Measuring Cognitive Reserve (CR) - A systematic review of measurement properties of CR questionnaires for the adult population

Investigation of risk of Alzheimer's disease diagnosis and survival based on variation to life experiences used to operationalize cognitive reserve

BackgroundAlzheimer's disease dementia (AD) is a debilitating progressive neurodegenerative disease. Life experiences are hypothesized to build cognitive reserve (CR), a theoretical construct associated with delayed onset of AD symptoms. While CR is a key moderator of cognitive decline, operationalization of CR is varied resulting in inconsistencies within the literature.ObjectiveThis study explored the relationship between life experiences used as proxies of CR and risk of AD diagnosis and death following diagnosis.MethodsWe explored results based on 30 different published CR operationalizations, including two standardized questionnaires and an investigator-developed lifecourse indicator. Using data from the Memory and Aging Project, we applied Cox proportional hazard models to evaluate the impact of operationalization on time to outcomes.ResultsHazard ratios, indicating instantaneous risk of AD or death for a standard deviation increase in the CR proxy utilized as a predictor, ranged from 0.80-1.40 for AD diagnosis and 0.80-1.29 for death following diagnosis. Among nine predictors that showed a significant reduction in risk of AD, there was a decrease of between 12% and 20%. Two predictors were associated with reduced risk of death, with 13%-20% reduction, while three predictors were associated with 18%-22% heightened risk of death following diagnosis.ConclusionsModel results were highly sensitive to CR operationalization. Based on the variation in results, composite measures that incorporate multiple lifecourse variables may still be the most comprehensive and faithful representation of CR. Attention to methodology and refining of measurement are needed to make use of CR and promote healthy aging.

Cognitive reserve moderates the effect of COVID-19 on cognition: A systematic review and meta-analysis of individual participant data

Elucidating the factors that mitigate the effects of COVID-19 on cognitive function offers important insights for public health policy and intervention. This systematic review and individual participant data (IPD) meta-analysis assesses cognitive reserve (CR) as a potential moderator of post-COVID-19 cognitive dysfunction (PCCD). Under PRISMA-IPD guidelines, data searches were conducted via PubMed, PsycINFO, Scopus, and Embase, up to January 2023. Eligible studies included at least one cognitive assessment, CR proxy, and disease severity indicator. Of 5604 studies, 87 were eligible (10,950 COVID-19 cases; 78,305 controls), and IPD was obtained for 29 datasets (3919 COVID-19 cases; 8267 controls). Three-level random-effects meta-analyses indicated that CR had a moderate positive association (rsp =.29), and COVID-19 severity had a small negative association (rsp = -.07) with cognitive outcomes. These effects were moderated by a significant within-study interaction. Cognitive deficits following COVID-19 were 33 % smaller among high CR individuals, and 33 % greater among low CR individuals, relative to those with average CR. Population-based initiatives promoting reserve-building behaviors may alleviate the PCCD-related public health burden. REVIEW REGISTRATION: PROSPERO registration number: CRD42022360670.

Age-invariant approaches to cognitive reserve

Cognitive reserve (CR) and its measurement by proxies have gained interest in cognitive aging research. While CR proxies seem valuable for predicting cognitive function, their measures are often conflated with age effects. The current study aims to address this by introducing an age-invariant approach of CR. We included 380 participants (age = 18-79) from the Advanced Brain Imaging on aging and Memory (ABRIM) study who completed the Cognitive Reserve Index questionnaire (CRIq), a measure to estimate verbal IQ, and several neuropsychological tasks in the domains of memory, executive function and attention/speed. With various regression models and structural equation modeling, we assessed age effects on the CRIq subscales and their predictive value on cognitive function. Results showed a significant non-linear age effect on the Education and Occupation subscale of the CRIq and a linear age effect on the Leisure subscale. New age-corrections derived from these effects were more accurate than age-corrections from the original norm scores. Moreover, the three cognitive domains were significantly predicted in the expected direction by the new age-corrected CRIq scores, and not by the raw scores or original age-corrected scores. However, compared to verbal IQ, the predictive value of these CRIq scores was still low. Associations between the CRIq and cognitive function seemed to vary across the lifespan, but were not consistently stronger for older adults. These findings illustrate the importance of age adjustments in CR research. Most importantly, appropriate age-adjustments may be sample specific and non-linear effects to properly correct for age must be considered.

Environmental enrichment is associated with favorable memory-related functional brain activity patterns in older adults

Background

In humans, environmental enrichment (EE), as measured by the engagement in a variety of leisure activities, has been associated with larger hippocampal structure and better memory function. The present cross-sectional study assessed whether EE during early life (13-30 years) and midlife (30-65 years) is associated with better preserved memory-related brain activity patterns in older age.

Methods

In total, 372 cognitively unimpaired older adults (aged ≥60 years old) of the DZNE-Longitudinal Study on Cognitive Impairment and Dementia (DELCODE; DRKS00007966) were investigated. EE was operationalized using items of the Lifetime of Experiences Questionnaire (LEQ), which measures the self-reported participation in a variety of leisure activities in early life and midlife. The preservation of memory-related functional brain activity was assessed using single-value scores, which relate older adults' brain activity patterns in the temporo-parieto-occipital memory network to those of young adults during visual memory encoding (FADE and SAME scores).

Results

EE during early life and midlife was significantly associated with higher SAME scores during novelty processing (n = 372, β = 0.13, p = 0.011). Thus, older participants with higher EE showed greater similarity of functional brain activity patterns during novelty processing with young adults. This positive association was observed most strongly in participants with subjective cognitive decline (SCD, n = 199, β = 0.20, p = 0.006).

Conclusion

More frequent participation in a variety of leisure activities in early life and midlife is associated with more successful aging of functional brain activity patterns in the memory network of older adults, including participants at increased risk for dementia. Longitudinal studies are needed to clarify whether higher EE during life could help preserve memory network function in later life.

A measure of modifiable lifestyle factors shaping subjective cognitive reserve in the general population

Objective

This study examined the psychometric properties of a newly developed scale for measuring subjective cognitive reserve (SCR) across multiple domains, including nutrition, physical condition, sleep, cognition, willingness to learn, socialization, general health, and life plan.

Method

The relationship between SCR scores and other established measures of cognitive reserve and subjective cognitive decline was also explored. A sample of 402 healthy participants aged 18 to 79 years took part in the study.

Results

The SCR scale demonstrated strong psychometric properties, including internal consistency and construct validity, supporting the theoretical model of perceived cognitive reserve. Convergent validity was confirmed through a positive correlation between SCR scores and resilience (BRCS) as well as with other cognitive reserve measures, indicating consistency in evaluating cognitive reserve across various instruments. Furthermore, discriminant validity was demonstrated by a significant negative correlation between SCR scores and subjective cognitive decline, suggesting that individuals with higher cognitive reserve experience lower levels of perceived cognitive decline. No significant relationship was found between SCR scores and chronological age, further supporting the construct validity of the scale by showing that cognitive reserve is influenced by dynamic factors beyond age.

Conslusion

The findings highlight the potential of the SCR scale as a reliable and valid tool for assessing cognitive reserve and its protective role in cognitive health and well-being over time.

Cognitive engagement may slow clinical progression and brain atrophy in Huntington's disease

Lifelong cognitive engagement conveys benefits in Huntington's disease (HD) and may positively affect non-cognitive domains in other populations. However, the effect of lifelong cognitive engagement on the progression of motor and psychiatric domains in HD remains unknown, as is its neurobiological basis. Forty-five HD individuals completed the Cognitive Reserve Questionnaire (CRQ) and longitudinal clinical evaluation (maximum total of six visits, mean inter-assessment duration of 13.53 ± 4.1 months). Of these, thirty-three underwent longitudinal neuroimaging (18 ± 6 months follow-up). Generalized linear mixed-effects models were executed to predict the effect of individual differences in lifelong cognitive engagement on HD clinical progression and voxel-based morphometry to explore the impact of lifelong cognitive engagement on whole-brain gray matter volume atrophy. Controlling for age, disease stage, and sex, higher CRQ scores were associated with reduced overall severity and longitudinal progression across cognitive, motor, and psychiatric domains. Those with higher CRQ scores demonstrated reduced gray matter volume loss in the middle frontal gyrus, supplementary motor area, and middle cingulate. This putative impact on HD clinical progression may be conferred by preservation of brain volume in neural hubs that integrate executive function with action initiation and behavioral regulation, providing support for early cognitive engagement, even prior to diagnosis.

Cognitive reserve in individuals with frontotemporal dementia: a systematic review

As the literature related to cognitive reserve (CR) in individuals with frontotemporal dementia (FTD) is only emerging, a clear consensus on the relationship among CR proxies, brain status, and clinical performance has not been reached. The primary aim of this systematic review was to examine the relationship among sociobehavioral proxies of CR, brain status, and clinical performance in individuals with various types of FTD. Additionally, characteristics of patient population, sociobehavioral proxies, disease severity tools, and brain status measures used were identified. The systematic review was conducted using comprehensive search terms in Medline, PsychINFO, PubMed, and Web of Science. Eligibility criteria were for studies to include at least one CR and one brain status measure for individuals with FTD, be published in a peer-reviewed journal, and be published in English. The Newcastle-Ottawa Quality Assessment Scale was used to assess study quality and bias risk. A total of 237 titles and abstracts were screened, with 13 studies meeting inclusion criteria. Together, these studies report 1,423 participants with FTD. Based on the included studies, partial support was demonstrated for CR in individuals with FTD when education, occupation, and leisure were utilized as CR proxies. The variability in results among studies could be related to the different tools used to measure CR, brain status, and disease severity. This review provides recommendations for future studies: incorporating longitudinal designs, in depth neuropsychological testing, consistent disease duration measure, and transparant statistical output reporting.

Cognitive profiles in the acute phase of traumatic brain injury according to injury severity

Although several studies have documented the chronic phase of traumatic brain injury (TBI), few verified the nature and severity of cognitive impairments during the acute phase. Among the studies carried out during the acute phase, instrumental functions were rarely examined compared to attention, memory, and executive functions. This study aimed to compare the nature and intensity of cognitive problems in the acute phase according to TBI severity and age. It was hypothesized that cognitive impairments would increase in line with TBI severity and age, and that instrumental functions would be less affected in victims of mild or moderate TBI than in those with severe TBI. The Brief Cognitive Exam in Traumatology (EXACT), a new and reliable test specifically designed and validated to briefly assess global cognitive functioning during the acute phase, was administered to 319 mild to severe TBI victims (aged 16 to 96 years), within three months post-accident. The EXACT evaluates five domains: Language, Instrumental functions (other than language), Attention and working memory, Episodic memory, and Executive functions and behavioral regulation. Results confirmed the negative influence of TBI severity and age on global cognitive functioning. Also, compared to victims with a mild or moderate TBI, a higher proportion of those with a severe TBI presented impaired instrumental functions (calculation, praxis, and gnosis). Thus, during the acute phase, the nature and severity of cognitive impairments vary according to TBI severity.

Patients' Cognitive Potential Is Associated With Cognitive Performance After an Acute Course of Electroconvulsive Therapy

OBJECTIVES

Cognitive function after an acute treatment of electroconvulsive therapy (ECT) can highly vary between individuals. This study aimed to extend prior research on individual factors, which influence outcomes by assessing whether a combination of 2 individual factors, level of education and lifetime occupational attainment, may be informative.

METHODS

A retrospective study was conducted using data from 24 patients with major depressive episode who underwent acute treatment with ECT. Cognitive functioning was assessed at pretreatment, during the acute course and 1-3 days after acute treatment. Participants were divided into higher and lower function groups based on a combination of their highest educational level and lifetime occupational attainment.

RESULTS

Statistically significant differences were observed between the 2 groups in retrograde memory function after ECT, assessed as percentage of consistency scores of the Columbia Autobiographical Memory Short Form (F(1,15) = 4.66, P < 0.05) and recovery of orientation during the acute ECT course (F(1,25.33) = 7.99, P = 0.009). No significant differences were found between groups for the other outcomes, which included verbal and visual anterograde memory, verbal fluency, and processing speed.

CONCLUSIONS

Results from this preliminary study suggest that patients with higher educational and lifetime occupational attainment may experience less retrograde amnesia and have faster recovery of orientation after ECT. Identifying markers of higher and lower 'cognitive potential' before ECT may assist in customizing ECT treatment for each patient.

Mid- and late-life lifestyle activities as main drivers of general and domain-specific cognitive reserve in individuals with Parkinson's disease: cross-sectional and longitudinal evidence from the LANDSCAPE study

BACKGROUND

Cognitive reserve (CR) is considered a protective factor for cognitive function and may explain interindividual differences of cognitive performance given similar levels of neurodegeneration, e.g., in Alzheimer´s disease. Recent evidence suggests that CR is also relevant in Parkinson's disease (PD).

OBJECTIVE

We aimed to explore the role of life-stage specific CR for overall cognition and specific cognitive domains cross-sectionally and longitudinally in PD.

METHODS

The cross-sectional analysis with data from the DEMPARK/LANDSCAPE study included 81 individuals without cognitive impairment (PD-N) and 87 individuals with mild cognitive impairment (PD-MCI). Longitudinal data covered 4 years with over 500 observations. CR was operationalized with the Lifetime of Experiences Questionnaire (LEQ), capturing the complexity of lifestyle activities across distinct life-stages. Cognition was assessed using a comprehensive neuropsychological test battery.

RESULTS

Higher LEQ scores, particularly from mid- and late-life, were observed in PD-N compared to PD-MCI [F(1,153) = 4.609, p = .033, ηp2 = 0.029]. They were significantly associated with better cognitive performance (0.200 ≤ β ≤ 0.292). Longitudinally, linear mixed effect models (0.236 ≤ marginal R2 ≤ 0.441) revealed that LEQ scores were positively related to cognitive performance independent of time. However, the decline in overall cognition and memory over time was slightly more pronounced with higher LEQ scores.

CONCLUSIONS

This study emphasizes the association between complex lifestyle activities and cognition in PD. Data indicate that while CR might be related to a delay of cognitive decline, individuals with high CR may experience a more pronounced drop in overall cognition and memory. Future studies will have to replicate these findings, particularly regarding domain-specific effects and considering reverse causal mechanisms.

A nomogram for individualized prediction of mild cognitive impairment in patients with subjective cognitive decline during physical examinations: a cross-sectional study

Background and objectives

To develop a nomogram for mild cognitive impairment (MCI) in patients with subjective cognitive decline (SCD) undergoing physical examinations in China.

Methods

We enrolled 370 patients undergoing physical examinations at the Medical Center of the First Hospital of Jilin University, Jilin Province, China, from October 2022 to March 2023. Of the participants, 256 were placed in the SCD group, and 74 were placed in the MCI group. The population was randomly divided into a training set and a validation set at a 7:3 ratio. A least absolute shrinkage and selection operator (LASSO) regression model was applied to optimize feature selection for the model. Multivariable logistic regression analysis was applied to construct a predictive model. The performance and clinical utility of the nomogram were determined using Harrell's concordance index, calibration curves, and decision curve analysis (DCA).

Results

Cognitive reserve (CR), age, and a family history of hypertension were associated with the occurrence of MCI. The predictive nomogram showed satisfactory performance, with a concordance index of 0.755 (95% CI: 0.681-0.830) in internal verification. The Hosmer-Lemeshow test results suggested that the model exhibited good fit (p = 0.824). In addition, DCA demonstrated that the predictive nomogram had a good clinical net benefit.

Discussion

We developed a simple nomogram that could help secondary preventive health care workers to identify elderly individuals with SCD at high risk of MCI during physical examinations to enable early intervention.

Cognitive reserve modulates mental health in adulthood

Cognitive Reserve (CR) reflects acquired knowledge, skills, and abilities throughout life, and it is known for modulating cognitive efficiency in healthy and clinical populations. CR, which was initially proposed to explain individual differences in the clinical presentation of dementia, has subsequently been extended to healthy ageing, showing its role in cognitive efficiency also during middle age. Recently, CR has been linked to affective processes in psychiatric conditions such as schizophrenia, major depressive and anxiety symptoms, and psychological distress, suggesting its potential role in emotional expression and regulation. Whether the role of CR in mental health extends to non-pathological adults, and whether this is only relevant in older age is not yet clear. The aim of this work was therefore to explore the relationship between CR and mental health in healthy adults, with a focus on middle adulthood (40-60). In a sample of 96 participants, we found a positive association between CR and mental health outcomes, such that a higher cognitive reserve index corresponded to fewer mental health reported symptoms. Specifically, a higher CR reflecting professional activities was associated with lower stress levels, especially in middle agers. Taken together, these data therefore suggest that engaging occupations may help maintain a robust mental health, especially by reducing stress symptoms during middle age. These results broaden previous findings suggesting that CR relates to affective components of mental health in middle aged and older adults.

The Advanced BRain Imaging on ageing and Memory (ABRIM) data collection: Study design, data processing, and rationale

To understand the neurocognitive mechanisms that underlie heterogeneity in cognitive ageing, recent scientific efforts have led to a growing public availability of imaging cohort data. The Advanced BRain Imaging on ageing and Memory (ABRIM) project aims to add to these existing datasets by taking an adult lifespan approach to provide a cross-sectional, normative database with a particular focus on connectivity, myelinization and iron content of the brain in concurrence with cognitive functioning, mechanisms of reserve, and sleep-wake rhythms. ABRIM freely shares MRI and behavioural data from 295 participants between 18-80 years, stratified by age decade and sex (median age 52, IQR 36-66, 53.20% females). The ABRIM MRI collection consists of both the raw and pre-processed structural and functional MRI data to facilitate data usage among both expert and non-expert users. The ABRIM behavioural collection includes measures of cognitive functioning (i.e., global cognition, processing speed, executive functions, and memory), proxy measures of cognitive reserve (e.g., educational attainment, verbal intelligence, and occupational complexity), and various self-reported questionnaires (e.g., on depressive symptoms, pain, and the use of memory strategies in daily life and during a memory task). In a sub-sample (n = 120), we recorded sleep-wake rhythms using an actigraphy device (Actiwatch 2, Philips Respironics) for a period of 7 consecutive days. Here, we provide an in-depth description of our study protocol, pre-processing pipelines, and data availability. ABRIM provides a cross-sectional database on healthy participants throughout the adult lifespan, including numerous parameters relevant to improve our understanding of cognitive ageing. Therefore, ABRIM enables researchers to model the advanced imaging parameters and cognitive topologies as a function of age, identify the normal range of values of such parameters, and to further investigate the diverse mechanisms of reserve and resilience.

Lower cognitive reserve is related to worse working memory performance in older adults after mTBI. An ERP study

OBJECTIVE

Older adults (OA) after mild traumatic brain injury (mTBI) have a high risk of developing persistent post-injury cognitive impairments. Lower pre-morbid cognitive reserve (CR) is increasingly investigated as a risk factor for cognitive dysfunction in OA. However, how CR protects against effects of mTBI at the brain level remains largely understudied.

METHODS

We examined 22 OA who sustained mTBI (mean 67.69 years, SD 5.11) in the sub-acute phase and 15 age- and CR-matched healthy OA (mean 68 years, SD 5.55) performing a three-level visual N-back task using electroencephalography. We calculated inverse efficiency scores of performance from accuracy and reaction times. Event-related potentials served as neurocognitive correlates of attentional (P2) and working memory (P3) processing.

RESULTS

Overall, mTBI OA performed worse than healthy OA (p = 0.031). Lower CR generally decreased performance (p < 0.001). Furthermore, with increasing task difficulty, task performance was more affected by CR (p = 0.004). At the brain level, P2 amplitude was lower in mTBI OA than in healthy OA (p = 0.05). There was no clear effect of CR on P2 or P3 measures.

CONCLUSION

As mTBI OA with lower CR performed worse on a working-memory task, lower CR may be a risk factor for worse recovery after mTBI in this group.

Cognitive Reserve Potential: Capturing Cognitive Resilience Capability in Adolescence

Cognitive reserve (CR) represents the adaptive response of the cognitive system responsible for preserving normal functioning in the face of brain damage. Experiential factors such as education, occupation, and leisure activities influence the development of CR. Theoretically, such factors build up from childhood and across adulthood. Thus, appropriate tools to define and measure CR as early as adolescence are essential to understand its developmental processes. To this aim, we introduce the construct of "Cognitive Reserve Potential" (CRP) and its corresponding index of experiential factors tailored to youth. We investigated prototypical youth exposures potentially associated with the lifelong development of CR (e.g., sport practice, musical experiences, cultural activities, and relationships with peers and family). Principal component analysis and confirmatory factor analysis identified and replicated the CRP factor structure on two independent samples of Italian students: N = 585 (295 F) and N = 351 (201 F), ages 11 to 20. CRP was associated mainly with family socio-cultural status (i.e., socioeconomic status [SES], Home Possessions, and Books at Home). Results confirmed the strength of the factorial model and warranted the proposal of the CRP-questionnaire as an innovative tool for understanding CR evolutionary dynamics.

Instruments to Assess Cognitive Reserve Among Older Adults: a Systematic Review of Measurement Properties

Cognitive reserve explains the differences in the susceptibility to cognitive impairment related to brain aging, pathology, or insult. Given that cognitive reserve has important implications for the cognitive health of typically and pathologically aging older adults, research needs to identify valid and reliable instruments for measuring cognitive reserve. However, the measurement properties of current cognitive reserve instruments used in older adults have not been evaluated according to the most up-to-date COnsensus-based Standards for the selection of health status Measurement INstruments (COSMIN). This systematic review aimed to critically appraise, compare, and summarize the quality of the measurement properties of all existing cognitive reserve instruments for older adults. A systematic literature search was performed to identify relevant studies published up to December 2021, which was conducted by three of four researchers using 13 electronic databases and snowballing method. The COSMIN was used to assess the methodological quality of the studies and the quality of measurement properties. Out of the 11,338 retrieved studies, only seven studies that concerned five instruments were eventually included. The methodological quality of one-fourth of the included studies was doubtful and three-seventh was very good, while only four measurement properties from two instruments were supported by high-quality evidence. Overall, current studies and evidence for selecting cognitive reserve instruments suitable for older adults were insufficient. All included instruments have the potential to be recommended, while none of the identified cognitive reserve instruments for older adults appears to be generally superior to the others. Therefore, further studies are recommended to validate the measurement properties of existing cognitive reserve instruments for older adults, especially the content validity as guided by COSMIN.Systematic Review Registration numbers: CRD42022309399 (PROSPERO).

Associations between Physical Activity Frequency in Leisure Time and Subjective Cognitive Limitations in Middle-Aged Spanish Adults: A Cross-Sectional Study

There is a global ageing of the world's population. Ageing is associated with multiple pathologies, reductions in physical activity, and losses in cognitive function. This study aimed to analyse the associations between the frequency of leisure-time physical activity (PAF) in middle-aged Spaniards and subjective cognitive limitations (SCLs): self-reported problems for remembering or concentrating (data extracted from the 2017 National Health Survey and the 2020 European Health Survey in Spain). Furthermore, the study aimed to evaluate risk factors that could be related to a higher probability of developing SCLs. This was a cross-sectional study with 15,866 middle-aged Spaniards. The associations between FAP and SCLs were analysed using chi-square. Also, the risk factors for SCLs were evaluated using binary multiple logistic regression. The median age of participants was 55 years, with 49% men and 51% women. Associations were found between PAF and SCLs (p < 0.001). The highest prevalence of SCLs was found in physically inactive people and the lowest in very active people (13.7% vs. 5.8%, p < 0.05), and people with SCLs had a higher prevalence of inactivity than those without SCLs (47.2% vs. 33.8%, p < 0.05). Physical inactivity, low educational level, low social class, and being female were the main risk factors for SCLs. Among the actions to prevent cognitive limitations, as well as interventions in people with cognitive limitations, it would be advisable to include physical activity programmes, both as a preventive measure to delay cognitive limitations and to reduce the risk of other pathologies in people who already have them.

Cognitive resilience/reserve: Myth or reality? A review of definitions and measurement methods

INTRODUCTION

This review examines the concept of cognitive reserve (CR) in relation to brain aging, particularly in the context of dementia and its early stages. CR refers to an individual's ability to maintain or regain cognitive function despite brain aging, damage, or disease. Various factors, including education, occupation complexity, leisure activities, and genetics are believed to influence CR.

METHODS

We revised the literature in the context of CR. A total of 842 articles were identified, then we rigorously assessed the relevance of articles based on titles and abstracts, employing a systematic approach to eliminate studies that did not align with our research objectives.

RESULTS

We evaluate-also in a critical way-the methods commonly used to define and measure CR, including sociobehavioral proxies, neuroimaging, and electrophysiological and genetic measures. The challenges and limitations of these measures are discussed, emphasizing the need for more targeted research to improve the understanding, definition, and measurement of CR.

CONCLUSIONS

The review underscores the significance of comprehending CR in the context of both normal and pathological brain aging and emphasizes the importance of further research to identify and enhance this protective factor for cognitive preservation in both healthy and neurologically impaired older individuals.

HIGHLIGHTS

This review examines the concept of cognitive reserve in brain aging, in the context of dementia and its early stages. We have evaluated the methods commonly used to define and measure cognitive reserve. Sociobehavioral proxies, neuroimaging, and electrophysiological and genetic measures are discussed. The review emphasizes the importance of further research to identify and enhance this protective factor for cognitive preservation.

Longitudinal validation of cognitive reserve proxy measures: a cohort study in a rural Chinese community

BACKGROUND

While evidence supports cognitive reserve (CR) in preserving cognitive function, longitudinal validation of CR proxies, including later-life factors, remains scarce. This study aims to validate CR's stability over time and its relation to cognitive function in rural Chinese older adults.

METHODS

Within the project on the health status of rural older adults (HSRO), the survey included baseline assessment (2019) and follow-up assessment (2022). 792 older adults (mean age: 70.23 years) were followed up. The confirmatory factor analysis (CFA) was constructed using cognitive reserve proxies that included years of formal education, social support, hobbies, and exercise. We examined the longitudinal validity of the CR factor using confirmatory factor analyses and measurement invariance and explored the association of CR with cognition using Spearman's correlation and Generalized Estimating Equations (GEE).

RESULTS

The results showed that CR's CFA structure was stable over time (T0, χ2/df: 3.21/2; RMSEA: 0.02, and T1, χ2/df: 7.47/2; RMSEA: 0.05) and that it accepted both configural and metric invariance (Δχ2/df = 2.28/3, P = 0.52). In addition, it was found that CR had a stable positive relationship with cognitive function across time (T0, r = 0.54; T1, r = 0.49). Furthermore, longitudinal CR were associated with MMSE (β = 2.25; 95%CI = 2.01 ~ 2.49).

CONCLUSIONS

This study provided valuable evidence on the stability and validity of cognitive reserve proxy measures in rural Chinese older adults. Our findings suggested that cognitive reserve is associated with cognitive function over time and highlighted the importance of accumulating cognitive reserve in later life.

Handicraft art leisure activities and cognitive reserve

ObjectiveOlder individuals face a higher likelihood of developing dementia. The rate of cognitive decline resulting from dementia is not equivalent for all, as some patients with dementia are able to function independently longer than others, despite having similar disease burden. The cognitive reserve (CR) theory provides one explanation for the differing rate of decline. CR suggests that there are factors-most notably, educational attainment and occupational attainment-that can protect against the cognitive decline. Although the beneficial effects of these notable CR factors are clear, not all are easily modifiable. Participation in leisure activities may represent a more easily modifiable factor. Some research hints at beneficial effects of leisure activities, although specific leisure activities have not been well examined. The present study examined the relations between handicraft art leisure activities (HALAs) and multiple cognitive domains. MethodArchival WAIS-IV and demographic data for 50 California retirement community residents were examined. ResultsHALA participation accounted for statistically significant variance in working memory performance (R2 = .40, β = .24%) over and above the established CR factors of age, depression, educational attainment, and occupational attainment. In addition, HALA participation was related to a better ability to perform abstract visual information tasks (Block Design subtest, r = .28, p = .05) and non-verbal reasoning tasks (Visual Puzzles subtest, r = .38, p = .008). ConclusionsHALA participation among older adults could contribute to the retention of cognitive function, supporting the role of HALA participation as a CR factor.

Cognitive reserve proxies for individuals with intellectual developmental disability: A scoping review

BACKGROUND

Cognitive reserve (CR) has not been studied in people with Intellectual Developmental Disability, a population with a high incidence of dementia. Commonly adopted CR proxies should be adapted to reflect more specifically the experiences of people with Intellectual Developmental Disability.

METHOD

This scoping review intended to identify CR proxies relevant to people with this condition.

RESULTS

Some of these were the same already detected in a population without intellectual disabilities (education, occupation, physical activity, leisure, community and social activities); others were found to be specifically relevant for this population: type of schooling, parental educational level, environmental stimulation and living place.

CONCLUSIONS

These proxies need to be considered in studies on CR and Intellectual Developmental Disability and in clinical practice. Research on the protective effect of CR aims to encourage policies promoting lifestyle-based educational and preventive interventions and overcome participation barriers for people with Intellectual Developmental Disability.

Cognitive reserve predicts episodic memory enhancement induced by transcranial direct current stimulation in healthy older adults

Episodic memory shows the largest degree of age-related decline. Anodal transcranial Direct Current Stimulation (tDCS) can enhance episodic memory in aging but there is also evidence of response variability even when using identical stimulation parameters. To explore which inter-individual factors (i.e. age, education, encoding performance, cognitive reserve, tDCS group and timing of tDCS application) may directly and/or indirectly modulate verbal memory recall, we used data from our previous tDCS studies that showed enhanced episodic memory recall in 80 healthy older adults. In these studies we used the same paradigm and stimulation parameters but tDCS was applied during different memory stages. Memory recall was tested 48 hours and 30 days after encoding. Univariate regression models showed that tDCS group (Anodal vs. Sham) predicted memory recall, indicating higher scores in the Anodal group than in the Sham group. Encoding performance predicted memory recall in both tDCS groups. Multiple regression models revealed that cognitive reserve, measured with a life experience questionnaire, predicted memory recall only for the Anodal group. Higher cognitive reserve was linked to better memory recall. Accounting for individual differences in cognitive reserve at baseline helps to explain tDCS responsiveness. This knowledge may contribute to optimize its use in older adults.

Unexpected cognitive similarities between older adults and young people: Scores variability and cognitive performances

BACKGROUND

Increased interindividual variability in cognitive performance during aging has been proposed as an indicator of cognitive reserve.

OBJECTIVE

To determine if interindividual variability performance in episodic memory (PAL), working memory (SWM), reaction time (RTI), and sustained attention (RVP) could differentiate clusters of differential cognitive performance in healthy young and older adults and search for cognitive tests that most contribute to these differential performances.

METHODS

We employed hierarchical cluster and canonical discriminant function analyses of cognitive scores using the Cambridge Neuropsychological Test Automated Battery (CANTAB) to identify cognitive variability in older and young adults using the coefficient of variability of cognitive performances between and within groups. We also analyzed potential influences of age, education, and physical activity.

RESULTS

Cluster analysis distinguished groups with differential cognitive performance and correlation analysis revealed coefficient of variability and cognitive performance associations. The greater the coefficient of variability the poorer was cognitive performance in RTI but not in PAL and SWM. Older adults showed diverse trajectories of cognitive decline, and better education or higher percentage of physically active individuals exhibited better cognitive performance in both older and young adults.

CONCLUSION

PAL and SWM are the most sensitive tests to investigate the wide age range encompassing older and young adults. In older adults' intragroup analysis PAL showed greater discriminatory capacity, indicating its potential for clinical applications late in life. Our data underscore the importance of studying variability as a tool for early detection of subtle cognitive declines and for interpreting results that deviate from normality.

Relationship between lifestyle proxies of cognitive reserve and cortical regions in older adults

Introduction

With the rapid increase in the population over 65 years old, research on healthy aging has become one of the priorities in the research community, looking for a cost-effective method to prevent or delay symptoms of mild cognitive disorder or dementia. Studies indicate that cognitive reserve theory could be beneficial in this regard. The aim of this study was to investigate the potential relationship between lifestyle socio-behavioral proxies of cognitive reserve and cortical regions in adults with no subjective cognitive decline.

Methods

Overall, 58 participants, aged 65-85 years, were included in the data analysis (M = 71.83, SD = 5.02, 20.7% male). Cognitive reserve proxies were measured using the Cognitive Reserve Index questionnaire, while cortical volumes were obtained with the Siemens 1.5 T Avanto MRI scanner and further mapped using the Desikan-Killiany-Tourville (DKT) Atlas. Estimated intracranial volume and age were used as covariates.

Results

The results indicated that higher occupational complexity was associated with larger cortical volume in the left middle temporal gyrus, the left and right inferior temporal gyrus, and the left inferior parietal lobule, while a combined proxy (the total CRI score) showed a positive relationship with the volume of left middle temporal gyrus and inferior parietal lobule, and pars orbitalis in the right hemisphere.

Discussion

These results might indicate that more complex occupational activities and overall more intellectually and socially active life-style could contribute to better brain health, especially in regions known to be more vulnerable to Alzheimer's disease.

The role of cognitive reserve in traumatic brain injury: a systematic review of observational studies

OBJECTIVE

Evaluate the role of cognitive reserve (CR) on cognitive and physical sequelae in traumatic brain injury (TBI).

METHODS

A comprehensive search strategy was conducted in four databases in English and Spanish in the last 12 years (2011-2023). Inclusion criteria: original cross-sectional and longitudinal studies whose main or secondary objective was to evaluate the effect of CR in adult patients with TBI. PRISMA guidelines were used to report the search and selection method and STROBE checklist was used to evaluate the quality of studies.

RESULTS

Eighteen observational studies were included in this review. Multiple sources of variability were observed: number of patients, time of evolution, severity of the TBI, type of CR proxy, cognitive assessment instrument, etc. However, the most commonly used indicators of CR were premorbid IQ and educational attainment. A positive and consistent association between CR and performance on cognitive tests after injury was found.

CONCLUSIONS

CR has a consistent positive effect on cognition and on some other aspects of recovery in traumatic brain injury. In future studies, it will be necessary to promote the use of CR indices based on various indicators and explore the effects of CR on other aspects related to the recovery of brain trauma.

The utility of the Cognitive Reserve Index questionnaire in chronic traumatic brain injury

Objective: This study examined the relationship between cognitive reserve measured with the Cognitive Reserve Index questionnaire (CRIq) and cognitive and functional outcomes in a chronic traumatic brain injury (TBI) cohort compared to a non-TBI cohort. The utility of the CRIq was compared to common proxies of cognitive reserve (premorbid IQ and years of education) in TBI and non-TBI cohorts. Method: Participants were 105 individuals with moderate-severe TBI (10-33 years post injury) and 91 participants without TBI. Cognitive outcome was examined across four cognitive factors; verbal memory, visual ability and memory, executive attention, and episodic memory. Functional outcome was measured using the Glasgow Outcome Scale Extended. The CRIq total score and three subscale scores (education, work, leisure) were examined. Results: In the TBI cohort, associations were identified between two CRIq subscales and cognitive factors (CRIq education and verbal memory; CRIq work and executive attention). There were no associations between CRIq leisure and cognitive outcomes, or between CRIq and functional outcome. Model selection statistics suggested premorbid IQ and years of education provided a better fit than the CRIq for the relationship between cognitive reserve with two cognitive factors and functional outcome, with neither model providing an improved fit for the remaining two cognitive factors. This finding was broadly consistent in the non-TBI cohort. Conclusion: Cognitive reserve contributes significantly to long-term clinical outcomes following moderate-severe TBI. The relationship between cognitive reserve and long-term cognitive and functional outcomes following TBI is best characterised with traditional proxies of cognitive reserve, mainly premorbid IQ, rather than the CRIq.

Tipping the Balance Between Cognitive Reserve, Frailty, and Dementia in the Very Old?

Background

As the population ages, the concept of frailty becomes increasingly relevant and may be considered a precursor between aging and the development of dementia in later life. Similarly, the construct of cognitive reserve (CR) is an accepted model of cognitive resilience that may account for individual differences in trajectories of brain aging, mitigating the clinical expression of dementia.

Objective

We aim to estimate the role of CR and frailty in moderating the prediction of dementia in the population aged over 80 who are attending an Italian outpatient memory clinic.

Methods

Comprehensive Geriatric Assessment, Clinical Frailty Scale (CFS) to screen for frailty, and Cognitive Reserve Index questionnaire (CRIq) to evaluate CR, were used to assess patients systematically. We performed multivariate logistic regression to assess associations with dementia. Model performance and interaction between frailty and cognitive reserve were then evaluated.

Results

166 patients were consecutively enrolled (mean age was 85.7 years old, females composed 68%); 25% had a diagnosis of amnestic mild cognitive impairment, and 75% had a diagnosis of dementia. Multivariate regression analysis showed that CRIq and CFS were the main clinical assessment tools associated with the presence of dementia, even after collinearity adjustment. No significant interaction of CFS*CRIq was found.

Conclusions

To our knowledge, this is the first study to investigate the association between CR, frailty, dementia, and their related interacting terms in a real-world population of very old patients. Our findings may suggest that both CR and frailty shape an individual's resilience throughout their lifetime. This may potentially counteract the effects of brain neuropathology, in line with the hypothesis that meaningful associations exist between CR, frailty, and cognition in later life.

Measures of cognitive reserve: An umbrella review

Objective: Recently, there has been a growing interest in operationalizing and measuring cognitive reserve (CR) for clinical and research purposes. This umbrella review aims to summarize the existing systematic and meta-analytic reviews about measures of CR. Method: A literature search was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) and the guidelines of Aromataris et al. (2015) to identify the systematic reviews and meta-analysis involving the assessment of CR. The methodological quality of the papers included in this umbrella review was assessed with A Measurement Tool to Assess Systematic Reviews 2 (AMSTAR-2) and Specialist Unit for Review Evidence (SURE). Results: Thirty-one reviews were identified, sixteen of which were systematic reviews, and fifteen were meta-analyses. Most of the reviews had a critically low quality, according to AMSTAR-2. The reviews included between two and 135 studies. Most of the papers focused on older adults, mainly those with dementia. CR was measured using one to six proxies, but most considered each proxy separately. The most assessed proxies of CR were education on its own, combined with occupation and/or engagement in activities or combined with parental education, bilingualism, and engagement in activities when four CR proxies were studied. Most of the studies included in higher quality reviews focused on three proxies, with education and engagement in activities being the most evaluated using CR questionnaires. Conclusion: Despite the growing interest in measuring CR, its operationalization did not improve since the last umbrella review in this field.

Validation of the Cognitive Reserve Index Questionnaire (CRIq) in Arabic

Cognitive reserve is the adaptability of cognitive processes in the face of brain aging and pathology. This study aimed to validate the Arabic version of the Cognitive Reserve Index Questionnaire (CRIq) in a healthy Lebanese sample. CRIq assesses cognitive reserve through three domains: education, working activity, and leisure time. Statistical measures, including descriptive and regression analysis along with structural equation modeling, were utilized to investigate the convergent and discriminant validity of the CRIq, incorporating fluid intelligence (Gf) and measures of cognitive function, long-term memory encoding and retrieval (Glr), and processing speed (Gs). Results from 174 participants revealed that the activities assessed by the CRIq-Arabic were comparable to the original CRIq study, with slight cultural differences. The internal consistency of the CRIq-Arabic was good (Cronbach's α = 0.88), indicating reliability. Convergent validity was confirmed, with moderate to high loadings on the cognitive reserve latent construct. Discriminant validity was supported as correlations between cognitive reserve variables and non-target constructs (Gf, Glr, and Gs) were less than 1. The findings provide an initial psychometric validation of the CRIq-Arabic. Further research of clinical samples is needed to enhance its utility in neuropsychological practice.

s-CRIq: the online short version of the Cognitive Reserve Index Questionnaire

BACKGROUND

The wide use of the term Cognitive Reserve (CR) is in need of a clear and shared definition of its concept and of the development of new tools, quick and easy to use and updated for the people of today. This study describes the online short CRIq (s-CRIq), the new shorter version of the CRIq, following an item analysis revision, and compares the data distribution of different samples.

METHODS

The s-CRIq was administered online to 435 people while another 440 filled out the s-CRIq in self-administration. A further 588 participants had been administered the original paper-and-pencil long CRIq and 344 the online long CRIq.

RESULTS

The major difference in the databases of s-CRIq versus the long versions is an increased score in education and in leisure activity. However, the density distributions of the total score of CRI in the 4 databases share 64% of their areas, and at least two of them share 84%.

CONCLUSION

The s-CRIq proved to be a simple and easy-to-administer tool. Similarly, to the original version, the s-CRIq is freely available on the web, and it is our hope that it will be of fruitful use for researchers and clinicians alike.

Effects of Physical Activity on Cognitive Functioning: The Role of Cognitive Reserve and Active Aging

BACKGROUND

The increase in average life expectancy necessitates the identification of possible mechanisms capable of promoting "active aging" to ensure adequate levels of global functioning. Numerous studies show that regular physical activity promotes, even in the elderly, a state of functional psychophysical well-being capable of slowing down age-related cognitive decline. This study aimed to clarify whether, and how, the intensity of physical activity can modulate cognitive and executive skills by influencing specific psychological variables.

METHODS

Our sample consisted of 151 senior subjects divided into hikers (HIK), gentle gymnastics (GYM), and sedentary (SED), who practice intense, moderate, and reduced physical activity, respectively. A battery of psychological questionnaires was administrated to evaluate attentional skills, decision-making, the ability to implement targeted behaviors, perceived self-efficacy, and psychophysical well-being. We included: the Mini-Mental State Examination, Cognitive Reserve Index Questionnaire, General Self-Efficacy Scale, Letter Cancellation Test, Everyday Competence Questionnaire, and Geriatric Depression Scale (GDS).

RESULTS

Comparisons between the scores reported by the three groups showed that the HIK group differs from the others with respect to most of the measurements, presenting better mood and cognitive performance, and a specific psychological profile. On the contrary, the GYM group appeared to have a greater affinity with the SED group than with the HIK group, both cognitively and psychologically.

CONCLUSIONS

Types of physical activity, as well as the intensity and frequency with which they are practiced, are factors that promote an active aging process, protecting the psychophysical well-being and overall cognitive functioning of the elderly.

Effect of cognitive reserve on the association between slow wave sleep and cognition in community-dwelling older adults

Sleep, especially slow wave sleep (SWS), is essential for cognitive functioning and is reduced in aging. The impact of sleep quality on cognition is variable, especially in aging. Cognitive reserve (CR) may be an important modulator of these effects. We aimed at investigating this question to better identify individuals in whom sleep disturbances might have greater behavioral consequences. Polysomnography and neuropsychological assessments were performed in 135 cognitively intact older adults (mean age ± SD: 69.4 ± 3.8y) from the Age-Well randomized controlled trial (baseline data). Two measures of cognitive engagement throughout life were used as CR proxies. Linear regression analyses were performed between the proportion of SWS, and executive function and episodic memory composite scores. Then, interaction analyses between SWS and CR proxies on cognition were conducted to assess the possible impact of CR on these links. SWS was positively associated with episodic memory, but not with executive function. CR proxies modulated the associations between SWS and both executive and episodic memory performance. Specifically, individuals with higher CR were able to maintain cognitive performance despite low amounts of SWS. This study provides the first evidence that CR may protect against the deleterious effects of age-related sleep changes on cognition.

Cognitive reserve counteracts typical neural activity changes related to ageing

Studies have shown that older adults with high Cognitive Reserve (HCR) exhibit better executive functioning than their low CR (LCR) counterparts. However, the neural processes linked to those differences are unclear. This study investigates (1) the neural processes underlying executive functions in older adults with HCR compared to older adults with LCR and (2) how executive control differences between HCR and LCR groups are modulated by increased task difficulty. We recruited 74 participants (37 in each group) with diverse CR levels, as determined by a standardised CR questionnaire. Participants performed two executive control tasks with lower and higher difficulty levels (i.e., Simon and spatial Stroop tasks, respectively) while recording the electroencephalogram. The accuracy on both tasks requiring inhibition of irrelevant information was better in the HCR than the LCR group. Also, in the task with higher difficulty level (i.e., the spatial Stroop task), event-related potential (ERP) latencies associated with inhibition (i.e., frontal N200) and updating of working memory (i.e., P300) were earlier in HCR than LCR. Moreover, the HCR, but not the LCR group, showed larger P300 amplitude in parietal than frontal regions and in the left than right hemisphere, suggesting a posterior to anterior shift of activity and loss of inter-hemispheric asymmetries in LCR participants. These results suggest that high CR counteracts neural activity changes related to ageing. Thus, high levels of CR may be related to maintenance of neural activity patterns typically observed in young adults rather than to deployment of neural compensatory mechanisms.

Systematic examination of methodological inconsistency in operationalizing cognitive reserve and its impact on identifying predictors of late-life cognition

BACKGROUND

Cognitive reserve (CR) is the ability to maintain cognitive performance despite brain pathology. CR is built through lifecourse experiences (e.g., education) and is a key construct in promoting healthy aging. However, the operationalization of CR and its estimated association with late-life cognition varies. The purpose of this study was to systematically examine the operationalization of CR and the relationship between its operationalization and late-life cognition.

METHODS

We performed a comprehensive review of experiences (proxies) used to operationalize CR. The review informed quantitative analyses using data from 1366 participants of the Memory and Aging Project to examine 1) relationships between proxies and 2) the relationship between operationalization and late-life cognition. We also conducted a factor analysis with all identified CR experiences to create a composite lifecourse CR score. Generalized linear mixed models examined the relationship between operationalizations and global cognition, with secondary outcomes of five domains of cognition to examine consistency.

RESULTS

Based on a review of 753 articles, we found the majority (92.3%) of the 28 commonly used proxies have weak to no correlation between one another. There was substantial variability in the association between operationalizations and late-life global cognition (median effect size: 0.99, IQR: 0.34 to 1.39). There was not strong consistency in the association between CR operationalizations and the five cognitive domains (mean consistency: 56.1%). The average estimate for the 28 operationalizations was 0.91 (SE = 0.48), compared to 2.48 (SE = 0.40) for the lifecourse score and it was associated with all five domains of cognition.

CONCLUSIONS

Inconsistent methodology is theorized as a major limitation of CR research and barrier to identification of impactful experiences for healthy cognitive aging. Based on the weak associations, it is not surprising that the relationship between CR and late-life cognition is dependent on the experience used to operationalize CR. Scores using multiple experiences across the lifecourse may help overcome such limitations. Adherence to a lifecourse approach and collaborative movement towards a consensus operationalization of CR are imperative shifts in the study of CR that can better inform research on risk factors related to cognitive decline and ultimately aid in the promotion of healthy aging.

Openness to experience and cognitive functioning and decline in older adults: The mediating role of cognitive reserve

OBJECTIVE

Openness to experience has been consistently associated with better cognitive functioning in older people, but its association with cognitive decline is less clear. Cognitive reserve has been proposed as a mechanism underlying this relationship, but previous studies have reported mixed findings, possibly due to the different ways of conceptualizing cognitive reserve. We aimed to analyze the potential mediating role of cognitive reserve in the association between openness and cognitive functioning and decline in healthy older people.

METHOD

In Wave 1 and at the four-year follow-up (Wave 2), 87 healthy older people (49.4% women; M age = 65.08, SD = 4.54) completed a neuropsychological battery to assess cognitive functioning and a questionnaire to assess cognitive reserve. Openness was measured with the NEO- Five-Factor Inventory. Mediation models were proposed to investigate the relationship between openness and cognitive function or decline through cognitive reserve or its change.

RESULTS

Cognitive reserve mediated the openness-cognitive functioning association. Thus, individuals with higher openness showed greater cognitive reserve, and this greater cognitive reserve was associated with better cognitive functioning. Moreover, greater cognitive reserve at baseline also mediated the association between higher openness and slower cognitive decline. However, change in cognitive reserve did not mediate the association between openness and change in cognitive functioning.

CONCLUSIONS

Cognitive reserve is a mechanism underlying the association between openness and cognitive functioning and decline. These findings support the differential preservation hypothesis, suggesting that healthy older adults who engage in more cognitively stimulating activities would show less age-related cognitive decline.

The indirect effect of cognitive reserve on the relationship between age and cognition in pathological ageing: A cross-sectional retrospective study in an unselected and consecutively enrolled sample

Cognitive reserve (CR) allows individuals to maintain cognitive functionality even in the presence of pathologies. The compensation hypothesis suggests that CR plays an indirect role between age and cognitive decline, contrasting the negative effect of ageing on cognition. We test this hypothesis in an unselected and consecutively enrolled sample of memory clinic attendees (n = 134) who completed the CR Index questionnaire and three neuropsychological tests assessing global cognition (MMSE, FAB, CDT). Participants were divided into two groups based on standard diagnostic criteria (DSM-5): those who were cognitively impaired (n = 92) and those who were preserved (n = 42). A principal component analysis was used to extract a composite measure of global cognitive functioning from the three neuropsychological tests, and mediation analysis was used to examine the relationship between CR, age and global cognitive functioning in the two groups. Results revealed that: (i) age had a significant direct negative effect on the global cognitive score in both groups; (ii) the three socio-behavioural proxies of CR together suppress the direct negative relationship between age and global cognitive score in cognitively impaired patients but not in cognitively preserved participants. This study confirms the association between CR, age and cognition and allows us to validate its role in a population with cognitive impairment and extend findings to a low-to-middle educated population. These results hold important implications for public health and wellness promotion, emphasising the beneficial role of maintaining healthy and active physical, cognitive and social lifestyles.

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.

Internal consistency and reliability of the lifetime and modified current cognitive activity questionnaires and their association with cognitive performance: a six-year follow up of the Brain in Motion study

INTRODUCTION

Cognitive activity questionnaires could provide insight into neurocognitive reserve. The Lifetime Cognitive Activities Questionnaire (LCAQ) assesses cognitive activities at four stages of life. The Modified Current Cognitive Activities Questionnaire (CCAQ) assesses current cognitive activities. We examined the construct validity, internal consistency, test-retest reliability, and stability of these questionnaires throughout the Brain in Motion (BIM) study and their relationship with cognitive performance.

METHODS

The LCAQ, Montreal Cognitive Assessment (MoCA), and neuropsychological battery were administered at the initial pre-intervention and six-year follow-up. The CCAQ was administered at five timepoints. Construct validity of the CCAQ/LCAQ was assessed using proxies of cognitive engagement (educational attainment and the North American Adult Reading Test [NAART]). Cronbach alpha analysis determined internal consistency. LCAQ reliability was established by comparing the pre-intervention and six-year follow-up. CCAQ reliability was determined by comparing both pre-intervention assessments, correlations throughout BIM determined stability. A multiple linear regression investigated the associations between cognitive engagement and cognitive domains derived from a principal component analysis.

RESULTS

MoCA scores at the initial pre-intervention (27.49 ± 1.46) and six-year follow up (26.53 ± 2.08). The LCAQ and CCAQ correlated with educational attainment and the NAART. The LCAQ (n = 266) produced an alpha of 0.90 (20 items). The CCAQ (n = 261) resulted in an alpha of 0.71 (25 items). LCAQ scores (n = 94) at the initial pre-intervention and six-year follow-up were correlated. CCAQ (n = 94) scores at the initial pre-intervention correlated with scores at all five other timepoints. The multiple linear regression revealed associations between the CCAQ and verbal memory/attention. The NAART was associated with processing speed, concept formation, and verbal memory/attention.

CONCLUSIONS

In the absence of cognitive decline, these questionnaires exhibit significant construct validity, internal consistency, test-retest reliability, and the CCAQ displayed stability. The NAART and CCAQ were associated with neuropsychological performance. Our findings support future use of these questionnaires and exemplify the neuroprotective role of cognitive engagement.

Cognitive reserve as a moderator of outcomes in five clusters of first episode psychosis patients: a 10-year follow-up study of the PAFIP cohort

BACKGROUND

Cognitive reserve (CR) has been associated with the development and prognosis of psychosis. Different proxies have been used to estimate CR among individuals. A composite score of these proxies could elucidate the role of CR at illness onset on the variability of clinical and neurocognitive outcomes.

METHODS

Premorbid intelligence quotient (IQ), years of education and premorbid adjustment were explored as proxies of CR in a large sample (N = 424) of first-episode psychosis (FEP) non-affective patients. Clusters of patients were identified and compared based on premorbid, clinical and neurocognitive variables at baseline. Additionally, the clusters were compared at 3-year (N = 362) and 10-year (N = 150) follow-ups.

RESULTS

The FEP patients were grouped into five CR clusters: C1 (low premorbid IQ, low education and poor premorbid) 14%; C2 (low premorbid IQ, low education and good premorbid adjustment) 29%; C3 (normal premorbid IQ, low education and poor premorbid adjustment) 17%; C4 (normal premorbid IQ, medium education and good premorbid adjustment) 25%; and C5 (normal premorbid IQ, higher education and good premorbid adjustment) 15%. In general, positive and negative symptoms were more severe in the FEP patients with the lowest CR at baseline and follow-up assessments, while those with high CR presented and maintained higher levels of cognitive functioning.

CONCLUSIONS

CR could be considered a key factor at illness onset and a moderator of outcomes in FEP patients. A high CR could function as a protective factor against cognitive impairment and severe symptomatology. Clinical interventions focused on increasing CR and documenting long-term benefits are interesting and desirable.

Big Five personality factors predict self-rated cognitive reserve: a two-wave online study in a Mexican sample

Introduction: One of the main contributors to cognitive reserve (CR) is the involvement in cognitively stimulating activities (CSAs), including education, work, leisure, social and physical activities. Personality traits are plausible determinants of CR, influencing the tendency to engage in CSAs. The goal of this study was to evaluate the association between personality and CR, operationalised as self-rated involvement in CSAs, in a sample of individuals aged 18-50 or more. Method: We collected two-wave non-probabilistic online data throughout Mexico. The instruments were the Big Five Inventory-2 for the baseline, its extra-short form for the follow-up and the Self-Rating of Cognitive Reserve (SRCR). Confirmatory factor analyses (CFAs) were performed to test the unifactorial structure of the SRCR, and multiple regressions were conducted with personality factors as predictors of CR. Results: For the baseline, 2025 participants were recruited, and 610 for the follow-up, most of them female and aged 18-40. CFAs showed excellent goodness-of-fit, and the regression analyses proved Negative Emotionality and Extraversion to be the main predictors of CR. Conclusions: Our study highlights the need to identify personality profiles at high risk of underdevelopment of CR in ages where it is still feasible to promote engagement in CSAs.

It's never too late to improvise: The impact of theatre improvisation on elderly population

Despite the availability of improvisational theater training in different settings, studies that assess its effectiveness as a means for enhancing cognitive training for older adults are scarce. This study examines the influence of short theater improvisation exercises on the cognitive flexibility of cognitively-healthy older adults, and their influence on the four core components of improvisation (i.e., spontaneity, flow, creativity, playfulness). The study also examines the correlation between an improvement in these four key agents and an improvement in cognitive flexibility among older adults. This quantitative empirical study was conducted in retirement homes and daycare centers in Israel. A total of 45 participants took part in this study, all in good physical health and with age-appropriate cognitive abilities. The participants were divided into five research groups; each group met twice a week for a one-hour improvisation session over a six-week period. The data was collected through five questionnaires that were completed at four points of time (before, during, and after the workshop). The findings did not indicate a significant effect of the improvisation exercises on the participants' cognitive flexibility, yet they did show improvement in three components of improvisation: spontaneity, flow, playfulness. As such, the findings of this study indicate that despite a normal decline in basic cognitive functioning among older adults, the beneficial effect of improvisation on cognitive flexibility might still occur through spontaneity, playfulness, and flow. In conclusion, short theater improvisation exercises could contribute to various indicators of healthy aging in various settings.

Mediation effects of cognitive, physical, and motivational reserves on cognitive performance in older people

Introduction

We study from a multidimensional perspective the different factors that help prevent the development of cognitive impairment in old aging.

Methods

This study analyzed in 300 elderly subjects the relationship between cognitive reserve (CR), physical reserve (PR) and motivational reserve (MR) with cognitive impairment. This study also takes into consideration different variables (sex, age, educational level, and institutionalization) that might affect the results in the different types of reserves (CR, physical and MR) and cognitive impairment.

Results

The results show that people with a higher cognitive reserve, physical reserve and motivational reserve have less cognitive impairment.

Discussion

Therefore, it is important to consider measuring the CR as a variable to diagnose neurodegenerative illnesses but it is also essential to consider the physical state and physical activity, as well as the motivational dimension. With the cognitive reserve and sex variables no significant differences were observed. Age had a negative effect on strategic flexibility, but those with higher CR had better cognitive flexibility and the educational.

Protocol for a pre-post, mixed-methods feasibility study of the Brain Bootcamp behaviour change intervention to promote healthy brain ageing in older adults

INTRODUCTION

Behaviour change interventions represent key means for supporting healthy ageing and reducing dementia risk yet brief, scalable behaviour change interventions targeting dementia risk reduction in older adults is currently lacking. Here we describe the aims and design of the three-month Brain Bootcamp initiative that seeks to target multiple dementia risk and protective factors (healthy eating, physical, social and cognitive inactivity), through the use of multiple behaviour change techniques, including goal-setting for behaviour, information about health consequences and physical prompts to change behaviours that reduce dementia risk among older adults. Our secondary aim is to understand participants' views of dementia prevention and explore the acceptability and integration of this campaign into daily life.

METHODS

Brain Bootcamp is a pre-post feasibility trial conducted in Sydney, Australia beginning in January 2021 until late August. Participants aged ≥65 years living independently in the community (n = 252), recruited through social media and flyers, will provide information about their demographics, medical history, alcohol consumption, smoking habits, mental health, physical activity, cognitive activity, and diet to generate a dementia risk profile at baseline and assess change therein at three-month follow-up. During the intervention, participants will receive a resource pack containing their individual risk profile, educational booklet on dementia risk factors and four physical items designed to prompt physical, social and mental activity, and better nutrition. Outcome measures include change in dementia risk scores, dementia awareness and motivation. A qualitative process evaluation will interview a sample of participants on the acceptability and feasibility of the intervention.

DISCUSSION

This will be the first short-term multi-domain intervention targeting dementia risk reduction in older adults. Findings will generate a new evidence base on how to best support efforts targeting lifestyle changes and to identify ways to optimise acceptability and effectiveness towards brain health for older adults.

TRIAL REGISTRATION NUMBER

ACTRN 381046 (registered 17/02/2021); Pre-results.

The moderating effect of cognitive reserve on cognitive function in patients with Acute Ischemic Stroke

BACKGROUND

Recovery of cognitive function after stroke has inter-individual variability. The theory of cognitive reserve offers a potential explanation of the variability in cognitive function after stroke.

OBJECTIVE

This study aimed to investigate the moderating effect of cognitive reserve on the relationship between the stroke severity and cognitive function after stroke.

MATERIALS AND METHODS

A total of 220 patients with Acute Ischemic Stroke (AIS) were recruited in 2021 from two stroke centers in Nanjing, China. The National Institutes of Health Stroke Scale (NIHSS) was used to assess stroke severity upon admission. Cognitive Reserve Index questionnaire (CRIq) and validated Montreal Cognitive Assessment, Changsha Version (MoCA-CS) were used to assess cognitive reserve and cognitive function within 7 days after stroke onset, respectively. A series of multivariate linear regression models were applied to test the moderating effect of cognitive reserve.

RESULTS

Patients with a higher level of cognitive reserve had better cognitive function after stroke compared with those with a lower level of cognitive reserve (β = 0.074, p = 0.003). The interaction of NIHSS and cognitive reserve was statistically significant (β = -0.010, p = 0.045) after adjusting for some key covariates [e.g., age, marital status, Oxfordshire Community Stroke Project (OCSP) classification, Trial of ORG 10172 in Acute Stroke Treatment (TOAST) classification, cerebral vascular stenosis, diabetes and atrial fibrillation].

CONCLUSION

Cognitive reserve may help to buffer the effect of stroke-related pathology on cognitive decline in Chinese acute stroke patients. Enhancing cognitive reserve in stroke patients may be one of the potential strategies for preventing vascular dementia.

The relationship between cognitive reserve and cognition in healthy adults: a systematic review

The concept of Cognitive Reserve (CR) refers to the individual differences allowing some people to cope better with brain pathology. The aim of the present review was to explore the relationship between CR and cognition in adulthood. This association has been addressed in several neuro(psycho)logical disorders and in healthy elderly people. However, few studies explored this issue in adulthood (age range 18–65), when individuals might take advantage the most from psychoeducational approaches aimed at increasing CR. For our systematic review, we selected studies assessing CR and adopting neuropsychological and experimental tasks for evaluation of cognitive functioning in healthy individuals. In the selected articles, we examined the relationship of singular proxies, composite indexes or standardized scales of CR with measures of general cognition, attention, inhibitory control, verbal fluency, constructional abilities, and verbal and spatial memory. The results suggested a positive relationship between singular CR proxies, composite indexes or standardized scales, and almost all the explored cognitive domains. No clear conclusion could be made on constructional abilities due to the scarcity of available studies. CR seems associated with better cognitive performance in adulthood, but definite methodological improvements and the use of standardized scales for CR are necessary to reduce inconsistencies among studies.

The Chinese Translation Study of the Cognitive Reserve Index Questionnaire

Purpose

The purpose of this study was to perform the translation and adaption of the Cognitive Reserve Index questionnaire into Chinese and assess the reliability of the Chinese version.

Materials and Methods

The Chinese version of the Cognitive Reserve Index questionnaire was created from a standard forward-backward translation. A total of 371 volunteers, aged between 20 and 89 years, participated in this survey. Participants were divided into three age-groups (Young, Middle-aged, and Elderly), and subgroup differences were examined by independent samples t-tests, ANOVA analysis as well as post-hoc analysis. Pearson correlation analysis was applied to test the association between the total scores and each subscore (CRI-Education, CRI-WorkingActivity, and CRI-LeisureTime). The internal consistency and test-retest reliability of the Cognitive Reserve Index questionnaire were assessed. The test-retest reliability was measured among 40 participants with a 2-week interval using intraclass correlation coefficient.

Results

Strong correlations were observed between the total scores and each subscore (CRI-Education, CRI-WorkingActivity, and CRI-LeisureTime: r = 0.65, 0.79, and 0.70, respectively). In contrast, it was found low to moderate correlations among three subscores. The internal consistency was acceptable (Cronbach's alpha coefficient = 0.68). The intraclass correlation coefficient for total scores of the Chinese version of the Cognitive Reserve Index questionnaire was 0.87 (95% CI 0.74–0.93).

Conclusion

The Chinese version of the Cognitive Reserve Index questionnaire was a potentially reliable and practical tool for evaluating cognitive reserve accumulated through a person's life span.

Association of cognitive reserve with stroke outcome: a protocol for a systematic review

INTRODUCTION

The concept of cognitive reserve (CR) was introduced to account for individual differences in the clinical manifestation of neurodegenerative diseases. Though several mechanisms and risk factors are shared between neurodegeneration and stroke, the effect of CR on poststroke functional outcome has been poorly addressed. This systematic review aims to synthesise the available research evidence on the association of CR with stroke outcome, in order to implement the understanding of interindividual variability in stroke outcome and to improve its prediction.

METHODS AND ANALYSIS

Cochrane Library, Embase, PubMed, Web of Science and reference lists of relevant literature will be searched for publications on CR proxies (eg, education, years of education, occupational attainment, premorbid intelligence) and stroke outcome, published between 1 January 1980 and 10 March 2022. Two reviewers will independently perform the study selection, data extraction and quality assessment. Disagreements between reviewers will be resolved by a third independent reviewer. The Quality In Prognosis Studies tool will be used to assess the quality of each included study. The primary outcome will be functional outcome after stroke assessed with modified Rankin Scale, activities of daily living (eg, Barthel Index), National Institute of Health Stroke Scale, dichotomised as favourable versus not favourable as well as reported as continuous or ordinal variables. Qualitative and quantitative findings will be summarised and, if possible, data will be synthesised using appropriate meta-analytical methods. The quality of evidence will be assessed using the Grading of Recommendations Assessment, Development and Evaluation framework.

ETHICS AND DISSEMINATION

No ethical approval is required as it is a protocol for a systematic review and the data used will be extracted from published studies. The findings from this systematic review will be disseminated in a peer-reviewed scientific journal and presented at conferences. The data will be made freely available.

PROSPERO REGISTRATION NUMBER

CRD42021256175.

The Nuance of Bilingualism as a Reserve Contributor: Conveying Research to the Broader Neuroscience Community

The neurological notion of "reserve" arises from an individually observable dissociation between brain health and cognitive status. According to the cognitive reserve hypothesis, high-reserve individuals experience functional compensation for neural atrophy and, thus, are able to maintain relatively stable cognitive functioning with no or smaller-than-expected impairment. Several lifestyle factors such as regular physical exercise, adequate and balanced nutrition, and educational attainment have been widely reported to contribute to reserve and, thus, lead to more successful trajectories of cognitive aging (CA). In recent years, it has become clear that bilingualism is also a potential reserve contributor. Yet, there is little communication between the neuroscience of bilingualism research community and researchers working in the field of CA more generally, despite compelling reasons for it. In fact, bilingualism tends to be overlooked as a contributory factor in the CA literature, or reduced to a dichotomous trait, despite it being a complex experience. Herein, we discuss issues that are preventing recognition of bilingualism as a reserve contributor across all literatures, highlight the benefits of including language experiences as a factor of interest across research disciplines, and suggest a roadmap to better integrate bilingualism and aging moving forward. We close with calls toward a model of aging that examines the contributions across lifestyle factors, including that of bilingual experience.

Cognitive reserve and coping strategies predict the level of perceived stress during COVID-19 pandemic: A cross-sectional study

The COVID-19 pandemic and the measures to avert contagion heavily impacted individuals' mental health. In the present cross-sectional study, we investigate the relationship between cognitive reserve, coping modalities and the perceived stress during a chronic stage of COVID-19 pandemic by online administration of three standardized questionnaires in a sample of healthy volunteers covering a large lifespan (18–85 years). We found that positive orientation to problems and higher levels of cognitive reserve were associated with lower levels of stress. Conversely, coping strategies involving negation, substance consumption, and appeal to other people and religion to face everyday life, together with higher education, were associated with higher levels of stress. These results shade light on the long-term psychological consequences of COVID-19 and call for the development of psychological interventions improving coping and cognitive reserve, to preserve and restore mental health following the pandemic.