By Kathleen Fackelmann, USA TODAY

Sally King, 62, remembers watching helplessly as Alzheimer's disease stripped her mother's mind of rational thought.

		Brain scans may show Alzheimer's in her future, or not.
		By Bob Riha Jr., USA TODAY

"It's your worst nightmare," she says of the relentless progression from her mother's mild forgetfulness to her inability to dress herself or even talk.

Now King, a retired lawyer from Lake Sherwood, Calif., has signed up for a study of a high-tech imaging technique, one that allows researchers to scan the brain for a telltale marker of Alzheimer's.

"I'm praying for a good report," she says.

If they pan out, new imaging methods such as the one being tried on King might soon offer a diagnosis of Alzheimer's at an earlier, and possibly more treatable stage. Today, doctors often can't easily distinguish between routine forgetfulness and the more serious memory problems of Alzheimer's.

Currently, neurologists use brain scans to look at how well the memory regions of the brain work, an indirect tool that can help in the diagnosis of Alzheimer's disease. But with the experimental scans, researchers can now look directly at the progressive loss of brain cells or the buildup of Alzheimer's plaque, abnormal brain deposits that are hallmarks of the disease. (Related item: Painkillers may dissolve Alzheimer's plaque)

The scanning methods also may give researchers a better way to test the impact of a potential new drug for Alzheimer's, which affects 4 million people in the USA. For instance, researchers at UCLA were able to use part of one experimental scanning technique to see how painkillers affect Alzheimer's plaque in a test tube.

For the first time, researchers have captured on film the destruction of a human mind by Alzheimer's. Paul Thompson, a researcher at the University of California-Los Angeles, and his colleagues have developed a three-dimensional color video of the human brain as it succumbs.

Thompson and his colleagues studied 12 people who had just gotten a diagnosis of Alzheimer's. The team used a standard magnetic resonance imaging (MRI), but then added a computer analysis that detects very subtle changes in the MRI pictures of the brain, taken over a two-year period. The end result: a time-lapse video that shows a wave of brain-cell death.

"Alzheimer's is like a lava flow that's engulfing more and more of the brain," Thompson says.

The first images of the brain show the disease has already killed thousands of cells in the memory region, a finding that fits with the clinical observation that by the time patients get a diagnosis, they've already experienced serious memory loss. As time goes on, the video shows that devastation starts to include brain regions that govern behavior and emotion. When the cells in those regions die, the Alzheimer patient starts to experience symptoms like aggression, rage or difficult-to-manage behaviors like wandering.

Two years into the disease, the video shows a brain that has lost about 20% of its gray matter.

While Thompson's team has focused on brain-cell death, another team at UCLA has zeroed in on Alzheimer's plaque, clumps of an abnormal protein called beta amyloid surrounded by dead brain cells. In the past, doctors could see these abnormal deposits only during an autopsy exam of the brain.

Gary Small, also at UCLA, and his colleagues have developed a positron emission tomography (PET) scanning method that looks at the Alzheimer's plaque in the living human brain. To develop the method, the team first identified a chemical marker, or probe, that sticks to beta amyloid, which is thought to kill brain cells. Next, Small's team put the chemical probe into a solution and injected it into the bloodstream. Using a PET scanner, the team snapped pictures that revealed the probe attached to the Alzheimer's plaque.

The team tested the method on nine Alzheimer's patients, and the scans showed the abnormal pattern of plaque typically seen during an autopsy study. When the team did the same scans on healthy people, they found a very small amount of plaque, which may be a sign of normal aging.

William Klunk, a researcher at the University of Pittsburgh School of Medicine, and a team led by Bengt Langstrom of the Uppsala University in Sweden have developed another PET technique that makes plaque visible. This one uses a different chemical marker.

So far, the team has taken brain snapshots of nine Alzheimer's patients. In eight of the nine, the images revealed plaque in the same brain regions known to be affected by this disease. One of the patients didn't have the usual pattern. Klunk suspects this patient may have had another condition that causes memory loss.

Small says plaque may start to form at least a decade before Alzheimer's symptoms emerge. Researchers believe the buildup is silent at first, perhaps because not many brain cells have died and people compensate for those that have succumbed. But as time goes on, plaque accumulation starts to kill brain cells in earnest. That's when people start to suffer from obvious signs of forgetfulness

Sally King believes the new research will yield new treatments —that's why she's signed up for the UCLA PET scanning study. Today Alzheimer's patients can take drugs that ease the symptoms, but there is no cure for this disease.

King knows this. She also knows that she has a higher risk of getting the disease. She has no signs of Alzheimer's, but her mom developed the disease in her late 60s, and King is taking no chances.

She's already taking naproxen, a drug that may melt away plaque, according to preliminary research. If it works, the drug may buy people like King more time. "I am hoping for a cure," she says.