Subjective cognitive complaints and amyloid burden in cognitively normal older individuals

Glucose 6 phosphate dehydrogenase overexpression rescues the loss of cognition in the double transgenic APP/PS1 mouse model of Alzheimer's disease

Mice models of Alzheimer's disease (APP/PS1) typically experience cognitive decline with age. G6PD overexpressing mice (G6PD-Tg) exhibit better protection from age-associated functional decline including improvements in metabolic and muscle functions as well as reduced frailty compared to their wild-type counterparts. Importantly G6PD-Tg mice show diminished accumulation of DNA oxidation in the brain at different ages in both males and females. To further explore the potential benefits of modulating the G6PD activity in neurodegenerative diseases, triple transgenic mice (3xTg G6PD) were generated, overexpressing APP, PSEN1, and G6PD genes. The cognitive decline characteristic of APP/PS1 mice was prevented in 3xTg G6PD mice, despite similar amyloid-β (Aβ) levels in the hippocampus. This challenges the dominant hypothesis in Alzheimer's disease (AD) etiology and the majority of therapeutic efforts in the field, based on the notion that Aβ is pivotal in cognitive preservation. Notably, the antioxidant properties of G6PD led to a decrease in oxidative stress parameters, such as improved GSH/GSSG and GSH/CysSSG ratios, without major changes in oxidative damage markers. Additionally, metabolic changes in 3xTg G6PD mice increased brain energy status, countering the hypometabolism observed in Alzheimer's models. Remarkably, a higher respiratory exchange ratio suggested increased carbohydrate utilization. The relative failures of Aβ-targeted clinical trials have raised significant skepticism on the amyloid cascade hypothesis and whether the development of Alzheimer's drugs has followed the correct path. Our findings highlight the significance of targeting glucose-metabolizing enzymes rather than solely focusing on Aβ in Alzheimer's research, advocating for a deeper exploration of glucose metabolism's role in cognitive preservation.

Differential neuropsychiatric associations of plasma biomarkers in older adults with major depression and subjective cognitive decline

Older adults with major depressive disorder (MDD) or early cognitive decline during the subjective cognitive decline (SCD) stage may exhibit neuropsychiatric symptoms such as anxiety, depression, and subtle cognitive impairment. The clinicopathological features and biological mechanisms of MDD differ from those of SCD among older adults; these conditions thus require different treatment strategies. This study enrolled 82 participants above 50 years old with normal cognitive levels from the communities to examine biomarker-behavior correlations between MDD (n = 23) and SCD (n = 23) relative to a normal control (NC) group (n = 36). Multidomain assessments were performed for all participants, including immunomagnetic reduction tests to detect plasma beta-amyloid (Aβ), total tau (Tau), phosphorylated tau-181 (p-Tau181), neurofilament light chain, and glial fibrillary acidic protein (GFAP). This study observed that depressive symptoms in MDD were associated with amyloid pathology (plasma Aβ40 vs. HADS-D: R = 0.45, p = 0.031; Aβ42/Aβ40 vs. HADS-D: R = -0.47, p = 0.024), which was not observed in the NC (group difference p < 0.05). Moreover, cognitive decline in MDD was distinguished by a mixed neurodegenerative process involving amyloid (plasma Aβ42 vs. facial memory test: R = 0.48, p = 0.025), tau (Tau/Aβ42 vs. digit symbol substitution test (DSST): R = -0.53, p = 0.01), and astrocytic injury (plasma GFAP vs. Montreal cognitive assessment score: R = -0.44, p = 0.038; plasma GFAP vs. DSST: R = -0.52, p = 0.014), findings that did not apply to the NC (group difference p < 0.05). Moreover, this study revealed different biomarker-behavior correlations between individuals with SCD and the NC. Compared with the NC, cognitive decline in the SCD group might be unrelated to amyloid pathology and instead might be early manifestations of tau pathology. This study underscores the difference in clinicopathological features between MDD and SCD among older adults, which differ from those of the NC. These findings enhance our understanding of the mechanisms underlying MDD and SCD in older individuals.

Herpes zoster and long-term risk of subjective cognitive decline

BACKGROUND

Herpes zoster (HZ), commonly known as "shingles," may contribute to cognitive decline through mechanisms such as neuroinflammation or direct neuronal injury. However, evidence on the longitudinal association between HZ and cognitive decline is conflicting and whether the risk differs by APOE ε4-carrier status has not been studied; prospective cohort studies on the association between HZ vaccination and cognitive decline are also lacking.

METHODS

We included 149,327 participants from three large cohorts-the Nurses' Health Study (NHS), NHSII, and Health Professionals Follow-Up Study (HPFS)-to prospectively examine the association between HZ and subsequent subjective cognitive decline (SCD). Poisson regression was used to estimate the multivariable-adjusted relative risk (MVRR) of a 3-unit increment in SCD score according to years since HZ compared with participants with no history of HZ.

RESULTS

Compared with individuals with no history of HZ, the MVRR (95% CI) of a 3-unit increment in SCD score was significantly and independently higher among individuals with a history of HZ, but the duration of time since HZ when the elevated risk of SCD was statistically significant differed among the cohorts. In NHS, HZ was associated with higher long-term risk of SCD; compared with individuals with no history of HZ, the MVRR (95% CI) of a 3-unit increment in SCD score was 1.14 (1.01, 1.32) for ≥ 13 years since HZ. In NHS II, HZ was associated with higher risk of SCD in both the short-term [MVRR 1.34 (1.18, 1.53) for 1-4 years] and long-term [MVRR 1.20 (1.08, 1.34) for ≥ 13 years since HZ]. In HPFS, an elevated risk of SCD was suggested across all time points. Among the subset of participants with information on APOE ε4, there was a suggestion that the association differed by APOE ε4 carrier status, but the results were not consistent between women and men. Among the subset of women with information on HZ vaccination, there was a suggestion that the long-term risk of SCD may be greater among women who were not vaccinated against HZ.

CONCLUSIONS

Data from three large independent cohorts of women and men showed that HZ was associated with higher long-term risk of SCD, and the risk may differ by APOE ε4-carrier status.

PTSD moderates the association between subjective cognitive decline and Alzheimer's disease biomarkers in older veterans

OBJECTIVES

Post-traumatic stress disorder (PTSD) and subjective cognitive decline (SCD) are independent risk factors for Alzheimer's disease (AD) and dementia, but the association of their interaction on AD biomarkers have yet to be characterized. This study aimed to examine the impact of PTSD on the association between SCD and tau and amyloid positron emission tomography (PET) as well as global cognition in older Veterans.

METHOD

This study included 87 Vietnam-Era Veterans without dementia (42 with PTSD; 45 without PTSD) from the Department of Defense-Alzheimer's Disease Neuroimaging Initiative. All participants had both tau and amyloid PET imaging as well as cognitive testing. SCD was measured using the Everyday Cognition questionnaire.

RESULTS

While SCD was associated with tau PET, amyloid PET, and global cognition, PTSD moderated these associations for tau and amyloid PET levels. Specifically, Veterans without PTSD had a stronger positive relationship between SCD and AD biomarkers when compared to those with PTSD.

CONCLUSION

Higher SCD was associated with greater tau and amyloid burden and worse cognitive performance across the sample, though the tau and amyloid associations were stronger for Veterans without PTSD. Results highlight the potential benefit of comprehensive clinical assessments including consideration of mental health among older Veterans with SCD to understand the underlying cause of the cognitive concerns. Additionally, more work is needed to understand alternative mechanisms driving SCD in older Veterans with PTSD.

Clusters of cognitive performance predict long-term cognitive impairment in elderly patients with subjective memory complaints and healthy controls

INTRODUCTION

Patients with subjective memory complaints (SMC) may include subgroups with different neuropsychological profiles and risks of cognitive impairment.

METHODS

Cluster analysis was performed on two datasets (n: 630 and 734) comprising demographic and neuropsychological data from SMC and healthy controls (HC). Survival analyses were conducted on clusters. Bayesian model averaging assessed the predictive utility of clusters and other biomarkers.

RESULTS

Two clusters with higher and lower than average cognitive performance were detected in SMC and HC. Assignment to the lower performance cluster increased the risk of cognitive impairment in both datasets (hazard ratios: 1.78 and 2.96; Plog-rank: 0.04 and <0.001) and was associated with lower hippocampal volumes and higher tau/amyloid beta 42 ratios in cerebrospinal fluid. The effect of SMC was small and confounded by mood.

DISCUSSION

This study provides evidence of the presence of cognitive clusters that hold biological significance and predictive value for cognitive decline in SMC and HC.

HIGHLIGHTS

Patients with subjective memory complaints include two cognitive clusters. Assignment to the lower performance cluster increases risk of cognitive impairment. This cluster shows a pattern of biomarkers consistent with incipient Alzheimer's disease pathology. The same cognitive cluster structure is found in healthy controls. The effect of memory complaints on risk of cognitive decline is small and confounded.

Associations Between Self and Study Partner Report of Cognitive Decline With Regional Tau in a Multicohort Study

BACKGROUND AND OBJECTIVES

Self-reported cognitive decline is an early behavioral manifestation of Alzheimer disease (AD) at the preclinical stage, often believed to precede concerns reported by a study partner. Previous work shows cross-sectional associations with β-amyloid (Aβ) status and self-reported and study partner-reported cognitive decline, but less is known about their associations with tau deposition, particularly among those with preclinical AD.

METHODS

This cross-sectional study included participants from the Anti-Amyloid Treatment in Asymptomatic AD/Longitudinal Evaluation of Amyloid Risk and Neurodegeneration studies (N = 444) and the Harvard Aging Brain Study and affiliated studies (N = 231), which resulted in a cognitively unimpaired (CU) sample of individuals with both nonelevated (Aβ-) and elevated Aβ (Aβ+). All participants and study partners completed the Cognitive Function Index (CFI). Two regional tau composites were derived by averaging flortaucipir PET uptake in the medial temporal lobe (MTL) and neocortex (NEO). Global Aβ PET was measured in Centiloids (CLs) with Aβ+ >26 CL. We conducted multiple linear regression analyses to test associations between tau PET and CFI, covarying for amyloid, age, sex, education, and cohort. We also controlled for objective cognitive performance, measured using the Preclinical Alzheimer Cognitive Composite (PACC).

RESULTS

Across 675 CU participants (age = 72.3 ± 6.6 years, female = 59%, Aβ+ = 60%), greater tau was associated with greater self-CFI (MTL: β = 0.28 [0.12, 0.44], p < 0.001, and NEO: β = 0.26 [0.09, 0.42], p = 0.002) and study partner CFI (MTL: β = 0.28 [0.14, 0.41], p < 0.001, and NEO: β = 0.31 [0.17, 0.44], p < 0.001). Significant associations between both CFI measures and MTL/NEO tau PET were driven by Aβ+. Continuous Aβ showed an independent effect on CFI in addition to MTL and NEO tau for both self-CFI and study partner CFI. Self-CFI (β = 0.01 [0.001, 0.02], p = 0.03), study partner CFI (β = 0.01 [0.003, 0.02], p = 0.01), and the PACC (β = -0.02 [-0.03, -0.01], p < 0.001) were independently associated with MTL tau, but for NEO tau, PACC (β = -0.02 [-0.03, -0.01], p < 0.001) and study partner report (β = 0.01 [0.004, 0.02], p = 0.002) were associated, but not self-CFI (β = 0.01 [-0.001, 0.02], p = 0.10).

DISCUSSION

Both self-report and study partner report showed associations with tau in addition to Aβ. Additionally, self-report and study partner report were associated with tau above and beyond performance on a neuropsychological composite. Stratification analyses by Aβ status indicate that associations between self-reported and study partner-reported cognitive concerns with regional tau are driven by those at the preclinical stage of AD, suggesting that both are useful to collect on the early AD continuum.

'With or without you': associations between noteworthy events and cognitive complaints across 100 days

OBJECTIVES

Daily noteworthy events have implications for physical and mental health, but less is known about the role daily events have for self-reported cognition and whether the involvement of close social partners differentiates these associations. The current study examined how daily positive and negative noteworthy events relate to subjective memory and attentional difficulties and whether close social partners moderated associations.

METHOD

We used data from a 100-day microlongitudinal web-based study of 104 older adults (Nobservations=7,051; Mage=63.13 years, SDage=7.81, 88.46% Female). Participants reported on exposure to and valence of noteworthy events, involvement of close social partners, and subjective cognitive complaints at the end of each day.

RESULTS

Logistic multilevel models revealed that days with a negative event were associated with increased odds of forgetting something and trouble concentrating whereas days with positive events were associated with decreased odds of trouble concentrating. Close social partner involvement did not moderate within-person associations.

CONCLUSION

Our results suggest that day-to-day events are correlates of cognitive complaints regardless of close social partner involvement in the events. Research should clarify the role of daily positive and negative events in personalized interventions and determine whether this person-centered approach to self-reported cognitive health helps inform diagnostic practices.

White matter alterations and their associations with biomarkers and behavior in subjective cognitive decline individuals: a fixel-based analysis

BACKGROUND

Subjective cognitive decline (SCD) is an early stage of dementia linked to Alzheimer's disease pathology. White matter changes were found in SCD using diffusion tensor imaging, but there are known limitations in voxel-wise tensor-based methods. Fixel-based analysis (FBA) can help understand changes in white matter fibers and how they relate to neurodegenerative proteins and multidomain behavior data in individuals with SCD.

METHODS

Healthy adults with normal cognition were recruited in the Northeastern Taiwan Community Medicine Research Cohort in 2018-2022 and divided into SCD and normal control (NC). Participants underwent evaluations to assess cognitive abilities, mental states, physical activity levels, and susceptibility to fatigue. Neurodegenerative proteins were measured using an immunomagnetic reduction technique. Multi-shell diffusion MRI data were collected and analyzed using whole-brain FBA, comparing results between groups and correlating them with multidomain assessments.

RESULTS

The final enrollment included 33 SCD and 46 NC participants, with no significant differences in age, sex, or education between the groups. SCD had a greater fiber-bundle cross-section than NC (pFWE < 0.05) at bilateral frontal superior longitudinal fasciculus II (SLFII). These white matter changes correlate negatively with plasma Aβ42 level (r = -0.38, p = 0.01) and positively with the AD8 score for subjective cognitive complaints (r = 0.42, p = 0.004) and the Hamilton Anxiety Rating Scale score for the degree of anxiety (Ham-A, r = 0.35, p = 0.019). The dimensional analysis of FBA metrics and blood biomarkers found positive correlations of plasma neurofilament light chain with fiber density at the splenium of corpus callosum (pFWE < 0.05) and with fiber-bundle cross-section at the right thalamus (pFWE < 0.05). Further examination of how SCD grouping interacts between the correlations of FBA metrics and multidomain assessments showed interactions between the fiber density at the corpus callosum with letter-number sequencing cognitive score (pFWE < 0.01) and with fatigue to leisure activities (pFWE < 0.05).

CONCLUSION

Based on FBA, our investigation suggests white matter structural alterations in SCD. The enlargement of SLFII's fiber cross-section is linked to plasma Aβ42 and neuropsychiatric symptoms, which suggests potential early axonal dystrophy associated with Alzheimer's pathology in SCD. The splenium of the corpus callosum is also a critical region of axonal degeneration and cognitive alteration for SCD.

Cerebral Amyloidosis in Individuals with Subjective Cognitive Decline: From Genetic Predisposition to Actual Cerebrospinal Fluid Measurements

The possible relationship between Subjective Cognitive Decline (SCD) and dementia needs further investigation. In the present study, we explored the association between specific biomarkers of Alzheimer's Disease (AD), amyloid-beta 42 (Aβ42) and Tau with the odds of SCD using data from two ongoing studies. In total, 849 cognitively normal (CN) individuals were included in our analyses. Among the participants, 107 had available results regarding cerebrospinal fluid (CSF) Aβ42 and Tau, while 742 had available genetic data to construct polygenic risk scores (PRSs) reflecting their genetic predisposition for CSF Aβ42 and plasma total Tau levels. The associations between AD biomarkers and SCD were tested using logistic regression models adjusted for possible confounders such as age, sex, education, depression, and baseline cognitive test scores. Abnormal values of CSF Aβ42 were related to 2.5-fold higher odds of SCD, while higher polygenic loading for Aβ42 was associated with 1.6-fold higher odds of SCD. CSF Tau, as well as polygenic loading for total Tau, were not associated with SCD. Thus, only cerebral amyloidosis appears to be related to SCD status, either in the form of polygenic risk or actual CSF measurements. The temporal sequence of amyloidosis being followed by tauopathy may partially explain our findings.

Diffusion imaging markers of accelerated aging of the lower cingulum in subjective cognitive decline

Introduction

Alzheimer's Disease (AD) typically starts in the medial temporal lobe, then develops into a neurodegenerative cascade which spreads to other brain regions. People with subjective cognitive decline (SCD) are more likely to develop dementia, especially in the presence of amyloid pathology. Thus, we were interested in the white matter microstructure of the medial temporal lobe in SCD, specifically the lower cingulum bundle that leads into the hippocampus. Diffusion tensor imaging (DTI) has been shown to differentiate SCD participants who will progress to mild cognitive impairment from those who will not. However, the biology underlying these DTI metrics is unclear, and results in the medial temporal lobe have been inconsistent.

Methods

To better characterize the microstructure of this region, we applied DTI to cognitively normal participants in the Cam-CAN database over the age of 55 with cognitive testing and diffusion MRI available (N = 325, 127 SCD). Diffusion MRI was processed to generate regional and voxel-wise diffusion tensor values in bilateral lower cingulum white matter, while T1-weighted MRI was processed to generate regional volume and cortical thickness in the medial temporal lobe white matter, entorhinal cortex, temporal pole, and hippocampus.

Results

SCD participants had thinner cortex in bilateral entorhinal cortex and right temporal pole. No between-group differences were noted for any of the microstructural metrics of the lower cingulum. However, correlations with delayed story recall were significant for all diffusion microstructure metrics in the right lower cingulum in SCD, but not in controls, with a significant interaction effect. Additionally, the SCD group showed an accelerated aging effect in bilateral lower cingulum with MD, AxD, and RD.

Discussion

The diffusion profiles observed in both interaction effects are suggestive of a mixed neuroinflammatory and neurodegenerative pathology. Left entorhinal cortical thinning correlated with decreased FA and increased RD, suggestive of demyelination. However, right entorhinal cortical thinning also correlated with increased AxD, suggestive of a mixed pathology. This may reflect combined pathologies implicated in early AD. DTI was more sensitive than cortical thickness to the associations between SCD, memory, and age. The combined effects of mixed pathology may increase the sensitivity of DTI metrics to variations with age and cognition.

Look who is complaining: Psychological factors predicting subjective cognitive complaints in a large community sample of older adults

Subjective cognitive complaints (SCCs) are not directly related to objective impairments in cognition. This study examines the role of psychological factors in predicting SCCs in the domains of executive functioning, memory, and attention in older adults. A community sample of 1,219 Dutch adults, aged 40 year or older, completed the BRIEF-A, MSEQ, FEDA, NEO-FFI, DASS-21, and a demographic questionnaire. Participants were randomly divided into exploratory (n = 813) and confirmatory samples (n = 406). In the exploratory sample, we analyzed whether personality factors, symptoms of depression and anxiety, perceived stress, and demographics could predict SCCs in the different cognitive domains. For this purpose, a two-step regression approach with bootstrapping was used. To independently validate the results, these analyses were repeated in the confirmatory sample. Concerning executive functioning, complaints regarding the ability to regulate behavior and emotional responses were predicted by lower agreeableness levels and higher levels of neuroticism and perceived stress. Complaints regarding the ability to actively solve problems in different circumstances were predicted by a lower conscientiousness level, higher agreeableness level, and more depressive symptoms. Attentional complaints were predicted by lower levels of conscientiousness and extraversion, together with a higher level of neuroticism. For memory, no significant predictors were consistently found. Psychological factors are of influence on the subjective experience of cognitive complaints. In particular personality factors, perceived stress, and symptoms of depression, seem to predict SCCs in the domains of executive functioning and attention. Clinicians should take these factors into account in older adults who have SCCs.

Effect of visual impairment on subjective cognitive decline in older adults: a cross-sectional study in China

OBJECTIVE

People with visual impairment have more functional limitations associated with subjective cognitive decline (SCD), and those with SCD are extremely susceptible to transitioning to irreversible cognitive impairment. This study aimed to explore if visual impairment is a significant predictor of SCD compared with other socioeconomic and health factors associated with SCD.

DESIGN

Cross-sectional study.

SETTING AND PARTICIPANTS

The investigation aimed to assess the factors influencing SCD among 428 participants aged 60 and above in Zhaoyuan, China.

PRIMARY OUTCOME MEASURES

The primary outcome variable was SCD, measured by the Chinese version of SCD questionnaire. Multiple logistic regression and propensity score matching (PSM) were used to analyse the influence of visual impairment on the subjective cognition of the elderly.32.2% of the elderly were experiencing SCD. Older adults with SCD showed a higher prevalence of visual impairment (72.5%) than the elderly without SCD (58.6%) (P=0.006). Multivariate logistic regression analysis showed that bad self-reported health status, lack of physical exercise and visual impairment were the risk factors for SCD in older adults, while more than 9 years of education was a protective factor. In addition, PSM model showed that after eliminating the dominant biases caused by the individual observable heterogeneity of older adults with and without visual impairment, the risk of SCD in the elderly with visual impairment was increased by 13.6%-14.5% and the difference was statistically significant (P<0.05).

CONCLUSIONS

It was found that older adults experiencing visual impairments are at an elevated risk of developing SCD compared with their counterparts without such impairments. Additionally, visual impairment remains a significant risk factor for SCD in the elderly, even adjusting for potential biases arising from individual observable heterogeneity.

A network approach to subjective cognitive decline: Exploring multivariate relationships in neuropsychological test performance across Alzheimer's disease risk states

Subjective cognitive decline (SCD) is characterized by subjective concerns of cognitive change despite test performance within normal range. Although those with SCD are at higher risk for developing further cognitive decline, we still lack methods using objective cognitive measures that reliably distinguish SCD from cognitively normal aging at the group level. Network analysis may help to address this by modeling cognitive performance as a web of intertwined cognitive abilities, providing insight into the multivariate associations determining cognitive status. Following previous network studies of mild cognitive impairment (MCI) and Alzheimer's dementia (AD), the current study centered upon the novel visualization and analysis of the SCD cognitive network compared to cognitively normal (CN) older adult, MCI, and AD group networks. Cross-sectional neuropsychological data from CIMA-Q and COMPASS-ND cohorts were used to construct Gaussian graphical models for CN (n = 122), SCD (n = 207), MCI (n = 210), and AD (n = 79) groups. Group networks were explored in terms of global network structure, prominent edge weights, and strength centrality indices. CN and SCD group networks were contrasted using the Network Comparison Test. Results indicate that CN and SCD groups did not differ in univariate cognitive performance or global network structure. However, measures of strength centrality, principally in executive functioning and processing speed, showed a CN-SCD-MCI gradient where subtle differences within the SCD network suggest that SCD is an intermediary between CN and MCI stages. Additional results may indicate a distinctiveness of network structure in AD, a reversal in network influence between age and general cognitive status as clinical impairment increases, and potential evidence for cognitive reserve. Together, these results provide evidence that network-specific metrics are sensitive to cognitive performance changes across the dementia risk spectrum and can help to objectively distinguish SCD group cognitive performance from that of the CN group.

Performance on the Latin American version of the Face-Name Associative Memory Exam (LAS-FNAME) distinguishes individuals with Mild Cognitive Impairment from age-matched controls in a sample from Argentina

INTRODUCTION

The Latin American Spanish version of the Face-Name Associative Memory Exam (LAS-FNAME) has shown promise in identifying cognitive changes in those at risk for Alzheimer's disease (AD). However, its applicability for Mild Cognitive Impairment (MCI) detection in the Latin American population remains unexplored. This study aims to analyze the psychometric properties in terms of validity and reliability and diagnostic performance of the LAS-FNAME for the detection of memory disorders in patients with amnestic MCI (aMCI).

MATERIALS AND METHODS

The study included 31 participants with aMCI, diagnosed by a neurologist according to Petersen's criteria, and 19 healthy controls. Inclusion criteria for the aMCI group were to be 60 years of age or older, report cognitive complaints, have a memory test score (Craft Story 21) below a -1.5 z-score and have preserved functioning in activities of daily living. Participants completed LAS-FNAME and a comprehensive neuropsychological assessment.

RESULTS

LAS-FNAME showed the ability to discriminate against healthy controls from patients with aMCI (AUC= 75) in comparison with a gold-standard memory test (AUC = 69.1). LAS-FNAME also showed evidence of concurrent and divergent validity with a standard memory test (RAVLT) (r = 0.58, p < .001) and with an attention task (Digit Span) (r = -0.37, p = .06). Finally, the reliability index was very high (α = 0.88).

DISCUSSION

LAS-FNAME effectively distinguished aMCI patients from healthy controls, suggesting its potential for detecting early cognitive changes in Alzheimer's prodromal stages among Spanish speakers.

Measures of Subjective Memory for People with Epilepsy: A Systematic Review of Measurement Properties

People with epilepsy frequently express concern about the burden of memory problems in their everyday lives. Self-report memory questionnaires may provide valuable insight into individuals' perceptions of their everyday memory performance and changes over time. Yet, despite their potential utility, the measurement properties of self-report memory questionnaires have not been evaluated in epilepsy. This systematic review aimed to provide a critical appraisal of the measurement properties of self-report memory questionnaires for adults with epilepsy. Following protocol registration (PROSPERO CRD42020210967), a systematic search of PubMed, EMBASE, Web of Science, CINAHL, and PsychInfo from database inception until 27 May 2021 was conducted. Eligible studies were published in English-language peer-reviewed journals, recruited adults with epilepsy, and reported on the development or evaluation of the measurement properties of a self-report memory questionnaire. The COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) methodology was used to evaluate each study of a measurement property, and results were qualitatively synthesised. In total, 80 articles and one test manual were located containing 153 studies of measurement properties pertinent to 23 self-report memory questionnaires. Overall, no scale could be recommended outright for the evaluation of subjective memory symptoms in adults with epilepsy. This was due to the near absence of dedicated content validation studies relevant to this population and shortcomings in the methodology and scientific reporting of available studies of structural validity. Recommendations to support the advancement and psychometric validation of self-report memory questionnaires for people with epilepsy are provided.

Genetic Risk for Alzheimer's Disease Alters Perceived Executive Dysfunction in Cognitively Healthy Middle-Aged and Older Adults

Background

Subjective cognitive complaints (SCC) may be an early indicator of future cognitive decline. However, findings comparing SCC and objective cognitive performance have varied, particularly in the memory domain. Even less well established is the relationship between subjective and objective complaints in non-amnestic domains, such as in executive functioning, despite evidence indicating very early changes in these domains. Moreover, particularly early changes in both amnestic and non-amnestic domains are apparent in those carrying the Apolipoprotein-E ɛ4 allele, a primary genetic risk for Alzheimer's disease (AD).

Objective

This study investigated the role of the ɛ4 allele in the consistency between subjective and objective executive functioning in 54 healthy, cognitively intact, middle-aged and older adults.

Methods

Participants (Mage = 64.07, SD = 9.27, range = 48-84; ɛ4+ = 18) completed the Frontal Systems Behavior Scale (FrSBe) Executive Dysfunction Scale (EXECDYS) to measure subjective executive functioning (SEF) and multiple executive functioning tasks, which were condensed into a single factor.

Results

After accounting for age, depression, and anxiety, objective executive functioning performance significantly predicted SEF. Importantly, ɛ4 moderated this effect. Specifically, those carrying the ɛ4 allele had significantly less accurate self-awareness of their executive functioning compared to ɛ4 non-carriers.

Conclusions

Utilizing an approach that integrates self-evaluation of executive functioning with objective neurocognitive assessment may help identify the earliest signs of impending cognitive decline, particularly in those with genetic risk for AD. Such an approach could sensitively determine those most prone to future cognitive decline prior to symptom onset, when interventions could be most effective.

Biomarkers of Alzheimer's Disease and Cerebrovascular Disease in Relation to Depressive Symptomatology in Individuals With Subjective Cognitive Decline

BACKGROUND

Subjective cognitive decline (SCD) has gained recent interest as a potential harbinger of neurodegenerative diseases such as Alzheimer's disease (AD) and cerebrovascular disease (CVD). In addition, SCD can be related to depressive symptomatology. However, the association between AD and CVD biomarkers, depressive symptomatology, and SCD is still unclear. We investigated the association of AD and CVD biomarkers and depressive symptomatology with SCD in individuals with subjective memory complaints (SCD-memory group) and individuals with subjective concentration complaints (SCD-concentration group).

METHODS

We recruited a population-based cohort of 217 individuals (all aged 70 years, 53% female participants, 119 SCD-memory individuals, 23 SCD-concentration individuals, and 89 controls). AD and CVD were assessed through cerebrospinal fluid levels of the Aβ42/40 ratio and phosphorylated tau, and white matter signal abnormalities on magnetic resonance imaging, respectively. Associations between biomarkers, depressive symptomatology, and SCD were tested via logistic regression and correlation analyses.

RESULTS

We found a significant association between depressive symptomatology with SCD-memory and SCD-concentration. Depressive symptomatology was not associated with AD and CVD biomarkers. Both the phosphorylated tau biomarker and depressive symptomatology predicted SCD-memory, and the Aβ42/40 ratio and depressive symptomatology predicted SCD-concentration.

CONCLUSIONS

The role of depressive symptomatology in SCD may differ depending on the stage within the spectrum of preclinical AD (as determined by amyloid-beta and tau positivity), and does not seem to reflect AD pathology. Our findings contribute to the emerging field of subclinical depressive symptomatology in SCD and clarify the association of different types of subjective complaints with distinct syndromic and biomarker profiles.

Symptomatic Clusters Related to Amyloid Positivity in Cognitively Unimpaired Individuals

Background

The NIA-AA Research Framework on Alzheimer's disease (AD) proposes a transitional stage (stage 2) characterized by subtle cognitive decline, subjective cognitive decline (SCD) and mild neurobehavioral symptoms (NPS).

Objective

To identify participant clusters based on stage 2 features and assess their association with amyloid positivity in cognitively unimpaired individuals.

Methods

We included baseline data of N = 338 cognitively unimpaired participants from the DELCODE cohort with data on cerebrospinal fluid biomarkers for AD. Classification into the AD continuum (i.e., amyloid positivity, A+) was based on Aβ42/40 status. Neuropsychological test data were used to assess subtle objective cognitive dysfunction (OBJ), the subjective cognitive decline interview (SCD-I) was used to detect SCD, and the Neuropsychiatric Inventory Questionnaire (NPI-Q) was used to assess NPS. A two-step cluster analysis was carried out and differences in AD biomarkers between clusters were analyzed.

Results

We identified three distinct participant clusters based on presented symptoms. The highest rate of A+ participants (47.6%) was found in a cluster characterized by both OBJ and SCD. A cluster of participants that presented with SCD and NPS (A+:26.6%) and a cluster of participants with overall few symptoms (A+:19.7%) showed amyloid positivity in a range that was not higher than the expected A+ rate for the age group. Across the full sample, participants with a combination of SCD and OBJ in the memory domain showed a lower Aβ42/ptau181 ratio compared to those with neither SCD nor OBJ.

Conclusions

The cluster characterized by participants with OBJ and concomitant SCD was enriched for amyloid pathology.

A Longitudinal Study on Memory Enhancement in Subjective Cognitive Decline Patients: Clinical and Neuroimaging Perspectives

BACKGROUND

Subjective cognitive decline (SCD) refers to the self-reported persistent cognitive decline despite normal objective testing, increasing the risk of dementia compared to cognitively normal individuals.

OBJECTIVE

This study aims to investigate the attributes of SCD patients who demonstrated memory function improvement.

METHODS

In this prospective study of SCD, a total of 120 subjects were enrolled as part of a multicenter cohort study aimed at identifying predictors for the clinical progression to mild cognitive impairment or dementia (CoSCo study). All subjects underwent 18F-florbetaben PET and brain MRI scans at baseline and annual neuropsychological tests. At the 24-month follow-up, we classified SCD patients based on changes in memory function, the z-score of the Seoul verbal learning test delayed recall.

RESULTS

Of the 120 enrolled patients, 107 successfully completed the 24-month follow-up assessment. Among these, 80 patients (74.8%) with SCD exhibited memory function improvements. SCD patients with improved memory function had a lower prevalence of coronary artery disease at baseline and performed better in the trail-making test part B compared to those without improvement. Anatomical and biomarker analysis showed a lower frequency of amyloid PET positivity and larger volumes in the left and right superior parietal lobes in subjects with improved memory function.

CONCLUSIONS

Our prospective study indicates that SCD patients experiencing memory improvement over a 24-month period had a lower amyloid burden, fewer cardiovascular risk factors, and superior executive cognitive function. Identifying these key factors associated with cognitive improvement may assist clinicians in predicting future memory function improvements in SCD patients.

Greater subjective cognitive decline severity is associated with worse memory performance and lower entorhinal cerebral blood flow in healthy older adults

OBJECTIVE

Subjective cognitive decline (SCD) is a potential early risk marker for Alzheimer's disease (AD), but its utility may vary across individuals. We investigated the relationship of SCD severity with memory function and cerebral blood flow (CBF) in areas of the middle temporal lobe (MTL) in a cognitively normal and overall healthy sample of older adults. Exploratory analyses examined if the association of SCD severity with memory and MTL CBF was different in those with lower and higher cardiovascular disease (CVD) risk status.

METHODS

Fifty-two community-dwelling older adults underwent magnetic resonance imaging, neuropsychological testing, and were administered the Everyday Cognition Scale (ECog) to measure SCD. Regression models investigated whether ECog scores were associated with memory performance and MTL CBF, followed by similar exploratory regressions stratified by CVD risk status (i.e., lower vs higher stroke risk).

RESULTS

Higher ECog scores were associated with lower objective memory performance and lower entorhinal cortex CBF after adjusting for demographics and mood. In exploratory stratified analyses, these associations remained significant in the higher stroke risk group only.

CONCLUSIONS

Our preliminary findings suggest that SCD severity is associated with cognition and brain markers of preclinical AD in otherwise healthy older adults with overall low CVD burden and that this relationship may be stronger for individuals with higher stroke risk, although larger studies with more diverse samples are needed to confirm these findings. Our results shed light on individual characteristics that may increase the utility of SCD as an early risk marker of cognitive decline.

Prevalence and risk factors for subjective cognitive decline and the correlation with objective cognition among community-dwelling older adults in China: Results from the Hubei memory and aging cohort study

INTRODUCTION

The prevalence and risk factors for subjective cognitive decline (SCD) and its correlation with objective cognition decline (OCD) among community-dwelling older adults is inconsistent.

METHODS

Older adults underwent neuropsychological and clinical evaluations to reach a consensus on diagnoses.

RESULTS

This study included 7486 adults without mild cognitive impairment and dementia (mean age: 71.35 years [standard deviation = 5.40]). The sex-, age-, and residence-adjusted SCD prevalence was 58.33% overall (95% confidence interval: 58.29% to 58.37%), with higher rates of 61.25% and 59.87% in rural and female subgroups, respectively. SCD global and OCD language, SCD memory and OCD global, SCD and OCD memory, and SCD and OCD language were negatively correlated in fully adjusted models. Seven health and lifestyle factors were associated with an increased risk for SCD.

DISCUSSION

SCD affected 58.33% of older adults and may indicate concurrent OCD, which should prompt the initiation of preventative intervention for dementia.

HIGHLIGHTS

SCD affects 58.33% of older adults in China. SCD may indicate concurrent objective cognitive decline. Difficulty finding words and memory impairments may indicate a risk for AD. The presence of SCD may prompt preventative treatment initiation of MCI or dementia. Social network factors may be initial targets for the early prevention of SCD.

Cognitive trajectories: exploring the predictive role of subjective cognitive decline and awareness of age-related changes for cognitive functioning

Background

We investigated whether aspects of subjective cognitive aging, including awareness of age-related gains and losses in cognition (AARC-gains, AARC-losses) and subjective cognitive decline (SCD), predict change in objective cognitive function as measured by verbal reasoning (VR) and working memory (WM).

Methods

We used longitudinal data for 3,299 cognitively healthy UK residents aged 65+. We used data on AARC and SCD assessed in 2019, and cognitive tasks assessed in 2019, 2020, and 2021. We used latent growth curve modeling, latent class growth analysis, and growth mixture modeling.

Results

For VR, multiple growth trajectories were not evident. Mean VR at baseline was 37.45; this remained stable over time. Higher AARC-gains in cognition (mean intercept = -0.23; 95%CI: -0.31; -0.16), higher AARC-losses in cognition (mean intercept = -0.37; 95%CI: -0.46; -0.28), and lower SCD (mean intercept = 2.92; 95%CI: 2.58; 3.58) were associated with poorer VR at baseline. A three-class growth mixture model-class varying best represented trajectories of WM. In Class 1 (N = 182) mean WM at baseline was 31.20; this decreased by 2.48 points each year. In Class 2 (N = 119) mean WM at baseline was 23.12; this increased by 3.28 points each year. In Class 3 (N = 2,998) mean WM at baseline was 30.11; and it remained stable. Higher AARC-gains (Odds Ratio = 1.08; 95%CI: 1.03; 1.14) and AARC-losses (Odds Ratio = 1.10; 95%CI: 1.04; 1.16) in cognition predicted greater likelihood of being in Class 2 than Class 3.

Conclusion

Although both higher AARC-gains and AARC-losses indicate poorer concurrent cognition, higher AARC-gains may be a resource that facilitates future cognitive improvement.

Operationalizing selection criteria for clinical trials in Alzheimer's disease: Biomarker and clinical considerations

Alzheimer's disease (AD) staging criteria lack standardized, empirical description. Well-defined AD staging criteria are an important consideration in protocol design, influencing a more standardized inclusion/exclusion criteria and defining what constitutes meaningful differentiation among the stages. However, many trials are being designed on the basis of biomarker features and the two need to be coordinated. The Alzheimer's Association Research Roundtable (AARR) Spring 2021 meeting discussed the implementation of preclinical AD staging criteria, and provided recommendations for how they may best be incorporated into clinical trials research. Discussion also included what currently available tools for global clinical trials may best define populations in preclinical AD trials, and if are we able to differentiate preclinical from clinical stages of the disease. Well-defined AD staging criteria are key to improving early detection, diagnostics, clinical trial enrollment, and identifying statistically significant clinical changes, and researchers discussed how emerging blood biomarkers may help with more efficient screening in preclinical stages.

The "when" matters: Evidence from memory markers in the clinical continuum of Alzheimer's disease

OBJECTIVE

Cognitive assessment able to detect impairments in the early neuropathological stages of Alzheimer's disease (AD) is urgently needed. The visual short-term memory binding task (VSTMBT) and the Free and Cued Selective Reminding Test (FCSRT) have been recommended by the neurodegenerative disease working group as promising tests to aid in the early detection of AD. In this study, we investigated their complementary value across the clinical stages of the AD continuum.

METHOD

One hundred and seventeen older adults with subjective cognitive complaint (SCC), 79 with mild cognitive impairment (MCI), 31 patients with AD dementia (ADD), and 37 cognitively unimpaired (CU) subjects, underwent assessment with the VSTMBT and the picture version of the Spanish FCSRT.

RESULTS

After controlling for multiple comparisons, significant differences were found across groups. The VSTMBT was the only test that "marginally" differentiated between CU and SCC (d = 0.47, p = .052). Moreover, whereas the FCSRT showed a gradient (CU = SCC) > MCI > ADD, the VSTMBT gradient was CU > SCC > (MCI = ADD) suggesting that conjunctive binding deficits assessed by the latter may be sensitive to the very early stages of the disease.

CONCLUSIONS

Our results suggest that the VSTMBT and the FCSRT are sensitive to the clinical continuum of AD. Whereas the former detects changes in the early prodromal stages, the latter is more sensitive to the advanced prodromal stages of AD. These novel tests can aid in the early detection, monitor disease progression and response to treatment, and thus support drug development programs. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Subjective cognitive decline across ethnoracial groups in the A4 study

INTRODUCTION

The associations between subjective cognitive decline (SCD), cognition, and amyloid were explored across diverse participants in the A4 study.

METHODS

Five thousand one hundred and fifty-one non-Hispanic White, 262 non-Hispanic Black, 179 Hispanic-White, and 225 Asian participants completed the Preclinical Alzheimer Cognitive Composite (PACC), self- and study partner-reported Cognitive Function Index (CFI). A subsample underwent amyloid positron emission tomography (18 F-florbetapir) (N = 4384). We examined self-reported CFI, PACC, amyloid, and study partner-reported CFI by ethnoracial group.

RESULTS

The associations between PACC-CFI and amyloid-CFI were moderated by race. The relationships were weaker or non-significant in non-Hispanic Black and Hispanic White groups. Depression and anxiety scores were stronger predictors of CFI in these groups. Despite group differences in the types of study partners, self- and study partner-CFI were congruent across groups.

DISCUSSION

SCD may not uniformly relate to cognition or AD biomarkers in different ethnoracial groups. Nonetheless, self- and study partner-SCD were congruent despite differences in study partner type. Highlights Association between SCD and objective cognition was moderated by ethnoracial group. Association between SCD and amyloid was moderated by ethnoracial group. Depression and anxiety were stronger predictors of SCD in Black and Hispanic groups. Study-partner and self-reported SCD are congruent across groups. Study-partner report was consistent despite difference in study partner types.

The impact of technology-based compensatory behaviors on subjective cognitive decline in older adults with a family history of dementia

The current study examined whether greater use of technology to help with daily tasks is associated with less subjective cognitive decline (SCD), especially in individuals with a family history of Alzheimer's disease (AD). Individuals over the age of 50 (n = 102; age range 50-85) completed surveys about their digital and analog approaches to daily tasks, physical activity, and SCD. Participants with and without family histories of AD were matched on age, education, sex, and family history of AD using the R package MatchIt. There was no main effect of technology-based behavioral strategies on SCD (p = 0.259). However, a family history of AD moderated the association between technology use and SCD even when controlling for another protective lifestyle factor, physical activity. In individuals with a family history of AD, more reliance on technology-based behavioral strategies was associated with less SCD (p = 0.018), but this relationship was not significant in individuals without family history of AD (p = 0.511). Our findings suggest that technology-based behavioral strategies are associated with less SCD in individuals with a family history of AD, independent of another protective lifestyle factor. Future recommendations provided by healthcare providers to address SCD in cognitively unimpaired older adults might include focusing on technological assistance.

PRedicting the EVolution of SubjectIvE Cognitive Decline to Alzheimer's Disease With machine learning: the PREVIEW study protocol

BACKGROUND

As disease-modifying therapies (DMTs) for Alzheimer's disease (AD) are becoming a reality, there is an urgent need to select cost-effective tools that can accurately identify patients in the earliest stages of the disease. Subjective Cognitive Decline (SCD) is a condition in which individuals complain of cognitive decline with normal performances on neuropsychological evaluation. Many studies demonstrated a higher prevalence of Alzheimer's pathology in patients diagnosed with SCD as compared to the general population. Consequently, SCD was suggested as an early symptomatic phase of AD. We will describe the study protocol of a prospective cohort study (PREVIEW) that aim to identify features derived from easily accessible, cost-effective and non-invasive assessment to accurately detect SCD patients who will progress to AD dementia.

METHODS

We will include patients who self-referred to our memory clinic and are diagnosed with SCD. Participants will undergo: clinical, neurologic and neuropsychological examination, estimation of cognitive reserve and depression, evaluation of personality traits, APOE and BDNF genotyping, electroencephalography and event-related potential recording, lumbar puncture for measurement of Aβ42, t-tau, and p-tau concentration and Aβ42/Aβ40 ratio. Recruited patients will have follow-up neuropsychological examinations every two years. Collected data will be used to train a machine learning algorithm to define the risk of being carriers of AD and progress to dementia in patients with SCD.

DISCUSSION

This is the first study to investigate the application of machine learning to predict AD in patients with SCD. Since all the features we will consider can be derived from non-invasive and easily accessible assessments, our expected results may provide evidence for defining cost-effective and globally scalable tools to estimate the risk of AD and address the needs of patients with memory complaints. In the era of DMTs, this will have crucial implications for the early identification of patients suitable for treatment in the initial stages of AD.

TRIAL REGISTRATION NUMBER (TRN)

NCT05569083.

The QPLEX™ Plus Assay Kit for the Early Clinical Diagnosis of Alzheimer's Disease

We recently developed a multiplex diagnostic kit, QPLEX™ Alz plus assay kit, which captures amyloid-β1-40, galectin-3 binding protein, angiotensin-converting enzyme, and periostin simultaneously using microliters of peripheral blood and utilizes an optimized algorithm for screening Alzheimer's disease (AD) by correlating with cerebral amyloid deposition. Owing to the demand for early AD detection, we investigate the potential of our kit for the early clinical diagnosis of AD. A total of 1395 participants were recruited, and their blood samples were analyzed with the QPLEX™ kit. The average of QPLEX™ algorithm values in each group increased gradually in the order of the clinical progression continuum of AD: cognitively normal (0.382 ± 0.150), subjective cognitive decline (0.452 ± 0.130), mild cognitive impairment (0.484 ± 0.129), and AD (0.513 ± 0.136). The algorithm values between each group showed statistically significant differences among groups divided by Mini-Mental State Examination and Clinical Dementia Rating. The QPLEX™ algorithm values could be used to distinguish the clinical continuum of AD or cognitive function. Because blood-based diagnosis is more accessible, convenient, and cost- and time-effective than cerebral spinal fluid or positron emission tomography imaging-based diagnosis, the QPLEX™ kit can potentially be used for health checkups and the early clinical diagnosis of AD.

Linking self-perceived cognitive functioning questionnaires using item response theory: The subjective cognitive decline initiative

OBJECTIVE

Self-perceived cognitive functioning, considered highly relevant in the context of aging and dementia, is assessed in numerous ways-hindering the comparison of findings across studies and settings. Therefore, the present study aimed to link item-level self-report questionnaire data from international aging studies.

METHOD

We harmonized secondary data from 24 studies and 40 different questionnaires with item response theory (IRT) techniques using a graded response model with a Bayesian estimator. We compared item information curves to identify items with high measurement precision at different levels of the self-perceived cognitive functioning latent trait. Data from 53,030 neuropsychologically intact older adults were included, from 13 English language and 11 non-English (or mixed) language studies.

RESULTS

We successfully linked all questionnaires and demonstrated that a single-factor structure was reasonable for the latent trait. Items that made the greatest contribution to measurement precision (i.e., "top items") assessed general and specific memory problems and aspects of executive functioning, attention, language, calculation, and visuospatial skills. These top items originated from distinct questionnaires and varied in format, range, time frames, response options, and whether they captured ability and/or change.

CONCLUSIONS

This was the first study to calibrate self-perceived cognitive functioning data of geographically diverse older adults. The resulting item scores are on the same metric, facilitating joint or pooled analyses across international studies. Results may lead to the development of new self-perceived cognitive functioning questionnaires guided by psychometric properties, content, and other important features of items in our item bank. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Measurement of Dimensions of Self-awareness of Memory Function and Their Association With Clinical Progression in Cognitively Normal Older Adults

IMPORTANCE

The ability to separately explore 2 dimensions of self-awareness of memory function-increased and decreased awareness-in cognitively normal older adults provides an important opportunity to understand subtle changes in either direction in relation to risk of Alzheimer disease.

OBJECTIVE

To investigate the association of a novel measure for self-awareness of memory function with future clinical progression in individuals who were cognitively normal at baseline.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study used data from the Alzheimer's Disease Neuroimaging Initiative, a multicenter study. Participants were older adults who were cognitively normal (ie, Clinical Dementia Rating [CDR] global score of 0) at baseline and had at least 2 years of follow-up. Data were collected from June 2010 to December 2021 and pulled from the University of Southern California Laboratory of Neuro Imaging database on January 18, 2022. Clinical progression was defined as the first instance of 2 consecutive follow-up CDR scale global scores of 0.5 or greater.

MAIN OUTCOMES AND MEASURES

A traditional awareness score was measured by calculating the mean discrepancy between the participant and their study partner's scores on the Everyday Cognition questionnaire. An unawareness or heightened awareness subscore was generated by capping item-level positive or negative differences at zero before averaging. The main outcome-risk of future clinical progression-was analyzed for each baseline awareness measure using Cox regression analysis. Longitudinal trajectories of each measure were additionally compared using linear mixed-effects models.

RESULTS

The 436-person sample included 232 (53.2%) female participants, with a mean (SD) age of 74.5 (6.7) years; 25 participants (5.7%) were Black, 14 (3.2%) Hispanic, and 398 (91.3%) White; and 91 participants (20.9%) clinically progressed over their period of observation. Survival analyses showed that a 1-point improvement on the unawareness subscore was associated with an 84% reduction in progression hazard (hazard ratio, 0.16 [95% CI, 0.07-0.35]; P < .001), or equivalently, a 1-point decrease was associated with a 540% increase in progression hazard (95% CI, 183% to 1347%), with no significant results for the heightened awareness or traditional scores.

CONCLUSIONS AND RELEVANCE

In this cohort study of 436 cognitively normal older adults, unawareness, rather than heightened awareness, of memory decline was strongly associated with future clinical progression, providing further support that discordant self- and informant-reported cognitive decline may provide important information to practitioners.

Relation of modifiable lifestyle and mood factors to cognitive concerns among participants and their study partners in the A4 screen data

Introduction

Subjective cognitive decline (SCD) has been associated with elevated amyloid levels and increased risk of future cognitive decline, as well as modifiable variables, including depression, anxiety, and physical inactivity. Participants generally endorse greater and earlier concerns than their close family and friends (study partners [SPs]), which may reflect subtle changes at the earliest stages of disease among participants with underlying neurodegenerative processes. However, many individuals with subjective concerns are not at risk of Alzheimer's disease (AD) pathology, suggesting that additional factors, such as lifestyle habits, may be contributory.

Methods

We examined the relation between SCD, amyloid status, lifestyle habits (exercise, sleep), mood/anxiety, and demographic variables among 4481 cognitively unimpaired older adults who are being screened for a multi-site secondary prevention trial (A4 screen data; mean ±SD: age = 71.3 ±4.7, education = 16.6 ±2.8, 59% women, 96% non-Hispanic or Latino, 92% White].

Results

On the Cognitive Function Index (CFI) participants endorsed higher concerns compared to SPs. Participant concerns were associated with older age, positive amyloid status, worse mood/anxiety, lower education, and lower exercise, whereas SP concerns were associated with older participant age, male gender of participant, positive amyloid status of participant, and worse participant-reported mood/anxiety.

Discussion

Findings suggest that modifiable/lifestyle factors (e.g., exercise, education) may be associated with participant concerns among cognitively unimpaired individuals and highlight the importance of further examining how modifiable factors impact participant- and SP-reported concerns, which may inform trial recruitment and clinical interventions.

A Pilot Study on Cerebral Blood Flow and Mini-Mental State Examination to Predict Amyloid Deposition in Preclinical Alzheimer's Disease

Background

Earlier differential diagnosis of dementia remains a major challenge. Although amyloid deposition by positron emission tomography is an emerging standard for the diagnosis of Alzheimer's disease, it is too expensive for routine use in clinical settings. We conducted a pilot study on the potential usefulness of single-photon emission computed tomography and the Mini-Mental State Examination to predict amyloid positron emission tomography positivity in preclinical Alzheimer's disease.

Methods

Eighteen subjects, including 11 with mild cognitive impairment and 7 with subjective cognitive decline, underwent 18F-florbetapir positron emission tomography, 99mTc-ethylcysteinate dimer cerebral perfusion single-photon emission computed tomography, and the Mini-Mental State Examination. For the assessment of amyloid deposition, visual judgment as a qualitative method and a semiautomatic software analysis as a quantitative method were used.

Results

Six subjects were judged as amyloid positive, including 4 mild cognitive impairment and 2 subjective cognitive decline subjects. Compared to the amyloid positron emission tomography-negative group, this group showed a statistically significant difference in the Mini-Mental State Examination recall score [2 (1 : 3) vs. 3 (2 : 3), P = .041] and single-photon emission computed tomography findings from the amyloid-negative group. In the mild cognitive impairment subgroup, correlations were found between amyloid deposition and single-photon emission computed tomography indicators, while in the subjective cognitive decline subgroup, only the Mini-Mental State Examination recall score correlated with amyloid deposition.

Conclusion

The Mini-Mental State Examination recall score and single-photon emission computed tomography indicators may be worthwhile for further evaluation as predictors of amyloid deposition in the preclinical stage.

Longitudinal association between subjective and objective memory in older adults: a study with the Virginia Cognitive Aging Project sample

Using the bivariate dual change score approach, the present study investigated the directionality of the SMC-OMP association in a sample of healthy older adults (N = 2,057) from the Virginia Cognitive Aging Project. The sample was assessed throughout 10 years, five time points, and the impact of education, depressive symptoms, and low-memory functioning was tested. The Memory Functioning Questionnaire was used to assess SMC. There was a lack of longitudinal association with no significant coupling effects found between subjective and objective memory. After including depressive symptoms as a covariate, Frequency of Forgetting significantly predicted subsequent negative changes in OMP . A similar result was found for the low-memory functioning group after the inclusion of depression, with the frequency of memory complaints predicting subsequent memory decline . Our results do not support a predictive value of SMC without accounting for the influence of depressive symptoms and low-memory functioning.

An attention-based deep learning approach for the classification of subjective cognitive decline and mild cognitive impairment using resting-state EEG

Objective. This study aims to design and implement the first deep learning (DL) model to classify subjects in the prodromic states of Alzheimer's disease (AD) based on resting-state electroencephalographic (EEG) signals.Approach. EEG recordings of 17 healthy controls (HCs), 56 subjective cognitive decline (SCD) and 45 mild cognitive impairment (MCI) subjects were acquired at resting state. After preprocessing, we selected sections corresponding to eyes-closed condition. Five different datasets were created by extracting delta, theta, alpha, beta and delta-to-theta frequency bands using bandpass filters. To classify SCDvsMCI and HCvsSCDvsMCI, we propose a framework based on the transformer architecture, which uses multi-head attention to focus on the most relevant parts of the input signals. We trained and validated the model on each dataset with a leave-one-subject-out cross-validation approach, splitting the signals into 10 s epochs. Subjects were assigned to the same class as the majority of their epochs. Classification performances of the transformer were assessed for both epochs and subjects and compared with other DL models.Main results. Results showed that the delta dataset allowed our model to achieve the best performances for the discrimination of SCD and MCI, reaching an Area Under the ROC Curve (AUC) of 0.807, while the highest results for the HCvsSCDvsMCI classification were obtained on alpha and theta with a micro-AUC higher than 0.74.Significance. We demonstrated that DL approaches can support the adoption of non-invasive and economic techniques as EEG to stratify patients in the clinical population at risk for AD. This result was achieved since the attention mechanism was able to learn temporal dependencies of the signal, focusing on the most discriminative patterns, achieving state-of-the-art results by using a deep model of reduced complexity. Our results were consistent with clinical evidence that changes in brain activity are progressive when considering early stages of AD.

Direct and Indirect Predictors of Medication Adherence With Bipolar Disorder: Path Analysis

BACKGROUND

Despite the efficacy of treatment and severity of symptoms, medication adherence by many with bipolar disorder (BD) is variable at best. This poses a significant challenge for BD care management.

OBJECTIVE

For this study, we set out to identify psychosocial and psychiatric predictors of medication adherence with BD.

METHODS

Using microtargeted social media advertising, we recruited an international sample of young and older adults with BD living in North America (Canada and the United States), Western Europe (eg, United Kingdom and Ireland), Australia and New Zealand (N=92). On average, participants were 55.35 (SD 9.65; range 22-73) years of age, had been diagnosed with BD 14.25 (SD 11.14; range 1-46) years ago, and were currently prescribed 2.40 (SD 1.28; range 0-6) psychotropic medications. Participants completed questionnaires online including the Morisky Medication Adherence Scale.

RESULTS

Medication adherence did not significantly differ across BD subtypes, country of residence, or prescription of lithium versus other mood stabilizers (eg, anticonvulsants). Path analyses indicate that alcohol misuse and subjective or perceived cognitive failures are direct predictors of medication adherence. BD symptoms, psychological well-being, and the number of comorbid psychiatric conditions emerged as indirect predictors of medication adherence via perceived cognitive failures.

CONCLUSIONS

Alcohol misuse did not predict perceived cognitive failures. Nor did age predict medication adherence or cognitive failures. This is noteworthy given the 51-year age range of participants. That is, persons in their 20s with BD reported similar levels of medication adherence and perceived cognitive failures as those in their 60s. This suggests that perceived cognitive loss is a facet of adult life with BD, in contrast to the assumption that accelerated cognitive aging with BD begins in midlife.

Characteristics of Subjective Cognitive Decline Associated with Alzheimer's Disease Amyloid Pathology: Findings from The CABLE Study

BACKGROUND

Subjective cognitive decline (SCD) is considered as a preclinical hallmark of Alzheimer's disease (AD). However, the characteristics of SCD associated with amyloid pathology remain unclear.

OBJECTIVE

We aimed to explore the associations between SCD characteristics with amyloid pathology.

METHODS

Using logistic regression analyses, we analyzed the associations between cerebrospinal fluid (CSF) amyloid pathology with AD risk factors, SCD-specific characteristics (onset of SCD within the last five years, age at onset ≥60 years, feelings of worse performance, informant confirmation of complaints, worries, other domains of cognition complaints), as well as subthreshold depressive and anxiety symptoms among individuals with SCD.

RESULTS

A total of 535 SCD individuals with available CSF Aβ 42 information from the Chinese Alzheimer's Biomarker and LifestylE (CABLE) study (mean age of 63.5 years, range 40 to 88 years; 47.10% female) were enrolled. The characteristics of informant confirmation of complaints (OR, 95% CI = 2.00, 1.19-3.36), subthreshold depressive symptoms (OR, 95% CI = 2.31, 1.05-5.09), and subthreshold anxiety symptoms (OR, 95% CI = 2.22, 1.09-4.51) were found to be significantly associated with pathological amyloid in multivariate analyses when adjusting for age, sex, education, and APOE ɛ4. Besides, age and females were observed risks for amyloid pathology in subscale analyses. Nonetheless, we did not find any associations of other SCD-specific characteristics with amyloid pathology in this study.

CONCLUSION

Our study suggested that informant confirmed complaints and subthreshold psychiatric symptoms might be critical for discriminating AD-related SCD from non-AD related SCD.

Neural correlates of subjective cognitive decline in adults at high risk for Alzheimer's disease

Introduction

Recently, interest has emerged in subjective cognitive decline (SCD) as a potential precursor to Alzheimer's disease (AD) dementia. Whether individuals with SCD harbor brain alterations in midlife, when AD-related pathology begins, is yet to be elucidated. Furthermore, the role of apolipoprotein ε4 (APOE ε4) allele, a robust AD risk factor, in the relationship between SCD and brain alterations is unknown. We examined whether APOE genotype modulates the association of SCD with brain measures in individuals at high AD risk.

Methods

Middle-aged adults with parental history of AD dementia underwent magnetic resonance imaging (MRI) and the Memory Functioning Questionnaire. Regression analysis tested the extent to which SCD was associated with activation during an functional MRI (fMRI) working-memory task, and white-matter microstructure. APOE ε4 genotype was tested as a moderator.

Results

Among APOE ε4 carriers, but not among non-carriers, SCD was associated with higher activation in the anterior cingulate (p = 0.003), inferior, middle, and superior frontal cortices (p = 0.041, p = 0.048, p = 0.037, respectively); and with lower fractional anisotropy in the uncinate fasciculus (p = 0.002), adjusting for age, sex, and education.

Conclusion

In middle aged, cognitively normal individuals at high AD risk, higher SCD was associated with greater brain alterations possibly reflecting incipient AD pathology. When accompanied by a family history of AD and an APOE ε4 allele, SCD may have important clinical value, allowing a window for early intervention and for participants' stratification in AD prevention clinical trials.

Lower visual processing speed relates to greater subjective cognitive complaints in community-dwelling healthy older adults

Introduction

Subjective cognitive complaints in older age may reflect subtle objective impairments in basic cognitive functions that might foreshadow broader cognitive problems. Such cognitive functions, however, are not captured by standard neuropsychological testing. Visual processing speed is a basic visual attention function that underlies the performance of cognitive tasks relying on visual stimuli. Here, we test the hypothesis that lower visual processing speed correlates with greater subjective cognitive complaints in healthy older adults from the community.

Methods

To do so, we assessed a sample of 30 healthy, cognitively normal older adults (73.07 ± 7.73 years old; range: 60-82; 15 females) with respect to individual subjective cognitive complaints and visual processing speed. We quantified the degree of subjective cognitive complaints with two widely-used questionnaires: the Memory Functioning Questionnaire and the Everyday Cognition. We used verbal report tasks and the theory of visual attention to estimate a visual processing speed parameter independently from motor speed and other visual attention parameters, i.e., visual threshold, visual short-term memory storage capacity, top-down control, and spatial weighting.

Results

We found that lower visual processing speed correlated with greater subjective complaints and that this relationship was not explained by age, education, or depressive symptoms. The association with subjective cognitive complaints was specific to visual processing speed, as it was not observed for other visual attention parameters.

Discussion

These results indicate that subjective cognitive complaints reflect a reduction in visual processing speed in healthy older adults. Together, our results suggest that the combined assessment of subjective cognitive complaints and visual processing speed has the potential to identify individuals at risk for cognitive impairment before the standard tests show any abnormal results.

Implications of refrigerator management on subjective memory complaints among Japanese community-dwelling older adults

AIM

Older adults with subjective memory complaints (SMC) may experience very minor difficulties in daily activities. Although caregivers and occupational therapists who support community-dwelling older adults are aware of the existence of characteristic behaviours related to refrigerator management, no specific studies have been conducted. This study aimed to examine the implications of refrigerator management for older adults with SMC.

METHODS

A self-administered questionnaire was sent to 3000 randomly selected members of Consumer's Co-operative Kagoshima. Of the returned responses, a total of 282 older adults were analyzed. Analyzed subjects were divided into two groups: SMC (+) group (n = 74) and SMC (-) group (n = 192). A questionnaire was created by four occupational therapists and used to assess the characteristics of analyzed subjects and their abilities to manage the refrigerator. The observation list for early signs of dementia was also utilised. A multiple logistic analysis was performed to examine the association between SMC and refrigerator management.

RESULTS

The SMC (+) group had a significantly higher number of refrigerator management errors than the SMC (-) group (P = 0.008). The SMC (+) group had more errors than the SMC (-) group in the following four items regarding refrigerator management; the refrigerator has a lot of the same foods / expired food, the person does not know what's in the refrigerator, the person cannot find what he/she needs in the refrigerator. Moreover, SMC was associated with the item 'the person does not know what is in the refrigerator' (odds ratio 7.44, 95% CI 1.51-43.8, P = 0.02).

CONCLUSIONS

Our results showed that older adults with SMC had several problems regarding refrigerator management. Evaluating refrigerator management among older adults with SMC may help consider multifaceted support.

Subjective cognitive decline may mediate the occurrence of postoperative delirium by P-tau undergoing total hip replacement: The PNDABLE study

OBJECTIVE

We again investigated the relationship between subjective cognitive decline (SCD) and postoperative delirium (POD) with a larger sample queue. We also determined whether SCD could cause the occurrence of POD through cerebrospinal fluid (CSF) biomarkers.

METHODS

A prospective, observational cohort study was implemented in the Qingdao Municipal Hospital Affiliated with Qingdao University. This study recruited 1,471 qualified patients affiliated with the Perioperative Neurocognitive Disorder And Biomarker Lifestyle (PNDABLE) study scheduled for total hip replacement under combined spinal and epidural anesthesia from June 2020 to May 2022. The Mini-Mental State Examination (MMSE) and the Montreal Cognitive Assessment (MoCA) were used to assess the cognitive level of the patients the day before surgery. Pittsburgh sleeps quality index (PSQI) scale was used to assess sleep status. Patients were divided into the SCD group and the non-SCD (NSCD) group based on the Subjective Cognitive Decline Scale (SCDS). CSF was collected after a successful spinal-epidural combined puncture, and amyloid-β40 (Aβ40), amyloid-β42 (Aβ42), total tau (T-tau), and phosphorylated tau (P-Tau) in CSF were analyzed by enzyme-linked immunosorbent assays. After the surgery, the incidence of POD was determined by the Confusion Assessment Scale (CAM), and Memorial Delirium Assessment Scale (MDAS) score was used to determine the severity of POD. Logistic regression and sensitivity analyses were performed to determine the relationship between CSF biomarkers, SCD, and POD. The mediating effect was used to analyze the function of specific CSF biomarkers in the relationship between SCD and POD. The risk factors of SCD were also separately verified by logistic regression and sensitivity analysis models.

RESULTS

The total incidence rate of POD was 19.60% (n = 225/1148), which was 29.3% (n = 120/409) in the SCD group and 14.2% (n = 105/739) in the NSCD group. We comprehensively considered the effect of covariates such as age, hypertension, and diabetes. Multivariate logistic regression analysis showed that SCD (OR = 1.467, 95%CI: 1.015-2.120, p = 0.042) and P-tau (OR = 1.046, 95%CI: 1.028-1.063, p < 0.001) were risk factors for POD. The sensitivity analysis results were consistent with the above results. Mediation analysis showed that the relationship between SCD and POD was partially mediated by P-tau, which accounted for 31.25% (P-tau, IE = 4.279 × 10-2, p < 0.001). For SCD, the results of logistic regression analysis models showed that age (OR = 1.035, 95% CI: 1.020-1.049, p < 0.001), higher preoperative PSQI score (OR = 1.047, 95%CI: 1.014-1.080, p = 0.005), and P-tau (OR = 1.015, 95%CI: 1.002-1.028, p = 0.021) were risk factors for SCD, and subsequent sensitivity analysis confirmed this result after adjustment for ASA grade, height, and weight.

CONCLUSION

Patients with SCD are more likely to develop POD undergoing total hip replacement, and SCD can mediate the occurrence of POD via P-tau.

CLINICAL TRIAL REGISTRATION

This study was registered at China Clinical Trial Registry (Chictr2000033439).

Altered metamemory precedes cognitive impairment in subjective cognitive decline with positive amyloid-beta

Subjective cognitive decline (SCD) as an indicator of preclinical Alzheimer's disease (AD) may precede mild cognitive impairment (MCI) over several decades. Self-reported cognitive decline as a typical clinical manifestation is critical in preclinical AD. Metacognition represents a person's ability to accurately assess cognition. Our study aimed to examine (1) the alternations of metamemory in a cohort across the Alzheimer's continuum, (2) the association between metamemory and cognition, and (3) the relationship of cortical thickness in four regions of interest (ROI) with metamemory scores. Six hundred ninety-seven participants were classified as 79 AD dementia, 161 aMCI, 261 SCD, and 196 cognitively unimpaired (CU) individuals, in which 418 participants aged above 65, 131 participants with Aβ+ after receiving positron emission tomography, and 602 participants received sMRI. The degree of confidence (DOC) was measured by calculating discrepancies between judgments and memory performance. We assessed the relationships between DOC tertiles and cognition and analyzed the screening power, then investigated the partial correlation between DOC and ROIs, controlled by age, sex, and cognition. In the Aβ+ subgroup, SCD showed significantly higher DOC scores than the CU group. There was an increasing trend of overconfidence with the decline of cognition across the AD spectrum (P for trend < 0.001). After adjusting for age, sex, and education, the lower degree of confidence-long-term delay recall (DOC-LD) tertiles were associated with lower odds ratio in SCD, aMCI, and AD in the Aβ+ subgroup (all P for trend < 0.05). The area under the curves of DOC scores for screening SCD from CU in the Aβ+ subgroup was better than that in all participants and the age ≥65 subgroup. Partial correlation showed that in the Aβ+ subgroup, DOC-SD (degree of confidence-short-term delay recall) was negatively correlated with the anterior cingulate cortex; DOC-LD was negatively correlated with the cortices of parahippocampal, anterior cingulate, posterior cingulate, and medial orbitofrontal. In individuals with Aβ+, SCD exhibited a detectable metamemory alternation before objective cognitive impairment could be tested, indicated by the overestimation in the memory performance. The pattern of an increasing trend of overconfidence across SCD, aMCI, and AD dementia supports the view of a continuum in Alzheimer's disease.

The role of dyadic cognitive report and subjective cognitive decline in early ADRD clinical research and trials: Current knowledge, gaps, and recommendations

Efficient identification of cognitive decline and Alzheimer's disease (AD) risk in early stages of the AD disease continuum is a critical unmet need. Subjective cognitive decline is increasingly recognized as an early symptomatic stage of AD. Dyadic cognitive report, including subjective cognitive complaints (SCC) from a participant and an informant/study partner who knows the participant well, represents an accurate, reliable, and efficient source of data for assessing risk. However, the separate and combined contributions of self- and study partner report, and the dynamic relationship between the two, remains unclear. The Subjective Cognitive Decline Professional Interest Area within the Alzheimer's Association International Society to Advance Alzheimer's Research and Treatment convened a working group focused on dyadic patterns of subjective report. Group members identified aspects of dyadic-report information important to the AD research field, gaps in knowledge, and recommendations. By reviewing existing data on this topic, we found evidence that dyadic measures are associated with objective measures of cognition and provide unique information in preclinical and prodromal AD about disease stage and progression and AD biomarker status. External factors including dyad (participant-study partner pair) relationship and sociocultural factors contribute to these associations. We recommend greater dyad report use in research settings to identify AD risk. Priority areas for future research include (1) elucidation of the contributions of demographic and sociocultural factors, dyad type, and dyad relationship to dyad report; (2) exploration of agreement and discordance between self- and study partner report across the AD syndromic and disease continuum; (3) identification of domains (e.g., memory, executive function, neuropsychiatric) that predict AD risk outcomes and differentiate cognitive impairment due to AD from other impairment; (4) development of best practices for study partner engagement; (5) exploration of study partner report as AD clinical trial endpoints; (6) continued development, validation, and optimization, of study partner report instruments tailored to the goals of the research and population.

An application study-subjective cognitive decline Questionnaire9 in detecting mild cognitive impairment (MCI)

Objective: Subjective cognitive decline (SCD) complaints as the early manifestation of mild cognitive impairment (MCI) may be harbingers of objective cognitive decline. SCD-questinnaire9 (SCD-Q9) is developed to investigate the early sign for MCI. However, few studies have reported its power for discriminating MCI from healthy controls (HCs). Therefore, this study aims to investigate the discrimination power of SCD-Q9 as a brief screening tool for early detection of SCD in MCI.Methods: 84 HCs and 205 people with MCI were recruited. Their demographic information and scores of SCD-Q9 were compared. A binary logistic regression model was used to analyze the potential affecting factors of MCI, and the Receiver Operating Characteristic analysis was applied to test the discrimination powers of those factors, including SCD-Q9.Results: (1) Single and total scores of SCD-Q9 were all lower in the MCI group than those in the HC group. (2) Ageing, lower education and higher total scores of SCD-Q9 were associated with MCI. (3) Area Under the Curves (AUC) of SCD-Q9 for discriminating MCI from HC group was 0.815 and when integrating age and education, the AUC improved slightly and reached 0.839. Additionally, the sensitivity and specificity were 68.8% and 85.7%, respectively when a cut-off value of 3 was applied. Conclusions: SCD-Q9 may be able to detect the subjective cognitive decline in MCI early, but it may be used together with other screening questionnaires to improve its sensitivity and further verification of its power is needed.

Characteristics of subjective cognitive decline associated with amyloid positivity

INTRODUCTION

The evidence for characteristics of persons with subjective cognitive decline (SCD) associated with amyloid positivity is limited.

METHODS

In 1640 persons with SCD from 20 Amyloid Biomarker Study cohort, we investigated the associations of SCD-specific characteristics (informant confirmation, domain-specific complaints, concerns, feelings of worse performance) demographics, setting, apolipoprotein E gene (APOE) ε4 carriership, and neuropsychiatric symptoms with amyloid positivity.

RESULTS

Between cohorts, amyloid positivity in 70-year-olds varied from 10% to 76%. Only older age, clinical setting, and APOE ε4 carriership showed univariate associations with increased amyloid positivity. After adjusting for these, lower education was also associated with increased amyloid positivity. Only within a research setting, informant-confirmed complaints, memory complaints, attention/concentration complaints, and no depressive symptoms were associated with increased amyloid positivity. Feelings of worse performance were associated with less amyloid positivity at younger ages and more at older ages.

DISCUSSION

Next to age, setting, and APOE ε4 carriership, SCD-specific characteristics may facilitate the identification of amyloid-positive individuals.

Cognitive training modified age-related brain changes in older adults with subjective memory decline

OBJECTIVES

Neuroimaging findings suggest that older adults with subjective memory decline (SMD) demonstrate some neurodegenerative brain changes and have high risk of developing dementia, but relatively little is known about the effectiveness of interventions for SMD. This study aimed to examine the effects of cognitive training on resting-state brain activity in SMD.

METHOD

This study employed the amplitude of low frequency fluctuations (ALFF) and resting state functional connectivity (rs-FC) analyses. After baseline evaluations, participants were randomly allocated to the intervention and control group to receive a four-week cognitive training and lectures on health and aging, respectively. All participants were scanned before and after training with an interval of about three months.

RESULTS

(1) Participants in the intervention group showed significant improvements on the Associative Learning Test (ALT) and the Digit Span Forward task compared to the control group; (2) ALFF in the occipital lobe for the control group increased significantly, while that for the intervention group remained the same; ALFF changes were negatively correlated with ALT performance in the control group; (3) The mean value of rs-FC for the intervention group decreased, while that for the control group showed a trend of increase; rs-FC changes were also negatively correlated with ALT performance in the control group.

CONCLUSIONS

Resting-state brain activities in occipital region increased with aging. The cognitive training could counteract this brain function changes associated with aging or even reverse the changes. These findings provide new insights into the understanding of brain plasticity in posterior areas in SMD.

TRIAL REGISTRATION

ChiCTR-IOR-15006165 in the Chinese Clinical Trial Registry.

Tau levels are higher in objective subtle cognitive decline but not subjective memory complaint

BACKGROUND

The 2018 NIA-AA Alzheimer's Disease (AD) Research Framework states that subtle cognitive decline in cognitively unimpaired individuals can be measured by subjective reports or evidence of objective decline on neuropsychological measures. Both subjective memory complaint (SMC) and objective subtle cognitive decline (Obj-SCD) have been shown to be associated with future cognitive decline and AD biomarkers. We examined whether there are differences in tau PET levels between (a) SMC- vs. SMC+ participants, (b) Obj-SCD- vs. Obj-SCD+ participants, and (c) participants with overlapping vs. discrepant SMC and Obj-SCD classifications.

METHODS

Cognitively unimpaired participants from the Alzheimer's Disease Neuroimaging Initiative (ADNI; n = 236) were classified at baseline as positive or negative for SMC (SMC- n = 77; SMC+ n = 159) based on the first 12 items of the Cognitive Change Index and/or classified as positive or negative for Obj-SCD (Obj-SCD- n = 173; Obj-SCD+ n = 63) based on previously defined neuropsychological criteria. Analyses of covariance, adjusting for age, sex, APOE ε4 carrier status, and pulse pressure, examined the group differences in tau PET (AV-1451) using a composite standardized uptake variable ratio (SUVR) for regions consistent with Braak stage III/IV. The chi-squared tests examined the tau positivity rates across the groups.

RESULTS

Obj-SCD+ participants had higher tau continuous SUVR levels (p = .035, ηp2 = .019) and higher rates of tau positivity (15.8% Obj-SCD- vs. 30.2% Obj-SCD+) than Obj-SCD- participants. Neither tau levels (p = .381, ηp2 = .003) nor rates of tau positivity (18.2% SMC- and 20.1% SMC+) differed between the SMC groups. There was very little agreement between SMC and Obj-SCD classifications (42%; κ = 0.008, p = .862). Participants who were Obj-SCD+ without SMC had the highest tau PET levels and differed from participants who were SMC+ without Obj-SCD (p = .022). Tau levels in participants with both SMC and Obj-SCD did not differ from those with only Obj-SCD (p = .216). Tau positivity rates across the SMC-/Obj-SCD-, SMC+/Obj-SCD-, SMC-/Obj-SCD+, and SMC+/Obj-SCD+ groups were 10.5%, 18.1%, 40.0%, and 25.6%, respectively.

CONCLUSION

Participants with Obj-SCD had a greater tau PET burden than those without Obj-SCD, but SMC was not associated with higher tau levels. The combination of SMC and Obj-SCD did not have higher tau levels than Obj-SCD alone. Findings add to the evidence that the Obj-SCD classification is associated with AD biomarkers and faster cognitive decline in ADNI participants, but further work is needed to validate this approach in more representative/diverse cohorts.

The reliability and validity test of subjective cognitive decline questionnaire 21 with population in a Chinese community

BACKGROUND

Subjective cognitive decline-questionnaire 9 (SCD-Q9) was developed to detect SCD complaints at risk of mild cognitive impairment (MCI). However, our previous findings indicated that its coverage might be insufficient. To test this hypothesis, we recently translated SCD-Q21.

OBJECTIVE

To examine the reliability and validity of this translated SCD-Q21 and to explore its effectiveness for discriminating MCI from controls.

METHODS

Item analysis was performed to understand its item discrimination and homogeneity. The Cronbach's α and Spearman-Brown's split-half coefficients were calculated to test its reliability. The Kaiser-Meyer-Olkin (KMO) value, Bartlett's sphericity test, and exploratory factor analysis (EFA) were used to examine its construct validity. The content validity was evaluated using five-grade Likert scale. Finally, the SCD-Q21 scores in MCI and controls were compared.

RESULTS

The difference of each item between the extreme groups was significant. The Cronbach's α coefficient was .913 and Spearman-Brown's split-half coefficient was .894. When performing holding one-out approach, the Cronbach's α coefficient ranged from .906 to .914. The KMO value was .929 and the difference of Bartlett's Sphericity test was significant. All experts scored 5 points when assessing its content. Finally, a significant difference of score was found between MCI and NC groups.

CONCLUSIONS

The reliability and validity of the SCD-Q21 are good, which may pave a way for its application in a wider Chinese-speaking population.

Brain Amyloid Index as a Probable Marker Bridging Between Subjective Memory Complaint and Objective Cognitive Performance

Background

The association between types of subjective memory complaint (SMC), poor objective cognitive performance, and brain Aβ deposition have been poorly understood. We investigated the association between types of SMC and objective global cognitive performance, then assessed whether this association is mediated by the brain amyloid prediction index (API).

Methods

In total, 173 non-demented older adults [63 cognitively normal (CN) and 110 mild cognitive impairment (MCI)] underwent comprehensive clinical assessments. Objective global cognitive performance and brain amyloid index were measured using the total score (TS) of the Consortium to Establish a Registry for Alzheimer’s Disease neuropsychological battery and API, respectively. In total, four items of SMC from the subjective memory complaints questionnaire (SMCQ) (SMCQ1: a feeling of memory problem; SMCQ2: the feeling of worse memory than 10 years ago; SMCQ3: the feeling of worse memory than others of similar age; or SMCQ4: the feeling of difficulty in everyday life) in global memory function were assessed.

Results

In non-demented and participants with MCI, SMCQ3-positive and SMCQ4-positive groups were associated with decreased TS. In participants with MCI, the SMCQ3-positive group was associated with increased API, and API was associated with decreased TS, but the SMCQ4-positive group did not. In addition, the association between the SMCQ3-positive group and poor TS disappeared when API was controlled as a covariate, indicating that API has a mediation effect.

Conclusion

The present findings suggest that SMC, a feeling of worse memory performance than others in a similar age group, in the older adults without dementia is associated with poor objective cognitive performance via increased brain amyloid index.

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

Background

Depressive and anxiety symptoms are frequent in Alzheimer’s disease and associated with increased risk of developing Alzheimer’s disease in older adults. We sought to examine their relationships to Alzheimer’s disease biomarkers across the preclinical and clinical stages of the disease.

Method

Fifty-six healthy controls, 35 patients with subjective cognitive decline and 56 amyloid-positive cognitively impaired patients on the Alzheimer’s continuum completed depression and anxiety questionnaires, neuropsychological tests and neuroimaging assessments. We performed multiple regressions in each group separately to assess within group associations of depressive and anxiety symptoms with either cognition (global cognition and episodic memory) or neuroimaging data (gray matter volume, glucose metabolism and amyloid load).

Results

Depressive symptoms, but not anxiety, were higher in patients with subjective cognitive decline and cognitively impaired patients on the Alzheimer’s continuum compared to healthy controls. Greater depressive symptoms were associated with higher amyloid load in subjective cognitive decline patients, while they were related to higher cognition and glucose metabolism, and to better awareness of cognitive difficulties, in cognitively impaired patients on the Alzheimer’s continuum. In contrast, anxiety symptoms were not associated with brain integrity in any group.

Conclusion

These data show that more depressive symptoms are associated with greater Alzheimer’s disease biomarkers in subjective cognitive decline patients, while they reflect better cognitive deficit awareness in cognitively impaired patients on the Alzheimer’s continuum. Our findings highlight the relevance of assessing and treating depressive symptoms in the preclinical stages of Alzheimer’s disease.

APOE ε4 Allele Distribution and Association With Scores of Subjective Cognitive Decline Questionnaire 9 in a Large Chinese Memory Clinic Cohort

Background

Previous reports on APOE ε4 allele distribution in different populations have been inconclusive. The Subjective Cognitive Decline-Questionnaire 9 (SCD-Q9) was developed to identify those at risk of objective cognitive impairment [OCI; including mild cognitive impairment (MCI) and dementia groups), but its association with APOE ε4 and discriminatory powers for SCD_{with subtle cognitive decline} (SCDs) and OCI in memory clinics are unclear.

Objectives

To investigate demographic distribution of APOE ε4, its association with SCD-Q9 scores, and its ability to discriminate SCDs and OCI groups from normal control (NC).

Methods

A total of 632 participants were recruited (NC = 243, SCDs = 298, OCI = 91). APOE ε4 allele distribution and association with SCD-Q9 scores were calculated and the effects on cognitive impairment were analyzed. Receiver operating characteristic (ROC) analysis was applied to identify discriminatory powers for NC, SCDs, and OCI.

Results

Total APOE ε4 frequency was 13.1%. This did not vary by demography but was higher in patients with OCI. The SCD-Q9 scores were higher in APOE ε4 carriers than non-carriers in the OCI group. The area under the curve (AUC) for discriminating from OCI using APOE ε4 were 0.587 and 0.575, using SCD-Q9 scores were 0.738 and 0.571 for NC and SCDs groups, respectively. When we combined APOE ε4 and SCD-Q9 scores into the model, the AUC increased to 0.747 for discriminating OCI from NC. However, when OCI group was split into MCI and dementia groups, only total SCD-Q9 score was the independent affecting factor of MCI.

Conclusion

This study demonstrated that the distribution of APOE ε4 alleles did not vary with different demographic characteristics in a large-scale cohort from a memory clinic. APOE ε4 alleles may be associated with scores of SCD-Q9 reflecting the degree of cognitive complaints but their additional contribution to SCD-Q9 scores is marginal in discriminating between NC, SCDs, and OCI.