Alzheimer's disease
Alzheimer's disease (AD), also known as Alzheimer disease, is the most common form of dementia.
There is no cure for the disease, which worsens as it progresses, and eventually leads to death. It was first described by (and later named after) German psychiatrist and neuropathologist Alois Alzheimer in 1906.
Most often, AD is diagnosed in people over 65 years of age, although the less-prevalent early-onset Alzheimer's can occur in much younger people. In 2006, there were 26.6 million people worldwide with AD.
Alzheimer's is predicted to affect 1 in 85 individuals globally by 2050.
Initial symptoms are often mistaken for 'age-related' concerns, or manifestations of stress.
The most common early symptom is short term memory loss—difficulty in remembering recent events.
The diagnosis is usually confirmed with tests that evaluate behaviour and thinking abilities, often followed by a brain scan if available, however, examination of brain tissue is required for a conclusive diagnosis.
As the disease advances, symptoms can include confusion, irritability, aggression, mood swings, trouble with language, and long-term memory loss.
As the person's condition declines they often withdraw from family and society.
Gradually, bodily functions are lost, ultimately leading to death.
Although the speed of progression can vary, the average life expectancy following diagnosis is approximately seven years.
Fewer than 3% of individuals live more than 14 years after diagnosis.
Alzheimer's disease is classified as a neurodegenerative disorder, the cause and progression of which are poorly understood.
The disease process appears to be associated with plaques and tangles in the brain.
No treatments stop or reverse its progression, though some can lessen symptoms.
As of 2014, more than 1,500 clinical trials have been or are being conducted to test various treatments in AD.
Mental stimulation, exercise, and a balanced diethave been suggested as ways to delay cognitive symptoms (though not brain pathology) in healthy older individuals, but there is no conclusive evidence supporting an effect.
Because AD is progressive, the affected person increasingly relies on others for assistance.
The role of the main caregiver is often taken by the spouse or a close relative.
Alzheimer's disease is known for placing a great burden on caregivers; the pressures can be wide-ranging, involving social, psychological, physical, and economic elements of the caregiver's life.
In developed countries, AD is one of the most costly diseases to society.