department of Psychiatry and Neurology at Daini Osaka Police Hospital, Japan.

PARTICIPANTS

103 dyads of patients and caregivers.

MEASUREMENTS

SF-DEM-J, Mini-Mental State Examination, Neuropsychiatric Inventory, UCLA Loneliness Scale, and Apathy Evaluation Scale.

RESULTS

The scale's interrater reliability was excellent and test-retest reliability was substantial. Content validity was confirmed for the caregiver-rated SF-DEM-J, and convergent validity was moderate. Caregiver-rated SF-DEM-J was associated with apathy, irritability, loneliness, and cognitive impairment. The total score of caregiver-rated SF-DEM-J and the score of Section 2, "communication with others," significantly improved at 6-8 months of follow-up.

CONCLUSIONS

The SF-DEM-J is acceptable as a measure of social function in MCI and mild dementia. Our results show that the social functioning of people with dementia, especially communicating with others, improved during the COVID-19 pandemic, probably as a result of adaptation to the restrictive life.

Neuroanatomical substrates of depression in dementia with Lewy bodies and Alzheimer's disease

Dementia with Lewy bodies (DLB) and Alzheimer's disease (AD) are often associated with depressive symptoms from the prodromal stage. The aim of the present study was to investigate the neuroanatomical correlates of depression in prodromal to mild DLB patients compared with AD patients. Eighty-three DLB patients, 37 AD patients, and 18 healthy volunteers were enrolled in this study. Depression was evaluated with the Mini International Neuropsychiatric Interview (MINI), French version 5.0.0. T1-weighted three-dimensional anatomical images were acquired for all participants. Regression and comparison analyses were conducted using a whole-brain voxel-based morphometry (VBM) approach on the grey matter volume (GMV). DLB patients presented a significantly higher mean MINI score than AD patients (p = 0.004), 30.1% of DLB patients had clinical depression, and 56.6% had a history of depression, while 0% of AD patients had clinical depression and 29.7% had a history of depression. VBM regression analyses revealed negative correlations between the MINI score and the GMV of right prefrontal regions in DLB patients (p < 0.001, uncorrected). Comparison analyses between DLB patients taking and those not taking an antidepressant mainly highlighted a decreased GMV in the bilateral middle/inferior temporal gyrus (p < 0.001, uncorrected) in treated DLB patients. In line with the literature, our behavioral analyses revealed higher depression scores in DLB patients than in AD patients. We also showed that depressive symptoms in DLB are associated with decreased GMV in right prefrontal regions. Treated DLB patients with long-standing depression would be more likely to experience GMV loss in the bilateral middle/inferior temporal cortex. These findings should be taken into account when managing DLB patients.

Neuropsychiatric Symptom Profile in Alzheimer's Disease and Their Relationship With Functional Decline

OBJECTIVE

Understanding the course of individual neuropsychiatric symptoms (NPS) and their relationship with function is important for planning targeted interventions for preventing and delaying functional decline. This study aims to disentangle relative contributions of individual NPS on functional decline.

METHODS

Longitudinal study of 9,358 well-characterized participants with baseline diagnoses of Mild Cognitive Impairment or AD in the National Alzheimer's Coordinating Center Uniform Data Set. Function was measured using the Functional Assessment Questionnaire (FAQ). Clinician judgment of seven common behavioral symptoms were examined simultaneously: apathy-withdrawal, depressed mood, visual or auditory hallucinations, delusions, disinhibition, irritability, and agitation.

RESULTS

Apathy was the most common NPS at baseline (33.7%) and throughout follow-up, endorsed by clinicians in 63.7% of visits. Apathy was the most persistent with 36.7% of participants having clinician-endorsed apathy in ≥50% of their visits. Apathy strongly correlated with faster rate of functional decline. Compared to those who never had apathy, baseline FAQ was worse in those with intermittent or persistent/always apathy (intermittent: estimated coefficient ±SE=1.228±0.210, 95% CI=[0.817, 1.639]; persistent/always: 2.354±0.244 (95% CI=[1.876, 2.832], both p <0.001). Over time, rate of functional decline was faster in those with intermittent and persistent/always apathy (intermittent: 0.454±0.091, 95% CI=[0.276, 0.632]; persistent/always: 0.635±0.102, 95% CI=[0.436, 0.835], both p <0.001). Worse agitation, delusions, and hallucinations also correlated with functional decline, but magnitudes of the estimates were smaller.

CONCLUSION

Individual NPS may be sensitive targets for tracking longitudinal change in function. The study raises awareness of the need for more comprehensive assessment of functional decline in AD patients with noncognitive symptoms.

Spatial-temporal dynamic evolution of lewy body dementia by metabolic PET imaging

PURPOSE

Lewy body dementia (LBD) is a neurodegenerative disease with high heterogeneity and complex pathogenesis. Our study aimed to use disease progression modeling to uncover spatial-temporal dynamic evolution of LBD in vivo, and to explore differential profiles of clinical features, glucose metabolism, and dopaminergic function among different evolution-related subtypes.

METHODS

A total of 123 participants (31 healthy controls and 92 LBD patients) who underwent 18F-FDG PET scans were retrospectively enrolled. 18F-FDG PET-based Subtype and Stage Inference (SuStaIn) model was established to illustrate spatial-temporal evolutionary patterns and categorize relevant subtypes. Then subtypes and stages were further related to clinical features, glucose metabolism, and dopaminergic function of LBD patients.

RESULTS

This 18F-FDG PET imaging-based approach illustrated two distinct patterns of neurodegenerative evolution originating from the neocortex and basal ganglia in LBD and defined them as subtype 1 and subtype 2, respectively. There were obvious differences between subtypes. Compared with subtype 1, subtype 2 exhibited a greater proportion of male patients (P = 0.045) and positive symptoms such as visual hallucinations (P = 0.033) and fluctuating cognitions (P = 0.033). Cognitive impairment, metabolic abnormalities, dopaminergic dysfunction and progression were all more severe in subtype 2 (all P < 0.05). In addition, a strong association was observed between SuStaIn subtypes and two clinical phenotypes (Parkinson's disease dementia and dementia with Lewy bodies) (P = 0.005).

CONCLUSIONS

Our findings based on 18F-FDG PET and data-driven model illustrated spatial-temporal dynamic evolution of LBD and categorized novel subtypes with different evolutionary patterns, clinical and imaging features in vivo. The evolution-related subtypes are associated with LBD clinical phenotypes, which supports the perspective of existence of distinct entities in LBD spectrum.

Investigating the feasibility of 18F-flortaucipir PET imaging in the antemortem diagnosis of primary age-related tauopathy (PART): An observational imaging-pathological study

INTRODUCTION

Primary age-related tauopathy (PART) is characterized by neurofibrillary tangles and minimal β-amyloid deposition, diagnosed postmortem. This study investigates 18F-flortaucipir (FTP) PET imaging for antemortem PART diagnosis.

METHODS

We analyzed FTP PET scans from 50 autopsy-confirmed PART and 13 control subjects. Temporal lobe uptake was assessed both qualitatively and quantitatively. Demographic and clinicopathological characteristics and voxel-level uptake using SPM12 were compared between FTP-positive and FTP-negative cases. Intra-reader reproducibility was evaluated with Krippendorff's alpha.

RESULTS

Minimal/mild and moderate FTP uptake was seen in 32% of PART cases and 62% of controls, primarily in the left inferior temporal lobe. No demographic or clinicopathological differences were found between FTP-positive and FTP-negative cases. High intra-reader reproducibility (α = 0.83) was noted.

DISCUSSION

FTP PET imaging did not show a specific uptake pattern for PART diagnosis, indicating that in vivo PART identification using FTP PET is challenging. Similar uptake in controls suggests non-specific uptake in PART.

HIGHLIGHTS

18F-flortaucipir (FTP) PET scans were analyzed for diagnosing PART antemortem. 32% of PART cases had minimal/mild FTP uptake in the left inferior temporal lobe. Similar to PART FTP uptake was found in 62% of control subjects. No specific uptake pattern was found, challenging in vivo PART diagnosis.

The updated prevalence and risk factors of dementia in old adults in China: A cross-sectional study

BACKGROUND

The continuously increasing aging population and life expectancy have led to an inconsistent and underestimated dementia prevalence in China. An updated epidemiologic study is urgently needed.

OBJECTIVE

To update the prevalence rate and risk factors of dementia in China.

METHODS

For this national cross-sectional study, 20,438 participants aged ≥65 from 28 communities and 56 villages from 14 centers were recruited using a multistage cluster sampling design between May 2019 and December 2019. Participants were assessed with a series of clinical and neuropsychological measurements. The prevalence rates of dementia, Alzheimer's disease (AD), and vascular dementia (VaD), as well as the risk factors, were calculated using multivariate-adjusted models.

RESULTS

The crude prevalence rates were 9.1% (95% CI, 8.7%-9.5%) for dementia, 6.0% (95% CI, 5.7%-6.3%) for AD, 1.4% (95% CI, 1.2%-1.5%) for VaD, and 1.8% (95% CI, 1.6%-2.0%) for other dementias in a population aged ≥65 years. The overall sex- and age-standardized prevalence was 8.8%. Apart from VaD, the prevalence rates of dementia and AD were higher in females than males (10.3% versus 7.7%, respectively). Moreover, the prevalence rates of dementia and AD increased significantly with age. Being unmarried and having fewer social activities increased the risks of dementia and main subtypes. Risk factors were not exactly the same for participants with AD and VaD.

CONCLUSIONS

The prevalence of dementia is increased and almost comparable with that of developed countries for individuals aged ≥65 years. These findings may serve as new evidence for government interventions in aging.

Multisite Skin Biopsies vs Cerebrospinal Fluid for Prion Seeding Activity in the Diagnosis of Prion Diseases

Importance

Recent studies have revealed that autopsy skin samples from cadavers with prion diseases (PRDs) exhibited a positive prion seeding activity similar to cerebrospinal fluid (CSF). It is worthwhile to validate the findings with a large number of biopsy skin samples and compare the clinical value of prion seeding activity between skin biopsies and concurrent CSF specimens.

Objective

To compare the prion seeding activity of skin biopsies and CSF samples and to determine the effectiveness of combination of the skin biopsies from multiple sites and numerous dilutions on the diagnosis for various types of PRDs.

Design, Setting, and Participants

In the exploratory cohort, patients were enrolled from September 15, 2021, to December 15, 2023, and were followed up every 3 months until April 2024. The confirmatory cohort enrolled patients from December 16, 2023, to June 31, 2024. The exploratory cohort was conducted at a single center, the neurology department at Xuanwu Hospital. The confirmatory cohort was a multicenter study involving 4 hospitals in China. Participants included those diagnosed with probable sporadic Creutzfeldt-Jakob disease or genetically confirmed PRDs. Patients with uncertain diagnoses or those lost to follow-up were excluded. All patients with PRDs underwent skin sampling at 3 sites (the near-ear area, upper arm, lower back, and inner thigh), and a portion of them had CSF samples taken simultaneously. In the confirmatory cohort, a single skin biopsy site and CSF samples were simultaneously collected from a portion of patients with PRDs.

Exposures

The skin and CSF prion seeding activity was assessed using the real-time quaking-induced conversion (RT-QUIC) assay, with rHaPrP90-231, a Syrian hamster recombinant prion protein, as the substrate. In the exploratory cohort, skin samples were tested at dilutions of 10-2 through 10-4. In the confirmatory cohort, skin samples were tested at a dilution of 10-2. A total of four 15-μL wells of CSF were used in the RT-QUIC assay.

Main Outcomes and Measures

Correlations between RT-QUIC results from the skin and CSF and the final diagnosis of enrolled patients.

Results

In the exploratory cohort, the study included 101 patients (mean [SD] age, 60.9 [10.2] years; 63 female [62.4%]) with PRD and 23 patients (mean [SD] age, 63.4 [9.1] years; 13 female [56.5%]) without PRD. A total of 94 patients had CSF samples taken simultaneously with the skin biopsy samples. In the confirmatory cohort, a single skin biopsy site and CSF sample were taken simultaneously in 43 patients with PRDs. Using an experimental condition of 10-2 dilution, the RT-QUIC positive rates of skin samples from different sites were comparable with those of the CSF (skin: 18 of 26 [69.2%] to 74 of 93 [79.6%] vs CSF: 71 of 94 [75.5%]). When tested at 3 different dilutions, all skin sample positivity rates increased to over 80.0% (79 of 93 for the near-ear area, 21 of 26 for the upper arm, 77 of 92 for the lower back, and 78 of 92 for the inner thigh). Combining samples from skin sites near the ear, inner thigh, and lower back in pairs yielded positivity rates exceeding 92.1% (93 of 101), significantly higher than CSF alone (71 of 94 [75.5%]; P =.002). When all skin sample sites were combined and tested at 3 dilution concentrations for RT-QUIC, the sensitivity reached 95.0% (96 of 101). In the confirmatory cohort, the RT-QUIC positive rate of a single skin biopsy sample was slightly higher than that of the CSF (34 of 43 [79.1%] vs 31 of 43 [72.1%]; P = .45).

Conclusions and Relevance

Results of this diagnostic study suggest that the sensitivity of an RT-QUIC analysis of a combination of 2 or more skin sites was superior to that of CSF in diagnosing PRDs.

Post-mortem neuropathology of idiopathic rapid eye movement sleep behaviour disorder: a case series

BACKGROUND

Idiopathic rapid eye movement (REM) sleep behaviour disorder (IRBD) is thought to be an early stage of α-synuclein-related neurodegenerative diseases. Nevertheless, the definitive identification of its biological substrate can be determined only by post-mortem neuropathology. We aimed to describe the post-mortem neuropathology of individuals with IRBD who developed or did not develop a neurodegenerative disease before death.

METHODS

In this case series at the Hospital Clinic de Barcelona, Barcelona, Spain, we examined post-mortem brain tissue and spinal cords from individuals diagnosed with IRBD by video polysomnography who became donors to the Neurological Tissue Bank between May 28, 2005, and March 23, 2023. We performed post-mortem neuropathology to assess the presence and distribution of neuronal loss, gliosis, and protein aggregates using antibodies against α-synuclein, amyloid β, phosphorylated tau, three-repeat and four-repeat tau isoforms, and TDP-43. Comparative statistical analyses were not done because of the small sample size, but differences observed across the nuclei and brain structures were described.

FINDINGS

The brains and spinal cords of 20 individuals with IRBD were examined (19 [95%] men, one [5%] woman). Their clinical antemortem diagnoses were of IRBD without any other neurological disorder in three (15%), Parkinson's disease without dementia in two (10%), Parkinson's disease dementia (PDD) in three (15%), and dementia with Lewy bodies (DLB) in 12 (60%) individuals. Post-mortem neuropathological diagnoses were Lewy body disease in 19 (95%) and multiple system atrophy (MSA) in one (5%). All participants with Lewy body disease and MSA showed neuronal loss, gliosis, and α-synuclein deposits in neurons and astrocytes. In all participants, α-synuclein was found in the structures that regulate REM sleep atonia (eg, subcoeruleus nucleus, gigantocellular reticular nucleus, laterodorsal tegmentum, and amygdala). Coexistent pathologies were found in all participants, including Alzheimer's disease pathology (amyloid β plaques and neurofibrillary tangles) in 14 (70%), ageing-related tau astrogliopathy in 12 (60%), cerebral amyloid angiopathy in 11 (55%), argyrophilic grain disease in four (20%), limbic-predominant age-related TDP-43 encephalopathy in four (20%), and early changes indicative of progressive supranuclear palsy in three (15%). In individuals with IRBD without any other neurological disorder and in those who developed Parkinson's disease without dementia, α-synuclein was found in the brainstem and limbic system and rarely in the cortex, whereas coexisting proteinopathies were few and showed mild pathological burden. In contrast, in individuals who developed PDD or DLB, α-synuclein had diffuse distribution in the brainstem, limbic system, and cortex, and multiple comorbid pathologies were common, particularly those related to Alzheimer's disease.

INTERPRETATION

Although limited by a relatively small sample size, our observations provide strong neuropathological evidence that IRBD is an early stage of α-synuclein-related neurodegenerative disease. Concomitant pathologies are frequent and their role remains to be clarified: some might have contributed to the development of dementia, but some might be age-related changes. Our findings could inform the design of clinical trials of compounds that target specific pathological proteins (eg, α-synuclein and amyloid β) in people with IRBD.

FUNDING

Fundación BBVA-Hospital Clínic de Barcelona.

A General Neurologist's Practical Diagnostic Algorithm for Atypical Parkinsonian Disorders: A Consensus Statement

Purpose of Review

The most common four neurodegenerative atypical parkinsonian disorders (APDs) are progressive supranuclear palsy (PSP), multiple system atrophy (MSA), corticobasal syndrome (CBS), and dementia with Lewy bodies (DLB). Their formal diagnostic criteria often require subspecialty experience to implement as designed and all require excluding competing diagnoses without clearly specifying how to do that. Validated diagnostic criteria are not available at all for many of the other common APDs, including normal pressure hydrocephalus (NPH), vascular parkinsonism (VP), or drug-induced parkinsonism (DIP). APDs also include conditions of structural, genetic, vascular, toxic/metabolic, infectious, and autoimmune origin. Their differential diagnosis can be challenging early in the course, if the presentation is atypical, or if a rare or non-neurodegenerative condition is present. This review equips community general neurologists to make an early provisional diagnosis before, or in place of, referral to a tertiary center. Early diagnosis would allay diagnostic uncertainty, allow prompt symptomatic management, provide disease-specific information and support resources, avoid further pointless testing and treatments, and create the possibility of trial referral.

Recent Findings

We address 64 APDs using one over-arching flow diagram and a series of detailed tables. Most instances of APDs can be diagnosed with a careful history and neurological exam, along with a non-contrast brain MRI. Additional diagnostic tests are rarely needed but are delineated where applicable. Our diagnostic algorithm encourages referral to a tertiary center whenever the general neurologist feels it would be in the patient's best interest. Our algorithm emphasizes that the diagnosis of APDs is an iterative process, refined with the appearance of new diagnostic features, availability of new technology, and advances in scientific understanding of the disorders. Clinicians' proposals for all diagnostic tests for the APDs, including repeat visits, should be discussed with patients and their families to ensure that the potential information to be gained aligns with their larger clinical goals.

Summary

We designed this differential diagnostic algorithm for the APDs to enhance general neurologists' diagnostic skills and confidence and to help them address the less common or more ambiguous cases.

Astrocytic Ca2+ activation by chemogenetics mitigates the effect of kainic acid-induced excitotoxicity on the hippocampus

Astrocytes play a multifaceted role regulating brain glucose metabolism, ion homeostasis, neurotransmitters clearance, and water dynamics being essential in supporting synaptic function. Under different pathological conditions such as brain stroke, epilepsy, and neurodegenerative disorders, excitotoxicity plays a crucial role, however, the contribution of astrocytic activity in protecting neurons from excitotoxicity-induced damage is yet to be fully understood. In this work, we evaluated the effect of astrocytic activation by Designer Receptors Exclusively Activated by Designer Drugs (DREADDs) on brain glucose metabolism in wild-type (WT) mice, and we investigated the effects of sustained astrocyte activation following an insult induced by intrahippocampal (iHPC) kainic acid (KA) injection using 2-deoxy-2-[18F]-fluoro-D-glucose (18F-FDG) positron emission tomography (PET) imaging, along with behavioral test, nuclear magnetic resonance (NMR) spectroscopy and histochemistry. Astrocytic Ca2+ activation increased the 18F-FDG uptake, but this effect was not found when the study was performed in knock out mice for type-2 inositol 1,4,5-trisphosphate receptor (Ip3r2-/-) nor in floxed mice to abolish glucose transporter 1 (GLUT1) expression in hippocampal astrocytes (GLUT1ΔGFAP). Sustained astrocyte activation after KA injection reversed the brain glucose hypometabolism, restored hippocampal function, prevented neuronal death, and increased hippocampal GABA levels. The findings of our study indicate that astrocytic GLUT1 function is crucial for regulating brain glucose metabolism. Astrocytic Ca2+ activation has been shown to promote adaptive changes that significantly contribute to mitigating the effects of KA-induced damage. This evidence suggests a protective role of activated astrocytes against KA-induced excitotoxicity.

Presumed aetiologies and clinical outcomes of non-lesional late-onset epilepsy

BACKGROUND AND PURPOSE

Our objective was to define phenotypes of non-lesional late-onset epilepsy (NLLOE) depending on its presumed aetiology and to determine their seizure and cognitive outcomes at 12 months.

METHODS

In all, 146 newly diagnosed NLLOE patients, >50 years old, were prospectively included and categorized by four presumed aetiological subtypes: neurodegenerative subtype (patients with a diagnosis of neurodegenerative disease) (n = 31), microvascular subtype (patients with three or more cardiovascular risk factors and two or more vascular lesions on MRI) (n = 39), inflammatory subtype (patient meeting international criteria for encephalitis) (n = 9) and unlabelled subtype (all individuals who did not meet the criteria for other subtypes) (n = 67). Cognitive outcome was determined by comparing for each patient the proportion of preserved/altered scores between initial and second neuropsychological assessment.

RESULTS

The neurodegenerative subtype had the most severe cognitive profile at diagnosis with cognitive complaint dating back several years. The microvascular subtype was mainly evaluated through the neurovascular emergency pathway. Their seizures were characterized by transient phasic disorders. Inflammatory subtype patients were the youngest. They presented an acute epilepsy onset with high rate of focal status epilepticus. The unlabelled subtype presented fewer comorbidities with fewer lesions on brain imaging. The neurodegenerative subtype had the worst seizure and cognitive outcomes. In other groups, seizure control was good under antiseizure medication (94.7% seizure-free) and cognitive performance was stabilized or even improved.

CONCLUSION

This new characterization of NLLOE phenotypes raises questions regarding the current International League Against Epilepsy aetiological classification which does not individualize neurodegenerative and microvascular aetiology per se.

Neuropathologic findings in a patient with hemiparkinsonism and hemiatrophy syndrome

The first postmortem neuropathological findings of a hemiparkinsonism and hemiatrophy (HPHA) patient are presented. A 50-year-old man developed resting tremors affecting the right hand and leg, followed by mild clumsiness of the right hand. On examination, he exhibited muscle atrophy of the right leg extremity, accompanied by right-sided parkinsonism. Brain magnetic resonance imaging was normal. Based on the clinical and radiological findings, HPHA syndrome was diagnosed, showing a good response to L-DOPA. He gradually developed muscular atrophy of the right distal upper extremity. Thirteen years after the onset of the disease, left-sided parkinsonism appeared. The patient died of Trousseau's syndrome associated with a rapidly emerging pancreatic tumor. The total duration of the disease was 14 years. Neuropathologically, the substantia nigra showed markedly left-predominant neuronal loss, along with almost symmetrical Lewy body (LB) pathology. These findings indicated that the patient originally had fewer neurons in the left substantia nigra than in the right, probably caused by congenital or childhood cerebral injury, followed by the development of unilateral parkinsonism due to the progression of LB pathology. Despite our extensive neuropathological analysis, we could not specify the etiology or anatomical substrate responsible for the development of right upper and lower extremity atrophy. Further clinicopathological studies are needed to elucidate the pathoanatomical areas causing hemiparkinsonism and hemiatrophy.

Resting-state EEG spectral and fractal features in dementia with Lewy bodies with and without visual hallucinations

OBJECTIVE

Complex visual hallucinations (VH) are a core feature of dementia with Lewy bodies (DLB), though they may not occur in all patients. Power spectral density (PSD) analysis of resting-state EEG (rs-EEG) shows associations between some frequency bands (e.g., theta), individual alpha frequency (IAF) and VH. However, new tools that improve early differential diagnosis and symptom-based stratification with higher sensitivity and specificity, even within the DLB population, are desirable. We aimed to assess differences in rs-EEG data between DLB patients with VH (DLB-VH+) and without VH (DLB-VH-), comparing innovative non-linear approaches with more traditional linear ones.

METHODS

We retrospectively analyzed rs-EEG recordings of DLB-VH+, DLB-VH-, Alzheimer's disease patients and age-matched healthy controls. EEG was analyzed using the nonlinear Higuchi's Fractal Dimension (FD) measure, and the results were compared with those of entropy and standard linear methods based on PSD and IAF.

RESULTS

Only the FD measure could discriminate between DLB-VH+ and DLB-VH-.

CONCLUSIONS

In conclusion, rs-EEG differences between DLB-VH+ and DLB-VH- are better characterized by FD analysis than by a more traditional power spectrum approach.

SIGNIFICANCE

This suggests that the presence of complex VH is associated with less complex brain dynamics at rest, as reflected by the FD measure.

Cognitive Impact of β-Amyloid Load in the Rapid Eye Movement Sleep Behavior Disorder-Lewy Body Disease Continuum

BACKGROUND

Rapid eye movement sleep behavior disorder (RBD) is linked to the diffuse-malignant subtype and higher cognitive burden in Lewy body disease (LBD).

OBJECTIVE

This study explores brain β-amyloid deposition and its association with cognitive decline across the RBD-LBD continuum.

METHODS

Patients with isolated RBD (iRBD), Parkinson's disease with probable RBD (PDRBD), and dementia with Lewy bodies with probable RBD (DLBRBD) underwent 18F-florbetaben positron emission tomography, 3T magnetic resonance imaging scans, and comprehensive neuropsychological assessments. Subjects were categorized as cognitively normal (NC), mild cognitive impairment (MCI), or dementia. Global and regional standardized uptake value ratios (SUVR) were estimated in predefined cognitive volumes of interest (VOI) derived from voxel-wise comparison analysis among the cognitive groups, namely the prefrontal, parietal, precentral cortices, lingual gyrus, and supplementary motor area. Generalized linear models assessed the relationship between 18F-florbetaben SUVRs and neuropsychological testing, adjusting for age and sex. Subgroup analysis focused on the polysomnography-confirmed iRBD-continuum subset (n = 41) encompassing phenoconverters and nonconverters in our prospective iRBD cohort.

RESULTS

Eighty-six subjects were classified as follows: 14 NC, 54 MCI, and 18 dementia. The proportion of positive β-amyloid scans increased with advanced cognitive stages (P = 0.038). β-Amyloid signals in cognitive VOIs were elevated in subgroups showing impairment in Trail-Making Test B (TMT-B). A linear association between TMT-B z score and global cortical β-amyloid levels was observed in the iRBD-continuum subset (P = 0.013).

CONCLUSION

Cortical β-amyloid accumulates with declines in executive function within the RBD-LBD continuum. TMT-B performance may be a useful marker associating with β-amyloid load, particularly in the iRBD population. © 2024 The Author(s). Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Evaluating Electroconvulsive Therapy for Dementia With Lewy Bodies, Including the Prodromal Stage: A Retrospective Study on Safety and Efficacy

OBJECTIVES

Managing symptoms, notably psychiatric symptoms, in dementia with Lewy bodies (DLB) is complex, affecting both patients and caregivers. People with DLB often react poorly to antipsychotics, limiting treatment options. Although electroconvulsive therapy (ECT)'s potential for DLB is acknowledged, evidence is scarce owing to limited studies. This study investigated ECT's effectiveness and safety for DLB and prodromal DLB with antecedent psychiatric symptoms.

METHODS

This retrospective study investigated people with DLB (N = 12) and mild cognitive impairment (MCI) with LB (N = 13), a prodromal form of DLB, who underwent ECT for psychiatric symptoms and had abnormal findings confirmed using dopamine transporter single-photon emission computed tomography and 123I-metaiodobenzylguanidine myocardial scintigraphy. We reviewed these patients' medical records and determined the severity of psychotic symptoms before and 1 week after the final ECT session with the Clinical Global Impressions Severity Scale (CGI-S). Improvement in psychotic symptoms was evaluated approximately 1 week after the final ECT session using the CGI Improvement Scale (CGI-I). Additionally, we assessed cognitive function and dementia severity before and after ECT, as well as any adverse events caused by ECT.

RESULTS

ECT significantly improved psychiatric symptoms, as assessed using the CGI-S, with CGI-I reports in the order of 60% "very much improved," 20% "much improved," 16% "minimally improved," and 4% "no change." Parkinsonism improved (Hoehn and Yahr: 1.76 ± 1.2 before vs. 1.04 ± 0.7 after, p < 0.001) as did dementia severity (Clinical Dementia Rating, p = 0.037). Adverse events included delirium in 24% of patients and amnesia in 4% of patients. ECT did not worsen cognitive function.

CONCLUSIONS

ECT for DLB and MCI with LB with antecedent psychiatric symptoms appears safe and effective in managing psychiatric symptoms and Parkinsonism. Further large-scale multicenter studies are warranted to conclusively establish its effectiveness and safety.

Effect of GBA1 Mutations and APOE Polymorphisms on Survival and Progression Among Ashkenazi Jews with Dementia with Lewy Bodies

BACKGROUND

Glucocerebrosidase 1 (GBA1) mutations are associated with reduced survival in Parkinson's disease but their effect on survival in dementia with Lewy bodies (DLB) is unclear.

OBJECTIVE

To assess the impact of GBA1 mutations on survival among Ashkenazi Jews with DLB, while controlling for APOE status.

METHODS

One hundred and forty participants from Tel Aviv Medical Center, Israel were genotyped for GBA1 mutations and APOE polymorphisms. Survival rates and follow-up cognitive screening scores were analyzed.

RESULTS

GBA1 mutation carriers had a two-fold increased risk of death (HR = 1.999), while APOE status did not independently affect survival. In a subset of patients with available clinical data (N = 63), carriers of the APOE ε4 allele showed faster cognitive deterioration, while GBA1 mutation carriers also declined more rapidly albeit not significantly.

CONCLUSION

Understanding the genetic effects on survival and progression is crucial for patient counseling and inclusion in clinical trials.

Lewy Body Dementia

OBJECTIVE

Lewy body dementia (LBD) is an umbrella term describing two closely related conditions: Parkinson disease dementia (PDD) and dementia with Lewy bodies (DLB). LBD is the second most common cause of neurodegenerative dementia but is often underrecognized in clinical practice. This review covers the key epidemiologic, clinical, cognitive, behavioral, and biomarker features of LBD and discusses current treatment options.

LATEST DEVELOPMENTS

Indicative biomarkers of LBD improve the ability to make a diagnosis and include single-photon emission computed tomography (SPECT) of the dopamine system (brain) and the noradrenergic system (cardiac), and polysomnography. α-Synuclein-specific biomarkers in spinal fluid, skin, plasma, and brain imaging are in active development with some available for clinical use. Prodromal stages of PDD and DLB have been contextualized, and diagnostic criteria have been published. An emerging theme is whether an integrated staging system focusing on protein aggregation, rather than clinical symptoms, may advance research efforts.

ESSENTIAL POINTS

LBD is a common cause of cognitive impairment in older adults but is often subject to significant delays in diagnosis and treatment, increasing the burden on patients and family care partners. Understanding key features of disease and the use of biomarkers will improve recognition. Earlier detection may also facilitate the development of new therapeutics and enrollment in clinical trials.

Sensitivity and specificity of a seed amplification assay for diagnosis of multiple system atrophy: a multicentre cohort study

BACKGROUND

The pathological hallmarks of multiple system atrophy and Parkinson's disease are, respectively, misfolded-α-synuclein-laden glial cytoplasmic inclusions and Lewy bodies. CSF-soluble misfolded α-synuclein aggregates (seeds) are readily detected in people with Parkinson's disease by α-synuclein seed amplification assay (synSAA), but identification of seeds associated with multiple system atrophy for diagnostic purposes has proven elusive. We aimed to assess whether a novel synSAA could reliably distinguish seeds from Lewy bodies and glial cytoplasmic inclusions.

METHODS

In this multicentre cohort study, a novel synSAA that multiplies and detects seeds by fluorescence was used to analyse masked CSF and brain samples from participants with either clinically diagnosed or pathology-confirmed multiple system atrophy, Parkinson's disease, dementia with Lewy bodies, isolated rapid eye movement sleep behaviour disorder (IRBD), disorders that were not synucleinopathies, or healthy controls. Participants were from eight available cohorts from seven medical centres in four countries: New York Brain Bank, New York, USA (NYBB); University of Pennsylvania, Philadelphia, PA, USA (UPENN); Paracelsus-Elena-Klinik, Kassel, Germany (DeNoPa and KAMSA); Hospital Clinic Barcelona, Spain (BARMSA); Universität Tübingen, Tübingen, Germany (EKUT); Göteborgs Universitet, Göteborgs, Sweden (UGOT); and Karolinska Institutet, Stockholm, Sweden (KIMSA). Clinical cohorts were classified for expected diagnostic accuracy as either research (longitudinal follow-up visits) or real-life (single visit). Sensitivity and specificity were estimated according to pathological (gold standard) and clinical (reference standard) diagnoses.

FINDINGS

In 23 brain samples (from the NYBB cohort), those containing Lewy bodies were synSAA-positive and produced high fluorescence amplification patterns (defined as type 1); those containing glial cytoplasmic inclusions were synSAA-positive and produced intermediate fluorescence (defined as type 2); and those without α-synuclein pathology produced below-threshold fluorescence and were synSAA-negative. In 21 pathology-confirmed CSF samples (from the UPENN cohort), those with Lewy bodies were synSAA-positive type 1; those with glial cytoplasmic inclusions were synSAA-positive type 2; and those with four-repeat tauopathy were synSAA-negative. In the DeNoPa research cohort (which had no samples from people with multiple system atrophy), the novel synSAA had sensitivities of 95% (95% CI 88-99) for 80 participants with Parkinson's disease and 95% (76-100) for 21 participants with IRBD, and a specificity of 95% (86-99) for 60 healthy controls. Overall (combining BARMSA, EKUT, KAMSA, UGOT, and KIMSA cohorts that were enriched for cases of multiple system atrophy), the novel synSAA had 87% sensitivity for multiple system atrophy (95% CI 80-93) and specificity for type 2 seeds was 77% (67-85). For participants with multiple system atrophy just in research cohorts (BARMSA and EKUT), the novel synSAA had a sensitivity of 84% (95% CI 71-92) and a specificity for type 2 seeds of 87% (74-95), whereas cases from real-life cohorts (KAMSA, KIMSA, and UGOT) had a sensitivity of 91% (95% CI 80-97) but a decreased specificity for type 2 seeds of 68% (53-81).

INTERPRETATION

The novel synSAA produced amplification patterns that enabled the identification of underlying α-synuclein pathology, showing two levels of fluorescence that corresponded with different pathological hallmarks of synucleinopathy. The synSAA might be useful for early diagnosis of synucleinopathies in clinical trials, and potentially for clinical use, but additional formal validation work is needed.

FUNDING

Michael J Fox Foundation for Parkinson's Research, Amprion.