The doctor will use evidence from a careful exam and a process of elimination to arrive at a diagnosis. A combination of diagnostic tools enables him to screen for conditions that may be affecting your loved one. Here's a quick breakdown:

• A medical history. The doctor will ask a series of questions about medical conditions and illnesses he or she has had in the past, any current medical symptoms or medications, and information about other family members' health. He may ask about other topics as well, such as diet and exercise.
• A physical exam. As in a regular checkup, the doctor will check his or her vital signs -- blood pressure, pulse, and temperature. He'll also listen to his or her heart and lungs and check other physical characteristics.
• Diagnostic tests. The doctor will order urine and blood tests to check for certain infections or disorders that may be causing symptoms. Blood testing may be used to search for genes known to make Alzheimer's more likely.
• A mental status assessment. Your loved one will be asked to answer a series of questions and perform some activities in order to evaluate memory loss, disorientation, trouble with following directions or completing basic tasks, problem-solving ability, communication skills, and awareness of the problems he or she experiences. The doctor may also ask questions to assess for depression, anxiety, and other possible psychiatric problems.
• A neurological or neuropsychological evaluation. The doctor may test his or her physical coordination, reflexes, balance, and speech, among other indicators of neurological health.
• A brain scan. It's likely the doctor will order either a CT (computer tomography) scan or MRI (magnetic resonance imaging) scan to visually examine the condition of his or her brain, including possible damage due to Alzheimer's disease, trauma, or strokes.
• Other tests. The doctor may also order other tests or scans, such as a spinal tap, a chest X-ray, an electroencephalogram (EEG, to examine brain function by the electrical activity it generates), or a positron emission tomography scan (a PET scan, to examine the function of internal organs).