Alzheimer's disease is a progressive, irreversible, incurable, neurodegenerative illness and the most common of the dementing disorders. It starts usually after 60 years of age and may span 8 to 12 years.
The continuous and slow decline caused by this disease, is characterized by cognitive deterioration, loss of functional independence, changes in behaviour, and expanding needs for care. In the last three decades, the proteins predominating neuritic plaques and neurofibrillary tangles have been detected and researched: amyloid-beta protein in the plaques and hyperphosphorylated tau in the tangles.
Alzheimer's disease is now considered a long-term process with a slow progress and with a prolonged development of pathological changes that precedes symptoms by years. AD is becoming one of the most problematic and expensive illness for the civilization, also known as "silent threat".