Alzheimeťs disease (AD) is a silent epidemie involving the elderly and is one of most frequent causes of death in the adult population. Probable and possible diagnosis of AD is a clinical one and is based on inter-national eriteria. The definitivě diagnosis of AD is neuropathological. The diagnosis of mild cognitive impairment has a fundamental role in the differential diagnosis of evolving AD. Early form AD concerns the population up to 65 years, latě form AD affects individuals between 65 and 84 years old, and very latě form AD oceurs in the 85+ population. Familiar forms of AD constitute 5-10 % of all cases, whilst sporadic forms account for the remaining 90-95%. The amyloid cascade hypothesis is a fundamental hypothesis for the so-called "Baptists". "Tauists" focus on the metabolism of tau protein. Both hypotheses share some common factors. The pathogenesis of AD involves apoptosis of neurons, inflammatory mechanisms and vascular pathology. Signs and symptoms of AD (e.g. impairment of recent episodic and then of semantic memory, speciál disorientation, altered emotivity, language and executive functions) are in some correlation with the distribution of neuronal tangles and neuritic plaques.

        Key words: Alzheimeťs disease, epidemiology, pathogenesis, brain-behaviour correlation.