Impact of Alzheimer's Disease, Lewy Body and Vascular Co-Pathologies on Clinical Transition to Dementia in a National Autopsy Cohort

Cognitive Function Remains Associated With Functional Impairment in Profound Dementia: Alzheimer Disease and Dementia With Lewy Bodies

Background and Objectives

The Baylor Profound Mental Status Examination (BPMSE) was developed to assess cognitive function in the profound stage of dementia. The Clinical Dementia Rating (CDR) scale has been widely used in measuring functional performance in dementia. We aimed to determine whether cognitive function is related to overall functional impairment in profound dementia.

Methods

We selected 864 patients with probable Alzheimer disease (AD) and 25 patients with possible dementia with Lewy Bodies (DLB) cases with profound dementia by Mini-Mental Status Examination or/and clinical global impression. We used BPMSE to measure cognitive function and the CDR sum-of-boxes (CDR-SB) score to determine overall functional status. We used Spearman rank order correlation to examine the univariate association between CDR-SB and BPMSE in the 2 diagnostic groups separately and multivariable regression analysis to investigate whether BPMSE remained associated with functional status after adjustment for age, sex, education, and APOE ε4 genotype. We expected to see an inverse correlation between BPMSE and CDR-SB scores based on the directionality of the rating scale scoring.

Results

In both AD and DLB, total BPMSE scores had a significant inverse correlation with CDR-SB scores (AD: r = -0.453, p < 0.001; DLB: r = -0.489, p = 0.013). It is of interest that in DLB, the "attention" domain of BPMSE had the strongest association with CDR-SB (r = -0.700, p < 0.001) compared with other domains. The multivariable regression models showed that higher BPMSE scores (i.e., better cognitive function) remained significantly correlated with lower CDR-SB scores (i.e., better global function) in AD (CDR-SB: β = -0.340, p < 0.001), but the regression coefficient for BPMSE did not reach significance in the DLB model (CDR-SB: β = -0.298, p = 0.174).

Discussion

In patients with AD and DLB who enter the profound dementia stage, cognitive function is associated with the severity of functional impairment. The lack of significance for DLB in multivariable regression could be due to small sample size because the correlation magnitude is similar to that in AD.

Lewy body pathology modifies risk factors for cerebral amyloid angiopathy when comorbid with Alzheimer's disease pathology

INTRODUCTION

Cerebral amyloid angiopathy (CAA) often accompanies dementia-associated pathologies and is important in the context of anti-amyloid monoclonal therapies and risk of hemorrhage.

METHODS

We conducted a retrospective neuropathology-confirmed study of 2384 participants in the National Alzheimer Coordinating Center cohort (Alzheimer's disease [AD], n = 1175; Lewy body pathology [LBP], n = 316; and mixed AD and LBP [AD-LBP], n = 893). We used logistic regression to evaluate age, sex, education, APOE ε4, neuritic plaques, and neurofibrillary tangles (NFTs) in CAA risk.

RESULTS

APOE ε4 increased CAA risk in all three groups, while younger age and higher NFT stages increased risk in AD and AD-LBP. In AD-LBP, male sex and lower education were additional risk factors. The odds of APOE ε4 carrier homozygosity related to CAA was higher in LBP (25.69) and AD-LBP (9.50) than AD (3.17).

DISCUSSION

AD and LBPs modify risk factors for CAA and should be considered in reviewing the risk of CAA.

HIGHLIGHTS

Lewy body pathology modifies risk factors for cerebral amyloid angiopathy (CAA) when present along with Alzheimer's disease (AD) neuropathology. In the context of anti-amyloid monoclonal therapies and their associated risks for hemorrhage, the risk of underlying CAA in mixed dementia with Lewy body pathology needs to be considered.

Real-World Testing of a Machine Learning-Derived Visual Scale for Tc99m TRODAT-1 for Diagnosing Lewy Body Disease: Comparison with a Traditional Approach Using Semiquantification

Objectives: Abnormal dopamine transporter (DAT) uptake is an important biomarker for diagnosing Lewy body disease (LBD), including Parkinson’s disease (PD) and dementia with Lewy bodies (DLB). We evaluated a machine learning-derived visual scale (ML-VS) for Tc99m TRODAT-1 from one center and compared it with the striatal/background ratio (SBR) using semiquantification for diagnosing LBD in two other centers. Patients and Methods: This was a retrospective analysis of data from a history-based computerized dementia diagnostic system. MT-VS and SBR among normal controls (NCs) and patients with PD, PD with dementia (PDD), DLB, or Alzheimer’s disease (AD) were compared. Results: We included 715 individuals, including 122 NCs, 286 patients with PD, 40 with AD, 179 with DLB, and 88 with PDD. Compared with NCs, patients with PD exhibited a significantly higher prevalence of abnormal DAT uptake using all methods. Compared with the AD group, PDD and DLB groups exhibited a significantly higher prevalence of abnormal DAT uptake using all methods. The distribution of ML-VS was significantly different between PD and NC, DLB and AD, and PDD and AD groups (all p < 0.001). The correlation coefficient of ML-VS/SBR in all participants was 0.679. Conclusions: The ML-VS designed in one center is useful for differentiating PD from NC, DLB from AD, and PDD from AD in other centers. Its correlation with traditional approaches using different scanning machines is also acceptable. Future studies should develop models using data pools from multiple centers for increasing diagnostic accuracy.

Temporal Ordering of Inflammatory Analytes sTNFR2 and sTREM2 in Relation to Alzheimer's Disease Biomarkers and Clinical Outcomes

Inflammatory changes are among the key markers of Alzheimer's disease (AD) related pathological changes. Pro-inflammatory analytes have been related to cognitive decline while others have been related to attenuating neuronal death. Among them, changes in cerebrospinal fluid (CSF) levels of soluble triggering receptor expressed on myeloid cells 2 (sTREM2) and soluble tumor necrosis factor receptor 2 (sTNFR2) have been described as impacting favorable clinical outcomes in AD. We therefore evaluate the effect of CSF sTREM2 and sTNFR2 when taken together on AD biomarkers and longitudinal clinical decline to understand their relative role on impacting AD clinical biomarkers and subsequent clinical outcomes. This longitudinal observational cohort study included 168 amyloid-positive (A+) and p-tau-positive (T+) participants with mild cognitive impairment (MCI) or AD dementia from the Alzheimer's Disease Neuroimaging Initiative (ADNI) with 109 of them having concomitant CSF sTREM2 and sTNFR2 data and 48 A+ T+ participants with MCI from a tertiary memory clinic cohort. An exploratory analysis was performed using data from 86 cognitively normal (CN) participants from ADNI with 72 of them having concomitant CSF AD biomarkers and CSF sTREM2 and sTNFR2 data. General linear models were used to evaluate the effect of sTREM2 and sTNFR2 levels on baseline CSF Aβ42, t-tau, and p-tau, and a linear mixed-effects model was used to assess longitudinal cognitive change after controlling for well-known covariates. Among ADNI A+ T+ MCI and AD dementia participants, CSF sTNFR2 had a stronger association, than CSF sTREM2, with CSF t-tau and p-tau. This was replicated among A+ T+ MCI participants from the memory clinic cohort. On the contrary, among A+ T+ CN participants, CSF sTREM2 explained significant variance in CSF t-tau and p-tau, while CSF sTNFR2 did not. When the effects of CSF sTNFR2 and t-tau on longitudinal cognitive change were taken into account, higher CSF sTREM2 predicted slower cognitive decline in A+ T+ AD dementia participants and faster decline in A+ T+ CN participants. Our results show that given the dynamic changes in sTREM2 and sTNFR2, the clinical impact of these distinct inflammation related biomarkers in tracking AD temporal progression across disease stages are likely to differ.

Oh brother, where art tau? Amyloid, neurodegeneration, and cognitive decline without elevated tau

Mild cognitive impairment (MCI) can be an early manifestation of Alzheimer's disease (AD) pathology, other pathologic entities [e.g., cerebrovascular disease, Lewy body disease, LATE (limbic-predominant age-related TDP-43 encephalopathy)], or mixed pathologies, with concomitant AD- and non-AD pathology being particularly common, albeit difficult to identify, in living MCI patients. The National Institute on Aging and Alzheimer's Association (NIA-AA) A/T/(N) [β-Amyloid/Tau/(Neurodegeneration)] AD research framework, which classifies research participants according to three binary biomarkers [β-amyloid (A+/A-), tau (T+/T-), and neurodegeneration (N+/N-)], provides an indirect means of identifying such cases. Individuals with A+T-(N+) MCI are thought to have both AD pathologic change, given the presence of β-amyloid, and non-AD pathophysiology, given neurodegeneration without tau, because in typical AD it is tau accumulation that is most tightly linked to neuronal injury and cognitive decline. Thus, in A+T-(N+) MCI (hereafter referred to as "mismatch MCI" for the tau-neurodegeneration mismatch), non-AD pathology is hypothesized to drive neurodegeneration and symptoms, because β-amyloid, in the absence of tau, likely reflects a preclinical stage of AD. We compared a group of individuals with mismatch MCI to groups with A+T+(N+) MCI (or "prodromal AD") and A-T-(N+) MCI (or "neurodegeneration-only MCI") on cross-sectional and longitudinal cognition and neuroimaging characteristics. β-amyloid and tau status were determined by CSF assays, while neurodegeneration status was based on hippocampal volume on MRI. Overall, mismatch MCI was less "AD-like" than prodromal AD and generally, with some exceptions, more closely resembled the neurodegeneration-only group. At baseline, mismatch MCI had less episodic memory loss compared to prodromal AD. Longitudinally, mismatch MCI declined more slowly than prodromal AD across all included cognitive domains, while mismatch MCI and neurodegeneration-only MCI declined at comparable rates. Prodromal AD had smaller baseline posterior hippocampal volume than mismatch MCI, and whole brain analyses demonstrated cortical thinning that was widespread in prodromal AD but largely restricted to the medial temporal lobes (MTLs) for the mismatch and neurodegeneration-only MCI groups. Longitudinally, mismatch MCI had slower rates of volume loss than prodromal AD throughout the MTLs. Differences in cross-sectional and longitudinal cognitive and neuroimaging measures between mismatch MCI and prodromal AD may reflect disparate underlying pathologic processes, with the mismatch group potentially being driven by non-AD pathologies on a background of largely preclinical AD. These findings suggest that β-amyloid status alone in MCI may not reveal the underlying driver of symptoms with important implications for enrollment in clinical trials and prognosis.

Heterogeneity of cellular inflammatory responses in ageing white matter and relationship to Alzheimer's and small vessel disease pathologies

White matter lesions (WML) are common in the ageing brain, often arising in a field effect of diffuse white matter abnormality. Although WML are associated with cerebral small vessel disease (SVD) and Alzheimer’s disease (AD), their cause and pathogenesis remain unclear. The current study tested the hypothesis that different patterns of neuroinflammation are associated with SVD compared to AD neuropathology by assessing the immunoreactive profile of the microglial (CD68, IBA1 and MHC‐II) and astrocyte (GFAP) markers in ageing parietal white matter (PARWM) obtained from the Cognitive Function and Ageing Study (CFAS), an ageing population‐representative neuropathology cohort. Glial responses varied extensively across the PARWM with microglial markers significantly higher in the subventricular region compared to either the middle‐zone (CD68 p = 0.028, IBA1 p < 0.001, MHC‐II p < 0.001) or subcortical region (CD68 p = 0.002, IBA1 p < 0.001, MHC‐II p < 0.001). Clasmatodendritic (CD) GFAP⁺ astrocytes significantly increased from the subcortical to the subventricular region (p < 0.001), whilst GFAP⁺ stellate astrocytes significantly decreased (p < 0.001). Cellular reactions could be grouped into two distinct patterns: an immune response associated with MHC‐II/IBA1 expression and CD astrocytes; and a more innate response characterised by CD68 expression associated with WML. White matter neuroinflammation showed weak relationships to the measures of SVD, but not to the measures of AD neuropathology. In conclusion, glial responses vary extensively across the PARWM with diverse patterns of white matter neuroinflammation. Although these findings support a role for vascular factors in the pathogenesis of age‐related white matter neuroinflammation, additional factors other than SVD and AD pathology may drive this. Understanding the heterogeneity in white matter neuroinflammation will be important for the therapeutic targeting of age‐associated white matter damage.

Clinical Profiles of Arteriolosclerosis and Alzheimer Disease at Mild Cognitive Impairment and Mild Dementia in a National Neuropathology Cohort

OBJECTIVE

We sought to evaluate early clinical differences between cerebral arteriolosclerosis (pARTE), Alzheimer disease (pAD), and AD with arteriolosclerosis (ADARTE).

METHODS

Using National Alzheimer's Coordinating Center neuropathology diagnoses, we defined pARTE (n=21), pAD (n=203), and ADARTE (n=158) groups. We compared demographics, medical history, psychometrics, neuropsychiatric symptoms, and apolipoprotein E (APOE) allele variants across neuropathology groups. Retrospective timepoints were first evaluation with Global Clinical Dementia Rating (CDR) score of 0.5 and 1.0, via the CDR Dementia Staging Instrument, corresponding to mild cognitive impairment (MCI) and mild dementia, respectively.

RESULTS

In MCI, clinical differences were minimal but pARTE subjects were older, had later onset cognitive decline, and progressed less severely than pAD. In mild dementia, pAD subjects were younger and had earlier onset of decline. Neuropsychiatric (depression) and psychometric (Logical Memory Delayed Recall, Trails B) differences also emerged between the groups. In MCI, APOE4 associated with worse Logical Memory Delayed Recall in pAD and ADARTE. In mild dementia, APOE4 associated with better animal fluency in pAD, but with better Trails A performance and more neuropsychiatric symptoms (Neuropsychiatric Inventory Questionnaire) in ADARTE.

CONCLUSIONS

Differences between pARTE, pAD, and ADARTE emerge at mild dementia rather than MCI. APOE4 has varied cognitive and psychiatric impact dependent on neuropathology group and stage.

Criteria for Psychosis in Major and Mild Neurocognitive Disorders: International Psychogeriatric Association (IPA) Consensus Clinical and Research Definition

Psychosis is common among individuals with neurocognitive disorders, is difficult to manage, and causes considerable burden and stress to patients and caregivers. Developing effective treatments is a substantial unmet medical need but research has been slowed by the need for updated consensus diagnostic criteria. To address this need, the International Psychogeriatrics Association initiated a process to develop criteria for clinical use, research, and treatment development efforts. The process included clinical, regulatory, and industry stakeholders as well as input from a global network of experts in geriatric psychiatry responding to two surveys (N = 336). Results from the consensus process confirmed that clinicians wanted elaboration of aspects of the definition proposed by Jeste and Finkel in 2000 to ensure that the criteria are applied appropriately. Based on discussions, the survey, and emerging research, criteria were revised to apply to psychosis occurring with all major and mild neurocognitive disorders. Other important changes include providing examples of hallucinations and delusions and clarifying time course, impact, and exclusionary criteria. This definition of psychosis in major and mild neurocognitive disorders can be used to advance many types of research including development of much needed pharmacologic and nonpharmacologic interventions for psychosis in patients with neurocognitive disorders.

Spatial patterns of correlation between cortical amyloid and cortical thickness in a tertiary clinical population with memory deficit

To estimate regional Alzheimer disease (AD) pathology burden clinically, analysis methods that enable tracking brain amyloid or tau positron emission tomography (PET) with magnetic resonance imaging (MRI) measures are needed. We therefore developed a robust MRI analysis method to identify brain regions that correlate linearly with regional amyloid burden in congruent PET images. This method was designed to reduce data variance and improve the sensitivity of the detection of cortical thickness-amyloid correlation by using whole brain modeling, nonlinear image coregistration, and partial volume correction. Using this method, a cross-sectional analysis of 75 tertiary memory clinic AD patients was performed to test our hypothesis that regional amyloid burden and cortical thickness are inversely correlated in medial temporal neocortical regions. Medial temporal cortical thicknesses were not correlated with their regional amyloid burden, whereas cortical thicknesses in the lateral temporal, lateral parietal, and frontal regions were inversely correlated with amyloid burden. This study demonstrates the robustness of our technique combining whole brain modeling, nonlinear image coregistration, and partial volume correction to track the differential correlation between regional amyloid burden and cortical thinning in specific brain regions. This method could be used with amyloid and tau PET to assess corresponding cortical thickness changes.

Cognitive tests aid in clinical differentiation of Alzheimer's disease versus Alzheimer's disease with Lewy body disease: Evidence from a pathological study

INTRODUCTION

Clinical differentiation between Alzheimer's disease (AD) and AD with Lewy body disease (LBD) is relatively imprecise. The current study examined pathologically confirmed group differences in neuropsychological functioning, and the classification ability of specific tests.

METHODS

Fifty-one participants with postmortem diagnoses of AD (n = 34) and AD plus LBD (n = 17) were drawn from the Predictors Study. One-way analyses of variance (ANOVAs) and χ² analyses examined group differences in neuropsychological performance. Binary logistic regressions examined predictive utility of specific tests for pathological diagnosis.

RESULTS

Individuals with AD had better visuoconstruction (P = .006), phonemic fluency (P = .08), and processing speed than AD plus LBD (P = .013). No differences were found in memory, naming, semantic fluency, or set-switching. Processing speed and visuoconstruction predicted pathologic group (P = .03).

DISCUSSION

Processing speed and visuoconstruction predicted postmortem diagnosis of AD versus AD plus LBD. Current results offer guidance in the selection and interpretation of neuropsychological tests to be used in the differential diagnosis of early dementia.

Cohort Effects in Progression Rate on Cognitive and Functional Measures in an Alzheimer's Disease Clinical Cohort

BACKGROUND

Accurate prediction of Alzheimer's disease (AD) cognitive and functional outcomes in clinical research requires consistent underlying rates of change over time.

OBJECTIVE

To examine cohort effects in AD progression rate over five years of follow-up using a clinical database of probable AD patients.

METHODS

Baseline characteristics of three cohorts enrolled from 1995-1999, 2000-2004, and 2005-2009 were compared using ANOVA and chi-square tests. Differences in 5-year decline on the Mini-Mental State Examination (MMSE), Alzheimer's Disease Assessment Scale-Cognitive Subscale (ADAS-Cog) and Clinical Dementia Rating Scale Sum of Boxes (CDR-SB), the Lawton and Brody Physical Self-maintenance Scale (PSMS), and Activities of Daily Living Scale (ADL) were assessed using longitudinal mixed effects regression, adjusting for age, sex, education, and other relevant clinical characteristics.

RESULTS

Cohorts 1 (n = 287), 2 (n = 257), and 3 (n = 374) did not differ on age, race, APOE genotype, or cognitive and functional measures. Educational attainment increased over time (13.4, 14.1, and 14.5 years, respectively, p < 0.001). Anti-dementia drug use at baseline was less common in Cohort 1 (32.2% versus 65.0%, and 66.8%, p < 0.001). The rate of decline in MMSE and CDR-SB did not differ across cohorts. ADAS-Cog scores for Cohort 2 declined more slowly than Cohort 3 (Btime ×cohort2 = -0.91 ± 0.35, p = 0.009), whereas Cohort 1 did not differ from cohort 3 (reference). Cohorts 1 and 2 differed from Cohort 3 in progression rate on the PSMS, but not the IADL.

CONCLUSIONS

There were no consistent temporal trends in progression rates over time. Longitudinal data over 15-20 years may be confidently pooled for outcomes analysis, but unexplained variability in rate of decline on some measures may occur.

Rapidly Progressive Alzheimer's Disease in Two Distinct Autopsy Cohorts

BACKGROUND

A rapidly progressive phenotype of Alzheimer's disease (AD) has been described in some prion disease cohorts. Limited information regarding rapidly progressive AD (rpAD) is available from longitudinal national cohorts.

OBJECTIVE

To compare the clinical characteristics of rpAD in two different national cohorts.

METHODS

A retrospective analysis was performed on AD subjects with available neuropathology in the National Alzheimer's Coordinating Center (NACC) database and among neuropathologically characterized AD cases from the National Prion Disease Pathology Surveillance Center (NPDPSC) that were evaluated for suspected prion disease. In the NACC cohort, rpAD was delineated by the lower 10th percentile of follow up duration from pre-dementia to death duration among subjects meeting pathological diagnosis of AD.

RESULTS

rpAD from the NPDPSC had a shorter mean symptom duration than the NACC identified rpAD cases (11.6 months versus 62.4 months) and were also younger at the time of their death (60.0 versus 81.8 years). NACC identified rpAD subjects, beginning from a predementia stage, had slower rate of MMSE change per year than NPDPSC cases (2.5 versus 6.0 points).

CONCLUSIONS

rpAD constitute an important subset of AD subjects in whom a rapid course of symptomatic clinical decline is noted, as confirmed in both national cohorts. rpAD was best characterized by survival time (≤3 years), as there were clear differences between the rpAD cohorts in terms of symptom duration, age at death, and MMSE change per year, likely due to the strong selection biases. rpAD could shed light on the biology of rate of progression in AD.

Neuroscience learning from longitudinal cohort studies of Alzheimer's disease: Lessons for disease-modifying drug programs and an introduction to the Center for Neurodegeneration and Translational Neuroscience

The development of disease-modifying therapies for Alzheimer's disease is an urgent public health emergency. Recent failures have highlighted the significant challenges faced by drug-development programs. Longitudinal cohort studies are ideal for promoting understanding of this multifactorial, slowly progressive disease. In this section of the special edition, we review several important lessons from longitudinal cohort studies which should be considered in disease-modifying therapy development. In the final section, we introduce the clinical cohort of the Center for Neurodegeneration and Translational Neuroscience. This newly established longitudinal study aims to provide new insights into the neuroimaging and biological marker (biomarkers) correlates of cognitive decline in early Alzheimer's disease and Parkinson's disease (PD).

Impact of the Presence of Select Cardiovascular Risk Factors on Cognitive Changes among Dementia Subtypes

BACKGROUND

Studies have shown select associations between cardiovascular risk factors and dementia, but mostly focused on Alzheimer's Disease (AD).

OBJECTIVE

We enhance these works by evaluating the relationship between the presence of cardiovascular risk factors and the rate of cognitive decline, measured using the Mini-Mental State Examination (MMSE) and Clinical Dementia Rating Sum of Boxes (CDR-SUM) on four common dementia subtypes (AD, dementia with Lewy bodies (DLB), frontotemporal dementia (FTD), and vascular dementia (VaD), as well as non-demented elderly individuals (normal)).

METHOD

We used generalized linear mixed models with random intercepts to account for correlation at the patient and center levels for each dementia subtype adjusting for time since initial visit, baseline cognitive score, age, and demographic factors. The cardiovascular risk factors evaluated included body mass index, diabetes, years of smoking, atrial fibrillation, hypertension, and hypercholesterolemia.

RESULTS

Patients diagnosed with AD (n=1899), DLB (n=65), FTD (n=168), or VaD (n=13); or lacked cognitive impairment (normal) (n=3583) were evaluated using data from the National Alzheimer's Coordinating Centers. Cardiovascular risk factors were associated with select dementia subtypes including AD and FTD. Using MMSE and CDR-SUM, recent or active hypertension and hypercholesterolemia were associated with a slower cognitive decline for AD patients, while higher body mass index and years of smoking were associated with a slower cognitive decline for FTD patients. However, several cardiovascular factors demonstrated associations with more rapid cognitive decline.

CONCLUSION

These results demonstrate disease specific associations and can provide clinicians guidance on predicted cognitive changes at the group level using information about cardiovascular risk factors.

Mixed neuropathologies and associations with domain-specific cognitive decline

OBJECTIVE

To test whether decline in specific cognitive domains associated with Alzheimer disease neuropathologic change (ADNC) is modified by co-occurrence of other neuropathologies such as Lewy body disease (LBD) or vascular brain injury (VBI).

METHODS

Data came from 1,603 autopsied participants evaluated at US Alzheimer's Disease Centers. Standardized z scores in memory, attention, language, and executive function were derived from neuropsychological test scores assessed at each annual visit. Multivariable linear mixed-effects models assessed associations between neuropathologies and longitudinal trajectories of domain scores.

RESULTS

Compared to other participants, those with ADNC + LBD generally had worse cognitive trajectories, particularly lower initial executive function and faster attention decline. Participants with ADNC + VBI typically had less impairment and slower decline. Interactions were significant between LBD and ADNC for memory (p = 0.046) and between VBI and ADNC for language (p = 0.03); decline was slower than expected if these neuropathologies acted additively on the rate of decline. In secondary models, these interactions were limited to those with high ADNC (but not intermediate ADNC). In a subset of 260 participants with data on microinfarct location, cortical and subcortical microinfarcts were associated with decline in memory, language, and executive function in those without ADNC, but this effect was reduced among those with ADNC.

CONCLUSIONS

ADNC + LBD (but not ADNC + VBI) was associated with poorer executive function and attention compared to other pathology groupings. However, the effect of co-occurring pathologies on cognitive trajectories may depend on the severity of ADNC. Future studies using antemortem biomarkers should seek to replicate these neuropathologic observations.