Figure 2.

Basic epidemiology of different types of dementia. Data and p-values from Robinson et al. (2018a). Shown is an elderly cohort (n = 185) with a mean age of 97.7 years in an autopsy study. On the left, we see the prevalence of the cognitive states within this cohort at the time of death. More than half of the people suffered from dementia in this age group, while a quarter suffered from mild cognitive impairment (MCI), and another quarter had no cognitive disturbances. On the right, the clinical diagnosis (ante mortem) for the subpopulation that suffered from dementia is shown. Alzheimer's Disease (AD) is the most prevalent form of dementia; however, mixed forms and other primary neurodegenerative dementias as synucleinopathies or frontotemporal lobar degeneration (FTLD) spectrum also play a role as well as vascular dementia (VD). In the post mortem analysis, the full cohort showed at least partial AD-related pathologic changes: 100% had neurofibrillary tangles of at least Braak stage I, and 63% had neuritic plaques. The mean Braak stage was in the dementia group 4.1, in the non-dementia group 3.2 (p < 0.001). However, the dementia group also showed a significant higher Lewy-body pathology (p = 0.018) and transactive response DNA-binding protein 43 kDa (TDP-43) pathology (p < 0.001) as well as a higher rate of definitive cerebrovascular disease (p = 0.016). These findings indicate that in particular in the “super old,” different neuropathologic changes are probably concomitant and contribute to the development of cognitive decline in dementia—in contrast to the concept of “pure” AD as an isolated neurodegenerative disease.