The dual role of cognitive reserve in subjective cognitive decline and mild cognitive impairment: a 7-year follow-up study

Interaction between catechol-O-methyltransferase Val/Met polymorphism and cognitive reserve for negative symptoms in schizophrenia

BACKGROUND

Cognitive reserve (CR) and the catechol-O-methyltransferase (COMT) Val/Met polymorphism are reportedly linked to negative symptoms in schizophrenia. However, the regulatory effect of the COMT genotype on the relationship between CR and negative symptoms is still unexamined.

AIM

To investigate whether the relationship between CR and negative symptoms could be regulated by the COMT Val/Met polymorphism.

METHODS

In a cross-sectional study, 54 clinically stable patients with schizophrenia underwent assessments for the COMT genotype, CR, and negative symptoms. CR was estimated using scores in the information and similarities subtests of a short form of the Chinese version of the Wechsler Adult Intelligence Scale.

RESULTS

COMT Met-carriers exhibited fewer negative symptoms than Val homozygotes. In the total sample, significant negative correlations were found between negative symptoms and information, similarities. Associations between information, similarities and negative symptoms were observed in Val homozygotes only, with information and similarities showing interaction effects with the COMT genotype in relation to negative symptoms (information, β = -0.282, 95%CI: -0.552 to -0.011, P = 0.042; similarities, β = -0.250, 95%CI: -0.495 to -0.004, P = 0.046).

CONCLUSION

This study provides initial evidence that the association between negative symptoms and CR is under the regulation of the COMT genotype in schizophrenia.

Association Between Years of Education and Amyloid Burden in Patients With Subjective Cognitive Decline, MCI, and Alzheimer Disease

OBJECTIVES

Higher-educated patients with Alzheimer disease (AD) can harbor greater neuropathologic burden than those with less education despite similar symptom severity. In this study, we assessed whether this observation is also present in potential preclinical AD stages, namely in individuals with subjective cognitive decline and clinical features increasing AD likelihood (SCD+).

METHODS

Amyloid-PET information ([18F]Flutemetamol or [18F]Florbetaben) of individuals with SCD+, mild cognitive impairment (MCI), and AD were retrieved from the AMYPAD-DPMS cohort, a multicenter randomized controlled study. Group classification was based on the recommendations by the SCD-I and NIA-AA working groups. Amyloid PET images were acquired within 8 months after initial screening and processed with AMYPYPE. Amyloid load was based on global Centiloid (CL) values. Educational level was indexed by formal schooling and subsequent higher education in years. Using linear regression analysis, the main effect of education on CL values was tested across the entire cohort, followed by the assessment of an education-by-diagnostic-group interaction (covariates: age, sex, and recruiting memory clinic). To account for influences of non-AD pathology and comorbidities concerning the tested amyloid-education association, we compared white matter hyperintensity (WMH) severity, cardiovascular events, depression, and anxiety history between lower-educated and higher-educated groups within each diagnostic category using the Fisher exact test or χ2 test. Education groups were defined using a median split on education (Md = 13 years) in a subsample of the initial cohort, for whom this information was available.

RESULTS

Across the cohort of 212 individuals with SCD+ (M(Age) = 69.17 years, F 42.45%), 258 individuals with MCI (M(Age) = 72.93, F 43.80%), and 195 individuals with dementia (M(Age) = 74.07, F 48.72%), no main effect of education (ß = 0.52, 95% CI -0.30 to 1.58), but a significant education-by-group interaction on CL values, was found (p = 0.024) using linear regression modeling. This interaction was driven by a negative association of education and CL values in the SCD+ group (ß = -0.11, 95% CI -4.85 to -0.21) and a positive association in the MCI group (ß = 0.15, 95% CI 0.79-5.22). No education-dependent differences in terms of WMH severity and comorbidities were found in the subsample (100 cases with SCD+, 97 cases with MCI, 72 cases with dementia).

DISCUSSION

Education may represent a factor oppositely modulating subjective awareness in preclinical stages and objective severity of ongoing neuropathologic processes in clinical stages.

Cognitive complaints in older adults: relationships between self and informant report, objective test performance, and symptoms of depression

This study explored the relationships between objective measures of cognitive functioning, self and informant reports of cognitive problems in daily life, and depression screening in older adults who had been referred because of reported or suspected cognitive changes. We used archival data from 100, predominantly White (97%), typically educated (M = 13.25 years), older adults (M = 70.38 years) who received an outpatient neuropsychological evaluation. We characterized the cognitive performance using the CVLT-II Total score. We characterized patient and collateral reports using the BRIEF-A MI index, a normed scale of cognitive problems in daily life. We also incorporated a depression screener (PHQ-9) into our analyses. Multiple linear regression analysis revealed that only the informant reported problems in daily life, using the BRIEF-A MI index, was a significant predictor of objective cognitive deficits, as defined by CVLT-II Total scores. Self BRIEF-A MI index scores were not significant predictors of CVLT-II Total performance after we accounted for depression using the patient's PHQ-9 score. Additionally, elevated depression widened the discrepancy between raters, with elevated depression associated with worsening sself-report scores compared to informant-reported scores. As informant-reported problems were the strongest predictor of cognitive deficits, we recommend routine collection of collateral informant reports in the neuropsychological evaluation of older adults referred for cognitive concerns. We also recommend incorporating self-ratings of daily life functioning and screening for depression to contextualize patient complaints and address their concerns, even in the absence of objective cognitive dysfunction.

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

BACKGROUND

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Predicting cognitive dysfunction and regional hubs using Braak staging amyloid-beta biomarkers and machine learning

Mild cognitive impairment (MCI) is a transitional stage between normal aging and early Alzheimer's disease (AD). The presence of extracellular amyloid-beta (Aβ) in Braak regions suggests a connection with cognitive dysfunction in MCI/AD. Investigating the multivariate predictive relationships between regional Aβ biomarkers and cognitive function can aid in the early detection and prevention of AD. We introduced machine learning approaches to estimate cognitive dysfunction from regional Aβ biomarkers and identify the Aβ-related dominant brain regions involved with cognitive impairment. We employed Aβ biomarkers and cognitive measurements from the same individuals to train support vector regression (SVR) and artificial neural network (ANN) models and predict cognitive performance solely based on Aβ biomarkers on the test set. To identify Aβ-related dominant brain regions involved in cognitive prediction, we built the local interpretable model-agnostic explanations (LIME) model. We found elevated Aβ in MCI compared to controls and a stronger correlation between Aβ and cognition, particularly in Braak stages III-IV and V-VII (p < 0.05) biomarkers. Both SVR and ANN, especially ANN, showed strong predictive relationships between regional Aβ biomarkers and cognitive impairment (p < 0.05). LIME integrated with ANN showed that the parahippocampal gyrus, inferior temporal gyrus, and hippocampus were the most decisive Braak regions for predicting cognitive decline. Consistent with previous findings, this new approach suggests relationships between Aβ biomarkers and cognitive impairment. The proposed analytical framework can estimate cognitive impairment from Braak staging Aβ biomarkers and delineate the dominant brain regions collectively involved in AD pathophysiology.

Examining the role of participant and study partner report in widely-used classification approaches of mild cognitive impairment in demographically-diverse community dwelling individuals: results from the Einstein aging study

Objective

The role of subjective cognitive concerns (SCC) as a diagnostic criterion for MCI remains uncertain and limits the development of a universally (or widely)-accepted MCI definition. The optimal MCI definition should define an at-risk state and accurately predict the development of incident dementia. Questions remain about operationalization of definitions of self- and informant-reported SCCs and their individual and joint associations with incident dementia.

Methods

The present study included Einstein Aging Study participants who were non-Hispanic White or Black, free of dementia at enrollment, had follow-up, and completed neuropsychological tests and self-reported SCC at enrollment to determine MCI status. Informant-reported SCC at baseline were assessed via the CERAD clinical history questionnaire. Self-reported SCC were measured using the CERAD, items from the EAS Health Self-Assessment, and the single memory item from the Geriatric Depression Scale. Cox proportional hazards models examined the association of different operationalizations of SCC with Petersen and Jak/Bondi MCI definitions on the risk of dementia, further controlling for age, sex, education, and race/ethnicity. Time-dependent sensitivity and specificity at specific time points for each definition, and Youden's index were calculated as an accuracy measure. Cox proportional hazards models were also used to evaluate the associations of combinations of self- and informant-reported SCC with the risk of incident dementia.

Results

91% of the sample endorsed at least one SCC. Youden's index showed that not including SCC in either Jak/Bondi or Petersen classifications had the best balance between sensitivity and specificity across follow-up. A subset of individuals with informants, on average, had a lower proportion of non-Hispanic Blacks and 94% endorsed at least one self-reported SCC. Both informant-reported and self-reported SCC were significantly associated with incident dementia.

Conclusion

Our findings suggest that the SCC criterion may not improve the predictive validity for dementia when included in widely-employed definitions of MCI. Consistent with some prior research, informant-reported SCC was more related to risk of incident dementia than self-reported SCC. Given that requiring informant report as a diagnostic criterion may unintentionally exclude health disparate groups, additional consideration is needed to determine how best to utilize informant-report in MCI diagnosis.

Openness and age influence cognitive progression: a longitudinal study

BACKGROUND

Some psychological and personality characteristics of individuals seem to determine behavioral patterns that are associated with better health throughout life and, consequently, prevent the progression of early cognitive changes to dementia.

OBJECTIVE

To identify which individuals have modified cognitive ratings after 24 months of follow-up and correlating with personality traits.

METHODS

One hundred and two volunteers were evaluated clinically and for personality characteristics and neuropsychological testing. Of these, 25 subjects were classified as cognitively normal (CN), 25 as subjective cognitive decline (SCD), 28 as nonamnestic mild cognitive impairment (naMCI), and 24 as amnestic mild cognitive impairment (amMCI) at baseline. Follow-up occurred over 2 years from the initial assessment, and the cognitive categories of the participants were re-analyzed every 6 months to observe differences in their classification.

RESULTS

Out of the 102 subjects, 65 remained at follow-up. The sample followed-up longitudinally was composed predominantly of women (65%), white (74%), with a mean age of 78 (±7.5) years old and 12 (±4.8) years of schooling. Throughout the process, 23% of CN, 15% of SDC, and 27% of naMCI individuals worsened cognitively. Amnestic with mild cognitive impairment volunteers remained stable or improved. Individuals with older age show more significant cognitive deterioration, and those with very low or high rates of the openness personality trait are associated with cognitive decline utilizing the Fisher exact test, probably because the open extremes influence choices, stress management, and behavioral maintenance.

CONCLUSION

The factors most associated with cognitive change in this group of older adults were age and the intensity of the openness aspects of personality.

Dimensions of cognitive reserve and their predictive power of cognitive performance and decline in the elderly

Background

The relative importance of different components of cognitive reserve (CR), as well as their differences by gender, are poorly established.

Objective

To explore several dimensions of CR, their differences by gender, and their effects on cognitive performance and trajectory in a cohort of older people without relevant psychiatric, neurologic, or systemic conditions.

Methods

Twenty-one variables related to the education, occupation, social activities, and life habits of 1,093 home-dwelling and cognitively healthy individuals, between 68 and 86 years old, were explored using factorial analyses to delineate several dimensions of CR. These dimensions were contrasted with baseline cognitive performance, follow-up over 5 years of participants' cognitive trajectory, conversion to mild cognitive impairment (MCI), and brain volumes using regression and growth curve models, controlling for gender, age, marital status, number of medications, trait anxiety, depression, and ApoE genotype.

Results

Five highly intercorrelated dimensions of CR were identified, with some differences in their structure and effects based on gender. Three of them, education/occupation, midlife cognitive activities, and leisure activities, were significantly associated with late-life cognitive performance, accounting for more than 20% of its variance. The education/occupation had positive effect on the rate of cognitive decline during the 5-year follow up in individuals with final diagnosis of MCI but showed a reduced risk for MCI in men. None of these dimensions showed significant relationships with gray or white matter volumes.

Conclusion

Proxy markers of CR can be represented by five interrelated dimensions. Education/occupation, midlife cognitive activities, and leisure activities are associated with better cognitive performance in old age and provide a buffer against cognitive impairment. Education/occupation may delay the clinical onset of MCI and is also associated with the rate of change in cognitive performance.

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

BACKGROUND

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

METHODS

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

DISCUSSION

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

TRIAL REGISTRATION NUMBER (TRN)

NCT05569083.

Association between sedentary behavior and risk of cognitive decline or mild cognitive impairment among the elderly: a systematic review and meta-analysis

Background

Existing evidence on the association between sedentary behavior (SB) and cognitive function remains inconclusive. Therefore, this study investigated the association between SB and the risk of cognitive decline (CD) or mild cognitive impairment (MCI) in the elderly.

Methods

A comprehensive search was independently conducted by two researchers (XC and GQ) in seven electronic databases, including Medline (via PubMed), China Biology Medicine, Embase, Web of Science, China National Knowledge Infrastructure, Wanfang database, and VIP database for Chinese technical periodicals, covering studies published from the inception of database to June 2023. Studies that investigated the relationship between SB and the risk of CD or MCI in the elderly were included. The quality of the literature was assessed using the Newcastle-Ottawa Scale (NOS) and the Agency for Healthcare Research and Quality (AHRQ) assessment tools. The combined effect size analysis, subgroup analysis, and publication bias assessment were performed using STATA 14.0.

Results

A total of 13 cross-sectional and 6 cohort studies involving 81,791 individuals were included, comprising 17 high-quality studies and 2 medium-quality studies. We found that SB was significantly associated with an increased risk of CD [odds ratio (OR) = 1.69, 95% confidence intervals (CI): 1.47-1.94] or MCI (OR = 1.34, 95% CI: 1.14-1.56) among the elderly. Subgroup analysis stratified according to comorbidity, lifestyle, family structure, publication year, and region showed statistical differences between groups, and the consistency of the results revealed the sources of the heterogeneity.

Conclusion

This meta-analysis showed that SB is positively associated with the risk of CD or MCI in the elderly, providing a higher level of evidence for the promotion of healthy behaviors by clinicians and health policymakers. Due to the number and quality of the included articles, more high-quality longitudinal studies are needed to further confirm our findings.

The neurocognitive disorder cohort RIFADE: Aims, methods, first results showing cognitive improvement in a subgroup

BACKGROUND

The NCD cohort study RIFADE (RIsk FActors of DEmentia) investigates the interaction of risk factors and neurocognitive disorders (NCDs) due to Alzheimer's disease (NCD-AD) and NCD of vascular type (NCD-vascular). Retrospective recruitment referred to a period from 2007 to 2018 in a single centre. In addition to the baseline visit, follow-up visits took place at 3, 6, 12 months followed by yearly visits. Visit times varied in part depending on adherence. The study also comprises an EEG bank and a bank with cerebral MRI (c-MRI).

METHODS

Inclusion criteria were broad in order to cover a wide range of patterns of NCD. At baseline, patients underwent a large panel of assessments, e.g. including clinical history, diagnostic evaluation for NCD according to DSM-IV and NINDS AIREN criteria, a cognitive test battery including the DemTect, the clock drawing test and the Instrumental-Activities-of-Daily-Living-scale of Lawton and Brodie, EEG and c-MRI. At each follow-up visit, cognitive tests were repeated, in most cases also EEGs and in some cases c-MRIs. Numerous risk factors (RF) including vascular RF, atrial fibrillation, heart failure, sleep apnoea and lifestyle factors such as sedentary lifestyle, low cognitive style and smoking were evaluated for presence and for correction status at each visit, and modulation of uncorrected RF was initiated.

RESULTS

Overall, 126 subjects with a clinical diagnosis of NCD were included (52% female, mean age 71 ± 10.6 years (range 35e86)), number of follow-up visits per subject 2.9 ± 2.4, observation time per subject 3.4 ± 2.8 years). Of these, 55/28/17% presented with the clinical stages subjective cognitive decline (SCD)/mild cognitive impairment (MCI)/dementia (major NCD). Clinical diagnoses, retrospectively re-evaluated according to DSM-5, were 5/21/68/6% Alzheimer´s disease (NCD-AD)/vascular NCD (NCD-vascular) / mixed NCD (NCD-AD + NCD-vascular)/unspecified NCD. First longitudinal results revealed a mean DemTect score at baseline 12.6 ± 4.2 vs last visit 12.0 ± 4.8 (p = 0.08) and a clock drawing test score at baseline 1.9 ± 1.3 vs last visit 2.3 ± 1.5 (p < 0.0001). Of all subjects with MCI or major NCD (n = 57), 19 improved in the clinical stage from baseline to last visit (33.3%). Sixteen subjects progressed from SCD or MCI (n = 104) to major NCD (15.4%).

CONCLUSION

The German NCD cohort RIFADE comprises patients with all clinical stages of NCD. A considerable subgroup improved in clinical stage. Further analysis is needed to answer the question of whether modulation of multiple risk factors provides a favourable effect on cognitive outcome in NCD.

Degradation of EEG microstates patterns in subjective cognitive decline and mild cognitive impairment: Early biomarkers along the Alzheimer's Disease continuum?

Alzheimer's disease (AD) pathological changes may begin up to decades earlier than the appearance of the first symptoms of cognitive decline. Subjective cognitive decline (SCD) could be the first pre-clinical sign of possible AD, which might be followed by mild cognitive impairment (MCI), the initial stage of clinical cognitive decline. However, the neural correlates of these prodromic stages are not completely clear yet. Recent studies suggest that EEG analysis tools characterizing the cortical activity as a whole, such as microstates and cortical regions connectivity, might support a characterization of SCD and MCI conditions. Here we test this approach by performing a broad set of analyses to identify the prominent EEG markers differentiating SCD (n = 57), MCI (n = 46) and healthy control subjects (HC, n = 19). We found that the salient differences were in the temporal structure of the microstates patterns, with MCI being associated with less complex sequences due to the altered transition probability, frequency and duration of canonic microstate C. Spectral content of EEG, network connectivity, and spatial arrangement of microstates were instead largely similar in the three groups. Interestingly, comparing properties of EEG microstates in different cerebrospinal fluid (CSF) biomarkers profiles, we found that canonic microstate C displayed significant differences in topography in AD-like profile. These results show that the progression of dementia might be associated with a degradation of the cortical organization captured by microstates analysis, and that this leads to altered transitions between cortical states. Overall, our approach paves the way for the use of non-invasive EEG recordings in the identification of possible biomarkers of progression to AD from its prodromal states.

18F-AV45 PET and MRI Reveal the Influencing Factors of Alzheimer's Disease Biomarkers in Subjective Cognitive Decline Population

BACKGROUND

Subjective cognitive decline (SCD) is a self-perceived decline in cognitive ability, which exhibits no objective impairment but increased risk of conversion to mild cognitive impairment and Alzheimer's disease (AD).

OBJECTIVE

To investigate how influencing factors (risk gene, age, sex, and education) affect amyloid-β (Aβ) deposition and gray matter (GM) atrophy in SCD population.

METHODS

281 SCD subjects were included in this study, who underwent clinical evaluation, cognitive ability assessment, apolipoprotein E (APOE) genotyping, 18F-Florbetapir positron emission computed tomography, and magnetic resonance imaging screening. Two-sample t tests and analysis of variance were performed based on voxel-wise outcome.

RESULTS

In 281 SCD subjects with an average age of 63.86, 194 subjects (69.04%) were female, and 56 subjects carried APOE ɛ4 genes. Statistical results revealed APOE ɛ4 gene, age, and sex influenced Aβ deposition in different brain regions; moreover, only the interaction exhibited between age and APOE ɛ4 genes. The GM atrophy of hippocampal, amygdala, precentral, and occipital lobes occurred in the group age over 60. The GM volume of the hippocampal, frontal, and occipital lobe in females was less than males. Education has an effect only on cognitive function.

CONCLUSION

In SCD, APOE ɛ4 gene, age, and sex significantly influenced Aβ deposition and APOE ɛ4 gene can interact with age in impacting Aβ deposition. Both age and sex can affect GM atrophy. The results suggested that female SCD with APOE ɛ4 genes and aged more than 60 years old might exhibit advanced AD biomarkers.

Lifelong experiences as a proxy of cognitive reserve moderate the association between connectivity and cognition in Alzheimer's disease

Alzheimer's disease (AD) is associated with alterations in functional connectivity (FC) of the brain. The FC underpinnings of CR, that is, lifelong experiences, are largely unknown. Resting-state FC and structural MRI were performed in 76 CSF amyloid-β (Aβ) negative healthy controls and 152 Aβ positive individuals as an AD spectrum cohort (ADS; 55 with subjective cognitive decline, SCD; 52 with mild cognitive impairment; 45 with AD dementia). Following a region-of-interest (ROI) FC analysis, intrinsic network connectivity within the default-mode network (INC-DMN) and anti-correlation in INC between the DMN and dorsal attention network (DMN:DAN) were obtained as composite scores. CR was estimated by education and Lifetime Experiences Questionnaire (LEQ). The association between INC-DMN and MEM was attenuated by higher LEQ scores in the entire ADS group, particularly in SCD. In ROI analyses, higher LEQ scores were associated with higher FC within the DMN in ADS group. INC-DMN remains relatively intact despite memory decline in individuals with higher lifetime activity estimates, supporting a role for functional networks in maintaining cognitive function in AD.

Cognitive recovery in patients with post-stroke subjective cognitive complaints

Background and purpose

The objective cognitive trajectory in patients with post-stroke subjective cognitive complaints (SCC) over time remained unknown. We investigated cognitive outcomes in patients with SCC within 1 year after stroke, and determined factors associated with cognitive recovery.

Methods

This study included 599 patients with a clinical diagnosis of post-stroke SCC and evidence of cognitive deficits including Clinical Dementia Rating Scale (CDR) = 0.5, Montreal Cognitive Assessment (MoCA) score <26, and Mini–Mental State Examination score >17 (illiterate) or >20 (primary school) or >24 (junior school or above). Neuropsychological assessment was performed at baseline (2 weeks to 6 months after stroke) and 6-month follow-up visit. Cognitive recovery was operationalized as unimpaired cognition (MoCA score ≥26 and CDR = 0) after 6 months. Factors associated with recovery were defined through logistic regression analysis.

Results

After 6 months, 583 patients completed the follow-up with 80 (13.72%) presenting cognitive recovery, among which, 22 (9.48%) cases reported SCC within 2 weeks after stroke, six (10%) at 15–30 days, 13 (15.12%) at 31–60 days, 10 (16.13%) at 61–90 days, five (10.42%) at 91–120 days, nine (23.08%) at 121–150 days, and 15 (26.79%) at 151–180 days. Compared to those reported cognitive complaints at 151–180 days after stroke, patients with early post-stroke SCC had poorer cognitive recovery, which was only significant in individuals with high level of education. Male sex, higher baseline MoCA scores, coffee intake and thalamus lesions were independently associated with high chance of cognitive recovery.

Conclusions

Although post-stroke SCC contributes to persisting objective cognitive deficits, some patients presented cognitive recovery within 1 year after stroke. Patients with a high education level reporting SCC at earlier stage after stroke had poorer cognitive recovery. Male, higher baseline MoCA scores, coffee intake and thalamus lesions appear to independently predict cognitive recovery.

Diurnal dynamic range as index of dysregulation of system dynamics. A cortisol examplar using data from the Study of Midlife in the United States

We discuss the importance of including measures of dysregulated system dynamics in the operationalization of allostatic load. The concept of allostatic load, as originally proposed by McEwen and Stellar, included dysregulation not only in the resting state of physiological systems, but also in system dynamics. We describe previous work on cortisol diurnal dynamic range (peak to nadir spread) as an index of the health of the hypothalamic-pituitary-adrenal axis, with compression of dynamic range being a marker of dysregulation. In particular, we review the evidence for a) diurnal dynamic range compression in people from disadvantaged backgrounds, b) cross-sectional association of cortisol diurnal dynamic range compression with dysregulation in other systems' resting states, and c) cross-sectional association of cortisol diurnal dynamic range compression with lower scores on cognitive testing. Then, we present new data from the Study of Midlife in the United States (MIDUS) on longitudinal associations of cortisol dynamic range compression with subsequent cognitive decline and all-cause mortality. Briefly, each standard deviation decrement in cortisol diurnal dynamic range is associated with adjusted mortality hazard ratio of 1.35 (95% confidence interval: 1.19, 1.54). Among those who scored at median or lower in executive functioning at baseline and survive, each standard deviation decrement in cortisol dynamic range is associated with 1% greater decline in executive functioning over a decade (95% confidence interval: 0.4%, 2.0%). We conclude that including measures of system dynamics like diurnal dynamic range in the next generation of allostatic load measurement will likely advance understanding of the cumulative physiological burden of chronic stress and life experiences, and improve the prediction of future health consequences.

Percentage amplitude of fluctuation and structural covariance changes of subjective cognitive decline in patients: A multimodal imaging study

Back ground

Subjective cognitive decline (SCD) may be the first clinical sign of Alzheimer’s disease (AD). The possible neural mechanisms of SCD are not well known. This study aimed to compare percent amplitude of fluctuation (PerAF) and structural covariance patterns in patients with SCD and healthy controls (HCs).

Methods

We enrolled 53 patients with SCD and 65 HCs. Resting-state functional magnetic resonance imaging (MRI) data and T1-weighted anatomical brain 3.0-T MRI scans were collected. The PerAF approach was applied to distinguish altered brain functions between the two groups. A whole-brain voxel-based morphometry analysis was performed, and all significant regions were selected as regions of interest (ROIs) for the structural covariance analysis. Statistical analysis was performed using two-sample t-tests, and multiple regressions were applied to examine the relationships between neuroimaging findings and clinical symptoms.

Results

Functional MRI results revealed significantly increased PerAF including the right hippocampus (HIPP) and right thalamus (THA) in patients with SCD relative to HCs. Gray matter volume (GMV) results demonstrated decreased GMV in the bilateral ventrolateral prefrontal cortex (vlPFC) and right insula in patients with SCD relative to HCs. Taking these three areas including the bilateral vlPFC and right insula as ROIs, differences were observed in the structural covariance of the ROIs with several regions between the two groups. Additionally, significant correlations were observed between neuroimaging findings and clinical symptoms.

Conclusion

Our study investigated the abnormal PerAF and structural covariance patterns in patients with SCD, which might provide new insights into the pathological mechanisms of SCD.

Effectiveness of Personalized Cognitive Stimulation in Older Adults with Mild Possible Cognitive Impairment: A 12-month Follow-up Cognitive Stimulation in Mild Cognitive Impairment

OBJECTIVE

The objective of this study was to analyze the long-term effects of a personalized cognitive stimulation (PCS) program on the global cognition, cognitive aspects, activities of daily living (ADLs), anxiety, and depression in older adults with possible mild cognitive impairment (MCI).

METHODS

A 12-month follow-up analysis was carried out in a single-blind, randomized clinical trial to research the long-term effects of a 10-week PCS program evaluating the cognitive level, depression, and anxiety of older adults with possible MCI.

RESULTS

Fifty older adults were assessed 12 months after the CS program, 23 in the intervention group and 27 in the control group. There were significant differences between the groups at 12 months in the global cognition (p = .002), in global orientation (p < .001), and in spatial orientation (p = .004) in favor of the intervention group, measured with the Spanish version of the Mini-Mental Status Examination (MEC-35).

CONCLUSIONS

A PCS program could be effective in improving global cognition and global and spatial orientation.

CLINICAL IMPLICATIONS

A PCS program based on cognitive levels in older adults with possible MCI achieves improvements in global cognition and global and spatial orientation. PCS programs can be applied successfully by trained occupational therapists.

Gender differences in cognitive reserve: implication for subjective cognitive decline in women

BACKGROUND

Subjective Cognitive Decline (SCD) is a self-experienced decline in cognitive capacity with normal performance on standardized cognitive tests, showing to increase risk of Alzheimer's Disease (AD). Cognitive reserve seems to influence the progression from SCD to Mild Cognitive Impairment (MCI) and to AD. The aim of our study was to investigate gender differences in cognitive reserve evaluating how sex might modulate the role of cognitive reserve on SCD.

METHODS

We included 381 SCD patients who underwent clinical evaluation, neuropsychological assessment, evaluation of premorbid intelligence by the Test di Intelligenza Breve (TIB), cognitive complaints by the Memory Assessment Clinics Questionnaire (MAC-Q), and apolipoprotein E (APOE) genotyping.

RESULTS

The proportion between women and men was significantly different (68.7% [95% CI 63.9-73.4 vs 31.4%, 95% CI 26.6-36.0]). Women were younger than men at onset of SCD and at the baseline visit (p = 0.021), had lower years of education (p = 0.007), lower TIB scores (p < 0.001), and higher MAC-Q scores (p = 0.012). TIB was directly associated with age at onset of SCD in both women and men, while years of education was inversely associated with age at onset only in women. Multivariate analysis showed that sex influences TIB independently from years of education. TIB was directly associated with MAC-Q in men.

CONCLUSIONS

Sex interacts with premorbid intelligence and education level in influencing the age at onset and the severity of SCD. As the effect of education was different between men and women, we speculated that education might act as a minor contributor of cognitive reserve in women.

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.

Short-term memory, attention, and temporal orientation as predictors of the cognitive impairment in older adults: A cross-sectional observational study

Late-life cognitive decline ranges from the mildest cases of normal, age-related change to mild cognitive impairment to severe cases of dementia. Dementia is the largest global burden for the 21st century welfare and healthcare systems. The aim of this study was to analyze the neuropsychological constructs (temporal orientation (TO), spatial orientation (SO), fixation memory (FM), attention (A), calculation (C), short-term memory (STM), language (L), and praxis (P)), semantic fluency, level of functionality, and mood that reveal the greatest deficit in the different stages ranging from normal cognition (NC) to cognitive impairment in older adults in a primary healthcare setting. The study included 337 participants (102 men, 235 women), having a mean age of 74 ± 6 years. According to their scores on the Spanish version of the Mini-Mental State Examination (MEC-35), subjects were divided into 4 groups: no deterioration (ND) (score 32-35), subtle cognitive impairment (SCI) (score 28-31), level deterioration (LD) (score 24-27) and moderate deterioration (MD) (score 20-23). The ND group revealed significant differences in TO, STM, C, A, L, P, and S-T as compared to the other groups. The MD group (in all the neuropsychological constructs) and the ND and SCI groups showed significant differences on the Yesavage geriatric depression scale (GDS-15). All except the FM neuropsychological construct were part of the MEC-35 prediction model and all of the regression coefficients were significant for these variables in the model. Furthermore, the highest average percentage of relative deterioration occurs between LD and MD and the greatest deterioration is observed in the STM for all groups, including A and TO for the LD and MD groups. Based on our findings, community programs have been implemented that use cognitive stimulation to prevent cognitive decline and to maintain the neuropsychological constructs.

Education, APOE ε4, and Cognition in Individuals with Subjective Cognitive Decline with Worry in the SILCODE Study

BACKGROUND

Education could offer a protective effect on cognition in individuals with Subjective Cognitive Decline (SCD), which is considered to be the early stage of Alzheimer's Disease (AD). However, the effect of education on cognition in SCD individuals with SCD-plus features is not clear.

OBJECTIVE

The aim of the study was to explore the effect of education on cognition in SCD individuals with SCD-plus features.

METHODS

A total of 234 individuals with SCD were included from the Sino Longitudinal Study on Cognitive Decline (SILCODE). Cognition was assessed across 4 domains (memory, executive, language, and general cognitive functions). Multiple linear regression models were constructed to examine the effect of education on cognitive scores in individuals without worry (n=91) and with worry (n=143). Furthermore, we assessed differences in effects between APOE ε4 noncarriers and APOE ε4 carriers in both groups.

RESULTS

Multiple linear regression analysis showed a positive effect of education on memory, executive, and language cognition in individuals without worry and all cognitive domains in individuals with worry. Furthermore, we found a positive effect of education on executive cognition in APOE ε4 noncarriers without worry and language and general cognition in APOE ε4 carriers without worry. Meanwhile, education had a positive effect on all cognitive domains in APOE ε4 noncarriers with worry and executive, language, and general cognition in APOE ε4 carriers with worry.

CONCLUSION

This study indicates that education has the potential to delay or reduce cognitive decline in SCD individuals with SCD-plus features.

Operational Determination of Subjective Cognitive Decline, Mild Cognitive Impairment, and Dementia Using Sum of Boxes of the Clinical Dementia Rating Scale

Objectives: The Clinical Dementia Rating (CDR) Scale is the gold standard for the staging of dementia due to Alzheimer's disease (AD). However, the application of CDR for the staging of subjective cognitive decline (SCD) and mild cognitive impairment (MCI) in AD remains controversial. This study aimed to use the sum of boxes of the CDR (CDR-SB) plus an SCD single questionnaire to operationally determine the different stages of cognitive impairment (CI) due to AD and non-AD. Methods: This was a two-phase study, and we retrospectively analyzed the Show Chwan Dementia registry database using the data selected from 2015 to 2020. Individuals with normal cognition (NC), SCD, MCI, and mild dementia (MD) due to AD or non-AD with a CDR < 2 were included in the analysis. Results: A total of 6,946 individuals were studied, including 875, 1,009, 1,585, and 3,447 with NC, SCD, MCI, and MD, respectively. The cutoff scores of CDR-SB for NC/SCD, SCD/MCI, and MCI/dementia were 0/0.5, 0.5/1.0, and 2.5/3.0, respectively. The receiver operating characteristic (ROC) analysis showed that the area under the curve (AUC) values of the test groups were 0.85, 0.90, and 0.92 for discriminating NC from SCD, SCD from MCI, and MCI from dementia, respectively. Compared with the Cognitive Abilities Screening Instrument or the Montreal Cognitive Assessment, the use of CDR-SB is less influenced by age and education. Conclusion: Our study showed that the operational determination of SCD, MCI, and dementia using the CDR-SB is practical and can be applied in clinical settings and research on CI or dementia.

Evaluation of neurotrophic factors and education level as predictors of cognitive decline in alcohol use disorder

Cognitive reserve (CR) is the capability of an individual to cope with a brain pathology through compensatory mechanisms developed through cognitive stimulation by mental and physical activity. Recently, it has been suggested that CR has a protective role against the initiation of substance use, substance consumption patterns and cognitive decline and can improve responses to treatment. However, CR has never been linked to cognitive function and neurotrophic factors in the context of alcohol consumption. The present cross-sectional study aims to evaluate the association between CR (evaluated by educational level), cognitive impairment (assessed using a frontal and memory loss assessment battery) and circulating levels of brain-derived neurotrophic factor (BDNF) and neurotrophin-3 (NT-3) in patients with alcohol use disorder (AUD). Our results indicated that lower educational levels were accompanied by earlier onset of alcohol consumption and earlier development of alcohol dependence, as well as impaired frontal cognitive function. They also suggest that CR, NT-3 and BDNF may act as compensatory mechanisms for cognitive decline in the early stages of AUD, but not in later phases. These parameters allow the identification of patients with AUD who are at risk of cognitive deterioration and the implementation of personalized interventions to preserve cognitive function.

Impact of Cognitive Reserve and Premorbid IQ on Cognitive and Functional Status in Older Outpatients

The study aimed to investigate cross-sectionally the associations of cognitive reserve (CR) and premorbid IQ with cognitive and functional status in a cohort of older outpatients. Additionally, we evaluated the association of CR and premorbid IQ with the worsening of patients' cognitive status at one-year follow-up. We originally included 141 outpatients (mean age 80.31 years); a telephone-based cognitive follow-up was carried out after one year, including 104 subjects (mean age 80.26 years). CR (β = 0.418), premorbid IQ (β = 0.271) and handgrip strength (β = 0.287) were significantly associated with the MMSE score. The cognitive worsening at follow-up was associated with lower CR, lower MMSE score, reduced gait speed and frailty exhibited at baseline. Univariate linear regressions showed that CR was associated with handgrip strength (β = 0.346), gait speed (β = 0.185), autonomy in basic (β = 0.221) and instrumental (β = 0.272) daily activities, and frailty (β = -0.290); premorbid IQ was significantly associated with autonomy in instrumental daily activities (β = 0.211). These findings highlight the need for integrating CR and premorbid IQ with physical and motor measures when appraising predictors of cognitive decline in the elderly population. The study also newly extends the link of CR and premorbid IQ to the functional status in older adults.

The Effect of CAG Repeats within the Non-Pathological Range in the HTT Gene on Cognitive Functions in Patients with Subjective Cognitive Decline and Mild Cognitive Impairment

The Huntingtin gene (HTT) is within a class of genes containing a key region of CAG repeats. When expanded beyond 39 repeats, Huntington disease (HD) develops. Individuals with less than 35 repeats are not associated with HD. Increasing evidence has suggested that CAG repeats play a role in modulating brain development and brain function. However, very few studies have investigated the effect of CAG repeats in the non-pathological range on cognitive performances in non-demented individuals. In this study, we aimed to test how CAG repeats' length influences neuropsychological scores in patients with subjective cognitive decline (SCD) and mild cognitive impairment (MCI). We included 75 patients (46 SCD and 29 MCI). All patients underwent an extensive neuropsychological battery and analysis of HTT alleles to quantify the number of CAG repeats. Results: CAG repeat number was positively correlated with scores of tests assessing for executive function, visual-spatial ability, and memory in SCD patients, while in MCI patients, it was inversely correlated with scores of visual-spatial ability and premorbid intelligence. When we performed a multiple regression analysis, we found that these relationships still remained, also when adjusting for possible confounding factors. Interestingly, logarithmic models better described the associations between CAG repeats and neuropsychological scores. CAG repeats in the HTT gene within the non-pathological range influenced neuropsychological performances depending on global cognitive status. The logarithmic model suggested that the positive effect of CAG repeats in SCD patients decreases as the number of repeats grows.

Cognitive Reserve, Brain Reserve, APOEɛ4, and Cognition in Individuals with Subjective Cognitive Decline in the SILCODE Study

BACKGROUND

Cognitive reserve (CR) and brain reserve (BR) could offer protective effects on cognition in the early stage of Alzheimer's disease (AD). However, the effects of CR or BR on cognition in individuals with subjective cognitive decline (SCD) are not clear.

OBJECTIVE

To explore the effects of CR and BR on cognition in subjects with SCD.

METHODS

We included 149 subjects from the Sino Longitudinal Study on Cognitive Decline (SILCODE) study. Education was used as a proxy for CR, and head circumference was used as a proxy for BR. Multiple linear regression models were conducted to examine the effects of CR and BR on cognitive scores. Furthermore, we assessed differences in effects between APOEɛ4 carriers with SCD (n = 35) and APOEɛ4 non-carriers with SCD (n = 114) and linear trends among 4 reserve levels (low BR/CR, high BR/low CR, low BR/high CR, and high BR/high CR).

RESULTS

Both CR and BR had independent positive effects on multiple cognitive measures in SCD participants, and the effects of CR were greater than those of BR. CR has positive effects on cognitive measures in both APOEɛ4 carriers and non-carriers with SCD. However, the positive effects of BR on cognitive measures were observed in APOEɛ4 non-carriers with SCD but not in APOEɛ4 carriers with SCD. Furthermore, there was a linear trend toward better cognitive performance on all cognitive measures in the BR+/CR+ group, followed by the BR-/CR+, BR+/CR-, and BR-/CR-groups.

CONCLUSION

This study suggests that both CR and BR have the potential to delay or slow cognitive decline in individuals with SCD.

Dual Effect of PER2 C111G Polymorphism on Cognitive Functions across Progression from Subjective Cognitive Decline to Mild Cognitive Impairment

BACKGROUND

Periodic circadian protein homolog 2 (PER2) has a role in the intracellular signaling pathways of long-term potentiation and has implications for synaptic plasticity. We aimed to assess the association of PER2 C111G polymorphism with cognitive functions in subjective cognitive decline (SCD).

METHODS

Forty-five SCD patients were included in this study. All participants underwent extensive neuropsychological investigation, analysis of apolipoprotein E (APOE) and PER2 genotypes, and neuropsychological follow-up every 12 or 24 months for a mean time of 9.87 ± 4.38 years.

RESULTS

Nine out of 45 patients (20%) were heterozygous carriers of the PER2 C111G polymorphism (G carriers), while 36 patients (80%) were not carriers of the G allele (G non-carriers). At baseline, G carriers had a higher language composite score compared to G non-carriers. During follow-up, 15 (34.88%) patients progressed to mild cognitive impairment (MCI). In this group, we found a significant interaction between PER2 G allele and follow-up time, as carriers of G allele showed greater worsening of executive function, visual-spatial ability, and language composite scores compared to G non-carriers.

CONCLUSIONS

PER2 C111G polymorphism is associated with better language performance in SCD patients. Nevertheless, as patients progress to MCI, G allele carriers showed a greater worsening in cognitive performance compared to G non-carriers. The effect of PER2 C111G polymorphism depends on the global cognitive status of patients.

Cognitive Phenotypes of Older Adults with Subjective Cognitive Decline and Amnestic Mild Cognitive Impairment: The Czech Brain Aging Study

OBJECTIVE

To compare cognitive phenotypes of participants with subjective cognitive decline (SCD) and amnestic mild cognitive impairment (aMCI), estimate progression to MCI/dementia by phenotype and assess classification error with machine learning.

METHOD

Dataset consisted of 163 participants with SCD and 282 participants with aMCI from the Czech Brain Aging Study. Cognitive assessment included the Uniform Data Set battery and additional tests to ascertain executive function, language, immediate and delayed memory, visuospatial skills, and processing speed. Latent profile analyses were used to develop cognitive profiles, and Cox proportional hazards models were used to estimate risk of progression. Random forest machine learning algorithms reported cognitive phenotype classification error.

RESULTS

Latent profile analysis identified three phenotypes for SCD, with one phenotype performing worse across all domains but not progressing more quickly to MCI/dementia after controlling for age, sex, and education. Three aMCI phenotypes were characterized by mild deficits, memory and language impairment (dysnomic aMCI), and severe multi-domain aMCI (i.e., deficits across all domains). A dose-response relationship between baseline level of impairment and subsequent risk of progression to dementia was evident for aMCI profiles after controlling for age, sex, and education. Machine learning more easily classified participants with aMCI in comparison to SCD (8% vs. 21% misclassified).

CONCLUSIONS

Cognitive performance follows distinct patterns, especially within aMCI. The patterns map onto risk of progression to dementia.

Serum alkaline phosphatase is elevated and inversely correlated with cognitive functions in subjective cognitive decline: results from the ReGAl 2.0 project

BACKGROUND

Alkaline phosphatase has been found on neuronal membranes and plasma alkaline phosphatase (ALP) activity increases during brain injury and cerebrovascular diseases, suggesting that its levels may reflect the neuronal loss. It is known that ALP is higher in subjects affected by Alzheimer's dementia and inversely correlated with cognitive functions. No study has investigated the relationship between ALP and cognitive functions in old-age subject with pre-clinical cognitive impairment.

METHODS

This is a cross-sectional study with data gathered from the ReGAl 2.0 project (Rete Geriatrica Alzheimer-Geriatric Network on Alzheimer's disease), a large Italian multicentric clinical-based study. A cohort of 209 old-age subjects healthy controls (HC), Subjective cognitive decline (SCD), and Mild Cognitive Impairment (MCI) was included in the study. Cognitive performances were assessed with a large neuropsychological battery. The same day, serum alkaline phosphatase activity was measured in all subjects.

RESULTS

We found that the SCD group had significantly higher ALP levels as compared with HC (p = 0.001). Among all neuropsychological tests, in all population ALP levels negatively correlated with scores at attentional matrices (r =  - 0.243, p = 0.002), Digit Span Forward (r =  - 0.241, p = 0.003) and Letter Fluency Test (r =  - 0.196, p = 0.044). Attentional Matrices (r =  - 0.208, p = 0.014) and Letter Fluency Test (r =  - 0.229, p = 0.019) remained significantly correlated with ALP even after controlling for gender. In the SCD group, only the Attentional Matrices significantly and negatively correlated with ALP (r =  - 0.344 p = 0.035), while no significant correlations were found in HC or MCI.

CONCLUSIONS

Results indicate that serum alkaline phosphatase activity is increased in SCD and inversely correlates with cognitive functions. Further studies are needed to investigate the role of ALP in the progression to AD.

Cognitive Reserve, Alzheimer's Neuropathology, and Risk of Dementia: A Systematic Review and Meta-Analysis

Cognitive reserve (CR) may reduce the risk of dementia. We summarized the effect of CR on progression to mild cognitive impairment (MCI) or dementia in studies accounting for Alzheimer's disease (AD)-related structural pathology and biomarkers. Literature search was conducted in Web of Science, PubMed, Embase, and PsycINFO. Relevant articles were longitudinal, in English, and investigating MCI or dementia incidence. Meta-analysis was conducted on nine articles, four measuring CR as cognitive residual of neuropathology and five as composite psychosocial proxies (e.g., education). High CR was related to a 47% reduced relative risk of MCI or dementia (pooled-hazard ratio: 0.53 [0.35, 0.81]), with residual-based CR reducing risk by 62% and proxy-based CR by 48%. CR protects against MCI and dementia progression above and beyond the effect of AD-related structural pathology and biomarkers. The finding that proxy-based measures of CR rivaled residual-based measures in terms of effect on dementia incidence underscores the importance of early- and mid-life factors in preventing dementia later.

How Does Participation in Formal Education or Learning for Older People Affect Wellbeing and Cognition? A Systematic Literature Review and Meta-Analysis

Objective: To determine the effect of later-life formal education or learning on quality of life (QOL), wellbeing, mood, and cognition. Methods: A systematic literature review of interventional clinical trials and observational studies was conducted for adults aged ≥55 years who had undertaken formal education or learning programs. Outcome measures included physical activity, happiness, affective and behavioral symptoms, cognitive function, and QOL. Bias was assessed using funnel plots, Egger’s test, and leave1out analysis. Results: From 32 studies identified, we showed qualitative increases in cognitive function, life satisfaction, and self-confidence associated with learning. A meta-analysis revealed a significant pooled mean difference in MMSE scores (0.40, 95% confidence intervals = [0.12, 0.67]). Although there was a low risk of publication bias there was a high risk of sampling bias. Conclusion: Participation in formal education or learning contributed to increased wellbeing, QOL, healthy cognitive function, self-dependency, and a sense of belonging in older adults.

Lifelong Bilingualism Functions as an Alternative Intervention for Cognitive Reserve Against Alzheimer's Disease

Bilingualism has been reported to significantly delay the onset of dementia and plays an important role in the management of Alzheimer's disease (AD), a condition inducing impairment in the brain network and cognitive decline. Cognitive reserve is associated with the adaptive maintenance of neural functions by protecting against neuropathology. Bilingualism acts as a beneficial environmental factor contributing to cognitive reserve, although some potential confounding variables still need further elucidation. In this article, the relationship between bilingualism and cognitive reserve is discussed, interpreting the advantage of bilingualism in protecting against cognitive decline. In addition, the possible brain and biochemical mechanisms, supporting the advantageous effects of bilingualism in delaying the onset of dementia, involved in bilingualism are reviewed. Effectively, bilingualism can be considered as a pharmacological intervention with no side effects. However, the investigation of the pharmacological parameters of bilingualism is still at an early stage.

PER2 C111G polymorphism, cognitive reserve and cognition in subjective cognitive decline and mild cognitive impairment: a 10-year follow-up study

BACKGROUND AND PURPOSE

CLOCK and PER2 genes have been implicated in sleep-wake cycle alterations and neurodegenerative diseases. Our aim was to evaluate the effect of CLOCK T3111C and PER2 C111G on cognitive functioning in subjective cognitive decline (SCD) patients and mild cognitive impairment (MCI) patients at the baseline of a longitudinal study, and the effect of these two polymorphisms on the progression to Alzheimer's disease (AD) of the two groups.

METHODS

Sixty-eight subjects (41 SCD and 27 MCI) who underwent clinical evaluation, neuropsychological assessment, CLOCK and PER2 genotyping at baseline and neuropsychological follow-up every 2 years for a mean time of 10 years were included. Subjects who developed AD (SCD-c and MCI-c) and non-converters (SCD-nc, MCI-nc) were considered.

RESULTS

CLOCK T3111C was detected in 47% of cases (21 SCD, 11 MCI) and PER2 C111G in 19% of cases (eight SCD and five MCI). PER2 G carriers presented lower premorbid intelligence score (P = 0.049), fewer years of education (P = 0.007) and a lower frequency of family history of AD (P = 0.04) than G non-carriers. MCI PER2 G carriers had worse performance in tests assessing memory, executive function, language and visuospatial abilities at baseline. During follow-up, two SCD and 15 MCI subjects progressed to AD: both of the SCD-c subjects presented the PER2 G allele, while none of the SCD PER2 G non-carriers converted to AD (P = 0.003).

CONCLUSION

PER2 seems to have a role in cognitive reserve and cognition in SCD and MCI patients. Nevertheless, further studies are needed to assess the role of PER2 C111G on the risk of progression to AD.

Impact of cognitive reserve on clinical and neuropsychological measures in patients with mild cognitive impairment

OBJECTIVE

Cognitive reserve influences age of onset, speed of progression, and clinical manifestations of Alzheimer's disease. We investigated whether cognitive reserve interacts with clinical and neuropsychological parameters in mild cognitive impairment (MCI).

METHODS

In this cross-sectional study, we recruited 273 people (70.6 ± 10.1 years, 54.6% women) suffering from subjective memory complaints (n = 65), MCI (n = 121), or dementia (n = 87). Patients underwent neuropsychological evaluation, laboratory testing, and brain imaging. Additionally, we obtained information on years of education and help-seeking motivation.

RESULTS

MCI patients with a university degree were significantly older than those without (71.6 ± 9.6 vs. 66.9 ± 10.3, p = 0.02). University-educated MCI patients demonstrated superior performance in verbal fluency. Intrinsic help-seeking motivation (self-referral) was associated with higher cognitive reserve. Female MCI patients presented with greater intrinsic motivation.

CONCLUSION

Cognitive reserve modulates clinical and neuropsychological measures in patients with MCI.

Association of lifespan cognitive reserve indicator with the risk of mild cognitive impairment and its progression to dementia

INTRODUCTION

The association of lifespan cognitive reserve (CR) with mild cognitive impairment (MCI) remains controversial. We aimed to examine the association of lifespan CR indicator with the risk of MCI and its progression to dementia, taking brain pathologies into account.

METHODS

In a community-based cohort study (mean age, 79 years) with annual follow-up (median, 5.16 years; maximum, 20 years), a cognitively intact group (n = 1182) and an MCI group (n = 420) were identified at baseline. During the follow-up, 611 participants died and underwent autopsies. CR indicator encompassing education, early life to late-life cognitive and social activities were obtained and tertiled.

RESULTS

The multi-adjusted hazard ratio (HR) of MCI was 0.72 (95% confidence interval [CI] 0.58 to 0.90) in the cognitively intact group, and the HR of dementia was 0.66 (95% CI 0.45 to 0.97) in the MCI group for participants with the highest CR indicator (reference: the lowest CR indicator). Among MCI participants with brain pathologies, dementia incidence was about 50% lower in people with the highest CR indicator than the lowest CR indicator.

DISCUSSION

High lifespan CR indicator reduces risk of MCI, and delays its progression to dementia.

The implication of BDNF Val66Met polymorphism in progression from subjective cognitive decline to mild cognitive impairment and Alzheimer's disease: a 9-year follow-up study

Brain-derived natriuretic factor (BDNF) Val66Met polymorphism has been frequently reported to be associated with Alzheimer's disease (AD) with contrasting results. Numerous studies showed that Met allele increased the risk of AD only in women, while other studies have found worse cognitive performance in Val/Val carriers. We aimed to inquire the effects of Val66Met polymorphism on the progression from subjective cognitive decline (SCD) to mild cognitive impairment (MCI) and from MCI to AD and to ascertain if this effect is modulated by demographic and cognitive variables. For this purpose, we followed up 74 subjects (48 SCD, 26 MCI) for a mean time of 9 years. All participants underwent extensive neuropsychological assessment, cognitive reserve estimation, BDNF and apolipoprotein E (ApoE) genotype analysis at baseline. Personality traits and leisure activities were assessed in a subgroup. Each patient underwent clinical-neuropsychological follow-up, during which 18 out of 48 SCD subjects progressed to MCI and 14 out of 26 MCI subjects progressed to AD. We found that Val66Met increased the risk of progression from SCD to MCI and from MCI to AD only in women. Nevertheless, Val/Val carriers who progressed from SCD to MCI had a shorter conversion time compared to Met carriers. We concluded that Val66Met polymorphism might play different roles depending on sex and stage of the disease.

Influence of ApoE Genotype and Clock T3111C Interaction with Cardiovascular Risk Factors on the Progression to Alzheimer's Disease in Subjective Cognitive Decline and Mild Cognitive Impairment Patients

BACKGROUND

Some genes could interact with cardiovascular risk factors in the development of Alzheimer's disease. We aimed to evaluate the interaction between ApoE ε4 status, Clock T3111C and Per2 C111G polymorphisms with cardiovascular profile in Subjective Cognitive Decline (SCD) and Mild Cognitive Impairment (MCI).

METHODS

We included 68 patients who underwent clinical evaluation; neuropsychological assessment; ApoE, Clock and Per2 genotyping at baseline; and neuropsychological follow-up every 12-24 months for a mean of 13 years. We considered subjects who developed AD and non-converters.

RESULTS

Clock T3111C was detected in 47% of cases, Per2 C111G in 19% of cases. ApoE ε4 carriers presented higher risk of heart disease; Clock C-carriers were more frequently smokers than non C-carriers. During the follow-up, 17 patients progressed to AD. Age at baseline, ApoE ε 4 and dyslipidemia increased the risk of conversion to AD. ApoE ε4 carriers with history of dyslipidemia showed higher risk to convert to AD compared to ApoE ε4- groups and ApoE ε4+ without dyslipidemia patients. Clock C-carriers with history of blood hypertension had a higher risk of conversion to AD.

CONCLUSIONS

ApoE and Clock T3111C seem to interact with cardiovascular risk factors in SCD and MCI patients influencing the progression to AD.

Cognitive reserve and working memory in cognitive performance of adults with subjective cognitive complaints: longitudinal structural equation modeling

OBJECTIVE

To study the influence of cognitive reserve (CR) on cognitive performance of individuals with subjective cognitive complaints (SCCs) within a period of 36 months.

DESIGN

We used a general linear model repeated measures procedure to analyze the differences in performance between three assessments. We used a longitudinal structural equation modeling to analyze the relationship between CR and cognitive performance at baseline and at two follow-up assessments.

SETTING

Participants with SCCs were recruited and assessed in primary care health centers.

PARTICIPANTS

A total of 212 participants older than 50 years with SCCs.

MEASUREMENTS

Cognitive reserve data were collected with an ad hoc questionnaire administered to the subjects in an interview. General cognitive performance (GCP), episodic memory (EM), and working memory (WM) have been evaluated. The Mini-Mental State Examination and the total score of Spanish version of the Cambridge Cognitive Examination evaluated the GCP. Episodic memory was assessed with the Spanish version of the California Verbal Learning. Working memory was evaluated by the counting span task and the listening span task.

RESULTS

The satisfactory fit of the proposed model confirmed the direct effects of CR on WM and GCP at baseline, as well as indirect effects on EM and WM at first and second follow-up. Indirect effects of CR on other cognitive constructs via WM were observed over time.

CONCLUSION

The proposed model is useful for measuring the influence of CR on cognitive performance over time. Cognitive response acquired throughout life may influence cognitive performance in old age and prevent cognitive deterioration, thus increasing processing resources via WM.

Playing Mahjong for 12 Weeks Improved Executive Function in Elderly People With Mild Cognitive Impairment: A Study of Implications for TBI-Induced Cognitive Deficits

Background: Mild cognitive impairment (MCI) is common among elderly people. So far, effective treatment that can stabilize or reverse the cognitive decline associated with MCI is lacking. Recent studies suggest that playing mahjong may improve attention and memory in elderly people. However, its effect on executive function remains unknown.

Methods: 56 elderly people (74.3 ± 4.3 years of age) with MCI from the First Social Welfare the First Nursing Home of Nanchong were randomized into mahjong and control groups (N = 28, each group). Subjects in the mahjong group played mahjong three times a week for 12 weeks, while people in the control group assumed normal daily activity. Executive function was evaluated using the Montreal Cognitive Assessment—Beijing (MoCA-B), the Shape Trail Test (STT), and the Functional Activities Questionnaire (FAQ) before the study and then at 6 and 12 weeks after mahjong administration.

Results: There were no baseline differences in MoCA-B, STT, and FAQ scoring between the two groups. The MoCA-B, STT, and FAQ scores, however, improved significantly in the mahjong group but not in the control group after the 12-week mahjong administration. Significant correlations were also found between STT and FAQ scores.

Conclusions: Playing Mahjong for 12 weeks improved the executive function of elderly people with MCI. Because Mahjong is a simple, low-cost entertainment activity, it could be widely applied to slow down or reverse the progression of cognitive decline in people with MCI, including those with traumatic brain injury.

The "SuperAgers" construct in clinical practice: neuropsychological assessment of illiterate and educated elderly

INTRODUCTION

The demographic transition is a global event intensified during the last decades that represents population aging. Thus, the studies directed to the elderly 80 years of age or more with preserved cognitive functions (named SuperAgers) emerges as a possible path to full comprehension of the health of those aging with acceptable levels of functionality and independency.

OBJECTIVE

To evaluate the cognitive performance of the elderly over 80 years old, associating the results to their educational level.

METHOD

We evaluated 144 healthy elders with 80 years or more through the following cognitive tests Mini-Mental State Examination (MMSE), Cambridge Cognitive Examination (CAMCOG), Clock Drawing Test (CDT), and Verbal Fluency Test (VF) and compared the tests' scores with their educational level segmented in years of formal education, being the groups ILLITR (<1 year of schooling), 1TO4 (from 1 to 4 years of schooling), and 5MORE (>5 years of schooling).

RESULTS

There was positive influence of educational level on the cognitive tests' score, which indicates higher cognitive reserve of the elderly with higher educational levels.

CONCLUSION

The functionality and independence of the so-called SuperAgers is determined by the cognitive reserve acquired throughout life, mainly developed by the years of formal education.

Subjective Cognitive Decline Among Sexual and Gender Minorities: Results from a U.S. Population-Based Sample

The risk of dementia and mild cognitive impairment between older adults in same-sex relationships and those in opposite-sex relationships have been found to be statistically not different. However, studies examining subjective cognitive decline (SCD) among sexual and gender minority populations (SGM) are lacking. The primary objective was to determine if SGM report greater SCD compared to non-SGM populations in a U.S. population-based sample of non-institutionalized adults aged 45 and older. The secondary objective was to assess the association between gender and SCD. Cross-sectional data were obtained from the 2016 Behavioral Risk Factor Surveillance System (n = 36,734). There were 1,094 SGM adults in the sample. Descriptive statistics examined sociodemographic characteristics and their distribution by SCD and SGM status. Crude and multivariable logistic regression models were used to determine the association between SGM status, gender, and SCD. Adjusted models controlled for age, race/ethnicity, income, education, employment, marital status, depression, and diabetes. Statistically significant differences in SGM status and SCD existed by age, race/ethnicity, education, employment, marital status, and depression. Differences in SCD also existed by income and diabetes status. There was no statistically significant association between SGM status and SCD (OR: 0.88; 95% CI: 0.63-1.24). However, men had 64% higher odds (OR: 1.64; 95% CI: 1.44-1.88) of reporting SCD compared to women. Future studies examining the potential reasons for this null association, including resilience and/or premature aging are warranted. Future research assessing potential reasons for gender differences in SCD, whether physiological or environmental, is also needed.

Effects of computerised cognitive training on cognitive impairment: a meta-analysis

INTRODUCTION

Computerised cognitive training (CCT) has been shown to enhance cognitive function in elderly individuals with cognitive deterioration, but evidence is controversial. Additionally, whether specific CCT is most effective and which stages of cognitive impairment benefit most is unclear.

METHODS

We systematically searched nine medical and technological databases to collect randomized controlled trials related to CCT primarily conducted in patients with subjective cognitive decline (SCD) and mild cognitive impairment (MCI).

RESULTS

We identified 12 studies in patients with SCD and MCI. Pooled analysis showed that CCT could significantly improve cognitive function (g = 0.518, p = 0.000), especially related to memory. In terms of different types of cognitive training, specific CCT was more efficacious than non-specific CCT (g = 0.381, p = 0.007) or placebo (g = 0.734, p = 0.000) but not traditional CT (p = 0.628). In terms of stages of cognitive deterioration, the effect of CCT on SCD (g = 0.926, p = 0.002) was almost double that of its effect on MCI (g = 0.502, p = 0.000).

CONCLUSION

CCT was most effective in cognitive rehabilitation, particularly in the subdomain of memory. Early intervention in SCD is better.