Johns Hopkins University's Marilyn Albert, a professor of neurology and psychiatry, says these steps are essential in diagnosing Alzheimer's disease: A complete medical history, including signs of cognitive decline. Evidence must be corroborated with a close relative. Laboratory tests to rule out other medical problems should include, among others, blood tests for a vitamin B12/folate deficiency; thyroid problems; and tests to assess liver and kidney function. (Problems in any of these body systems could cause memory and thinking difficulties). MRI or CT brain scans to rule out tumors, stroke or hydrocephalus, other causes of cognitive decline. A screening for symptoms of depression. Simple cognitive testing designed to spot dementia should be repeated over time to spot worsening of symptoms. Copyright © 2004, Newsday, Inc.