title: Alzheimer's disease
context: The cause of Alzheimer's disease is poorly understood.[1] About 70% of the risk is believed to be genetic with many genes usually involved.[4] Other risk factors include a history of head injuries, depression, or hypertension.[1] The disease process is associated with plaques and tangles in the brain.[4] A probable diagnosis is based on the history of the illness and cognitive testing with medical imaging and blood tests to rule out other possible causes.[5] Initial symptoms are often mistaken for normal ageing.[1] Examination of brain tissue is needed for a definite diagnosis.[4] Mental and physical exercise, and avoiding obesity may decrease the risk of AD; however, evidence to support these recommendations is not strong.[4][12] There are no medications or supplements that have been shown to decrease risk.[13]
question: How is Alzheimer's diagnosed?
answers.text: based on the history of the illness and cognitive testing with medical imaging and blood tests to rule out other possible causes