Pathologic and cognitive correlates of plasma biomarkers in neurodegenerative disease.

INTRODUCTION: We investigate pathological correlates of plasma phosphorylated tau 181 (p-tau181), glial fibrillary acidic protein (GFAP), and neurofilament light chain (NfL) across a clinically diverse spectrum of neurodegenerative disease, including normal cognition (NormCog) and impaired cognition (ImpCog). METHODS: Participants were NormCog (n = 132) and ImpCog (n = 461), with confirmed ß-amyloid (Aß+/-) status (cerebrospinal fluid, positron emission tomography, autopsy) and single molecule array plasma measurements. Logistic regression and receiver operating characteristic (ROC) area under the curve (AUC) tested how combining plasma analytes discriminated Aß+ from Aß-. Survival analyses tested time to clinical dementia rating (global CDR) progression. RESULTS: Multivariable models (p-tau+GFAP+NfL) had the best performance to detect Aß+ in NormCog (ROCAUC = 0.87) and ImpCog (ROCAUC = 0.87). Survival analyses demonstrated that higher NfL best predicted faster CDR progression for both Aß+ (hazard ratio [HR] = 2.94; p = 8.1e-06) and Aß- individuals (HR = 3.11; p = 2.6e-09). DISCUSSION: Combining plasma biomarkers can optimize detection of Alzheimer's disease (AD) pathology across cognitively normal and clinically diverse neurodegenerative disease. HIGHLIGHTS: Participants were clinically heterogeneous, with autopsy- or biomarker-confirmed Aß. Combining plasma p-tau181, GFAP, and NfL improved diagnostic accuracy for Aß status. Diagnosis by plasma biomarkers is more accurate in amnestic AD than nonamnestic AD. Plasma analytes show independent associations with tau PET and post mortem Aß/tau. Plasma NfL predicted longitudinal cognitive decline in both Aß+ and Aß- individuals.

Determinants of Plasma Alzheimer's Disease Biomarker Use by Primary Care Providers and Dementia Specialists.

BACKGROUND: The efficiencies of plasma Alzheimer's disease (AD) biomarkers could facilitate early AD diagnosis. Unfortunately, limited knowledge exists about whether and how they would be used by clinicians. OBJECTIVE: To identify and compare determinants of plasma AD biomarker use reported by primary care providers and dementia specialists. DESIGN: Semi-structured interviews with clinicians organized using Rogers' Diffusion of Innovations theory and analyzed using an iterative coding approach. PARTICIPANTS: The subjects were internal and family medicine, neurology, and geriatrics providers with varying degrees of expertise in dementia diagnosis and care. MAIN MEASURES: Factors influencing a clinician's decision to use or not use plasma AD biomarkers in clinical practice. KEY RESULTS: We interviewed 30 clinicians (16 family or internal medicine providers, 8 geriatricians, and 6 neurologists). Fifteen were dementia specialists. Hesitance to use plasma AD biomarkers was due to perceived lack of effective treatments for AD, limited access to supports, and stigma. Plasma AD biomarkers would be more readily adopted by clinicians with dementia expertise. CONCLUSIONS: Several factors will influence clinical use of plasma AD biomarkers. Some of them may inform the design of interventions to promote the effective and appropriate clinical translation of these tests.

Development of a Lived Experience Panel to inform the design of embedded pragmatic trials of dementia care interventions.

BACKGROUND: The National Institute on Aging (NIA) Imbedded Pragmatic Alzheimer's Disease and Alzheimer's Related Dementia Clinical Trials (IMPACT) Collaboratory convened a Lived Experience Panel (LEP) to inform the development of research priorities and provide input on conducting embedded pragmatic clinical trials (ePCTs) of dementia care interventions. Given the importance of people with lived experience to dementia research, and the unique considerations of engaging people with dementia, we report on our process for the recruitment, selection, and initial convening of the IMPACT LEP. METHODS: The IMPACT Engaging Partners Team, in partnership with the Alzheimer's Association, sought nominations of individuals with mild cognitive impairment or early-stage dementia, care partners of other people living with dementia (PLWD), and proxy representatives for individuals with mid-to-late stage dementia. The 11-member LEP was composed of individuals with diverse personal experiences in part due to their age, race, ethnicity, gender, sexual orientation, geography, disability, or type of dementia. In its first year, the LEP met with IMPACT's Patient and Caregiver Relevant Outcomes Core and Ethics and Regulation Core. RESULTS: LEP members provided valuable insights and nuanced discussion of issues relevant to ePCTs in dementia care from a broad range of personal experience. Panelists identified key research priorities and provided insight on outcomes often studied by researchers. The LEP also informed investigators' approaches to waivers and modifications of written informed consent and evaluation of minimal risk. Summary reports of the LEP meetings with each Core are available on the IMPACT website. At the end of the first year, changes were made to the composition of the LEP, and opportunities were identified for expanding panelist engagement with IMPACT investigators, as were priorities and scope for future input. CONCLUSIONS: The IMPACT LEP provides a model for engaging PLWD and care partners in the research process as collaborators.

Outcomes with spinal versus general anesthesia for patients with and without preoperative cognitive impairment: Secondary analysis of a randomized clinical trial.

INTRODUCTION: The effect of spinal versus general anesthesia on the risk of postoperative delirium or other outcomes for patients with or without cognitive impairment (including dementia) is unknown. METHODS: Post hoc secondary analysis of a multicenter pragmatic trial comparing spinal versus general anesthesia for adults aged 50 years or older undergoing hip fracture surgery. RESULTS: Among patients randomized to spinal versus general anesthesia, new or worsened delirium occurred in 100/295 (33.9%) versus 107/283 (37.8%; odds ratio [OR] 0.85; 95% confidence interval [CI] 0.60 to 1.19) among persons with cognitive impairment and 70/432 (16.2%) versus 71/445 (16.0%) among persons without cognitive impairment (OR 1.02; 95% CI 0.71 to 1.47, p = 0.46 for interaction). Delirium severity, in-hospital complications, and 60-day functional recovery did not differ by anesthesia type in patients with or without cognitive impairment. DISCUSSION: Anesthesia type is not associated with differences in delirium and functional outcomes among persons with or without cognitive impairment.

Testing for Alzheimer Disease Biomarkers and Disclosing Results Across the Disease Continuum.

Three pathologic processes are characteristic of Alzheimer disease (AD): ß-amyloid, hyperphosphorylated tau, and neurodegeneration. Our understanding of AD is undergoing a transformation due to our ability to measure biomarkers of these processes across different stages of cognitive impairment. There is growing interest in using AD biomarker tests in care and research and, with this, a growing need for guidance on how to return these sensitive results to patients and participants. Here, we propose a 5-step approach informed by clinical and research experience designing and implementing AD biomarker disclosure processes, extant evidence describing how individuals react to AD biomarker information, ethics, law, and the literature on breaking bad news. The clinician should (1) determine the appropriateness of AD biomarker testing and return of results for the particular patient or research participant. If testing is appropriate, the next steps are to (2) provide pretest education and seek consent for testing from the individual and their support person, (3) administer testing, (4) return the results to the individual and their support person, and (5) follow-up to promote the recipient's well-being.

A Roadmap for Modifying Clinician Behavior to Improve the Detection of Cognitive Impairment.

A staggering number of individuals live with cognitive decline. Primary care providers are ideally situated to detect the first signs of cognitive decline, but many persons remain undiagnosed. This limits their access to appropriate care. Unfortunately, the timely diagnosis of mild cognitive impairment or dementia in primary care is difficult to achieve. There is a great need for interventions to address this problem. This article applies an implementation science framework, the Behavioral Change Wheel, to evaluate the factors that influence detection of cognitive impairment in primary care and proposes candidate interventions for future study.