[Early diagnosis of Alzheimer's disease].

International audienceINTRODUCTION: Diagnosis of Alzheimer's disease (AD) remains difficult to establish, and can only be considered as certain thanks to anatomopathological evidence, or genetic mutations. Current diagnostic criteria rely on innovative imaging and biological tools, in order to detect pathological cues from very early stages, and with best sensibility and sensitivity. STATE OF ART: Advances in neuro-imaging enabled the development of different tools to help establishing the diagnosis, such as cerebral atrophy assessment on magnetic resonance imaging (MRI), and cerebral metabolism study on positron emission tomography (PET). Besides, the increasing use of in vivo biological markers, combined to clinical criteria, enables to discriminate patients from healthy controls at even earlier stages. This includes studies on tau and beta-amyloid proteins concentrations in the cerebrosinal fluid, and amyloid-specific radioligands uptake. Familial forms of Alzheimer represent a great model for studying early or even pre-symptomatic AD, as genetic analyses constitute a diagnosis of certainty, even though they usually evolve earlier and faster. PERSPECTIVES, CONCLUSION: Diagnostic tools are more and more numerous and performant. According to patients' clinical heterogeneity, it appears essential to associate different method to investigate, in order to make a diagnosis as early and as reliable as possible