According to the Alzheimer's Association, 5.4 million adults in the United States have a type of dementia called Alzheimer's disease. The organization added that 200,000 of these people have early onset Alzheimer's disease, in which symptoms begin before age 60, and 5.2 million have late onset Alzheimer's disease, in which the symptoms begin age 60 or older.
As Alzheimer's disease progresses, patients can have more severe cognitive dysfunction and impairment. In the stage before Alzheimer's disease,
MedlinePlus explained that there is only one exact way of diagnosing Alzheimer's disease: examining the brain tissue after the patient's death for the presence of plaques and tangles. Since there is a need to diagnose the condition while the patient is alive, other tests can be done to help rule out other causes, such as vitamin deficiency or thyroid problems. Possible diagnostic tests for Alzheimer's include a physical examination, neuropsychological testing and brain scans, such as a CT scan or MRI scan. One evaluation that may be done during the physical examination is to take a sample of the patient's spinal fluid for analysis. For example, doctors may look if the patient has an imbalance of two proteins involved in Alzheimer's disease: beta amyloid and tau. Beta amyloid group together to form plaques.