Literature data suggests there are different types of AD depending on their age of onset, called EOAD and LOAD. These two categories are distinguished by the localization of brain atrophy : severe and 'posterior' in EOAD and more 'anterior' in LOAD. Neuro-pathologic data suggests some atypical focal cortical atrophy, characterized by a respect of episodic memory, may be classified within EOAD.
PiB-based PET imaging allows the in-vivo visualization and quantification of amyloïd load.
We want to answer the question whether the amount of amyloïd protein may be lower in LOAD than EOAD in patients showing the same level of dementia, and thus identify ageing-specific cognitive disorders and understand witch factors influence etio-pathology of typical and atypical Alzheimer's disease.