Alzheimer's disease (AD) is the most common form of dementia, accounting for as much as 70% of all cases of dementia. The earliest symptom in most patients is progressive difficulty learning and retaining new information. With progression of the disease, symptoms of poor judgment, disorientation, word finding problems and difficulties with spatial relationships develop. Eventually AD affects almost all aspects of brain functioning, including personality, and the ability to perform the most basic activities of daily functioning.
Patients with progressive memory loss should be evaluated to rule out possible treatable causes of memory loss, such as thyroid disease or vitamin deficiencies. Brain imaging and detailed examination of cognitive functions through a neuropsychological examination may be required to establish a diagnosis of AD. If a diagnosis of AD is confirmed, there are now several medications available that have been shown to ameliorate the symptoms of the disease.
Age is one of the most important risk factors for AD; the number of patients with AD doubles every 5 years beyond age 65. The underlying cause of the symptoms is the gradual loss of nerve cells in the brain, as a result of the accumulation of abnormal structures called amyloid plaques and neurofibrillary tangles.