Associations between diffusion MRI microstructure and cerebrospinal fluid markers of Alzheimer's disease pathology and neurodegeneration along the Alzheimer's disease continuum

Introduction

White matter (WM) degeneration is a critical component of early Alzheimer's disease (AD) pathophysiology. Diffusion-weighted imaging (DWI) models, including diffusion tensor imaging (DTI), neurite orientation dispersion and density imaging (NODDI), and mean apparent propagator MRI (MAP-MRI), have the potential to identify early neurodegenerative WM changes associated with AD.

Methods

We imaged 213 (198 cognitively unimpaired) aging adults with DWI and used tract-based spatial statistics to compare 15 DWI metrics of WM microstructure to 9 cerebrospinal fluid (CSF) markers of AD pathology and neurodegeneration treated as continuous variables.

Results

We found widespread WM injury in AD, as indexed by robust associations between DWI metrics and CSF biomarkers. MAP-MRI had more spatially diffuse relationships with Aβ42/40 and pTau, compared with NODDI and DTI.

Discussion

Our results suggest that WM degeneration may be more pervasive in AD than is commonly appreciated and that innovative DWI models such as MAP-MRI may provide clinically viable biomarkers of AD-related neurodegeneration in the earliest stages of AD progression.

Effects of nitroglycerin-induced vasodilation on elastic and muscular artery stiffness in older Veterans

Vascular smooth muscle tone may play an important role in the physiology of increased arterial stiffness that occurs with aging. This study evaluated the impact of smooth muscle tone on arterial stiffness in older individuals following nitroglycerin-induced vasodilation in elastic and muscular arteries. Forty older Veterans (≥60 years old) without known cardiovascular disease were included in this study. Twenty Veterans were included as hypertensive participants (70.8 ± 6.6 years, 10 females), and 20 were included as normotensive controls (72.0 ± 9.3 years, 8 females). Nitroglycerin (NTG)-induced changes in arterial stiffness were measured locally with vascular ultrasound in the carotid and brachial arteries and regionally by carotid-femoral pulse wave velocity (cfPWV) with tonometry. With NTG treatment, both hypertensive participants and normotensive controls Veterans showed increased carotid PWV (6.4 ± 1.3 m/s to 7.2 ± 1.4 m/s, Δ 0.8 ± 1.1 m/s, p = 0.007) and cfPWV (8.6 ± 1.9 m/s to 9.5 ± 2.4 m/s, Δ 0.9 ± 2.3 m/s, p = 0.020) but did not show changes in brachial PWV (11.2 ± 2.4 m/s to 11.1 ± 2.2 m/s, Δ -0.2 ± 2.5 m/s, p = 0.72). The carotid artery was dilated more in control participants than hypertensive Veterans (Δ 0.54 ± 0.19 mm vs. 0.42 ± 0.12 mm, p = 0.022). Brachial artery dilation was similar between the two groups (Δ 0.55 ± 0.26 mm vs. 0.51 ± 0.20 mm, p = 0.46). In older Veterans without known cardiovascular disease, NTG-induced vasodilation increased elastic artery stiffness but did not change muscular artery stiffness. Increased central arterial stiffness and a decrease in the arterial stiffness gradient could offset some of the benefits of lowering blood pressure in older patients who are prescribed vasodilators as an antihypertensive therapy. Elastic artery stiffening with vasodilation warrants further investigation, as it may be important for antihypertensive medication selection and influence CVD development.

Training dementia care professionals to help caregivers improve the management of behavioral and psychological symptoms of dementia using the DICE Approach: A pilot study

Most persons living with dementia (PLWD) exhibit behavioral or psychological symptoms of dementia (BPSD) over the course of the illness. The DICE Approach (DICE) is a framework that enables caregivers to identify, evaluate, and manage BPSD. This pilot pre-post test study examined the effects of DICE training on dementia care professionals' self-efficacy, knowledge, and attitudes regarding care of patients with BPSD. Participants underwent either in-person DICE training or, during the pandemic, online training. Case consultations were offered as additional learning opportunities in challenging situations. Of 134 participants in the trainings, 122 (91.0%) provided survey data for one or more instruments before and after training. Participants experienced significant improvement in knowledge and attitudes with respect to BPSD and improvement in self-efficacy with respect to helping caregivers respond to BPSD. Training dementia care professionals in DICE can improve their capacity to support caregivers in the management of BPSD.

Trajectory of clinical symptoms in relation to amyloid chronicity

Introduction

While it is generally appreciated that amyloid precedes symptomatic Alzheimer's disease (AD) by decades, a greater understanding of this timeline may increase prognostic accuracy, planning, and care of persons who are on the AD continuum.

Methods

We examined trajectories of Clinical Dementia Rating-Sum of Boxes (CDR-SB) relative to estimated years of amyloid positivity (A+) in n = 123 participants who were all A+ based on [C-11]Pittsburgh compound B positron emission tomography.

Results

The average amyloid chronicity at CDR-SB of 2.5 was 20.1 years. The average trajectory of CDR-SB accelerated after 10 years of elevated amyloid and varied greatly between 10 and 30 years. Exploratory analyses suggested that older age and higher volume of white matter hyperintensities shortened the interval between amyloid onset and cognitive impairment.

Discussion

The recontextualization of amyloid burden into the time domain will facilitate studies of disease progression, the influence of co-pathology, and factors that hasten or slow cognitive impairment.

Inflammation, tau pathology, and synaptic integrity associated with sleep spindles and memory prior to β-amyloid positivity

STUDY OBJECTIVES

Fast frequency sleep spindles are reduced in aging and Alzheimer's disease (AD), but the mechanisms and functional relevance of these deficits remain unclear. The study objective was to identify AD biomarkers associated with fast sleep spindle deficits in cognitively unimpaired older adults at risk for AD.

METHODS

Fifty-eight cognitively unimpaired, β-amyloid-negative, older adults (mean ± SD; 61.4 ± 6.3 years, 38 female) enriched with parental history of AD (77.6%) and apolipoprotein E (APOE) ε4 positivity (25.9%) completed the study. Cerebrospinal fluid (CSF) biomarkers of central nervous system inflammation, β-amyloid and tau proteins, and neurodegeneration were combined with polysomnography (PSG) using high-density electroencephalography and assessment of overnight memory retention. Parallelized serial mediation models were used to assess indirect effects of age on fast frequency (13 to <16Hz) sleep spindle measures through these AD biomarkers.

RESULTS

Glial activation was associated with prefrontal fast frequency sleep spindle expression deficits. While adjusting for sex, APOE ε4 genotype, apnea-hypopnea index, and time between CSF sampling and sleep study, serial mediation models detected indirect effects of age on fast sleep spindle expression through microglial activation markers and then tau phosphorylation and synaptic degeneration markers. Sleep spindle expression at these electrodes was also associated with overnight memory retention in multiple regression models adjusting for covariates.

CONCLUSIONS

These findings point toward microglia dysfunction as associated with tau phosphorylation, synaptic loss, sleep spindle deficits, and memory impairment even prior to β-amyloid positivity, thus offering a promising candidate therapeutic target to arrest cognitive decline associated with aging and AD.

Principal components from untargeted cerebrospinal fluid metabolomics associated with Alzheimer's disease biomarkers

Studying the correlation between cerebrospinal fluid (CSF) metabolites and the Alzheimer's Disease (AD) biomarkers may offer a window to the alterations of the brain metabolome and unveil potential biological mechanisms underlying AD. In this analysis, 308 CSF metabolites from 338 individuals of Wisconsin Registry for Alzheimer's Prevention and Wisconsin Alzheimer's Disease Research Center were included in a principal component analysis (PCA). The resulted principal components (PCs) were tested for association with CSF total tau (t-tau), phosphorylated tau (p-tau), amyloid β 42 (Aβ42), and Aβ42/40 ratio using linear regression models. Significant PCs were further tested with other CSF NeuroToolKit (NTK) and imaging biomarkers. Using a Bonferroni corrected p < 0.05, 5 PCs were significantly associated with CSF p-tau and t-tau and 3 PCs were significantly associated with CSF Aβ42. Pathway analysis suggested that these PCS were enriched in 6 pathways, including metabolism of caffeine and nicotinate and nicotinamide. This study provides evidence that CSF metabolites are associated with AD pathology through core AD biomarkers and other NTK markers and suggests potential pathways to follow up in future studies.

Training professional caregivers to screen for report of cognitive changes in persons with intellectual disability

Introduction

By age 60, 60% of adults with Down syndrome (DS) have dementia. Detecting dementia in persons with intellectual disability (ID) can be challenging because their underlying cognitive impairment can confound presentation of dementia symptoms and because adults with ID may have difficulty reporting symptoms. The National Task Group Early Detection Screen for Dementia (NTG-EDSD) was developed to aid detection of report of cognitive impairment in adults with ID. We implemented an educational curriculum using the NTG-EDSD and evaluated the impact of the intervention on professional caregivers' self-assessed capacity to identify persons with ID and dementia.

Methods

We held five in-person training sessions for professional caregivers of persons with ID, partnering with various managed care organizations and social services agencies. We assessed knowledge and attitudes at baseline; immediately after training; and 1 week, 1 month, and 6 months after training.

Results

A total of 154 direct care workers, case managers, health-care providers, and other social services staff attended the trainings. Satisfaction with the NTG-EDSD training was high; 94% of attendees agreed or strongly agreed that they could use the NTG-EDSD with their clients. After training, attendees reported a marked increase in confidence in their ability to track various health circumstances and detect functional decline in their clients, although some gains were not sustained over time. As a result of the training, one managed care organization made the NTG-EDSD a standard part of its assessment of adults with DS starting at age 40.

Discussion

Social services and health-care professionals can learn to document signs of cognitive decline in adults with ID using the NTG-EDSD. Attendees were highly satisfied with the training, experienced an increase in confidence in their care of persons with ID, and found the NTG- EDSD feasible to use. Because not all gains were sustained over time, booster trainings may be necessary.

The Wisconsin Alzheimer's Institute Dementia Diagnostic Clinic Network: A community of practice to improve dementia care

BACKGROUND

The Wisconsin Alzheimer's Institute (WAI) Dementia Diagnostic Clinic Network is a community of practice formed in 1998 as a collaboration of community-based clinics from various healthcare systems throughout the state. Its purpose is to promote the use of evidence-based strategies to provide high quality care throughout Wisconsin for people with dementia. The purpose of this study is to describe the use of a community of practice to facilitate education of healthcare providers on best practices in dementia care, and the implementation of an interprofessional approach to diagnose and manage dementia and related disorders.

METHODS

Cross-sectional study of the members of the WAI's Dementia Diagnosis Clinic Network. Characteristics of clinics and healthcare teams, learners' participation in educational events and educational outcomes were collected from evaluation forms. Number and characteristics of patients seen in the memory clinics were collected from de-identified data forms submitted by members to a centralized location for data analysis.

RESULTS

The clinic network currently has 38 clinics affiliated with 26 different healthcare systems or independent medical groups in 21 of 72 Wisconsin counties. Most (56%) are based in primary care, 15% in psychiatry, and 29% in neurology. Between 2018 and 2021, we received data on 4710 patients; 92% were ≥65 years old, 60% were female, and 92% were white. Network members meet in-person twice a year to learn about innovations in the field of dementia care and to share best practices. Educational events associated with the network are shown to be relevant, useful, and improve knowledge and skills of participants.

CONCLUSION

Communities of practice provide added value via shared best practices and educational resources, continuing education of the health workforce, continuous quality improvement of clinical practices, and adoption of new diagnostic and management approaches in dementia care.

Management of Dementia

PURPOSE OF REVIEW

This article describes an approach to managing patients following a diagnosis of dementia, including medical management, nonpharmacologic strategies, safety interventions, caregiver support, mobilization of community resources, and advanced care planning.

RECENT FINDINGS

Dementia clinical syndromes are frequently caused by mixed pathologies, leading to varied clinical presentations that include memory loss, behavioral changes, communication challenges, safety concerns, and loss of independent function. Medications for treating dementia currently target cognitive and behavioral symptoms, although disease-modifying therapies for Alzheimer disease may be making their way into widespread clinical practice soon. Identification and treatment of co-occurring medical problems, such as obstructive sleep apnea, adverse medication effects, mood disorders, hearing loss, pain, alcohol misuse, and vascular risk factors, may mitigate the impact of these conditions on cognitive decline. Mobilization of clinical and community-based interprofessional teams will ensure that people with dementia and their care partners have the expertise, support, and access to resources they need. Addressing goals of care early in the disease course will allow people with dementia to contribute to their care plan by expressing their wishes.

SUMMARY

Developing a structured approach to treating common causes of dementia and related comorbid medical conditions, identifying a local network of interprofessional clinical and community-based referrals, and providing readily available educational resources will help clinicians provide quality dementia care management that extends beyond the clinic visit. Encouraging patients and families to engage in clinical research will advance the identification of effective therapies, preventive strategies, and quality care models for the future.

Crosswalk study on blood collection-tube types for Alzheimer's disease biomarkers

INTRODUCTION

Blood-based Alzheimer's disease (AD) biomarkers show promise, but pre-analytical protocol differences may pose problems. We examined seven AD blood biomarkers (amyloid beta [A β ] 42 ,A β 40 ,phosphorylated tau [ p - ta u 181 , total tau [t-tau], neurofilament light chain [NfL],A β 42 40 , andp - ta u 181 A β 42 ) in three collection tube types (ethylenediaminetetraacetic acid [EDTA] plasma, heparin plasma, serum).

METHODS

Plasma and serum were obtained from cerebrospinal fluid or amyloid positron emission tomography-positive and -negative participants (N = 38) in the Wisconsin Registry for Alzheimer's Prevention. We modeled AD biomarker values observed in EDTA plasma versus heparin plasma and serum, and assessed correspondence with brain amyloidosis.

RESULTS

Results suggested bias due to tube type, but crosswalks are possible for some analytes, with excellent model fit for NfL (R 2 = 0.94), adequate for amyloid (R 2 = 0.40-0.69), and weaker for t-tau (R 2 = 0.04-0.42) andp - ta u 181 (R 2 = 0.22-0.29). Brain amyloidosis differentiated several measures, especially EDTA plasmapTa u 181 A β 42 (d = 1.29).

DISCUSSION

AD biomarker concentrations vary by tube type. However, correlations for some biomarkers support harmonization across types, suggesting cautious optimism for use in banked blood.

Cerebrospinal Fluid Sphingomyelins in Alzheimer's Disease, Neurodegeneration, and Neuroinflammation

BACKGROUND

Sphingomyelin (SM) levels have been associated with Alzheimer's disease (AD), but the association direction has been inconsistent and research on cerebrospinal fluid (CSF) SMs has been limited by sample size, breadth of SMs examined, and diversity of biomarkers available.

OBJECTIVE

Here, we seek to build on our understanding of the role of SM metabolites in AD by studying a broad range of CSF SMs and biomarkers of AD, neurodegeneration, and neuroinflammation.

METHODS

Leveraging two longitudinal AD cohorts with metabolome-wide CSF metabolomics data (n = 502), we analyzed the relationship between the levels of 12 CSF SMs, and AD diagnosis and biomarkers of pathology, neurodegeneration, and neuroinflammation using logistic, linear, and linear mixed effects models.

RESULTS

No SMs were significantly associated with AD diagnosis, mild cognitive impairment, or amyloid biomarkers. Phosphorylated tau, neurofilament light, α-synuclein, neurogranin, soluble triggering receptor expressed on myeloid cells 2, and chitinase-3-like-protein 1 were each significantly, positively associated with at least 5 of the SMs.

CONCLUSION

The associations between SMs and biomarkers of neurodegeneration and neuroinflammation, but not biomarkers of amyloid or diagnosis of AD, point to SMs as potential biomarkers for neurodegeneration and neuroinflammation that may not be AD-specific.

Using academic detailing to enhance the knowledge, skills and attitudes of clinicians caring for patients with behavioral and psychological symptoms of dementia

INTRODUCTION

Approximately 90% of persons with dementia experience behavioral and psychological symptoms of dementia (BPSD) over the course of their illness. Primary care clinicians often provide care as specialty geriatric-medicine or -psychiatry consultation may be difficult to obtain. Academic detailing (AD) is an evidence-based educational approach for engaging and persuading healthcare professionals to make changes in their practice (Avorn 2017). We sought to enhance the knowledge, skills and attitudes of providers' care of patients with BPSD using the AD model in primary care.

METHODS

We implemented AD in an urban clinic serving a largely Black community and a rural clinic serving a large, White community. Each AD visit included didactic content, case discussion, and consultation regarding patients with BPSD. Eleven visits over 18 months are planned for each site. Outcome measures include a 10-item multiple-choice assessment of knowledge and an adaptation of the General Practitioners Attitude and Confidence Scale for Dementia (GPACS-D) (Mason et al. 2019) at baseline before training, and 6 and 18 months, and Likert-scale measurement of acceptability at 6 and 18 months, all self-report.

RESULTS

We present interim data. Five urban and 14 rural providers completed baseline assessments. Providers were mostly White (95%) and Non-Hispanic (100%); 47% were female. Urban and rural providers had similar baseline BPSD knowledge (mean (SD) of correct answers, 5.4 (1.7) for rural, and 5.0 (2.6) for urban). The adapted GPACS-D, where higher score indicates more confidence, showed less confidence (mean score 11.4 versus 16.6, p=0.01) in urban versus rural providers. The overall attitudes score indicate there may be more confidence in treating BPSD at baseline among the slightly older rural providers as compared to their urban colleagues. Thus far, eight of 22 planned AD visits have been completed; 6-month assessments are forthcoming and will be presented.

DISCUSSION

Academic detailing may be a feasible and effective way of increasing self-reported knowledge and skills and improving self-reported attitude of primary care providers responsible for the care of patients with BPSD. The pilot data collected in this study will inform the design of a larger study to measure the impact of AD on patient outcomes.

Interaction of amyloid and tau on cortical microstructure in cognitively unimpaired adults

INTRODUCTION

Neurite orientation dispersion and density imaging (NODDI), a multi-compartment diffusion-weighted imaging (DWI) model, may be useful for detecting early cortical microstructural alterations in Alzheimer's disease prior to cognitive impairment.

METHODS

Using neuroimaging (NODDI and T1-weighted magnetic resonance imaging [MRI]) and cerebrospinal fluid (CSF) biomarker data (measured using Elecsys® CSF immunoassays) from 219 cognitively unimpaired participants, we tested the main and interactive effects of CSF amyloid beta (Aβ)42 /Aβ40 and phosphorylated tau (p-tau) on cortical NODDI metrics and cortical thickness, controlling for age, sex, and apolipoprotein E ε4.

RESULTS

We observed a significant CSF Aβ42 /Aβ40 × p-tau interaction on cortical neurite density index (NDI), but not orientation dispersion index or cortical thickness. The directionality of these interactive effects indicated: (1) among individuals with lower CSF p-tau, greater amyloid burden was associated with higher cortical NDI; and (2) individuals with greater amyloid and p-tau burden had lower cortical NDI, consistent with cortical neurodegenerative changes.

DISCUSSION

NDI is a particularly sensitive marker for early cortical changes that occur prior to gross atrophy or development of cognitive impairment.

Effectively training dementia care specialists and other dementia professionals on using the DICE ApproachTM with caregivers to improve the management of behavioral and psychological symptoms of dementia

INTRODUCTION

Most persons living with dementia will exhibit at least one behavioral or psychological symptom of dementia (BPSD) (Kales, et al., 2015). As brain pathology progresses, challenging behaviors can increase in frequency and severity, causing an increase in caregiver stress and burden. Furthermore, BPSD can result in unplanned hospitalizations and unnecessary use of psychotropic medications. Non-pharmacological management of BPSD should be the first line of treatment. The DICE (Describe, Investigate, Create, Evaluate) Approach^TM was developed by experts from the University of Michigan and John Hopkins University, to help caregivers learn how to identify and manage BPSD. This project describes a statewide implementation of the DICE approach with community-based dementia care providers.

METHODS

From September 2017 to April 2020, we held four DICE trainings (three in-person trainings, one web-based training) for Dementia Care Specialists (DCSs) and other dementia care professionals who work directly with family caregivers of people with dementia in Wisconsin. We assessed trainees' knowledge and attitudes from the Dementia Attitudes Scale (DAS) and the Knowledge about Memory Loss and Care test (KAML-C) at baseline of training, immediately after training, and six months after training. Consultations were provided to address challenging cases.

RESULTS

Participants (N=136) in both in-person and online DICE trainings experienced significant changes in knowledge, self-efficacy and attitudes from baseline to post-training (immediately after training) assessments (p<.01) (see Table 2 for details). Narrative feedback from trainees was generally very positive. Trainees used DICE with 165 caregivers who were primarily non-Hispanic white (92%) females (74.4%) from an urban location (68.1%), caring for their spouse (52.7%) (Table 1).

DISCUSSION

By using the DICE approach with caregivers of persons with dementia, Wisconsin's DCSs and other dementia professionals are uniquely positioned to help reduce risks associated with BPSD, including the use of psychotropic medications. Training satisfaction was high, knowledge about BPSD increased, and attitudes improved. The DICE trainings prepared trainees to implement this intervention with 165 family caregivers. A follow-up survey will explore the real-world application of DICE, including barriers to its use and modifications made in communities across the state.

Quality measures in dementia care across a network of memory clinics: An implementation study

BACKGROUND

In 2015 the American Academy of Neurology and American Psychiatric Association updated the Dementia Management Measurement Set from 2009. Out of the nine measures proposed, four have been included by the Centers for Medicare and Medicaid Services (CMS) in their Merit-Based Incentive Payment System, which is used to determine payment adjustments in pay-for-reporting program. In 2018, the Wisconsin Alzheimer's Institute (WAI) developed a process to track the performance of these measures across the WAI Dementia Diagnostic Clinic Network, which consists of 44 statewide clinics across 24 healthcare systems.

METHOD

In September 2018, WAI launched the following implementation strategies to improve adoption of the quality measures: audit and feedback, new de-identified forms, and development of a codebook with definitions and examples on how to fill the new forms. Clinics submit de-identified forms containing demographics, diagnosis and process measures that are used to calculate performance on the quality measures. Descriptive analyses were performed, and performance was calculated according to criteria set by CMS.

RESULT

Over 24 months, 23 clinics have submitted information on 3,247 patients. Early adopters demonstrated a high performance on the measures, but as more clinics participate, the distribution has shown regression to the mean (Table 1). When comparing clinic performance between Oct 2019 - Oct 2020 with CMS benchmarks for 2020, the percentage of clinics performing above the CMS average were: 68% for measure #2; 91% for measure #3; 48% for measure #4; and 86% for measure #5 (Figure). Variations in performances have been attributed to unique characteristics of each clinic, for example, some do not follow-up individuals and only provide recommendations to primary care providers; this lowers their metrics in measures that require management of behaviors or conditions.

CONCLUSION

Implementation of the quality measures across the WAI network has been facilitated by the use of clinical care models that promote interdisciplinary care. Further research is required to explore additional mechanisms that increase participation of clinics, and to develop new data collection methods that can explore the impact of these measures on health outcomes.

Circulating Klotho Is Higher in Cerebrospinal Fluid than Serum and Elevated Among KLOTHO Heterozygotes in a Cohort with Risk for Alzheimer's Disease

BACKGROUND

Klotho is a longevity and neuroprotective hormone encoded by the KLOTHO gene, and heterozygosity for the KL-VS variant confers a protective effect against neurodegenerative disease.

OBJECTIVE

Test whether klotho concentrations in serum or cerebrospinal fluid (CSF) vary as a function of KLOTHO KL-VS genotype, determine whether circulating klotho concentrations from serum and CSF differ from one another, and evaluate whether klotho levels are associated with Alzheimer's disease risk factors.

METHODS

Circulating klotho was measured in serum (n = 1,116) and CSF (n = 183) of cognitively intact participants (aged 62.4 ± 6.5 years; 69.5% female). KLOTHO KL-VS zygosity (non-carrier; heterozygote; homozygote) was also determined. Linear regression was used to test whether klotho hormone concentration varied as a function of KL-VS genotype, specimen source, and demographic and clinical characteristics.

RESULTS

Serum and CSF klotho were higher in KL-VS carriers than non-carriers. Klotho concentration was higher in CSF than in serum. Females had higher serum and CSF klotho, while younger age was associated with higher klotho in CSF.

CONCLUSION

In a cohort enriched for risk for Alzheimer's disease, heterozygotic and homozygotic carriers of the KL-VS allele, females, and younger individuals have higher circulating klotho. Fluid source, KL-VS genotype, age, and sex should be considered in analyses of circulating klotho on brain health.

Cerebrovascular stiffness and flow dynamics in the presence of amyloid and tau biomarkers

INTRODUCTION

This work investigated the relationship between cerebrovascular disease (CVD) markers and Alzheimer's disease (AD) biomarkers of amyloid beta deposition, and neurofibrillary tau tangles in subjects spanning the AD clinical spectrum.

METHODS

A total of 136 subjects participated in this study. Four groups were established based on AD biomarker positivity from positron emission tomography (amyloid [A] and tau [T]) and clinical diagnosis (cognitively normal [CN] and impaired [IM]). CVD markers were derived from structural and quantitative magnetic resonance imaging data.

RESULTS

Transcapillary pulse wave delay was significantly longer in controls compared to AT biomarker-confirmed groups (A+/T-/CN P < .001, A+/T+/CN P < .001, A+/T+/IM P = .003). Intracranial low-frequency oscillations were diminished in AT biomarker-confirmed groups both CN and impaired (A+/T-/CN P = .039, A+/T+/CN P = .007, A+/T+/IM P = .011). A significantly higher presence of microhemorrhages was measured in A+/T+/CN compared to controls (P = .006).

DISCUSSION

Cerebrovascular markers indicate increased vessel stiffness and reduced vasomotion in AT biomarker-positive subjects during preclinical AD.