Alois Alzheimer and vascular brain disease: Arteriosclerotic atrophy of the brain

Epidemiology of Vascular Dementia

The notion of what qualifies as vascular dementia has varied greatly since the first mention of dementia after apoplexy in ancient literature. Current insight points towards a multifactorial cause of cognitive decline at old age, in which vascular components like atherosclerosis, arterio(lo)sclerosis, (micro)infarcts, and amyloid angiopathy play an important role alongside other markers of neurodegeneration. Cerebrovascular disease will be present in most individuals with dementia, but-just like other causes-rarely a cause on its own. The consequent limitations of nosology may be alleviated by addition of a vascular component to the recently introduced amyloid/tau/neurodegeneration etiological classification system for dementia. Meanwhile, risk of dementia is increased about 2-fold after stroke, and the prevention of (recurrent) stroke remains a cornerstone in the prevention of vascular dementia. Similarly, control of cardiovascular risk factors from middle age onwards is likely to have contributed to the reported decline in the age-specific incidence of dementia over the past decades. In conjunction with experimental studies, large-scale observational evidence from imaging, genomics, metabolomics, and alike will continue to improve our understanding of the underlying pathophysiological processes. To prevent ecological fallacies, such etiological studies in patients with dementia are best served by inclusion of subjects regardless of the presumed (single) cause of their disease.

Alzheimer and vascular brain diseases: Focal and diffuse subforms

Alois Alzheimer is best known for his description of the pre-senile neurodegenerative disease named after him. However, his previous interest in vascular brain diseases, underlying cognitive and behavioral changes, was very strong. Besides describing the Arteriosclerotic atrophy of the brain and the arteriosclerotic subtype of Senile dementia which he viewed as main forms of vascular brain diseases, he also identified and described a series of conditions he considered subforms. These may be divided, as suggested by the authors of the present paper, into 3 groups: gliosis and sclerosis, subcortical atrophies, and apoplectic. The subforms of the three groups present characteristic neuropathological features and clinical, cognitive and behavioral manifestations. These provide the basis, together with part of the main forms, for the contemporary condition known as Vascular Cognitive Impairment.

Alzheimer and vascular brain disease: Senile dementia

Alois Alzheimer is best known for his description of a novel disease, subsequently named after him. However, his wide range of interests also included vascular brain diseases. He described Senile dementia, a highly heterogeneous condition, and was able not only to distinguish it from syphilitic brain disease, but also to discriminate two clinicopathological subtypes, that may be labeled a "arteriosclerotic subtype", comparable to the present clinicopathological continuum of "Vascular cognitive impairment", and another as a "neurodegenerative subtype", characterized by primary [cortical] ganglion cell [nerve cells] degeneration, possibly foreshadowing a peculiar presenile disease that he was to describe some years later and would carry his name. He also considered the possibility of a senile presentation of this disease subtype, which was described by Oskar Fischer a short time later. Considering the clinicopathological overlapping features of the "arteriosclerotic subtype" of Senile dementia with Arteriosclerotic atrophy of the brain, it might be possible to consider that both represent a single condition.