Alzheimer's disease (AD), also known in medical literature as Alzheimer disease, is the most common form of dementia. There is no cure for the disease, which worsens as it  51 , and eventually leads to death. It was first described by German  52  and neuropathologist Alois Alzheimer in 1906 and was named after him. Most often, AD is diagnosed in people over 65 years of age, although the less-prevalent early-onset Alzheimer's can occur much earlier. In 2006, there were 26.6 million sufferers worldwide. Alzheimer's is predicted to  53  1 in 85 people globally by 2050.

Although Alzheimer's disease  54  differently for every individual, there are many common symptoms. Early symptoms are often  55  thought to be "age-related" concerns, or  56  of stress. In the early stages, the most common symptom is difficulty with remembering recent events. When AD is  57 , the diagnosis is usually confirmed with tests that evaluate behaviour and thinking abilities, often followed by a brain scan if  58  As the disease advances, symptoms can include confusion, irritability and aggression, mood swings, trouble with language, and long-term memory loss. As the sufferer declines they often  59  from family and society. Gradually, bodily functions are  60 , ultimately leading to death.