Scanning for Alzheimer’s

By Medical Discovery News

Sept. 15, 2012

Alzheimer's affects 5.4 million Americans

At first it seems to be occasional forgetfulness, followed by jokes of Mom having another “senior” moment. Then her lapses start to get serious. A teapot left on the stove starts a fire. The family doctor suspects she has dementia, which a neurologist confirms, but when asked if it’s Alzheimer’s Disease, doctors can only guess. Today, the only method available to confirm someone had Alzheimer’s is through an autopsy.

Having the ability to diagnose Alzheimer’s while someone is alive can help rule out other possible conditions such as a drug’s side effects or depression, which can cause similar early symptoms.   Patients could then begin therapies to manage the disease and allow families to make necessary accommodations.

A test recently approved by the Food and Drug Administration combined with clinical symptoms can get doctors pretty close to a diagnosis. The test uses a weakly radioactive fluorescent dye called Amyvid that latches on to amyloid plaques in the brain. Amyloid plaques are protein fragments that normally break down, but in people with dementia they accumulate into hard insoluble plaques. It’s unclear whether amyloid plaques cause Alzheimer’s, but their presence is indicative of the disease. Once Amyvid binds to the plaque, a positron emission tomography or PET scan reveals the location and amount of protein clusters in the brain.

While a clear scan is a relief, patients with a positive scan don’t necessarily have Alzheimer’s. Twenty to 30 percent of people over 65 have some plaque and may never develop dementia. But the test is significant to Alzheimer’s research since it will allow scientists to identify and track people with dementia, expanding their knowledge about the causes of Alzheimer’s and its progression. Scientists can also monitor how the disease develops under experimental therapeutics.

Finding effective treatments for Alzheimer’s will become increasingly important as America’s population ages. It is the No. 1 cause of dementia, affecting 5.4 million people. That number is expected to double in the coming years. By 2050, the cost to treat people with Alzheimer’s is projected to soar to $1.1 trillion.

Currently, there is no cure for Alzheimer’s. Some drugs appear to slow its progression, but the benefit is disappointingly small. Most of what can be done is manage symptoms. While scientists don’t yet fully understand what causes Alzheimer’s, it’s clear the illness develops under a complex series of events in the brain over a long period of time. The causes likely include some mix of genetic, environmental, and lifestyle factors.

Typical symptoms of Alzheimer’s include difficulties performing routine tasks and learning new information, getting lost on familiar routes, language problems, and personality changes. Eventually the memory declines to the point where family members aren’t recognized, language is lost, and basic functions such as eating and dressing require help.

This is only one of many studies into understanding Alzheimer’s that could lead to promising diagnostics and treatments.

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