Alzheimer's is the most common form of dementia, a brain disorder that primarily affects the elderly. Scientists still aren't sure what causes the disease, and there is no cure. It is named after a German doctor, Alois Alzheimer, who in 1906 noticed anomalies in the brain tissue of a woman who had died of a strange mental illness. There were abnormal clumps (amyloid plaques) and tangled bundles of fibers, both of which are the most common signs of Alzheimer's.

Evidence suggests that only plaques are associated with the earliest symptoms of Alzheimer's. Other brain changes can occur. Nerve cells die in areas of the brain vital to memory and other mental abilities, and the connections between nerve cells are disrupted, impairing thinking and memory. It is projected that the prevalence of Alzheimer's will nearly quadruple in the next 50 years, by which time approximately 1 in 45 Americans will be afflicted with Alzheimer's.

Alzheimer's is a slow-moving disease, and in its earliest stages, may merely appear to be mild forgetfulness, and confused with age-related memory change. There may be problems remembering recent events or activities, or the names of familiar people or objects. As the disease progresses, the forgetfulness becomes more severe, interfering with daily activities, such as brushing one's teeth. There are problems speaking, understanding, reading or writing, and eventually the brain damage becomes so severe as to require total care.

Alzheimer's still cannot be conclusively diagnosed in any way other than post-mortem brain examination. However, a contrast agent called Pittsburgh Compound-B, or PIB, used in conjunction with PET scans, has the potential to diagnose Alzheimer's in living patients by binding to the telltale amyloid plaque deposits This non-invasive technique can give researchers information about how and where Alzheimer's progresses in the brain, as well as the efficacy of treatment.

The pattern of PIB retention in the brain suggests that amyloid plaques formed by Alzheimers appearing first in the frontal cortex areas, and then progressing to the parietal and temporal cortex before ravaging the occipital and sensory-motor cortex. This may explain why memory and judgment are often the brain functions first affected with the onset of the disease.

Treating and Preventing Alzheimer's