Memory complaints are related to Alzheimer disease pathology in older persons

Memory concerns in the early Alzheimer's disease prodrome: Regional association with tau deposition

Introduction

Relationship between self– and informant memory concerns and tau aggregation was assessed in adults at risk for Alzheimer's disease (AD).

Methods

Regional mean standardized uptake value ratios were extracted from [¹⁸F]flortaucipir positron emission tomography (PET) scans of 82 at-risk adults in the Alzheimer's Disease Neuroimaging Initiative (ADNI) cohort. Associations between self– and informant ECog memory scores and tau aggregation were analyzed on both regional and voxelwise bases. Analyses were completed both on the whole sample and restricted to amyloid-positive individuals only.

Results

Memory concerns were associated with tau aggregation. Self-perception was more associated with frontal tau. In contrast, informant scores were more associated with parietal tau. This source-by-region interaction was more prominent in amyloid-positive participants and observed in both regional and voxelwise analyses.

Discussion

Quantitative assessment of perceived memory functioning may be useful for screening older adults at risk for Alzheimer's disease. Individuals and their informants may provide complementary information relating to the anatomical distribution of tau.

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Both self– and informant memory concerns are associated with tau aggregation in at-risk adults.

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Self-concerns are more associated with frontal tau compared to a parietal pattern for informant concerns.

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This pattern is strongest in amyloid-positive participants.

Subjective Cognitive Decline Modifies the Relationship Between Cerebral Blood Flow and Memory Function in Cognitively Normal Older Adults

OBJECTIVES

Subjective cognitive decline (SCD), or self-reported cognitive decline despite normal neuropsychological test performance, is a risk factor for objective cognitive decline and Alzheimer's disease (AD). While brain mechanisms contributing to SCD are not well defined, studies show associations with vascular risk factors and altered cerebral blood flow (CBF), raising the hypothesis that those with SCD might be experiencing vascular dysregulation, or a disruption in the normal relationship between CBF and cognition. We examined whether the association between CBF and verbal memory performance differs between those with SCD (SCD+) and those without SCD (SCD-).

METHODS

Linear mixed-effects models were used to investigate whether the voxel-wise relationship between arterial spin labeling (ASL) MRI-measured CBF and verbal memory performance was modified by SCD among a group of 70 cognitively normal older adults (35 SCD+, 35 SCD-; mean age=72) matched on age, gender, and symptoms of depression.

RESULTS

Results indicated that the SCD- group exhibited positive associations between verbal memory and CBF within the posterior cingulate cortex, middle temporal gyrus, and inferior frontal gyrus, whereas the SCD+ group displayed negative associations between verbal memory and CBF within the posterior cingulate cortex, middle temporal gyrus, hippocampus, fusiform gyrus, and inferior frontal gyrus.

CONCLUSIONS

Findings suggest that, while higher CBF is supportive of memory function in those without SCD, higher CBF may no longer support memory function in those presenting with SCD, perhaps reflecting neurovascular dysregulation. (JINS, 2018, 24, 213-223).

Meditation and Music Improve Memory and Cognitive Function in Adults with Subjective Cognitive Decline: A Pilot Randomized Controlled Trial

BACKGROUND

While effective therapies for preventing or slowing cognitive decline in at-risk populations remain elusive, evidence suggests mind-body interventions may hold promise.

OBJECTIVES

In this study, we assessed the effects of Kirtan Kriya meditation (KK) and music listening (ML) on cognitive outcomes in adults experiencing subjective cognitive decline (SCD), a strong predictor of Alzheimer's disease.

METHODS

Sixty participants with SCD were randomized to a KK or ML program and asked to practice 12 minutes/day for 3 months, then at their discretion for the ensuing 3 months. At baseline, 3 months, and 6 months we measured memory and cognitive functioning [Memory Functioning Questionnaire (MFQ), Trail-making Test (TMT-A/B), and Digit-Symbol Substitution Test (DSST)].

RESULTS

The 6-month study was completed by 53 participants (88%). Participants performed an average of 93% (91% KK, 94% ML) of sessions in the first 3 months, and 71% (68% KK, 74% ML) during the 3-month, practice-optional, follow-up period. Both groups showed marked and significant improvements at 3 months in memory and cognitive performance (MFQ, DSST, TMT-A/B; p's≤0.04). At 6 months, overall gains were maintained or improved (p's≤0.006), with effect sizes ranging from medium (DSST, ML group) to large (DSST, KK group; TMT-A/B, MFQ). Changes were unrelated to treatment expectancies and did not differ by age, gender, baseline cognition scores, or other factors.

CONCLUSIONS

Findings of this preliminary randomized controlled trial suggest practice of meditation or ML can significantly enhance both subjective memory function and objective cognitive performance in adults with SCD, and may offer promise for improving outcomes in this population.

Association between subjective memory assessment and associative memory performance: Role of ad risk factors

Decline in associative memory abilities is a common cognitive complaint among older adults and is detectable in both normal aging and in prodromal Alzheimer's disease (AD). Subjective memory (SM) complaints may serve as an earlier marker of these mnemonic changes; however, previous research examining the predictive utility of SM to observed memory performance yielded inconsistent results. This inconsistency is likely due to other sources of variance that occur with memory decline such as mood/depression issues, presence of apolipoprotein E (APOE ε4) genotype, or beta-amyloid deposition. Here we examine the relationship between SM and associative memory ability in the context of factors that increase susceptibility to AD in 195 healthy adults (79 men) aged 20-94 years. Participants completed an SM questionnaire, a mood/depression scale, two associative memory tests (a word-pair and a name-face test), and were genotyped for APOE ε4. PET-amyloid imaging data were collected for a subset of those over 50 years of age (N = 74). We found that SM predicted performance on both associative memory tests even after covarying for age, sex, mood, and APOE ε4 status. Interestingly, for the name-face associative task, increased SM concerns predicted memory performance selectively in participants over the age of 60, with the APOEε4 risk group showing the strongest effect. Finally, men with higher beta-amyloid deposition reported more memory complaints. Our findings suggest that SM reliably tracks memory performance, even in cognitively healthy adults, and may reflect an increased risk for AD. (PsycINFO Database Record

Tau in Late-Life Depression: A Systematic Review and Meta-Analysis

A lifetime history of major depressive disorder (MDD) increases the risk of developing Alzheimer's disease, of which neurofibrillary tangles due to abnormal tau proteins are a hallmark. We systematically reviewed the literature on tau in MDD and identified 49 relevant articles spanning a number of modalities, including cerebrospinal fluid (CSF) analysis, positron emission tomography, and clinicopathological correlation. We compared CSF total and phosphorylated tau proteins in MDD and controls using a meta-analytic approach. We found no difference in total or phosphorylated tau in MDD. We also found no difference in a comparison of a subgroup excluding studies with significant age differences. Positron emission tomography studies lacked specificity. Clinicopathological studies failed to associate neurofibrillary tangles with MDD. The available data on tau in MDD is limited. The involvement of tau in a subset of MDD cannot be ruled out and requires prospective exploration.

Religious Orders Study and Rush Memory and Aging Project

BACKGROUND

The Religious Orders Study and Rush Memory and Aging Project are both ongoing longitudinal clinical-pathologic cohort studies of aging and Alzheimer's disease (AD).

OBJECTIVES

To summarize progress over the past five years and its implications for understanding neurodegenerative diseases.

METHODS

Participants in both studies are older adults who enroll without dementia and agree to detailed longitudinal clinical evaluations and organ donation. The last review summarized findings through the end of 2011. Here we summarize progress and study findings over the past five years and discuss new directions for how these studies can inform on aging and AD in the future.

RESULTS

We summarize 1) findings on the relation of neurobiology to clinical AD; 2) neurobiologic pathways linking risk factors to clinical AD; 3) non-cognitive AD phenotypes including motor function and decision making; 4) the development of a novel drug discovery platform.

CONCLUSION

Complexity at multiple levels needs to be understood and overcome to develop effective treatments and preventions for cognitive decline and AD dementia.

Asymmetry of Hippocampus and Amygdala Defect in Subjective Cognitive Decline Among the Community Dwelling Chinese

Background: Subjective cognitive decline (SCD) may be the first clinical sign of Alzheimer's disease (AD). SCD individuals with normal cognition may already have significant medial temporal lobe atrophy. However, few studies have been devoted to exploring the alteration of left-right asymmetry with hippocampus and amygdala in SCD. The aim of this study was to compare SCD individuals with amnestic mild cognitive impairment (MCI) patients and the normal population for volume and asymmetry of hippocampus, amygdala and temporal horn, and to assess their relationship with cognitive function in elderly population living in China. Methods: 111 SCD, 30 MCI, and 67 healthy controls (HC) underwent a standard T1-weighted MRI, from which the volumes of the hippocampus and amygdala were calculated and compared. Then we evaluated the pattern and extent of asymmetry in hippocampus and amygdala of these samples. Furthermore, we also investigated the relationship between the altered brain regions and cognitive function. Results: Among the three groups, SCD showed more depressive symptoms (p < 0.001) and higher percentage of heart disease (16.4% vs. 35.1%, p = 0.007) than controls. In terms of brain data, significant differences were found in the volume and asymmetry of both hippocampus and amygdala among the three groups (P < 0.05). In logistic analysis controlled by age, gender, education level, depression symptoms, anxiety symptom, somatic disease and lifestyle in terms of smoking, both SCD and MCI individuals showed significant decreased right hippocampal and amygdala volume than controls. For asymmetry pattern, a ladder-shaped difference of left-larger-than-right asymmetry was found in amygdala with MCI>SCD>HC, and an opposite asymmetry of left-less-than-right pattern was found with HC>SCD>MCI in hippocampus. Furthermore, correlation was shown between the volume of right hippocampus and right amygdala with MMSE and MoCA in SCD group. Conclusion: Our results supported that SCD individuals are biologically distinguishable from HC, and this may relate to cognitive impairment, although more longitudinal studies are need to investigate this further.Moreover, different levels of asymmetry in hippocampus and amygdala might be a potential dividing factor to differentiate clinical diagnosis.

Region-Specific Association of Subjective Cognitive Decline With Tauopathy Independent of Global β-Amyloid Burden

Importance

The ability to explore associations between reports of subjective cognitive decline (SCD) and biomarkers of early Alzheimer disease (AD) pathophysiologic processes (accumulation of neocortical β-amyloid [Aβ] and tau) provides an important opportunity to understand the basis of SCD and AD risk.

Objective

To examine associations between SCD and global Aβ and tau burdens in regions of interest in clinically healthy older adults.

Design, Setting, and Participants

This imaging substudy of the Harvard Aging Brain Study included 133 clinically healthy older participants (Clinical Dementia Rating Scale global scores of 0) participating in the Harvard Aging Brain Study who underwent cross-sectional flortaucipir F 18 (previously known as AV 1451, T807) positron emission tomography (FTP-PET) imaging for tau and Pittsburgh compound B carbon 11-labeled PET (PiB-PET) imaging for Aβ. The following 2 regions for tau burden were identified: the entorhinal cortex, which exhibits early signs of tauopathy, and the inferior temporal region, which is more closely associated with AD-related pathologic mechanisms. Data were collected from June 11, 2012, through April 7, 2016.

Main Outcomes and Measures

Subjective cognitive decline was measured using a previously published method of z-transforming subscales from the Memory Functioning Questionnaire, the Everyday Cognition battery, and a 7-item questionnaire. The Aβ level was measured according to a summary distribution volume ratio of frontal, lateral temporal and parietal, and retrosplenial PiB-PET tracer uptake. The FTP-PET measures were computed as standardized uptake value ratios. Linear regression models focused on main and interactive effects of Aβ, entorhinal cortical, and inferior temporal tau on SCD, controlling for age, sex, educational attainment, and Geriatric Depression Scale score.

Results

Of the 133 participants, 75 (56.3%) were women and 58 (43.6%) were men; mean (SD) age was 76 (6.9) years (range, 55-90 years). Thirty-nine participants (29.3%) exhibited a high Aβ burden. Greater SCD was associated with increasing entorhinal cortical tau burden (β = 0.35; 95% CI, 0.19-.52; P < .001) and Aβ burden (β = 0.24; 95% CI, 0.08-.40; P = .005), but not inferior temporal tau burden (β = 0.10; 95% CI, -0.08 to 0.28; P = .27). This association between entorhinal cortical tau burden and SCD was largely unchanged after accounting for Aβ burden (β = 0.36; 95% CI, 0.15-.58; P = .001), and no interaction influenced SCD (β = -0.36; 95% CI, -0.34 to 0.09; P = .25). An exploratory post hoc whole-brain analysis also indicated that SCD was predominantly associated with greater tau burden in the entorhinal cortex.

Conclusions and Relevance

Subjective cognitive decline is indicative of accumulation of early tauopathy in the medial temporal lobe, specifically in the entorhinal cortex, and to a lesser extent, elevated global levels of Aβ. Our findings suggest multiple underlying pathways that motivate SCD that do not necessarily interact to influence SCD endorsement. As such, multiple biological factors must be considered when assessing SCD in clinically healthy older adults.

Subjective memory complaints are associated with brain activation supporting successful memory encoding

Subjective memory complaints, the perceived decline in cognitive abilities in the absence of clinical deficits, may precede Alzheimer's disease. Individuals with subjective memory complaints show differential brain activation during memory encoding; however, whether such differences contribute to successful memory formation remains unclear. Here, we investigated how subsequent memory effects, activation which is greater for hits than misses during an encoding task, differed between healthy older adults aged 50 to 85 years with (n = 23) and without (n = 41) memory complaints. Older adults with memory complaints, compared to those without, showed lower subsequent memory effects in the occipital lobe, superior parietal lobe, and posterior cingulate cortex. In addition, older adults with more memory complaints showed a more negative subsequent memory effects in areas of the default mode network, including the posterior cingulate cortex, precuneus, and ventromedial prefrontal cortex. Our findings suggest that for successful memory formation, older adults with subjective memory complaints rely on distinct neural mechanisms which may reflect an overall decreased task-directed attention.

Subjective cognitive decline and β-amyloid burden predict cognitive change in healthy elderly

OBJECTIVE

To assess in a longitudinal study whether subjective cognitive decline (SCD) and brain β-amyloid (Aβ) contribute unique information to cognitive decline.

METHODS

One hundred thirty-six healthy elderly from the Berkeley Aging Cohort Study were followed up for a mean of 4 years. SCD and affective measures were generated from the Geriatric Depression Scale (GDS) with factor analysis on data from a larger set of 347 healthy, nondepressed (GDS <11) elderly individuals. Cognition was summarized with previously validated factor scores. Pittsburgh compound B (PiB)-PET scans were acquired to determine the presence (PiB+) or absence (PiB-) of Aβ pathology. Mixed models were used to assess the independent and interactive effects of SCD, affective features, PiB status, and time on cognition, with adjustment for demographic variables.

RESULTS

SCD score demonstrated good construct validity compared to an existing measure of subjective memory and was partially explained by several lower-order measurements. Mixed models revealed that SCD interacted with PiB status to predict change in episodic memory and global cognition over time, with adjustment for affective features. PiB+ individuals with more severe SCD demonstrated the steepest cognitive decline. Worse SCD predicted faster decline in working memory independently of PiB status. No such effects were seen for affective scores when adjusted for SCD.

CONCLUSIONS

PiB+ individuals with SCD are at greatest risk of cognitive decline. Evidence for amyloid alone is not sufficient to indicate risk of rapid cognitive decline in healthy elderly. Effects of GDS on cognitive decline in nondepressed cohorts may be driven by SCD rather than subsyndromal depression.

Regional patterns of gray matter volume, hypometabolism, and beta-amyloid in groups at risk of Alzheimer's disease

Alzheimer's disease (AD) is characterized by the presence of β-amyloid (Aβ) deposition and neurodegeneration. To seek for signs of such pathologies, we compared regional biomarker degrees and patterns of Aβ deposition, glucose hypometabolism, and gray matter volume (GMV) reduction in 3 groups at risk of AD. In elderly carriers of the apolipoprotein E ε4 (APOE4, n = 17), patients with subjective cognitive decline (n = 16), and patients with mild cognitive impairment (n = 30), head-to-head intermodality comparisons were performed on cross-sectional structural magnetic resonance images as well as 18F-fluorodeoxyglucose and 18F-florbetapir positron emission tomography scans. In mild cognitive impairment patients, 3 distinct biomarker patterns were recovered, similarly seen in AD patients: (1) in medial temporal regions, local GMV reduction exceeded hypometabolism, (2) in temporoparietal regions, hypometabolism predominated over GMV reduction, and (3) in frontal regions, Aβ deposition exceeded GMV reduction and hypometabolism. In subjective cognitive decline patients, only pattern 1 was detected, while APOE4 carriers demonstrated only pattern 3. Our findings highlight that regional AD-like biomarker patterns may vary across different at-risk populations, potentially reflecting differential mediators of these risks.

Subjective Memory Change, Mood, and Cerebrovascular Risk Factors in Older African Americans

OBJECTIVE

Subjective memory change (SMC) in older individuals may represent a harbinger of cognitive decline. This study examined the factors associated with SMC in older African Americans (AA), who have greater risk of developing dementia. We predicted that symptoms of depression and anxiety, as well as the total number of cerebrovascular risk factors (tCVRFs), but not performances on objective memory measures, would be positively associated with SMC.

METHODS

Ninety-six AA completed brief cognitive testing and answered questions about mood and memory at their primary care appointment. Vascular data were obtained from medical records.

RESULTS

Symptoms of depression and anxiety, but not performances on objective memory measures, were positively associated with SMC, t(χ²(1) = 16.55 and 12.94, respectively, both P < .001). In nondepressed participants, the tCVRF was important in distinguishing between those with and without SMC.

CONCLUSIONS

In older AA, symptoms of depression or anxiety were associated with SMC. In nondepressed AA, the tCVRFs were important in distinguishing between those with and without SMC.

Entorhinal Cortex: Antemortem Cortical Thickness and Postmortem Neurofibrillary Tangles and Amyloid Pathology

BACKGROUND AND PURPOSE

The entorhinal cortex, a critical gateway between the neocortex and hippocampus, is one of the earliest regions affected by Alzheimer disease-associated neurofibrillary tangle pathology. Although our prior work has automatically delineated an MR imaging-based measure of the entorhinal cortex, whether antemortem entorhinal cortex thickness is associated with postmortem tangle burden within the entorhinal cortex is still unknown. Our objective was to evaluate the relationship between antemortem MRI measures of entorhinal cortex thickness and postmortem neuropathological measures.

MATERIALS AND METHODS

We evaluated 50 participants from the Rush Memory and Aging Project with antemortem structural T1-weighted MR imaging and postmortem neuropathologic assessments. Here, we focused on thickness within the entorhinal cortex as anatomically defined by our previously developed MR imaging parcellation system (Desikan-Killiany Atlas in FreeSurfer). Using linear regression, we evaluated the association between entorhinal cortex thickness and tangles and amyloid-β load within the entorhinal cortex and medial temporal and neocortical regions.

RESULTS

We found a significant relationship between antemortem entorhinal cortex thickness and entorhinal cortex (P = .006) and medial temporal lobe tangles (P = .002); we found no relationship between entorhinal cortex thickness and entorhinal cortex (P = .09) and medial temporal lobe amyloid-β (P = .09). We also found a significant association between entorhinal cortex thickness and cortical tangles (P = .003) and amyloid-β (P = .01). We found no relationship between parahippocampal gyrus thickness and entorhinal cortex (P = .31) and medial temporal lobe tangles (P = .051).

CONCLUSIONS

Our findings indicate that entorhinal cortex-associated in vivo cortical thinning may represent a marker of postmortem medial temporal and neocortical Alzheimer disease pathology.

Fun cube based brain gym cognitive function assessment system

The aim of this study is to design and develop a fun cube (FC) based brain gym (BG) cognitive function assessment system using the wireless sensor network and multimedia technologies. The system comprised (1) interaction devices, FCs and a workstation used as interactive tools for collecting and transferring data to the server, (2) a BG information management system responsible for managing the cognitive games and storing test results, and (3) a feedback system used for conducting the analysis of cognitive functions to assist caregivers in screening high risk groups with mild cognitive impairment. Three kinds of experiments were performed to evaluate the developed FC-based BG cognitive function assessment system. The experimental results showed that the Pearson correlation coefficient between the system's evaluation outcomes and the traditional Montreal Cognitive Assessment scores was 0.83. The average Technology Acceptance Model 2 score was close to six for 31 elderly subjects. Most subjects considered that the brain games are interesting and the FC human-machine interface is easy to learn and operate. The control group and the cognitive impairment group had statistically significant difference with respect to the accuracy of and the time taken for the brain cognitive function assessment games, including Animal Naming, Color Search, Trail Making Test, Change Blindness, and Forward / Backward Digit Span.

Cortical phase changes measured using 7-T MRI in subjects with subjective cognitive impairment, and their association with cognitive function

Studies have suggested that, in subjects with subjective cognitive impairment (SCI), Alzheimer's disease (AD)-like changes may occur in the brain. Recently, an in vivo study has indicated the potential of ultra-high-field MRI to visualize amyloid-beta (Aβ)-associated changes in the cortex in patients with AD, manifested by a phase shift on T2 *-weighted MRI scans. The main aim of this study was to investigate whether cortical phase shifts on T2 *-weighted images at 7 T in subjects with SCI can be detected, possibly implicating the deposition of Aβ plaques and associated iron. Cognitive tests and T2 *-weighted scans using a 7-T MRI system were performed in 28 patients with AD, 18 subjects with SCI and 27 healthy controls (HCs). Cortical phase shifts were measured. Univariate general linear modeling and linear regression analysis were used to assess the association between diagnosis and cortical phase shift, and between cortical phase shift and the different neuropsychological tests, adjusted for age and gender. The phase shift (mean, 1.19; range, 1.00-1.35) of the entire cortex in AD was higher than in both SCI (mean, 0.85; range, 0.73-0.99; p < 0.001) and HC (mean, 0.94; range, 0.79-1.10; p < 0.001). No AD-like changes, e.g. increased cortical phase shifts, were found in subjects with SCI compared with HCs. In SCI, a significant association was found between memory function (Wechsler Memory Scale, WMS) and cortical phase shift (β = -0.544, p = 0.007). The major finding of this study is that, in subjects with SCI, an increased cortical phase shift measured at high field is associated with a poorer memory performance, although, as a group, subjects with SCI do not show an increased phase shift compared with HCs. This increased cortical phase shift related to memory performance may contribute to the understanding of SCI as it is still unclear whether SCI is a sign of pre-clinical AD. Copyright © 2014 John Wiley & Sons, Ltd.

A Conceptualization of the Utility of Subjective Cognitive Decline in Clinical Trials of Preclinical Alzheimer's Disease

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.

Prospective memory in subjective cognitive decline: a preliminary study on the role of early cognitive marker in dementia

Accumulating evidence shows that subjective cognitive decline (SCD) without impairment on conventional neuropsychological tests may indicate increased risk for Alzheimer disease. Previous studies of mild cognitive impairment have demonstrated the potential role of prospective memory (PM) in the early detection of cognitive decline. We thus aimed to investigate the performance of people with SCD on PM tasks relative to their healthy controls (HCs). Forty-one participants with SCD and demographically matched HCs received regular cognitive testing as well as 2 single-trial naturalistic time-based and event-based PM tasks. Statistical analyses showed that the individuals with SCD performed worse on the time-based PM task, especially on the prospective component, when compared with their HCs. Our findings suggest that PM, especially the time-based one on the prospective component, may be an early cognitive marker of dementia. This implies an underlying difficulty among subjects with SCD in self-initiation that exacerbates their memory difficulties. Further investigation on a large scale is needed.

For a Cognitive Model of Subjective Memory Awareness

The clinical challenge in subjective memory decline (SMD) is to identify which individuals will present memory deficits. Since its early description from Babinsky, who coined the term 'anosognosia' (i.e., the lack of awareness of deficit), the awareness of cognitive impairment is crucial in clinical neuropsychology. We propose a cognitive model in which SMD and anosognosia can be considered two opposite forms of distorted awareness of cognitive performance and can be accounted for within a model in which consciousness of memory performance can vary in a continuum from normal awareness of performance (preserved or impaired) to anosognosia through a disorder of consciousness related to SMD that we call "cognitive dysgnosia", i.e., awareness of normal performance as impaired. This model suggests that the neuropsychological assessment of memory performance should always be coupled with a deep evaluation of awareness of the subject's memory profile, which allow to better identify the disorder of consciousness with or without cognitive impairment. In this line, it seems necessary to develop more sensitive neuropsychological tools in order to discriminate, within the SMD, individuals who are likely to develop clinical Alzheimer's disease from those whose memory decline complaint is not associated with an underlying neurodegenerative pathology.

Serum high-density lipoprotein is associated with better cognitive function in a cross-sectional study of aging women

Purpose/Aim of the study: Poor cardiovascular health, including obesity and altered lipid profiles at mid-life, are linked to increased risk of Alzheimer's disease (AD). The biological mechanisms linking cardiovascular health and cognitive function are unclear though are likely to be multifactorial. This study examined the association between various lipoproteins and cognitive functioning in ageing women.

MATERIALS AND METHODS

We investigated the relationship between readily available biomarkers (i.e. serum lipoprotein) and cognitive decline in domains associated with increased risk of AD (e.g. episodic verbal memory performance and subjective memory complaint). We report cross-sectional data investigating the relationship between serum total cholesterol, triglycerides, high-density lipoprotein (HDL-C) and low-density lipoprotein with verbal memory and learning ability in 130 women with and without memory complaints (n = 71 and 59, respectively) drawn from a study investigating cognitively healthy Western Australians (average age 62.5 years old).

RESULTS

After statistical modelling that controlled for the effects of age, depression and apolipoprotein E genotype, HDL-C was significantly associated with better verbal learning and memory performance, specifically short and long delay-free recalls (F = 3.062; p < .05 and F = 3.2670; p < .05, respectively).

CONCLUSION

Our cross-sectional findings suggest that the positive effect of HDL-C on verbal memory may be present much earlier than previously reported and provide further support for the role of HDL-C in healthy brain ageing. Further exploration of the protective effect of HDL-C on cognitive function in ageing is warranted through follow-up, longitudinal studies.

Effects of Meditation versus Music Listening on Perceived Stress, Mood, Sleep, and Quality of Life in Adults with Early Memory Loss: A Pilot Randomized Controlled Trial

BACKGROUND

Older adults with subjective cognitive decline (SCD) are at increased risk not only for Alzheimer's disease, but for poor mental health, impaired sleep, and diminished quality of life (QOL), which in turn, contribute to further cognitive decline, highlighting the need for early intervention.

OBJECTIVE

In this randomized controlled trial, we assessed the effects of two 12-week relaxation programs, Kirtan Kriya Meditation (KK) and music listening (ML), on perceived stress, sleep, mood, and health-related QOL in older adults with SCD.

METHODS

Sixty community-dwelling older adults with SCD were randomized to a KK or ML program and asked to practice 12 minutes daily for 12 weeks, then at their discretion for the following 3 months. At baseline, 12 weeks, and 26 weeks, perceived stress, mood, psychological well-being, sleep quality, and health-related QOL were measured using well-validated instruments.

RESULTS

Fifty-three participants (88%) completed the 6-month study. Participants in both groups showed significant improvement at 12 weeks in psychological well-being and in multiple domains of mood and sleep quality (p's≤0.05). Relative to ML, those assigned to KK showed greater gains in perceived stress, mood, psychological well-being, and QOL-Mental Health (p's≤0.09). Observed gains were sustained or improved at 6 months, with both groups showing marked and significant improvement in all outcomes. Changes were unrelated to treatment expectancies.

CONCLUSIONS

Findings suggest that practice of a simple meditation or ML program may improve stress, mood, well-being, sleep, and QOL in adults with SCD, with benefits sustained at 6 months and gains that were particularly pronounced in the KK group.

Subjective memory decline predicts greater rates of clinical progression in preclinical Alzheimer's disease

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.

Inclusion of an informant yields strong associations between cognitive complaint and longitudinal cognitive outcomes in non-demented elders

BACKGROUND

The relation between the source of cognitive complaint and objective cognitive performance is not well understood.

OBJECTIVE

Examine self and informant cognitive complaint as predictors of objective cognitive and functional trajectory in non-demented elders.

METHODS

Participants from the National Alzheimer's Coordinating Center had a baseline diagnosis of normal cognition (NC; n = 6133, 72±8 years, 68% female) or mild cognitive impairment (MCI; n = 3010, 74±8 years, 55% female). Four independent groups defined cognitive complaint: no complaint, self-only complaint, informant-only complaint, or mutual complaint (both self and informant complaint). Linear mixed model regression analyses related complaint status (referent was no complaint) to cognitive and functional trajectories, adjusting for age, sex, race, education, and follow-up period.

RESULTS

Among NC participants, mutual complaint related to faster decline in global cognition (p < 0.0001), language (all p-values <0.0001), processing speed (p = 0.0002), and executive functioning (p = 0.0006). Informant-only complaint related to faster decline in global cognition (p = 0.0001) and processing speed (p = 0.0001). Self-only complaint related to greater decline in immediate (p < 0.0001) and delayed (p = 0.0005) episodic memory. In MCI, mutual complaint related to faster decline in global cognition (p < 0.0001), verbal episodic memory (all p-values <0.0001), language (all p-values <0.0001), and processing speed(all p-values <0.0006). Informant-only or self-only complaint associations with cognitive trajectory did not survive correction factor for multiple comparisons.Conclusion: Cognitive complaint appears to have clinical significance, as it is related to declines in objective cognitive performance over time. Mutual complaint was associated with the worst cognitive trajectory in both NC and MCI elders, highlighting the importance of incorporating an informant into evaluation of elders whenever feasible.

Epigenetic age of the pre-frontal cortex is associated with neuritic plaques, amyloid load, and Alzheimer's disease related cognitive functioning

There is an urgent need to develop molecular biomarkers of brain age in order to advance our understanding of age related neurodegeneration. Recently, we developed a highly accurate epigenetic biomarker of tissue age (known as epigenetic clock) which is based on DNA methylation levels. Here we use n=700 dorsolateral prefrontal cortex (DLPFC) samples from Caucasian subjects of the Religious Order Study and the Rush Memory and Aging Project to examine the association between epigenetic age and Alzheimer's disease (AD) related cognitive decline, and AD related neuropathological markers. Epigenetic age acceleration of DLPFC is correlated with several neuropathological measurements including diffuse plaques (r=0.12, p=0.0015), neuritic plaques (r=0.11, p=0.0036), and amyloid load (r=0.091, p=0.016). Further, it is associated with a decline in global cognitive functioning (β=-0.500, p=0.009), episodic memory (β=-0.411, p=0.009) and working memory (β=-0.405, p=0.011) among individuals with AD. The neuropathological markers may mediate the association between epigenetic age and cognitive decline. Genetic complex trait analysis (GCTA) revealed that epigenetic age acceleration is heritable (h2=0.41) and has significant genetic correlations with diffuse plaques (r=0.24, p=0.010) and possibly working memory (r=-0.35, p=0.065). Overall, these results suggest that the epigenetic clock may lend itself as a molecular biomarker of brain age.

APOE effect on Alzheimer's disease biomarkers in older adults with significant memory concern

INTRODUCTION

This study assessed apolipoprotein E (APOE) ε4 carrier status effects on Alzheimer's disease imaging and cerebrospinal fluid (CSF) biomarkers in cognitively normal older adults with significant memory concerns (SMC).

METHODS

Cognitively normal, SMC, and early mild cognitive impairment participants from Alzheimer's Disease Neuroimaging Initiative were divided by APOE ε4 carrier status. Diagnostic and APOE effects were evaluated with emphasis on SMC. Additional analyses in SMC evaluated the effect of the interaction between APOE and [(18)F]Florbetapir amyloid positivity on CSF biomarkers.

RESULTS

SMC ε4+ showed greater amyloid deposition than SMC ε4-, but no hypometabolism or medial temporal lobe (MTL) atrophy. SMC ε4+ showed lower amyloid beta 1-42 and higher tau/p-tau than ε4-, which was most abnormal in APOE ε4+ and cerebral amyloid positive SMC.

DISCUSSION

SMC APOE ε4+ show abnormal changes in amyloid and tau biomarkers, but no hypometabolism or MTL neurodegeneration, reflecting the at-risk nature of the SMC group and the importance of APOE in mediating this risk.

A Mutual Self- and Informant-Report of Cognitive Complaint Correlates with Neuropathological Outcomes in Mild Cognitive Impairment

Background

This study examines whether different sources of cognitive complaint (i.e., self and informant) predict Alzheimer’s disease (AD) neuropathology in elders with mild cognitive impairment (MCI).

Methods

Data were drawn from the National Alzheimer’s Coordinating Center Uniform and Neuropathology Datasets (observational studies) for participants with a clinical diagnosis of MCI and postmortem examination (n = 1843, 74±8 years, 52% female). Cognitive complaint (0.9±0.5 years prior to autopsy) was classified into four mutually exclusive groups: no complaint, self-only, informant-only, or mutual (both self and informant) complaint. Postmortem neuropathological outcomes included amyloid plaques and neurofibrillary tangles. Proportional odds regression related complaint to neuropathology, adjusting for age, sex, race, education, depressed mood, cognition, APOE4 status, and last clinical visit to death interval.

Results

Mutual complaint related to increased likelihood of meeting NIA/Reagan Institute (OR = 6.58, p = 0.004) and Consortium to Establish a Registry for Alzheimer’s Disease criteria (OR = 5.82, p = 0.03), and increased neurofibrillary tangles (OR = 3.70, p = 0.03), neuritic plaques (OR = 3.52, p = 0.03), and diffuse plaques (OR = 4.35, p = 0.02). Informant-only and self-only complaint was not associated with any neuropathological outcome (all p-values>0.12).

Conclusions

In MCI, mutual cognitive complaint relates to AD pathology whereas self-only or informant-only complaint shows no relation to pathology. Findings support cognitive complaint as a marker of unhealthy brain aging and highlight the importance of obtaining informant corroboration to increase confidence of underlying pathological processes.

Development of a subjective cognitive decline questionnaire using item response theory: a pilot study

Introduction

Subjective cognitive decline (SCD) may indicate unhealthy cognitive changes, but no standardized SCD measurement exists. This pilot study aimed to identify reliable SCD questions.

Methods

A total of 112 cognitively normal (NC; 76 ± 8 years; 63% female), 43 mild cognitive impairment (MCI; 77 ± 7 years; 51% female), and 33 diagnostically ambiguous participants (79 ± 9 years; 58% female) were recruited from a research registry and completed 57 self-report SCD questions. Psychometric methods were used for item reduction.

Results

Factor analytic models assessed unidimensionality of the latent trait (SCD); 19 items were removed with extreme response distribution or trait-fit. Item response theory (IRT) provided information about question utility; 17 items with low information were dropped. Post hoc simulation using computerized adaptive test (CAT) modeling selected the most commonly used items (n = 9 of 21 items) that represented the latent trait well (r = 0.94) and differentiated NC from MCI participants (F [1, 146] = 8.9, P = .003).

Discussion

IRT and CAT modeling identified nine reliable SCD items. This pilot study is a first step toward refining SCD assessment in older adults. Replication of these findings and validation with Alzheimer's disease biomarkers will be an important next step for the creation of a SCD screener.

Hypertensive Disorders of Pregnancy Appear Not to Be Associated with Alzheimer's Disease Later in Life

Background

After hypertensive disorders of pregnancy, more subjective cognitive complaints and white matter lesions are reported compared to women after normal pregnancies. Both have a causal relationship with Alzheimer's disease (AD).

Aim

To investigate if women whose pregnancy was complicated by hypertensive disorders have an increased risk of AD.

Methods

A case-control study in women with AD from the Alzheimer Center of the VU University Medical Center Amsterdam and women without AD. Paper and telephone surveys were performed.

Results

The response rate was 85.2%. No relation between women with (n = 104) and without AD (n = 129) reporting pregnancies complicated by hypertensive disorders (p = 0.11) was found. Women with early-onset AD reported hypertensive disorders of pregnancy more often (p = 0.02) compared to women with late-onset AD.

Conclusion

A reported history of hypertensive disorders of pregnancy appears not to be associated with AD later in life.

Subjective Cognitive Decline in Older Adults: An Overview of Self-Report Measures Used Across 19 International Research Studies

Research increasingly suggests that subjective cognitive decline (SCD) in older adults, in the absence of objective cognitive dysfunction or depression, may be a harbinger of non-normative cognitive decline and eventual progression to dementia. Little is known, however, about the key features of self-report measures currently used to assess SCD. The Subjective Cognitive Decline Initiative (SCD-I) Working Group is an international consortium established to develop a conceptual framework and research criteria for SCD (Jessen et al., 2014, Alzheimers Dement 10, 844-852). In the current study we systematically compared cognitive self-report items used by 19 SCD-I Working Group studies, representing 8 countries and 5 languages. We identified 34 self-report measures comprising 640 cognitive self-report items. There was little overlap among measures- approximately 75% of measures were used by only one study. Wide variation existed in response options and item content. Items pertaining to the memory domain predominated, accounting for about 60% of items surveyed, followed by executive function and attention, with 16% and 11% of the items, respectively. Items relating to memory for the names of people and the placement of common objects were represented on the greatest percentage of measures (56% each). Working group members reported that instrument selection decisions were often based on practical considerations beyond the study of SCD specifically, such as availability and brevity of measures. Results document the heterogeneity of approaches across studies to the emerging construct of SCD. We offer preliminary recommendations for instrument selection and future research directions including identifying items and measure formats associated with important clinical outcomes.

Temporal course and pathologic basis of unawareness of memory loss in dementia

OBJECTIVE

To characterize the natural history and neuropathologic basis of unawareness of memory loss in late-life dementia.

METHODS

Analyses are based on 2,092 older persons from 3 longitudinal clinical-pathologic cohort studies who had no memory or cognitive impairment at baseline. Annual evaluations included clinical classification of dementia plus self-rating and performance testing of memory. At death, there was a uniform neuropathologic examination to quantify 7 dementia-related pathologies.

RESULTS

In the full group, memory ratings were modestly correlated with memory performance (intercepts r = 0.26, p < 0.001; slopes r = 0.23, p < 001) and so we regressed each person's memory performance on their memory ratings, and the residuals provided longitudinal indicators of memory awareness. In a subset of 239 persons who developed dementia, episodic memory awareness was stable until a mean of 2.6 years before dementia onset (95% credible interval -2.7, -1.6); thereafter, memory awareness declined rapidly (mean annual change -0.32, 95% credible interval -0.37, -0.28). Older age at baseline was associated with later onset of memory unawareness. In a subset of 385 persons who died and underwent neuropathologic examination, transactive response DNA-binding protein 43 (TDP-43) pathology, tau tangles, and gross cerebral infarcts were related to decline in memory awareness. In the absence of these pathologies, no decline in memory awareness was evident. Results were similar in subgroups with and without dementia.

CONCLUSIONS

Awareness of memory impairment typically begins to decline about 2-3 years before dementia onset and is associated with postmortem evidence of TDP-43 pathology, tangles, and gross cerebral infarcts.

Hippocampal atrophy is associated with subjective memory decline: The PATH Through Life study

OBJECTIVE

To investigate whether subjective memory decline (SMD) in cognitively healthy individuals is associated with hippocampal atrophy.

METHODS

Multiple regression analyses assessing the relationship between hippocampal atrophy over 4 years and SMD at baseline and follow-up in 305 cognitively healthy individuals aged 60-64 years free from dementia, mild cognitive impairment, and other neurological disorders.

RESULTS

SMD at baseline was not a significant predictor of hippocampal atrophy. However, SMD at follow-up was associated with greater hippocampal atrophy. Associations were reduced but remained significant after controlling for anxiety and depression symptomatology.

CONCLUSION

Hippocampal atrophy was associated with incident/persisting SMD and this association was not, or only partly, explained by anxiety and depression symptomatology. These results are consistent with a biological origin to subjective memory decline. SMD should be included in screening and neuropsychological batteries.

A TREM1 variant alters the accumulation of Alzheimer-related amyloid pathology

OBJECTIVE

Genome-wide association studies have linked variants in TREM2 (triggering receptor expressed on myeloid cells 2) and TREML2 with Alzheimer disease (AD) and AD endophenotypes. Here, we pursue a targeted analysis of the TREM locus in relation to cognitive decline and pathological features of AD.

METHODS

Clinical, cognitive, and neuropathological phenotypes were collected in 3 prospective cohorts on aging (n = 3,421 subjects). Our primary analysis was an association with neuritic plaque pathology. To functionally characterize the associated variants, we used flow cytometry to measure TREM1 expression on monocytes.

RESULTS

We provide evidence that an intronic variant, rs6910730(G) , in TREM1, is associated with an increased burden of neuritic plaques (p = 3.7 × 10(-4) ), diffuse plaques (p = 4.1 × 10(-3) ), and Aβ density (p = 2.6 × 10(-3) ) as well as an increased rate of cognitive decline (p = 5.3 × 10(-3) ). A variant upstream of TREM2, rs7759295(C) , is independently associated with an increased tau tangle density (p = 4.9 × 10(-4) ), an increased burden of neurofibrillary tangles (p = 9.1 × 10(-3) ), and an increased rate of cognitive decline (p = 2.3 × 10(-3) ). Finally, a cytometric analysis shows that the TREM1 rs6910730(G) allele is associated with decreased TREM1 expression on the surface of myeloid cells (p = 1.7 × 10(-3) ).

INTERPRETATION

We provide evidence that 2 common variants within the TREM locus are associated with pathological features of AD and aging-related cognitive decline. Our evidence suggests that these variants are likely to be independent of known AD variants and that they may work through an alteration of myeloid cell function.

Biochemical and neuroimaging studies in subjective cognitive decline: progress and perspectives

Neurodegeneration due to Alzheimer's disease (AD) can progress over decades before dementia becomes apparent. Indeed, patients with mild cognitive impairment (MCI) already demonstrate significant lesion loads. In most cases, MCI is preceded by subjective cognitive decline (SCD), which is applied to individuals who have self-reported memory-related complaints and has been associated with a higher risk of future cognitive decline and conversion to dementia. Based on the schema of a well-received model of biomarker dynamics in AD pathogenesis, it has been postulated that SCD symptoms may result from compensatory changes in response to β-amyloid accumulation and neurodegeneration. Although SCD is considered a prodromal stage of MCI, it is also a common manifestation in old age, independent of AD, and the predictive value of SCD for AD pathology remains controversial. Here, we provide a review focused on the contributions of cross-sectional and longitudinal analogical studies of biomarkers and neuroimaging evidence in disentangling under what conditions SCD may be attributable to AD pathology. In conclusion, there is promising evidence indicating that clinicians should be able to differentiate pre-AD SCD based on the presence of pathophysiological biomarkers in cerebrospinal fluid (CSF) and neuroimaging. However, this neuroimaging approach is still at an immature stage without an established rubric of standards. A substantial amount of work remains in terms of replicating recent findings and validating the clinical utility of identifying SCD.

Can Clinical Data Predict Progression to Dementia in Amnestic Mild Cognitive Impairment?

Background:

To determine whether clinical data obtained by history and physical examination can predict eventual progression to dementia in a cohort of elderly people with mild cognitive impairment.

Methods:

A prospective, longitudinal study of a cohort of elderly subjects with amnestic Mild Cognitive Impairment (MCI). Ninety subjects meeting the criteria for amnestic MCI were recruited and followed annually for an average of 3.3 years. Main outcome measure was the development of dementia determined by clinical assessment with confirmatory neuropsychological evaluation.

Results:

Fifty patients (56%) developed dementia on follow-up. They were older, had lower Mini-mental status exam (MMSE) scores and a shorter duration of symptoms at the time of first assessment. Multivariate logistic regression analysis identified age at symptom onset as the only clinical parameter which distinguished the group that deteriorated to dementia from the group that did not. The odds ratio for age was 1.1 (confidence interval 1.04 - 1.18).

Conclusions:

Patients presenting with amnestic MCI insufficient for the diagnosis of dementia are at high risk of developing dementia on follow-up. In our cohort, 56% were diagnosed with dementia over an average period of 5.9 years from symptom onset. The only clinical predictor for the eventual development of dementia was older age at symptom onset. Clinical features alone were insufficient to predict development of dementia.

Subjective cognitive impairment subjects in our clinical practice

Background

The clinical challenge in subjective cognitive impairment (SCI) is to identify which individuals will present cognitive decline. We created a statistical model to determine which variables contribute to SCI and mild cognitive impairment (MCI) versus Alzheimer's disease (AD) diagnoses.

Methods

A total of 993 subjects diagnosed at a memory clinic (2007-2009) were included retrospectively: 433 with SCI, 373 with MCI and 187 with AD. Descriptive statistics were provided. A logistic regression model analyzed the likelihood of SCI and MCI patients being diagnosed with AD, using age, gender, Mini-Mental State Examination score, the ratio of β-amyloid 42 divided by total tau, and phosphorylated tau as independent variables.

Results

The SCI subjects were younger (57.8 ± 8 years) than the MCI (64.2 ± 10.6 years) and AD subjects (70.1 ± 9.7 years). They were more educated, had less medial temporal lobe atrophy (MTA) and frequently normal cerebrospinal fluid biomarkers. Apolipoprotein E4/E4 homozygotes and apolipoprotein E3/E4 heterozygotes were significantly less frequent in the SCI group (6 and 36%) than in the AD group (28 and 51%). Within the regression model, cardiovascular risk factors, confluent white matter lesions, MTA and central atrophy increased the AD likelihood for SCI subjects.

Conclusions

SCI patients form a distinct group. In our model, factors suggesting cardiovascular risk, MTA and central atrophy increased the AD likelihood for SCI subjects.

Subjective cognitive concerns, episodic memory, and the APOE ε4 allele

BACKGROUND

Subjective cognitive concerns may represent a simple method to assess likelihood of memory decline among apolipoprotein E (APOE) ε4 carriers.

METHODS

We examined the relationship of self-reported subjective cognitive concerns, using seven specific cognitive concerns, with memory and memory decline over 6 years among APOE ε4 carriers and non-carriers from the Nurses' Health Study.

RESULTS

In both groups, increasing subjective cognitive concern score predicted worse baseline memory and faster rates of subsequent memory decline, after adjustment for age, education and depression. The relation with baseline memory appeared statistically stronger in APOE ε4 carriers (P-interaction = 0.03). For memory decline, mean differences in slopes of episodic memory (95% CI) for 4 to 7 versus no concern = -0.05 (-0.10, 0.01) standard units in APOE ε4 carriers, and -0.04 (-0.08, -0.01) standard units in non-carriers.

CONCLUSIONS

APOE ε4 carriers with self-assessed cognitive concerns appear to have worse memory, and possibly accelerated memory decline.

An empirically derived composite cognitive test score with improved power to track and evaluate treatments for preclinical Alzheimer's disease

BACKGROUND

There is growing interest in the evaluation of preclinical Alzheimer's disease (AD) treatments. As a result, there is a need to identify a cognitive composite that is sensitive to track preclinical AD decline to be used as a primary endpoint in treatment trials.

METHODS

Longitudinal data from initially cognitively normal, 70- to 85-year-old participants in three cohort studies of aging and dementia from the Rush Alzheimer's Disease Center were examined to empirically define a composite cognitive endpoint that is sensitive to detect and track cognitive decline before the onset of cognitive impairment. The mean-to-standard deviation ratios (MSDRs) of change over time were calculated in a search for the optimal combination of cognitive tests/subtests drawn from the neuropsychological battery in cognitively normal participants who subsequently progressed to clinical stages of AD during 2- and 5-year periods, using data from those who remained unimpaired during the same period to correct for aging and practice effects. Combinations that performed well were then evaluated for representation of relevant cognitive domains, robustness across individual years before diagnosis, and occurrence of selected items within top performing combinations.

RESULTS

The optimal composite cognitive test score comprised seven cognitive tests/subtests with an MSDR = 0.964. By comparison, the most sensitive individual test score was Logical Memory Delayed Recall with an MSDR = 0.64.

CONCLUSIONS

We have identified a composite cognitive test score representing multiple cognitive domains that has improved power compared with the most sensitive single test item to track preclinical AD decline and evaluate preclinical AD treatments. We are confirming the power of the composite in independent cohorts and with other analytical approaches, which may result in refinements, have designated it as the primary endpoint in the Alzheimer's Prevention Initiative's preclinical treatment trials for individuals at high imminent risk for developing symptoms due to late-onset AD.

Self-reported memory complaints: implications from a longitudinal cohort with autopsies

OBJECTIVE

We assessed salience of subjective memory complaints (SMCs) by older individuals as a predictor of subsequent cognitive impairment while accounting for risk factors and eventual neuropathologies.

METHODS

Subjects (n = 531) enrolled while cognitively intact at the University of Kentucky were asked annually if they perceived changes in memory since their last visit. A multistate model estimated when transition to impairment occurred while adjusting for intervening death. Risk factors affecting the timing and probability of an impairment were identified. The association between SMCs and Alzheimer-type neuropathology was assessed from autopsies (n = 243).

RESULTS

SMCs were reported by more than half (55.7%) of the cohort, and were associated with increased risk of impairment (unadjusted odds ratio = 2.8, p < 0.0001). Mild cognitive impairment (dementia) occurred 9.2 (12.1) years after SMC. Multistate modeling showed that SMC reporters with an APOE ε4 allele had double the odds of impairment (adjusted odds ratio = 2.2, p = 0.036). SMC smokers took less time to transition to mild cognitive impairment, while SMC hormone-replaced women took longer to transition directly to dementia. Among participants (n = 176) who died without a diagnosed clinical impairment, SMCs were associated with elevated neuritic amyloid plaques in the neocortex and medial temporal lobe.

CONCLUSION

SMC reporters are at a higher risk of future cognitive impairment and have higher levels of Alzheimer-type brain pathology even when impairment does not occur. As potential harbingers of future cognitive decline, physicians should query and monitor SMCs from their older patients.

Invited commentary: how exposure to air pollution may shape dementia risk, and what epidemiology can say about it

The number of Americans with Alzheimer's disease (AD) dementia is expected to triple by 2050. No effective treatments exist, and prevention research has focused on behaviors and medical conditions, which have been difficult to modify at the population level. Cardiovascular disease epidemiology can inform the search for AD risk factors; exposure to fine particulate matter (PM) air pollution increases cardiovascular risk, pollutant regulations appear to reduce cardiovascular deaths, and vascular pathology influences dementia risk. In this issue of the Journal, Ailshire and Crimmins (Am J Epidemiol. 2014;180(4):359-366) report analyses of data from 14,000 older adults living across the United States, indicating an inverse association between exposure to PM and cognitive function, an outcome related to AD by virtue of the long period of cognitive decline that precedes clinical disease. Their work joins a growing body of data linking PM exposure to AD risk. If these data reflect causality, PM exposure would be 1 of few AD risk factors that are not only widespread, but that also can be modified at the population level using regulatory intervention. Active collaboration between air pollution and dementia epidemiologists will be critical for refining the available evidence and filling fundamental gaps, including the lack of studies on AD itself.

Are depressive symptomatology and self-focused attention associated with subjective memory impairment in older adults?

BACKGROUND

Subjective memory impairment (SMI) refers to conditions in which people complain of memory problems despite intact cognition. The primary purpose of the present study was to examine the roles of self-focused attention and depressive symptomatology in subjective memory complaints.

METHODS

One hundred and eight patients who visited a memory disorder clinic with complaints of memory decline, but who were found on subsequent neuropsychological assessment to have normal cognitive function, were recruited to participate in the study. The severity of subjective memory complaints was measured with the modified Multifactorial Memory Questionnaire. In addition, neuropsychological functions, self-focused attention, and depressive symptomatology were also assessed.

RESULTS

The results showed that the severity of SMI was not significantly correlated with any of the neuropsychological test scores except for the complex figure copy. The severity of SMI, however, was significantly correlated with self-focused attention and depressive symptomatology. Hierarchical regression analysis revealed that self-focused attention and depressive symptomatology significantly contributed to the severity of subjective memory complaints over and above the neuropsychological test performance. The interaction effects between self-focused attention/depressive symptomatology and objective memory performance on the severity of SMI were not significant.

CONCLUSIONS

In conclusion, self-focused attention and depressive symptomatology appear to play important roles in the severity of SMI, even though it is not clear how these factors interact with objective memory performance. Clinical implications as well as limitations of the present study were discussed.

Relationship of subjective cognitive impairment and cognitive impairment no dementia to chronic disease and multimorbidity in a nation-wide twin study

We investigated the relation of subjective cognitive impairment (SCI) and cognitive impairment no dementia (CIND) to common chronic diseases of the elderly and multimorbidity, and assessed the contribution of genetic background and shared familial environment to these associations. Subjects were 11,379 dementia-free twin individuals aged ≥ 65 from the Swedish Twin Registry. SCI was defined as subjective complaint of cognitive change without objective cognitive impairment and CIND was defined according to current criteria. In unmatched, fully-adjusted regression models, mental, musculoskeletal, respiratory, and urological diseases were all significantly associated with increased odds ratios (ORs) of SCI and CIND. Circulatory and gastrointestinal diseases were related to SCI only, while endocrine diseases were associated with CIND. The adjusted ORs of multimorbidity were 2.1 [95% confidence intervals (95% CI): 1.8-2.3] for SCI and 1.5 for CIND (95% CI: 1.3-1.8). A dose-dependent relationship was observed between number of chronic diseases and ORs for SCI but not for CIND. In co-twin control analyses, the chronic diseases-SCI association was largely unchanged. On the other hand, the chronic diseases-CIND association was no longer statistically significant, except for cancer, where an increased OR was observed. In conclusion, chronic morbidity is associated with both SCI and CIND but disease profiles do not always overlap between the two cognitive syndromes. The association is stronger when diseases co-occur, especially for SCI. Genetic and early-life environmental factors may partially explain the association of CIND but not that of SCI with chronic diseases.

Subjective memory complaints, cognitive performance, and psychological factors in healthy older adults

OBJECTIVE

To determine whether subjective memory complaints (SMCs) are associated with performance on objective cognitive measures and psychological factors in healthy, community-dwelling older adults.

METHOD

The cohort was composed of adults, 65 years and older with no clinical evidence of cognitive impairment (n = 125). Participants were administered: CogState computerized neurocognitive battery, Prospective Retrospective Memory Questionnaire, personality and meaning-in-life measures.

RESULTS

SMCs were associated with poorer performance on measures of executive function (p = 0.001). SMCs were also associated with impaired delayed recall (p = 0.006) but this did not remain significant after statistical adjustment for multiple comparisons. SMCs were inversely associated with conscientiousness (p = 0.004) and directly associated with neuroticism (p < 0.001). Higher scores on SMCs were associated with higher perceived stress (p = 0.001), and ineffective coping styles (p = 0.001). Factors contributing to meaning-in-life were associated with fewer SMCs (p < 0.05).

CONCLUSIONS

SMCs may reflect early, subtle cognitive changes and are associated with personality traits and meaning-in-life in healthy, older adults.

Subjective cognitive decline predicts future deterioration in cognitively normal patients with Parkinson's disease

Increasing evidence suggests that subjective cognitive decline (SCD) is a potential predictor of future cognitive decline or dementia. We investigated whether SCD in patients with Parkinson's disease (PD) is a predictor of future cognitive decline. Forty-six cognitively normal patients with PD were selected using comprehensive neuropsychological tests, and classified depending on the presence (PD-SCD(+), n = 25) or absence of SCD (PD-SCD(-), n = 21). After a mean follow-up of 2.4 years, we repeated the cognitive assessments with the same subjects. The clinical characteristics and cognitive performance of the 2 groups did not differ at baseline. At the follow-up assessment, 11 patients in the PD-SCD(+) group (44.0%) and 2 in the PD-SCD(-) group (9.5%) were diagnosed with mild cognitive impairment (MCI), and the PD-SCD(+) patients showed more rapid decline in semantic fluency and visuospatial memory tasks than those in the PD-SCD(-) group. A multivariate logistic regression analysis showed that presence of SCD (odds ratio, 8.378; 95% confidential interval, 1.472-47.683, p = 0.017) and higher Unified PD Rating Scale motor score of 20 or more (odds ratio, 4.539; 95% confidential interval, 1.004-20.528; p = 0.049) were risk factors for incident MCI. Present results demonstrate that SCD in cognitively normal patients with PD is an independent risk factor for incident MCI and acts as a predictor for future cognitive decline.