Affective symptoms and risk of progression to mild cognitive impairment or dementia in subjective cognitive decline: A systematic review and meta-analysis

Cognitive training for Alzheimer's disease and other forms of dementia: Insights from a systematic review and Bayesian meta-analysis

BackgroundThe prevalence of individuals living with mild cognitive impairment (MCI), Alzheimer's disease (AD), and other forms of dementia is globally increasing. Four out of nine international clinical guidelines recommend non-pharmacological cognitive interventions to enhance cognition, independence, and wellbeing. However, the effectiveness of cognitive rehabilitation (CR) and cognitive training (CT) for individuals with MCI and AD and other forms of dementia is still debatable, often due to significant heterogeneity among studies.ObjectiveThis study aims to assess the effectiveness of CT and CR in these populations.MethodsFollowing PRISMA guidelines, we conducted a comprehensive literature search across databases including OVID, MEDLINE, EMBASE, and Scopus, identifying randomized controlled trials and non-randomized pre-post intervention studies. The Bayesian meta-analysis focused on pre-post changes in global cognition, quality of life, everyday functioning, and depression, avoiding comparisons with control groups to reduce heterogeneity (PROSPERO: CRD42022365038).ResultsThe search yielded 6075 results, with 40 studies meeting inclusion criteria, encompassing 50 independent trials. CT and people with AD and other dementias are the best represented intervention and population, respectively. CT was more effective in improving global cognition in individuals with AD and other dementias, and paper-and-pencil and face-to-face formats yielded greater benefits. The analysis showed a significant susceptibility to bias among the studies.ConclusionsLimitations in outcome measure (e.g., MMSE) suggest the need for more sensitive assessments, especially for MCI. Future research should explore broader aspects of wellbeing and investigate the potential of CR. Policymakers are encouraged to consider these findings when designing cognitive interventions for this population.

[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.

Prevalence and related factors of physical function and cognitive impairment among older adults: a population-based regional cross-sectional study

Background and aims

As the country with the largest and fastest-aging older population worldwide, China has hosted an increasing number of regional investigations into disability among older adults. However, the prevalence of disabilities related to physical function and cognition in southern China remains unknown. This study aimed to assess the prevalence of and associated factors for cognitive and physical function impairment in individuals aged 60 years and older.

Methods

For this population-based cross-sectional study, a total of 5,603 participants were recruited between June 2021 and December 2022 using a multistage, stratified, cluster sampling procedure. Instruments, including a general questionnaire, basic and instrumental activities of daily living, the Chinese version of the Mini-Mental State Examination (MMSE), the Patient Health Questionnaire-9 (PHQ-9), and the Generalized Anxiety Disorder-7 (GAD-7), were used to collect data through a WeChat mini program. Binary and multivariate logistic regression analyses were applied to explore the influencing factors.

Results

The prevalence of physical function and cognitive impairment among older adults was 37.3 and 31.0%, respectively. Multivariate regression analyses revealed that age, family income, education level, place of residence, medication type, annual physical examinations, weekly social activities, support from family or friends, hearing disorders, walking disorders, and depression were all associated with both physical function and cognitive impairment. Moreover, an increased risk of physical function impairment correlated with BMI, region, income source, smoking, and weekly exercise, while cognitive impairment was associated with the number of children, insurance type, coronary heart disease, and anxiety. Physical function (OR: 1.79, 95% CI: 1.49-2.16) and cognitive impairment (OR: 1.83, 95% CI: 1.51-2.21) were mutually influential in our study.

Conclusion

This study showed a high prevalence of various factors related to physical function and cognitive impairment. The results revealed that comprehensive and systematic prevention and control programs for disabilities should be developed to improve the quality of life for older adults.

Personality and neuropsychiatric symptoms in individuals diagnosed with long COVID

OBJECTIVE

This study investigates persistent physical and neuropsychiatric symptoms in Long COVID, focusing on their severity and assessing risk/resilience factors, including conscientiousness and neuroticism. The study utilizes a mediation model to explore the potential role of psychological distress in mediating its impact on cognitive decline.

METHODS

In an online survey, 114 participants diagnosed with Long COVID completed assessments, including the Patient Health Questionnaire (PHQ-9) and Generalized Anxiety Disorder (GAD-7) for psychological distress, Subjective Cognitive Decline (SCD) questionnaire for cognitive decline, Pittsburgh Sleep Quality Index (PSQI) for sleep disorders, and Multidimensional Scale of Perceived Social Support (MSPSS) with "BIG-5 inventory" subscales for risk/resilience factors.

RESULTS

Findings showed high rates of depressive disorders (45.6%), generalized anxiety disorders (21%), sleep disturbances (76.3%), and reported cognitive changes (94.7%). Conscientiousness negatively correlated with psychological distress (p < .001, r = - .48) and cognitive decline (p < .001, r = - .36), while neuroticism positively correlated (p < .001, r = .62 and p < .001, r = .41, respectively). Social support negatively correlated with psychological distress (p < .001, r = - .52) and cognitive decline (p < .001, r = - .41). Psychological distress fully mediated personality traits and cognitive decline correlations, with significant full mediation for neuroticism [95% CI = (0.22, 0.48)] and conscientiousness [95% CI = (-0.33, -0.07)], controlling for age, gender, other chronic morbidity and social support.

CONCLUSION

The study underscores the significance of incorporating psychological interventions into treatment plans to alleviate distress symptoms associated with cognitive decline in conditions like Long COVID.

Prevalence and influencing factors of cognitive frailty among Chinese older adults: A systematic review and meta-analysis

AIMS

Cognitive frailty refers to the coexistence of physical frailty and cognitive impairment in older adults, without a concurrent diagnosis of Alzheimer's disease or other dementias. This review aims to evaluate the prevalence of CF subtypes and identify influencing factors among Chinese older adults.

METHODS

The following databases were searched: PubMed/Medline, Embase, Cochrane Library, WOS, PsycINFO and CNKI et al (1 January 2001 to 20 October 2022). The risk of bias was assessed using the Agency for Healthcare Research and Quality Evidence-based Practice Center Methods Guide. Stata 17.0 software was used to pool the prevalence of cognitive frailty, and the pooled odds ratio and 95% CI of the influencing factors were calculated.

RESULTS

The meta-analysis (56 studies and 80,320 participants) revealed the following prevalence rates: CF (18.9%), reversible CF (19.5%), potentially reversible CF (17.5%), CF in community-dwelling older adults (14.3%), CF in nursing homes (22.7%) and CF in older inpatients (25.2%). Influential factors identified included age, gender, education, nutrition, depression, exercise, sleep and comorbidity.

CONCLUSIONS

The prevalence of CF among Chinese older adults is notably high, and it probably underestimates the prevalence of reversible cognitive frailty. It is crucial to encourage adherence to healthy behaviours, as it can effectively reduce and delay the onset of cognitive frailty.

Relationship of subjective and objective cognition with post-stroke mood differs between early and long-term stroke

Objective: Depression and anxiety affects approximately 1 in 3 stroke survivors. Performance on standardized objective cognitive tests and self-reported subjective cognitive symptoms are associated with concurrent depression and anxiety, but longitudinal data on whether and how objective and subjective cognition relate to emotional outcomes are lacking. Method: N = 99 stroke survivors (M age = 68.9, SD = 13.1; Median NIH Stroke Severity = 5) completed measures of depression and anxiety (Hospital Anxiety and Depression Scale; HADS), objective cognition (Oxford Cognitive Screen) and subjective cognitive symptoms (Cognitive Failures Questionnaire) at 6-months, 4.5, and 5.5 years post-stroke. The contribution of objective and subjective cognition to depression and anxiety was determined via mixed-effects models. Results: We found no evidence that age, stroke severity, years of education, and participant sex related to changes in HADS-Depression or HADS-Anxiety scores (Marginal R2=0.03 and 0.05, respectively). Objective cognitive impairments at 6-months and increases in subjective cognitive symptoms at 5.5 years significantly related to increased HADS-Depression scores (Marginal R2=0.22). Only increases in subjective cognitive symptoms at 5.5 years significantly related to increased HADS-Anxiety scores (Marginal R2=0.20). When conducting models in reverse, HADS-Depression and HADS-Anxiety scores did not reciprocally explain changes in subjective cognitive symptoms. Conclusions: Objective cognitive abilities are more strongly associated with depression at 6-months post-stroke, while subjective cognitive symptoms are more relevant to both long-term post-stroke depression and anxiety. There may be a unique unidirectional influence of subjective cognitive symptoms to post-stroke depression and anxiety.

Neuropsychiatric symptoms and metamemory across the life span: psychometric properties of the German Multifactorial Memory Questionnaire (MMQ)

OBJECTIVE

We assessed the psychometric properties, established normative data for the German Multifactorial Memory Questionnaire (MMQ), and analyzed its association with neuropsychiatric factors across the life span to provide a validated metamemory assessment for a German-speaking population.

METHODS

The three MMQ scales (memory satisfaction, self-rated ability, and strategy application) were translated into German, considering cultural, linguistic, and conceptual aspects. To validate the MMQ and assess associations with neuropsychiatric factors, the Complainer Profile Identification, Geriatric Depression Scale, Beck Anxiety Inventory, Pittsburgh Sleep Quality Index, and Short-Form-Health Survey were applied in an online study in 336 healthy participants with follow-up after 8 months.

RESULTS

Psychometric evaluation of the German MMQ showed normal distribution of all scales and good to excellent validity, internal consistency, and retest reliability. We provide percentiles and normative data for z-score conversion. Importantly, even subclinically elevated scores in depressiveness and anxiety were associated with decreased memory satisfaction and self-rated ability. Furthermore, although the influence of age on the German MMQ scales was minimal, effects of neuropsychiatric factors such as sleep quality, anxiety, and depressiveness on MMQ Satisfaction and Ability varied across the life span.

CONCLUSIONS

Our study provides a validated German translation of the MMQ with normative data and reliability measures, including reliable change scores. We show the impact of neuropsychiatric factors on the MMQ scales across the life span and emphasize the relevance of a multifactorial approach to metamemory as a measure of individualized everyday functionality and the importance of including neuropsychiatric factors into both research and clinical assessments of metamemory.

Progress on early diagnosing Alzheimer's disease

Alzheimer's disease (AD) is a progressive neurodegenerative disorder that affects both cognition and non-cognition functions. The disease follows a continuum, starting with preclinical stages, progressing to mild cognitive and behavioral impairment, ultimately leading to dementia. Early detection of AD is crucial for better diagnosis and more effective treatment. However, the current AD diagnostic tests of biomarkers using cerebrospinal fluid and/or brain imaging are invasive or expensive, and mostly are still not able to detect early disease state. Consequently, there is an urgent need to develop new diagnostic techniques with higher sensitivity and specificity during the preclinical stages of AD. Various non-cognitive manifestations, including behavioral abnormalities, sleep disturbances, sensory dysfunctions, and physical changes, have been observed in the preclinical AD stage before occurrence of notable cognitive decline. Recent research advances have identified several biofluid biomarkers as early indicators of AD. This review focuses on these non-cognitive changes and newly discovered biomarkers in AD, specifically addressing the preclinical stages of the disease. Furthermore, it is of importance to explore the potential for developing a predictive system or network to forecast disease onset and progression at the early stage of AD.

Clinical predictors of Alzheimer's disease-like brain atrophy in individuals with memory complaints

OBJECTIVES

The definition and assessment methods for subjective cognitive decline (SCD) vary among studies. We aimed to investigate which features or assessment methods of SCD best predict Alzheimer's disease (AD)-related structural atrophy patterns.

METHODS

We assessed 104 individuals aged 55+ with memory complaints but normal cognitive screening. Our research questions were as follows: To improve the prediction of AD related morphological changes, (1) Would the use of a standardized cognitive screening scale be beneficial? (2) Is conducting a thorough neuropsychological evaluation necessary instead of relying solely on cognitive screening tests? (3) Should we apply SCD-plus research criteria, and if so, which criterion would be the most effective? (4) Is it necessary to consider medical and psychiatric comorbidities, vitamin deficiencies, vascular burden on MRI, and family history? We utilized Freesurfer to analyze cortical thickness and regional brain volume meta-scores linked to AD or predicting its development. We employed multiple linear regression models for each variable, with morphology as the dependent variable.

RESULTS

AD-like morphology was associated with subjective complaints in males, individuals with advanced age, and higher education. Later age of onset for complaints, complaints specifically related to memory, excessive deep white matter vascular lesions, and using medications that have negative implications for cognitive health (according to the Beers criteria) were predictive of AD-related morphology. The subjective cognitive memory questionnaire scores were found to be a better predictor of reduced volumes than a single-question assessment. It is important to note that not all SCD-plus criteria were evaluated in this study, particularly the APOE genotype, amyloid, and tau status, due to resource limitations.

CONCLUSIONS

The detection of AD-related structural changes is impacted by demographics and assessment methods. Standardizing SCD assessment methods can enhance predictive accuracy.

Impaired lexical access for unique entities in individuals with subjective cognitive decline

Subjective cognitive decline (SCD) may serve as an early indicator of Alzheimer's disease (AD). However, accurately quantifying cognitive impairment in SCD is challenging, mainly because existing assessment tools lack sensitivity. This study examined how tasks specifically designed to assess knowledge of famous people, could potentially aid in identifying cognitive impairment in SCD. A total of 60 adults with SCD and 60 healthy controls (HCs) aged 50 to 82 years performed a famous people verbal fluency task and a famous people naming task. In the famous people fluency task, the results showed that the individuals with SCD produced significantly fewer famous names in the total time allowed than the HCs, and this difference was also found in the first and the second time interval. In the famous people naming task, the performance of the SCD group was significantly lower than that of the HC group only in the more recent period of fame. Overall, these results suggest that retrieving the names of famous people was more difficult for people with SCD than for people without cognitive complaints. They also suggest that famous people verbal fluency and naming tasks could be useful in detecting cognitive decline at the preclinical stage of AD.

Intertwined depressive and cognitive trajectories and the risk of dementia and death in older adults: a competing risk analysis

Background

Depressive symptoms and cognitive impairment often interact, rendering their associations controversial. To date, their joint trajectories and associations with dementia and death remain underexplored.

Aims

To explore the interactions between depressive symptoms and cognitive function, their developmental trajectories and the associations with all-cause dementia, Alzheimer's disease (AD) and all-cause death in older adults.

Methods

Data were from the Health and Retirement Study. Depressive symptoms and cognitive function were measured using the 8-item Centre for Epidemiologic Studies Depression Scale and the Telephone Interview of Cognitive Status, respectively. All-cause dementia and AD were defined by self-reported or proxy-reported physician diagnoses. All-cause death was determined by interviews. The restricted cubic spline, group-based trajectory modelling and subdistribution hazard regression were used.

Results

Significant interactions between depressive symptoms and cognitive function in 2010 in their association with new-onset all-cause dementia and AD from 2010 to 2020 were found, especially in women (p for interaction <0.05). Independent trajectory analysis showed that emerging or high (vs no) depressive trajectories and poor or rapidly decreased cognitive trajectories (vs very good) from 1996 to 2010 were at significantly higher risk of subsequent all-cause dementia, AD and all-cause death. 15 joint trajectories of depressive symptoms and cognitive function from 1996 to 2010 were determined, where rapidly decreased cognitive function was more common in those with no depressive symptoms. Compared with older adults with the trajectory of no depressive symptoms and very good cognitive function, those with the trajectory of no depressive symptoms but rapidly decreased cognitive function were much more likely to develop new-onset all-cause dementia and death, with subdistribution hazard ratios (95% confidence intervals) of 4.47 (2.99 to 6.67) and 1.84 (1.43 to 2.36), especially in women.

Conclusions

To effectively mitigate the risk of dementia and death, it is crucial to acknowledge the importance of preventing cognitive decline in older adults without depressive symptoms, particularly in women.

Predictors of progression from subjective cognitive decline to objective cognitive impairment: A systematic review and meta-analysis of longitudinal studies

BACKGROUND

Subjective cognitive decline is one of the first symptoms of dementia. With increasing awareness of brain health and a rising prevalence of dementia, a growing number of individuals seek medical assistance for purely subjective cognitive decline. However, only individuals with specific characteristics tend to experience clinical progression.

OBJECTIVES

This study aims to summarize the predictors of objective cognitive impairment in individuals with subjective cognitive decline and to identify those at higher risk of clinical progression.

DESIGN

Systematic review and meta-analysis.

METHODS

We systematically searched 11 electronic databases from inception to February 1, 2023, for longitudinal studies investigating factors associated with the clinical progression of subjective cognitive decline. Effect sizes were pooled using fixed-effects and random-effects models. Leveraging the results of the meta-analysis, we developed two risk prediction models for objective cognitive impairment.

RESULTS

Forty-six cohort studies were included in the systematic review, of which 28 met the meta-analysis criteria. Fifteen predictors were identified, including 4 biomarkers (amyloid β deposition, lower Hulstaert Formula scores, apolipoprotein e4, and hippocampus atrophy), four epidemiological factors (older age at baseline, impaired instrumental activity of daily living, depression, and anxiety), and seven neuropsychological factors (participants in clinical settings, older age at onset, stable symptom, concerns, cognitive decline confirmed by informant, severe symptoms, and poor performance on Trail Making Test B). Based on the meta-analysis results, we developed two risk prediction models. The first model (Model1) incorporates epidemiological and neuropsychological factors, distinguishing individuals with low and medium risk. The second model (Model2) includes additional biomarkers to enhance predictive performance and identify individuals at high risk.

CONCLUSIONS

This study provides a comprehensive characterization of individuals undergoing clinical progression from subjective cognitive decline to mild cognitive impairment or dementia. The developed models support the prediction of progression risk in both memory clinic and community settings, aiding in the early identification of individuals at risk of disease conversion and facilitating the translation of evidence into clinical practice.

REGISTRATION

The systematic review and meta-analysis have been registered in PROSPERO (CRD 42023392476).

TWEETABLE ABSTRACT

Factors for predicting progression from subjective cognitive decline to objective cognitive impairment: evidence from longitudinal studies.

Relationship between serum apolipoprotein B levels and depressive symptoms in elderly Chinese patients with mild cognitive impairment: A large-scale cross-sectional and five-year follow-up study

BACKGROUND

Patients with mild cognitive impairment (MCI) often have depressive symptoms. The purpose of this study was to investigate the effects of depressive symptoms on lipid metabolism and future cognitive function in patients with MCI.

METHODS

A total of 1014 patients with MCI were included. Their demographic data, clinical data, and lipid parameters were collected. Meanwhile, they also completed a series of scale assessments, including Geriatric depression scale (GDS), Ability of Daily Living (ADL), Montreal cognitive assessment (MoCA) and Block Design Test (BDT). Then these patients were also followed for five years.

RESULTS

Patients with depressive symptoms had lower serum apolipoprotein B (ApoB) levels, lower BDT scores and higher ADL scale scores. Correlation analysis showed that GDS was significantly associated with BDT and ADL. Moreover, logistic regression analysis found that ApoB was associated with depressive symptoms. Cox regression analysis showed that only baseline MoCA scores could predict the risk of future MCI transition to dementia.

CONCLUSIONS

Our results suggest low serum ApoB levels may be associated with depressive symptoms in patients with MCI. However, depressive mood or lipids alone may not predict the risk of MCI transition to dementia.

Behavioral marker-based predictive modeling of functional status for older adults with subjective cognitive decline and mild cognitive impairment: Study protocol

Objective

This study describes a research protocol for a behavioral marker-based predictive model that examines the functional status of older adults with subjective cognitive decline and mild cognitive impairment.

Methods

A total of 130 older adults aged ≥65 years with subjective cognitive decline or mild cognitive impairment will be recruited from the Dementia Relief Centers or the Community Service Centers. Data on behavioral and psychosocial markers (e.g. physical activity, mobility, sleep/wake patterns, social interaction, and mild behavioral impairment) will be collected using passive wearable actigraphy, in-person questionnaires, and smartphone-based ecological momentary assessments. Two follow-up assessments will be performed at 12 and 24 months after baseline. Mixed-effect machine learning models: MErf, MEgbm, MEmod, and MEctree, and standard machine learning models without random effects [random forest, gradient boosting machine] will be employed in our analyses to predict functional status over time.

Results

The results of this study will be fundamental for developing tailored digital interventions that apply deep learning techniques to behavioral data to predict, identify, and aid in the management of functional decline in older adults with subjective cognitive decline and mild cognitive impairment. These older adults are considered the optimal target population for preventive interventions and will benefit from such tailored strategies.

Conclusions

Our study will contribute to the development of self-care interventions that utilize behavioral data and machine learning techniques to provide automated analyses of the functional decline of older adults who are at risk for dementia.

A multidimensional model of memory complaints in older individuals and the associated hub regions

Memory complaints are highly prevalent among middle-aged and older adults, and they are frequently reported in individuals experiencing subjective cognitive decline (SCD). SCD has received increasing attention due to its implications for the early detection of dementia. This study aims to advance our comprehension of individuals with SCD by elucidating potential cognitive/psychologic-contributing factors and characterizing cerebral hubs within the brain network. To identify these potential contributing factors, a structural equation modeling approach was employed to investigate the relationships between various factors, such as metacognitive beliefs, personality, anxiety, depression, self-esteem, and resilience, and memory complaints. Our findings revealed that self-esteem and conscientiousness significantly influenced memory complaints. At the cerebral level, analysis of delta and theta electroencephalographic frequency bands recorded during rest was conducted to identify hub regions using a local centrality metric known as betweenness centrality. Notably, our study demonstrated that certain brain regions undergo changes in their hub roles in response to the pathology of SCD. Specifically, the inferior temporal gyrus and the left orbitofrontal area transition into hubs, while the dorsolateral prefrontal cortex and the middle temporal gyrus lose their hub function in the presence of SCD. This rewiring of the neural network may be interpreted as a compensatory response employed by the brain in response to SCD, wherein functional connectivity is maintained or restored by reallocating resources to other regions.

Multi-nutrient interventions and cognitive ageing: are we barking up the right tree?

As we continue to elucidate the mechanisms underlying age-related brain diseases, the reductionist strategy in nutrition–brain function research has focused on establishing the impact of individual foods. However, the biological processes connecting diet and cognition are complex. Therefore, consideration of a combination of nutritional compounds may be most efficacious. One barrier to establishing the efficacy of multi-nutrient interventions is that the area lacks an established set of evidence-based guidelines for studying their effect on brain health. This review is an output of the International Life Sciences Institute (ILSI) Europe. A multi-disciplinary expert group was assembled with the aim of developing a set of considerations to guide research into the effects of multi-nutrient combinations on brain functions. Consensus recommendations converged on six key issues that should be considered to advance research in this area: (1) establish working mechanisms of the combination and contributions of each individual compound; (2) validate the relevance of the mechanisms for the targeted human condition; (3) include current nutrient status, intake or dietary pattern as inclusion/exclusion criteria in the study design; (4) select a participant population that is clinically and biologically appropriate for all nutritional components of the combination; (5) consider a range of cognitive outcomes; (6) consider the limits of reductionism and the ‘gold standard’ randomised controlled trial. These guiding principles will enhance our understanding of the interactive/complementary activities of dietary components, thereby strengthening the evidence base for recommendations aimed at delaying cognitive decline.

Recent contributions to the field of subjective cognitive decline in aging: A literature review

Subjective cognitive decline (SCD) is defined as self-experienced, persistent concerns of decline in cognitive capacity in the context of normal performance on objective cognitive measures. Although SCD was initially thought to represent the "worried well," these concerns can be linked to subtle brain changes prior to changes in objective cognitive performance and, therefore, in some individuals, SCD may represent the early stages of an underlying neurodegenerative disease process (e.g., Alzheimer's disease). The field of SCD research has expanded rapidly over the years, and this review aims to provide an update on new advances in, and contributions to, the field of SCD in key areas and themes identified by researchers in this field as particularly important and impactful. First, we highlight recent studies examining sociodemographic and genetic risk factors for SCD, including explorations of SCD across racial and ethnic minoritized groups, and examinations of sex and gender considerations. Next, we review new findings on relationships between SCD and in vivo markers of pathophysiology, utilizing neuroimaging and biofluid data, as well as associations between SCD and objective cognitive tests and neuropsychiatric measures. Finally, we summarize recent work on interventions for SCD and areas of future growth in the field of SCD.

Education as a Moderator of Help Seeking Behavior in Subjective Cognitive Decline

OBJECTIVE

Disparities in Alzheimer disease (AD) and differences in help seeking (HS) across sociodemographic groups warrant public health concern. Research addressing such disparities must shift toward the earliest clinical manifestations of AD to optimize diagnosis, intervention and care planning. Subjective cognitive decline (SCD), a risk state for AD, provides an important context in which to examine sociodemographic-related disparities in HS.

PARTICIPANTS AND METHODS

One hundred sixty-seven cognitively healthy older adults (M age =73, M education =16) (26.4% Black, Asian, or "Other") completed SCD questionnaire, HS questions, and mood measures (depression and anxiety). Binary logistic adjusted regressions examined: (a) the association between SCD and HS; and (b) the extent to which education moderated the relationship between SCD and HS. SCD [b = 0.06, SE=0.13, P <0.001, odds ratio=1.06, 95% CI (1.03, 1.08)] and education [b=0.32, SE=0.09, P <0.001, odds ratio=1.37, 95% CI (1.15, 1.64)] were independently associated with HS, with significant interaction between education and SCD on HS [b=0.2, SE=0.01, P =0.01, odds ratio=1.02, 95% CI (1.00, 1.03)].

CONCLUSIONS

Findings elucidate the importance of tailoring SCD-related psychoeducational resources depending on educational background as a preliminary stepping-stone in encouraging HS among older adults who may be at particular risk for developing dementia.

Effects of race, baseline cognition, and APOE on the association of affective dysregulation with incident dementia: A longitudinal study of dementia-free older adults

BACKGROUND

Affective symptoms are dementia risk factors. Mild behavioral impairment (MBI) is a neurobehavioral syndrome that refines incorporation of psychiatric symptomatology into dementia prognostication by stipulating symptoms must emerge de novo in later life and persist for ≥6 months. Here, we investigated the longitudinal association of MBI-affective dysregulation with incident dementia.

METHODS

National Alzheimer Coordinating Centre participants with normal cognition (NC) or mild cognitive impairment (MCI) were included. MBI-affective dysregulation was operationalized as Neuropsychiatric Inventory Questionnaire-measured depression, anxiety, and elation at two consecutive visits. Comparators had no neuropsychiatric symptoms (no NPS) in advance of dementia. Cox proportional hazard models were implemented to assess the risk of dementia, adjusted for age, sex, years of education, race, cognitive diagnosis, and APOE-ε4 status, with interaction terms as appropriate.

RESULTS

The final sample included 3698 no-NPS (age:72.8; 62.7 % female), and 1286 MBI-affective dysregulation participants (age:75; 54.5 % female). MBI-affective dysregulation had lower dementia-free survival (p < 0.0001) and greater incidence of dementia (HR = 1.76, CI:1.48-2.08, p < 0.001) versus no NPS. Interaction analyses revealed that MBI-affective dysregulation was associated with higher dementia incidence in Black participants than White (HR = 1.70, CI:1.00-2.87, p = 0.046), NC than MCI (HR = 1.73, CI:1.21-2.48, p = 0.0028), and APOE-ε4 noncarriers than carriers (HR = 1.47, CI:1.06-2.02, p = 0.0195). Of MBI-affective dysregulation converters to dementia, 85.5 % developed Alzheimer's disease, which increased to 91.4 % in those with amnestic MCI.

LIMITATIONS

MBI-affective dysregulation was not stratified by symptom to further examine dementia risk.

CONCLUSIONS

Emergent and persistent affective dysregulation in dementia-free older adults is associated with substantial risk for dementia and should be considered in clinical assessments.

Vision impairment, hearing impairment and functional Limitations of subjective cognitive decline: a population-based study

BACKGROUND

The association between sensory impairment including vision impairment (VI), hearing impairment (HI), dual impairment (DI) and the functional limitations of SCD (SCD-related FL) are still unclear in middle-aged and older people.

METHODS

162,083 participants from BRFSS in 2019 to 2020 was used in this cross-sectional study. After adjusting the weights, multiple logistic regression was used to study the relationship between sensory impairment and SCD or SCD-related FL. In addition, we performed subgroup analysis on the basis of interaction between sensory impairment and covariates.

RESULTS

Participants who reported sensory impairment were more likely to report SCD or SCD-related FL compared to those without sensory impairment (p < 0.001). The association between dual impairment and SCD-related FL was the strongest, the adjusted odds ratios (aORs) and 95% confidence interval (95% CI) were [HI, 2.88 (2.41, 3.43); VI, 3.15(2.61, 3.81); DI, 6.78(5.43, 8.47)] respectively. In addition, subgroup analysis showed that men with sensory impairment were more likely to report SCD-related FL than women, the aORs and 95% CI were [HI, 3.15(2.48, 3.99) vs2.69(2.09, 3.46); VI,3.67(2.79, 4.83) vs. 2.86(2.22, 3.70); DI, 9.07(6.67, 12.35) vs. 5.03(3.72, 6.81)] respectively. The subject of married with dual impairment had a stronger association with SCD-related FL than unmarried subjects the aOR and 95% CI was [9.58(6.69, 13.71) vs. 5.33(4.14, 6.87)].

CONCLUSIONS

Sensory impairment was strongly associated with SCD and SCD-related FL. Individuals with dual impairment had the greatest possibility to reported SCD-related FL, and the association was stronger for men or married subjects than other subjects.

Depression and anxiety in people with cognitive impairment and dementia during the COVID-19 pandemic: Analysis of the English Longitudinal Study of Ageing

BACKGROUND

Some studies have identified declines in mental health during the Coronavirus Disease 2019 (COVID-19) pandemic in different age groups, including older people. As anxiety and depression are common neuropsychiatric symptoms among people with cognitive impairment, the mental health experiences of older people during the pandemic should take cognitive function into consideration, along with assessments made prior to the pandemic. This study addresses evidence gaps to test whether changes in depression and anxiety among older people through the COVID-19 pandemic were associated with cognitive impairment. It also investigates whether associations varied according to key sources of sociodemographic inequality.

METHODS AND FINDINGS

Using data from the English Longitudinal Study of Ageing (ELSA) collected from 2018/2019 to November/December 2020, we estimated changes in depression and anxiety for people aged 50+ in England across 3 cognitive function groups: no impairment, mild cognitive impairment, and dementia. Conditional growth curve models were estimated for continuous measures over 3 time points (N = 5,286), with mixed-effects logistic regression used for binary measures. All models adjusted for demographics (age, gender, ethnicity, and cohabiting partnership), socioeconomics (education, wealth, and employment status), geography (urban/rural and English region), and health (self-rated and the presence of multimorbidity). We found that depression (measured with CES-D score) worsened from 2018/2019 to November/December 2020 for people with mild cognitive impairment (1.39 (95% CI: 1.29 to 1.49) to 2.16 (2.02 to 2.30)) or no impairment (1.17 (95%CI: 1.12 to 1.22) to 2.03 (1.96 to 2.10)). Anxiety, using a single-item rating of 0 to 10 also worsened among those with mild cognitive impairment (2.48 (2.30 to 2.66) to 3.14 (2.95 to 3.33)) or no impairment (2.20 (2.11 to 2.28) to 2.85 (2.77 to 2.95)). No statistically significant increases were found for those with dementia. Using a clinical cutoff for likely depression (CES-D ≥4), we found statistically significant increases in the probability of depression between 2018/2019 and November/December 2020 for those with no impairment (0.110 (0.099 to 0.120) to 0.206 (0.191 to 0.222)) and mild impairment (0.139 (0.120 to 0.159) to 0.234 (0.204 to 0.263)). We also found that differences according to cognitive function that existed before the pandemic were no longer present by June/July 2020, and there were no statistically significant differences in depression or anxiety among cognitive groups in November/December 2020. Wealth and education appeared to be stronger drivers for depression and anxiety, respectively, than cognitive impairment. For example, those with no impairment in the richest two-thirds scored 1.76 (1.69 to 1.82) for depression in June/July, compared to 2.01 (1.91 to 2.12) for those with no impairment in the poorest third and 2.03 (1.87 to 2.19) for those with impairment in the poorest third. Results may be limited by the small number of people with dementia and are generalizable only to people living in the community, not to those in institutional care settings.

CONCLUSIONS

Our findings suggest a convergence in mental health across cognitive function groups during the pandemic. This suggests mental health services will need to meet an increased demand from older adults, especially those not living with cognitive impairment. Further, with little significant change among those with dementia, their existing need for support will remain; policymakers and care practitioners should ensure this group continues to have equitable access to mental health support.

Association between mild cognitive impairment and falls among Chinese older adults: the mediating roles of balance capacity and depressive symptoms

BACKGROUND

This study aimed to examine the association between mild cognitive impairment (MCI) and the follow-up risk of falls among Chinese older adults, exploring the mediating roles of balance capacity and depressive symptoms in the association between MCI and falls.

METHODS

A total of 5482 adults aged 60 years and above from waves 2015 and 2018 of the China Health and Retirement Longitudinal Study were included for analysis. Cognition was assessed by a global cognition score, which included three tests: episodic memory, figure drawing and Telephone Interview of Cognitive Status. Depressive symptoms were assessed with the Centre for Epidemiological Studies Depression Scale. Logistic regression models were used to estimate the association between MCI and falls. Mediation analysis was employed to explore the potential mediating roles of balance capacity and depressive symptoms in the association between MCI and falls.

RESULTS

MCI was significantly associated with the risk of falls (OR 1.259, 95% CI 1.080 to 1.467). Balance capacity and depressive symptoms played parallel mediating roles in the association between MCI and falls, and the mediating effects were 0.004 (95% CI 0.003 to 0.024) and 0.010 (95% CI 0.004 to 0.016), respectively.

CONCLUSIONS

It is necessary to screen for and recognise MCI in order to prevent falls among older adults. More efforts should be made to improve balance capacity and relieve depressive symptoms to reduce the risk of falls among older adults with MCI.

Clinical prediction of magnetic resonance image compilation in patients with mild cognitive impairment

This study aims to investigate the clinical prediction of magnetic resonance image compilation (MAGiC) and magnetic resonance image (MRI) in early diagnosis of the patients with mild cognitive impairment. This study is a retrospective randomized controlled clinical trial, and all patients are divided into following two groups: experiment group and control group. Patients in the experiment group are detected by MAGiC, and patients in the control group are detected by MRI; the clinical material from the two groups of patients with MCI are collected, and then Wechsler Memory Scale-Logical Memory (WMS-LM) and Mini-Mental State Examination (MMSE) are recorded by follow-up. Images by MAGiC have higher accuracy and definition compared with those by MRI. WMS-LM score and MMSE score in the experiment group are significantly better than those in the control group. We can conclude that MAGiC is a promising way to evaluate the clinical prediction in patients with MCI.

How much time of sedentary behavior is associated with depressive symptoms in community-dwelling older adults in southern Brazil?

AIMS

Identify sedentary behavior (SB) cut-off points to screen for depressive symptoms in older adults and verify the association between these conditions.

METHODS

A cross-sectional survey of 308 community-dwelling older adults was conducted. The outcome was the presence of depressive symptoms (≥6 points on the Geriatric Depression Scale-15). The exposure was SB using the self-reported time on a weekday and weekend (International Physical Activity Questionnaire). The cut-off points for SB categorization were determined by the receiver operating characteristic curve and multivariate logistic regression to verify the association.

RESULTS

Older adults who spent ≥4.5 hours/day in SB (sensitivity = 48.8%; specificity = 67.8%) were 1.81 times more likely (95%CI: 1.03;3.15) to have depressive symptoms compared to those who stayed for shorter periods.

CONCLUSIONS

There was an association between SB and depressive symptoms; therefore, older adults must have SB <4.5 hours/day to reduce the chances of developing depressive symptoms.

Screening and Assessment for Alzheimer's Disease in the Days of Biological Biomarkers

The 1980s saw an upsurge of research in Alzheimer's disease (AD). The necessity of standardized assessment batteries became apparent, leading to the development of standardized instruments, such as the CERAD, the CAMDEX, the CSI 'D', and later the TOOLBOX. The advent of new biological markers has led to speculation in the research community about the necessity for these instruments. As the association of biomarkers with subsequent clinical dementia remains unclear, assessment batteries are still necessary, especially with growing evidence that prodromal symptoms of AD may not be cognitive decline but emotional or behavioral symptoms. Inclusion of ethnic minority groups is also essential.

Metacognition in Community-Dwelling Older Black and African American Adults During the COVID-19 Pandemic

BACKGROUND

Cognitive assessment of older adults typically includes symptom reports and objective evaluations. However, there is often poor agreement between these measures. Cultural norms, stress, and anxiety may also influence cognitive self-appraisal and performance. Little research describes how other factors affect the self-report/objective test discrepancies noted in the literature.

OBJECTIVE

This study investigated whether the disparity between subjective cognitive concerns and objective cognitive performance is related to measures of anxiety and stress in older Black and African American adults.

METHODS

Telephone screenings were administered to 206 older adults (ages 64-94) during the first year of the pandemic. Demographic data, objective memory (Telephone Interview for Cognitive Status [TICS-m]), an adaptation of the subjective memory measure, the Cognitive Change Questionnaire, emphasizing executive functioning in everyday life [CCQ-e]), Generalized Anxiety Disorder-7 (GAD-7), and Perceived Stress Scale-4 (PSS4) were measured. Metacognition Discrepancy Index (MDI) was calculated from the standardized residual after regressing TICS-m on CCQ-e scores to quantify the discrepancy between cognitive self-appraisal and objective cognitive functioning.

RESULTS

Neither GAD-7 nor PSS-4 moderated the relationship between TICS-m and CCQ-e, and TICS-m scores weakly predicted subjective CCQ-e scores (F(1, 197)=4.37, p = 0.038, R2 = 0.022). The MDI correlated with stress and anxiety (rs = 0.294, 0.396, ps < 0.001).

CONCLUSION

Discrepancies exist between objectively measured and self-evaluated cognition. Elevations in stress and anxiety are associated with greater overestimation of cognitive difficulties relative to objective performance. Pandemic-related stressors may have worsened anxiety and diminished self-appraisal of cognitive abilities for some individuals, while others may remain reluctant to acknowledge impairments. Social and emotional factors are meaningful considerations in assessing cognitive difficulties.

Effects of a mindfulness-based versus a health self-management intervention on objective cognitive performance in older adults with subjective cognitive decline (SCD): a secondary analysis of the SCD-Well randomized controlled trial

Background

Older individuals with subjective cognitive decline (SCD) perceive that their cognition has declined but do not show objective impairment on neuropsychological tests. Individuals with SCD are at elevated risk of objective cognitive decline and incident dementia. Non-pharmacological interventions (including mindfulness-based and health self-management approaches) are a potential strategy to maintain or improve cognition in SCD, which may ultimately reduce dementia risk.

Methods

This study utilized data from the SCD-Well randomized controlled trial. One hundred forty-seven older adults with SCD (MAge = 72.7 years; 64% female) were recruited from memory clinics in four European countries and randomized to one of two group-based, 8-week interventions: a Caring Mindfulness-based Approach for Seniors (CMBAS) or a health self-management program (HSMP). Participants were assessed at baseline, post-intervention (week 8), and at 6-month follow-up (week 24) using a range of cognitive tests. From these tests, three composites were derived—an “abridged” Preclinical Alzheimer’s Cognitive Composite 5 (PACC5Abridged), an attention composite, and an executive function composite. Both per-protocol and intention-to-treat analyses were performed. Linear mixed models evaluated the change in outcomes between and within arms and adjusted for covariates and cognitive retest effects. Sensitivity models repeated the per-protocol analyses for participants who attended ≥ 4 intervention sessions.

Results

Across all cognitive composites, there were no significant time-by-trial arm interactions and no measurable cognitive retest effects; sensitivity analyses supported these results. Improvements, however, were observed within both trial arms on the PACC5Abridged from baseline to follow-up (Δ [95% confidence interval]: CMBAS = 0.34 [0.19, 0.48]; HSMP = 0.30 [0.15, 0.44]). There was weaker evidence of an improvement in attention but no effects on executive function.

Conclusions

Two non-pharmacological interventions conferred small, non-differing improvements to a global cognitive composite sensitive to amyloid-beta-related decline. There was weaker evidence of an effect on attention, and no evidence of an effect on executive function. Importantly, observed improvements were maintained beyond the end of the interventions. Improving cognition is an important step toward dementia prevention, and future research is needed to delineate the mechanisms of action of these interventions and to utilize clinical endpoints (i.e., progression to mild cognitive impairment or dementia).

Trial registration

ClinicalTrials.gov, NCT03005652.

Subjective cognitive decline and anxious/depressive symptoms during the COVID-19 pandemic: what is the role of stress perception, stress resilience, and β-amyloid?

BACKGROUND

The COVID-19 pandemic may worsen the mental health of people reporting subjective cognitive decline (SCD) and therefore their clinical prognosis. We aimed to investigate the association between the intensity of SCD and anxious/depressive symptoms during confinement and the underlying mechanisms.

METHODS

Two hundred fifty cognitively unimpaired participants completed the Hospital Anxiety and Depression Scale (HADS) and SCD-Questionnaire (SCD-Q) and underwent amyloid-β positron emission tomography imaging with [18F] flutemetamol (N = 205) on average 2.4 (± 0.8) years before the COVID-19 confinement. During the confinement, participants completed the HADS, Perceived Stress Scale (PSS), Brief Resilience Scale (BRS), and an ad hoc questionnaire on worries (access to primary products, self-protection materials, economic situation) and lifestyle changes (sleep duration, sleep quality, eating habits). We investigated stress-related measurements, worries, and lifestyle changes in relation to SCD. We then conducted an analysis of covariance to investigate the association of SCD-Q with HADS scores during the confinement while controlling for pre-confinement anxiety/depression scores and demographics. Furthermore, we introduced amyloid-β positivity, PSS, and BRS in the models and performed mediation analyses to explore the mechanisms explaining the association between SCD and anxiety/depression.

RESULTS

In the whole sample, the average SCD-Q score was 4.1 (± 4.4); 70 (28%) participants were classified as SCD, and 26 (12.7%) were amyloid-β-positive. During the confinement, participants reporting SCD showed higher PSS (p = 0.035) but not BRS scores (p = 0.65) than those that did not report SCD. No differences in worries or lifestyle changes were observed. Higher SCD-Q scores showed an association with greater anxiety/depression scores irrespective of pre-confinement anxiety/depression levels (p = 0.002). This association was not significant after introducing amyloid-β positivity and stress-related variables in the model (p = 0.069). Amyloid-β positivity and PSS were associated with greater HADS irrespective of pre-confinement anxiety/depression scores (p = 0.023; p < 0.001). The association of SCD-Q with HADS was mediated by PSS (p = 0.01).

CONCLUSIONS

Higher intensity of SCD, amyloid-β positivity, and stress perception showed independent associations with anxious/depressive symptoms during the COVID-19 confinement irrespective of pre-confinement anxiety/depression levels. The association of SCD intensity with anxiety/depression was mediated by stress perception, suggesting stress regulation as a potential intervention to reduce affective symptomatology in the SCD population in the face of stressors.

Static and dynamic functional connectivity variability of the anterior-posterior hippocampus with subjective cognitive decline

Background

Subjective cognitive decline (SCD) is a putative Alzheimer’s disease (AD) precursor without objective neuropsychological deficits. The hippocampus plays an important role in cognitive function and emotional responses and is generally aberrant in SCD. However, previous studies have mainly focused on static functional connectivity (sFC) by resting-state functional magnetic resonance imaging (fMRI) in SCD individuals, and it remains unclear whether hippocampal dynamic functional connectivity (dFC) changes exist in SCD and whether those changes are associated with subtle changes in cognitive function or affect.

Methods

Seventy SCD patients and 65 healthy controls were recruited. Demographic data, comprehensive neuropsychology assessments, and resting-state fMRI data were collected. The bilateral anterior and posterior hippocampi were selected as seeds to investigate the static and dynamic functional connectivity alterations in SCD.

Results

Compared to healthy controls, subjects with SCD exhibited: (1) decreased sFC between the left caudal hippocampus and left precuneus; (2) decreased dFC variability between the bilateral caudal hippocampus and precuneus; (3) increased dFC variability between the bilateral rostral hippocampus and caudate nucleus; and (4) increased dFC variability between the left rostral hippocampus and left olfactory cortex. Additionally, the attention scores were positively correlated with dFC variability between the left posterior hippocampus and left precuneus, and the dFC variability between the bilateral anterior hippocampus and caudate nucleus was positively correlated with depression scores and negatively correlated with global cognition scores.

Conclusion

SCD individuals exhibited abnormal sFC and dFC in the anterior-posterior hippocampus, and abnormal dFC was more widespread than abnormal sFC. A combination of sFC and dFC provides a new perspective for exploring the brain pathophysiological mechanisms in SCD and offers potential neuroimaging biomarkers for the early diagnosis and intervention of AD.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13195-022-01066-9.

Progression from Subjective Cognitive Decline to Mild Cognitive Impairment or Dementia: The Role of Baseline Cognitive Performance

Background: Older adults with subjective cognitive decline (SCD) are at an increased risk of progression to mild cognitive impairment (MCI) or dementia. However, few have examined the specific cognitive tests that are associated with progression. Objective: This study examined performance on 18 neuropsychological tests among participants with SCD who later progressed to MCI or dementia. Methods: We included 131 participants from the Czech Brain Aging Study that had SCD at baseline. They completed a comprehensive neuropsychological battery including cognitive tests from the Uniform Data Set 2.0 enriched by the verbal memory test Rey Auditory Verbal Learning Test (RAVLT) and Rey-Osterrieth Complex Figure Test (ROCFT). Results: Fifty-five participants progressed: 53% to non-amnestic MCI (naMCI), 44% to amnestic MCI (aMCI), and 4% to dementia. Scoring one SD below the mean at baseline on the RAVLT 1 and RAVLT 1–5 was associated with 133% (RAVLT 1; HR: 2.33 [1.50, 3.62]) and 122% (RAVLT 1–5; HR: 2.22 [1.55, 3.16]) greater risk of progression to MCI or dementia over 3.84 years on average. Worse performance on the RAVLT 5, RAVLT 1–5, RAVLT 30, and ROCFT–Recall was associated with progression to aMCI whereas worse performance on the RAVLT 1, TMT B, and Boston Naming Test was associated with progression to naMCI. Conclusion: At baseline, lower verbal memory performance was most strongly associated with progression to aMCI whereas lower executive or language performance was most strongly associated with progression to naMCI.