Harnessing brain and cognitive reserve for the prevention of dementia

The concepts of brain and cognitive reserve capture several elements of common wisdom - that we all differ in the neural resources we are endowed at birth, that experience and especially complex mental activities then modify how these neural resources are organized and cultivated, and that after any form of brain injury there is significant individual variation in the degree to which clinical deficits may manifest. Transforming these insights into a formal and refutable working definition, however, has been more challenging. Depending on the scale of analysis, brain and cognitive reserve have been defined from neurocentric, neuropsychological, computational, and behavioral perspectives. In our research, we have focused on the behavioral definition, whereby an individual's lifetime exposure to complex mental activities is used for prediction of longitudinal cognitive and neurological change. This approach also benefits from a wealth of epidemiological studies linking heightened complex mental activity with reduced dementia risk. Research in the field of cognitive training is also beginning to indicate that incident cognitive decline can be attenuated, with recent clinical trials addressing the major challenges of transfer of gain and durability of effect. High quality randomized clinical trials are therefore the most urgent priority in this area so that the promise of brain and cognitive reserve can be harnessed for the purpose of the primary prevention of dementia.