The characterisation of subjective cognitive decline

The Role of Sensory Impairment in Cognitive Health Appraisal: A Study of Older Korean Americans Living in Subsidized Senior Housing

ObjectivesWe examined how the association between cognitive performance and cognitive health appraisal would be moderated by vision and/or hearing impairment.MethodsData were collected from 315 older Korean-American residents in subsidized senior housing in Los Angeles (M age = 79.4 years). Linear regression models examined the direct and interactive effects of cognitive performance, vision impairment, and hearing impairment on cognitive health appraisal.ResultsNegative appraisal of cognitive health was associated with lower cognitive performance and poorer ratings for vision and hearing. Moreover, we found a significant interaction between cognitive performance and hearing impairment (β = .13, p < .05), as well as a three-way interaction among cognitive performance, vision impairment, and hearing impairment (β = .12, p < .05).DiscussionThe association between objective and subjective measures of cognition was weakened when hearing was impaired. Such a pattern was further evident when both vision and hearing were impaired.

Objective Criteria for Subtle Cognitive Decline in Aging and Preclinical Alzheimer Disease: A Systematic Review

BACKGROUND AND OBJECTIVES

Although the Alzheimer's Association (AA) biomarker-only Alzheimer disease (AD) criteria and the International Working Group clinical-pathologic AD criteria differ, both approaches appreciate the need for early detection efforts. Within the AA approach, clinical stage 2 recognizes that someone can be cognitively unimpaired but still experience "subtle cognitive decline" (SCD) measured by subjective report or objective decline using neuropsychological measures. While significant attention has been given to subjective cognitive decline methods, there are no systematic examinations of the operational definition of SCD using objective neuropsychological measures. Therefore, the primary aim of this review was to identify and describe the approaches used to classify objective SCD.

METHODS

A systematic literature search was performed using PubMed/MEDLINE, Web of Science, and PsycInfo databases for articles with dates ranging from the start of the database through November 1, 2023. Included studies were peer-reviewed, described a discrete objective SCD category, included participants aged 50+ without mild cognitive impairment (MCI) or dementia, and focused on aging or AD. A modified Newcastle-Ottawa Scale was used to assess the quality of included studies. Data were extracted by the 2 authors who then categorized and described the classification approaches.

RESULTS

Of the 1,361 publications initially identified, 70 case-control studies met criteria for inclusion. SCD definitions generally fell into 6 categories based on using similar methodology: (1) SCD based on a specified cutoff on a single cognitive test (n = 6); (2) SCD based on a cutoff (e.g., 10th percentile) on a cognitive composite score (n = 9); (3) objectively defined SCD (Obj-SCD) using cutoffs (e.g., -1 SD) on multiple individual neuropsychological measures (n = 24); (4) "Pre-MCI" criteria defined using a Clinical Dementia Rating of 0.5 but normal performance on neuropsychological testing (n = 12); (5) cutoff based on longitudinal rate of cognitive decline (e.g., over 1 year) (n = 13); and (6) data-driven/clustering approach to classification (n = 8). Two studies used multiple classification approaches.

DISCUSSION

Six promising classification approaches were identified in the existing literature, with the Obj-SCD and Pre-MCI approaches being the most commonly applied. Additional work is needed to compare SCD approaches head-to-head to identify the most prognostically useful, particularly within racially/ethnically diverse older adults.

Subjective cognitive decline in conjunction with cerebrospinal fluid anti-ATP1A3 autoantibodies and a low amyloid β 1-42/1-40 ratio: Report and literature review

BACKGROUND

Animal studies reveal the role of the sodium/potassium transporting ATPase α-3 subunit (ATP1A3) in maintaining the resting membrane potential and thus in synaptic information processing and potentially cognitive disorders. However, autoantibodies against AT1A3 have not previously been reported in patients with subjective cognitive decline.

CASE PRESENTATION

We report the case of a 57-year-old female who underwent neuropsychological testing, magnetic resonance imaging (MRI) and 18 F fluorodesoxyglucose positron emission tomography (FDG-PET) imaging, and cerebrospinal fluid (CSF) analysis. Neural autoantibodies were assessed in serum and CSF. We found a normal cognitive profile together with a self-reported cognitive decline, and such consistent with subjective cognitive decline (SCD). Analysis of the cerebrospinal fluid revealed anti-ATP1A3 autoantibodies. ATP1A3 autoantibodies were also detected in serum. Analysis of amyloid pathology markers in the CSF showed a slightly reduced amyloid β1-42/ amyloid β1-40 ratio. In view of the possible paraneoplastic autoantibodies, whole-body FDG-PET was performed, which did not reveal a malignancy-specific lesion. FDG-PET of the brain also showed no hypometabolism. We diagnosed SCD based on CSF-affirmed possible Alzheimer´s pathologic change with ATP1A3 autoantibodies in CSF and serum.

CONCLUSIONS

To our knowledge, this is the first report of CSF and serum ATP1A3 autoantibodies associated with SCD although an incidental finding cannot be fully excluded. In addition, amyloid pathology was detected via CSF biomarkers, suggesting that ATP1A3 autoantibodies are a potentially promising biomarker in SCD with an Alzheimer´s pathologic change if confirmed in large-scale studies.

Forecasting Subjective Cognitive Decline: AI Approach Using Dynamic Bayesian Networks

BACKGROUND

Several potentially modifiable risk factors are associated with subjective cognitive decline (SCD). However, developmental patterns of these risk factors have not been used before to forecast later SCD. Practical tools for the prevention of cognitive decline are needed.

OBJECTIVE

We examined multifactorial trajectories of risk factors and their associations with SCD using an artificial intelligence (AI) approach to build a score calculator that forecasts later SCD. In addition, we aimed to develop a new risk score tool to facilitate personalized risk assessment and intervention planning and to validate SCD against register-based dementia diagnoses and dementia-related medications.

METHODS

Five repeated surveys (2000-2022) of the Helsinki Health Study (N=8960; n=7168, 80% women, aged 40-60 years in phase 1) were used to build dynamic Bayesian networks for estimating the odds of SCD. The model structure was developed using expert knowledge and automated techniques, implementing a score-based approach for training dynamic Bayesian networks with the quotient normalized maximum likelihood criterion. The developed model was used to predict SCD (memory, learning, and concentration) based on the history of consumption of fruit and vegetables, smoking, alcohol consumption, leisure time physical activity, BMI, and insomnia symptoms, adjusting for sociodemographic covariates. Model performance was assessed using 5-fold cross-validation to calculate the area under the receiver operating characteristic curve. Bayesian credible intervals were used to quantify uncertainty in model estimates.

RESULTS

Of the participants, 1842 of 5865 (31%) reported a decline in memory, 2818 of 5879 (47.4%) in learning abilities, and 1828 of 5888 (30.7%) in concentration in 2022. Physical activity was the strongest predictor of SCD in a 5-year interval, with an odds ratio of 0.76 (95% Bayesian credible interval 0.59-0.99) for physically active compared to inactive participants. Alcohol consumption showed a U-shaped relationship with SCD. Other risk factors had minor effects. Moreover, our validation confirmed that SCD has prognostic value for diagnosed dementia, with individuals reporting memory decline being over 3 times more likely to have dementia in 2017 (age 57-77 years), and this risk increased to more than 5 times by 2022 (age 62-82 years). The receiver operating characteristic curve analysis further supported the predictive validity of our outcome, with an area under the curve of 0.78 in 2017 and 0.75 in 2022.

CONCLUSIONS

A new risk score tool was developed that enables individuals to inspect their risk profiles and explore potential targets for interventions and their estimated contributions to later SCD. Using AI-driven predictive modeling, the tool can aid health care professionals in providing personalized prevention strategies. A dynamic decision heatmap was presented as a communication tool to be used at health care consultations. Our findings suggest that early identification of individuals with SCD could improve targeted intervention strategies for reducing dementia risk. Future research should explore the integration of AI-based risk prediction models into clinical workflows and assess their effectiveness in guiding lifestyle interventions to mitigate SCD and dementia.

Cerebrospinal fluid proteome profiling across the Alzheimer's disease continuum: a step towards solving the equation for 'X'

BACKGROUND

While the temporal profile of amyloid (Aβ) and tau cerebrospinal fluid (CSF) biomarkers along the Alzheimer's disease (AD) continuum is well-studied, chronological changes of CSF proteins reflecting other disease-relevant processes, denoted 'X' in the ATX(N) framework, remain poorly understood.

METHODS

Using an untargeted mass spectrometric approach termed tandem mass tag (TMT), we quantified over 1500 CSF proteins across the AD continuum in three independent cohorts, finely staged by Aβ/tau positron emission tomography (PET), fluid biomarkers, or brain biopsy. Weighted protein co-expression network analysis identified clusters of proteins robustly correlating in all three cohorts which sequentially changed with AD progression. Obtained protein clusters were correlated with fluid biomarker measurements (phosphorylated tau (p-tau) species including p-tau181, p-tau217, and p-tau205, as well as Aβ), Aβ/tau PET imaging, and clinical parameters to discern disease-relevant clusters which were modelled across the AD continuum.

RESULTS

Neurodegeneration-related proteins (e.g., 14-3-3 proteins, PPIA), derived from different brain cell types, strongly correlated with fluid as well as imaging biomarkers and increased early in the AD continuum. Among them, the proteins SMOC1 and CNN3 were highly associated with Aβ pathology, while the 14-3-3 proteins YWHAZ and YWHAE as well as PPIA demonstrated a strong association with both Aβ and tau pathology as indexed by PET. Endo-lysosomal proteins (e.g., HEXB, TPP1, SIAE) increased early in abundance alongside neurodegeneration-related proteins, and were followed by increases in metabolic proteins such as ALDOA, MDH1, and GOT1 at the mild cognitive impairment (MCI) stage. Finally, later AD stages were characterized by decreases in synaptic/membrane proteins (e.g., NPTX2).

CONCLUSIONS

Our study identified proxies of Aβ and tau pathology, indexed by PET, (SMOC1, YWHAE, CNN3) and highlighted the dynamic fluctuations of the CSF proteome over the disease course, identifying candidate biomarkers for disease staging beyond Aβ and tau.

Aging and the neuropsychiatry of multiple sclerosis: a cross-sectional study

Aging in multiple sclerosis (MS) affects clinical and radiological disease activity. Yet, evidence is equivocal about the effects of aging on the neuropsychiatric sequelae of MS, including anxiety, depression, fatigue, and cognitive dysfunction. This study aimed to clarify how the neuropsychiatric symptoms of MS vary across ages. A consecutive cohort of 1194 people with MS (pwMS) underwent neuropsychological testing using the Minimal Assessment of Cognitive Function in MS, the Hospital Anxiety and Depression Scale sub-scales for anxiety (HADS-A) and depression (HADS-D), Modified Fatigue Impact Scale (MFIS), and the Perceived Deficits Questionnaire (PDQ) for cognitive complaints. Participants were stratified into age sub-groups: 18-29, 30-39, 40-49, 50-59 years. t-tests were undertaken to compare symptoms between the 18-29 and 50-59 sub-groups. Linear regression analyses, controlling for disability (Expanded Disability Status Scale; EDSS), sex, educational years, and high-efficacy disease-modifying therapy use, were used to evaluate whether age significantly predicted neuropsychiatric sequelae. Mean age was 42.15 years, 74.12% were female, and median EDSS was 2.00. Older pwMS had reduced HADS-A, PDQ, California Verbal Learning Test (CVLT), Brief Visuospatial Memory Test (BVMT), Symbol Digit Modalities Test (SDMT), and Delis-Kaplan Executive Function System (D-KEFS) scores, all p < 0.01. There were no age differences on the HADS-D, MFIS, Controlled Oral Word Association Test, Judgment of Line Orientation, or Paced Auditory Serial Addition Test. Controlling for covariates, older age independently predicted reduced HADS-A, CVLT, BVMT, SDMT, and D-KEFS scores, all p < 0.01. In summary, as pwMS age, anxiety declines and performance on learning, memory, processing speed, and executive function tests worsens.

Lower Odor Identification in Subjective Cognitive Decline: A Meta-analysis

INTRODUCTION

Odor identification correlates with Alzheimer's disease (AD) biomarkers, and its decline may emerge before measurable cognitive deficits as early as the subjective cognitive decline (SCD) stage. We aimed to compare odor identification between SCD and cognitively normal (CN) stages and investigate whether cognitive differences moderate olfactory deficits.

METHODS

A systematic search of four databases identified studies assessing olfactory identification and cognitive screening in individuals aged 50+. A random-effects meta-analysis was performed on 11 studies (660 SCD, 574 CN).

RESULTS

Individuals with SCD exhibited lower olfactory identification scores compared to CN participants (SMD = -0.67, 95%CI [-1.31, -0.03], p = .04). Meta-regression revealed a negative association (β = -1.79, p = .02) between cognitive and olfactory differences, indicating that greater cognitive decline was not consistently associated with greater olfactory deficits, lower odor identification scores in SCD occurred despite minimal cognitive differences across groups.

DISCUSSION

Odor identification is lower in pre-MCI individuals reporting SCD. Olfactory decline may emerge independently prior to measurable cognitive decline, supporting the role of odor identification as a screen for AD.

Active information sampling in health and disease

Active information gathering is a fundamental cognitive process that enables organisms to navigate uncertainty and make adaptive decisions. Here we synthesise current knowledge on the behavioural, neural, and computational mechanisms underlying information sampling in healthy people and across several brain disorders. The role of cortical and subcortical regions spanning limbic, insular, fronto-parietal, and striatal systems is considered, along with the contributions of key neurotransmitters involving norepinephrine, dopamine, and serotonin. We also examine how various clinical conditions, including schizophrenia, obsessive-compulsive disorder, and Parkinson's disease have an impact on information gathering behaviours. To account for the findings, we outline a neuroeconomic perspective on how the brain may evaluate the costs and benefits of acquiring information to resolve uncertainty. This work high- lights how active information gathering is a crucial brain process for adaptive behaviour in healthy individuals and how its breakdown is relevant to several psychiatric and neurological conditions. The findings have important implica- tions for developing novel computational assays as well as targeted interven- tions in brain disorders.

Normative data for the 12-item Buschke memory task in the Quebec-French population aged 50 and over

OBJECTIVE

The 12-item Buschke memory test is used to assess verbal episodic memory in adults and older adults. However, there is no normative data for this test adjusted to the older Quebec-French population. The aim of the study was to produce normative data for the 12-item Buschke for the Quebec-French population aged 50 and older.

METHOD

The normative sample consisted of 172 healthy French-speaking participants aged 50-89 years, from the Province of Quebec (Canada). The influence of age, years of formal education, and sex on five 12-item Buschke scores were analyzed. Based on the distribution of scores, normative data were developed as Z-scores equation, regression equation, and percentiles.

RESULTS

Age, years of formal education, and sex were all associated with performance. Equations to calculate Z-scores were provided for the free recall trial 1 and the free recall trials 1-3. Stratified percentiles were provided for the delayed free recall and total recall 1-3.

CONCLUSIONS

The normative data for the 12-item Buschke improve the accuracy of clinicians to detect verbal episodic memory impairments in Quebec's aging population.

Longitudinal, Bidirectional Association between Gait Speed and Cognitive Function in Community-Dwelling Older Adults without Dementia

OBJECTIVES

The causal relationship between slow gait speed and poor cognition is uncertain due to potential reverse causality. This study aimed to examine the reciprocal relationship between gait speed and global as well as domain-specific cognitive functions in older adults.

DESIGN

Prospective cohort study (2013-2022) including 4 repeated measures.

SETTINGS AND PARTICIPANTS

Community-dwelling and adults without dementia aged ≥65 recruited at baseline.

METHODS

Biennial evaluations included assessments of 4-m usual walking speed, global cognition using the Taiwanese version of the Montreal Cognitive Assessment (MoCA), and cognitive domains (memory, executive function, verbal fluency, and attention) using a battery of neuropsychological tests. Cross-lagged models and linear mixed models were used to examine the bidirectional association between gait speed and cognitive functions with adjustment for potential confounders.

RESULTS

At baseline, 511 participants were enrolled, and 459 individuals with a mean age of 74.5 years were ultimately analyzed. A 1-SD decrease in gait speed was associated with a 0.07-0.09 SD decrease in subsequent global cognition [βˆWave 1→2: 0.07, standard error (SE): 0.03; βˆWave 2→3: 0.09, SE: 0.04; βˆWave 3→4: 0.09, SE: 0.04; all P < .05]. Similarly, a 1-SD decrease in global cognition was associated with a 0.18 to 0.19 SD decrease in subsequent gait speed (βˆWave 1→2: 0.18, SE: 0.05; βˆWave 2→3: 0.18, SE: 0.06; βˆWave 3→4: 0.19, SE: 0.07; all P < .001). In addition, slower gait speed was associated with poor memory, verbal fluency, and executive function, and vice versa. The results of linear mixed models were consistent with the findings obtained from cross-lagged models.

CONCLUSIONS AND IMPLICATIONS

This study found a reciprocal association between gait speed and global or domain-specific cognition. Regularly screening gait speed and cognitive function enables the early detection of declines in physical function and cognition.

Feasibility and acceptability of remote APOE-genotyping among research volunteers of an online recruitment registry (The Dutch Brain Research Registry)

BACKGROUND

Participant recruitment for preclinical Alzheimer's disease (AD) prevention studies is challenging. Online registries facilitate large scale prescreening of individuals at risk for AD to accelerate recruitment. APOE-prescreening has the potential to better identify at-risk individuals. This study investigated the feasibility and acceptability of at-home APOE-genotyping in cognitively-normal registrants of an online registry.

METHODS

We invited 9,287 cognitively-normal registrants of Dutch Brain Research Registry (DBRR) aged 50 to 75 for at-home APOE-genotype testing, without receiving the results. Feasibility was measured by participation ratio (participation/interested), swab-return ratio (returned-swabs/participation), and genotyping-success ratio (analyzed swabs/returned swabs). Acceptability was measured with online questions about information provision and project scope. We explored prescreening questions potentially reducing screen-failures.

RESULTS

Feasibility was high with an 0.89 participation ratio (2,886/3,251), 0.90 swab-return ratio (2,886/2,597), 0.99 genotyping-success ratio (2,558/2,597). Acceptability was high, as participants were content with the information provision (87 %-97 %, n= 1,709-1,894), which was also well understood (91 %-93 %, n = 1,772-1,802). Among successful-analyzed swabs (n = 2,558), 27 % participants were APOE-ε4 heterozygote (n = 703), and 2 % homozygote (n = 60). Prescreening on a positive family history leads to a third reduction in the number of invitations needed to identify one APOE-ε4 carrier.

CONCLUSION

Our results suggest that APOE-ɛ4 genotyping in participants of an online research registry is feasible, well received and could be used to prescreen individuals at risk for AD for prevention studies. Adding a positive family history before invitation for APOE-genotyping, would further improve the prescreening process and reduce screen failures when identifying carriers.

Age moderates associations between dementia worry and subjective cognition

The present study assessed whether dementia worry is associated with adults' subjective cognitive difficulties, and whether any associations are moderated by age. Participants were 477 adults aged 18-90 years. They completed standard, subjective measures of dementia worry and everyday cognitive difficulties (i.e. attention, language, verbal and visual-spatial memory, and visual-perceptual ability). Moderated regression analyses included dementia worry as a predictor of specific cognitive difficulties, and age as a moderator. Covariates included gender, trait cognitive and somatic anxiety, general aging-related anxiety, depression, stress, mental health treatment status, and health status. Greater overall dementia worry, and specifically more frequent dementia worry, were both associated with greater attentional difficulty in middle-aged and older adults, but not in young adults. Cognitions about developing dementia in reaction to memory lapses were also associated with greater cognitive difficulties across the adult lifespan for multiple cognitive domains. Results highlight a robust relationship between dementia worry and subjective attentional difficulties, especially in middle-aged and older adults. Worry frequency is also more influential with adult aging. A cognitive or meta-cognitive mechanism may underlie subjective cognitive concerns across the adult lifespan.

Development of the subjective cognitive function decline scale for middle-aged Koreans

OBJECTIVES

This study developed the Subjective Cognitive Function Decline Scale for Middle-aged South Koreans (SCFD-K), addressing the need for early detection of potential mild cognitive impairment. This study fills a gap in the existing research, which mainly targeted older demographics or generalized cultural differences.

METHOD

We conducted focus group interviews (FGIs) among 36 participants and with nine experts to answer basic questions related to cognitive decline, after which we developed a draft scale using the Delphi with another 15 experts. To examine the reliability and validity of the scale, an online survey of 2,000 people was conducted.

RESULTS

An exploratory factor analysis identified four distinct factors, which are language, visuospatial function, personality/emotion, and memory, with a total of 20 items (Cumulative variance ratio = 57.76), and a confirmatory factor analysis validated the four-factor structure with a good model fit (CFI = 0.932, TLI = 0.921, RMSEA = 0.057, and SRMR = 0.042) and acceptable internal consistency (Cronbach's α = 0.735-0.907).

CONCLUSION

This analysis established the SCFD-K as a reliable and valid tool for assessing cognitive decline among middle-aged South Koreans. The findings have key cultural implications and inform proactive interventions and shaping future healthcare strategies in South Korea.

Distinct trajectories of subjective cognitive decline before diagnosis of neurocognitive disorders: Longitudinal modelling over 18 years

BACKGROUND

Subjective cognitive decline (SCD) is an established predictor of neurocognitive disorders (NCD) (i.e. mild cognitive impairment and dementia). Yet, its construct remains contentious. Many individuals with SCD do not progress to NCD, leading to an alternative term in the literature - 'functional cognitive disorders' - to describe the SCD experience in these individuals.

OBJECTIVES

To examine the distinct differences in trajectories of SCD between those who did and did not eventually develop NCD.

DESIGN

Case-control study.

SETTING

Alzheimer's Disease Centers across USA.

PARTICIPANTS

A total of 5,167 participants aged ≥50 years were followed up near-annually to evaluate for SCD and NCD (median follow-up=8.1 years; range=1.0-18.0). Cases were defined as those who developed incident NCD during follow-up; controls completed ≥10 years of follow-up and had normal cognition throughout follow-up period.

MEASUREMENTS

SCD was evaluated with a yes/no question based on "perceived decline in memory relative to previously attained abilities". The trajectories of SCD were modelled with mixed-effect logistic regression, using a backward timescale.

RESULTS

Those who developed NCD (cases) had new onset of SCD within past 20 years, which became particularly noticeable 13-14 years before diagnosis, and became even more evident in the last 4 years. Those who did not develop NCD (controls) reported SCD since younger age, with the probability of SCD remaining constant over time. The distinctive trajectories were consistent across Alzheimer's and non-Alzheimer's disease, and among those with higher baseline rates of SCD due to psychiatric conditions.

CONCLUSIONS

SCD exhibits distinctive trajectories among those who do and do not progress to NCD. These distinctive trajectories can inform NCD risk for early interventions, and guide public health messaging to distinguish high-risk SCD from normal ageing. Future SCD scales may possibly need to evaluate symptom changes over a longer, 20-year horizon to better capture the new onset of SCD within this longer timeframe.

Normative data for the verb fluency test in the adult French-Quebec population and validation study in mild cognitive impairment

Verbal fluency tests are used to assess executive functions and language. The verb fluency test has proven successful in distinguishing healthy individuals (HCs) from participants with pathological conditions. However, few normative and psychometric studies have been published for the verb fluency test. The aim of Study 1 was to provide normative data in the adult population of French Québec for the verb fluency test. The aim of Study 2 was to determine its discriminant validity and test-retest reliability. The normative sample consisted of 424 HCs aged 50-92 years. Multiple linear regressions were used to generate equations for calculating Z-scores. To assess discriminant validity, the performance of 46 HCs was compared with that of 46 participants with mild cognitive impairment (MCI). To determine test-retest reliability, the test was administered twice, 3 months apart, to a group of 25 HCs. Age, sex, and education level were significantly related to performance on the test. The test distinguished the performance of HCs from that of participants with MCI. Test-retest analysis showed that scores had good stability over time. Norms and psychometric data for the verb fluency test will help clinicians and researchers better identify executive and language impairments associated with pathological conditions.

Lower semantic verbal fluency at baseline indicates future decline in subjective cognitive decline

Subjective cognitive decline (SCD) refers to a condition in which older adults are concerned that they are experiencing a decline in cognitive function. The risk of developing Alzheimer's disease (AD) is significantly higher in older adults with SCD, as a proportion of them will go on to develop the disease over the years. Despite overall normal function on cognitive tests, evidence suggests that some SCD individuals may have circumscribed deficits in specific cognitive domains or tests. This study aimed to investigate semantic function in SCD, specifically by comparing the performance of SCD progressors (SCDp) - who fulfilled MCI criteria at follow-up, and SCD non-progressors (SCDnp) - who either remained stable or reverted to normal cognition. The main hypothesis was that the SCDp group would show significantly lower semantic performance than the SCDnp group at baseline. We also expected the SCDp group to decline faster on semantic tests at the two-year follow-up assessment than SCDnp. Data from the CIMA-Q cohort were analyzed. The SCDp and SCDnp groups were formed by precisely matching 25 participants from each group based on age and education levels. Both groups were compared in terms of neuropsychological performance at baseline and follow-up. Independent samples t-tests or ANCOVAs were used to measure baseline performance in the semantic domain and other cognitive domains. To study longitudinal changes in cognitive performance at follow-up, two-factor ANOVAs were performed. At baseline, SCDp participants performed significantly worse than SCDnp participants on the Category (semantic) fluency test, although this difference was not maintained at follow-up. No difference was found in other cognitive domains at baseline. Longitudinal analyses showed that a significant decline in MoCA score was observed in the SCDp group only. The results of this study suggest that reduced verbal semantic fluency in older people with SCD may indicate a higher risk of future cognitive decline.

Collaborative learning in older age and the role of familiarity: evidence from the map task

As we age, learning new knowledge and skills becomes more difficult due to age-related changes to cognition. Learning collaboratively could counteract these changes, and perhaps more so when working with someone familiar. This study examined whether collaborative learning is affected by age and partner familiarity. Forty-eight participants (younger n = 24, older n = 24) completed the Map Task with a familiar and unfamiliar same-age partner. Participants became more efficient at completing the Map Task over time, regardless of age and partner familiarity. There was no age difference in immediate or 1-hour recall, but younger adults recalled more after 7 days than older adults. Overall, results suggest that collaborative learning outcomes are unaffected by age or partner familiarity and that collaborative learning has short-term protective effects on memory, with age-related declines only emerging after 7 days.

[Effects of a personalised, adapted computerised cognitive stimulation programme versus stimulating leisure activities in younger and older adults with mild or subjective cognitive impairment. Protocol for a randomised controlled trial]

BACKGROUND

Mild cognitive impairment represents a transitional stage between healthy aging and dementia, with subjective cognitive impairment being a key predictor of progression to dementia. This randomized controlled trial aims to compare the effectiveness of a personalized computerized cognitive stimulation program with that of stimulating leisure activities in younger and older adults with mild or subjective cognitive impairment.

METHODS

Participants aged = 50 with mild cognitive impairment, subjective cognitive impairment, or scores between 24 and 31 on the Spanish Mini-Mental State Examination were recruited. Exclusion criteria comprised living in residential care, use of acetylcholinesterase inhibitors, sensory impairments, agitation, or having received cognitive stimulation in the past 12 months. Fifty-nine community-dwelling individuals in Zaragoza, Spain, were randomly assigned to two interventions group or a control group. The first intervention group will receive personalized computerized cognitive stimulation for 30 minutes per day, five days per week, while the second intervention group will participate in two to five stimulating leisure activities. The intervention will last eight weeks. The control group will receive the usual care for the same duration. The primary outcome is the assessment of global cognition; secondary outcomes include memory, verbal fluency, activities of daily living, and mood.

Longitudinal automated brain volumetry versus expert visual assessment of atrophy progression on MRI: an exploratory study

Automated tools have been proposed to quantify brain volume for suspected dementia diagnoses. However, their robustness in longitudinal, real-life cohorts remains unexplored. This exploratory study examined if expert visual assessment (EVA) of atrophy progression is reflected by automated volumetric analyses (AVA) on sequential MR-imaging. We analyzed a random subset of 20 patients with two consecutive 3D T1-weighted examinations (median follow-up 4.0 years, LQ-UQ: 2.1-5.2, range: 0.2-10). Thirteen (65%) with cognitive decline, the remaining with other neuropsychiatric diseases. EVA was performed by two blinded neuroradiologists using a 3 or 5-point Likert scale for atrophy progression (scores ± 0-2: no, probable and certain progression or decrease, respectively) in dementia-relevant brain regions (frontal-, parietal-, temporal lobes, hippocampi, ventricles). Differences of AVA-volumes were normalized to baseline (delta). Inter-rater agreement of EVA scores was excellent (κ = 0.92). AVA-delta and EVA showed significant global associations for the right hippocampus (pKW = 0.035), left temporal lobe (pKW = 0.0092), ventricle volume (pKW = 0.0091) and a weak association for the parietal lobe (pKW = 0.067). Post hoc testing revealed additional significant link for the left hippocampus (pWSRT = 0.039). In conclusion, the associations between volumetric deltas and EVA of atrophy progression showed promising results for certain brain regions. However, AVA-deltas exhibited unexpected variance, highlighting the need for caution and expert visual confirmation, particularly when scanners or acquisition protocols vary during follow-ups. Therefore, further validation, ideally in large prospective cohorts, is necessary before AVA can be recommended for routine clinical implementation in longitudinal follow-ups.

Normative Data for the Alternating and Orthographic Constraint Semantic Fluency Tests in the Adult French-Quebec Population and Validation Study in Mild Cognitive Impairment and Alzheimer's Disease

Verbal fluency tests, known to elicit executive functions (EFs), have proven useful in distinguishing healthy individuals from those with cognitive impairment. The present study addresses two new tests of verbal fluency that elicit EFs, namely, extradimensional alternating fluency (EAF) and extradimensional orthographic constraint semantic fluency (EOCSF). The aim of Study 1 was to provide normative data in the adult and elderly population of French Québec for the two fluency tests. The aim of Study 2 was to determine their psychometric value. The normative sample consisted of 338 healthy controls (HCs) aged 50-89 years. Multiple linear regressions were used to generate equations for calculating Z-scores. Convergent validity was established by administering the two verbal fluency tests and the Letter-Number Sequence (LNS) subtest of the WAIS-III. To assess predictive validity, the performance of 19 HCs was compared with that of 19 participants with mild cognitive impairment (MCI) and 19 participants with Alzheimer's disease (AD). To determine test-retest reliability, the test was administered twice, 3 months apart, to a subsample of 20 HCs. Age and educational level were significantly related to performance in the EAF and the EOCSF. The two tests correlated significantly and positively with the LNS. The EAF and the EOCSF distinguished the performance of HCs from that of participants with MCI or AD. A test-retest analysis showed that scores on the two tests were stable over time. The norms and psychometric data for the EAF and the EOCSF will help clinicians and researchers better identify executive impairments associated with pathological conditions.

Normative Data for the Famous People Fluency Test in the Adult French-Quebec Population and Validation Study in Mild Cognitive Impairment and Alzheimer's Disease

OBJECTIVE

The production of words in verbal fluency tests relies heavily on executive functions and linguistic abilities. New tests such as the famous people fluency test can also be useful in clinical practice and research. This test, in which participants are asked to name so many famous people, has the potential to distinguish healthy individuals from participants with neurological disorders such as mild cognitive impairment or Alzheimer's disease.

METHOD

The aim of this study was to determine the psychometric validity of the test (Study 1) and to provide normative data in the adult population of French Quebec for the famous people fluency test (Study 2).

RESULTS

The results of the normative study, derived from a sample of 378 healthy individuals between the ages of 50 and 92, showed that age and educational level significantly influence performance on the test. Therefore, percentile ranks were calculated for performance on the famous people fluency test, stratified for these two variables. The results of Study 2 showed that the test differentiated the performance of healthy participants from the performance of participants with mild cognitive impairment or Alzheimer's disease. The results also showed that the famous people fluency test has adequate convergent validity, established with a semantic fluency test, and that the results showed good stability over time (test-retest validity).

CONCLUSION

Norms and psychometric data for the famous people fluency test will improve the ability of clinicians and researchers to better recognize executive and language impairments associated with pathological conditions.

Mini-SEA: Validity and Normative Data for the French-Quebec Population Aged 50 Years and Above

OBJECTIVE

The mini Social cognition & Emotional Assessment (mini-SEA) is a social cognition battery which assesses theory of mind and emotion recognition. Currently, no psychometrically validated measure of social cognition with adapted normative data exists for the middle-aged and elderly French-Quebec population. This project aims to determine the known-group discriminant validity of a cultural and linguistic adaptation of the mini-SEA between cognitively healthy people, those with mild cognitive impairment (MCI) or living with Alzheimer's Disease (AD). This study also aims to examine the stability of mini-SEA's performance over a 3-4-month time period, as well as to produce normative data for French-Quebec people aged 50 years. Normative data are derived for the full and an abbreviated version of the Faux Pas subtest.

METHOD

The sample included 211 French-speaking participants from Quebec (Canada) aged 50 to 89 years. Mini-SEA's performance between a sub-sample of cognitively healthy people (n = 20), those with MCI (n = 20) or with AD (n = 20) was compared. A sub-sample of cognitively healthy people (n = 30) performed the task twice to estimate test-retest reliability. Socio-demographic variables' effects on scores were examined to produce normative data in the form of regression equations or percentile ranks.

RESULTS

Significant differences emerged between cognitively healthy people and those with MCI or AD. Moreover, scores were relatively stable over a period of 3 to 4 months. Finally, for the normative data, age, gender, and education were associated with performance on the mini-SEA or its subtests.

CONCLUSIONS

This study improves and standardizes social cognition's assessment among French-Quebec individuals, which will help characterize their cognitive profile.

Normative Data for the Judgment of Line Orientation Test (Long and Short Forms) in the Quebec-French Population Aged between 50 and 89 Years

The Judgment of Line Orientation (JLO) Test of Benton assesses visuospatial processing without requiring motor skills. The test is frequently used in geriatric or brain-injured populations. As with other cognitive tests, performance on the JLO test may vary according to age, level of education, sex, and cultural background of individuals. The present study aimed to establish normative data for a short (15 items) and a long (30 items) form of the JLO. The sample for the short and long forms comprised 198 and 260 individuals, respectively, aged 50-89 years. All participants were French-speaking people from the province of Quebec, Canada. Using regression-based norming, the effects of age, years of formal education, and sex on JLO performance were estimated. The normative adjustment of the JLO short and long forms considered the weight of each predictor on test performance. Results indicated that JLO performance was positively associated with years of formal education and male sex, whereas it was negatively associated with age. Accordingly, normative data were generated using Z-scores and adjusted scaled scores derived from the regression equations. To conclude, the present norms will ease the detection of visuospatial impairment in French-Quebec middle-aged and older adults.

Translation and Adaptation of Cognistat in Hindi Language: For Computerized Evaluation of Cognitive Functioning

OBJECTIVE

Cognitive assessment is a crucial element of the mental health screening process. However, there is a lack of culturally appropriate cognitive screening tools for the Hindi-speaking aging population in India. We aimed to translate and culturally tailor the English version of the computerized Cognistat test for the Hindi-speaking aging population.

METHOD

The computer-based Cognistat Assessment System was culturally adapted for the North Indian Hindi-speaking population. Participants with mild cognitive impairment (MCI) (n = 30), depression (n = 30), and healthy control (n = 30) groups between the age range of 50 and 83 years were assessed using the translated version of the tool. The group differences were analyzed using analysis of variance, multivariate analysis of variance, Tukey's post hoc analysis for continuous variables, and Fisher's exact test for categorical variables. The correlation between the Cognistat domains was analyzed using Pearson's correlation, and test reliability was assessed using Cronbach's alpha.

RESULTS

The MCI group had significantly lower scores as compared with the depression and control groups on orientation, language, repetition, and calculation domain tasks. For attention and construction tasks, the MCI group had lower scores than the control group. MCI group scores were significantly lower than the control group on naming domain. The Hindi version of the test was reliable for the Hindi-speaking aging population.

CONCLUSIONS

Cognistat Hindi can be used by trained healthcare professionals with Hindi-speaking populations for culturally tailored primary evaluation of cognitive difficulties. Future research should focus on further validation and assessment of its properties.

Assessing Social Interaction and Loneliness and Their Association With Frailty Among Older Adults With Subjective Cognitive Decline or Mild Cognitive Impairment: Ecological Momentary Assessment Approach

BACKGROUND

Frail older adults are at greater risk of adverse health-related outcomes such as falls, disability, and mortality. Mild behavioral impairment (MBI), which is characterized by neurobehavioral symptoms in individuals without dementia, is a crucial factor in identifying at-risk groups and implementing early interventions for frail older adults. However, the specific role of social functioning, which encompasses social interaction and loneliness levels, in relation to frailty within this group remains unclear.

OBJECTIVE

This study investigated the association between frailty status, social interaction frequency, and loneliness levels among older adults with subjective cognitive decline (SCD) or mild cognitive impairment (MCI) while adjusting for MBI symptoms in 2 contexts: the presence and severity of MBI symptoms.

METHODS

Older adults with SCD or MCI were recruited from an outpatient clinic specializing in the early diagnosis and care management of dementia at a community health center, as well as from a community service center in Seoul, South Korea. Using an ecological momentary assessment approach, participants reported their daily social interaction frequency and loneliness level via a mobile app, 4 times daily for 2 weeks. Frailty status, the outcome variable, was assessed using the Korean version of the frailty phenotype questionnaire. Additionally, MBI symptoms were assessed using the 34-item MBI-Checklist covering 5 domains. Multinomial logistic regression analyses were performed to investigate the association between frailty status (robust, prefrail, and frail), and the independent variables, adjusting for the presence or severity of MBI symptoms.

RESULTS

Among the 101 participants analyzed, 29.7% (n=30) of participants were classified as prefrail, and 12.8% (n=13) of participants were classified as frail. Higher average daily social interaction scores were consistently associated with lower odds of a frail status compared to a robust status. This was evident in the models adjusted for both the global presence (relative risk ratio [RRR] 0.18, P=.02) and global severity (RRR 0.20, P=.02) of MBI symptoms.

CONCLUSIONS

Frequent social interaction was inversely associated with frail status in older adults with SCD or MCI, even after adjusting for the presence and severity of MBI symptoms. These findings highlight the potential of social functioning as a modifiable factor for addressing frailty among older adults at risk of cognitive and functional decline. Future prospective studies using real-time measurements are needed to refine these findings and further investigate additional risk factors and functional outcomes in this group.

Longitudinal deterioration of subjective cognitive decline in apolipoprotein ε4 carriers and improvement of subjective cognitive decline by multi-domain intervention for prevention of dementia: The cognitive function instrument assessment

BackgroundSubjective cognitive decline represents an early stage of mild cognitive impairment, with the Cognitive Function Instrument (CFI) serving to subjectively evaluate the decline in daily living activities associated with this minor cognitive decline.ObjectiveTo examine how CFI scores change with apolipoprotein E ε4 (ApoE4) carriage, objective cognitive decline, and dementia prevention intervention. We aimed to assess CFI's usefulness in the early dementia risk identification.MethodsThis study involved 196 older adults with normal cognition in a randomized controlled intervention trial. CFI was assessed every six months from baseline to 18 months, using the Alzheimer's Disease Cooperative Study-Preclinical Alzheimer Cognitive Composite (ADCS-PACC) to measure cognitive decline. We employed a mixed model for repeated measures to compare the CFI scores at 18 months in the ApoE4, ADCS-PACC, and allocation groups.ResultsCFI scores increased in ApoE4 carriers and decreased in the intervention group, with significant differences observed in the CFI score changes at 18 months between carriers and non-carriers and among the allocation groups (p = 0.002, p = 0.026, respectively). However, there was no significant difference in the CFI score change among ADCS-PACC groups (p = 0101).ConclusionsWe observed CFI scores worsening over time in individuals with ApoE4 and showing a tendency to deteriorate over time in those with objective cognitive decline. These findings suggest that the CFI may be able to identify high-risk individuals for dementia at an early stage. Furthermore, the improvement in the CFI score is considered a significant finding when considering future measures for subjective cognitive decline.

Blood biomarkers confirm subjective cognitive decline (SCD) as a distinct molecular and clinical stage within the NIA-AA framework of Alzheimer´s disease

Subjective cognitive decline (SCD) is proposed as an indicator of transitional disease stage 2 in the Alzheimer's disease (AD) continuum. However, molecular and particularly longitudinal fluid biomarker data for this stage are still limited. This study aimed to determine whether blood-based biomarkers in amyloid-positive individuals with SCD (A + SCD) support the notion of stage 2 as a distinct stage between stages 1 and 3 of AD and to identify those at high risk for clinical progression. In a prospective multicenter study (DELCODE) involving 457 participants across the AD continuum, we analyzed plasma phospho-tau 181 (p181) and neurofilament light chain (NfL) and assessed their association with longitudinal cognition, hippocampal atrophy, and AD clinical stage transition. The results showed that baseline plasma p181 levels were elevated and increased more rapidly in A + SCD individuals compared to amyloid-positive cognitively unimpaired (A + CU) individuals (stage 1). NfL levels rose across A + CU, A + SCD, and amyloid-positive mild cognitive impairment (A + MCI, stage 3). In A + SCD, but not in A + CU, higher p181 levels predicted cognitive decline (PACC5) and transition to MCI. In conclusion, plasma p181 provides molecular biomarker evidence supporting A + SCD as a pre-dementia AD stage (stage 2) distinct from A + CU (stage 1) and helps identify individuals at risk for cognitive decline early in the AD continuum.

Changes of EEG beta band power and functional connectivity during spaceflight: a retrospective study

Spaceflight exposes astronauts to unique conditions like microgravity, which may affect brain function, though it remains underexplored compared to other physiological systems. Astronauts often report temporary neurological symptoms, such as disorientation, visual disturbances, and motor issues, potentially linked to structural and electrophysiological brain changes. To investigate this, electroencephalography (EEG) is a reliable tool to study brain activity in space, measuring oscillatory activity and functional connectivity (FC). This study analyzed EEG data from five male astronauts during three stages: pre-flight, during low Earth orbit (LEO), and post-flight in a 2-min task-free eyes-closed (EC) condition followed by another 2-min of eyes-open (EO) condition. The focus was on beta band (12-30 Hz) activity, which is associated with motor control and proprioception. Results showed increased beta power during spaceflight when compared to pre-flight (EC: p < 0.01) and post-flight (EC: p < 0.01; EO: p < 0.05) conditions. FC strength also increased during spaceflight when compared to pre-flight (EO: p < 0.05) and post-flight (EC: p < 0.01; EO: p < 0.01) conditions. These differences were found primarily in the sensorimotor cortex (SMC) and frontotemporal regions, suggesting the brain's adaptation to altered vestibular and proprioceptive inputs during microgravity. As these results reflect astronaut's movement adaptation to microgravity, this study highlights the importance of understanding central nervous system (CNS) changes during spaceflights to ensure optimal performance and protect astronaut's health during long-duration missions.

Towards characterizing subjective cognitive decline in older adults

BackgroundSubjective cognitive decline (SCD), where older adults perceive a persistent decline of cognitive abilities without showing an objective cognitive impairment, may represent a preclinical stage of Alzheimer's disease (AD) in some individuals.ObjectiveThe complex characteristics of SCD cannot only be revealed by existing self-report questionnaires. Rather, it is necessary to involve individuals affected in the research process with methods like focus group discussions (FGDs).MethodsStudy conduction took place in three steps: telephone interview, neuropsychological assessment and questionnaires, four FGDs with 16 older adults (11 female, 5 male) affected by SCD. FGDs were analyzed with qualitative content analysis using an inductive - deductive code system.ResultsAlthough the neuropsychological assessments did not indicate a cognitive impairment, participants reported a decline for all cognitive domains within the FGDs, especially for the memory- and speech domain, with declining word-finding abilities as the most salient symptom. Participants reported strong concerns related to SCD and difficulties in social participation.ConclusionsSCD seems to go beyond age-related cognitive changes, but as individuals do not show an objective cognitive impairment (yet), their symptoms are often not taken seriously enough. The FGDs revealed information that questionnaires or neuropsychological tests do not capture. The gained insight into SCD symptoms, related coping strategies and concerns is important to be able to develop measures for identifying individuals at risk for a transition to AD and to develop intervention measures that aim at delaying a further decline and increasing the quality of life of individuals affected.

Enhanced associations between subjective cognitive concerns and blood-based AD biomarkers using a novel EMA approach

BACKGROUND

Subjective cognitive concerns (SCC) have emerged as important early indicators of Alzheimer's disease (AD) risk. Traditional measures of SCC rely on recall-based assessments, which may be limited in capturing real-time fluctuations in cognitive concerns. Ecological Momentary Assessment (EMA) offers a promising alternative by providing real-time data. This study aimed to link SCC assessed via EMA and traditional measures with blood-based AD biomarkers in a diverse, dementia-free, community-based sample based in the Bronx, NY.

METHODS

Einstein Aging Study (EAS) participants underwent in-person, recall-based assessments of SCC during an in-clinic visit. Additionally, EMA SCC assessments were collected once per day over two weeks. Linear regressions were conducted to examine the relationships between SCC variables and plasma biomarkers adjusted for demographics and mild cognitive impairment (MCI) status.

RESULTS

In N = 254 participants, EMA-reported SCCs demonstrated significant associations with AD biomarkers, particularly p-tau181 (β = 0.21, p = 0.001). Further, significant associations remain across both cognitive (cognitively unimpaired vs. MCI) and racial groups. In contrast, traditional SCC measures exhibited limited associations with these biomarkers. The findings highlight the added value of EMA in capturing SCCs that could indicate early ADRD risk.

CONCLUSIONS

EMA provides a more dynamic and potentially sensitive method for detecting early AD risk compared to traditional SCC assessments. These real-time measures could enhance early detection and clinical intervention, particularly in diverse and under-resourced populations. This study underscores the potential of EMA for broad applicability and inclusivity in monitoring AD progression and facilitating early therapeutic interventions.

Screening tools for subjective cognitive decline and mild cognitive impairment based on task-state prefrontal functional connectivity: a functional near-infrared spectroscopy study

BACKGROUND

Subjective cognitive decline (SCD) and mild cognitive impairment (MCI) carry the risk of progression to dementia, and accurate screening methods for these conditions are urgently needed. Studies have suggested the potential ability of functional near-infrared spectroscopy (fNIRS) to identify MCI and SCD. The present fNIRS study aimed to develop an early screening method for SCD and MCI based on activated prefrontal functional connectivity (FC) during the performance of cognitive scales and subject-wise cross-validation via machine learning.

METHODS

Activated prefrontal FC data measured by fNIRS were collected from 55 normal controls, 80 SCD patients, and 111 MCI patients. Differences in FC were analyzed among the groups, and FC strength and cognitive scale performance were extracted as features to build classification and predictive models through machine learning. Model performance was assessed based on accuracy, specificity, sensitivity, and area under the curve (AUC) with 95 % confidence interval (CI) values.

RESULTS

Statistical analysis revealed a trend toward more impaired prefrontal FC with declining cognitive function. Prediction models were built by combining features of prefrontal FC and cognitive scale performance and applying machine learning models, The models showed generally satisfactory abilities to differentiate among the three groups, especially those employing linear discriminant analysis, logistic regression, and support vector machine. Accuracies of 92.0 % for MCI vs. NC, 80.0 % for MCI vs. SCD, and 76.1 % for SCD vs. NC were achieved, and the highest AUC values were 97.0 % (95 % CI: 94.6 %-99.3 %) for MCI vs. NC, 87.0 % (95 % CI: 81.5 %-92.5 %) for MCI vs. SCD, and 79.2 % (95 % CI: 71.0 %-87.3 %) for SCD vs. NC.

CONCLUSION

The developed screening method based on fNIRS and machine learning has the potential to predict early-stage cognitive impairment based on prefrontal FC data collected during cognitive scale-induced activation.

Psychometric Properties of the Chinese Version of Everyday Cognition Scale (ECog) in Taiwanese Older Adults

BACKGROUND AND OBJECTIVES

The Everyday Cognition Scale (ECog) is widely employed for the subjective rating of functional activities of daily living in older adults. This study aimed to examine the psychometric properties of both informant-rated and self-rated ECog in Taiwanese older individuals to assess its applicability in this context.

RESEARCH DESIGN AND METHODS

A total of 1,166 subjects, including older adults (n = 583) and their primary caregivers or family members (n = 583), were recruited. Both self-rated and informant-rated ECog assessments were administered twice within a 1-month period. The study evaluated internal consistency, test-retest reliability, random measurement error, discriminative validity, construct validity, and concurrent validity using the Mini-Mental State Examination (MMSE) as a gold standard.

RESULTS

The informant-rated ECog demonstrated high internal consistency, acceptable to good test-retest reliability, small to moderate random measurement error, good discriminative validity, and moderate correlations with the MMSE. Additionally, a 7-factor model of the informant-rated ECog was supported. Conversely, the self-rated ECog exhibited high internal consistency, acceptable test-retest reliability, moderate to large random measurement error, adequate discriminative validity, and small correlations with the MMSE. Notably, only the domains of memory, verbal, planning, and organization were supported by a one-factor model.

DISCUSSION AND IMPLICATIONS

The psychometric properties of the informant-rated ECog surpassed those of the self-rated ECog. However, the self-rated ECog is recommended as a supplementary tool for assessing individuals' awareness of their cognitive function, particularly in the domain of memory.

Personalized brain models link cognitive decline progression to underlying synaptic and connectivity degeneration

Cognitive decline is a condition affecting almost one sixth of the elder population and is widely regarded as one of the first manifestations of Alzheimer's disease. Despite the extensive body of knowledge on the condition, there is no clear consensus on the structural defects and neurodegeneration processes determining cognitive decline evolution. Here, we introduce a Brain Network Model (BNM) simulating the effects of neurodegeneration on neural activity during cognitive processing. The model incorporates two key parameters accounting for distinct pathological mechanisms: synaptic degeneration, primarily leading to hyperexcitation, and brain disconnection. Through parameter optimization, we successfully replicated individual electroencephalography (EEG) responses recorded during task execution from 145 participants spanning different stages of cognitive decline. The cohort included healthy controls, patients with subjective cognitive decline (SCD), and those with mild cognitive impairment (MCI) of the Alzheimer type. Through model inversion, we generated personalized BNMs for each participant based on individual EEG recordings. These models revealed distinct network configurations corresponding to the patient's cognitive condition, with virtual neurodegeneration levels directly proportional to the severity of cognitive decline. Strikingly, the model uncovered a neurodegeneration-driven phase transition leading to two distinct regimes of neural activity underlying task execution. On either side of this phase transition, increasing synaptic degeneration induced changes in neural activity that closely mirrored experimental observations across cognitive decline stages. This enabled the model to directly link synaptic degeneration and hyperexcitation to cognitive decline severity. Furthermore, the model pinpointed posterior cingulum fiber degeneration as the structural driver of this phase transition. Our findings highlight the potential of BNMs to account for the evolution of neural activity across stages of cognitive decline while elucidating the underlying neurodegenerative mechanisms. This approach provides a novel framework for understanding how structural and functional brain alterations contribute to cognitive deterioration along the Alzheimer's continuum.

Loneliness and biomarkers of brain pathology in people with subjective cognitive decline

Loneliness is a neuropsychiatric symptom that has been associated with cognitive impairment and dementia. We aimed to investigate whether depressive symptomatology and biomarkers of Alzheimer's disease (AD) and cerebrovascular disease (CVD) are associated with loneliness. Secondly, we aimed to investigate whether loneliness, depressive symptomatology, and biomarkers of AD and CVD are associated with subjective cognitive decline (SCD). We included 215 cognitively unimpaired participants (70 y/o) with cerebrospinal fluid biomarkers, magnetic resonance imaging, and questionnaires for loneliness, depressive symptomatology, and SCD. For aim 1, our findings showed that CVD and depressive symptomatology were the most relevant measures to discriminate people with loneliness. For aim 2, a random forest classification model showed that loneliness contributed to discriminate individuals with SCD, but logistic regression showed that its partial predictive effect was non-significant when depressive symptomatology and AD biomarkers were included in the models. We conclude that loneliness is associated with SCD, CVD, and depressive symptomatology. Given the complex interplay between loneliness, depressive symptomatology, and SCD, more research is needed to fully clarify the unique role of each neuropsychiatric symptom in relation to biomarkers of brain pathology.

Reliability of online, remote neuropsychological assessment in people with and without subjective cognitive decline

Online, remote neuropsychological assessment paradigms may offer a cost-effective alternative to in-person assessment for people who experience subjective cognitive decline (SCD). However, it is vital to establish the psychometric properties of such paradigms. The present study (i) evaluates test-retest reliability of remote, online neuropsychological tests from the NeurOn software platform in people with and without SCD (Non-SCD) recruited from the general population; and (ii) investigates potential group differences in baseline performance and longitudinal change. Ninety-nine participants (SCD N = 44, Non-SCD N = 55) completed seven tests from the NeurOn battery, covering visual and verbal memory, working memory, attention and psychomotor speed. Sixty-nine participants (SCD N = 34, Non-SCD N = 35) repeated the assessment six (+/- one) months later. SCD was classified using the Cognitive Change Index questionnaire. Test-retest reliability of the NeurOn test outcome measures ranged from poor to good, with the strongest evidence of reliability shown for the Sustained Attention to Response Test and Picture Recognition. The SCD group was significantly older than the Non-SCD group so group differences were investigated using analysis of covariance whilst controlling for the effect of age. SCD scored significantly better than Non-SCD for Digit Span Backwards (maximum sequence length) and Picture Recognition (recall of object position) at baseline. However, these were not significant when using the Bonferroni-adjusted alpha level. There were no differences between SCD and Non-SCD in longitudinal change. The results suggest online, remote neuropsychological assessment is a promising option for assessing and monitoring SCD, however more research is needed to determine the most suitable tests in terms of reliability and sensitivity to SCD.

Silibinin's role in counteracting neuronal apoptosis and synaptic dysfunction in Alzheimer's disease models

This study investigates silibinin's capacity to mitigate Alzheimer's disease (AD) pathologies with a particular emphasis on its effects on apoptosis and synaptic dysfunction in AD models. Employing APP/PS1 transgenic mice and SH-SY5Y neuroblastoma cell lines, our research assessed the efficacy of silibinin in reducing amyloid-beta (Aβ) deposition, neuroinflammation, and neuronal apoptosis. Our results demonstrate that silibinin significantly decreases Aβ accumulation and neuroinflammation and robustly inhibits apoptosis in neuronal cells. Additionally, silibinin enhances the expression of synaptic proteins, thereby supporting synaptic integrity. Through network pharmacology analysis, we identified potential targets of silibinin in Aβ metabolism and synaptic functions. Mechanistically, our findings suggest that silibinin promotes neuronal survival predominantly via the modulation of the Fyn/GluN2B/CaMKIIα signaling pathway, which protects against Aβ1-42-induced apoptosis. These insights highlight silibinin's potential as a therapeutic agent for AD, particularly its role in reducing neuronal apoptosis and maintaining synaptic function.

Associations between adverse childhood experiences and subjective cognitive decline: A scoping review

BACKGROUND

Long-term health effects of adverse childhood experiences (ACEs) include cognitive decline that occurs later in life. Subjective cognitive decline (SCD), recognized as an early indicator of Alzheimer's disease, may present an essential period for intervention in populations with ACEs.

OBJECTIVE

This review aims to explore the associations between ACEs and SCD, while examining the potential moderating effects of sociodemographic factors METHODS: A systematic search of four databases (Medline, PsycINFO, CINAHL, and Web of Science) was conducted from inception to July 2024. Eligible studies included adults with a history of ACEs and self-reported SCD. In total, twelve studies were included, primarily using U.S.-based samples, with sample sizes ranging from 46 to over 195,000 participants.

RESULTS

The evidence of a dose-response relationship highlights the link between ACEs and SCD. The risk of SCD increases among adults over 65, lower-income groups, and sexual minorities. However, gender differences were inconsistently observed across studies. Mental health conditions, particularly depression is a significant risk factor.

CONCLUSIONS

Early screening and intervention for SCD among individuals with high ACE exposure may help delay the progression to severe cognitive impairment. However, the reliance on cross-sectional studies and high risk of bias limit causal inferences. Future research should explore longitudinal studies with diverse populations to clarify causal pathways and the role of sociodemographic factors in the ACE-SCD relationship.

Characterization of subclinical depressive and anxiety symptoms in older adults with subjective cognitive decline progressing to objective cognitive impairment: A prospective 4-year follow-up study

BackgroundSubjective cognitive decline (SCD) is linked to a more rapid progression to the development of mild cognitive impairment (MCI) or Alzheimer's disease (AD). SCD has been correlated with affective symptoms such as depression and anxiety. Recent research aimed to shed light on the relationship between these affective symptoms and how they might correlate to a more rapid progression to objective cognitive impairment. No studies have assessed the presence, type, and intensity of depressive and anxiety symptoms between SCD individuals who progressed versus those who did not.ObjectiveThis study aimed to establish whether there are differences between subclinical depressive and anxiety symptoms in terms of presence, type, and intensity of symptoms presented by individuals with SCD who progressed to an objective cognitive decline.MethodsThe recruited participants originated from the Consortium for the Early Identification of Alzheimer's Disease - Québec (CIMA-Q) cohort. They were assessed twice, with an interval of 4 years separating the evaluations. Anxiety symptoms were assessed using the Geriatric Anxiety Inventory (GAI) and depression symptoms using the Geriatric Depression Scale (GDS-30).ResultsThe presence, type and intensity of anxiety symptoms did not significantly distinguish the two groups. Only one type of hopelessness-related depressive symptom was significantly higher in SCD participants who had progressed to objective cognitive decline compared with those who had not.ConclusionsOur results suggest that it may be beneficial to target hopelessness in non-pharmacological interventions aimed at preventing the progression of people with SCD to MCI or AD.

Dynamic Functional Network Connectivity Pattern of the Amygdalohippocampal Complex in Individuals With Subjective Cognitive Decline

Subjective cognitive decline (SCD) is a potential early marker of cognitive decline and dementia. The amygdalohippocampal structure and function are closely related to cognitive decline, but few studies have investigated large-scale amygdalohippocampal brain functional network connectivity in individuals with SCD. Here, we aim to explore how the dynamic functional network connectivity (dFNC) between the amygdalohippocampal complex and other brain networks contributes to the understanding of early cognitive decline. Independent component analysis (ICA) and dFNC analysis were applied to functional magnetic resonance imaging (fMRI) data from 66 individuals with SCD to extract the amygdalohippocampal complex and identify distinct connectivity states. Cognitive performance was assessed through a composite Z score derived from a battery of neuropsychological tests. Correlation analyses were performed to examine the associations between the dFNC patterns and cognitive performance. Three distinct dFNC states were identified, each characterized by varying levels of within- and inter-network connectivity, with occurrences of 65%, 18%, and 17% respectively. Cognitive function, measured using a composite Z score, was positively correlated with amygdalohippocampal-sensorimotor network (SM) and amygdalohippocampal-visual network (VI) dFNC in State 2. Significant correlations were observed between the amygdalohippocampal complex and the left precentral gyrus (r = 0.517, FDR-corrected p = 0.005), postcentral gyrus (r = 0.487, FDR-corrected p = 0.034), and multiple visual network regions, including the lingual gyrus and lateral occipital cortex (all Ps < 0.05, FDR-corrected). These associations remained significant after adjusting for sex and age. These findings extend the current understanding of amygdalohippocampal dysfunction in cognitive decline and demonstrate that cognitive function is associated with distinct large-scale amygdalohippocampal network dynamics.

Cancer Survivorship and Subjective Cognitive Decline in the United States

PURPOSE

Studies examining the link between cancer survivorship and subjective cognitive decline (SCD) are lacking. Therefore, the current study aimed to determine the association between cancer survivorship and SCD among a nationally representative sample of middle-aged and older adults.

METHOD

Data were obtained from the 2021 Behavioral Risk Factor Surveillance System Survey. Crude and adjusted logistic regression models, controlling for age, gender, race/ethnicity, educational level, income, and work status, were used to determine the association between cancer survivorship characteristics and SCD.

RESULTS

Respondents who were currently undergoing treatment had 86% higher odds of SCD (adjusted odds ratio [aOR] = 1.86; 95% confidence interval [CI] [1.06, 3.27]) compared to respondents who completed treatment. However, those who refused treatment were less likely to report SCD (aOR = 0.006; 95% CI [<0.001, 0.059]) compared to respondents who completed treatment.

CONCLUSION

Cognition interventions may be helpful for individuals diagnosed with cancer who are undergoing treatment, middle-aged, and have not started treatment. [Journal of Gerontological Nursing, 51(4), 12-18.].

Using machine learning models to identify severe subjective cognitive decline and related factors in nurses during the menopause transition: a pilot study

OBJECTIVE

This study aims to develop and validate a machine learning model for identifying individuals within the nursing population experiencing severe subjective cognitive decline (SCD) during the menopause transition, along with their associated factors.

METHODS

A secondary analysis was performed using cross-sectional data from 1,264 nurses undergoing the menopause transition. The data set was randomly split into training (75%) and validation sets (25%), with the Bortua algorithm employed for feature selection. Seven machine learning models were constructed and optimized. Model performance was assessed using area under the receiver operating characteristic curve, accuracy, sensitivity, specificity, and F1 score. Shapley Additive Explanations analysis was used to elucidate the weights and characteristics of various factors associated with severe SCD.

RESULTS

The average SCD score among nurses in the menopause transition was (5.38 ± 2.43). The Bortua algorithm identified 13 significant feature factors. Among the seven models, the support vector machine exhibited the best overall performance, achieving an area under the receiver operating characteristic curve of 0.846, accuracy of 0.789, sensitivity of 0.753, specificity of 0.802, and an F1 score of 0.658. The two variables most strongly associated with SCD were menopausal symptoms and the stage of menopause.

CONCLUSIONS

The machine learning models effectively identify individuals with severe SCD and the related factors associated with severe SCD in nurses during the menopause transition. These findings offer valuable insights for the management of cognitive health in women undergoing the menopause transition.

Risk Factors for Poor Sleep Quality and Subjective Cognitive Decline in Older Adults Living in the United States During the COVID-19 Pandemic

BACKGROUND/OBJECTIVES

Poor sleep quality, depression, and anxiety are associated with subjective cognitive decline (SCD) and greater risk for developing cognitive impairment and Alzheimer's disease. The COVID-19 pandemic negatively impacted sleep habits and psychological well-being in many individuals, yet their relationship to SCD in this context remains understudied. We examined sociodemographic characteristics, depression, anxiety, and sleep changes during the pandemic (i.e., increased problems/poorer quality) and SCD in older individuals living in the US.

METHODS

In total, 288 older adults (Mage = 67.4 [7.4]) completed an online survey including a sociodemographic questionnaire, the Center for Epidemiologic Studies Depression Scale (Revised) (CES-D-10; depression), General Anxiety Disorder-7 (GAD-7; anxiety), the Everyday Cognition scale (ECog; SCD), and a question about increased sleep problems/worsened sleep quality during the pandemic. Hierarchical and logistic regression analyses were used to assess relations among sociodemographic factors, depression, anxiety, changes in sleep quality, and SCD.

RESULTS

Self-reported pandemic-related impairments in sleep were associated with greater SCD (β = 0.16, p = 0.01). Depression (β = 0.46, p < 0.001) and anxiety (β = 0.29, p < 0.001) were also associated with greater SCD. Depression (OR = 1.17, p < 0.001) and anxiety (OR = 1.15, p = 0.017) predicted reported poorer sleep during the pandemic.

CONCLUSIONS

Depression, anxiety, and poorer sleep quality during the COVID-19 pandemic were associated with greater SCD concerns. Greater depression and anxiety were also associated with the reported sleep problems/worsened sleep quality. Prevention and management of anxiety and depressive symptoms may help maintain sleep quality and reduce risk of cognitive decline.

Pilot study of the Greek Interventional Geriatric Initiative to Prevent Cognitive Impairment and Disability in individuals with subjective cognitive decline: paving the way towards brain health clinics in Greece

The pilot phase of the Greek Interventional Geriatric Initiative to Prevent Cognitive Impairment and Disability (GINGER) aims to assess the feasibility of a multi-level dementia risk reduction intervention in individuals with subjective cognitive decline (SCD) over a six-month period. The study design incorporates a comprehensive set of trans-disciplinary assessments and interventions in multiple centers across Greece. Individuals 55 years or older with subjective cognitive complaints who do not fulfill criteria for either mild cognitive impairment or dementia are screened for dementia risk factors in the following domains: nutrition, physical activities, vision and hearing, vascular and metabolic parameters, anxiety and depressive symptoms, and insomnia. All GINGER participants receive a cognitive empowerment intervention. Using a precision medicine approach, they receive up to three additional domain-specific interventions based on their individual risk factor profiles. Changes in cognition, dementia risk factors, quality of life and other measures compared to baseline are assessed at three- and six months after the initiation of the intervention. The GINGER protocol was designed and is run by a multi-disciplinary team of dieticians, neurologists, psychiatrists, psychologists, and physiotherapists, while computer scientists oversee data management. The objectives of this pilot phase are (i) evaluation of the protocol's feasibility, (ii) assessment of intervention effects on the individual risk domains targeted by the interventions, (iii) estimation of the overall effects of the intervention on cognitive function, dementia risk and quality of life. The GINGER findings will provide a solid foundation for paving the way towards a network of evidence-based brain health clinics in Greece.

Disease stage-specific atrophy markers in Alzheimer's disease

INTRODUCTION

Structural MRI often lacks diagnostic, prognostic, and monitoring value in Alzheimer's disease (AD), particularly in early disease stages. To improve its utility, we aimed to identify optimal MRI readouts for different use cases.

METHODS

We included 363 older adults; healthy controls (HC) who were negative or positive for amyloidbeta (Aβ) and Aβ-positive patients with subjective cognitive decline (SCD), mild cognitive impairment, or dementia of the Alzheimer type. MRI and neuropsychological assessments were administered annually for up to three years.

RESULTS

Accelerated atrophy of distinct MTL subregions was evident already during preclinical AD. Symptomatic disease stages most notably differed in their hippocampal and parietal atrophy signatures. Associations of atrophy markers and cognitive inventories varied by intended use and disease stage.

DISCUSSION

With the appropriate readout, MRI can detect abnormal atrophy already during preclinical AD. To optimize performance, MRI readouts should be tailored to the targeted disease stage and intended use.

Electroencephalographic Biomarkers for Neuropsychiatric Diseases: The State of the Art

Because of their nature, biomarkers for neuropsychiatric diseases were out of the reach of medical diagnostic technology until the past few decades. In recent years, the confluence of greater, affordable computer power with the need for more efficient diagnoses and treatments has increased interest in and the possibility of their discovery. This review will focus on the progress made over the past ten years regarding the search for electroencephalographic biomarkers for neuropsychiatric diseases. This includes algorithms and methods of analysis, machine learning, and quantitative electroencephalography as applied to neurodegenerative and neurodevelopmental diseases as well as traumatic brain injury and COVID-19. Our findings suggest that there is a need for consensus among quantitative electroencephalography researchers on the classification of biomarkers that most suit this field; that there is a slight disconnection between the development of increasingly sophisticated methods of analysis and what they will actually be of use for in the clinical setting; and finally, that diagnostic biomarkers are the most favored type in the field with a few caveats. The main goal of this state-of-the-art review is to provide the reader with a general panorama of the state of the art in this field.

Association between periodontal disease and age-related cognitive impairment: a narrative review

BACKGROUND

Previous studies have shown associations between periodontal disease and age-related cognitive impairment. However, little is known about the different cognitive functions that may be affected in patients with periodontal disease.

METHODS

We reviewed the recent literature to better understand the bidirectional relationship between cognitive function and periodontal disease, and to explore the cognitive assessments that may be useful when investigating this relationship. We also reviewed the literature around improving periodontal health in older adults presenting with cognitive impairment, which may improve their cognition.

RESULTS

There is a bidirectional relationship between periodontal disease and cognitive impairment. We also found that visuospatial function, attention, memory, and language are important cognitive domains that may be impaired in older people with periodontal disease, possibly because these factors are associated with the ability to adequately brush one's teeth. Furthermore, we noted that the choice of cognitive assessment may be particularly important when studying cognitive function in relation to periodontal health. To improve periodontal health in older people with cognitive impairment, partner-assisted interventions, adequate toothbrushing, and the use of a powered toothbrush have all been proposed. The early initiation of regular oral care visits, education for individuals, improving cooking skills, and dietary/caloric restrictions may also contribute to improving periodontal health.

CONCLUSIONS

The bidirectional nature of the relationship between periodontal health and cognitive function is important for older adults presenting with cognitive impairment. Furthermore, improvements in periodontal health may help to improve cognitive impairment. The appropriate assessment of cognitive function will contribute to preserving and improving oral health in older people with periodontal disease.

Brain fog

'Brain fog' is a term that patients use increasingly frequently in the neurology clinic. We may think that we know what patients are talking about but at least some of the time we are likely to be getting it wrong. Patients use the term 'brain fog' to describe a wide range of subjective phenomena and symptoms. This paper suggests useful lines of questioning, and discusses the clinical correlates of a range of common 'brain fog' experiences.

Cognitive Performance Among Older Adults with Subjective Cognitive Decline

Objectives: The main objective of this cross-sectional study was to investigate if there are significant differences in cognition between a group of older adults with subjective cognitive decline (SCD) and cognitively intact controls. Methods: An initial sample of 132 older people underwent an extensive neuropsychological evaluation (memory, executive functions, and language) and were classified according to diagnostic criteria. Two groups of 33 subjects each, controls and SCD, were formed using an a priori case-matching procedures in different variables: age, biological sex, years of education, cognitive reserve, and Mini-Mental State Exam. Results: The mean age and standard deviation in the control group were equal to 70.39 ± 4.31 years, while in the SCD group, they were 70.30 ± 4.33 years. The number of males (n = 9) and females (n = 24) was equal in both groups; the means of years of education were also quite similar. SCD participants have a significantly lower mood than the controls. Significant differences between groups were obtained in delayed recall, inhibitory control, and comprehension of sentences not fitted to canonical word order in Spanish. A logistic regression revealed that a lower score on the Stroop's interference condition is associated with a higher likelihood of having SCD. Finally, ROC analysis provided a model that performs better than random chance, and a cut-off score in Stroop's interference condition equal to 49 was suggested for clinically differentiating the two groups. Conclusions: This study highlights that, compared to a matched control group, participants with SCD showed subtle but significant neuropsychological differences.

Knowledge domain and emerging trends in post-stroke cognitive impairment: a bibliometric analysis

Background

Cognitive impairment is an important cause of disability and death among the elderly. One of the most important risk factors is stroke. Post-stroke cognitive impairment (PSCI) not only diminishes the quality of life for patients but also increases the burden on families and society. But PSCI can be mitigated through early intervention. Cerebral small vessel disease (CSVD) is one of the significant causes of stroke and has garnered considerable attention in PSCI. Therefore, this study aims to identify research priorities and trends in PSCI through bibliometric analysis, and further explore the role played by CSVD in PSCI.

Methods

In this study, we performed a systematic search in the Science Citation Index Expanded (SCI-E) of the Web of Science Core Collection (WoSCC). VOSviewer, CiteSpace and Origin were mainly used to visualize the research focus and trend in PSCI. In addition, we screened the retrieved literature again, and performed keyword analysis on the studies related to CSVD.

Results

A total of 1,943 publications were retrieved in the field of PSCI in this study, with consistent upward trend in annual publications in recent years. Pendlebury was an important leader in PSCI research. Capital Medical University was in the leading position judging from the number of publications. China had the highest number of publications in this field. The journal Stroke had the strongest international influence in this field. Keywords such as "functional connectivity," "tool," "systematic review," and "meta-analysis" have been revealed to have momentous impact on PSCI in recent years. In the further analysis of PSCI and CSVD, "hypertension," "white matter hyperintensities (WMH)," "cerebral microbleeds (CMBs)," and "cerebral amyloid angiopathy (CAA)" received extensive attention.

Conclusion

The study of PSCI is still in the development stage. This study systematically summarizes the progress and development trend in the field of PSCI, and further explores the relationship between CSVD and PSCI through hypertension and magnetic resonance imaging markers. This study is of great significance for researchers to quickly understand the development of PSCI, but also helps them understand future directions, and provides important insights for the prevention and treatment of PSCI.