12th Mild Cognitive Impairment Symposium,3rd Early Alzheimers Diagnostic and Treatment Workshop and 2nd Mount Sinai of Floridas Early Alzheimers Public Educational Forum

Current models of Alzheimer's Disease (AD) suggest amyloid deposition is the first in a chain of events which ultimately lead to neurodegeneration and progressive cognitive and functional deterioration. It appears that most of the cognitive effects of Aβ deposition are associated with neurodegeneration, although Aβ itself may cause subtle cognitive impairment, independent of neurodegeneration.

Evidence of Aβ deposition (amyloid positive status) in the brain is present on PET scans or CSF studies among 90 to 95% of individuals with clinically diagnosed Alzheimer's disease, almost all of whom will also have evidence of neurodegeneration, as evidenced by hippocampal atrophy and/or cortical atrophy in AD signature neocortical regions. Among subjects with amnestic MCI only about 50 to 60% are found to be amyloid positive, whereas the frequency of neurodegeneration on MRI scans among aMCI subjects appears to be 80 to 85%.