Novel measures of cognition and function for the AD spectrum in the Novel Measures for Alzheimer's Disease Prevention Trials (NoMAD) project: Psychometric properties, convergent validation, and contrasts with established measures.

INTRODUCTION: This study derived composite scores for two novel cognitive measures, the No Practice Effect (NPE) battery and the Miami Computerized Functional Skills Assessment and Training system for use in early-stage Alzheimer's disease (AD) clinical trials. Their psychometric properties and associations with AD risk markers were compared to those of well-established measures. METHODS: For 291 older adults with healthy cognition or early mild cognitive impairment, Exploratory factor analyses were used to identify the factor structure of the NPE. Factor and total scores were examined for their psychometric properties and associations with AD risk biomarkers. RESULTS: Composite scores from the novel cognitive and functional measures demonstrated better psychometric properties (distribution and test-retest reliability) and stronger associations with AD-related demographic, genetic, and brain risk markers than well-established measures, DISCUSSION: These novel measures have potential for use as primary cognitive and functional outcomes in early-stage AD clinical trials. HIGHLIGHTS: Well-established cognitive tests may not accurately detect subtle cognitive changes. No Practice Effect (NPE) and Computerized Functional Skills Assessment and Training are novel measures designed to have improved psychometric properties. NPE had Executive Function, Cognitive Control/Speed, and Episodic Memory domains. Novel measures had better psychometric properties compared to established measures. Significant associations with Alzheimer's disease biomarkers were found with novel measures.

Characterizing Neighborhood Vulnerabilities in Mild Cognitive Impairment using the Environmental Justice Index.

Background: There is a need for integration and comprehensive characterization of environmental determinants of Alzheimer's disease. The Environmental Justice Index (EJI) is a new measure that consolidates multiple environmental health hazards. Objective: This analysis aims to explore how environmental vulnerabilities vary by race/ethnicity and whether they predict cognitive outcomes in a clinical trial of mild cognitive impairment (MCI). Methods: We used data from a clinical trial of 107 MCI participants (28% minorities). Using the EJI, we extracted 40 measures of neighborhood environmental and social vulnerability including air and water pollution, access to recreational spaces, exposure to coal and lead mines, and area poverty. We also examined the relationship of the EJI to the Area Deprivation Index (ADI). Data was analyzed using regressions, correlations, and t-tests. Results: Environmental Burden Rank (EBR) across the sample (0.53±0.32) was near the 50th percentile nationally. When divided by race/ethnicity, environmental (p = 0.025) and social (p < 0.0001) vulnerabilities were significantly elevated for minorities, specifically for exposure to ozone, diesel particulate matter, carcinogenic air toxins, and proximity to treatment storage and disposal sites. ADI state decile was not correlated with the EBR. Neither EBR nor ADI were a significant predictor of cognitive decline. Conclusions: To our knowledge, this is the first study to link the EJI to an MCI trial. Despite limitations of a relatively small sample size, the study illustrates the potential of the EJI to provide deeper phenotyping of the exposome and diversity in clinical trial subjects.

Sleep-wake behavior, perceived fatigability, and cognitive reserve in older adults.

INTRODUCTION: The effects of sleep-wake behavior on perceived fatigability and cognitive abilities when performing daily activities have not been investigated across levels of cognitive reserve (CR). METHODS: CR Index Questionnaire (CRIq) data were collected and subjected to moderated mediation analysis. RESULTS: In amnestic mild cognitive impairment (aMCI; n = 41), CR moderated sleep-related impairments (SRIs), and fatigability at low CR (CRIq < 105.8, p = 0.004) and mean CR (CRIq = 126.9, p = 0.03) but not high CR (CRIq > 145.9, p = 0.65) levels. SRI affected cognitive abilities mediated by fatigability at low CR (p < 0.001) and mean CR (p = 0.003) levels. In healthy controls (n = 13), SRI in fatigability did not alter cognitive abilities across CR levels; controls had higher leisure scores than patients with aMCI (p = 0.003, effect size = 0.93). DISCUSSION: SRI can amplify impaired cognitive abilities through exacerbation of fatigability in patients with aMCI with below-mean CR. Therefore, improving sleep-wake regulation and leisure activities may protect against fatigability and cognitive decline. HIGHLIGHTS: Clinical fatigue and fatigability cannot be alleviated by rest. Clinical fatigability disrupts daily activities during preclinical Alzheimer's. High cognitive reserve mitigates sleep-wake disturbance effects. High cognitive reserve attenuates clinical fatigability effects on daily functioning. Untreated obstructive sleep apnea potentiates Alzheimer's pathology in the brain.

Association Between Multisensory Impairment and Depression Among Older Adults: A Population-Based Analysis.

OBJECTIVE: In this study, we examine how impairments in vision, hearing, touch, and olfaction relate to depression in older adults, considering both individual and multisensory impairments (MSIs). STUDY DESIGN: Analysis of cross-sectional data from a longitudinal investigation involving black and white older adults aged 70 to 79 at enrollment. SETTING: We studied 1640 black and white participants in the Health ABC study using complete sensory evaluation data from years 3 to 5. METHODS: Our MSI assessment utilized data obtained for visual acuity, hearing perception, olfactory performance, and tactile function. We performed multivariable logistic regression analyses to examine the associations between the presence of individual and MSIs and depression which was defined as the presence of antidepressants prescribed for depression, or a Center for Epidemiological Studies Depression Scale score of greater than 10. RESULTS: We observed a possible dose-response relationship between the number of sensory impairments and depression. In adjusted models, when compared to no impairments, vision (odds ratio [OR] = 1.45, 95% confidence interval [CI]: 1.09-1.93) and hearing impairments (OR = 1.49, 95% CI: 1.11-1.99) were significantly associated with depression, whereas olfaction (OR = 1.11, 95% CI: 0.83-1.47) and tactile impairments (OR = 1.28, 95% CI: 0.96-1.70) were not. Participants with 3 sensory impairments had a higher rate of depression (OR = 2.05, 95% CI: 1.22-3.54) compared to those without impairments, and this risk increased further for those with 4 sensory impairments (OR = 2.95, 95% CI: 1.48-5.88). CONCLUSION: The findings suggest that individuals with MSI represent a high-risk population for depression, warranting close monitoring to screen for depression. The study emphasizes the importance of considering multiple sensory impairments in the context of mental health and supports the early identification and monitoring of depression in this population.

Remote Associations Between Tau and Cortical Amyloid-ß Are Stage-Dependent.

Background: Histopathologic studies of Alzheimer's disease (AD) suggest that extracellular amyloid-ß (Aß) plaques promote the spread of neurofibrillary tau tangles. However, these two proteinopathies initiate in spatially distinct brain regions, so how they interact during AD progression is unclear. Objective: In this study, we utilized Aß and tau positron emission tomography (PET) scans from 572 older subjects (476 healthy controls (HC), 14 with mild cognitive impairment (MCI), 82 with mild AD), at varying stages of the disease, to investigate to what degree tau is associated with cortical Aß deposition. Methods: Using multiple linear regression models and a pseudo-longitudinal ordering technique, we investigated remote tau-Aß associations in four pathologic phases of AD progression based on tau spread: 1) no-tau, 2) pre-acceleration, 3) acceleration, and 4) post-acceleration. Results: No significant tau-Aß association was detected in the no-tau phase. In the pre-acceleration phase, the earliest stage of tau deposition, associations emerged between regional tau in medial temporal lobe (MTL) (i.e., entorhinal cortex, parahippocampal gyrus) and cortical Aß in lateral temporal lobe regions. The strongest tau-Aß associations were found in the acceleration phase, in which tau in MTL regions was strongly associated with cortical Aß (i.e., temporal and frontal lobes regions). Strikingly, in the post-acceleration phase, including 96% of symptomatic subjects, tau-Aß associations were no longer significant. Conclusions: The results indicate that associations between tau and Aß are stage-dependent, which could have important implications for understanding the interplay between these two proteinopathies during the progressive stages of AD.