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

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.

Eating problems in people with dementia with Lewy bodies: Associations with various symptoms and the physician's understanding

OBJECTIVES

Eating problems frequently occur in people with dementia with Lewy bodies (DLB), but few studies have investigated the clinical background of this phenomenon. This study examined the relationship between eating problems and various symptoms of DLB and the relation between the treatment needs for DLB people with eating problems and the understanding of their eating problems by caregivers and physicians.

DESIGN, MEASUREMENTS, AND PARTICIPANTS

This was a subanalysis of a cross-sectional, questionnaire-based survey study. Two hundred sixty-one subjects with DLB were divided into subjects with or without eating problems. Logistic or linear regression analysis was used to investigate the factors influencing eating problems. The treatment needs of DLB people for their eating problems and the understanding of these needs by caregivers and physicians were calculated as participant-caregiver and participant-physician kappa coefficient.

RESULTS

Of the 261 participants, 27% suffered from eating problems. The presence of eating problems in participants with DLB was related to depression (p = 0.01, OR : 2.19, 95% CI: 1.23-3.91) and apathy (p = 0.01, OR 2.15, 95% CI: 1.20-3.87), while the worsening of eating problems was related to dysphagia (β = 0.24, p = 0.03), apathy (β = 0.23, p = 0.05), and nighttime behavior (β = 0.24, p = 0.04). The participant-physician kappa coefficient for physician understanding of constipation, weight loss, dysphagia, weight gain, and increase in appetite was significantly lower than the corresponding participant-caregiver kappa coefficient (p-value of five symptoms < 0.01).

CONCLUSIONS

Physicians need to pay more attention to eating problems and their neuropsychiatric background in the long-term support and management of DLB subjects.

Cholinergic dysfunction in isolated rapid eye movement sleep behaviour disorder links to impending phenoconversion

BACKGROUND AND PURPOSE

Most patients with isolated rapid eye movement sleep behaviour disorder (iRBD) progress to a parkinsonian alpha-synucleinopathy. However, time to phenoconversion shows great variation. The aim of this study was to investigate whether cholinergic and dopaminergic dysfunction in iRBD patients was associated with impending phenoconversion.

METHODS

Twenty-one polysomnography-confirmed iRBD patients underwent baseline 11C-donepezil and 6-Fluoro-(18F)-l-3,4-dihydroxyphenylalanine (18F-DOPA) positron emission tomography (PET). Potential phenoconversion was monitored for up to 8 years. PET images were analysed according to patients' diagnoses after 3 and 8 years using linear regression. Time-to-event analysis was made with Cox regression, dividing patients into low and high tracer uptake groups.

RESULTS

Follow-up was accomplished in 17 patients. Eight patients progressed to either Parkinson's disease (n = 4) or dementia with Lewy bodies (n = 4), while nine remained non-phenoconverters. Compared with non-phenoconverters, 8-year phenoconverters had lower mean 11C-donepezil uptake in the parietal (p = 0.032) and frontal cortex (p = 0.042), whereas mean 11C-donepezil uptake in 3-year phenoconverters was lower in the parietal cortex (p = 0.005), frontal cortex (p = 0.025), thalamus (p = 0.043) and putamen (p = 0.049). Phenoconverters within 3 years and 8 years had lower 18F-DOPA uptake in the putamen (p < 0.001). iRBD patients with low parietal 11C-donepezil uptake had a 13.46 (95% confidence interval 1.42;127.21) times higher rate of phenoconversion compared with those with higher uptake (p = 0.023). iRBD patients with low 18F-DOPA uptake in the most affected putamen were all phenoconverters with higher rate of phenoconversion (p = 0.0002).

CONCLUSIONS

These findings suggest that cortical cholinergic dysfunction, particularly within the parietal cortex, could be a biomarker candidate for predicting short-term phenoconversion in iRBD patients. This study aligns with previous reports suggesting dopaminergic dysfunction is associated with forthcoming phenoconversion.

Genetics and Neuropathology of Neurodegenerative Dementias

OBJECTIVE

This article provides an overview of the current understanding of the genetic and pathologic features of neurodegenerative dementias, with an emphasis on Alzheimer disease and related dementias.

LATEST DEVELOPMENTS

In recent years, there has been substantial progress in genetic research, contributing significant knowledge to our understanding of the molecular risk factors involved in neurodegenerative dementia syndromes. Several genes have been linked to monogenic forms of dementia (eg, APP, PSEN1, PSEN2, SNCA, GRN, C9orf72, MAPT) and an even larger number of genetic variants are known to influence susceptibility for developing dementia. As anti-amyloid therapies for patients with early-stage Alzheimer disease have entered the clinical arena, screening for the apolipoprotein E ε4 high-risk allele has come into focus, emphasizing the importance of genetic counseling. Similarly, advances in the pathologic classifications of neurodegenerative dementia syndromes and molecular pathology highlight their heterogeneity and overlapping features and provide insights into the pathogenesis of these conditions.

ESSENTIAL POINTS

Recent progress in neurogenetics and molecular pathology has improved our understanding of the complex pathogenetic changes associated with neurodegenerative dementias, facilitating improved disease modeling, enhanced diagnostics, and individualized counseling. The hope is that this knowledge will ultimately pave the way for the development of novel therapeutics.

Intrasubject reproducibility of supine norepinephrine plasma concentrations in patients with cardiovascular sympathetic failure

BACKGROUND

Plasma levels of the catecholamine norepinephrine (NE) has emerged as a useful tool to help differentiate pre- and post-ganglionic disorders in patients with cardiovascular autonomic failure (AF). However, data on intrasubject reliability in individuals with these conditions are limited. We evaluated the intrasubject reproducibility of supine plasma NE levels drawn across two consecutive time points under controlled conditions during head-up table testing in a large cohort of patients with alpha-synucleinopathies and both pre- and post-ganglionic cardiovascular AF.

METHODS

Antecubital venous blood drawn via an indwelling cannula with the subject supine was assayed for plasma level of catecholamines. We collected two consecutive samples, the first after 20 min of supine rest (NE1) and the second 5 min later (NE2), from a group of 279 participants including 57 with Parkinson's disease/Lewy body dementia (44 M; 65.5 ± 11.1 y), 131 with multiple system atrophy (81 M; 63.2 ± 8.5 y), 41 with pure autonomic failure (25 M, 65.1 ± 9.3 y), and 50 healthy controls (27 M; 46.7 ± 19.4 y).

RESULTS

We found no difference between NE1 and NE2 (p = 0.645), with a mean intrasubject reproducibility (NE maximum - NE minimum) × 100 / NE maximum) of 11.5 % ± 10.64. This finding was confirmed when controlling for diagnosis (p = 0.669), gender (p = 0.493), age (p = 0.865), disease duration (p = 0.596) or considering all factors together (p = 0.527).

CONCLUSIONS

We found excellent test-retest reliability of consecutive supine NE measurements in patients with alpha-synucleinopathies and cardiovascular AF, independent of age, gender and disease duration. This lends evidence to support the use of a single supine NE measurement in these conditions.

Diagnosing Alzheimer Disease

OBJECTIVE

This article reviews the current understanding of Alzheimer disease (AD), including the natural history, common risk factors, and expected progression of AD neuropathologic change so that neurologists can apply this knowledge to identify patients with symptoms, signs, and findings on common diagnostic tests consistent with AD.

LATEST DEVELOPMENTS

The advent of potential disease-modifying therapies emphasizes the need to develop and deploy a practical and efficient approach to diagnose patients with cognitive impairment due to AD.

ESSENTIAL POINTS

The accumulation and spread of cerebral amyloid plaques and tau tangles in patients with AD leads to synaptic dysfunction, neuronal loss, and the eventual emergence and progression of cognitive impairment. A pragmatic and organized approach is needed to recognize patients with symptomatic AD in clinical practice, stage the level of impairment, confirm the clinical diagnosis, and apply this information to advance therapeutic decision making.

Perceptual constancy of pareidolias across paper and digital testing formats in neurodegenerative diseases

Pareidolias refer to visual perceptual deficits where ambiguous shapes take on meaningful appearances. In neurodegenerative diseases, pareidolias are examined via a paper-based neuropsychological tool called the noise pareidolia test. In this study, we present initial findings regarding the utilization of pareidolia test on a digital format to analyze variations between paper-based and digital testing approaches. We performed our experiments on healthy controls, patients diagnosed with Alzheimer's disease (AD), Dementia with Lewy body disease (DLB) and Parkinson's disease (PD). Baseline MMSE assessments were conducted, followed by pareidolia testing using both paper-based tools and smartphones. Bland-Altman analysis was performed to evaluate the agreement between the two methods. We found that the illusionary phenomenon of pareidolia is consistent across paper and digital modalities of testing; that perceptual constancy is maintained across patient groups despite variations in image sizes; and pareidolic misperceptions, to some extent, are stabilized on a digital format. Our findings demonstrate a practical way of testing pareidolias on smartphones without compromising on the functionality of the test.

Use of Artificial Intelligence in Imaging Dementia

Alzheimer's disease is the most common cause of dementia in the elderly population (aged 65 years and over), followed by vascular dementia, Lewy body dementia, and rare types of neurodegenerative diseases, including frontotemporal dementia. There is an unmet need to improve diagnosis and prognosis for patients with dementia, as cycles of misdiagnosis and diagnostic delays are challenging scenarios in neurodegenerative diseases. Neuroimaging is routinely used in clinical practice to support the diagnosis of neurodegenerative diseases. Clinical neuroimaging is amenable to errors owing to varying human judgement as the imaging data are complex and multidimensional. Artificial intelligence algorithms (machine learning and deep learning) enable automation of neuroimaging interpretation and may reduce potential bias and ameliorate clinical decision-making. Graph convolutional network-based frameworks implicitly provide multimodal sparse interpretability to support the detection of Alzheimer's disease and its prodromal stage, mild cognitive impairment. In patients with amyloid-related imaging abnormalities, radiologists had significantly better detection performances with both ARIA-E (sensitivity higher in the assisted/deep learning method [87%] compared to unassisted [71%]) and for ARIA-H signs (sensitivity was higher in assisted [79%] compared to unassisted [69%]). A convolutional neural network method was developed, and external validation predicted final clinical diagnoses of Alzheimer's disease, dementia with Lewy bodies, mild cognitive impairment due to Alzheimer's disease, or cognitively normal with FDG-PET. The translation of artificial intelligence to clinical practice is plagued with technical, disease-related, and institutional challenges. The implementation of artificial intelligence methods in clinical practice has the potential to transform the diagnostic and treatment landscape and improve patient health and outcomes.

Clinical Utility and Safety of an Ultrasonic Head Stimulator in Dementia With Lewy Bodies

BACKGROUND

The potential of Ultra-Ma, an ultrasonic head stimulator, for the supplementary treatment of dementia with Lewy bodies (DLB) was evaluated in patients with various symptoms under poor control by drug therapy.

METHODS

Patients with DLB treated with choline esterase inhibitor or L-DOPA, either alone or in combination, and who met inclusion criteria were enrolled. Four weeks of placebo stimulation was followed by 8 weeks of active ultrasonic stimulation and a 4-week follow-up. Primary endpoints were the effects of ultrasonic head stimulation on both cognitive dysfunction and behavioral and psychological symptoms of dementia (BPSD). Cognitive dysfunction was evaluated using the Japanese versions of the Mini-Mental State Examination and Montreal Cognitive Assessment, and BPSD was assessed using the Neuropsychiatric Inventory Brief Questionnaire Form. For cognitive fluctuations, the Cognitive Fluctuation Inventory served as an index. Improvements in parkinsonism, activities of daily living, and caregiver burden were examined as secondary endpoints.

RESULTS

Twelve patients were enrolled. The primary endpoint was significantly improved during the active stimulation period, as were secondary endpoint ratings for parkinsonism and caregiver burden. No notable adverse events occurred.

CONCLUSIONS

The findings suggest that ultrasonic head stimulation has supplementary potential when combined with drug treatment in DLB.

Phenoconversion in Women and Men With Isolated REM Sleep Behavior Disorder: A Retrospective Cohort Study

BACKGROUND AND OBJECTIVES

Isolated REM sleep behavior disorder (iRBD) is strongly associated with synucleinopathies. Previous iRBD cohort studies have primarily focused on older (>50 years), male-predominant cohorts. Risk of phenoconversion in women and younger adults remains unclear. The study aimed to determine clinical features associated with conversion to a defined neurodegenerative disorder in women and men with iRBD.

METHODS

One hundred eighty-six women and 186 men with iRBD were matched by polysomnography month. Baseline clinical variables and subsequent neurodegenerative outcomes were abstracted by chart review. Kaplan-Meier curves assessed conversion rates. Cox proportional hazards modeling evaluated factors associated with phenoconversion risk.

RESULTS

Age at iRBD diagnosis was younger in women compared with men (54.9 vs 62.5 years, p < 0.01). Forty-eight patients (12.9%), including 18 women (9.7%) and 30 men (16.1%), phenoconverted during a median follow-up of 6.0 years. Conversion rates were lower in antidepressant users and patients with chronic pain or psychiatric comorbidity while rates were higher in those with vascular comorbidity. Only age at diagnosis (HR 1.09, 95% CI 1.06-1.13) was associated with phenoconversion after adjusting for RBD symptom duration; sex; antidepressant use; and psychiatric, chronic pain, and vascular comorbidities.

DISCUSSION

Age at diagnosis was independently associated with phenoconversion risk in women and men with iRBD.

Computerized decision support to optimally funnel patients through the diagnostic pathway for dementia

BACKGROUND

The increasing prevalence of dementia and the introduction of disease-modifying therapies (DMTs) highlight the need for efficient diagnostic pathways in memory clinics. We present a data-driven approach to efficiently guide stepwise diagnostic testing for three clinical scenarios: 1) syndrome diagnosis, 2) etiological diagnosis, and 3) eligibility for DMT.

METHODS

We used data from two memory clinic cohorts (ADC, PredictND), including 504 patients with dementia (302 Alzheimer's disease, 107 frontotemporal dementia, 35 vascular dementia, 60 dementia with Lewy bodies), 191 patients with mild cognitive impairment, and 188 cognitively normal controls (CN). Tests included digital cognitive screening (cCOG), neuropsychological and functional assessment (NP), MRI with automated quantification, and CSF biomarkers. Sequential testing followed a predetermined order, guided by diagnostic certainty. Diagnostic certainty was determined using a clinical decision support system (CDSS) that generates a disease state index (DSI, 0-1), indicating the probability of the syndrome diagnosis or underlying etiology. Diagnosis was confirmed if the DSI exceeded a predefined threshold based on sensitivity/specificity cutoffs relevant to each clinical scenario. Diagnostic accuracy and the need for additional testing were assessed at each step.

RESULTS

Using cCOG as a prescreener for 1) syndrome diagnosis has the potential to accurately reduce the need for extensive NP (42%), resulting in syndrome diagnosis in all patients, with a diagnostic accuracy of 0.71, which was comparable to using NP alone. For 2) etiological diagnosis, stepwise testing resulted in an etiological diagnosis in 80% of patients with a diagnostic accuracy of 0.77, with MRI needed in 77%, and CSF in 37%. When 3) determining DMT eligibility, stepwise testing (100% cCOG, 83% NP, 75% MRI) selected 60% of the patients for confirmatory CSF testing and eventually identified 90% of the potentially eligible patients with AD dementia.

CONCLUSIONS

Different diagnostic pathways are accurate and efficient depending on the setting. As such, a data-driven tool holds promise for assisting clinicians in selecting tests of added value across different clinical contexts. This becomes especially important with DMT availability, where the need for more efficient diagnostic pathways is crucial to maintain the accessibility and affordability of dementia diagnoses.

Brain-derived and in vitro-seeded alpha-synuclein fibrils exhibit distinct biophysical profiles

The alpha-synuclein (αSyn) seeding amplification assay (SAA) that allows the generation of disease-specific in vitro seeded fibrils (SAA fibrils) is used as a research tool to study the connection between the structure of αSyn fibrils, cellular seeding/spreading, and the clinicopathological manifestations of different synucleinopathies. However, structural differences between human brain-derived and SAA αSyn fibrils have been recently highlighted. Here, we characterize the biophysical properties of the human brain-derived αSyn fibrils from the brains of patients with Parkinson's disease with and without dementia (PD, PDD), dementia with Lewy bodies (DLB), multiple system atrophy (MSA), and compare them to the 'model' SAA fibrils. We report that the brain-derived αSyn fibrils show distinct biochemical profiles, which were not replicated in the corresponding SAA fibrils. Furthermore, the brain-derived αSyn fibrils from all synucleinopathies displayed a mixture of 'straight' and 'twisted' microscopic structures. However, the PD, PDD, and DLB SAA fibrils had a 'straight' structure, whereas MSA SAA fibrils showed a 'twisted' structure. Finally, the brain-derived αSyn fibrils from all four synucleinopathies were phosphorylated (S129). Interestingly, phosphorylated αSyn were carried over to the PDD and DLB SAA fibrils. Our findings demonstrate the limitation of the SAA fibrils modeling the brain-derived αSyn fibrils and pay attention to the necessity of deepening the understanding of the SAA fibrillation methodology.

Therapeutic drug monitoring for dose optimization in Alzheimer's disease and in dementia with Lewy bodies: A randomized single-blinded clinical trial

Background

Previous evidence suggests serum concentrations of donepezil varies in clinical populations and that a dose higher than standard may have additional positive effect on cognition. Therapeutic drug monitoring (TDM) is a tool for dose optimization (DO) whereby treatment is adjusted based on previous quantification of the prescribed drug.

Objective

Investigate whether TDM-based DO of donepezil or memantine improves clinical outcomes and/or reduce the frequency of adverse reactions (ARs) in neurodegenerative conditions commonly treated with these two study drugs.

Methods

Single-blinded 1:1 randomized controlled study in an outpatient memory clinic. Eligible participants either newly diagnosed with Alzheimer's disease dementia (AD), dementia with Lewy bodies (DLB), or Parkinson's disease dementia (PDD) scheduled for treatment with donepezil or memantine. The intervention group received TDM based DO. The control group received DO solely based on clinical assessment. Clinical outcomes were change in Mini-Mental State Examination, Addenbrooke's Cognitive Examination, Neuropsychiatric Inventory, and Disability Assessment in Dementia from baseline to 12 months. Additionally, data on incidence and severity of ARs and proportion of participants with a serum concentration within the therapeutic reference range were collected.

Results

132 participants recruited (125 AD, 7 DLB, none with PDD) of whom 107 completed the study (101 AD and 6 DLB), fewer in the control group than planned. Statistical analysis did not reveal significant differences between groups neither for clinical outcomes nor for frequency of ARs.

Conclusions

TDM based DO did not significantly improve clinical outcomes nor reduce the frequency of ARs albeit important caveats to the results apply.

ClincialTrialsgov identifier

NCT04117178 (first posted October 7, 2019).

Global research trends and hotspots in Parkinson's disease psychosis: a 25-year bibliometric and visual analysis

Background

Parkinson's disease psychosis (PDP) is one of the most severe and disabling non-motor symptoms in the progression of Parkinson's disease (PD), significantly impacting the prognosis of PD patients. In recent years, there has been an increase in literature on PDP. However, bibliometrics has rarely been applied to PDP research. This study provides an overview of the current state of PDP research and predicts future trends in this field.

Methods

The literature search was conducted using the Web of Science Core Collection, with the search terms (Parkinson* AND (psychotic* OR hallucination* OR illusion* OR delusion* OR misperception* OR psychosis OR psychoses)). VOSviewer and CiteSpace software were employed to perform bibliometric analysis and visual representation of the search results.

Results

A total of 603 articles were effectively included. Since 2017, there has been a significant upward trend in publications related to PDP. The United States, the United Kingdom, and Canada were the top three contributing countries in terms of publication volume, with France also having a strong influence in this field. Movement Disorders and King's College London included and published the most articles on PDP. The paper titled "Hallucinations in Parkinson's Disease: Prevalence, Phenomenology, and Risk Factors" received the highest number of citations and average citations. Cluster analysis results identified brain, prevalence, connectivity, and atypical antipsychotics as key hotspots in this field. High-frequency keywords were grouped into three themes: neurobiology, therapeutic strategies, and symptom research. Among them, pimavanserin, risk, and functional connectivity have been the most studied areas in the past 7 years and are likely to remain key topics in future research.

Conclusion

Research on PDP has garnered increasing attention. This study visualizes PDP research over the past 25 years to analyze global hotspots and trends. It offers researchers a valuable perspective for identifying key topics and understanding research trajectories in this expanding field.

Hypometabolic mismatch with atrophy and tau pathology in mixed Alzheimer and Lewy body disease

Polypathology is a major driver of heterogeneity in clinical presentation and extent of neurodegeneration (N) in patients with Alzheimer Disease (AD). Beyond amyloid (A) and tau (T) pathologies, over half of patients with AD have concomitant pathology such as α-synuclein (S) in mixed AD with Lewy Body Disease (LBD). Patients with Mixed Etiology Dementia (MED) such as AD+LBD have faster progression and potentially differential responses to targeted treatments, though the diagnosis of AD+LBD can be challenging given overlapping clinical and imaging features. Development and validation of improved in vivo biomarkers are required to study relationships between N and S and identify imaging patterns reflecting mixed AD+LBD pathologies. We hypothesize that individual proteinopathies, such as T and S, are associated with commensurate levels of N. Thus, we assessed biomarkers of A, T, N and S with positron emission tomography (PET), magnetic resonance imaging (MRI) and cerebrospinal fluid (CSF) seeding amplification assay (SAA) data to determine molecular presentations of mixed A+S+ vs. A+S- cognitively impaired patients from the Alzheimer's Disease Neuroimaging Initiative (ADNI). We found A+S+ patients had parieto-occipital 18F-Fluorodeoxyglucose hypometabolism (a measure of N) disproportionate to the degree of regional atrophy or T burden, highlighting worse hypometabolism associated with S+ SAA. Following up on this hypometabolic mismatch with CSF metabolite and proteome analyses, we found that A+S+ patients exhibited lower CSF levels of dopamine metabolites and synaptic markers like neuronal pentraxin-2 (NPTX2), suggesting that altered neurotransmission and neuron integrity contribute to this dissociation between metabolic PET and MRI. Potential confounders exist when studying relations between N, AD and LBD pathologies, including neuroinflammation and other non-Alzheimer pathologies in MED, though our findings imply posterior hypometabolic mismatch is related more to S than vascular or TDP-43 pathology. A+S+ patients had posterior mismatch with excessive 18F-Fluorodeoxyglucose hypometabolism relative to atrophy or T load, possibly reflecting impaired neuron integrity. Further research must disentangle the impact of multiple proteinopathies and clinicopathologic factors on hypometabolism and atrophy. Cumulatively, patients with mixed AD+LBD etiologies harbor a unique metabolic PET mismatch signature.

Whole-genome sequencing to identify rare variants in East Asian patients with dementia with Lewy bodies

Dementia with Lewy bodies (DLB) is the second most common form of age-related dementia, following Alzheimer's disease (AD). DLB is associated with a worse prognosis than AD and is characterized by a more rapid progression of cognitive impairment and a poorer quality of life. In addition, the pathogenesis of DLB is less understood than that of AD, and only three genes-SNCA (α-synuclein), APOE (apolipoprotein E), and GBA1 (glucosylceramidase beta 1)-have been convincingly demonstrated to be associated with DLB. In this study, we utilized whole-genome sequencing data from 1744 Japanese individuals, comprising 45 DLB patients and 1699 cognitively normal older adults, aiming to identify new genes associated with DLB. Our genome-wide association studies of genes with potentially deleterious mutations identified the CDH23 gene as being associated with DLB, reaching a Bonferroni-corrected significance (P = 7.43 × 10-4). The gene contained three ethnicity-specific heterozygous missense variants (rs181275139, rs563688802, and rs137937502). CDH23 has been linked to deafness syndromes, and DLB patients carrying these mutations displayed symptoms of subjective hearing loss, suggesting a potential association between DLB onset and auditory impairment. Additionally, we explored human leukocyte antigen (HLA) genotypes associated with DLB but found no significant associations. This result suggests that the pathology of DLB differs from that of Parkinson's disease, which has been reported to have an association with HLA. Although a limitation of this study is the lack of replication of our findings, which require further validation in independent cohorts, our study enhances the understanding of the etiology of DLB in the Japanese population and provides new insights into the underlying mechanisms of its pathogenesis.

[Diagnosis and management of delirium in older adults]

Delirium, also known as acute confusional state, is an acute brain disorder characterized by cognitive disturbances, particularly attentional deficits, potential behavioral changes, and altered vigilance, with a sudden onset and fluctuating course. It is a common condition among hospitalized older patients and has serious consequences for the patient, their family, and the healthcare system. It is considered an "acute brain failure" that often occurs in the context of underlying cognitive and cerebral vulnerability, similar to how acute kidney injury complicates chronic kidney disease or how acute heart failure exacerbates chronic heart failure - usually in the presence of a precipitating medical factor, often infectious, metabolic, perioperative, or neurological. This narrative review aims to describe the symptoms that allow the diagnosis of delirium in older adults, the available diagnostic or screening tools, as well as the complex and bidirectional relationships between delirium and dementia. The management of delirium, including non-pharmacological measures, will be discussed, along with symptomatic pharmacological treatments, which should be reserved for severe cases despite their low level of evidence.

α-Synuclein seeding amplification assays for diagnosing synucleinopathies: an innovative tool in clinical implementation

The spectrum of synucleinopathies, including Parkinson's disease (PD), multiple system atrophy (MSA), and dementia with Lewy bodies (DLB), is characterized by α-synuclein (αSyn) pathology, which serves as the definitive diagnostic marker. However, current diagnostic methods primarily rely on motor symptoms that manifest years after the initial neuropathological changes, thereby delaying potential treatment. The symptomatic overlap between PD and MSA further complicates the diagnosis, highlighting the need for precise and differential diagnostic methods for these overlapping neurodegenerative diseases. αSyn misfolding and aggregation occur before clinical symptoms appear, suggesting that detection of pathological αSyn could enable early molecular diagnosis of synucleinopathies. Recent advances in seed amplification assay (SAA) offer a tool for detecting neurodegenerative diseases by identifying αSyn misfolding in fluid and tissue samples, even at preclinical stages. Extensive research has validated the effectiveness and reproducibility of SAAs for diagnosing synucleinopathies, with ongoing efforts focusing on optimizing conditions for detecting pathological αSyn in more accessible samples and identifying specific αSyn species to differentiate between various synucleinopathies. This review offers a thorough overview of SAA technology, exploring its applications for diagnosing synucleinopathies, addressing the current challenges, and outlining future directions for its clinical use.

Delirium-onset prodromal Lewy body disease: A series of 5 cases

Background

Delirium-onset prodromal Lewy body disease (LBD) has been proposed as one of the primary phenotypes of prodromal stages of LBD. The detailed clinical features and biomarker profiles of delirium-onset prodromal LBD have not been well characterized.

Methods

Five consecutive cases of delirium-onset prodromal LBD were documented. The diagnosis of prodromal LBD was made based on neuroimaging biomarkers, including dopamine transporter single-photon emission computed tomography (SPECT), cardiac 123I-metaiodobenzylguanidine scintigraphy, and/or brain perfusion SPECT, as well as clinical findings in the post-delirium follow-up periods.

Results

In all cases, one or more of the core or supportive clinical features of dementia with Lewy bodies, including rapid eye movement sleep behavior disorder, minor hallucinations, hyposmia, or autonomic dysfunction, were present prior to the onset of delirium. The precipitating factors for delirium were diverse, including surgery, radiation therapy, chemotherapy, and infection. The duration of delirium was prolonged for several months in two cases, whereas it was resolved within a few weeks in the other cases. In most cases, persistent mild cognitive or behavioral symptoms were observed, which were improved with donepezil.

Conclusions

Our observations suggest that delirium-onset prodromal LBD may represent the later stages of the prodromal LBD rather than its initial stages. It is possible that delirium in the prodromal stages of LBD may represent subthreshold cognitive fluctuations that are transformed into clinically detectable states by a variety of precipitating factors.

Comparison of MIBG uptake in the major salivary glands between Lewy body disease and progressive supranuclear palsy

Introduction

Cardiac sympathetic denervation is specific to Lewy body disease (LBD). In Parkinson's disease (PD), sympathetic denervation in the major salivary glands (parotid glands [PG] and submandibular glands [SMG]) has been demonstrated by 123I-metaiodobenzylguanidine (MIBG) scintigraphy. We compared sympathetic denervation in the MSG between PD, dementia with Lewy bodies (DLB), and progressive supranuclear palsy (PSP).

Methods

We recruited 81 patients with PD, 12 with DLB, 13 with PSP and 25 with control subjects. We evaluated MIBG uptake in the major salivary glands and heart using a quantitative semi-automatic method. We compared MIBG uptake between PD, DLB, and PSP patients and controls, and we evaluated disease sensitivity and specificity. We compared olfactory function with MIBG uptake between PD and PSP patients.

Results

MIBG uptake in the PG and SMG in the delayed phase was significantly lower in PD and DLB patients than in PSP patients and controls. Conversely, MIBG uptake in the major salivary glands and heart was comparable between PD and DLB. Between LBD and non-LBD, MIBG uptake showed 56-100 % specificity in the PG, while it had 55.6-87.5 % sensitivity in the SMG. Between PD and PSP, MIBG uptake in the PG and SMG had higher disease specificity than olfactory function, while the sensitivity of SMG MIBG uptake was comparable to olfactory function.

Conclusion

PD and DLB patients showed lower MIBG uptake in the major salivary glands than PSP patients, especially in the delayed phase. MIBG uptake in the major salivary glands may differentiate PD from hyposmic PSP.

Elevated plasma total homocysteine levels are associated with behavioral and psychological symptoms in dementia with Lewy bodies

Objective

To investigate the association between plasma total homocysteine (tHcy) levels and behavioral and psychological symptoms of dementia (BPSD) in dementia with Lewy bodies (DLB) patients.

Methods

A total of 82 DLB patients and 134 age-matched healthy controls were included in this study. DLB patients were assessed using the Mini-Mental Status Examination (MMSE), the Clinical Dementia Rating Scale (CDR), and the Neuropsychiatric Inventory (NPI). Plasma tHcy, serum vitamin B12, and folate levels were measured in all study participants. We used Spearman's rank correlation test to analyze the association between tHcy concentrations and NPI scores, MMSE, CDR, and the duration of dementia in DLB patients.

Results

Clinically significant BPSD was present in 92.7% of DLB patients. The most frequent BPSD were hallucinations (30.4%), apathy (30.4%), and delusions (26.8%). Elevated plasma tHcy levels were significantly associated with total NPI scores in DLB patients, particularly in 10 NPI sub-domains, except for agitation/aggression and disinhibition. No statistically significant association was found between plasma tHcy levels and MMSE, CDR, or dementia duration.

Limitations

Longitudinal studies with larger sample sizes are required to further explore the relationship between tHcy levels and BPSD in DLB patients as the disease progresses.

Conclusion

Our study highlighted the high incidence of BPSD and was the first to show that BPSD is associated with elevated plasma tHcy levels in DLB patients in China. These results support the hypothesis that controlling homocysteine levels could offer a new direction for managing BPSD.

Psychiatric symptoms and TDP-43 pathology in amyotrophic lateral sclerosis

BACKGROUND

ALS is not a pure motor neuron disease but co-occurs with cognitive impairment and psychiatric symptoms. The neuropathological origin of the psychiatric symptoms is unclear. This study examined the association between the psychiatric symptoms and neuropathology of ALS.

METHODS

We investigated the clinicopathological characteristics of 15 autopsy cases of ALS, including neuronal loss, gliosis, and the burden of TDP-43 pathology. We divided TDP-43-positive structures by morphology into four categories (neuronal cytoplasmic inclusion, dystrophic neurite, dot, and glial cytoplasmic inclusion) and gave each a semiquantitative score in nine brain regions. Braak neurofibrillary tangle stage, Thal amyloid phase, Lewy-related pathology, and argyrophilic grains were also assessed.

RESULTS

Of the 15 ALS patients, seven had presented with psychiatric symptoms and eight had not. Significantly higher TDP-43 pathology scores were found in the group with psychiatric symptoms in the temporal tip, transentorhinal cortex, entorhinal cortex, subiculum, and the hippocampal CA1 region and dentate gyrus. Cognitive impairment was not significantly associated with the degree of TDP-43 pathology. There were no significant differences in the degree of neuronal loss/gliosis or in other concurrent pathologies between patients with and without psychiatric symptoms. Morphological evaluation showed that neuronal cytoplasmic inclusions, dystrophic neurites, and dots tended to be more common in the group with psychiatric symptoms.

CONCLUSION

Psychiatric symptoms in ALS may be related to TDP-43 pathology in the perforant pathway. (224 words).

An SBM and TBSS Analysis in Early-stage Patients With Alzheimer's Disease, Lewy Body Dementias, and Corticobasal Syndrome

OBJECTIVE

To compare gray matter (GM) and white matter (WM) changes in patients with Alzheimer's disease (AD), Lewy body dementias (LBD), corticobasal syndrome (CBS), and healthy controls (HC).

METHODS

Surface-based morphometry (SBM) was assessed on 3D T1-weighted images using FreeSurfer image analysis and WM microstructure was studied using Tract-Based Spatial Statistics (TBSS) in 12 AD, 15 LBD, 10 CBS patients, and 10 HC.

RESULTS

Patients with AD, compared with HC, exhibited reduced cortical surface area and volume in the superior frontal, middle frontal, and medial orbitofrontal cortex. In TBSS, AD patients, compared with HC and LBD, displayed decreased fractional anisotropy, axial diffusivity, and increased radial diffusivity in all major WM tracts. Other comparisons between the groups yielded no differences, either in the SBM or the TBSS analysis.

CONCLUSIONS

The results indicate significant early structural changes in the GM of the frontal lobe, along with WM alterations early in AD patients.

Primary Progressive Aphasia Lacking Core Features of Nonfluent and Semantic Variants: Clinical, Neuroimaging, and Neuropathologic Features

BACKGROUND AND OBJECTIVES

Evidence has accumulated that the 2011 consensus criteria for primary progressive aphasia (PPA) do not fully capture features of logopenic variant PPA (lvPPA/LPA). We aimed to examine clinical, neuroimaging, and neuropathologic features of PPA lacking features of nonfluent/semantic variants and to provide practical additions to the 2011 consensus criteria.

METHODS

This was a retrospective examination of data from 2 observational cohort studies where patients with PPA were prospectively recruited at Mayo Clinic. Based on performance on 2 cardinal features (repetition and comprehension), patients were classified as: pure-LPA (poor repetition, acceptable comprehension), Wernicke-like (poor in both), anomic-like (acceptable in both), and transcortical sensory aphasia-like (TCSA-like) (acceptable repetition, poor comprehension).

RESULTS

The entire cohort consisted of 102 patients with PPA lacking features of nonfluent/semantic variants (median age at onset 63.5 years, 56% female). Thirty-one patients were followed up at 1 year. Twenty-three patients were included in a neuropathologic cohort. The proportion of repetition-preserved PPA (anomic-like and TCSA-like) was more than double that of repetition-impaired PPA (pure-LPA and Wernicke-like) (73% vs 27%). Regarding clinical course, the anomic-like subgroup was a prodromal state of the pure-LPA or TCSA-like subgroup, whereas the pure-LPA and TCSA-like subgroups were a prodromal state of the Wernicke-like subgroup. There was left temporoparietal atrophy on MRI and/or hypometabolism on 18F-fluorodeoxyglucose-PET in all groups. Furthermore, repetition-impaired PPA showed severe hypometabolism in the left superior temporal lobe associated with repetition ability. Regarding pathologic diagnoses, 70% had Alzheimer disease (AD). The pure-LPA, Wernicke-like, and TCSA-like subgroups all showed AD pathology. Only 53% of the anomic-like subgroup had AD. The remaining 47% showed Pick disease (7%), frontotemporal lobar degeneration with TDP-43-immunoreactive pathology (20%), and Lewy body disease (20%).

DISCUSSION

This observed clinical heterogeneity reflects different time points/severities of the same disease process and hence can be reconceptualized as an AD-related aphasia spectrum, incorporating lvPPA and the 4 subgroups (pure-LPA, Wernicke-like, anomic-like, and TCSA-like). Specifying moderate/severe repetition deficits as a core feature of lvPPA in the 2011 consensus criteria can enhance its pathologic correlations. Recognizing progressive anomic aphasia (anomic-like) as an additional PPA variant could lessen pathologic heterogeneity of lvPPA.

Attention Network Dysfunctions in Lewy Body Dementia and Alzheimer's Disease

Background: Attention deficits are notable in Lewy body dementia (LBD) and in Alzheimer's disease (AD). In this study, we combined functional magnetic resonance imaging (fMRI) and electroencephalograph (EEG) to detect neural correlates of attention dysfunctions in LBD and AD. Methods: We recruited 33 patients with LBD, 15 patients with AD and 19 elderly healthy controls. The participants performed the modified Attention Network Task (ANT) to investigate the attention dysfunctions. Results: We found that LBD had alerting attention deficits and AD showed apparent orienting attention dysfunctions, while LBD and AD maintained relatively normal executive/conflict attention. Based on source-level EEG analyses, LBD had frontal-central deficits for alerting attention while AD showed inferior frontal and precentral impairments for orienting attention. In addition, the insular and inferior frontal areas were hyper-activated in LBD and AD for executive/conflict attention. Apart from these areas, LBD showed activity in the complementary temporal-central-occipital network for the modified ANT task. Furthermore, the oscillational sources for the ANT effects indicated that the alpha and theta bands were partly impaired in dementia patients. Conclusions: In summary, using source-localised EEG, we found that attention dysfunctions in LBD and AD engaged different neural networks.

Alpha tACS Improves Cognition and Modulates Neurotransmission in Dementia with Lewy Bodies

BACKGROUND

Dementia with Lewy bodies (DLB) is characterized by a marked shift of electroencephalographic (EEG) power and dominant rhythm, from the α toward the θ frequency range. Transcranial alternate current stimulation (tACS) is a non-invasive brain stimulation technique that allows entrainment of cerebral oscillations at desired frequencies.

OBJECTIVES

Our goal is to evaluate the effects of occipital α-tACS on cognitive functions and neurophysiological measures in patients with DLB.

METHODS

We conducted a double-blind, randomized, sham-controlled, cross-over clinical trial in 14 participants with DLB. Participants were randomized to receive either α-tACS (60 minutes of 3 mA peak-to-peak stimulation at 12 Hz) or sham stimulation applied over the occipital cortex. Clinical evaluations were performed to assess visuospatial and executive functions, as well as verbal episodic memory. Neurophysiological assessments and EEG recordings were conducted at baseline and following both α-tACS and sham stimulations.

RESULTS

Occipital α-tACS was safe and well-tolerated. We observed a significant enhancement in visuospatial abilities and executive functions, but no improvement in verbal episodic memory. We observed an increase in short latency afferent inhibition, a neurophysiological marker indirectly and partially dependent on cholinergic transmission, coinciding with an increase in α power and a decrease in Δ power following α-tACS stimulation, effects not seen with sham stimulation.

CONCLUSIONS

This study demonstrates that occipital α-tACS is safe and enhances visuospatial and executive functions in patients with DLB. Improvements in indirect markers of cholinergic transmission and EEG changes indicate significant neurophysiological engagement. These findings justify further exploration of α-tACS as a therapeutic option for DLB patients. © 2024 The Author(s). Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Validity and reliability of the Turkish version of the ALBA screening instrument for Lewy body dementia in older adults

ALBA screening instrument (ASI) has been demonstrated to be an effective, cheap, and noninvasive clinical instrument to screen for Lewy body dementia (LBD). We aimed to determine the validity and reliability of the Turkish version of ASI (ASI-T) in patients with LBD and to investigate the discriminative power of the test in patients with Alzheimer's Disease (AD), LBD, and cognitively healthy older adults (controls). 172 older adults over 60 years of age (43 with LBD, 41 AD, and 88 controls) were included. The sensitivity and specificity of the instrument were determined. A significant difference was found in ASI-T total score between people with LBD versus the controls (t=-9.259; p < 0.001), and versus patients with AD (t = 3.490; p = 0.001). Internal consistency of the ASI-T was good(Cronbach's alpha = 0.81). The cutoff score of 7 showed sensitivity (86%) and specificity (81%) (AUC= 0.888,CI0.95, p < 0.001) compared to controls. Also, compared to AD, it showed sensitivity (86%) and specificity(70%) (AUC = 0.590,CI .95, p < 0.001). Moreover, ASI-T demonstrated a significant concurrent validity with MMSE (r = -0.62; p < 0.001) and MoCA (r = -0.54; p = 0.003). In factor analysis, the five subscales accounted for 60% of the total variance. Our findings suggested that the ASI-T is a reliable, valid, and effective instrument for screening LBD. With acceptable psychometric properties, it has the power to distinguish patients with LBD from controls or those with AD.

The association between cigarette smoking and dementia with Lewy bodies

INTRODUCTION

Cigarette smoking is associated with a reduced risk of Parkinson's disease (PD). As dementia with Lewy bodies (DLB) and PD share core neuropathologic features, we set out to examine the relationship between smoking and DLB.

METHODS

Diagnosis at baseline visit and smoking history of participants ≥50 years old in the National Alzheimer's Coordinating Center (NACC) cohort were evaluated in this cross-sectional study. Odds of diagnosis of cognitive impairment due to DLB, PD, vascular dementia (VD), or Alzheimer's disease (AD) compared to normal cognition based on smoking status and duration were determined using logistic regression.

RESULTS

37,478 participants were included (mean age 72 years (SD 9), 57 % female). The odds of DLB were reduced in all smoking status groups compared to never smokers (OR (95 % CI)): ever smokers 0.850 (0.745-0.971), former smokers 0.871 (0.761-0.997), current smokers 0.640 (0.419-0.947)) and in all smoking duration groups. As expected, the odds of PD were reduced in all smoking groups and fell with longer smoking duration. The odds of VD were increased in the current smoking group and rose with greater smoking duration. The odds of AD were unchanged in current smokers, decreased in ever and former smokers, and increased with longer cumulative smoking duration.

CONCLUSIONS

Cigarette smoking is associated with lower odds of diagnosis of DLB at baseline visit in the NACC cohort. In the context of the well-established reduced risk of PD among smokers, this preliminary evidence of a potential protective effect of smoking on DLB warrants further study.

Neuropsychiatric symptoms and white matter hyperintensities in older adults without dementia

OBJECTIVE

We aimed to examine associations between neuropsychiatric symptoms (NPS) and white matter hyperintensities (WMH) status in older adults without dementia under the hypothesis that WMH increased the odds of having NPS.

DESIGN

Longitudinal analysis of data acquired from the National Alzheimer's Coordinating Center Uniform Data Set.

SETTINGS

Data were derived from 46 National Institute on Aging - funded Alzheimer's Disease Research Centers.

PARTICIPANTS

NACC participants aged ≥50 years with available data on WMH severity with a diagnosis of mild cognitive impairment (MCI) or who were cognitively unimpaired (CU) were studied. Among 4617 CU participants, 376 had moderate and 54 extensive WMH. Among 3170 participants with MCI, 471 had moderate and 88 had extensive WMH.

MEASUREMENTS

Using Cardiovascular Health Study (CHS) scores, WMH were coded as no to mild (CHS score: 0-4), moderate (score: 5-6) or extensive (score: 7-8). NPS were quantified on the Neuropsychiatric Inventory Questionnaire. Binary logistic regression models estimated the odds of reporting each of 12 NPS by WMH status separately for individuals with MCI or who were CU.

RESULTS

Compared to CU individuals with no to mild WMH, the odds of having elation [9.87, (2.63-37.10)], disinhibition [4.42, (1.28-15.32)], agitation [3.51, (1.29-9.54)] or anxiety [2.74, (1.28-5.88)] were higher for the extensive WMH group, whereas the odds of having disinhibition were higher for the moderate WMH group [1.94, (1.05-3.61)]. In the MCI group, he odds of NPS did not vary by WMH status.

CONCLUSIONS

Extensive WMH were associated with higher odds of NPS in CU older adults but not in those with MCI.

Validation and extension of the quick dementia rating system (QDRS)

Informant report dementia severity staging measures, such as the Quick Dementia Rating System (QDRS) offer clinicians useful diagnostic and staging information. These measures also potentially avoid many of the pitfalls inherent in mental status examinations (e.g., cultural bias, educational bias, floor and ceiling effects). We derive cut points for the QDRS and comprehensively examine their classification accuracy in a large, diagnostically heterogeneous, rural, memory disorder clinic sample. Our findings suggest the QDRS may be helpful when used in the context of a comprehensive diagnostic and staging evaluation. When used in isolation, the QDRS is insufficiently accurate for diagnosis and staging of dementia.

Plasma p-tau181 and amyloid markers in Alzheimer's disease: A comparison between Lumipulse and SIMOA

Aim of the project was to evaluate the technical and clinical validity of plasma Lumipulse p-tau, Aβ42 and Aβ40 species and their correlation with CSF core Alzheimer's Disease (AD) markers; a method comparison with SIMOA was also performed. One-hundred-thirthy-three participants, namely 55 A+T+N+ AD, 28 Neurodegenerative disorders (NDD) and 50 controls were enrolled for the study. Lumipulse technical validity showed high stability for p-tau181, Aβ42, and Aβ40, with higher stability of p-tau to repeated freezing thaw cycles. p-tau181 levels detected by both techniques were higher in AD compared to both NDD/controls and exhibited a similar correlation with CSF p-tau levels, whereas Aβ42 levels were slightly lower in AD with both methods. In the comparison between SIMOA and Lumipulse plasma markers, both techniques exhibited similar diagnostic accuracy for AD for p-tau181 (0.87; 95 %CI 0.81-0.94, vs 0.85; 95 %CI 0.78-0.93), whereas the best performance was reached by p-tau181/ Aβ42 Lumipulse ratio (ROC AUC 0.915, 95 %CI 0.86-0.97). The study thus confirmed the construct validity of both Lumipulse and SIMOA techniques for the identification of CSF AD pattern in clinical settings.

Insular monoaminergic deficits in prodromal α-synucleinopathies

METHODS

This study assessed data from two cohorts of patients with alpha-synucleinopathies (University of Brescia and University of Rome Tor-Vergata cohorts). Consecutive participants with video-polysomnography-confirmed iRBD, Parkinson's disease (PD), dementia with Lewy bodies (DLB) and controls underwent neurological, clinical and 123I-FP-CIT SPECT imaging assessments. Individuals with iRBD were longitudinally monitored to collect clinical phenoconversion to PD or DLB. The main outcome was to identify whole brain 123 I-FP-CIT SPECT measures reflecting monoaminergic deficits in each clinical group as compared to controls.

RESULTS

The cohort (n = 184) included 45 patients with iRBD, 47 PD, 42 DLB and 50 age-matched controls. Individuals with iRBD were categorized as RBD-DAT- (n = 32) and RBD-DAT+ (n = 13), according to nigrostriatal assessment used in clinical practice. Compared to controls, RBD-DAT- showed an early involvement of the left insula, which increased in RBD-DAT+, and was present in patients with Parkinson's disease and dementia with Lewy bodies. Longitudinal cox regression analyses revealed a higher risk of phenoconversion in individuals with iRBD and insular monoaminergic deficits [HR = 3.387; CI 95%: 1.18-10.27].

INTERPRETATION

In this study, altered insular monoaminergic binding in iRBD was associated with phenoconversion to DLB or PD. These findings may provide a helpful stratification approach for future pharmacological or non-pharmacological interventions.

Network Analysis of Brain and Bone Tissue Transcripts Reveals Shared Molecular Mechanisms Underlying Alzheimer's Disease and Related Dementias and Osteoporosis

BACKGROUND

Alzheimer's disease and related dementias (ADRD) and osteoporosis (OP) are 2 prevalent diseases of aging with demonstrated epidemiological association, but the underlying molecular mechanisms contributing to this association are unknown.

METHODS

We used network analysis of bone and brain transcriptomes to discover common molecular mechanisms underlying these 2 diseases. Our study included RNA-sequencing data from the dorsolateral prefrontal cortex tissue of autopsied brains in 629 participants from ROSMAP (Religious Orders Study and the Rush Memory and Aging Project), with a subgroup of 298 meeting criteria for inclusion in 5 ADRD categories, and RNA array data from transiliac bone biopsies in 84 participants from the Oslo study of postmenopausal women. After developing each network within each tissue, we analyzed associations between modules (groups of coexpressed genes) with multiple bone and neurological traits, examined overlap in modules between networks, and performed pathway enrichment analysis to discover conserved mechanisms.

RESULTS

We discovered 3 modules in ROSMAP that showed significant associations with ADRD and bone-related traits and 4 modules in Oslo that showed significant associations with multiple bone outcomes. We found significant module overlap between the 2 networks in modules linked to signaling, tissue homeostasis, and development, and Wingless-related integration site (Wnt) signaling was found to be highly enriched in OP and ADRD modules of interest.

CONCLUSIONS

These results provide translational opportunities in the development of treatments and biomarkers for ADRD and OP.

The Bender Gestalt Test is useful for clinically diagnosing dementia with Lewy bodies: Analysis of its sensitivity, specificity, and clinical characteristics of the figure copy

A previous study that evaluated the ability of the Bender Gestalt Test (BGT) to discriminate between dementia with Lewy bodies (DLB) and Alzheimer's disease (AD) suggested that a total score of 98 is the optimal cutoff value for discriminating between these two diseases and that DLB tends to exhibit unique errors; i.e., "element deformation" and "gestalt destruction." The objectives of the present study were: (1) to examine the sensitivity and specificity of a total BGT score of 98 as a cutoff value in greater numbers of DLB patients than in the previous study, (2) to set a new cutoff value if a cutoff value of 98 is not optimal, and (3) to clarify the frequency of element deformation and gestalt destruction in DLB patients. The participants were 133 DLB patients, 65 AD patients, and 30 cognitively normal elderly people. All of the participants underwent the Mini-Mental State Examination, BGT, and brain magnetic resonance imaging. As a result, the total BGT score cutoff value of 98 showed low sensitivity (0.58), and a cutoff value of 84 was indicated to be the optimal cutoff value for discriminating between DLB and AD. In addition, 32 out of 133 DLB patients and one out of 65 AD patients exhibited element deformation or gestalt destruction. This study suggested that the BGT is a useful neuropsychological test for differentiating DLB from AD. In addition, the need to evaluate the spatial and perceptual difficulties of DLB patients with various types of visual stimulation is also discussed.

ComBat models for harmonization of resting-state EEG features in multisite studies

OBJECTIVE

Pooling multisite resting-state electroencephalography (rsEEG) datasets may introduce bias due to batch effects (i.e., cross-site differences in the rsEEG related to scanner/sample characteristics). The Combining Batches (ComBat) models, introduced for microarray expression and adapted for neuroimaging, can control for batch effects while preserving the variability of biological covariates. We aim to evaluate four ComBat harmonization methods in a pooled sample from five independent rsEEG datasets of young and old adults.

METHODS

RsEEG signals (n = 374) were automatically preprocessed. Oscillatory and aperiodic rsEEG features were extracted in sensor space. Features were harmonized using neuroCombat (standard ComBat used in neuroimaging), neuroHarmonize (variant with nonlinear adjustment of covariates), OPNested-GMM (variant based on Gaussian Mixture Models to fit bimodal feature distributions), and HarmonizR (variant based on resampling to handle missing feature values). Relationships between rsEEG features and age were explored before and after harmonizing batch effects.

RESULTS

Batch effects were identified in rsEEG features. All ComBat methods reduced batch effects and features' dispersion; HarmonizR and OPNested-GMM ComBat achieved the greatest performance. Harmonized Beta power, individual Alpha peak frequency, Aperiodic exponent, and offset in posterior electrodes showed significant relations with age. All ComBat models maintained the direction of observed relationships while increasing the effect size.

CONCLUSIONS

ComBat models, particularly HarmonizeR and OPNested-GMM ComBat, effectively control for batch effects in rsEEG spectral features.

SIGNIFICANCE

This workflow can be used in multisite studies to harmonize batch effects in sensor-space rsEEG spectral features while preserving biological associations.

A Novel Mutation of FOXC1 (P136L) in an Axenfeld-Rieger Syndrome Patient With a Systematized Delusion of Jealousy: A Case Report and Literature Review

BACKGROUND

The main features of Axenfeld-Rieger Syndrome (ARS) are ocular, auditory, neurological, and morphological brain abnormalities. Mutations in forkhead box protein C1 (FOXC1) are among the responsible genes causing ARS, but neuropsychiatric features have rarely been reported. The case of an ARS patient (a 77-year-old man) with delusions of jealousy and impairment of working memory, in addition to the main clinical features, glaucoma and leukoencephalopathy, is presented.

METHODS

The mutation in the patient's genome was found with whole exome sequencing and in silico analysis using PolyPhen-2 and SIFT. Furthermore, AlphaFold2 and PyMOL were used to predict the protein structure based on the mutation.

RESULTS

A novel mutation at the forkhead domain of FOXC1 gene (c.408C>A, p.Phe136Leu) was found and confirmed in the patient's family, and it was predicted to cause protein damage; the SIFT score was 0, meaning deleterious, and the PolyPhen2 result also indicated damaging (score: 0.997). The predicted protein structure based on the novel mutation was different from that of the native structure. In the literature review, 6 of 95 (6.3%) cases showed neuropsychiatric features. Of them, 5 of 6 (83.3%) mutations were located in the forkhead domain.

CONCLUSION

A novel mutation was found in the FOXC1 gene (c.408C>A, p.Phe136Leu), which possibly induces delusions of jealousy and impairment of working memory, as well as features of ARS, by changing the protein structure. Mutations in that domain of the FOXC1 gene may be important not only for ocular abnormalities but also for brain function.

Brain perfusion SPECT in dementia: what radiologists should know

The findings of brain perfusion single-photon emission computed tomography (SPECT), which detects abnormalities often before changes manifest in morphological imaging, mainly reflect neurodegeneration and contribute to dementia evaluation. A major shift is about to occur in dementia practice to the approach of diagnosing based on biomarkers and treating with disease-modifying drugs. Accordingly, brain perfusion SPECT will be required to serve as a biomarker of neurodegeneration. Hypoperfusion in Alzheimer's disease (AD) is typically seen in the posterior cingulate cortex and precuneus early in the disease, followed by the temporoparietal cortices. On the other hand, atypical presentations of AD such as the posterior variant, logopenic variant, frontal variant, and corticobasal syndrome exhibit hypoperfusion in areas related to symptoms. Additionally, hypoperfusion especially in the precuneus and parietal association cortex can serve as a predictor of progression from mild cognitive impairment to AD. In dementia with Lewy bodies (DLB), the differentiating feature is the presence of hypoperfusion in the occipital lobes in addition to that observed in AD. Hypoperfusion of the occipital lobe is not a remarkable finding, as it is assumed to reflect functional loss due to impairment of the cholinergic and dopaminergic systems rather than degeneration per se. Moreover, the cingulate island sign reflects the degree of AD pathology comorbid in DLB. Frontotemporal dementia is characterized by regional hypoperfusion according to the three clinical types, and the background pathology is diverse. Idiopathic normal pressure hydrocephalus shows apparent hypoperfusion around the Sylvian fissure and corpus callosum and apparent hyperperfusion in high-convexity areas. The cortex or striatum with diffusion restriction on magnetic resonance imaging in prion diseases reflects spongiform degeneration and brain perfusion SPECT reveals hypoperfusion in the same areas. Brain perfusion SPECT findings in dementia should be carefully interpreted considering background pathology.

Associations of cerebrospinal fluid monoamine metabolites with striatal dopamine transporter binding and 123I-meta-iodobenzylguanidine cardiac scintigraphy in Parkinson's disease: Multivariate analyses

Cerebrospinal fluid (CSF) homovanillic acid (HVA) and 5-hydroxyindole acetic acid (5-HIAA), dopamine and serotonin metabolites, are decreased in Parkinson's disease (PD). Although some reported associations between HVA and striatal dopamine transporter (DAT) or 5-HIAA and cardiac 123I-meta-iodobenzylguanidine (MIBG) findings, respectively, whether these are direct associations remained unknown. We retrospectively reviewed 57 drug-naïve patients with PD who underwent CSF analyses and DAT and cardiac MIBG imaging. Z-score of striatal DAT specific binding ratio (Z-SBR) was measured, and the positivity of MIBG abnormalities were judged by an expert. The mean age was 75.5 ± 8.7 years. Thirty-three were MIBG-positive and 24 were MIBG-negative. 5-HIAA levels were significantly lower in the MIBG-positive group. Logistic regression analysis showed that MIBG positivity was associated with 5-HIAA level (odds ratio = 0.751, p = 0.006) but not with age, sex, and HVA. DAT Z-SBR correlated with both HVA and 5-HIAA. Multiple regression analysis showed that HVA was the only significant variable associated with Z-SBR (t = 3.510, p < 0.001). We confirmed direct associations between 5-HIAA and cardiac MIBG, and between HVA and striatal DAT binding.

Sex Differences in Neuropsychiatric Symptoms in Alpha-Synucleinopathies: A Systematic Review and Meta-Analysis

BACKGROUND

Alpha-synucleinopathies, such as Parkinson's disease (PD), Parkinson's disease dementia (PDD), and dementia with Lewy bodies (DLB), demonstrate sex differences with regard to prevalence, age of onset, and motor manifestations. Neuropsychiatric symptoms (NPS) are common early and late manifestations of these disorders.

OBJECTIVES

We aimed to describe sex differences in NPS across alpha-synucleinopathies.

METHODS

We searched Web of Science Core collection databases to identify observational studies published between January 1, 2000, and June 1, 2022, reporting the prevalence or severity of NPS among individuals with a diagnosis of PD, PDD, or DLB. Prevalence and severity were pooled for each NPS according to sex using random-effects models.

RESULTS

Two-hundred-and-forty studies, representing 796,026 participants (45% females), were included in the meta-analysis. Female sex was associated with a higher prevalence of anxiety (OR = 1.60 [95% CI: 1.40, 1.82]), depression (OR = 1.56 [1.45, 1.67]), fatigue (OR = 1.21 [1.02, 1.43]), and psychotic symptoms (OR = 1.26 [1.14, 1.40]) and more severe anxiety (g = 1.35 [95% CI: 0.58, 2.13]), depression (g = 1.57 [1.05, 2.08]), and fatigue (g = 0.86 [0.41, 1.32]), while male sex was associated with a higher prevalence of apathy (OR = 0.77 [0.63, 0.93]), impulse control disorders (OR = 0.67 [0.55, 0.82]), REM sleep behavior disorder (OR = 0.54 [0.42, 0.70]), hypersomnolence (OR = 0.67 [0.56, 0.80]), and suicide (OR = 0.30 [0.20, 0.44]).

CONCLUSIONS

NPS have different prevalences and severities in alpha-synucleinopathies according to sex. These findings support consideration of sex in the elaboration of clinical tools.

Anthropometric and Demographic Features Affect the Interpretation of Cerebrospinal Fluid Biomarkers in Patients with Different Dementia Syndromes and Cognitively Healthy Adults

Clinical distinction between dementia with Lewy bodies (DLB) and late-onset Alzheimer's disease (AD) is difficult, while several features might affect the analyses of biomarkers. This study aimed to verify associations of anthropometric and demographic features with cerebrospinal fluid biomarkers, their ratios, and restructured traditional regression formulas in patients with DLB and AD, as well as in cognitively healthy controls. Consecutive outpatients with DLB were paired with outpatients with AD according to sex, dementia stage, and cognitive status, and with controls according to sex and age to investigate associations of sex, age, dementia duration, total sleep time, body mass index, alcohol use, smoking, sanitation, and APOE-ε4 alleles on the measurement of cerebrospinal fluid α-synuclein, biomarker ratios, and restructured traditional regression formulas involving amyloid-β (Aβ42,Aβ40,Aβ38), tau, and phospho-tau Thr181. Overall, 81 participants were included with DLB (n = 27;11 APOE-ε4 +) or AD (n = 27;12 APOE-ε4 +), and controls (n = 27;4 APOE-ε4 +); two thirds were women. Cerebrospinal fluid evidence of amyloidosis and tauopathy was more prevalent among women with AD, while Aβ42/Aβ38 could also discriminate men with DLB from men with AD. Restructured traditional regression formulas had higher diagnostic accuracy for women with AD. Aging, higher body mass index, and APOE-ε4 alleles were associated with amyloidosis in DLB, while only in AD were higher body mass index associated with lower tau pathology load, and more alcohol use associated with higher phospho-tau Thr181/Aβ42. These findings confirm the effects of anthropometric and demographic features on cerebrospinal fluid biomarkers, and also differences in aberrant amyloidosis and tauopathy between DLB and AD.

Dementia: Common Syndromes and Modifiable Risk and Protective Factors

Dementia is an umbrella term for multiple conditions that lead to progressive cognitive decline and impaired activities of daily living. Neuropsychological evaluation is essential for characterizing the distinct cognitive and behavioral profile that can aid in the diagnostic process and treatment planning for dementia. Modifiable risk factors for dementia such as nutrition, physical activity, sleep, cognitive and social engagement, and stress provide important avenues for prevention. Neurologists and other health care providers can help patients reduce their risk for dementia by providing them with education about modifiable factors and connecting them to resources to empower them to engage in brain-healthy behavior.

Biomarker Assessment in Parkinson's Disease Dementia and Dementia with Lewy Bodies by the Immunomagnetic Reduction Assay and Clinical Measures

Background

Plasma biomarker assays provide an opportunity to reassess whether Alzheimer's disease, Parkinson's disease dementia (PDD), and dementia with Lewy bodies (DLB) plasma biomarkers are diagnostically useful.

Objective

We hypothesized that immunomagnetic reduction (IMR) of plasma biomarkers could differentiate between patients with PDD and DLB and healthy patients when combined with established clinical testing measures.

Methods

Plasma samples from 61 participants (12 PDD, 12 DLB, 37 controls) were analyzed using IMR to quantify amyloid-β 42 (Aβ42), total tau (t-tau), phosphorylated tau at threonine 181 (p-tau181), and α-synuclein (α-syn). Receiver operating characteristic curve (ROC) analysis was used to obtain sensitivity, specificity, and area under the ROC curve. Biomarker results were combined with clinical measures from the Unified Parkinson's Disease Rating Scale (UPDRS), Montreal Cognitive Assessment, and Hoehn-Yahr stage to optimize diagnostic test performance.

Results

Participants with PDD had higher α-syn than those with DLB and healthy participants and were distinguishable by their biomarker products Aβ42×p-tau181 and Aβ42×α-syn. Patients with DLB had higher p-tau181 than those with PDD and healthy participants and were distinguishable by their concentrations of α-syn×p-tau181. Plasma α-syn plus UPDRS versus either test alone increased sensitivity, specificity, and AUC when healthy patients were compared with those with PDD and DLB. Combined clinical examination scores and plasma biomarker products demonstrated utility in differentiating PDD from DLB when p-tau181 was combined with UPDRS, α-syn was combined with UPDRS, and α-syn×p-tau181 was combined with UPDRS.

Conclusions

In this pilot study, IMR plasma p-tau181 and α-syn may discriminate between PDD and DLB when used in conjunction with clinical testing.

A Novel Computerized Flexible Attention Test in Detecting Executive Dysfunction of Patients with Early-Onset Cognitive Impairment and Dementia

OBJECTIVE

The number of computer-based cognitive tests has increased in recent years, but there is a need for tests focusing on the assessment of executive function (EF), as it can be crucial for the identification of early-onset neurodegenerative disorders. This study aims to examine the ability of the Flexible Attention Test (FAT), a new computer-based test battery for detecting executive dysfunction of early-onset cognitive impairment and dementia patients.

METHOD

We analyzed the FAT subtask results in memory clinic patients with cognitive symptom onset at ≤65 years. The patients were divided into four groups: early onset dementia (EOD, n = 48), mild cognitive impairment due to neurological causes (MCI-n, n = 34), MCI due to other causes (MCI-o, n = 99), and subjective cognitive decline (SCD, n = 14). The test accuracy to distinguish EOD patients from other groups was examined, as well as correlations with pen-and-paper EF tests. We also reported the 12-months follow-up results.

RESULTS

The EOD and MCI-n patients performed significantly poorer (p ≤ .002) than those in the MCI-o and SCD groups in most of the FAT subtasks. The accuracies of the FAT subtasks to detect EOD from other causes were mainly moderate (0.34 ≤ area under the curve < 0.74). The FAT subtasks correlated logically with corresponding pen-and-paper EF tests (.15 ≤ r ≤ .75). No systematic learning effects were detected in the FAT performance at follow-up.

CONCLUSIONS

The FAT appears to be a promising method for the precise evaluation of EF and applicable distinguishing early-onset neurodegenerative disorders from patients with other causes of cognitive problems.

Progression trajectories from prodromal to overt synucleinopathies: a longitudinal, multicentric brain [18F]FDG-PET study

The phenoconversion trajectory from idiopathic/isolated Rapid eye movement (REM) sleep behavior disorder (iRBD) towards either Parkinson's Disease (PD) or Dementia with Lewy Bodies (DLB) is currently uncertain. We investigated the capability of baseline brain [18F]FDG-PET in differentiating between iRBD patients eventually phenoconverting to PD or DLB, by deriving the denovoPDRBD-related pattern (denovoPDRBD-RP) from 32 de novo PD patients; and the denovoDLBRBD-RP from 30 de novo DLB patients, both with evidence of RBD at diagnosis. To explore [18F]FDG-PET phenoconversion trajectories prediction power, we applied these two patterns on a group of 115 iRBD patients followed longitudinally. At follow-up (25.6 ± 17.2 months), 42 iRBD patients progressed through overt alpha-synucleinopathy (21 iRBD-PD and 21 iRBD-DLB converters), while 73 patients remained stable at the last follow-up visit (43.2 ± 27.6 months). At survival analysis, both patterns were significantly associated with the phenoconversion trajectories. Brain [18F]FDG-PET is a promising biomarker to study progression trajectories in the alpha-synucleinopathy continuum.

Cerebral artery and brain pathology correlates of antemortem cerebral artery 4D flow MRI

Large-scale clinical research studies often incorporate neuroimaging biomarkers to understand underlying pathologic changes that occur in aging and neurodegenerative disease and are associated with cognitive decline and clinical impairment. Of particular interest are neuroimaging methods designed to understand various aspects of cerebrovascular disease that can lead to dementia and also co-occur with neurodegenerative diseases such as Alzheimer's disease. Neurovascular 4D flow magnetic resonance imaging is one such method that measures hemodynamic characteristics of medium-large cerebral vessels, but it remains unclear how measures derived from 4D flow imaging including pulsatility index, cerebral blood flow, and cross-sectional area relate to underlying pathologic changes in cerebral arteries and downstream cerebrovascular pathology. For example, pulsatility index is thought to be a marker of vessel compliance, which may be due to fibrotic and/or atherosclerotic changes. This observational study investigates imaging-pathologic correlates of cerebral artery 4D flow MRI in 20 initial brain donors (mean (SD) age at death 78.2 (10.3) years; 3.2 (1.4) years from MRI to autopsy) from the Wisconsin Alzheimer's Disease Research Center that underwent antemortem imaging and postmortem assessment of cerebral artery and brain pathology to identify possible pathologic correlates of 4D flow MRI. Our results suggest that 4D flow MRI measures recapitulate expected hemodynamic and structural relationships across cerebral arteries, but also that measures like MRI cross-sectional area may reflect arterial fibrosis whereas mean blood flow may indicate downstream cerebrovascular disease including white matter rarefaction and arteriolosclerosis. In contrast, associations were minimal with pulsatility index and cerebral artery or brain pathology across participants but were moderate across arterial segments. To our knowledge, this is the first study to investigate pathologic correlates of antemortem 4D flow MRI in cerebral arteries. These results provide preliminary insights regarding the pathologic processes contributing to cerebral artery hemodynamics measured with 4D flow MRI that will help inform interpretation of large-scale clinical aging and dementia studies utilizing this method. Future work with larger samples is needed to confirm these findings.