Review
Efficiency, capacity, compensation, maintenance, plasticity: emerging concepts in cognitive reserve

https://doi.org/10.1016/j.tics.2013.08.012Get rights and content

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.

Cognitive reserve (CR) is a concept meant to account for the frequent discrepancy between an individual's measured level of brain pathology and her expected cognitive performance. It is particularly important within the context of aging and dementia, but has wider applicability to all forms of brain damage. As such, it has intimate links to related compensatory and neuroprotective concepts, as well as to the related notion of brain reserve. In this article, we introduce the concept of cognitive reserve and explicate its potential cognitive and neural implementation. We conclude that cognitive reserve is compatible and complementary with many related concepts, but that each much draw sharper conceptual boundaries in order to truly explain preserved cognitive function in the face of aging or brain damage.

Section snippets

The reserve concept

CR (see Glossary) has been proposed to account for the frequent discrepancy between a person's underlying level of brain pathology (or age-related changes) and the observed functional and/or cognitive deficits that are expected to result from that pathology 1, 2. There is extensive epidemiological and experimental evidence for the existence of such reserve: life exposures, such as educational and occupational attainment, and engagement in leisure and social activities have each been associated

Models of reserve

Below we outline some of the dominant theories of preserved cognitive function in the face of advanced age, dementia, and/or brain damage. These theories focus either on compensatory mechanisms (emphasizing adaptations to diminished function or impaired brain structure), neuroprotective mechanisms (emphasizing factors which prevent diminished function and impaired structure), or some combination of both. The main models we discuss are BR, CR, BM, and neurocognitive scaffolding.

Concluding remarks

In this review, we attempted to clarify some of the conceptual relationships between CR and closely related models. As imaging methods become more advanced and macrostructural changes reveal their microstructural correlates, BR and CR may grow more interconnected. Much more fine-grained brain measures are necessary than the standard proxies for BR, such as brain size, and CR can point towards which of these more subtle measures are relevant. BM theories, meanwhile, are complementary to CR, but

Acknowledgements

Supported by NIH/NIA RO1 AG26158.

Glossary

Brain reserve (BR)
differences in brain size and other quantitative aspects of the brain that explain differential susceptibility to functional impairment in the presence of pathology or other neurological insult.
Cognitive reserve (CR)
differences in cognitive processes as a function of lifetime intellectual activities and other environmental factors that explain differential susceptibility to functional impairment in the presence of pathology or other neurological insult.
Neural reserve
one

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