Alzheimer disease

Although the course of Alzheimer's disease is unique for every individual, there are many common symptoms.[4] The earliest observable symptoms are often mistakenly thought to be 'age-related' concerns, or manifestations of stress.[5] In the early stages, the most commonly recognised symptom is inability to acquire new memories, such as difficulty in recalling recently observed facts. When AD is suspected, the diagnosis is usually confirmed with behavioural assessments and cognitive tests, often followed by a brain scan if available.

As the disease advances, symptoms include confusion, irritability and aggression, mood swings, language breakdown, long-term memory loss, and the general withdrawal of the sufferer as their senses decline.[5][7] Gradually, bodily functions are lost, ultimately leading to death.[8] Individual prognosis is difficult to assess, as the duration of the disease varies. AD develops for an indeterminate period of time before becoming fully apparent, and it can progress undiagnosed for years. The mean life expectancy following diagnosis is approximately seven years.[9] Fewer than three percent of individuals live more than fourteen years after diagnosis.