Highlights • We examine cognitive reserve and related concepts (brain reserve/maintenance, cognitive flexibility, scaffolding). • These concepts are complementary rather than competing. • Cognitive ...and brain reserve influence one another and are interconnected. • Cognitive reserve is compatible with neuroprotective theories, such as brain maintenance. • To be truly useful, all models must identify underlying neural and cognitive mechanisms.
Background and aims: The concept of “reserve” has been used to explain the difference between individuals in their capacity to cope with or compensate for pathology. Brain reserve refers to ...structural aspects of the brain, such as brain size and synapse count. Cognitive reserve is the ability to optimize and maximize performance through two mechanisms: recruitment of brain networks, and/or compensation by alternative cognitive strategies. The aim of the present research was to devise an instrument for comprehensive assessment and measurement of the quantity of cognitive reserve accumulated by individuals throughout their lifespan. Methods: A new approach using the Cognitive Reserve Index questionnaire (CRIq) was developed and tested in a sample of 588 healthy individuals, from 18 to 102 years old, stratified by age (Young, Adults, Elderly) and gender. The CRIq includes demographic data and items grouped into three sections: education, working activity and leisure time, each of which returns a subscore. The WAIS Vocabulary test and TIB were also administered. Results: The main descriptive features and some inferential results are described. Intelligence was only moderately correlated with cognitive reserve, stressing the distinction between these two concepts. Age and gender significantly affected CRIq scores, whereas no effect emerged from their interaction. Adults showed a higher score than Young and Elderly. Conclusions: This study provides a new instrument for a standardized measure of the cognitive reserve accumulated by individuals through their lifespan. The potential use of the CRIq in both experimental research and clinical practice is discussed.
We examined if baseline levels of cognitive reserve (CR) and of Alzheimer's disease (AD) biomarkers modify the rate of change in cognition among individuals with normal cognition at baseline (n = ...303, mean baseline age = 57 years, mean follow-up = 12 years); 66 participants subsequently developed mild cognitive impairment (MCI) or dementia due to AD. CR was indexed by years of education, reading, and vocabulary measures. AD biomarkers were measured with a composite score composed of measures of amyloid, phosphorylated tau, and neurodegeneration. Higher CR scores were associated with better cognitive performance but did not modify the rate of change in cognition among those who remained cognitively normal, nor among those who progressed to MCI before symptom onset, independent of baseline biomarker levels. However, higher CR scores were associated with faster cognitive decline after symptom onset of MCI. These results suggest that the mechanism by which CR mediates the relationship between pathology and cognitive function is by delaying the onset of symptoms rather than reducing the rate of cognitive decline.
We discuss the role of bilingualism as a source of cognitive reserve and we propose the putative neural mechanisms through which lifelong bilingualism leads to a neural reserve that delays the onset ...of dementia.
Recent findings highlight that the use of more than one language affects the human brain in terms of anatomo-structural changes. It is noteworthy that recent evidence from different places and cultures throughout the world points to a significant delay of dementia onset in bilingual/multilingual individuals. This delay has been reported not only for Alzheimer's dementia and its prodromal mild cognitive impairment phase, but also for other dementias such as vascular and fronto-temporal dementia, and was found to be independent of literacy, education and immigrant status.
Lifelong bilingualism represents a powerful cognitive reserve delaying the onset of dementia by approximately 4 years. As to the causal mechanism, because speaking more than one language heavily relies upon executive control and attention, brain systems handling these functions are more developed in bilinguals resulting in increases of gray and white matter densities that may help protect from dementia onset. These neurocognitive benefits are even more prominent when second language proficiency and exposure are kept high throughout life.
We investigated the contribution of bilingual experience to the development of cognitive reserve (CR) when compared with other, traditionally more researched, CR proxies, in a sample of cognitively ...healthy senior (60 +) bilingual speakers. Participants performed in an online study where, in addition to a wide inventory of factors known to promote CR, we assessed several factors related to their second language (L2) use. In addition, participants' inhibitory executive control was measured via the Flanker Task. We used Structural Equation Modeling to derive a latent composite measure of CR informed by traditional CR proxies (i.e., occupational complexity, marital status, current and retrospective socio-economic status, physical exercise, perceived positive support, maximal educational attainment, frequency of leisure activities and extent of social network). We examined whether bilingualism may act as a mediator of the effects of such proxies on cognitive performance therefore assessing the unique contribution of dual language use to CR. First, our analyses revealed facilitatory effects of both L2 age of acquisition and L2 proficiency on the executive performance. Second, our analyses confirmed the moderating role of bilingual experience on the relationship between other factors known to promote CR and cognitive integrity, revealing a strong contribution by bilingualism to CR development. Our findings provide further support to the notion that bilingualism plays an important role in mitigating cognitive decline and promoting successful aging.
Level of education is often regarded as a proxy for cognitive reserve in older adults. This implies that brain degeneration has a smaller effect on cognitive decline in those with more education, but ...this has not been directly tested in previous research. We examined how education, quantitative magnetic resonance imaging–based measurement of brain degeneration, and their interaction affect cognitive decline in diverse older adults spanning the spectrum from normal cognition to dementia. Gray matter atrophy was strongly related to cognitive decline. While education was not related to cognitive decline, brain atrophy had a stronger effect on cognitive decline in those with more education. Importantly, high education was associated with slower decline in individuals with lesser atrophy but with faster decline in those with greater atrophy. This moderation effect was observed in Hispanics (who had high heterogeneity of education) but not in African-Americans or Caucasians. These results suggest that education is an indicator of cognitive reserve in individuals with low levels of brain degeneration, but the protective effect of higher education is rapidly depleted as brain degeneration progresses.
Individual differences in cognitive performance increase with advancing age, reflecting marked cognitive changes in some individuals along with little or no change in others. Genetic and lifestyle ...factors are assumed to influence cognitive performance in ageing by affecting the magnitude and extent of age-related brain changes (i.e., brain maintenance or atrophy), as well as the ability to recruit compensatory processes. The purpose of this review is to present findings from the Betula study and other longitudinal studies, with a focus on clarifying the role of key biological and environmental factors assumed to underlie individual differences in brain and cognitive ageing. We discuss the vital importance of sampling, analytic methods, consideration of non-ignorable dropout, and related issues for valid conclusions on factors that influence healthy neurocognitive ageing.
•Higher CR level may ameliorate severity of the symptoms and delays the clinical diagnosis threshold in schizophrenia.•Some evidence claims potential effects of CR on intervention programs, but the ...quality of research could be improved.•Neural plasticity offers an enthusiastic approach to develop targeted interventions programs for people with schizophrenia.
To perform a systematic review of the influence of sociobehavioural indicators of cognitive reserve (CR) in the risk of schizophrenia, the clinical manifestations of the disease, and cognitive intervention programs (CRT) carried out with these patients.
A cross search was made by two independent reviewers in Pubmed and PsycINFO databases using keywords “schizophrenia” and “cognitive reserve.” Twenty-one studies which analyzed different CR proxies were selected and the level of evidence was classified according to the Oxford Centre for Evidence-Based Medicine.
People with higher CR may have a lower risk of developing schizophrenia and a later onset of disease. In addition, they present better neuropsychological and functional performance in the illness course. However, the suspected influence of CR on the effectiveness of CRT in patients with schizophrenia is currently unresolved.
Our findings suggest that higher CR delays the clinical diagnosis threshold and severity of the symptoms in patients with schizophrenia. However, effect of singular sociobehavioral measures on clinical expression and benefits of intervention program need further investigation.
The concept of brain maintenance refers to the preservation of brain integrity in older age, while cognitive reserve refers to the capacity to maintain cognition in the presence of neurodegeneration ...or aging‐related brain changes. While both mechanisms are thought to contribute to individual differences in cognitive function among older adults, there is currently no “gold standard” for measuring these constructs. Using machine‐learning methods, we estimated brain and cognitive age based on deviations from normative aging patterns in the Whitehall II MRI substudy cohort (N = 537, age range = 60.34–82.76), and tested the degree of correspondence between these constructs, as well as their associations with premorbid IQ, education, and lifestyle trajectories. In line with established literature highlighting IQ as a proxy for cognitive reserve, higher premorbid IQ was linked to lower cognitive age independent of brain age. No strong evidence was found for associations between brain or cognitive age and lifestyle trajectories from midlife to late life based on latent class growth analyses. However, post hoc analyses revealed a relationship between cumulative lifestyle measures and brain age independent of cognitive age. In conclusion, we present a novel approach to characterizing brain and cognitive maintenance in aging, which may be useful for future studies seeking to identify factors that contribute to brain preservation and cognitive reserve mechanisms in older age.
Using machine learning, we estimated brain and cognitive age based on deviations from normative aging patterns in the Whitehall II MRI substudy cohort, and tested the degree of correspondence between these constructs, as well as their associations with premorbid IQ, education, and lifestyle trajectories. The study presents a novel approach to characterizing brain and cognitive maintenance in aging, which may be useful for future studies seeking to identify factors that contribute to brain preservation and cognitive reserve in older age.
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