Existing models fail to account for the complexity and multidimensionality of new data and the growing scientific understanding of neurodegeneration.

With the acceptance that the disease processes leading to dementia begin at least as early as mid-life, there is now a major drive to understand and model this period of ‘disease before dementia’ for a variety of reasons. First, to gather a better understanding of the interplay between disease and risk or resilience factors that have been identified epidemiologically (eg, what is the mechanism by which exercise protects the brain) is necessary. Second, to develop algorithms for use in clinical practice to forecast changes in brain health that may lead to dementia that will underpin the design of tailored risk modification interventions and ‘personalised prevention plans’. And third, with an improved knowledge of the genesis and sequence of neuropathological changes in the predementia phase, there will be an expansion of and assurance in …