Alzheimer's Disease Co-pathology Research Articles

Clinical and neuropathological associations of plasma Aβ42/Aβ40, p-tau217 and neurofilament light in sporadic frontotemporal dementia spectrum disorders.

Plasma amyloid beta42/amyloid beta40 (Aβ42/Aβ40) and phosphorylated tau217 (p-tau217) identify individuals with primary Alzheimer's disease (AD). They may detect AD co-pathology in the setting of other primary neurodegenerative diseases, but this has not been systematically studied. We compared the clinical, neuroimaging, and neuropathological associations of plasma Aβ42/Aβ40 (mass spectrometry), p-tau217 (electrochemiluminescence), and neurofilament light ([NfL], single molecule array [Simoa]), as markers of AD co-pathology, in a sporadic frontotemporal dementia (FTD) cohort (n=620). Aβ42/Aβ40 showed no clinicopathological associations. High p-tau217 was present in amnestic dementia (AmD) presumed to be due to FTD, logopenic primary progressive aphasia (lvPPA), and APOEε4 carriers, and correlated with worse baseline and longitudinal clinical scores, lower hippocampal volumes, and more severe AD co-pathology (Braak Stage). NfL was elevated in all FTD phenotypes, and correlated with clinical scores and frontotemporal brain volumes. Plasma p-tau217 has clinical, neuroimaging, and neuropathological correlates in sporadic FTD and may identify FTD cases with AD co-pathology. Alzheimer's disease (AD) features could be identified with plasma phosphorylated tau217 (p-tau217) in frontotemporal lobar degeneration (FTLD).Plasma p-tau217 is a better discriminator of AD co-pathology and AD-associated features in FTLD than plasma amyloid beta42/amyloid beta40 (Aβ42/Aβ40) and neurofilament light (NfL).In FTLD, plasma p-tau217, but not Aβ42/Aβ40 or neurofilament light, has phenotypical, neurocognitive, and neuroimaging correlates suggestive of AD co-pathology.

The association of seizure control with neuropathology in dementia.

Seizures in people with dementia (PWD) are associated with faster cognitive decline and worse clinical outcomes. However, the relationship between ongoing seizure activity and postmortem neuropathology in PWD remains unexplored. We compared post-mortem findings in PWD with active, remote, and no seizures using multicentre data from 39 Alzheimer's Disease Centres from 2005 to 2021. PWD were grouped by seizure status into active (seizures over the preceding one year), remote (prior seizures but none in the preceding year), and no seizures (controls). Baseline demographics, cognition, mortality, and postmortem findings of primary and contributing(co-pathologies) Alzheimer's Disease(AD), Frontotemporal lobar degeneration(FTD), Lewy body, vascular pathologies and neurodegeneration were compared among the groups using Pearson's Chi-squared test, fisher's exact test, t-test, and ANOVA tests. Of 10,474 deceased PWD, active seizure participants suffered the highest mortality among the groups(proportion deceased among the groups: active=56%remote=35%, controls=34%, p<0.001). Among 6085 (58.1% of deceased) who underwent autopsy, 294 had active, 151 had remote, and 5640 had no seizures. PWD and active seizures died at a younger age (Active=75.8, remote=77.9, controls: 80.8 years, p <0.001) and had more severe dementia (CDR-Global: active=2.36, remote=1.90, controls=1.69, p<0.001). In post hoc analyses, those with primary postmortem diagnosis of AD with active seizures had more severe and later stages of AD pathology and ATN (amyloid, tau, and neurodegeneration) as evidenced by Braak stage for neurofibrillary(tau) degeneration and CERAD score density of neuritic(amyloid) plaques than remote seizure participants and controls. Active seizure participants had more neurodegeneration, evidenced by cerebral atrophy, hippocampal atrophy, and locus coeruleus hypopigmentation than controls. Among participants with primary postmortem diagnosis of non-AD, in posthoc analyses, active seizure participants had worse AD co-pathology evidenced by higher Braak stages than remote seizures and controls and a higher thal phase of beta-amyloid plaques than controls. Neurodegeneration (cerebral/hippocampal atrophy) and LC hypopigmentation were comparable among the groups. In both primary postmortem AD and non-AD diagnoses, FTD (co)pathology was less prevalent among active seizure participants than controls, while vascular pathology, Circle of Willis atherosclerosis, Lewy body pathology, lobar atrophy, and substantia nigra hypopigmentation were comparable among the three groups. This study shows that active, compared to remote seizures, are associated with earlier death and postmortem evidence of more severe ATN pathology. Active seizures are associated with more advanced AD pathology in AD and worse AD co-pathology in non-AD dementias. Therefore, clinicians should be vigilant in detecting ongoing seizures as this could reflect a worse prognosis in PWD.

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

Lewy body disorders (LBD), encompassing Parkinson disease (PD), PD dementia (PDD), and dementia with Lewy bodies (DLB), are characterized by alpha-synuclein pathology but often are accompanied by Alzheimer's disease (AD) neuropathological change (ADNC). The medial temporal lobe (MTL) is a primary locus of tau accumulation and associated neurodegeneration in AD. However, it is unclear the extent to which AD copathology in LBD (LBD/AD+) contributes to MTL-specific patterns of degeneration. We employ a MTL subregional segmentation strategy of T1-weighted (T1w) MRI in biomarker-supported or autopsy-confirmed LBD and LBD/AD+to investigate the anatomic consequences of co-occurring LBD/AD+pathology on neurodegeneration. We studied 167 individuals with clinical diagnoses of LBD (PD, n=124 (74.3%); PDD, n=11 (6.6%); DLB, n=32 (19.2%)) with available T1w MRI and AD biomarkers or autopsy evidence of ADNC. Individuals were further biologically classified as LBD/AD+based on hierarchical evidence of ADNC pathology: 1) AD "intermediate" or "high" by ABC neuropathologic criteria (n=39 (23.4%)); 2) positive amyloid PET (n=2 (1.2%)); or 3) CSF β-amyloid1-42<185.7pg/mL n=126 (75.4%)). The T1 Automated Segmentation of Hippocampal Subfields (ASHS) pipeline was used to compute volume and thickness measurements of MTL subregions in LBD/AD- and LBD/AD+. Linear regression tested the association of AD copathology and subregion volume/thickness, covarying for age and sex, and intracranial volume for volume measurements. Secondary analyses correlated MTL subregional volume/thickness with cognition and neuropathology. LBD/AD+had decreased volume/thickness compared to LBD/AD- in all MTL subregions except posterior hippocampus. The greatest effect sizes were seen in Brodmann Area 35 (BA35) (Cohen's d=0.62, p=0.002, β=0.107±0.034), and entorhinal cortex (ERC) (Cohen's d=0.56, p=0.006, β=0.088±0.031). Smaller differences were seen in the parahippocampal cortex (PHC) (Cohen's d=0.5, p=0.012, β=0.082±0.033), BA36 (Cohen's d=0.47, p=0.021, β=0.090±0.039) and anterior hippocampus (Cohen's d=0.45, p=0.029, β=111.790±50.595). Verbal memory scores positively correlated with volume/thickness in anterior and posterior hippocampus, BA35, ERC and PHC, while visuospatial memory positively correlated only in BA35. In the subset of participants with autopsy, lower ERC volume was associated with a higher tau load in ERC (adjusted odds ratio 0.013, 95% CI [0.0002, 0.841], uncorrected p=0.041). Relative to LBD/AD-, LBD/AD+has greater T1w MRI evidence of atrophy in multiple MTL subregions. Atrophy in MTL subregions associates with memory performance and tau pathological load. The observed pattern of atrophy largely follows expectation from AD Braak stages, except for posterior hippocampus. Longitudinal studies are needed to validate the hypothesized spread of neurodegeneration.

Plasma phosphorylated tau and neuropsychiatric symptoms in dementia with Lewy bodies.

Neuropsychiatric symptoms (NPSs) are common in dementia with Lewy bodies (DLB) but their neurobiological mechanisms are poorly understood. NPSs and cognition were assessed annually in participants (DLB n=222; Alzheimer's disease [AD] n=125) from the European DLB (E-DLB) Consortium, and plasma phosphorylated tau-181 (p-tau181) and p-tau231 concentrations were measured at baseline. Hallucinations, delusions, and depression were more common in DLB than in AD and, in a subgroup with longitudinal follow-up, persistent hallucinations and NPSs were associated with lower p-tau181 and p-tau231 in DLB. In adjusted linear mixed-effects models, hallucinations at baseline were associated with greater longitudinal cognitive impairment in DLB, with a significant interaction with p-tau231. Higher p-tau181 and p-tau231 levels were associated with a lower longitudinal risk of NPSs and hallucinations in early-stage DLB. However, the interaction between hallucinations and p-tau231 suggests that when AD co-pathology and hallucinations do co-exist in DLB that they may synergistically exacerbate cognitive decline. Neuropsychiatric symptoms (NPSs) were more common in dementia with Lewy bodies (DLB) than in Alzheimer's disease (AD). Lower plasma phosphorylated tau-231 (p-tau231) and p-tau181 levels were associated with persistent hallucinations in DLB. Lower plasma p-tau231 and p-tau181 levels were associated with an increased risk of persistent NPSs in early DLB. Hallucinations at baseline were associated with greater cognitive dysfunction in DLB, and there was an interaction with p-tau231.

Iatrogenic cerebral amyloid angiopathy and Alzheimer's disease co-pathology.

Iatrogenic cerebral amyloid angiopathy, a disease caused by contact with neurosurgical material or human growth hormone contaminated by beta-amyloid peptide (Aβ), has a prion-like transmission mechanism. We present a series of three patients under 55 years of age who underwent cranial surgery. All of them developed multiple cerebral hemorrhages, transient focal neurological deficits, and/or cognitive impairment after 3-4 decades. MRI was compatible with CAA, and Aβ deposition was confirmed. The third patient, who had a ventriculoperitoneal valve, also showed Aβ deposition in the peritoneum and diagnostic biomarkers of Alzheimer's disease. Co-pathology with Alzheimer disease and its iatrogenic transmission should be considered.

In Vivo Prevalence of Beta-Amyloid Pathology and Alzheimer's Disease Co-Pathology in Idiopathic Normal-Pressure Hydrocephalus-Association with Neuropsychological Features.

Idiopathic normal-pressure hydrocephalus (iNPH) is a clinic-radiological neurological syndrome presenting with cognitive deficits, gait disturbances and urinary incontinence. It often coexists with Alzheimer's disease (AD). Due to the reversible nature of iNPH when promptly treated, a lot of studies have focused on possible biomarkers, among which are cerebrospinal fluid (CSF) biomarkers. The aim of the present study was to determine the rate of beta-amyloid pathology and AD co-pathology by measuring AD CSF biomarkers, namely, amyloid beta with 42 and 40 amino acids (Aβ42), the Aβ42/Aβ40 ratio, total Tau protein (t-Tau) and phosphorylated Tau protein at threonine 181 (p-Tau), in a cohort of iNPH patients, as well as to investigate the possible associations among CSF biomarkers and iNPH neuropsychological profiles. Fifty-three patients with iNPH were included in the present study. CSF Aβ42, Aβ40, t-Tau and p-Tau were measured in duplicate with double-sandwich ELISA assays. The neuropsychological evaluation consisted of the Mini-Mental State Examination, Frontal Assessment Battery, Five-Word Test and CLOX drawing tests 1 and 2. After statistical analysis, we found that amyloid pathology and AD co-pathology are rather common in iNPH patients and that higher values of t-Tau and p-Tau CSF levels, as well as the existence of the AD CSF profile, are associated with more severe memory impairment in the study patients. In conclusion, our study has confirmed that amyloid pathology and AD-co-pathology are rather common in iNPH patients and that CSF markers of AD pathology and t-Tau are associated with a worse memory decline in these patients.

Clinical and diagnostic implications of Alzheimer's disease copathology in Lewy body disease.

Concomitant Alzheimer's disease (AD) pathology is a frequent event in the context of Lewy body disease (LBD), occurring in approximately half of all cases. Evidence shows that LBD patients with AD copathology show an accelerated disease course, a greater risk of cognitive decline and an overall poorer prognosis. However, LBD-AD cases may show heterogeneous motor and non-motor phenotypes with a higher risk of dementia and, consequently, be not rarely misdiagnosed. In this review, we summarize the current understanding of LBD-AD by discussing the synergistic effects of AD neuropathological changes and Lewy pathology and their clinical relevance. Furthermore, we provide an extensive overview of neuroimaging and fluid biomarkers under assessment for use in LBD-AD and their possible diagnostic and prognostic values. AD pathology can be predicted in vivo by means of CSF, MRI and PET markers, whereas the most promising technique to date for identifying Lewy pathology in different biological tissues is the α-synuclein seed amplification assay. Pathological imaging and CSF AD biomarkers are associated with a higher likelihood of cognitive decline in LBD but do not always mirror the neuropathological severity as in pure AD. Implementing the use of blood-based AD biomarkers might allow faster screening of LBD patients for AD copathology, thus improving the overall diagnostic sensitivity for LBD-AD. Finally, we discuss the literature on novel candidate biomarkers being exploited in LBD-AD to investigate other aspects of neurodegeneration, such as neuroaxonal injury, glial activation and synaptic dysfunction. The thorough characterization of AD copathology in LBD should be taken into account when considering differential diagnoses of dementia syndromes, to allow prognostic evaluation on an individual level, and to guide symptomatic and disease-modifying therapies.

Performance of plasma p-tau217 and NfL in an unselected memory clinic setting.

Plasma phosphorylated tau-217 (p-tau217) and neurofilament light (NfL) can differentiate between different dementias in selected cohorts. We aim to test the discrimination potential of these markers in a real-world cohort. We measured p-tau217 (ALZpath) and NfL (Quanterix) in 415 (unselected) consecutive memory clinic patients. Biomarker levels were dichotomized as low/high to create four biomarker profiles based on p-tau217 and NfL levels. p-Tau217 levels were highest in patients with Alzheimer's disease (AD) dementia, whereas NfL levels were highest in patients with frontotemporal dementia (FTD). Low p-tau217/low NfL was associated mostly with non-neurological diagnoses (79%), and high p-tau217/low NfL indicated AD pathology at any stage (84%). Low p-tau217/high NfL indicated FTD (38%) and high p-tau217/high NfL indicated AD dementia (87%). p-Tau217 can identify AD pathology at any disease stage. NfL can differentiate FTD from other diagnoses (e.g., AD dementia). Plasma p-tau217 and NfL can support clinical decision-making, and we suggest using them as complements to standard clinical assessment. Phosphorylated tau-2017 (p-tau217) can detect Alzheimer's disease (AD) across the clinical continuum.Neurofilament light (NfL) can differentiate frontotemporal dementia (FTD) from other diagnoses (AD dementia, dementia with Lewy bodies [DLB], and Psychiatry).p-Tau217 may detect AD co-pathology in other diseases or dementia types (e.g., DLB).p-Tau217 and NfL show potential for clinical implementation.

The Underestimated Relevance of Alzheimer's Disease Copathology in Amyotrophic Lateral Sclerosis.

Concomitant Alzheimer's disease (AD) pathology can be observed in approximately 10-15% of cases with amyotrophic lateral sclerosis (ALS). ALS-AD patients have a higher prevalence of amnestic cognitive disturbances, which may often precede motor symptoms. Cerebrospinal fluid (CSF) AD core biomarkers usually show no or slightly significant changes in ALS, whereas blood phosphorylated tau protein might be increased independently from AD copathology. Neurofilament proteins are consistently elevated in CSF and blood of ALS, but have been poorly investigated in ALS-AD. All these issues should be taken into account when using fluid biomarkers as inclusion criteria or secondary endpoints in clinical trials.

Amyloid-Beta Co-Pathology Is a Major Determinant of the Elevated Plasma GFAP Values in Amyotrophic Lateral Sclerosis.

Recent studies reported increased plasma glial acidic fibrillary protein (GFAP) levels in amyotrophic lateral sclerosis (ALS) patients compared to controls. We expanded these findings in a larger cohort, including 156 ALS patients and 48 controls, and investigated the associations of plasma GFAP with clinical variables and other biofluid biomarkers. Plasma GFAP and Alzheimer's disease (AD) cerebrospinal fluid (CSF) biomarkers were assessed by the single molecule array and the Lumipulse platforms, respectively. In ALS patients, plasma GFAP was higher than in controls (p < 0.001) and associated with measures of cognitive decline. Twenty ALS patients (12.8%) showed a positive amyloid status (A+), of which nine also exhibited tau pathology (A+T+, namely ALS-AD). ALS-AD patients showed higher plasma GFAP than A- ALS participants (p < 0.001) and controls (p < 0.001), whereas the comparison between A- ALS and controls missed statistical significance (p = 0.07). Plasma GFAP distinguished ALS-AD subjects more accurately (area under the curve (AUC) 0.932 ± 0.027) than plasma p-tau181 (AUC 0.692 ± 0.058, p < 0.0001) and plasma neurofilament light chain protein (AUC, 0.548 ± 0.088, p < 0.0001). Cognitive measures differed between ALS-AD and other ALS patients. AD co-pathology deeply affects plasma GFAP values in ALS patients. Plasma GFAP is an accurate biomarker for identifying AD co-pathology in ALS, which can influence the cognitive phenotype.

Association of Plasma Phosphorylated Tau With the Response to Neflamapimod Treatment in Patients With Dementia With Lewy Bodies.

In a proportion of patients, dementia with Lewy bodies (DLB) is associated with Alzheimer disease (AD) copathology, which is linked to accelerated cognitive decline and more extensive cortical atrophy. The objective was to evaluate the relationship between a biomarker of AD copathology, plasma tau phosphorylated at residue 181 (ptau181), and the treatment effects of the p38α kinase inhibitor neflamapimod, which targets the cholinergic degenerative process in DLB. The AscenD-LB study was a phase 2a, randomized (1:1), 16-week, placebo-controlled clinical trial of neflamapimod in DLB, the main results of which have been published. After the study was completed (i.e., post hoc), pretreatment plasma ptau181 levels were determined and participants were grouped based on a cutoff for AD pathology of 2.2 pg/mL (established in a separate cohort to identify AD from healthy controls). Clinical outcomes for the comparison of placebo with neflamapimod 40 mg three times daily (TID; the higher and more clinically active of 2 doses studied) were analyzed using mixed models for repeated measures within each subgroup (baseline plasma ptau181 < and ≥2.2 pg/mL). Pretreatment plasma ptau181 levels were determined in eighty-five participants with mild-to-moderate DLB receiving cholinesterase inhibitors, with 45 participants below and 40 above the 2.2 pg/mL cutoff at baseline. In the 16-week treatment period, in the comparison of placebo with neflamapimod 40 mg TID, for all end points evaluated, improvements with neflamapimod treatment were greater in participants below the cutoff, compared with those above the cutoff. In addition, participants below the ptau181 cutoff at baseline showed significant improvement over placebo in an attention composite measure (+0.42, 95% CI 0.07-0.78, p = 0.023, d = 0.78), the Clinical Dementia Rating Scale Sum of Boxes (-0.60, 95% CI -1.04 to -0.06, p = 0.031, d = 0.70), the Timed Up and Go test (-3.1 seconds, 95% CI -4.7 to -1.6, p < 0.001, d = 0.74), and International Shopping List Test-Recognition (+1.4, 95% CI 0.2-2.5, p = 0.024, d = 1.00). Exclusion of patients with elevated plasma ptau181, potentially through excluding patients with extensive cortical neurodegeneration, enriches for a patient with DLB population that is more responsive to neflamapimod. More generally, plasma biomarkers of AD copathology at study entry should be considered as stratification variables in DLB clinical trials. NCT04001517 at ClinicalTrials.gov.

Lysosomal polygenic risk is associated with the severity of neuropathology in Lewy body disease.

Intraneuronal accumulation of misfolded α-synuclein is the pathological hallmark of Parkinson's disease and dementia with Lewy bodies, often co-occurring with variable degrees of Alzheimer's disease related neuropathology. Genetic association studies have successfully identified common variants associated with disease risk and phenotypic traits in Lewy body disease, yet little is known about the genetic contribution to neuropathological heterogeneity. Using summary statistics from Parkinson's disease and Alzheimer's disease genome-wide association studies, we calculated polygenic risk scores and investigated the relationship with Lewy, amyloid-β and tau pathology. Associations were nominated in neuropathologically defined samples with Lewy body disease from the Netherlands Brain Bank (n = 217) and followed up in an independent sample series from the Mayo Clinic Brain Bank (n = 394). We also generated stratified polygenic risk scores based on single-nucleotide polymorphisms annotated to eight functional pathways or cell types previously implicated in Parkinson's disease and assessed for association with Lewy pathology in subgroups with and without significant Alzheimer's disease co-pathology. In an ordinal logistic regression model, the Alzheimer's disease polygenic risk score was associated with concomitant amyloid-β and tau pathology in both cohorts. Moreover, both cohorts showed a significant association between lysosomal pathway polygenic risk and Lewy pathology, which was more consistent than the association with a general Parkinson's disease risk score and specific to the subset of samples without significant concomitant Alzheimer's disease related neuropathology. Our findings provide proof of principle that the specific risk alleles a patient carries for Parkinson's and Alzheimer's disease also influence key aspects of the underlying neuropathology in Lewy body disease. The interrelations between genetic architecture and neuropathology are complex, as our results implicate lysosomal risk loci specifically in the subset of samples without Alzheimer's disease co-pathology. Our findings hold promise that genetic profiling may help predict the vulnerability to specific neuropathologies in Lewy body disease, with potential relevance for the further development of precision medicine in these disorders.

CSF Synaptic Biomarkers in AT(N)-Based Subgroups of Lewy Body Disease.

Patients with Lewy body disease (LBD) often show a co-occurring Alzheimer disease (AD) pathology. CSF biomarkers allow the detection in vivo of AD-related pathologic hallmarks included in the amyloid-tau-neurodegeneration (AT(N)) classification system. Here, we aimed to investigate whether CSF biomarkers of synaptic and neuroaxonal damage are correlated with the presence of AD copathology in LBD and can be useful to differentiate patients with LBD with different AT(N) profiles. We retrospectively measured CSF levels of AD core biomarkers (Aβ42/40 ratio, phosphorylated tau protein, and total tau protein) and of synaptic (β-synuclein, α-synuclein, synaptosomal-associated protein 25 [SNAP-25], and neurogranin) and neuroaxonal proteins (neurofilament light chain [NfL]) in 28 cognitively unimpaired participants with nondegenerative neurologic conditions and 161 participants with a diagnosis of either LBD or AD (at both mild cognitive impairment, AD-MCI, and dementia stages, AD-dem). We compared CSF biomarker levels in clinical and AT(N)-based subgroups. CSF β-synuclein, α-synuclein, SNAP-25, neurogranin, and NfL levels did not differ between LBD (n = 101, age 67.2 ± 7.8 years, 27.7% females) and controls (age 64.8 ± 8.6 years, 39.3% females) and were increased in AD (AD-MCI: n = 30, AD-dem: n = 30, age 72.3 ± 6.0 years, 63.3% females) compared with both groups (p < 0.001 for all comparisons). In LBD, we found increased levels of synaptic and neuroaxonal degeneration biomarkers in patients with A+T+ (LBD/A+T+) than with A-T- profiles (LBD/A-T-) (p < 0.01 for all), and β-synuclein showed the highest discriminative accuracy between the 2 groups (area under the curve 0.938, 95% CI 0.884-0.991). CSF β-synuclein (p = 0.0021), α-synuclein (p = 0.0099), and SNAP-25 concentrations (p = 0.013) were also higher in LBD/A+T+ than in LBD/A+T- cases, which had synaptic biomarker levels within the normal range. CSF α-synuclein was significantly decreased only in patients with LBD with T- profiles compared with controls (p = 0.0448). Moreover, LBD/A+T+ and AD cases did not differ in any biomarker level. LBD/A+T+ and AD cases showed significantly increased CSF levels of synaptic and neuroaxonal biomarkers compared with LBD/A-T- and control subjects. Patients with LBD and AT(N)-based AD copathology showed, thus, a distinct signature of synaptic dysfunction from other LBD cases. This study provides Class II evidence that CSF levels of β-synuclein, α-synuclein, SNAP-25, neurogranin, and NfL are higher in patients with AD than in patients with LBD.

Natural speech markers of Alzheimer's disease co-pathology in Lewy body dementias

IntroductionAn estimated 50% of patients with Lewy body dementias (LBD), including Parkinson's disease dementia (PDD) and Dementia with Lewy bodies (DLB), have co-occurring Alzheimer's disease (AD) that is associated with worse prognosis. This study tests an automated analysis of natural speech as an inexpensive, non-invasive screening tool for AD co-pathology in biologically-confirmed cohorts of LBD patients with AD co-pathology (SYN + AD) and without (SYN-AD). MethodsWe analyzed lexical-semantic and acoustic features of picture descriptions using automated methods in 22 SYN + AD and 38 SYN-AD patients stratified using AD CSF biomarkers or autopsy diagnosis. Speech markers of AD co-pathology were identified using best subset regression, and their diagnostic discrimination was tested using receiver operating characteristic. ANCOVAs compared measures between groups covarying for demographic differences and cognitive disease severity. We tested relations with CSF tau levels, and compared speech measures between PDD and DLB clinical disorders in the same cohort. ResultsAge of acquisition of nouns (p = 0.034, |d| = 0.77) and lexical density (p = 0.0064, |d| = 0.72) were reduced in SYN + AD, and together showed excellent discrimination for SYN + AD vs. SYN-AD (95% sensitivity, 66% specificity; AUC = 0.82). Lower lexical density was related to higher CSF t-Tau levels (R = −0.41, p = 0.0021). Clinically-diagnosed PDD vs. DLB did not differ on any speech features. ConclusionAD co-pathology may result in a deviant natural speech profile in LBD characterized by specific lexical-semantic impairments, not detectable by clinical disorder diagnosis. Our study demonstrates the potential of automated digital speech analytics as a screening tool for underlying AD co-pathology in LBD.

Non-tremor motor dysfunction in Lewy body dementias is associated with AD biomarkers

Motor features of Parkinson's disease (PD) are heterogeneous and well-studied; non-tremor features of postural instability and gait dysfunction (PIGD) have been linked to worse outcomes and Alzheimer's disease (AD) co-pathology. However, these features are understudied in Lewy body dementias (LBD). Here we perform retrospective analysis of a unique cohort of LBD (n = 30) with Unified Parkinson's Disease Rating Scale (UPDRS) data collected at baseline in proximity to cerebrospinal fluid collection to test the hypothesis that LBD patients with a positive AD biomarker profile (LBD + AD = 13) would have higher PIGD burden compared with LBD patients without AD biomarker positivity (LBD-AD = 17). We find novel evidence for selective impairment of PIGD burden in LBD + AD vs LBD-AD (OR = 1.95, 95%CI = 1.02–3.70, p = 0.04) and a direct association of increasing CSF tau/Aβ1-42 ratio with increasing PIGD disability in the total cohort (β = 0.23, SE = 0.08, p = 0.01). This unique biomarker stratification approach suggests AD co-pathology may contribute to PIGD motor signs in LBD.

Clinical Manifestations of Early-Onset Dementia With Lewy Bodies Compared With Late-Onset Dementia With Lewy Bodies and Early-Onset Alzheimer Disease

Early-onset dementia, presenting in individuals younger than 65 years, is a diagnosis with significant social and financial implications. The early-onset form of dementia with Lewy bodies (DLB) is poorly understood. To investigate clinical features that distinguish early-onset DLB (onset and diagnosis at age <65 years) from late-onset DLB (onset at age ≥65 years) and from early-onset Alzheimer disease (AD) dementia. This is a retrospective case-control study on patients with pathologically confirmed DLB or AD enrolled in the National Alzheimer's Coordinating Center database from January 2005 to July 2017. The National Alzheimer's Coordinating Center Uniform Data Set comprised deidentified data collected by Alzheimer disease centers in the United States. Of patients fulfilling criteria for all-cause dementia at enrollment (n = 1152), those who at post mortem received a pathological diagnosis of either AD (n = 848) or Lewy body disease (n = 218) were selected. Excluding 52 patients owing to missing data and 12 diagnosed with Parkinson disease dementia, remaining patients were classified by age of symptom onset into early-onset AD, early-onset DLB, and late-onset DLB subgroups. Data were analyzed from June to December 2018 and from November to December 2021. Demographics, cognitive, behavioral, and motor features recorded at first clinic visit and neuropathological characteristics at autopsy were analyzed by disease subgroup. Concordance between initial etiologic diagnosis of dementia and final pathological diagnosis was assessed, as was time to death. A total of 542 individuals were categorized as having early-onset AD (n = 363; mean [SD] age, 53.0 [5.8] years; 208 [57.3%] male), early-onset DLB (n = 32; mean [SD] age, 57.9 [3.2] years; 23 [71.9%] male), and late-onset DLB (n = 147; mean [SD] age, 73.5 [5.5] years; 103 [70.1%] male). Early-onset DLB was clinically misdiagnosed in 16 individuals (50%). Features that predicted a diagnosis of early-onset DLB over early-onset AD included visual hallucinations (15 [46.9%] vs 42 [11.6%]), slowness (23 [71.9%] vs 95 [26.2%]), apathy (23 [71.9%] vs 189 [52.1%]), and motor deterioration that preceded cognitive and behavioral symptoms (7 [21.9%] vs 6 [1.7%]). Late-onset DLB had more amnestic features, but this was accounted for by a higher proportion of neocortical neuritic plaques and diffuse plaques (frequent in 79 [53.7%] vs 8 [25%]) than seen in early-onset DLB. This study found that early-onset DLB has clinical features that distinguish it from early-onset AD, whereas features of late-onset DLB are associated with a higher burden of AD copathology.

Sex Differences for Clinical Correlates of Alzheimer's Pathology in People with Lewy Body Pathology.

Lewy body (LB) dementias have limited clinical diagnostic accuracy because of frequent copathologies contributing to clinical heterogeneity. Although sex differences in clinical prevalence and frequency of pure LB pathology were shown, differences for clinicopathological correlations are less known. The aim of this study was to determine sex differences for clinical associations of Alzheimer's disease (AD) copathology in those with LB pathology. Data were from National Alzheimer's Coordinating Center for 223 women and 468 men with limbic or neocortical LB, separated into two groups as those with high likelihood and low/intermediate likelihood for LB clinical phenotype based on pathology. Clinical associations of sex and interaction of sex and pathology for the clinical phenotype were analyzed. More severe AD copathology was associated with worse cognitive decline and lower likelihood of LB disease clinical phenotype. Women with more severe AD copathology and tau had worse cognitive decline and higher likelihood of AD clinical phenotype than men. Men with more severe AD copathology had lower likelihood of LB clinical phenotype than women. Interaction of sex and pathology was more pronounced in those aged between 70 and 80 years. AD copathology reduces the likelihood of LB clinical phenotype for both women and men; however, men may be at higher risk for LB disease underdiagnosis and women at higher risk for dementia. The use of both LB and AD biomarkers, even when LB or AD pathology is not clinically expected, is necessary for the accurate clinical diagnosis of both LB diseases and AD. © 2022 International Parkinson and Movement Disorder Society.

Genetic evaluation of dementia with Lewy bodies implicates distinct disease subgroups.

The APOE locus is strongly associated with risk for developing Alzheimer's disease and dementia with Lewy bodies. In particular, the role of the APOE ε4 allele as a putative driver of α-synuclein pathology is a topic of intense debate. Here, we performed a comprehensive evaluation in 2466 dementia with Lewy bodies cases versus 2928 neurologically healthy, aged controls. Using an APOE-stratified genome-wide association study approach, we found that GBA is associated with risk for dementia with Lewy bodies in patients without APOE ε4 (P = 6.58 × 10-9, OR = 3.41, 95% CI = 2.25-5.17), but not with dementia with Lewy bodies with APOE ε4 (P = 0.034, OR = 1.87, 95%, 95% CI = 1.05-3.37). We then divided 495 neuropathologically examined dementia with Lewy bodies cases into three groups based on the extent of concomitant Alzheimer's disease co-pathology: pure dementia with Lewy bodies (n = 88), dementia with Lewy bodies with intermediate Alzheimer's disease co-pathology (n = 66) and dementia with Lewy bodies with high Alzheimer's disease co-pathology (n = 341). In each group, we tested the association of the APOE ε4 against the 2928 neurologically healthy controls. Our examination found that APOE ε4 was associated with dementia with Lewy bodies + Alzheimer's disease (P = 1.29 × 10-32, OR = 4.25, 95% CI = 3.35-5.39) and dementia with Lewy bodies + intermediate Alzheimer's disease (P = 0.0011, OR = 2.31, 95% CI = 1.40-3.83), but not with pure dementia with Lewy bodies (P = 0.31, OR = 0.75, 95% CI = 0.43-1.30). In conclusion, although deep clinical data were not available for these samples, our findings do not support the notion that APOE ε4 is an independent driver of α-synuclein pathology in pure dementia with Lewy bodies, but rather implicate GBA as the main risk gene for the pure dementia with Lewy bodies subgroup.

Different patterns of hippocampal subfield pathology in Lewy body disease and Alzheimer's disease

Coughlin and colleagues [1] recently examined the association between hippocampal α-synuclein (SYN) and tau pathologies in 49 autopsy-confirmed cases of Lewy body diseases (LBD) - 30 with no/low Alzheimer disease (AD) co-pathology (LBD - AD) and 19 with moderate/high AD co-pathology (LBD + AD) aged at death 77.3 and 78.6 years, and disease duration 15.8 and 9.1 years, respectively, and 30 AD patients with a mean age of 74.4 years. 67% and 89%, respectively, were neocortical, 27% and 11%, respectively, limbic LBD stage, with only very few brainstem predominant forms [2]. LBD - AD and LBD + AD had similar severity and distribution of SYN pathology, subfield CA 2/3 being most severely affected, while CA1/subiculum and entorhinal cortex (ERC) were the most affected regions in AD. Tau pathology in both LBD - AD and LBD + AD was greatest in about two thirds, suggesting that tau burden in LBD was similar to the distribution of SYN in subfield CA 2/3, thus diverging from that in classical AD and contributing to memory dysfunction in LBD. β-Amyloid severity and distribution were similar between LBD + AD and AD.

Plasma Phospho-Tau Identifies Alzheimer's Co-Pathology in Patients with Lewy Body Disease.

ABSTRACTBackgroundAlzheimer's disease co‐pathology is common in dementia with Lewy bodies and Parkinson's disease with dementia (Lewy body disease) and can reliably be detected with positron emission tomography (PET) or cerebrospinal fluid (CSF) biomarkers. Recently developed blood biomarkers are more accessible and less expensive alternatives.ObjectiveTo investigate if plasma phospho‐tau217 and phospho‐tau181 can detect Alzheimer's pathology in Lewy body disease with dementia.MethodsIn this cross‐sectional study we investigated plasma phospho‐tau217 and phospho‐tau181 in 35 patients with Lewy body disease with dementia. Patients underwent tau‐PET imaging (18F‐RO948).ResultsPlasma phospho‐tau217 correlated with plasma phospho‐tau181, CSF phospho‐tau217 (rs = 0.68, P < 0.001), and negatively with CSF β‐amyloid42/40 (rs = −0.52, P = 0.001). Plasma phospho‐tau217 and phospho‐tau181 correlated with tau‐PET signal in the temporal cortex (rs > 0.56, P < 0.001) and predicted abnormal tau‐PET status and β‐amyloid status (area under the curve > 0.78 and > 0.81, respectively).ConclusionPlasma phospho‐tau might be a useful marker for Alzheimer's co‐pathology in Lewy body disease with dementia. © 2020 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.