Risk factors for dementia with Lewy bodies: a case-control study

Relationship Between Depression and Neurodegeneration: Risk Factor, Prodrome, Consequence, or Something Else? A Scoping Review

Background: The link between depression and neurodegeneration is complex and unclear. It is debated whether depression is a risk factor, a prodrome, a consequence, or unrelated. Objectives: This review examines these possibilities to clarify their connection, focusing primarily on Alzheimer's disease, vascular dementia, Parkinson's disease, and other highly comorbid neurodegenerative diseases. Methods: Eligibility criteria: The studies included in this review focused on neurodegenerative diseases with high comorbidity with depression, published in peer-reviewed English-language journals, providing empirical evidence on the link between the two conditions or theoretical frameworks that point to other studies. Non-human studies and those irrelevant to this connection were excluded. Source of evidence: AI-supported tools identified relevant articles. Results: Most studies suggest depression may contribute to neurodegeneration, but clinical, neuroimaging, and longitudinal evidence also support its role as a prodrome or consequence, indicating a bidirectional relationship. Conclusions: Despite extensive research, the connection remains unclear, highlighting the need for further investigation into underlying mechanisms and interdependencies, focusing on longitudinal studies by examining causality.

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

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

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

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

Sex Differences for Social Determinants Associated with Lewy Body Dementia Onset and Diagnosis

INTRODUCTION

Multiple studies report sex and gender differences in Lewy body dementia (LBD); however, there is a paucity of research investigating social determinants associated with LBD.

METHODS

Participants with LBD (51 females, 79 males) and controls with similar age (64 females, 60 males) completed remote surveys assessing various social and demographic variables, and age at LBD onset for LBD group. Sex-stratified comparisons for LBD and control groups, and comparisons of females and males with LBD were done for social determinants. Sex differences for onset age were further analyzed with linear models adjusting for significantly differing social variables between the sexes.

RESULTS

LBD group had lower years of education, income, subjective social status than controls, with larger differences for males than females (p < 0.05 for all). Higher percentage of females with LBD was living alone (p = 0.016) and not married/partnered (p = 0.002) compared to males with LBD. Adjusting for social variables that differed between the sexes, females were younger at cognitive impairment onset (p = 0.037) and diagnosis (p = 0.032). For the overall cohort, being ethnoracial minoritized, sexual and gender minoritized, and having lower education quality were associated with younger age at symptom onset (p < 0.049 for all). For females, lower childhood subjective social status (p = 0.037), and for males, being ethnoracial minoritized (p < 0.001) and lower years of education (p = 0.031) were associated with younger age at diagnosis.

CONCLUSION

Social determinants, even during childhood, can impact the LBD onset differently for females and males. Interactions between biological and social factors need to be investigated further with inclusive and diverse cohorts in LBD.

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.

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.

Adult Attention Deficit-Hyperactivity Disorder is associated with Lewy Body Disease and Cognitive Impairment: A prospective cohort Study With 15-year Follow-Up

OBJECTIVES

Past reports have suggested that attention-deficit/hyperactivity disorder (ADHD) may be a risk factor for Lewy body disease (LBD). To confirm this relationship, we conducted the present study.

DESIGN

A prospective observational cohort study with a follow-up to 15 years.

SETTING

The subjects were recruited from cognitive neurology clinics, where they attended for a cognitive complaint or health check-up.

PARTICIPANTS

Two groups of subjects: ADHD adults and healthy subjects.

MEASUREMENTS

The risk of dementia and LBD was estimated with Kaplan-Meier analysis comparing for the presence or absence of ADHD with the log-rank test. Predictors of conversion were assessed through separate univariate and multivariate Cox regression analyses, adjusting for several variables.

RESULTS

The baseline sample consisted of 161 subjects with ADHD and 109 without ADHD. At the end of the follow-up, 31 subjects developed dementia, 27 cases in the ADHD group and 4 in comparison group. Dementia with Lewy bodies (DLB) was the most frequent type (N:20) of which 19 corresponded to the ADHD group. The incidence of non-amnestic-MCI in the ADHD group was higher representing 67.1 % of these subjects (N:108), and 17.4% (N:19) of healthy cases. The hazard ratios for dementia and LBD in the multivariate adjusted model were 3.33 (95% CI 1.0915 to 10.1699) and 54.54 (95% CI 7.4849 to 397.5028), respectively in the ADHD group.

CONCLUSIONS

This study showed that adult ADHD is independently associated with an increased risk of LBD, dementia, and na-MCI. Future studies should clarify this relationship to develop preventive measures for these patients.

Risk factors for the neurodegenerative dementias in the Western Pacific region

The Western Pacific Region (WPR) is characterized by a group of socioeconomically, culturally, and geopolitically heterogenous countries and represents a microcosm of the global endemic of neurodegeneration. This review will chart the known risk factors for dementia across the WPR. We explore the intersection between the established risk factors for dementia including the biomedical and lifestyle (cardiovascular and metabolic disease, sleep, hearing loss, depression, alcohol, smoking, traumatic brain injury, genetics) and social determinants (social disadvantage, limited education, systemic racism) as well as incorporate neuroimaging data, where available, to predict disease progression in the WPR. In doing so, we highlight core risk factors for dementia in the WPR, as well as geographical epicentres at heightened risk for dementia, to orient future research towards addressing these disparities.

Environmental risk factors provoke new thinking for prevention and treatment of dementia with Lewy bodies

In recent years, environmental factors have received attention in the pathogenesis of neurodegenerative diseases. Other than genetic factors, the identification of environmental factors and modifiable risk factors may create opportunities to delay the onset or slow the progression of Lewy body disease. Researchers have made significant progress in understanding environmental and modifiable risk factors over the past 30 years. To date, despite the increasing number of articles assessing risk factors for Lewy body disease, few reviews have focused on their role in its onset. In this review, we reviewed the literature investigating the relationship between Lewy body disease and several environmental and other modifiable factors. We found that some air pollutants, exposure to some metals, and infection with some microorganisms may increase the risk of Lewy body disease. Coffee intake and the Mediterranean diet are protective factors. However, it is puzzling that low educational levels and smoking may have some protective effects. In addition, we proposed specific protocols for subsequent research directions on risk factors for neurodegenerative diseases and improved methods. By conducting additional case-control studies, we could explore the role of these factors in the etiopathogenesis of Lewy body disease, establishing a foundation for strategies aimed at preventing and reducing the onset and burden of the disease.

Moderate coffee or tea consumption decreased the risk of cognitive disorders: an updated dose-response meta-analysis

CONTEXT

Although several epidemiological studies have examined the association between coffee or tea intake and the risk of cognitive disorders, the results to date are inconsistent.

OBJECTIVE

An updated systematic review and dose-response meta-analysis was conducted to confirm the association between coffee, tea, and caffeine consumption and the risk of cognitive disorders.

DATA SOURCES

PubMed, Embase, and Web of Science were searched from inception to January 2022 for relevant studies, including dementia, Alzheimer disease (AD), and cognitive impairment or decline.

DATA EXTRACTION

Two reviewers independently performed data extraction and assessed the study quality.

DATA ANALYSIS

Restricted cubic splines were used to conduct the dose-response meta-analysis for coffee and tea intake.

RESULTS

Twenty-two prospective studies and 11 case-control studies involving 389 505 participants were eligible for this meta-analysis. Coffee and tea consumption was linked to a lower risk of cognitive disorders, with an overall relative risk (RR) of 0.73 (95% CI: 0.60-0.86) and 0.68 (95% CI: 0.56-0.80), respectively. The subgroup analysis revealed that ethnicity, sex, and outcomes had significant effects on this association. Protection was stronger for men than that for women in both coffee and tea consumption. A nonlinear relationship was found between coffee consumption and AD risk, and the strength of protection peaked at approximately 2.5 cups/day (RR: 0.74; 95% CI: 0.59-0.93). A linear relationship was found between tea consumption and cognitive disorders, and the risk decreased by 11% for every 1-cup/day increment.

CONCLUSION

This meta-analysis demonstrated that the consumption of 2.5 cups coffee/day minimizes the risk of AD, and 1 cup/day of tea intake leads to an 11% reduction in cognitive deficits. Effective interventions involving coffee and tea intake might prevent the occurrence of dementia.

Involvement of ApoE4 in dementia with Lewy bodies in the prodromal and demented stages: evaluation of the Strasbourg cohort

ApoE4 as a risk factor for dementia with Lewy bodies (DLB) is still an issue. We sought to determine the involvement of ApoE4 according to different clinical parameters in our cohort of patients from Strasbourg, France. ApoE genotyping was performed on the AlphaLewyMA cohort. In this cohort, 197 patients were genotyped: 105 DLB patients, 37 Alzheimer's disease (AD) patients, 29 patients with AD/DLB comorbidity, and 26 control subjects (CS). The groups of patients were also classified according to the stage of evolution of the disease: prodromal or demented. We analyzed other parameters in relation to ApoE4 status, such as years of education (YOE) and Alzheimer CSF biomarkers. We observed a higher proportion of ApoE4 carriers in the AD (51.4%) and AD/DLB (72.4%) groups compared to the DLB (25.7%) and CS (11.5%) groups (p < 0.0001). We found a correlation between age at disease onset and YOE in the AD group (p = 0.039) but not in the DLB group (p = 0.056). Interestingly, in the DLB group, the subgroup of patients with high YOE (≥ 11) had significantly more patients with ApoE4 than the subgroup with low YOE (< 11). AD biomarkers did not seem to be impacted by the presence of ApoE4, except for Aβ42: DLB ApoE4-positive demented patients showed a more marked Aβ42 decrease. ApoE4 does not appear to be a risk factor for "pure" DLB patients. These results suggest a strong link between ApoE4 and amyloidopathy and consequently with AD. Trial registration: AlphaLewyMa, Identifier: NCT01876459, date of registration: June 12, 2013.

Genetic analysis of the X chromosome in people with Lewy body dementia nominates new risk loci

Sex influences the prevalence and symptoms of Lewy body dementia (LBD). However, genome-wide association studies typically focus on autosomal variants and exclude sex-specific risk factors. We addressed this gap by performing an X chromosome-wide association study using whole-genome sequence data from 2591 LBD cases and 4391 controls. We identified a significant risk locus within intron 1 of MAP3K15 (rs141773145, odds ratio = 2.42, 95% confidence interval = 1.65-3.56, p-value = 7.0 × 10-6) in female LBD cases conditioned for APOE ε4 dosage. The locus includes an enhancer region that regulates MAP3K15 expression in ganglionic eminence cells derived from primary cultured neurospheres. Rare variant burden testing showed differential enrichment of missense mutations in TEX13A in female LBD cases, that did not reach significance (p-value = 1.34 × 10-4). These findings support the sex-specific effects of genetic factors and a potential role of Alzheimer's-related risk for females with LBD.

Elevated serum LDL-C increases the risk of Lewy body dementia: a two-sample mendelian randomization study

BACKGROUND

Lewy body dementia (LBD) ranks second among prevalent neurodegenerative dementias. Previous studies have revealed associations of serum lipid measures with several neurodegenerative diseases. Nevertheless, the potential connection between serum lipids and LBD remains undetermined. In this study, Mendelian randomization (MR) analyses were carried out to assess the causal relationships of several serum lipid measures with the risk of developing LBD.

METHODS

Genome-wide association study (GWAS) data for serum lipids and LBD in European descent individuals were acquired from publicly available genetic summary data. A series of filtering procedures were conducted to identify the genetic variant candidates that are related to serum lipids, including high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), and triglycerides (TG). The causal effects were primarily determined through inverse-variance weighting (IVW)-based analyses.

RESULTS

Neither TG (odds ratio [OR] = 1.149; 95% confidence interval [CI], 0.887-1.489; P = 0.293) nor HDL-C (OR = 0.864; 95% CI, 0.718-1.041; P = 0.124) had causal effects on LBD. However, a causal relationship was identified between LDL-C and LBD (OR = 1.343; 95% CI, 1.094-1.649; P = 0.005), which remained significant (OR = 1.237; 95% CI, 1.015-1.508; P = 0.035) following adjustment for HDL-C and TG in multivariable MR.

CONCLUSIONS

Elevated serum LDL-C increases the risk of LBD, while HDL-C and TG have no significant causal effects on LBD.

Investigating the association between a history of depression and biomarkers of Alzheimer's disease, cerebrovascular disease, and neurodegeneration in patients with dementia

The association between depression and dementia, particularly Alzheimer's disease (AD) and cerebrovascular disease (CVD), remains an active area of research. This study aimed to investigate the relationship between a history of depression and biomarkers of AD and CVD in patients with dementia in a clinical setting. A total of 126 patients from the University Health Network (UHN) Memory Clinic with comprehensive clinical evaluations, including neuropsychological testing and medical examinations, were included. Lumbar puncture was performed to collect cerebrospinal fluid (CSF) for biomarker analysis, and brain magnetic resonance imaging (MRI) scans were obtained to assess white matter hyperintensity (WMH) burden. The presence of depression was determined through medical records. The study findings did not reveal significant differences between participants with and without a history of depression in terms of AD biomarkers, WMH burden, neurofilament light chain levels, cognitive scores, age of symptom onset, disease duration, or vascular risk scores. Logistic regression analysis did not indicate a meaningful predictive value of these variables for depression status. This clinical study contributes to our understanding regarding the association between depression and AD/CVD biomarkers in patients with cognitive impairment. Further research is needed to elucidate the complex relationship between depression and dementia and to explore the potential mechanisms linking depression, AD, and CVD.

Plasma metabolites distinguish dementia with Lewy bodies from Alzheimer's disease: a cross-sectional metabolomic analysis

Background

In multifactorial diseases, alterations in the concentration of metabolites can identify novel pathological mechanisms at the intersection between genetic and environmental influences. This study aimed to profile the plasma metabolome of patients with dementia with Lewy bodies (DLB) and Alzheimer's disease (AD), two neurodegenerative disorders for which our understanding of the pathophysiology is incomplete. In the clinical setting, DLB is often mistaken for AD, highlighting a need for accurate diagnostic biomarkers. We therefore also aimed to determine the overlapping and differentiating metabolite patterns associated with each and establish whether identification of these patterns could be leveraged as biomarkers to support clinical diagnosis.

Methods

A panel of 630 metabolites (Biocrates MxP Quant 500) and a further 232 metabolism indicators (biologically informative sums and ratios calculated from measured metabolites, each indicative for a specific pathway or synthesis; MetaboINDICATOR) were analyzed in plasma from patients with probable DLB (n = 15; age 77.6 ± 8.2 years), probable AD (n = 15; 76.1 ± 6.4 years), and age-matched cognitively healthy controls (HC; n = 15; 75.2 ± 6.9 years). Metabolites were quantified using a reversed-phase ultra-performance liquid chromatography column and triple-quadrupole mass spectrometer in multiple reaction monitoring (MRM) mode, or by using flow injection analysis in MRM mode. Data underwent multivariate (PCA analysis), univariate and receiving operator characteristic (ROC) analysis. Metabolite data were also correlated (Spearman r) with the collected clinical neuroimaging and protein biomarker data.

Results

The PCA plot separated DLB, AD and HC groups (R2 = 0.518, Q2 = 0.348). Significant alterations in 17 detected metabolite parameters were identified (q ≤ 0.05), including neurotransmitters, amino acids and glycerophospholipids. Glutamine (Glu; q = 0.045) concentrations and indicators of sphingomyelin hydroxylation (q = 0.039) distinguished AD and DLB, and these significantly correlated with semi-quantitative measurement of cardiac sympathetic denervation. The most promising biomarker differentiating AD from DLB was Glu:lysophosphatidylcholine (lysoPC a 24:0) ratio (AUC = 0.92; 95%CI 0.809-0.996; sensitivity = 0.90; specificity = 0.90).

Discussion

Several plasma metabolomic aberrations are shared by both DLB and AD, but a rise in plasma glutamine was specific to DLB. When measured against plasma lysoPC a C24:0, glutamine could differentiate DLB from AD, and the reproducibility of this biomarker should be investigated in larger cohorts.

Which factors affect phenoconversion in isolated rapid eye movement sleep behavior disorder?

AIM

Isolated REM sleep behavior disorder (IRBD) is characterized by loss of the normal atonia of REM sleep. Patients with IRBD are at substantial risk of developing the synuclein-related neurodegenerative diseases (NDD). Few predictors of phenoconversion (from IRBD to NDD) have been identified such as age >65 years, hyposmia, constipation, elevated Epworth sleepiness scale (ESS). We aimed to detect rate and risk factors of phenoconversion.

METHOD

The study designed as retrospectively. NDD was developed in 18 (27.27%) patients while NDD wasn't developed in 48 (72.73%) patients after ten years. The data of the first visit (age, gender, hyposmia, constipation, ESS, comorbidities, physical/neurological examinations, laboratory, and polysomnography) were compared between NDD (n:18) and IRBD (46) groups. The statistical program IBM SPSS Statistics Version 20.0 was used for all analyzes. The threshold for statistical significance for each test was set at 0.05.

RESULTS

Although, most first-visit data (age, gender, hyposmia, constipation, ESS, laboratory, polysomnography) were not different between NDD (n:18) and IRBD (n:48) groups, diabetes mellitus (DM) frequency (p:0.021), mean duration of DM (0.027), chest circumference (p:0.017), and hip circumference (p:0.045) were found higher in NDD than IRBD. If the risk of phenoconversion calculated by logistic regression analysis was different only in terms of DM frequency (p:0.030) [odds ratio: 4.909 (1.17-20.19)].

CONCLUSION

The present study showed that the phenoconversion rate for ten years is 27.27%, and IRBD patients with diabetes mellitus increase the phenoconversion risk nearly five times.

Misfolded α-Synuclein in Cerebrospinal Fluid of Contact Sport Athletes

BACKGROUND

Misfolded α-synuclein in Parkinson's disease (PD) and dementia with Lewy bodies (DLB) can be detected using the real-time quaking-induced conversion (RT-QuIC) technique in cerebrospinal fluid (CSF).

OBJECTIVES

The objectives are (1) to examine misfolded CSF α-synuclein incidence, and (2) to compare clinical presentation, sports history, brain volumes, and RT-QuIC α-synuclein positivity in former athletes.

METHODS

Thirty former athletes with magnetic resonance imaging, neuropsychological testing, and CSF analyzed for phosphorylated tau 181 (p-tau), total tau (t-tau), amyloid-β 42 (Aβ42), and neurofilament light chain (NfL). CSF α-synuclein was detected using RT-QuIC.

RESULTS

Six (20%) former athletes were α-synuclein positive. α-Synuclein positive athletes were similar to α-synuclein negative athletes on demographics, sports history, clinical features, CSF p-tau, t-tau, Aβ42, and NfL; however, had lower grey matter volumes in the right inferior orbitofrontal, right anterior insula and right olfactory cortices.

CONCLUSIONS

α-Synuclein RT-QuIC analysis of CSF may be useful as a prodromal biofluid marker of PD and DLB. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Disparity of smell tests in Alzheimer's disease and other neurodegenerative disorders: a systematic review and meta-analysis

Background

There are discrepancies of olfactory impairment between Alzheimer's disease (AD) and other neurodegenerative disorders. Olfactory deficits may be a potential marker for early and differential diagnosis of AD. We aimed to assess olfactory functions in patients with AD and other neurodegenerative disorders, to further evaluate the smell tests using subgroup analysis, and to explore moderating factors affecting olfactory performance.

Methods

Cross-sectional studies relating to olfactory assessment for both AD and other neurodegenerative disorders published before 27 July 2022 in English, were searched on PubMed, Embase and Cochrane. After literature screening and quality assessment, meta-analyses were conducted using stata14.0 software.

Results

Forty-two articles involving 12 smell tests that evaluated 2,569 AD patients were included. It was revealed that smell tests could distinguish AD from mild cognitive impairment (MCI), Lewy body disease (LBD), depression, and vascular dementia (VaD), but not from diseases such as frontotemporal dementia (FTD). Our finding indicated that in discriminating AD from MCI, the University of Pennsylvania Smell Identification Test (UPSIT) was most frequently used (95%CI: -1.12 to -0.89), while the Brief Smell Identification Test (B-SIT), was the most widely used method in AD vs. LBD group. Further subgroup analyses indicated that the methods of smell test used contributed to the heterogeneity in olfactory threshold and discrimination scores in group AD vs. MCI. While the moderating variables including age, MMSE scores, education years in AD vs. LBD, were account for heterogeneity across studies.

Conclusion

Our finding suggests smell tests have potential value in early differential diagnosis of AD. UPSIT and its simplified variant, B-SIT, are widely used methods in the analyses.

Systematic Review Registration

https://www.crd.york.ac.uk/PROSPERO/display_record.php? RecordID = 357970 (PROSPERO, registration number CRD42022357970).

Sex differences in alpha-synucleinopathies: a systematic review

Background

Past research indicates a higher prevalence, incidence, and severe clinical manifestations of alpha-synucleinopathies in men, leading to a suggestion of neuroprotective properties of female sex hormones (especially estrogen). The potential pathomechanisms of any such effect on alpha-synucleinopathies, however, are far from understood. With that aim, we undertook to systematically review, and to critically assess, contemporary evidence on sex and gender differences in alpha-synucleinopathies using a bench-to-bedside approach.

Methods

In this systematic review, studies investigating sex and gender differences in alpha-synucleinopathies (Rapid Eye Movement (REM) Behavior Disorder (RBD), Parkinson's Disease (PD), Dementia with Lewy Bodies (DLB), Multiple System Atrophy (MSA)) from 2012 to 2022 were identified using electronic database searches of PubMed, Embase and Ovid.

Results

One hundred sixty-two studies were included; 5 RBD, 6 MSA, 20 DLB and 131 PD studies. Overall, there is conclusive evidence to suggest sex-and gender-specific manifestation in demographics, biomarkers, genetics, clinical features, interventions, and quality of life in alpha-synucleinopathies. Only limited data exists on the effects of distinct sex hormones, with majority of studies concentrating on estrogen and its speculated neuroprotective effects.

Conclusion

Future studies disentangling the underlying sex-specific mechanisms of alpha-synucleinopathies are urgently needed in order to enable novel sex-specific therapeutics.

Reduced and Delayed Cerebrovascular Reactivity in Patients with Parkinson's Disease

BACKGROUND

Cerebrovascular dysfunction in Parkinson's disease (PD) is heterogeneous and may contribute to disease pathophysiology or progression. There is a need to understand the mechanisms by which cerebrovascular dysfunction is altered in participants with PD.

OBJECTIVES

The objective of this study is to test the hypothesis that participants with PD exhibit a significant reduction in the ability of the cerebral vessels to dilate in response to vasoactive challenges relative to healthy controls (HC).

METHODS

The current study uses a vasodilatory challenge while participants undergo functional magnetic resonance imaging to quantify the amplitude and delay of cerebrovascular reactivity in participants with PD relative to age and sex-matched HC. An analysis of covariance was used to evaluate differences in cerebrovascular reactivity amplitude and latency between PD participants and HC.

RESULTS

A significant main effect of group was observed for whole-brain cerebrovascular reactivity amplitude (F(1, 28)  = 4.38, p = 0.046, Hedge's g = 0.73) and latency (F(1, 28)  = 16.35, p < 0.001, Hedge's g = 1.42). Participants with PD exhibited reduced whole-brain amplitude and increased latencies in cerebrovascular reactivity relative to HC. The evaluation of regional effects indicates that the largest effects were observed in the cuneus, precuneus, and parietal regions.

CONCLUSIONS

PD participants exhibited reduced and delayed cerebrovascular reactivity. This dysfunction may play an important role in chronic hypoxia, neuroinflammation, and protein aggregation, mechanisms that could lead to disease progression. Cerebrovascular reactivity may serve as an important biomarker and target for future interventions. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Examining the Lancet Commission risk factors for dementia using Mendelian randomisation

BACKGROUND

Dementia incidence is increasing across the globe and currently there are no disease-modifying pharmaceutical treatments. The Lancet Commission on dementia identified 12 modifiable risk factors which explain 40% of dementia incidence. However, whether these associations are causal in nature is unclear.

OBJECTIVE

To examine the modifiable risk factors for dementia as identified in the Lancet Commission review using Mendelian randomisation (MR) to establish if, based on genetic evidence, these associations with different dementia subtypes are causal in nature.

METHODS

Publicly available genome-wide association study data were used for 10 risk factors and Alzheimer's disease (AD), frontotemporal dementia and dementia with Lewy bodies. Two-sample MR using the inverse varianceweighted method was conducted to test for causal relationships. Weighted median MR and MR-Egger were used to test for pleiotropic effects.

RESULTS

Genetic proxied risk for higher levels of smoking (OR: 0.80 (95% CI: 0.69; 0.92), p=0.002), obesity (OR: 0.87 (95% CI: 0.82; 0.92), p<0.001) and blood pressure (OR: 0.90 (95% CI: 0.82; 0.99), p=0.035) appeared to be protective against the risk of AD. Post hoc analyses indicated these associations had pleiotropic effects with the risk of coronary artery disease. Genetic proxied risk of educational attainment was found to be inconsistently associated with the risk of AD.

CONCLUSIONS AND IMPLICATIONS

Post hoc analysis indicated that the apparent protective effects of smoking, obesity and blood pressure were a result of survivor bias. The findings from this study did not support those presented by the Lancet Commission. Evidence from causal inference studies should be considered alongside evidence from epidemiological studies and incorporated into reviews of the literature.

Race and Ethnicity in Lewy Body Dementia: A Narrative Review

Lewy body dementia is the third most common and costliest type of dementia. It is an umbrella term for dementia with Lewy bodies and Parkinson's disease dementia, both of which place a substantial burden on the person and society. Recent findings outline ethnoracial differences in dementia risk. Delayed and misdiagnosis across ethnoracial groups contribute to higher levels of burden. In this context, we aimed to summarize current knowledge, gaps, and unmet needs relating to race and ethnicity in Lewy body dementia. In this narrative review, we provide an overview of studies on Lewy body dementia focusing on differences across ethnoracial groups and outline several recommendations for future studies. The majority of the findings comparing different ethnoracial groups were from North American sites. There were no differences in clinical prevalence and progression across ethnoracial groups. Compared to people identifying as non-Hispanic White, co-pathologies were more common and clinical diagnostic accuracy was lower for people identifying as Black. Co-morbidities (e.g., diabetes, hypertension) were more common and medication use rates (e.g., antidepressants, antiparkinsonian agents) were lower for people identifying as Black or Hispanic compared to people identifying as White. More than 90% of clinical trial participants identified as non-Hispanic White. Despite increasing efforts to overcome disparities in Alzheimer's disease and related dementias, inclusion of individuals from minoritized communities in Lewy body dementia studies continues to be limited and the findings are inconclusive. Representation of diverse populations is crucial to improve the diagnostic and therapeutic efforts in Lewy body dementia.

Urine caffeine metabolites are positively associated with cognitive performance in older adults: An analysis of US National Health and Nutrition Examination Survey (NHANES) 2011 to 2014

The aim of this study was to explore urine caffeine metabolites in relation to cognitive performance among 2011-2014 National Health and Nutrition Examination Survey participants aged ≥60 years. We hypothesized that urine caffeine metabolites were positively associated with cognition in older adults. Caffeine and 14 of its metabolites were quantified in urine by use of high-performance liquid chromatography-electrospray ionization-tandem quadruple mass spectrometry with stable isotope labeled internal standards. Cognitive assessment was based on scores from the word learning and recall modules. Participants were categorized based on the quartiles of caffeine and its metabolites level. The association between caffeine metabolites and each cognitive dimension was analyzed using multiple logistic regression analysis in adjusted models. Stratification analyses by gender were also performed. For CERAD test, there was a significant association between 1-methyluric acid (OR=0.62, 95% CI: 0.42 to 0.92), 7-methylxanthine(OR=0.49, 95% CI: 0.27 to 0.89), theophylline (OR=0.52, 95% CI: 0.29 to 0.92), as well as paraxanthine (OR=0.49, 95% CI: 0.27 to 0.88) and cognitive function. For animal fluency test, there was a positive association between theophylline (TP) (OR=0.44, 95% CI: 0.22 to 0.89) and cognitive function. The trend that the risk of low cognitive function decreased with increasing concentration of 1-methylxanthine (P trend=0.0229) was also observed. Furthermore, the same trend existed for 3-methylxanthine (p trend = 0.0375) in men. In conclusion, there was a significant positive association between urine caffeine metabolites and cognitive performance in older adults, particularly for theophylline, paraxanthine and caffeine; and the association might be dependent on gender.

MED13 and glycolysis are conserved modifiers of α-synuclein-associated neurodegeneration

α-Synuclein (α-syn) is important in synucleinopathies such as Parkinson's disease (PD). While genome-wide association studies (GWASs) of synucleinopathies have identified many risk loci, the underlying genes have not been shown for most loci. Using Drosophila, we screened 3,471 mutant chromosomes for genetic modifiers of α-synuclein and identified 12 genes. Eleven modifiers have human orthologs associated with diseases, including MED13 and CDC27, which lie within PD GWAS loci. Drosophila Skd/Med13 and glycolytic enzymes are co-upregulated by α-syn-associated neurodegeneration. While elevated α-syn compromises mitochondrial function, co-expressing skd/Med13 RNAi and α-syn synergistically increase the ratio of oxidized-to-reduced glutathione. The resulting neurodegeneration can be suppressed by overexpressing a glycolytic enzyme or treatment with deferoxamine, suggesting that compensatory glycolysis is neuroprotective. In addition, the functional relationship between α-synuclein, MED13, and glycolytic enzymes is conserved between flies and mice. We propose that hypoxia-inducible factor and MED13 are part of a druggable pathway for PD.

Surgical Management of Synucleinopathies

Synucleinopathies represent a diverse set of pathologies with significant morbidity and mortality. In this review, we highlight the surgical management of three synucleinopathies: Parkinson's disease (PD), dementia with Lewy bodies (DLB), and multiple system atrophy (MSA). After examining underlying molecular mechanisms and the medical management of these diseases, we explore the role of deep brain stimulation (DBS) in the treatment of synuclein pathophysiology. Further, we examine the utility of focused ultrasound (FUS) in the treatment of synucleinopathies such as PD, including its role in blood-brain barrier (BBB) opening for the delivery of novel drug therapeutics and gene therapy vectors. We also discuss other recent advances in the surgical management of MSA and DLB. Together, we give a diverse overview of current techniques in the neurosurgical management of these pathologies.

Biomarkers of Dementia with Lewy Bodies: Differential Diagnostic with Alzheimer's Disease

Dementia with Lewy Bodies (DLB) is a common form of cognitive neurodegenerative disease. Only one third of patients are correctly diagnosed due to the clinical similarity mainly with Alzheimer’s disease (AD). In this review, we evaluate the interest of different biomarkers: cerebrospinal fluid (CSF), brain MRI, FP-CIT SPECT, MIBG SPECT, PET by focusing more specifically on differential diagnosis between DLB and AD. FP-CIT SPECT is of high interest to discriminate DLB and AD, but not at the prodromal stage (i.e., MCI). MIBG SPECT with decreased cardiac sympathetic activity, perfusion SPECT with occipital hypoperfusion, FDG PET with occipital hypometabolism and cingulate island signs are of interest at the dementia stage but with a lower validity. Brain MRI has shown differences in group study with lower grey matter concentration of the Insula in prodromal DLB, but its interest in clinical routines is not demonstrated. Concerning CSF biomarkers, many studies have already examined the relevance of AD biomarkers but also alpha-synuclein assays in DLB, so we will focus as comprehensively as possible on other biomarkers (especially those that do not appear to be directly related to synucleinopathy) that may be of interest in the differential diagnosis between AD and DLB. Furthermore, we would like to highlight the growing interest in CSF synuclein RT-QuIC, which seems to be an excellent discrimination tool but its application in clinical routine remains to be demonstrated, given the non-automation of the process.

Caffeine Consumption and Dementia: Are Lewy Bodies the Link?

OBJECTIVE

The objective of this study was to examine the association between caffeine intake and cognitive impairment. Caffeine-neuropathology correlations and interactions with lifestyle and genetic factors impacting caffeine metabolism and response were also tested.

METHODS

We included 888 participants aged 59+ years from the Rush Memory and Aging Project (MAP) and 303,887 participants aged 55+ years from the UK Biobank (UKB). MAP participants took part in annual cognitive testing. Diagnosis of dementia was based on clinical neurological examination and standardized criteria. A subset provided postmortem tissue for neuropathologic evaluation for common age-related diseases (eg, Alzheimer's disease [AD], Lewy bodies, and vascular). For UKB, dementia was determined by linked hospital and death records. Self-reported caffeine intake was estimated using food-frequency questionnaires in both cohorts. Cox proportional hazard ratio (HR), regression, and mixed models were used to examine associations of caffeine intake with incident dementia, cognitive decline, and neuropathology.

RESULTS

In MAP, compared to ≤100 mg/day, caffeine intake >100 mg/day was associated with a significantly higher HR (95% confidence interval [CI]) of all-cause (HR = 1.35, 95% CI = 1.03-1.76) and AD (HR = 1.41, 95% CI = 1.07-1.85) dementia. Caffeine intake was not associated with cognitive decline. In UKB, compared to ≤100 mg/day, the HRs (95% CI) of all-cause dementia for consuming 100 ≤ 200, 200 ≤ 300, 300 ≤ 400, and > 400 mg/day were 0.83 (95% CI = 0.72-0.94), 0.74 (95% CI = 0.64-0.85), 0.74 (95% CI = 0.64-0.85), and 0.92 (95% CI = 0.79-1.08), respectively. Similar results were observed for Alzheimer's dementia. In MAP, caffeine intake was inversely associated with postmortem Lewy bodies but no other age-related pathologies. Caffeine intake >100 mg/day was associated with lower neocortical type Lewy bodies (odds ratio (95%CI): 0.40 (95% CI = 0.21-0.75).

INTERPRETATION

Caffeine intake was inconsistently associated with clinical dementia; potentially explained by cohort differences in underlying dementia etiology. Lewy bodies may link caffeine to lower risk in some persons. ANN NEUROL 2022;91:834-846.

Biomarkers and diagnosis of dementia with Lewy bodies including prodromal: Practical aspects

Dementia with Lewy Bodies (DLB) is a common form of cognitive neurodegenerative disease. More than half of the patients affected are not or misdiagnosed because of the clinical similarity with Alzheimer's disease (AD), Parkinson's disease but also psychiatric diseases such as depression or psychosis. In this review, we evaluate the interest of different biomarkers in the diagnostic process: cerebrospinal fluid (CSF), brain MRI, FP-CIT SPECT, MIBG SPECT, perfusion SPECT, FDG-PET by focusing more specifically on differential diagnosis between DLB and AD. FP-CIT SPECT is of high interest to discriminate DLB and AD, but not at the prodromal stage. Brain MRI has shown differences in group study with lower grey matter concentration of the Insula in prodromal DLB, but its interest in clinical routine is not demonstrated. Among the AD biomarkers (t-Tau, phospho-Tau₁₈₁, Aβ42 and Aβ40) used routinely, t-Tau and phospho-Tau₁₈₁ have shown excellent discrimination whatever the clinical stages severity. CSF Alpha-synuclein assay in the CSF has also an interest in the discrimination between DLB and AD but not in segregation between DLB and healthy elderly subjects. CSF synuclein RT-QuIC seems to be an excellent biomarker but its application in clinical routine remains to be demonstrated, given the non-automation of the process.

Cause of Death Determined by Full-body Autopsy in Neuropathologically Diagnosed Dementias: The Biobank for Aging Studies of the University of Sao Paulo (BAS-USP), Brazil

OBJECTIVE

This study aimed to compare causes of death in the most prevalent neuropathologically diagnosed dementias.

METHODS

We analyzed causes of death in a community-based cohort of participants aged 50 or older, submitted to full-body autopsy and a comprehensive neuropathologic examination of the brain. Individuals with Alzheimer disease (AD), vascular dementia (VaD), mixed dementia (AD+VaD), or dementia with Lewy bodies (DLBs) were compared with individuals with no dementia.

RESULTS

In a sample of 920 individuals, 456 had no dementia, 147 had AD, 120 had VaD, 53 had DLB, and 37 had AD+VaD. Pneumonia as the cause of death was more frequent in the AD (P=0.023), AD+VaD (P=0.046), and DLB (P=0.043) groups. In addition, VaD (P=0.041) and AD+VaD (P=0.028) groups had a higher frequency of atherosclerosis as detected by full-body autopsy.

CONCLUSION

Our findings highlight the importance of preventive measures regarding atherosclerosis and pneumonia in patients with dementia. Moreover, because of cognitive impairment, these patients may not fully account for symptoms to make early detection and diagnosis possible. These results confirm findings from previous studies that were based on clinical data, with added accuracy provided by neuropathologic diagnosis and full-body autopsy reports.

Lewy body dementia is associated with an increased risk of atrial fibrillation: A case-control study

BACKGROUND

Lewy bodies are a hallmark of Dementia with Lewy Bodies. They can also be found in the sinoatrial node and may be associated with heart disease.

OBJECTIVES

We aimed to investigate a possible association between Lewy Body dementia and atrial fibrillation.

METHODS

We performed a case-control study based on our centre's cohort of degenerative dementia (Dementia with Lewy Bodies and Alzheimer's disease) patients. The possible association between Lewy Body dementia and atrial fibrillation was studied through a binomial logistic regression, which adjusted for comorbidity data.

RESULTS

We included 461 patients. 45 of the 398 (11.3%) with Alzheimer's disease and 14 of the 63 with Dementia with Lewy Bodies (22.2%) had atrial fibrillation. Heart failure (OR = 3.345, 95%CI = [1.618, 6.916], p = 0.001), hypertension (OR = 2.547, 95%CI = [1,137, 5.703], p = 0.023), stroke (OR = 2.274, 95%CI = [1.013, 5.103], p = 0.046) and Dementia with Lewy Bodies (OR = 2.536, 95%CI = [1.105, 5.822], p = 0.028) were associated with atrial fibrillation.

CONCLUSIONS

We found an association between Dementia with Lewy bodies and Atrial Fibrillation.

The vascular risk factors and vascular neuropathology in subjects with autopsy-confirmed dementia with Lewy bodies

BACKGROUND

The frequency of vascular risk factors (VRFs) and the relationship between vascular pathology and cognitive function in neurodegenerative disease remains incompletely understood.

OBJECTIVE

The purpose of this study was to describe the frequency of VRFs and vascular pathology and explore the relationship between vascular pathology and cognitive function in dementia with Lewy bodies (DLB).

METHODS

This study included 363 autopsy-confirmed DLB and 753 Alzheimer's disease (AD) patients from the National Alzheimer's Coordinating Center (NACC) database. We used chi-squared test and analysis of variance to compare the VRFs and related factors in DLB and AD. Multinomial logistic regression and Spearman's correlation test were used to examine the relationship between vascular pathology and cognitive function.

RESULTS

No significant differences of VRFs were identified between DLB and AD. Alzheimer's disease patients had higher rates of microinfarcts (23.5% vs. 16.3%, p = 0.005) and moderate to severe amyloid angiopathy (45.9% vs. 36.1%, p = 0.002). In DLB patients, only cerebral amyloid angiopathy (CAA) pathology was negatively correlated with memory domain (r = -0.263, p < 0.001) and language (r = -0.112,p = 0.034). The rates of APOE ε4 allele carriers (60.0% vs. 44.9%, p = 0.004) and CAA pathology (45.9% vs.23.4%, p < 0.001) were much higher in the group with an intermediate likelihood of DLB than in the group with a high likelihood. There was a negative correlation between CAA pathology and memory (logical memory) in the group with an intermediate likelihood of DLB.

CONCLUSION

No difference of VRFs was identified between autopsy-confirmed DLB and AD. Cerebral amyloid angiopathy was shown to be an important pathology in DLB, which specifically correlated with memory and language. The groups with high and intermediate likelihood of DLB differed in terms of CAA pathology, and CAA pathology may play an important role in the development of DLB.

Infectious Agents as Potential Drivers of α-Synucleinopathies

α-synucleinopathies, encompassing Parkinson's disease, dementia with Lewy bodies, and multiple system atrophy, are devastating neurodegenerative diseases for which available therapeutic options are scarce, mostly because of our limited understanding of their pathophysiology. Although these pathologies are attributed to an intracellular accumulation of the α-synuclein protein in the nervous system with subsequent neuronal loss, the trigger(s) of this accumulation is/are not clearly identified. Among the existing hypotheses, interest in the hypothesis advocating the involvement of infectious agents in the onset of these diseases is renewed. In this article, we aimed to review the ongoing relevant factors favoring and opposing this hypothesis, focusing on (1) the potential antimicrobial role of α-synuclein, (2) potential entry points of pathogens in regard to early symptoms of diverse α-synucleinopathies, (3) pre-existing literature reviews assessing potential associations between infectious agents and Parkinson's disease, (4) original studies assessing these associations for dementia with Lewy bodies and multiple system atrophy (identified through a systematic literature review), and finally (5) potential susceptibility factors modulating the effects of infectious agents on the nervous system. © 2022 International Parkinson and Movement Disorder Society.

Correlates of Conversion from Mild Cognitive Impairment to Dementia with Lewy Bodies: Data from the National Alzheimer's Coordinating Center

BACKGROUND

Many patients with dementia with Lewy bodies (DLB) miss out on the best standards of care and psychosocial support due to diagnostic delays or inaccuracies following symptom onset.

OBJECTIVE

This study seeks to identify baseline characteristics in individuals with mild cognitive impairment (MCI) that correlate with eventual conversion to DLB or Alzheimer's disease (AD).

METHODS

Baseline neuropsychological and neuropsychiatric data were analyzed in National Alzheimer's Coordinating Center participants who completed the Uniform Data Set between 2006 and 2020 and subsequently converted from MCI to DLB or AD (n = 1632).

RESULTS

Only 6% of participants with MCI converted to DLB. Among those who converted to DLB, multidomain amnestic MCI (aMCI) was the most common subtype at study entry. As part of logistic regression analyses, odds ratios (ORs) were estimated for conversion to DLB versus AD based on study-entry characteristics, adjusting for age, sex, education, and years to diagnosis. The strongest predictors of conversion to DLB (p≤0.0001) were nonamnestic MCI versus aMCI (OR 8.2, CI [5.0, 14]), multidomain MCI versus single-domain MCI (OR 2.7, CI [1.7. 4.2]), male sex (OR 4.2, CI [2.5, 7.1]), and presence of nighttime behaviors (OR 4.4 CI [2.8, 6.9]).

CONCLUSION

A diagnosis of prodromal DLB should be considered in individuals with MCI who present with prominent executive/visuospatial deficits, neuropsychiatric symptoms, and less memory impairment. Early diagnosis of DLB may guide treatment planning, including the avoidance of antipsychotic medications in patients who develop psychotic symptoms, caregiver support, and initiation of early treatment(s) once medications become available.

Characteristics of Early-Onset Dementia in Chiba Prefecture, Japan: A Multicenter Survey

INTRODUCTION

Early-onset dementia (EOD), defined as dementia onset before the age of 65 years, is relatively rare, but its social impacts are significant. This study aimed to characterize the diagnosis and clinical and social status of EOD subjects in the 11 dementia centers in Chiba Prefecture, Japan.

METHODS

A retrospective 1-year survey was conducted. Collected data included clinical diagnosis, age at onset, age at survey, neuropsychological test, family history, employment, and living status.

RESULTS

We identified 208 EOD subjects, including 123 (59.4%), 24 (11.6%), 21 (10.1%), 17 (8.2%), and 10 (4.8%) with Alzheimer's disease (AD), vascular dementia, frontotemporal lobar degeneration (FTLD), dementia with Lewy bodies/Parkinson's disease dementia, and alcohol-related dementia, respectively. The Mini-Mental State Examination (MMSE) score <24 was observed in 50-75% of patients and was not correlated with disease duration. Twenty-four (16.4%) subjects had positive family history of EOD. EOD subjects were at risk of early retirement, and 133 subjects lived with their family, in whom 64 (30.8%) lived with their child.

CONCLUSION

In dementia centers, AD, FTLD, and Lewy body dementia had relatively large proportion. Employment, economy, and social supports are urgently needed for EOD subjects and their family.

Magnetic Resonance Imaging in Stable Mild Cognitive Impairment, Prodromal Alzheimer's Disease, and Prodromal Dementia with Lewy Bodies

INTRODUCTION

Fifteen percent of people with mild cognitive impairment (MCI) will progress to dementia within 2 years. There is increasing focus on the evaluation of biomarkers which point towards the underlying pathology. This enables better prediction of clinical outcomes. Early diagnosis of the dementia subtype is crucial for appropriate management and accurate prognosis. The aim of this study was to compare MRI measures in stable mild cognitive impairment patients (stable-MCI), prodromal Alzheimer's disease (pro-AD), and prodromal dementia with Lewy bodies (pro-DLB).

METHODS

Out of 1,814 patients assessed in Essex memory clinic between 2002 and 2017, 424 had MCI at baseline with follow-up data. All patients underwent comprehensive clinical and cognitive assessment at each assessment. MRI scans were acquired at patients' baseline assessment, corresponding to the time of initial MCI clinical diagnosis. Patients were grouped according to their diagnosis at the end of follow-up. All baseline scans were visually rated according to established rating scales for medial temporal atrophy (MTA), global cortical atrophy (GCA), and white matter lesions (WMLs).

RESULTS

MRI scans were available for 28 pro-DLB patients and were matched against 27 pro-AD and 28 stable-MCI patients for age, sex, and education. The mean follow-up duration was 34 months for the pro-AD group, 27 months for the pro-DLB group, and 21 months for the stable-MCI group. MTA scores were significantly greater in pro-AD patients compared to pro-DLB (p = 0.047) and stable-MCI patients (p = 0.012). There was no difference on GCA or WMLs between pro-AD, pro-DLB, and stable-MCI.

CONCLUSIONS

This study indicates that a simple visual rating of MTA at the stage of MCI already differs at a group level between patients that progress to AD, DLB, or continue to be stable-MCI. This could aid clinicians to differentiate between MCI patients who are likely to develop AD, versus those who might progress to DLB or remain stable.

Family History is Associated with Phenotype in Dementia with Lewy Bodies

It is currently unknown whether patients with dementia with Lewy bodies (DLB) with relatives with dementia or Parkinson’s disease (familial DLB patients) have a different phenotype than sporadic DLB patients. In this study, we aimed to examine disease onset, rate of cognitive decline, survival, and Alzheimer’s disease (AD) biomarkers in patients with familial DLB (n = 154) and sporadic DLB (n = 137), using linear mixed model analysis and Cox regression analysis, among others. Familial patients had a shorter survival (8.0 years) and more often elevated cerebrospinal fluid AD biomarkers (47%) than sporadic patients (9.0 years; p≤0.001; 30%, p = 0.037). Our findings suggest that genetic factors are important in DLB and that the identification of new genetic factors will probably improve the prediction of prognosis.

Genetic Architecture and Molecular, Imaging and Prodromic Markers in Dementia with Lewy Bodies: State of the Art, Opportunities and Challenges

Dementia with Lewy bodies (DLB) is one of the most common causes of dementia and belongs to the group of α-synucleinopathies. Due to its clinical overlap with other neurodegenerative disorders and its high clinical heterogeneity, the clinical differential diagnosis of DLB from other similar disorders is often difficult and it is frequently underdiagnosed. Moreover, its genetic etiology has been studied only recently due to the unavailability of large cohorts with a certain diagnosis and shows genetic heterogeneity with a rare contribution of pathogenic mutations and relatively common risk factors. The rapid increase in the reported cases of DLB highlights the need for an easy, efficient and accurate diagnosis of the disease in its initial stages in order to halt or delay the progression. The currently used diagnostic methods proposed by the International DLB consortium rely on a list of criteria that comprises both clinical observations and the use of biomarkers. Herein, we summarize the up-to-now reported knowledge on the genetic architecture of DLB and discuss the use of prodromal biomarkers as well as recent promising candidates from alternative body fluids and new imaging techniques.

Dementia with Lewy bodies in first-generation immigrants in a European memory clinic

We wanted to explore possible differences in disease presentation, frequency, and age of onset of dementia with Lewy bodies (DLB) between first-generation immigrants (FGI) and patients born in Belgium (PBIB). We conducted a retrospective study on all patients of our Memory Clinic between June 1, 2010 and January 31, 2020. A synucleinopathy was diagnosed in 150 of 2702 patients (5.5%): 91 received a diagnosis of DLB (3.4%). FGI were two times more likely to receive a diagnosis of DLB, due to a higher prevalence in North-Africans and Latin-Americans. Visual hallucinations were less frequent in North-Africans than in other immigrants. FGI were younger than PBIB and reported more often parasomnia. Our data suggest a higher risk for DLB in certain immigrant groups. Especially for North-African patients, a genetic factor can be suspected, namely mutations in Leucine-rich repeat kinase 2 (LRRK2). Memory clinics with a high rate of FGI may provide interesting data and insights into the prevalence of DLB, genetic and environmental differences.

Atypical parkinsonian syndromes in a North African tertiary referral center

INTRODUCTION

Data on epidemiology of atypical parkinsonian syndromes (APS) in North African countries are limited. Our objective was to study the epidemiological features of APS in a Tunisian population.

METHODS

We conducted a 17-year retrospective cross-sectional descriptive study in the Department of Neurology at Razi University Hospital. We included all patients responding to consensus diagnosis criteria of APS. We recorded demographic and clinical data. Group differences were assessed with a post hoc ANOVA with a Bonferroni error correction.

RESULTS

We included 464 APS patients. Hospital prevalence of APS among all parkinsonism cases was 20.6%. Mean annual increase of incidence defined as newly diagnosed APS cases per year reached 38.8%/year. APS were divided into 4 etiological subgroups: dementia with Lewy bodies (DLB; 56.7%); progressive supranuclear palsy(PSP; 16.2%); multiple system atrophy (MSA; 14.6%); and finally corticobasal syndrome (CBS; 12.5%). Sex-ratio was 1.2. This male predominance was found in all subgroups except MSA (p = .013). Mean age at onset was 68.5 years, most belated in DLB (69.7 years; p < .001). Young-onset parkinsonism (<40 years) was found only in MSA subgroup (p = .031). Parkinsonism was of late onset (>70 years) in 50.7% of patients and was significantly associated with DLB subgroup (p = .013). Inaugural parkinsonism was associated with CBS and MSA (p = .0497), and gait disorders at disease onset were associated with PSP and MSA (p = .0062). Cognitive and mood disorders were more marked in DLB and most preserved in MSA. Consanguinity was more marked in CBS (p = .037), and family history of dementia and psychiatric diseases was more common in DLB. Thirty-seven families with similar cases of APS were identified.

CONCLUSIONS

This is the largest African epidemiological study on APS. In our population, APS were frequent and dominated by DLB. The age of onset of parkinsonism was the most decisive feature for differential diagnosis.

What do we know about the risks of developing dementia after traumatic brain injury?

Traumatic brain injury (TBI) is a risk factor for the later development of dementia, but although the evidence dates back to the early 20^th century, the nature of any association and its mechanistic pathways remain unclear. There has been greater focus on this subject over recent years, in part because of increasing reports around sports related TBIs, especially in the USA. Differences in research methods and clinical sampling remain the primary reason for the variable findings, although there is clearly increased prevalence of neurodegenerative disorders in general. Duration of follow up, definition of both TBI and dementia, and differences in the extent to which other dementia risk factors are controlled, as well as concerns about medical record accuracy are all issues yet to be resolved in TBI research, as is an absence pathological evidence. In addition, TBI has been reported to initiate a cascade of pathological processes related to several neurodegenerative disorders, and as such, it is likely that the risks vary between individuals. Given the evidence that dementia risk may increase with injury severity and frequency, a detailed account of age and type of injury, as well as lifetime TBI exposure is essential to document in future studies, and further longitudinal research with biomarker assessments are needed.

Cardiovascular Disease, Diabetes Mellitus, and Hypertension in Lewy Body Disease: A Comparison with Other Dementia Disorders

Background:

Research concerning the potential roles of cardiovascular disease (CaVD) and diabetes mellitus (DM) as risk factors for Lewy body disease (LBD) is limited. These disorders are, however, established risk factors for vascular dementia (VaD) and have been proposed as risk factors for Alzheimer’s disease (AD).

Objective:

The aim of this study was to investigate the prevalence of CaVD and DM in LBD and compare the results with previous findings in cases with AD, VaD, and mixed AD-VaD (MD).

Methods:

Autopsy reports at the Clinical Department of Pathology in Lund from 2001–2018 were analyzed. All cases with a complete neuropathological diagnosis of LBD were selected, not distinguishing between subjects with clinical Parkinson disease dementia and dementia with Lewy bodies, on the condition of a clinical diagnosis of dementia. Clinical data were retrieved through the patients’ medical records and the Swedish National Diabetes Register (NDR) and compared with those of the AD, VaD, and MD cases.

Results:

In LBD, there was less CaVD, significantly less DM (p = 0.002) and likewise significantly less hypertension (p < 0.001) than in VaD. The results of the LBD group were consistent with the results of the AD group.

Conclusion:

Our findings of a low prevalence of CaVD and CaVD risk factors in LBD and in AD argue against the association between these risk factors and their contribution to the development of neurodegenerative diseases.

Trends in Glucocerebrosides Research: A Systematic Review

Glucocerebrosides are sphingolipid components of cell membranes that intervene in numerous cell biological processes and signaling pathways and that deregulation is implicated in human diseases such as Gaucher disease and Parkinson's disease. In the present study, we conducted a systematic review using document co-citation analysis, clustering and visualization tools to explore the trends and knowledge structure of glucocerebrosides research as indexed in the Science Citation Index Expanded database (1956-present). A co-citation network of 5,324 publications related to glucocerebrosides was constructed. The analysis of emerging categories and keywords suggested a growth of research related to neurosciences over the last decade. We identified ten major areas of research (e.g., clusters) that developed over time, from the oldest (i.e., on glucocerebrosidase protein or molecular analysis of the GBA gene) to the most recent ones (i.e., on drug resistance in cancer, pharmacological chaperones, or Parkinson's disease). We provided for each cluster the most cited publications and a description of their intellectual content. We moreover identified emerging trends in glucocerebrosides research by detecting the surges in the rate of publication citations in the most recent years. In conclusion, this study helps to apprehend the most significant lines of research on glucocerebrosides. This should strengthen the connections between scientific communities studying glycosphingolipids to facilitate advances, especially for the most recent researches on cancer drug resistance and Parkinson's disease.

Traumatic Brain Injury and Risk of Long-Term Brain Changes, Accumulation of Pathological Markers, and Developing Dementia: A Review

Traumatic brain injuries (TBI) have received widespread media attention in recent years as being a risk factor for the development of dementia and chronic traumatic encephalopathy (CTE). This has sparked fears about the potential long-term effects of TBI of any severity on cognitive aging, leading to a public health concern. This article reviews the evidence surrounding TBI as a risk factor for the later development of changes in brain structure and function, and an increased risk of neurodegenerative disorders. A number of studies have shown evidence of long-term brain changes and accumulation of pathological biomarkers (e.g., amyloid and tau proteins) related to a history of moderate-to-severe TBI, and research has also demonstrated that individuals with moderate-to-severe injuries have an increased risk of dementia. While milder injuries have been found to be associated with an increased risk for dementia in some recent studies, reports on long-term brain changes have been mixed and often are complicated by factors related to injury exposure (i.e., number of injuries) and severity/complications, psychiatric conditions, and opioid use disorder. CTE, although often described as a neurodegenerative disorder, remains a neuropathological condition that is poorly understood. Future research is needed to clarify the significance of CTE pathology and determine whether that can explain any clinical symptoms. Overall, it is clear that most individuals who sustain a TBI (particularly milder injuries) do not experience worse outcomes with aging, as the incidence for dementia is found to be less than 7% across the literature.

Genetic architecture of common non-Alzheimer's disease dementias

Frontotemporal dementia (FTD), dementia with Lewy bodies (DLB) and vascular dementia (VaD) are the most common forms of dementia after Alzheimer's disease (AD). The heterogeneity of these disorders and/or the clinical overlap with other diseases hinder the study of their genetic components. Even though Mendelian dementias are rare, the study of these forms of disease can have a significant impact in the lives of patients and families and have successfully brought to the fore many of the genes currently known to be involved in FTD and VaD, starting to give us a glimpse of the molecular mechanisms underlying these phenotypes. More recently, genome-wide association studies have also pointed to disease risk-associated loci. This has been particularly important for DLB where familial forms of disease are very rarely described. In this review we systematically describe the Mendelian and risk genes involved in these non-AD dementias in an effort to contribute to a better understanding of their genetic architecture, find differences and commonalities between different dementia phenotypes, and uncover areas that would benefit from more intense research endeavors.

A Neurologist's Guide to REM Sleep Behavior Disorder

REM Sleep Behavior Disorder (RBD) is a chronic sleep condition characterized by dream enactment and loss of REM atonia. Individuals often present to clinic with complaints of injury to themselves or their bed-partner due to violent movements during sleep. RBD patients have a high risk of developing one of the neurodegenerative α-synucleinopathy diseases: over 70% will develop parkinsonism or dementia within 12 years of their diagnosis. RBD patients also exhibit accelerated disease progression and a more severe phenotype than α-synucleinopathy sufferers without RBD. The disease's low prevalence and the relatively limited awareness of the condition amongst medical professionals makes the diagnosis and treatment of RBD challenging. Uncertainty in patient management is further exacerbated by a lack of clinical guidelines for RBD patient care. There are no binary prognostic markers for RBD disease course and there are no clinical guidelines for neurodegeneration scaling or tracking in these patients. Both clinicians and patients are therefore forced to deal with uncertain outcomes. In this review, we summarize RBD pathology and differential diagnoses, diagnostic, and treatment guidelines as well as prognostic recommendations with a look to current research in the scientific field. We aim to raise awareness and develop a framework for best practice for RBD patient management.