Mémoire et imagerie fonctionnelle dans la maladie d'Alzheimer et la variante frontale de la démence fronto-temporale (vf-DFT)

Alzheimer's disease (AD) and frontal variant of fronto-temporal dementia (fv-FTD) represent the two most frequent causes of neuro-degenerative diseases. The mechanisms at the root of memory impairment in AD are principally encoding and consolidation. In fv-FTD, the deficits mainly affect, at least at the beginning of the disease, retrieval processes. The typical pattern of hypometabolism in AD concerns temporo-parietal association cortices, posterior cingulate gyrus and, at a lesser degree, frontal cortex. These functional defects, however, do not fit with the structural abnormalities, which principally affect the hippocampal region. Regarding the fv-FTD patients, the hypometabolic impairments are usually seen in the frontal lobes. Besides, some studies highlight an extension of hypometabolic impairment beyond the frontal lobes. Considering the advances in drug trials, it seems particularly important to benefit from sensitive tools to establish the differential diagnosis between fv-FTD and AD.