Keywords: Alzheimer’s disease, dementia, memory, amyloid, neuropsychology

One of the earliest cerebral changes in patients with Alzheimer’s disease is the accumulation of amyloid plaques. In this thesis, the presence of these plaques was measured in approximately 10,000 test subjects. It was shown that amyloid plaques occurred frequently already in middle-aged, non-demented people, and were also related to subtle memory decline. We calculated that amyloid accumulation can be measured as early as approximately 10 to 15 years prior to the first signs of memory loss and 20 to 30 years prior to the onset of dementia. This knowledge offers opportunities for early treatment. In addition, this thesis substantiates the clinical usefulness of amyloid imaging for the differential diagnosis of dementia and of neuropsychological assessment in people without dementia.