Alzheimer's is characterized by a progressive loss of cognitive function over a period of 5 to 15 years that ultimately results in death. At first the symptoms of Alzheimer's express themselves as deficits in memory function. These deficits are often severe enough to interfere with daily living. But outwardly the person may seem normal because their social skills remain intact. Later in the progression of the disease, the person's higher cognitive functions such as abstract reasoning, judgment and language, as well as visuoperceptual abilities and skilled motor movement will become impaired.
Memory deficits continue to worsen as the disease progresses.
A person with Alzheimer's may eventually fail to recognize one's own spouse and children. Affective disturbances such as apathy, depression, agitation, anxiety, progressive paranoia, and delusions are also seen. AD is characterized by the presence of numerous senile plaques and neurofibrillary tangles accompanied by neuronal loss. The extracellular senile plaques are composed of amyloid beta-peptides. The intracellular neurofibrillary tangles are composed of highly phosphorylated tau proteins.