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See Derry and Kent (doi:10.1093/awx167) for a scientific commentary on this article.The large variance in cognitive deterioration in subjects who test positive for amyloid-β by positron emission tomography indicates that convergent pathologies, such as iron accumulation, might combine with amyloid-β to accelerate Alzheimer's disease progression. Here, we applied quantitative susceptibility mapping, a relatively new magnetic resonance imaging method sensitive to tissue iron, to assess the relationship between iron, amyloid-β load, and cognitive decline in 117 subjects who underwent baseline magnetic resonance imaging and amyloid-β positron emission tomography from the Australian Imaging, Biomarkers and Lifestyle study (AIBL). Cognitive function data were collected every 18 months for up to 6 years from 100 volunteers who were either cognitively normal (n = 64) or diagnosed with mild cognitive impairment (n = 17) or Alzheimer's disease (n = 19). Among participants with amyloid pathology (n = 45), higher hippocampal quantitative susceptibility mapping levels predicted accelerated deterioration in composite cognition tests for episodic memory [β(standard error) = -0.169 (0.034), P = 9.2 × 10-7], executive function [β(standard error) = -0.139 (0.048), P = 0.004), and attention [β(standard error) = -0.074 (0.029), P = 0.012]. Deteriorating performance in a composite of language tests was predicted by higher quantitative susceptibility mapping levels in temporal lobe [β(standard error) = -0.104 (0.05), P = 0.036] and frontal lobe [β(standard error) = -0.154 (0.055), P = 0.006]. These findings indicate that brain iron might combine with amyloid-β to accelerate clinical progression and that quantitative susceptibility mapping could be used in combination with amyloid-β positron emission tomography to stratify individuals at risk of decline., (© The Author (2017). Published by Oxford University Press on behalf of the Guarantors of Brain. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Introduction: High levels of amyloid β (Aβ) are associated with cognitive decline in cognitively normal (CN) older adults. This study investigated the nature of cognitive decline in healthy individuals who did not progress to mild cognitive impairment or dementia., Method: Cognition was measured over 72 months and compared between low (Aβ-) and high (Aβ+) CN older adults ( n  = 335) who did not progress to mild cognitive impairment or dementia and who remained free of severe or uncontrolled systemic illness., Results: Compared to the Aβ- group, the Aβ+ group showed no cognitive impairment at baseline but showed substantial decline in verbal learning, episodic memory, and attention over 72 months., Discussion: Moderate cognitive decline, particularly for learning and memory, was associated with Aβ+ in CN older adults in the absence of clinical disease progression and uncontrolled or serious comorbid illness.

Introduction: The diagnostic utility of in vivo amyloid β (Aβ) imaging to aid in the clinical distinction between frontotemporal dementia (FTD) and Alzheimer's disease remains unclear without data on the prevalence and severity of Aβ in pathologically confirmed FTD syndromes., Methods: Aβ was assessed in 98 autopsy-confirmed FTD and 36 control cases, and the pathological accuracy of 11 C-Pittsburgh compound B (PiB)-positron emission tomography imaging was assessed in a subset of FTD cases ( n  = 15)., Results: Aβ was identified in a similar proportion of FTD syndromes and age-matched controls and increases with age. Alzheimer's disease pathology was identified in all cases with high PiB retention and in one case with low PiB retention. We further demonstrate a strong regional correlation between volume fraction of histological Aβ with PiB standard uptake value ratio scaled to the white matter., Discussion: The present study provides a pathologic reference to assist in the interpretation of in vivo assessments in FTD syndromes.

We fractionated frontal cortical grey matter from human Alzheimer's disease and control subjects into four biochemically defined pools that represent four distinct compartments: soluble/cytosolic, peripheral membrane/vesicular cargo, integral lipid/membranous pools and aggregated/insoluble debris. Most of the readily extractable amyloid-β remains associated with a lipid/membranous compartment. There is an exchange of amyloid-β between the biochemical pools that was lost for the amyloid-β42 species in Alzheimer's disease, consistent with the peptide being irreversibly trapped in extracellular deposits. The quantitative amyloid-β data, combined with magnetic resonance imaging volumetric analysis of the amount of cortical grey matter in brain, allowed us to estimate the total mass of amyloid-β in Alzheimer's disease (6.5 mg) and control (1.7 mg) brains. The threshold positron emission tomography standard uptake value ratio of 1.4 equates to 5.0 μg amyloid-β/g of grey matter and the mean Alzheimer's disease dementia standard uptake value ratio level of 2.3 equates to 11.20 μg amyloid-β/g of grey matter. It takes 19 years to accumulate amyloid from the threshold positron emission tomography standard uptake value ratio to the mean value observed for Alzheimer's disease dementia. This accumulation time window combined with the difference of 4.8 mg of amyloid-β between Alzheimer's disease and control brain allows for a first approximation of amyloid-β accumulation of 28 ng/h. This equates to an estimated 2-5% of the total amyloid-β production being deposited as insoluble plaques. Understanding these rates of amyloid-β accumulation allows for a more quantitative approach in targeting the failure of amyloid-β clearance in sporadic Alzheimer's disease., (© The Author (2017). Published by Oxford University Press on behalf of the Guarantors of Brain. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Introduction: A blood-based biomarker panel to identify individuals with preclinical Alzheimer's disease (AD) would be an inexpensive and accessible first step for routine testing., Methods: We analyzed 14 biomarkers that have previously been linked to AD in the Australian Imaging Biomarkers lifestyle longitudinal study of aging cohort., Results: Levels of apolipoprotein J (apoJ) were higher in AD individuals compared with healthy controls at baseline and 18 months ( P = .0003) and chemokine-309 (I-309) were increased in AD patients compared to mild cognitive impaired individuals over 36 months ( P = .0008)., Discussion: These data suggest that apoJ may have potential in the context of use (COU) of AD diagnostics, I-309 may be specifically useful in the COU of identifying individuals at greatest risk for progressing toward AD. This work takes an initial step toward identifying blood biomarkers with potential use in the diagnosis and prognosis of AD and should be validated across other prospective cohorts.

Introduction: "Walkable" neighborhoods offer older adults opportunities for activities that may benefit cognition-related biological mechanisms. These have not previously been examined in this context., Methods: We objectively assessed neighborhood walkability for participants (n = 146) from the Australian Imaging, Biomarkers and Lifestyle study with apolipoprotein E (APOE) genotype and two 18-month-apart brain volumetric and/or amyloid β burden assessments. Linear mixed models estimated associations of neighborhood walkability with levels and changes in brain imaging outcomes, the moderating effect of APOE ε4 status, and the extent to which associations were explained by physical activity., Results: Cross-sectionally, neighborhood walkability was predictive of better neuroimaging outcomes except for left hippocampal volume. These associations were to a small extent explained by physical activity. APOE ε4 carriers showed slower worsening of outcomes if living in walkable neighborhoods., Discussion: These findings indicate associations between neighborhood walkability and brain imaging measures (especially in APOE ε4 carriers) minimally attributable to physical activity., (Copyright © 2016 the Alzheimer's Association. Published by Elsevier Inc. All rights reserved.)

Objective: Several studies have reported that non-demented older adults with clinical depression show changes in amyloid-β (Aβ) levels in blood, cerebrospinal fluid and on neuroimaging that are consistent with those observed in patients with Alzheimer's disease. These findings suggest that Aβ may be one of the mechanisms underlying the relation between the two conditions. We sought to determine the relation between elevated cerebral Aβ and the presence of depression across a 54-month prospective observation period., Methods: Cognitively normal older adults from the Australian Imaging Biomarkers and Lifestyle study who were not depressed and had undergone a positron emission tomography scan to classify them as either high Aβ (n = 81) or low Aβ (n = 278) participated. Depressive symptoms were assessed using the Geriatric Depression Scale - Short Form at 18-month intervals over 54 months., Results: Whilst there was no difference in probable depression between groups at baseline, incidence was 4.5 (95% confidence interval [CI] 1.3-16.4) times greater within the high Aβ group (9%) than the low Aβ group (2%) by the 54-month assessment., Conclusions: Results of this study suggest that elevated Aβ levels are associated with a 4.5-fold increased likelihood of developing clinically significant depressive symptoms on follow-up in preclinical Alzheimer's disease. This underscores the importance of assessing, monitoring and treating depressive symptoms in older adults with elevated Aβ. Copyright © 2016 John Wiley & Sons, Ltd., (Copyright © 2016 John Wiley & Sons, Ltd.)

Subjective memory decline (SMD) is a heterogeneous condition. While SMD might be the earliest sign of Alzheimer's disease (AD), it also occurs in aging and various neurological, medical, and psychiatric conditions. Identifying those with higher risk to develop dementia is thus a major challenge. We tested a novel disease severity index generated by multivariate data analysis with numerous structural MRI measures as input. The index was used to identify SMD individuals with high risk of progression to mild cognitive impairment (MCI) or AD. A total of 69 healthy controls, 86 SMD, 45 MCI, and 38 AD patients were included. Subjects were followed up for 7.5 years. Clinical, cognitive, PET amyloid imaging and APOE ε4 data were used as outcome variables. The results showed that SMD evidenced cognitive performance intermediate between healthy controls and MCI. The disease severity index identified eleven (13%) SMD individuals with an AD-like pattern of brain atrophy. These individuals showed lower cognitive performance, increased CDR-SOB, higher amyloid burden and worse clinical progression (6.2 times higher likelihood to develop MCI, dementia or die than healthy controls). The current disease severity index may have relevance for clinical practice, as well as for selecting appropriate individuals for clinical trials.

Background: Rhinoconjunctivitis-specific quality of life is often reduced during seasonal allergies. The Mini Rhinoconjunctivitis Quality of Life Questionnaire (MRQLQ) is a validated tool used to measure quality of life in people experiencing allergies (0 = not troubled to 6 = extremely troubled). Probiotics may improve quality of life during allergy season by increasing the percentage of regulatory T cells (Tregs) and inducing tolerance. Objective: The objective of this study was to determine whether consuming Lactobacillus gasseri KS-13, Bifidobacterium bifidum G9-1, and B. longum MM-2 compared with placebo would result in beneficial effects on MRQLQ scores throughout allergy season in individuals who typically experience seasonal allergies. Secondary outcomes included changes in immune markers as part of a potential mechanism for changes in MRQLQ scores. Design: In this double-blind, placebo-controlled, parallel, randomized clinical trial, 173 participants (mean ± SEM: age 27 ± 1 y) who self-identified as having seasonal allergies received either a probiotic (2 capsules/d, 1.5 billion colony-forming units/capsule) or placebo during spring allergy season for 8 wk. MRQLQ scores were collected weekly throughout the study. Fasting blood samples were taken from a subgroup (placebo, n = 37; probiotic, n = 35) at baseline and week 6 (predicted peak of pollen) to determine serum immunoglobulin (Ig) E concentrations and Treg percentages. Results: The probiotic group reported an improvement in the MRQLQ global score from baseline to pollen peak (-0.68 ± 0.13) when compared with the placebo group (-0.19 ± 0.14; P = 0.0092). Both serum total IgE and the percentage of Tregs increased from baseline to week 6, but changes were not different between groups. Conclusions: This combination probiotic improved rhinoconjunctivitis-specific quality of life during allergy season for healthy individuals with self-reported seasonal allergies; however, the associated mechanism is still unclear. This trial was registered at clinicaltrials.gov as NCT02349711., (© 2017 American Society for Nutrition.)

Background: We report results of the novel Washout Allometric Reference Method (WARM) that uses estimates of cerebral blood flow and amyloid load from the same [ 11 C]Pittsburgh Compound B ([ 11 C]PiB) retention maps in brain to distinguish between patients with different forms dementia, including Alzheimer's disease, and healthy volunteers. The method introduces two approaches to the identification of brain pathology related to amyloid accumulation, (1) a novel analysis of amyloid binding based on the late washout of the tracer from brain tissue, and (2) the simultaneous estimation of absolute cerebral blood flow indices (sCBF) from the early accumulation of the tracer in brain tissue. Objective: We tested the hypothesis that a change of cerebral blood flow is correlated with the degree of tracer [ 11 C]PiB retention, reflecting dendritic spine pathology and consequent inhibition of brain energy metabolism and reduction of blood flow by neurovascular coupling in neurodegenerative disorders, including Alzheimer's disease. Methods: Previously reported images of [ 11 C]PiB retention in brain of 29 subjects with cognitive impairment or dementia [16 Alzheimer's Disease (AD), eight subjects with dementia with Lewy bodies (DLB), five patients with frontotemporal lobar degeneration (FTLD), five patients with mild cognitive impairment, and 29 age-matched healthy control subjects (HC)], underwent analysis of PiB delivery and retention by means of WARM for quantitation of [ 11 C]PiB's binding potentials ( BP ND ) and correlated surrogate cerebral blood flow (sCBF) estimates, based on the [ 11 C]PiB images, compared to estimates by conventional Standard Uptake Value Ratio (SUVR) of [ 11 C]PiB retention with cerebellum gray matter as reference. Receiver Operating Characteristics (ROC) revealed the power of discrimination among estimates. Results: For AD, the discriminatory power of [ 11 C]PiB binding potential ( BP ND ) by WARM exceeded the power of SUVR that in turn exceeded the power of sCBF estimates. Differences of [ 11 C]PiB binding and sCBF measures between AD and HC both were highly significant ( p < 0.001). For all the dementia groups as a whole, sCBF estimates revealed the greatest discrimination between the patient and HC groups. WARM resolves a major issue of amyloid load quantification with [ 11 C]PiB in human brain by determining absolute sCBF and amyloid load measures from the same images. The two parameter approach provides key discriminary information in AD for which [ 11 C]PiB traditionally is used, as well as for the distinct flow deficits in FTLD, and the marked parietal and occipital lobe flow deficits in DLB. Conclusion: We conclude that WARM yields estimates of two important variables that together discriminate among patients with dementia, including AD, and healthy volunteers, with ROC that are superior to conventional methods of analysis. The distinction between estimates of flow and amyloid load from the same dynamic emission tomograms provides valuable pathogenetic information.

The introduction of in vivo imaging of Aβ-amyloid (Αβ) pathology more than a decade ago, transformed the assessment of Alzheimer disease (AD) allowing the evaluation of Aβ deposition over time by providing highly accurate, reliable, and reproducible quantitative statements of regional or global Aβ burden in the brain to the extent that Aβ imaging has already been approved for clinical use and is being used for both patient recruitment and outcome measure in current anti-Αβ therapeutic trials. Aβ imaging studies have deepened our insight into Aβ deposition, showing that Aβ accumulation is a slow and protracted process extending for more than two decades before the onset of the clinical phenotype. Although cross-sectional evaluation of Αβ burden does not strongly correlate with cognitive impairment in AD, Αβ burden does correlate with memory impairment and a higher risk for cognitive decline in the aging population and mild cognitive impairment subjects. These associations suggest that Αβ deposition is not a benign process. The recent addition of selective tau imaging will allow to elucidate if these effects are directly associated with Αβ deposition or if they are mediated, in toto or in parte, by tau as it spreads out of the mesial temporal lobe into neocortical association areas. The combination of Aβ and tau imaging studies would likely help elucidate the relationship or interplay between the two pathologic hallmarks of the disease. Longitudinal observations to assess their potential independent or synergistic, sequential or parallel effects on cognition, disease progression, and other disease-specific biomarkers of neurodegeneration would be required to further clarify the respective role of Αβ and tau deposition play in the course of AD., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Evidence suggests that a diet low in carbohydrates can impact on cognitive performance among those with Alzheimer's disease (AD). However, there is a lack of data assessing this relationship among cognitively normal (CN) older adults at increased future risk of developing AD due to carriage of the apolipoprotein E (APOE) ɛ4 allele. We assessed the cross-sectional association between carbohydrate intake, cognitive performance, and cerebral amyloid-β (Aβ) load in CN older adults, genotyped for APOEɛ4 allele carrier status. Greater carbohydrate intake was associated with poorer performance in verbal memory in APOEɛ4 allele non-carriers, and poorer performance in attention in APOEɛ4 allele carriers. There were no associations between carbohydrate intake and cerebral Aβ load. These results provide support to the idea that decreasing carbohydrate intake may offer neurocognitive benefits, with specific cognitive domains affected in an APOE genotype-dependent manner. These findings warrant further investigation utilizing a longitudinal study design.

Background: In cognitively normal (CN) older adults, carriage of the apolipoprotein E (APOE) ɛ4 allele is associated with increased risk for dementia of the Alzheimer type (AD-dementia). It is unclear whether this occurs solely through APOEɛ4 increasing amyloid-β (Aβ) accumulation or through processes independent of Aβ., Objective: To determine the extent and nature to which APOEɛ4 increases risk for clinical disease progression in CN older adults., Methods: Data from the total (n = 765) and Aβ-imaged (n = 423) CN cohort in the Australian Imaging, Biomarker and Lifestyle (AIBL) Study of Ageing was analyzed using Cox proportional hazard models to estimate ɛ4 risk for clinical disease progression over a 72-month follow-up., Results: With Aβ status unknown and risk from demographic characteristics controlled, ɛ4 carriage increased risk for clinical disease progression over 72 months by 2.66 times compared to risk of non-ɛ4 carriage. Re-analysis with Aβ status included showed that abnormally high Aβ increased risk for clinical disease progression over 72 months by 2.11 times compared to risk of low Aβ. However, with Aβ level known, ɛ4 carriage was no longer predictive of clinical disease progression., Conclusion: In CN older adults, the risk of ɛ4 for clinical disease progression occurs through the effect of ɛ4 increasing Aβ levels.

Cortical cholinergic deficiency is prominent in Alzheimer's disease (AD), and published findings of diminished pupil flash response in AD suggest that this deficiency may extend to the visual cortical areas and anterior eye. Pupillometry is a low-cost, noninvasive technique that may be useful for monitoring cholinergic deficits which generally lead to memory and cognitive disorders. The aim of the study was to evaluate pupillometry for early detection of AD by comparing the pupil flash response (PFR) in AD ( N = 14) and cognitively normal healthy control (HC, N = 115) participants, with the HC group stratified according to high ( N = 38) and low ( N = 77) neocortical amyloid burden (NAB). Constriction phase PFR parameters were significantly reduced in AD compared to HC (maximum acceleration p < 0.05, maximum velocity p < 0.0005, average velocity p < 0.005, and constriction amplitude p < 0.00005). The high-NAB HC subgroup had reduced PFR response cross-sectionally, and also a greater decline longitudinally, compared to the low-NAB subgroup, suggesting changes to pupil response in preclinical AD. The results suggest that PFR changes may occur in the preclinical phase of AD. Hence, pupillometry has a potential as an adjunct for noninvasive, cost-effective screening for preclinical AD.

Background: Hypothalamic-pituitary-adrenal axis dysregulation, which is typically assessed by measuring cortisol levels, is associated with cognitive dysfunction, hippocampal atrophy, and increased risk for mild cognitive impairment and Alzheimer's disease (AD). However, little is known about the role of hypothalamic-pituitary-adrenal axis dysregulation in moderating the effect of high levels of amyloid-β (Aβ+) on cognitive decline in the preclinical phase of AD, which is often protracted, and thus offers opportunities for prevention and early intervention., Methods: Using data from a 6-year multicenter prospective cohort study, we evaluated the relation between Aβ level, plasma cortisol level, and cognitive decline in 416 cognitively normal older adults., Results: Results revealed that Aβ+ older adults experienced faster decline than Aβ- older adults in all cognitive domains (Cohen's d at 6-year assessment = 0.37-0.65). They further indicated a significant interaction between Aβ and cortisol levels for global cognition (d = 0.32), episodic memory (d = 0.50), and executive function (d = 0.59) scores, with Aβ+ older adults with high cortisol levels having significantly faster decline in these domains compared with Aβ+ older adults with low cortisol levels. These effects were independent of age, sex, APOE genotype, anxiety symptoms, and radiotracer type., Conclusions: In cognitively healthy older adults, Aβ+ is associated with greater cognitive decline and high plasma cortisol levels may accelerate the effect of Aβ+ on decline in global cognition, episodic memory, and executive function. These results suggest that therapies targeted toward lowering plasma cortisol and Aβ levels may be helpful in mitigating cognitive decline in the preclinical phase of AD., (Published by Elsevier Inc.)

Background: The association between the apolipoprotein E (APOE) ɛ4 allele and high risk of developing Alzheimer's disease (AD) dementia before the age of 80 has been recognized for over 30 years. However, the timing and mode of action of APOE is not understood, nor has there been a detailed analysis of the effect of APOE genotype on memory, hippocampal volume, and amyloid-β (Aβ) levels in cognitively normal adults., Objective: Examine the effect of APOE allelic genotype on the relationship between Aβ levels, hippocampal volume, and memory in cognitively normal adults., Methods: This is a cross-sectional study of 989 cognitively normal older adults enrolled in the Australian Imaging, Biomarkers and Lifestyle (AIBL) study, all of whom underwent APOE genotyping and memory assessment. A subset of this group underwent PET neuroimaging for Aβ (n = 585) and MRI for hippocampal volume (n = 303)., Results: APOEɛ4 homozygotes (ɛ4/ɛ4) showed significantly worse episodic memory and higher Aβ levels than ɛ4 heterozygotes. The relationship between increasing Aβ levels and worse episodic memory was significant for ɛ3 homozygotes (ɛ3/ɛ3), ɛ4 heterozygotes, and strongest for ɛ4 homozygotes. There were no differences in hippocampal volume between APOE groups; the relationship between smaller hippocampal volume and worse episodic memory was significant only for ɛ4 homozygotes., Conclusion: APOE acts in a co-dominant fashion on Aβ levels, episodic memory, and hippocampal volume in cognitively normal older adults. APOEɛ4 is central to the events that lead to AD in cognitively normal older adults, likely through a quantitative role in the disruption of Aβ clearance.

Of 57 individuals diagnosed with Alzheimer's disease (AD) in a phase III study, 13 (23%) had amyloid-β (Aβ) levels on postmortem histopathology that did not explain the dementia. Based on postmortem histopathology, a wide range of different non-AD conditions was identified, including frontotemporal dementia, hippocampal sclerosis, and dementia with Lewy bodies. Of the histopathologically Aβ negative scored cases ante-mortem Florbetaben PET scans were classified as negative for Aβ in 11 patients based on visual analysis and in all 12 quantifiable cases based on composite standardized uptake value ratios. Thus, florbetaben PET can assist physicians in the differential diagnosis of neurodegenerative disorders by reliably excluding Aβ pathology.

Background and Purpose: Visualization of pathogenic protein aggregates is crucial to elucidate pathomechanisms and to make an accurate diagnosis in many neurodegenerative conditions. Aggregates of the microtubule-binding protein, tau, are one of the most important pathogenic molecules in neurodegenerative disorders. Progressive supranuclear palsy (PSP) is characterized by the deposition of tau proteins in some specific area such as the basal ganglia and brainstem. We tried to detect tau lesions in the brains of living patients with PSP with a novel positron emission tomography (PET) tracer, [ 18 F]THK-5351, which we have recently developed., Methods: Paraffin-embedded brain sections of the patients with PSP were used for autoradiography with [ 3 H]THK-5351 and immunohistochemistry. Nine healthy controls, 13 patients with Alzheimer's disease and three patients with PSP participated in this PET study with [ 18 F]THK-5351. To detect amyloid-β deposition, PET imaging with Pittsburgh compound B was also performed., Results: Autoradiography in the brain sections of patients with PSP demonstrated [ 3 H]THK-5351 binding to tau deposits with a high selectivity. Although patients with PSP exhibited no remarkable [ 18 F]THK-5351 retention in the temporal cortex, significantly higher tracer retention was observed in the globus pallidus and midbrain. In contrast, amyloid imaging with Pittsburgh compound B showed no remarkable accumulation in the cerebral cortex of PSP., Conclusions: We conclude that [ 18 F]THK-5351 PET can potentially be used to detect the regional brain distribution of tau lesions in PSP, thereby facilitating the differential diagnosis of neurodegenerative disorders associated with tau protein., (© 2016 EAN.)

Objective: To examine how β-amyloid (Aβ), APOE and BDNF genotypes, and cortisol relate to depressive and anxiety symptoms in cognitively normal older women and men., Methods: Cross-sectional data were analyzed from 423 older adults from the Australian Imaging Biomarkers and Lifestyle study. Analyses of covariance evaluated associations between Aβ, APOE and BDNF genotype, and cortisol in relation to severity of depressive and anxiety symptoms., Results: Among Aβ+ older adults, APOE ε4 carriage was associated with greater severity of anxiety symptoms (d = 0.55); and in the full sample, APOE ε4 carriage was linked to greater severity of depressive (d = 0.26) and anxiety (d = 0.21) symptoms. Among Aβ+ women, ε4 carriers reported greater anxiety symptoms than non-ε4 carriers (d = 0.83), and female BDNF rs6265 Val66 Met allele carriers reported greater depressive symptoms (d = 0.29)., Conclusion: Sex moderated the relationship between Aβ, APOE genotype, and BDNF genotype in predicting severity of anxiety and depressive symptoms in cognitively normal older adults., (Copyright © 2016 American Association for Geriatric Psychiatry. All rights reserved.)

In a group of older adults with very mild dementia, we aimed to characterize the nature and magnitude of cognitive decline as measured by the Cogstate Brief Battery, in relation to Aβ levels and hippocampal volume. Participants were characterized according to their status on the Clinical Dementia Rating (CDR) scale. A total of 308 individuals who were CDR 0 and had low cerebral Aβ levels (Aβ-), 32 individuals who were Aβ- and CDR 0.5, and 43 individuals who were Aβ+ and CDR 0.5 were included in this study. Participants completed the CogState brief battery at baseline, and at 18-, 36-, 54- and 72-month follow-up. Linear mixed model analyses indicated that relative to the Aβ- CDR 0 group, the Aβ+ CDR 0.5 group showed increased rates of memory decline and hippocampal volume loss. However, compared to the Aβ- CDR 0 group, the Aβ- CDR 0.5 group showed no changes in cognitive function or hippocampal volume over 72 months. The results of this study confirm that in individuals with very mild dementia, who also have biomarker confirmation of Aβ+, changes in cognitive function manifest primarily as deterioration in memory processing, and this is associated with hippocampal volume loss. Conversely, the absence of any cognitive decline or loss in hippocampal volume in individuals with very mild dementia but who are Aβ- suggests that some other non-AD disease process may underlie any static impairment in cognitive function.

This commentary outlines a conceptual model for subjective cognitive decline (SCD) in relation to Alzheimer's disease (AD) biomarkers in the preclinical stages of disease and a framework for effectively utilizing SCD in secondary prevention clinical trials. Mounting evidence supports the notion that SCD is sensitive to encroaching Aβ-amyloid and neurodegeneration. SCD has also been shown to provide additive information of AD-dementia risk beyond what is known about the biomarker status of the individual. Thus, we provide recommendations for the implementing SCD measurement in clinical trials. We argue that SCD can be measured at three catch points within the course of the clinical trial: firstly, at the initial recruitment and screening phase; secondly, to create more robust estimates of rates of AD-dementia progression; and finally, to measure subjective experiences of cognitive change and quality of life over the course of the trial as a proxy of clinically meaningful functional improvement. We provide recommendations of how SCD can be approached at each of these points. SCD is an important component of the preclinical AD-dementia trajectory. Future studies need to elucidate the interactive influence of Aβ-amyloid and tau on SCD from a spatiotemporal perspective. Even as this evidence accrues, it is clear that SCD can provide unique and additive information about rates of progression and subjectively experienced cognitive change within clinical trials.

Objective: We assessed a blood-based signature, which previously demonstrated high accuracy at stratifying individuals with high or low neocortical β-amyloid burden (NAB), to determine whether it could also identify individuals at risk of progression to Alzheimer disease (AD) within 54 months., Methods: We generated the blood-based signature for 585 healthy controls (HCs) and 74 participants with mild cognitive impairment (MCI) from the Australian Imaging, Biomarkers and Lifestyle Study who underwent clinical reclassification (blinded to biomarker findings) at 54-month follow-up. The individuals were split into estimated high and low NAB groups based on a cutoff of 1.5 standardized uptake value ratio. We assessed the predictive accuracy of the high and low NAB groupings based on progression to mild cognitive impairment or AD according to clinical reclassification at 54-month follow-up., Results: Twelve percent of HCs with estimated high NAB progressed in comparison to 5% of HCs with estimated low NAB (odds ratio = 2.4). Forty percent of the participants with MCI who had estimated high NAB progressed in comparison to 5% of the participants with MCI who had estimated low NAB (odds ratio = 12.3). These ratios are in line with those reported for Pittsburgh compound B-PET results. Individuals with estimated high NAB had faster rates of memory decline than those with estimated low NAB., Conclusion: These findings suggest that a simple blood-based signature not only provides estimates of NAB but also predicts cognitive decline and disease progression, identifying individuals at risk of progressing toward AD at the prodromal and preclinical stages., (© 2016 American Academy of Neurology.)

Background: Brain amyloid β (Aβ) deposition and neurodegeneration have been documented in about 50-60% of cognitively healthy elderly individuals (aged 60 years or older). The long-term cognitive consequences of the presence of Alzheimer's disease pathology and neurodegeneration, and whether they have an independent or synergistic effect on cognition, are unclear. We aimed to characterise the long-term clinical and cognitive trajectories of healthy elderly individuals using a two-marker (Alzheimer's disease pathology and neurodegeneration) imaging construct., Methods: Between Nov 3, 2006, and Nov 25, 2014, 573 cognitively healthy individuals in Melbourne and Perth, Australia, (mean age 73·1 years [SD 6·2]; 58% women) were enrolled in the Australian Imaging, Biomarker and Lifestyle (AIBL) study. Alzheimer's disease pathology (A) was determined by measuring Aβ deposition by PET, and neurodegeneration (N) was established by measuring hippocampal volume using MRI. Individuals were categorised as A(-)N(-), A(+)N(-), A(+)N(+), or suspected non-Alzheimer's disease pathophysiology (A(-)N(+), SNAP). Clinical progression, hippocampal volume, standard neuropsychological tests, and domain-specific and global cognitive composite scores were assessed over 6 years of follow-up. Linear mixed effect models and a Cox proportional hazards model of survival were used to evaluate, compare, and contrast the clinical, cognitive, and volumetric trajectories of patients in the four AN categories., Findings: 50 (9%) healthy individuals were classified as A(+)N(+), 87 (15%) as A(+)N(-), 310 (54%) as A(-)N(-), and 126 (22%) as SNAP. APOE ε4 was more frequent in participants in the A(+)N(+) (27; 54%) and A(+)N(-) (42; 48%) groups than in the A(-)N(-) (66; 21%) and SNAP groups (23; 18%). The A(+)N(-) and A(+)N(+) groups had significantly faster cognitive decline than the A(-)N(-) group (0·08 SD per year for AIBL-Preclinical AD Cognitive Composite [PACC]; p<0·0001; and 0·25; p<0·0001; respectively). The A (+)N(+) group also had faster hippocampal atrophy than the A(-)N(-) group (0·04 cm(3) per year; p=0·02). The SNAP group generally did not show significant decline over time compared with the A(-)N(-) group (0·03 SD per year [p=0·19] for AIBL-PACC and a 0·02 cm(3) per year increase [p=0·16] for hippocampal volume), although SNAP was sometimes associated with lower baseline cognitive scores (0·20 SD less than A(-)N(-) for AIBL-PACC). Within the follow-up, 24% (n=12) of individuals in the A(+)N(+) group and 16% (n=14) in the A(+)N(-) group progressed to amnestic mild cognitive impairment or Alzheimer's disease, compared with 9% (n=11) in the SNAP group., Interpretation: Brain amyloidosis, a surrogate marker of Alzheimer's disease pathology, is a risk factor for cognitive decline and for progression from preclinical stages to symptomatic stages of the disease, with neurodegeneration acting as a compounding factor. However, neurodegeneration alone does not confer a significantly different risk of cognitive decline from that in the group with neither brain amyloidosis or neurodegeneration., Funding: CSIRO Flagship Collaboration Fund and the Science and Industry Endowment Fund (SIEF), National Health and Medical Research Council, the Dementia Collaborative Research Centres programme, McCusker Alzheimer's Research Foundation, and Operational Infrastructure Support from the Government of Victoria., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

See O'Sullivan and Vann (doi:10.1093/aww166) for a scientific commentary on this article.About 15% of patients clinically diagnosed with Alzheimer's disease do not show high tracer retention on amyloid positon emission tomography imaging. The present study investigates clinical and demographic features, patterns of brain atrophy and hypometabolism and longitudinal clinical trajectories of these patients. Forty amyloid-negative patients carrying a pre-scan diagnosis of Alzheimer's disease dementia from four centres were included (11/29 females/males; mean age = 67 ± 9). Detailed clinical histories, including the clinical diagnoses before and after the amyloid scan and at follow-up, were collected. Patients were classified according to their pre-scan clinical phenotype as amnestic (memory predominant), non-amnestic (predominant language, visuospatial or frontal symptoms), or non-specific (diffuse cognitive deficits). Demographic, clinical, neuropsychological, magnetic resonance imaging and (18)F-fluorodeoxyglucose positon emission tomography data were compared to 27 amyloid-positive typical Alzheimer's disease cases (14/13 females/males; mean age = 71 ± 10) and 29 amyloid-negative controls (15/14 females/males; mean age = 69 ± 12) matched for age, gender and education. There were 21 amnestic, 12 non-amnestic, and seven non-specific amyloid-negative Alzheimer's disease cases. Amyloid-negative subgroups did not differ in age, gender or education. After the amyloid scan, clinicians altered the diagnosis in 68% of amyloid-negative patients including 48% of amnestic versus 94% of non-amnestic and non-specific cases. Amnestic amyloid-negative cases were most often reclassified as frontotemporal dementia, non-amnestic as frontotemporal dementia or corticobasal degeneration, and non-specific as dementia with Lewy bodies or unknown diagnosis. The longer-term clinical follow-up was consistent with the post-scan diagnosis in most cases (90%), including in amnestic amyloid-negative cases whose post-positon emission tomography diagnosis remained Alzheimer's disease. While the non-amnestic and non-specific amyloid-negative cases usually showed patterns of atrophy and hypometabolism suggestive of another degenerative disorder, the amnestic amyloid-negative cases had subtle atrophy and hypometabolism, restricted to the retrosplenial/posterior cingulate cortex. Patients with a negative amyloid positon emission tomography scan following an initial clinical diagnosis of Alzheimer's disease have heterogeneous clinical presentations and neuroimaging profiles; a majority showed a clinical progression that was consistent with a neurodegenerative condition. In contrast, in the subgroup of amnestic amyloid-negative cases, the clinical presentation and follow-up usually remained consistent with Alzheimer's disease. An alternative diagnosis was not made in about half of the amnestic amyloid-negative cases, highlighting the need for a clinical framework and terminology to define these patients, who may have underlying limbic-predominant, non-amyloid-related pathologies., (© The Author (2016). Published by Oxford University Press on behalf of the Guarantors of Brain. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Unlabelled: A common quantitative output value for PET measures of β-amyloid (Aβ) binding across tracers and methods would allow better comparison of data across sites and application of universal diagnostic and prognostic values. A method has recently been developed that generates a unit of measurement called the centiloid. We applied this method to 2-[2-(18)F-fluoro-6-(methylamino)-3-pyridinyl]-1-benzofuran-5-ol ((18)F-NAV4694) and (11)C-Pittsburgh compound B ((11)C-PiB) Aβ images to derive the scaling factor required to express tracer binding in centiloids., Methods: Fifty-five participants, including 10 young controls (33 ± 7 y old), underwent both (11)C-PiB and (18)F-NAV4694 imaging no more than 3 mo apart, with the images acquired 50-70 min after tracer injection. The images were spatially normalized and analyzed using the standard centiloid method and regions (cortex and whole-cerebellum reference) downloaded from the Global Alzheimer Association Interactive Network website., Results: SUV ratios (SUVRs) showed a strong correlation in tracer binding ((18)F-NAV4694 SUVR = 1.09 × (11)C-PiB SUVR - 0.08, R(2) = 0.99). The equation to convert (18)F-NAV4694 to centiloids [100 × ((18)F-NAV4694 SUVR - 1.028)/1.174] was similar to a published equation for (11)C-PiB [100 × ((11)C-PiB SUVR - 1.009)/1.067]. In the young controls, the variance ratio ((18)F-NAV4694 centiloid SD divided by (11)C-PiB centiloid SD) was 0.85., Conclusion: The results for both (11)C-PiB and (18)F-NAV4694 can now be expressed in centiloids, an important step that should allow better clinical and research use of Aβ imaging. The standard centiloid method also showed that (18)F-NAV4694 has slightly higher Aβ binding and lower variance than (11)C-PiB, important properties for detecting early Aβ deposition and change over time., (© 2016 by the Society of Nuclear Medicine and Molecular Imaging, Inc.)

Introduction: The objective of this study was to determine the utility of subjective memory decline (SMD) to predict episodic memory change and rates of clinical progression in cognitively normal older adults with evidence of high β-amyloid burden (CN Aβ+)., Methods: Fifty-eight CN Aβ+ participants from the Australian Imaging, Biomarkers, and Lifestyle study responded to an SMD questionnaire and underwent comprehensive neuropsychological assessments. Participant data for three follow-up assessments were analyzed., Results: In CN Aβ+, subjects with high SMD did not exhibit significantly greater episodic memory decline than those with low SMD. High SMD was related to greater rates of progression to mild cognitive impairment or Alzheimer's disease (AD) dementia (hazard ratio = 5.1; 95% confidence interval, 1.4-20.0, P = .02) compared with low SMD. High SMD was associated with greater depressive symptomatology and smaller left hippocampal volume., Discussion: High SMD is a harbinger of greater rates of clinical progression in preclinical AD. Although SMD reflects broader diagnostic implications for CN Aβ+, more sensitive measures may be required to detect early subtle cognitive change., (Copyright © 2016 The Alzheimer's Association. Published by Elsevier Inc. All rights reserved.)

In vivo imaging of tau deposits is providing a better understanding of the temporal and spatial tau deposition in the brain, allowing a more comprehensive insight into the causes, diagnoses, and potentially treatment of tauopathies such as Alzheimer's disease, progressive supranuclear palsy, corticobasal syndrome, chronic traumatic encephalopathy, and some variants of frontotemporal lobar degeneration. The assessment of tau deposition in the brain over time will allow a deeper understanding of the relationship between tau and other variables such as cognition, genotype, and neurodegeneration, as well as assessing the role tau plays in ageing. Preliminary human studies suggest that tau imaging could also be used as a diagnostic, prognostic, and theranostic biomarker, as well as a surrogate marker for target engagement, patient recruitment, and efficacy monitoring for disease-specific therapeutic trials.

Unlabelled: Training for accurate image interpretation is essential for the clinical use of β-amyloid PET imaging, but the role of interpreter training and the accuracy of the algorithm for routine visual assessment of florbetaben PET scans are unclear. The aim of this study was to test the robustness of the visual assessment method for florbetaben scans, comparing efficacy readouts across different interpreters and training methods and against a histopathology standard of truth (SoT)., Methods: Analysis was based on data from an international open-label, nonrandomized, multicenter phase-3 study in patients with or without dementia (ClinicalTrials.gov: NCT01020838). Florbetaben scans were assessed visually and quantitatively, and results were compared with amyloid plaque scores. For visual assessment, either in-person training (n = 3 expert interpreters) or an electronic training method (n = 5 naïve interpreters) was used. Brain samples from participants who died during the study were used to determine the histopathologic SoT using Bielschowsky silver staining (BSS) and immunohistochemistry for β-amyloid plaques., Results: Data were available from 82 patients who died and underwent postmortem histopathology. When visual assessment results were compared with BSS + immunohistochemistry as SoT, median sensitivity was 98.2% for the in-person-trained interpreters and 96.4% for the e-trained interpreters, and median specificity was 92.3% and 88.5%, respectively. Median accuracy was 95.1% and 91.5%, respectively. On the basis of BSS only as the SoT, median sensitivity was 98.1% and 96.2%, respectively; median specificity was 80.0% and 76.7%, respectively; and median accuracy was 91.5% and 86.6%, respectively. Interinterpreter agreement (Fleiss κ) was excellent (0.89) for in-person-trained interpreters and very good (0.71) for e-trained interpreters. Median intrainterpreter agreement was 0.9 for both in-person-trained and e-trained interpreters. Visual and quantitative assessments were concordant in 88.9% of scans for in-person-trained interpreters and in 87.7% of scans for e-trained interpreters., Conclusion: Visual assessment of florbetaben images was robust in challenging scans from elderly end-of-life individuals. Sensitivity, specificity, and interinterpreter agreement were high, independent of expertise and training method. Visual assessment was accurate and reliable for detection of plaques using BSS and immunohistochemistry and well correlated with quantitative assessments., (© 2016 by the Society of Nuclear Medicine and Molecular Imaging, Inc.)

Psychological stress is associated with gastrointestinal (GI) distress. This secondary analysis from a randomised, double-blind, placebo-controlled study examined whether three different probiotics could normalise self-reported stress-associated GI discomfort and reduce overall self-reported stress. Undergraduate students (n=581) received Lactobacillus helveticus R0052, Bifidobacterium longum ssp. infantis R0033, Bifidobacterium bifidum R0071, or placebo. Participants self-reported 2 outcomes for a 6-week period, which included final academic exams: daily level of stress (0=no stress to 10=extremely stressed) and weekly three diarrhoea-related symptoms (DS, 1=no discomfort to 7=severe discomfort) using the GI Symptom Rating Scale. Self-reported stress was positively related to DS (P=0.0068). Mean DS scores were lower with B. bifidum versus placebo at week 2 at the average level of stress and the average body mass index (BMI). DS scores were lower with B. bifidum at week 5 versus week 0 and 1 and with B. infantis R0033 at week 6 versus week 0. DS scores were higher when antibiotics were used in the prior week with placebo (P=0.0092). DS were not different with or without antibiotic use with the probiotics. Only B. bifidum had an effect on self-reported stress scores (P=0.0086). The self-reported stress score was also dependent on hours of sleep per day where it decreased by 0.13 for each additional hour of sleep. During a stressful period, B. bifidum R0071 decreases DS and self-reported stress scores. This trial was registered at clinicaltrials.gov as NCT01709825.

Study Objectives: To evaluate the association between self-reported sleep quality and levels of brain β-amyloid (Aβ) burden, and to determine the effect of the apolipoprotein E (APOE) ε4 allele on any associations found., Methods: This study is a cross-sectional analysis of 184 cognitively healthy men and women aged over 60 y. We measured sleep quality factors: specifically, sleep duration, latency (time taken to fall asleep), disturbances, efficiency, daytime dysfunction, and overall sleep quality, using the Pittsburgh Sleep Quality Index. All participants underwent Aβ positron emission tomography imaging for the quantification of brain Aβ burden and were APOE genotyped. Linear regression analyses were used to evaluate the relationship between sleep quality factors and brain Aβ burden, adjusting for age, body mass index, cardiovascular disease, and symptoms of depression, with APOE ε4 carriage entered as a moderator., Results: Of the sleep factors, longer sleep latency was associated with higher levels of brain Aβ (B = 0.003 [standard error = 0.001], P = 0.02). APOE ε4 allele (carrier/noncarrier) did not moderate the relationship between sleep latency and brain Aβ burden., Conclusions: Our findings suggest a relationship between brain Aβ burden and sleep latency, independent of APOE ε4 genotype., (© 2016 Associated Professional Sleep Societies, LLC.)

Objective: As the absence of Aβ-related memory decline in APOE ε4 noncarriers may be due to the relative brevity of previous studies, we aimed to characterize Aβ-related cognitive decline over 72 months in APOE ε4 carriers and noncarriers who were cognitively normal (CN)., Methods: CN older adults (n = 423) underwent Aβ imaging and APOE genotyping. Participants completed comprehensive neuropsychological testing at baseline 18-, 36-, 54-, and 72-month assessments., Results: Relative to Aβ- CN ε4 noncarriers, both Aβ+ CN ε4 carriers and noncarriers showed significantly increased decline in measures of memory, language, and executive function as well as higher rates of progression to a clinical classification of mild cognitive impairment. Memory decline was greater in Aβ+ CN ε4 carriers than in Aβ+ CN ε4 noncarriers. No cognitive decline was evident in Aβ- CN ε4 carriers., Conclusions: In CN older adults, Aβ+ is associated with memory decline in ε4 noncarriers; however, the rate of this decline is much slower than that observed in ε4 carriers. These data indicate that the processes by which ε4 carriage increases the rate of Aβ-related cognitive decline occur in the preclinical stage of Alzheimer disease., (© 2016 American Academy of Neurology.)

Increased rates of brain atrophy measured from serial magnetic resonance imaging precede symptom onset in Alzheimer's disease and may be useful outcome measures for prodromal clinical trials. Appropriate trial design requires a detailed understanding of the relationships between β-amyloid load and accumulation, and rate of brain change at this stage of the disease. Fifty-two healthy individuals (72.3 ± 6.9 years) from Australian Imaging, Biomarkers and Lifestyle Study of Aging had serial (0, 18 m, 36 m) magnetic resonance imaging, (0, 18 m) Pittsburgh compound B positron emission tomography, and clinical assessments. We calculated rates of whole brain and hippocampal atrophy, ventricular enlargement, amyloid accumulation, and cognitive decline. Over 3 years, rates of whole brain atrophy (p < 0.001), left and right hippocampal atrophy (p = 0.001, p = 0.023), and ventricular expansion (p < 0.001) were associated with baseline β-amyloid load. Whole brain atrophy rates were also independently associated with β-amyloid accumulation over the first 18 months (p = 0.003). Acceleration of left hippocampal atrophy rate was associated with baseline β-amyloid load across the cohort (p < 0.02). We provide evidence that rates of atrophy are associated with both baseline β-amyloid load and accumulation, and that there is presymptomatic, amyloid-mediated acceleration of hippocampal atrophy. Clinical trials using rate of hippocampal atrophy as an outcome measure should not assume linear decline in the presymptomatic phase., (Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: APOEɛ4 genotype and aging have been identified as risk factors for Alzheimer's disease (AD). In addition, subjective memory complaints (SMC) might be a first clinical expression of the effect of AD pathology on cognitive functioning., Objective: To assess whether APOEɛ4 genotype, age, SMC, and episodic memory are risk factors for high amyloid-β (Aβ) burden in cognitively normal elderly., Methods: 307 cognitively normal participants (72.7 ± 6.8 years, 53% female, 55% SMC) from the Australian Imaging, Biomarkers and Lifestyle (AIBL) study underwent amyloid PET and APOE genotyping. Logistic regression analyses were performed to determine the association of APOEɛ4 genotype, age, SMC, and episodic memory with Aβ pathology., Results: Odds of high Aβ burden were greater at an older age (OR = 3.21; 95% CI = 1.68-6.14), when SMC were present (OR = 1.90; 95% CI = 1.03-3.48), and for APOEɛ4 carriers (OR = 7.49; 95% CI = 3.96-14.15), while episodic memory was not associated with odds of high Aβ burden. Stratified analyses showed that odds of SMC for high Aβ burden were increased in specifically APOEɛ4 carriers (OR = 4.58, 95% CI = 1.83-11.49) and younger participants (OR = 3.73, 95% CI = 1.39-10.01)., Conclusion: Aging, APOEɛ4 genotype, and SMC were associated with high Aβ burden. SMC were especially indicative of high Aβ burden in younger participants and in APOEɛ4 carriers. These findings suggest that selection based on the presence of SMC, APOEɛ4 genotype and age may help identify healthy elderly participants with high Aβ burden eligible for secondary prevention trials.

Diagnostic distinction of primary progressive aphasias (PPA) remains challenging, in particular for the logopenic (lvPPA) and nonfluent/agrammatic (naPPA) variants. Recent findings highlight that episodic memory deficits appear to discriminate these PPA variants from each other, as only lvPPA perform poorly on these tasks while having underlying amyloid pathology similar to that seen in amnestic dementias like Alzheimer's disease (AD). Most memory tests are, however, language based and thus potentially confounded by the prevalent language deficits in PPA. The current study investigated this issue across PPA variants by contrasting verbal and non-verbal episodic memory measures while controlling for their performance on a language subtest of a general cognitive screen. A total of 203 participants were included (25 lvPPA; 29 naPPA; 59 AD; 90 controls) and underwent extensive verbal and non-verbal episodic memory testing, with a subset of patients (n = 45) with confirmed amyloid profiles as assessed by Pittsburgh Compound B and PET. The most powerful discriminator between naPPA and lvPPA patients was a non-verbal recall measure (Rey Complex Figure delayed recall), with 81% of PPA patients classified correctly at presentation. Importantly, AD and lvPPA patients performed comparably on this measure, further highlighting the importance of underlying amyloid pathology in episodic memory profiles. The findings demonstrate that non-verbal recall emerges as the best discriminator of lvPPA and naPPA when controlling for language deficits in high load amyloid PPA cases.

Alzheimer's disease (AD) is a degenerative brain disorder and is the most common form of dementia. Minimally invasive approaches are required that combine biomarkers to identify individuals who are at risk of developing mild cognitive impairment (MCI) and AD, to appropriately target clinical trials for therapeutic discovery as well as lifestyle strategies aimed at prevention. Buccal mucosa cells from the Australian Imaging, Biomarkers and Lifestyle Flagship Study of Ageing cohort (n=60) were investigated for cytological markers that could be used to identify both MCI and AD individuals. Visual scoring of the buccal cytome demonstrated a significantly lower frequency of basal and karyorrhectic cells in the MCI group compared with controls. A high content, automated assay was developed using laser scanning cytometry to simultaneously measure cell types, nuclear DNA content and aneuploidy, neutral lipid content, putative Tau and amyloid-β (Aβ) in buccal cells. DNA content, aneuploidy, neutral lipids and Tau were similar in all groups. However, there was significantly lower Tau protein in both basal and karyolytic buccal cell types compared with differentiated buccal cells. Aβ, as measured by frequency of cells containing Aβ signal, as well as area and integral of Aβ signal, was significantly higher in the AD group compared with the control group. Buccal cell Aβ was correlated with mini-mental state examination (MMSE) scores (r = -0.436, P=0.001) and several blood-based biomarkers. Combining newly identified biomarkers from buccal cells with those already established may offer a potential route for more specific biomarker panels which may substantially increase the likelihood of better predictive markers for earlier diagnosis of AD.

The health benefits of nuts may, in part, be due to the fiber that provides substrate for the maintenance of a healthy and diverse microbiota. We hypothesized that consuming almonds would benefit immune status through improving diet quality and modulation of microbiota composition in parents and their children, while improving gastrointestinal function. In a crossover trial, 29 parents (35 ± 0.6 years) and their children (n = 29; 4 ± 0.2 years; pairs) consumed 1.5 and 0.5 oz, respectively, of almonds and/or almond butter or control (no almonds) for 3 weeks followed by 4-week washouts. Parents completed daily questionnaires of stool frequency and compliance with nut intake. The Gastrointestinal Symptom Response Scale was administered weekly. Participants provided stools for microbiota analysis and saliva for secretory immunoglobulin A. Serum antioxidant/proinflammatory balance was determined in parents. From weekly dietary recalls (Automated Self-Administered 24-Hour Dietary Recall), nutrient and energy intake were assessed and Healthy Eating Index-2010 scores were calculated. Consuming almonds increased total Healthy Eating Index score from 53.7 ± 1.8 to 61.4 ± 1.4 (parents) and 53.7 ± 2.6 to 61.4 ± 2.2 (children; P < .001). Minimal changes in gastrointestinal symptoms and no change in stool frequency were noted with the almond intervention. Microbiota was stable at the phylum and family level, but genus-level changes occurred with nut intake, especially in children. No differences were observed for immune markers. Although higher intakes of almonds or longer interventions may be needed to demonstrate effects on immune status, a moderate intake of almonds improves diet quality in adults and their young children and modulates microbiota composition., (Copyright © 2016 Elsevier Inc. All rights reserved.)

This study investigated signs of age related macular degeneration (AMD) in Alzheimer's disease (AD). These age-related diseases primarily affect different parts of the central nervous system but are substantially similar in terms of abnormal extracellular deposits, metabolic and oxidative stress, neuroinflammation and microvascular abnormalities. While AMD is a retinal disease, AD is reported to affect not only the brain but also the retina, with Aβ deposits, neurodegeneration and vascular changes. Large population based studies have provided conflicting results regarding the comorbidity of AD and AMD. This study investigated signs of AMD in a small but well characterized cohort from the Australian Imaging Biomarkers and Lifestyle study of aging (AIBL). The cohort consisted of 22 AD patients (age 70.2 ± 9.0 yrs, 13 male, 9 female) and 101 cognitively normal (CN) participants (age 71.3 ± 6.0 yrs, 40 male, 61 female). In comparison with the CN group, the AD group had a greater proportion of participants with early AMD (p < 0.0001, odds ratio 18.67, 95% CI 4.42 - 78.80). A logistic model for early AMD found a significant association with AD diagnosis (p < 0.0001), after adjusting for confounders (age, smoking, hypertension, high and low density lipoproteins, cataract surgery and APOE ε4 carrier status). The results of this study are consistent with an increased risk of AMD in AD. While the pathophysiology of these diseases are unclear, understanding the shared features between them may provide further knowledge about their pathogenesis and could lead to accelerated development of therapies for both diseases.

Background: Despite divergent clinical features, language and amnestic presentations of Alzheimer's disease (AD) appear to show comparable regional amyloid-β (Aβ) burden. By using a statistical network approach, we aimed to identify complex network patterns of Aβ deposition and explore the effect of apolipoprotein E (APOE) ε4 allele on cortical Aβ burden across AD phenotypes., Methods: Sixteen amnestic AD participants and 18 cases with logopenic-variant of primary progressive aphasia (lv-PPA) with a high cortical Aβ burden were selected. A comprehensive clinical assessment, Aβ imaging, and APOE genotyping were performed in all cases. Statistical network analysis was undertaken based on the estimation of sparse partial correlations of Aβ burden between cortical regions. Global and regional network statistical parameters as well as the effect of APOEε4 genotype on cortical Aβ were explored., Results: The two groups showed equivalent distribution of cortical amyloid burden and frequency of APOEε4 genotype. Statistical network analysis, however, demonstrated divergent connectivity properties. The lv-PPA group demonstrated higher mean network degree and shorter characteristic path length than the amnestic AD group. Amnestic AD cases showed connectivity hubs confined to the mesial temporal and prefrontal lobes bilaterally, whereas lv-PPA cases showed hubs scattered across the whole cortical mantle. An interaction effect on total Aβ burden between APOE genotype and AD presentations was also detected., Conclusions: The network analysis reveals interregional network differences not evident using a simple comparison of Aβ burden. This suggests that regional neurotoxic effects may explain the phenotypical differences in AD presentation and that these can be modulated by APOE genotype., (Copyright © 2016 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.)

Introduction: For early detection of Alzheimer's disease (AD), the field needs biomarkers that can be used to detect disease status with high sensitivity and specificity. Apolipoprotein J (ApoJ, also known as clusterin) has long been associated with AD pathogenesis through various pathways. The aim of this study was to investigate the potential of plasma apoJ as a blood biomarker for AD., Methods: Using the Australian Imaging, Biomarkers and Lifestyle (AIBL) study of aging, the present study assayed plasma apoJ levels over baseline and 18 months in 833 individuals. Plasma ApoJ levels were analyzed with respect to clinical classification, age, gender, apolipoprotein E (APOE) ε4 allele status, mini-mental state examination score, plasma amyloid beta (Aβ), neocortical Aβ burden (as measured by Pittsburgh compound B-positron emission tomography), and total adjusted hippocampus volume., Results: ApoJ was significantly higher in both mild cognitive impairment (MCI) and AD groups as compared with healthy controls (HC; P < .0001). ApoJ significantly correlated with both "standardized uptake value ratio" (SUVR) and hippocampus volume and weakly correlated with the plasma Aβ1-42/Aβ1-40 ratio. Plasma apoJ predicted both MCI and AD from HC with greater than 80% accuracy for AD and greater than 75% accuracy for MCI at both baseline and 18-month time points., Discussion: Mean apoJ levels were significantly higher in both MCI and AD groups. ApoJ was able to differentiate between HC with high SUVR and HC with low SUVR via APOE ε4 allele status, indicating that it may be included in a biomarker panel to identify AD before the onset of clinical symptoms.

Introduction: Cognitive composite scores developed for preclinical Alzheimer's disease (AD) often consist of multiple cognitive domains as they may provide greater sensitivity to detect β-amyloid (Aβ)-related cognitive decline than episodic memory (EM) composite scores alone. However, this has never been empirically tested. We compared the rate of cognitive decline associated with high Aβ (Aβ+) and very high Aβ (Aβ++) in cognitively normal (CN) older adults on three multidomain cognitive composite scores and one single-domain (EM) composite score., Methods: CN older adults (n = 423) underwent Aβ neuroimaging and completed neuropsychological assessments at baseline, and at 18-, 36-, 54-, and 72-month follow-ups. Four cognitive composite scores were computed: the ADCS-PACC (ADCS-Preclinical Alzheimer Cognitive Composite), ADCS-PACC without the inclusion of the mini-mental state examination (MMSE), an EM composite, and the Z-scores of Attention, Verbal fluency, and Episodic memory for Nondemented older adults (ZAVEN) composite., Results: Compared with Aβ+ CN older adults, Aβ++ CN older adults showed faster rates of decline across all cognitive composites, with the largest decline observed for ZAVEN composite (d = 1.07). Similarly, compared with Aβ- CN older adults, Aβ+ CN older adults also showed faster rates of cognitive decline, but only for the ADCS-PACC no MMSE (d = 0.43), EM (d = 0.53), and ZAVEN (d = 0.50) composites., Discussion: Aβ-related cognitive decline is best detected using validated neuropsychological instruments. Removal of the MMSE from the ADCS-PACC and replacing it with a test of executive function (verbal fluency; i.e., the ZAVEN) rendered this composite more sensitive even in detecting Aβ-related cognitive decline between Aβ+ and Aβ++ CN older adults.

Susceptibility-weighted imaging (SWI) is recognized as the preferred MRI technique for visualizing cerebral vasculature and related pathologies such as cerebral microbleeds (CMBs). Manual identification of CMBs is time-consuming, has limited reliability and reproducibility, and is prone to misinterpretation. In this paper, a novel computer-aided microbleed detection technique based on machine learning is presented: First, spherical-like objects (potential CMB candidates) with their corresponding bounding boxes were detected using a novel multi-scale Laplacian of Gaussian technique. A set of robust 3-dimensional Radon- and Hessian-based shape descriptors within each bounding box were then extracted to train a cascade of binary random forests (RF). The cascade consists of consecutive independent RF classifiers with low to high posterior probability constraints to handle imbalanced training sets (CMBs and non-CMBs), and to progressively improve detection rates. The proposed method was validated on 66 subjects whose CMBs were manually stratified into "possible" and "definite" by two medical experts. The proposed technique achieved a sensitivity of 87% and an average false detection rate of 27.1 CMBs per subject on the "possible and definite" set. A sensitivity of 93% and false detection rate of 10 CMBs per subject was also achieved on the "definite" set. The proposed automated approach outperforms state of the art methods, and promises to enhance manual expert screening. Benefits include improved reliability, minimization of intra-rater variability and a reduction in assessment time., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

FFQ are commonly used to examine the association between diet and disease. They are the most practical method for usual dietary data collection as they are relatively inexpensive and easy to administer. In Australia, the Cancer Council of Victoria FFQ (CCVFFQ) version 2 and the online Commonwealth Scientific and Industrial Research Organisation FFQ (CSIROFFQ) are used. The aim of our study was to establish the level of agreement between nutrient intakes captured using the online CSIROFFQ and the paper-based CCVFFQ. The CCVFFQ and the online CSIROFFQ were completed by 136 healthy participants. FFQ responses were analysed to give g per d intake of a range of nutrients. Agreement between twenty-six nutrient intakes common to both FFQ was measured by a variety of methods. Nutrient intake levels that were significantly correlated between the two FFQ were carbohydrates, total fat, Na and MUFA. When assessing ranking of nutrients into quintiles, on average, 56 % of the participants (for all nutrients) were classified into the same or adjacent quintiles in both FFQ, with the highest percentage agreement for sugar. On average, 21 % of participants were grossly misclassified by three or four quintiles, with the highest percentage misclassification for fibre and Fe. Quintile agreement was similar to that reported by other studies, and we concluded that both FFQ are suitable tools for dividing participants' nutrient intake levels into high- and low-consumption groups. Use of either FFQ was not appropriate for obtaining accurate estimates of absolute nutrient intakes.

Background: Recent evidence suggests that exercise plays a role in cognition and that the posterior cingulate cortex (PCC) can be divided into dorsal and ventral subregions based on distinct connectivity patterns., Aims: To examine the effect of physical activity and division of the PCC on brain functional connectivity measures in subjective memory complainers (SMC) carrying the epsilon 4 allele of apolipoprotein E (APOE ε 4) allele., Method: Participants were 22 SMC carrying the APOE ε 4 allele ( ε 4+; mean age 72.18 years) and 58 SMC non-carriers ( ε 4-; mean age 72.79 years). Connectivity of four dorsal and ventral seeds was examined. Relationships between PCC connectivity and physical activity measures were explored., Results: ε 4+ individuals showed increased connectivity between the dorsal PCC and dorsolateral prefrontal cortex, and the ventral PCC and supplementary motor area (SMA). Greater levels of physical activity correlated with the magnitude of ventral PCC-SMA connectivity., Conclusions: The results provide the first evidence that ε 4+ individuals at increased risk of cognitive decline show distinct alterations in dorsal and ventral PCC functional connectivity., Declaration of Interest: D.A. has served on scientific advisory boards for Novartis, Eli Lilly, Janssen, Prana and Pfizer, and as Editor-in-Chief for International Psychogeriatrics; received speaker honoraria from Pfizer and Lundbeck, and research support from Eli Lilly, GlaxoSmithKline, Forest Laboratories, Novartis, and CSIRO. C.L.M. has received consulting fees from Eli Lilly and Prana Biotechnology, and has stock ownership in Prana Biotechnology. C.C.R. has received consultancy payments from Roche and Piramal, and research support from Avid Radiopharmaceuticals, Eli Lilly, GE Healthcare, Piramal and Navidea for amyloid imaging. C.S. has provided clinical consultancy and been on scientific advisory committees for the Australian CSIRO, Alzheimer's Australia, University of Melbourne and other relationships, which are subject to confidentiality clauses; she has been a named Chief Investigator on investigator-driven collaborative research projects in partnership with Pfizer, Merck, Piramal, Bayer and GE Healthcare. Her research programme has received support from the National Health and Medical Research Council Alzheimer's Association, Collier Trust, Scobie and Claire McKinnon Foundation, JO and JR Wicking Trust, Shepherd Foundation, Brain Foundation, Mason Foundation, Ramaciotti Foundation, Alzheimer's Australia and the Royal Australian College of Physicians., Copyright and Usage: © The Royal College of Psychiatrists 2015. This is an open access article distributed under the terms of the Creative Commons Non-Commercial, No Derivatives (CC BY-NC-ND) licence.

Accumulation of β-amyloid (Aβ) in the brain is associated with memory decline in healthy individuals as a prelude to Alzheimer's disease (AD). Genetic factors may moderate this decline. We examined the role of apolipoprotein E (ɛ4 carrier[ɛ4(+)], ɛ4 non-carrier[ɛ4(-)]) and brain-derived neurotrophic factor (BDNF(Val/Val), BDNF(Met)) in the extent to which they moderate Aβ-related memory decline. Healthy adults (n=333, Mage=70 years) enrolled in the Australian Imaging, Biomarkers and Lifestyle study underwent Aβ neuroimaging. Neuropsychological assessments were conducted at baseline, 18-, 36- and 54-month follow-ups. Aβ positron emission tomography neuroimaging was used to classify participants as Aβ(-) or Aβ(+). Relative to Aβ(-)ɛ4(-), Aβ(+)ɛ4(+) individuals showed significantly faster rates of cognitive decline over 54 months across all domains (d=0.40-1.22), while Aβ(+)ɛ4(-) individuals showed significantly faster decline only on verbal episodic memory (EM). There were no differences in rates of cognitive change between Aβ(-)ɛ4(-) and Aβ(-)ɛ4(+) groups. Among Aβ(+) individuals, ɛ4(+)/BDNF(Met) participants showed a significantly faster rate of decline on verbal and visual EM, and language over 54 months compared with ɛ4(-)/BDNF(Val/Val) participants (d=0.90-1.02). At least two genetic loci affect the rate of Aβ-related cognitive decline. Aβ(+)ɛ4(+)/BDNF(Met) individuals can expect to show clinically significant memory impairment after 3 years, whereas Aβ(+)ɛ4(+)/BDNF(Val/Val) individuals can expect a similar degree of impairment after 10 years. Little decline over 54 months was observed in the Aβ(-) and Aβ(+) ɛ4(-) groups, irrespective of BDNF status. These data raise important prognostic issues in managing preclinical AD, and should be considered in designing secondary preventative clinical trials.

Alzheimer's disease is a chronic illness with long preclinical and prodromal phases (20 years) and an average clinical duration of 8-10 years. The disease has an estimated prevalence of 10-30% in the population >65 years of age with an incidence of 1-3%. Most patients with Alzheimer's disease (>95%) have the sporadic form, which is characterized by a late onset (80-90 years of age), and is the consequence of the failure to clear the amyloid-β (Aβ) peptide from the interstices of the brain. A large number of genetic risk factors for sporadic disease have been identified. A small proportion of patients (<1%) have inherited mutations in genes that affect processing of Aβ and develop the disease at a much younger age (mean age of ∼45 years). Detection of the accumulation of Aβ is now possible in preclinical and prodromal phases using cerebrospinal fluid biomarkers and PET. Several approved drugs ameliorate some of the symptoms of Alzheimer's disease, but no current interventions can modify the underlying disease mechanisms. Management is focused on the support of the social networks surrounding the patient and the treatment of any co-morbid illnesses, such as cerebrovascular disease.

High levels of β-amyloid (Aβ) in the brain and carriage of the APOE ε4 allele have each been linked to cognitive impairment in cognitively normal (CN) older adults. However, the relationship between these two biomarkers and cognitive decline is unclear. The aim of this study was to investigate the relationship between cerebral Aβ level, APOE ε4 carrier status, and cognitive decline over 18 months, in 317 cognitively healthy (CN) older adults (47.6% males, 52.4% females) aged between 60 and 89 years (Mean = 69.9, SD = 6.8). Cognition was assessed using the Cogstate Brief Battery (CBB) and the California Verbal Learning Test, Second Edition (CVLT-II). Planned comparisons indicated that CN older adults with high Aβ who were also APOE ε4 carriers demonstrated the most pronounced decline in learning and working memory. In CN older adults who were APOE ε4 non-carriers, high Aβ was unrelated to cognitive decline in learning and working memory. Carriage of APOE ε4 in CN older adults with low Aβ was associated with a significantly increased rate of decline in learning and unexpectedly, improved cognitive performance on measures of verbal episodic memory over 18 months. These results suggest that Aβ and APOE ε4 interact to increase the rate of cognitive decline in CN older adults and provide further support for the use of Aβ and APOE ε4 as biomarkers of early Alzheimer's disease.

Unlabelled: Alzheimer disease is the cause of up to one-third of cases of primary progressive aphasia or corticobasal syndrome. The primary objective of this study was to determine the accuracy of 18F-FDG PET metabolic imaging for the detection of Alzheimer disease in patients with primary progressive aphasia or corticobasal syndrome., Methods: A cohort of patients (n=94), including those with an expert clinical diagnosis of logopenic (n=19), nonfluent (n=16), or semantic (n=13) variants of primary progressive aphasia, corticobasal syndrome (n=14), or Alzheimer disease (n=24), underwent 18F-FDG metabolic and 11C-labeled Pittsburgh compound B (11C-PiB) amyloid PET brain imaging. 18F-FDG PET scans interpreted with Neurostat and 3D-SSP displays were classified as revealing Alzheimer disease or "other" by interpreters who were unaware of the clinical assessments and 11C-PiB PET results. 11C-PiB PET imaging was considered to be the diagnostic reference standard, with a threshold standardized uptake value ratio of 1.5 being indicative of Alzheimer disease pathology. To address possible bias from subgroup selection for the Alzheimer disease binary classifier, we calculated both conventional and balanced accuracies., Results: Diagnoses of Alzheimer disease based on 18F-FDG PET resulted in 84% accuracy (both conventional and balanced). In comparison, diagnoses based on clinical assessments resulted in 65% conventional accuracy and 67% balanced accuracy., Conclusion: Brain 18F-FDG PET scans interpreted with Neurostat and 3D-SSP displays accurately detected Alzheimer disease in patients with primary progressive aphasia or corticobasal syndrome as focal-onset dementias. In such diagnostically challenging cohorts, (18)F-FDG PET imaging can provide more accurate diagnoses, enabling more appropriate therapy., (© 2015 by the Society of Nuclear Medicine and Molecular Imaging, Inc.)

There is no consensus for a blood-based test for the early diagnosis of Alzheimer's disease (AD). Expression profiling of small non-coding RNA's, microRNA (miRNA), has revealed diagnostic potential in human diseases. Circulating miRNA are found in small vesicles known as exosomes within biological fluids such as human serum. The aim of this work was to determine a set of differential exosomal miRNA biomarkers between healthy and AD patients, which may aid in diagnosis. Using next-generation deep sequencing, we profiled exosomal miRNA from serum (N=49) collected from the Australian Imaging, Biomarkers and Lifestyle Flagship Study (AIBL). Sequencing results were validated using quantitative reverse transcription PCR (qRT-PCR; N=60), with predictions performed using the Random Forest method. Additional risk factors collected during the 4.5-year AIBL Study including clinical, medical and cognitive assessments, and amyloid neuroimaging with positron emission tomography were assessed. An AD-specific 16-miRNA signature was selected and adding established risk factors including age, sex and apolipoprotein ɛ4 (APOE ɛ4) allele status to the panel of deregulated miRNA resulted in a sensitivity and specificity of 87% and 77%, respectively, for predicting AD. Furthermore, amyloid neuroimaging information for those healthy control subjects incorrectly classified with AD-suggested progression in these participants towards AD. These data suggest that an exosomal miRNA signature may have potential to be developed as a suitable peripheral screening tool for AD.

Background: Evaluation of brain β-amyloid by positron emission tomography (PET) imaging can assist in the diagnosis of Alzheimer disease (AD) and other dementias., Methods: Open-label, nonrandomized, multicenter, phase 3 study to validate the (18)F-labeled β-amyloid tracer florbetaben by comparing in vivo PET imaging with post-mortem histopathology., Results: Brain images and tissue from 74 deceased subjects (of 216 trial participants) were analyzed. Forty-six of 47 neuritic β-amyloid-positive cases were read as PET positive, and 24 of 27 neuritic β-amyloid plaque-negative cases were read as PET negative (sensitivity 97.9% [95% confidence interval or CI 93.8-100%], specificity 88.9% [95% CI 77.0-100%]). In a subgroup, a regional tissue-scan matched analysis was performed. In areas known to strongly accumulate β-amyloid plaques, sensitivity and specificity were 82% to 90%, and 86% to 95%, respectively., Conclusions: Florbetaben PET shows high sensitivity and specificity for the detection of histopathology-confirmed neuritic β-amyloid plaques and may thus be a valuable adjunct to clinical diagnosis, particularly for the exclusion of AD., Trial Registration: ClinicalTrials.govNCT01020838., (Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.)

The Alzheimer's Disease Neuroimaging Initiative (ADNI), launched in 2004, has worked to accelerate drug development by validating imaging and blood/cerebrospinal fluid biomarkers for Alzheimer's disease clinical treatment trials. ADNI is a naturalistic (nontreatment) multisite longitudinal study. A true public-private partnership, the initiative has set a new standard for data sharing without embargo and for the use of biomarkers in dementia research. The ADNI effort in North America is not the only such effort in the world. The Alzheimer's Association recognized these global efforts and formed Worldwide ADNI (WW-ADNI). By creating a platform for international collaboration and cooperation, WW-ADNI's goals are to harmonize projects and results across geographical regions and to facilitate data management and availability to investigators around the world. WW-ADNI projects include those based in North America, Europe, Japan, Australia, Korea, and Argentina., (Copyright © 2015 The Alzheimer's Association. Published by Elsevier Inc. All rights reserved.)