Depressive Symptoms Have Distinct Relationships With Neuroimaging Biomarkers Across the Alzheimer's Clinical Continuum

Background: Depressive and anxiety symptoms are frequent in Alzheimer’s disease and associated with increased risk of developing Alzheimer’s disease in older adults. We sought to examine their relationships to Alzheimer’s disease biomarkers across the preclinical and clinical stages of the disease. Method: Fifty-six healthy controls, 35 patients with subjective cognitive decline and 56 amyloid-positive cognitively impaired patients on the Alzheimer’s continuum completed depression and anxiety questionnaires, neuropsychological tests and neuroimaging assessments. We performed multiple regressions in each group separately to assess within group associations of depressive and anxiety symptoms with either cognition (global cognition and episodic memory) or neuroimaging data (gray matter volume, glucose metabolism and amyloid load). Results: Depressive symptoms, but not anxiety, were higher in patients with subjective cognitive decline and cognitively impaired patients on the Alzheimer’s continuum compared to healthy controls. Greater depressive symptoms were associated with higher amyloid load in subjective cognitive decline patients, while they were related to higher cognition and glucose metabolism, and to better awareness of cognitive difficulties, in cognitively impaired patients on the Alzheimer’s continuum. In contrast, anxiety symptoms were not associated with brain integrity in any group. Conclusion: These data show that more depressive symptoms are associated with greater Alzheimer’s disease biomarkers in subjective cognitive decline patients, while they reflect better cognitive deficit awareness in cognitively impaired patients on the Alzheimer’s continuum. Our findings highlight the relevance of assessing and treating depressive symptoms in the preclinical stages of Alzheimer’s disease

Critical review of the Appropriate Use Criteria for amyloid imaging: Effect on diagnosis and patient care

INTRODUCTION: The utility of the Appropriate Use Criteria (AUC) for amyloid imaging is not established. METHODS: Fifty-three cognitively impaired patients with clinical F18-florbetapir imaging were classified as early and late onset, as well as AUC-consistent or AUC-inconsistent. Chi-square statistics and t test were used to compare demographic characteristics and clinical outcomes as appropriate. RESULTS: Early-onset patients were more likely to be amyloid positive. Change in diagnosis was more frequent in late-onset cases. Change in therapy was more common in early-onset cases. AUC-consistent and AUC-inconsistent cases had comparable rates of amyloid positivity. We saw no difference in the rate of treatment changes in the AUC-consistent group as opposed to the AUC-inconsistent group. DISCUSSION: The primary role of amyloid imaging in the early-onset group was to confirm the clinically suspected etiology, and in the late-onset group in detecting amyloid-negative cases. The rate of therapeutic changes was significantly greater in the early-onset cases

Cross-sectional and Longitudinal Analysis of the Relationship Between A beta Deposition, Cortical Thickness, and Memory in Cognitively Unimpaired Individuals and in Alzheimer Disease

IMPORTANCE beta-amyloid (A beta) deposition is one of the hallmarks of Alzheimer disease. A beta deposition accelerates gray matter atrophy at early stages of the disease even before objective cognitive impairment is manifested. Identification of at-risk individuals at the presymptomatic stage has become a major research interest because it will allow early therapeutic interventions before irreversible synaptic and neuronal loss occur. We aimed to further characterize the cross-sectional and longitudinal relationship between A beta deposition, gray matter atrophy, and cognitive impairment

Biological brain age prediction using machine learning on structural neuroimaging data: Multi-cohort validation against biomarkers of Alzheimer's disease and neurodegeneration stratified by sex

Brain-age can be inferred from structural neuroimaging and compared to chronological age (brain-age delta) as a marker of biological brain aging. Accelerated aging has been found in neurodegenerative disorders like Alzheimer's disease (AD), but its validation against markers of neurodegeneration and AD is lacking. Here, imaging-derived measures from the UK Biobank dataset (N=22,661) were used to predict brain-age in 2,314 cognitively unimpaired (CU) individuals at higher risk of AD and mild cognitive impaired (MCI) patients from four independent cohorts with available biomarker data: ALFA+, ADNI, EPAD, and OASIS. Brain-age delta was associated with abnormal amyloid-β, more advanced stages (AT) of AD pathology and APOE-ε4 status. Brain-age delta was positively associated with plasma neurofilament light, a marker of neurodegeneration, and sex differences in the brain effects of this marker were found. These results validate brain-age delta as a non-invasive marker of biological brain aging in non-demented individuals with abnormal levels of biomarkers of AD and axonal injury

Whitepaper: Defining and investigating cognitive reserve, brain reserve, and brain maintenance

Several concepts, which in the aggregate get might be used to account for “resilience” against age‐ and disease‐related changes, have been the subject of much research. These include brain reserve, cognitive reserve, and brain maintenance. However, different investigators have use these terms in different ways, and there has never been an attempt to arrive at consensus on the definition of these concepts. Furthermore, there has been confusion regarding the measurement of these constructs and the appropriate ways to apply them to research. Therefore the reserve, resilience, and protective factors professional interest area, established under the auspices of the Alzheimer's Association, established a whitepaper workgroup to develop consensus definitions for cognitive reserve, brain reserve, and brain maintenance. The workgroup also evaluated measures that have been used to implement these concepts in research settings and developed guidelines for research that explores or utilizes these concepts. The workgroup hopes that this whitepaper will form a reference point for researchers in this area and facilitate research by supplying a common language

Perspectives on ethnic and racial disparities in Alzheimer\u27s disease and related dementias: Update and areas of immediate need

Alzheimer\u27s disease and related dementias (ADRDs) are a global crisis facing the aging population and society as a whole. With the numbers of people with ADRDs predicted to rise dramatically across the world, the scientific community can no longer neglect the need for research focusing on ADRDs among underrepresented ethnoracial diverse groups. The Alzheimer\u27s Association International Society to Advance Alzheimer\u27s Research and Treatment (ISTAART; alz.org/ISTAART) comprises a number of professional interest areas (PIAs), each focusing on a major scientific area associated with ADRDs. We leverage the expertise of the existing international cadre of ISTAART scientists and experts to synthesize a cross-PIA white paper that provides both a concise “state-of-the-science” report of ethnoracial factors across PIA foci and updated recommendations to address immediate needs to advance ADRD science across ethnoracial populations. © 2018 The Author

The impact of meditation on healthy ageing - the current state of knowledge and a roadmap to future directions.

peer reviewedThere is increasing evidence that meditation-based training promotes healthy ageing across many dimensions. This review summarizes the existing knowledge on the effects of meditation training on healthy ageing in the domains of emotions, cognition (with a special emphasis on attentional processes), and the preservation of related brain structures. Although evidence so far is promising, more rigorous randomized controlled studies with active control groups and long-term follow-up in older people are needed. We outline how these challenges can be addressed in future studies using the example of an ongoing project, Medit-Ageing (public name: Silver Sante Study), including two independent randomized controlled trials (RCT) as well as one cross-sectional study with meditation experts

Validation de mesures des styles de méditation : Une étude exploratoire chez des méditants non-experts

Construct models of meditation measurements are not fully validated. Several scales exist, however, the assessed underlying cognitive processes are not clearly defined. The objective of our study was to analyse various scales, as well as to propose a rigorous construct of meditation styles based on these scales. Exploratory factor analysis was performed on 131 healthy older participants’ data from the Silver Santé Study. Participants were naïve to meditation practice. Systematic oblimin rotation was used to control the correlation between the following scales: Multidimensional Assessment of Interoceptive Awareness (MAIA), Drexel Defusion Scale, Compassion for Others Scale, Prosocialness Scale and Self-Compassion Scale. According to the Kaiser criterion, the employed factor model culminated in four distinct factors across two axes. Specifically, two mindfulness axes, and two compassion axes. Regarding the two mindfulness axes, we can notice one attention regulation axis which includes items of the MAIA: Noticing, Attention Regulation, Emotional Awareness, Self-Regulation, Body Listening and Trusting. The second axis is focused on cognitive defusion is composed of Drexel Defusion Scale as well as of two items of MAIA Not Distracting and Not Worrying. Concerning the two compassion axes, the first one describes attitudes towards others and is composed of the Compassion for Others and the Prosocialness Scales, while the second axis depicts aspects of being self-centered and includes the Self-Compassion Scale. The factors identified in a population naïve to the meditation practice largely overlap to the theoretical typology distinguishing between attentional (first axis), constructive (third and fourth axes) and deconstructive (second axis) meditation styles.Medit-Agein

Validation of meditation styles measurements: An exploratory study on non expert meditators

De nombreuses échelles évaluant les capacités de méditation existent. Ces échelles recouvrent toutefois de nombreux construits, et les processus cognitifs sous-jacents ne sont pas clairement définis. L'objectif de cette étude est de déterminer si les scores et sous-scores issus de plusieurs échelles se regroupent selon la typologie théorique distinguant différents styles de méditation. Une analyse factorielle exploratoire a été utilisée sur les données de 131 sujets âgés sains ayant participé à l’étude « Silver Santé Study ». Les participants n’étaient pas familiers de la pratique méditative. Une rotation oblimin a été appliquée pour contrôler la présence de corrélations entre les échelles suivantes : Multidimensional Assessment of Interoceptive Awareness (MAIA), Drexel Defusion Scale, Compassion for Others Scale, Prosocialness Scale and Self-Compassion Scale. Selon le critère de Kaiser, le modèle retenu a mis en évidence 4 facteurs se distinguant en 2 axes. Plus spécifiquement, deux axes de pleine conscience et deux axes de compassion. En ce qui concerne les deux axes de pleine conscience, le premier axe concerne la méta-conscience/régulation de l’attention et inclut les items de la MAIA : Noticing, Attention Regulation, Emotional Awareness, Self-Regulation, Body Listening et Trusting. Le deuxième axe se caractérise par la défusion cognitive et est composé du Drexel Defusion Scale ainsi que de deux items de la MAIA: Not Distracting et Not Worrying. Concernant les axes de compassion, le premier décrit les attitudes envers les autres et regroupe les échelles Compassion for Others et Prosocialness, tandis que le second axe se caractérise par des attitudes vis-à-vis de soi et reprend la Self-Compassion Scale. Les facteurs identifiés dans une population non familière de la pratique méditative recoupent largement la typologie théorique en distinguant les axes attentionnel (premier axe), constructif (troisième et quatrième axes) et déconstructif (deuxième axe).Medit-Agein

Olfactory Deficits and Amyloid-beta Burden in Alzheimer's Disease, Mild Cognitive Impairment, and Healthy Aging: A PiB PET Study

Olfactory deficits and increased amyloid-β (Aβ) burden are observed in people with amnestic mild cognitive impairment (aMCI); both factors may be predictive of Alzheimer's disease (AD). We explored whether olfactory identification is related to in vivo measures of Aβ burden using Pittsburgh Compound B (PiB) PET. Nineteen control, 24 aMCI, and 20 AD participants completed an olfactory identification task and underwent PiB PET scanning. Control participants performed better on olfactory identification and showed lower PiB binding than aMCI patients. There was a significant correlation between both factors when pooling all groups together but not when considering each group separately. In addition, the olfactory identification score did not differ between aMCI participants who were PiB-positive and those who were PiB-negative. We conclude that AD-related olfactory identification deficits are not directly related to Aβ burden.7 page(s