Heterogeneity in dementia: challenges and opportunities.

The major sources of heterogeneity in the manifestation of dementia are analyzed as stemming from three types of sources: initial predisposing factors, lifelong events, and the current condition. Each of these sources is, in turn, comprised of three general domains: genetic/biologic/medical, psychosocial, and environmental. These influences affect the manifestation of dementia in terms of cognitive, behavioral, self-maintenance, and affective functioning. Mapping the sources and manifestations of this heterogeneity can lead to both a more thorough understanding of people with dementia and the development of management settings and interventions that are more responsive to people with dementia.