June 18, 2014

New Test for Earlier Alzheimer's Diagnosis?

Can science differentiate between Alzheimer’s and the effects of normal aging? In a study published in the journal Neuropsychologia, researchers at the University of Illinois at Urbana-Champaign claim to have identified a new and measurable way.

The duo who led the work -- psychology professor Neal Cohen, who is affiliated with the Beckman Institute at Illinois, and Jim Monti, a University of Illinois postdoctoral research associate – based their study design on information we already know about the hippocampus. That’s the region of the brain that’s key in “relational memory,” the ability to fasten together various related, but separate, bits of information.

Monti explains: connecting a person’s face with her name – data stored in two different parts of the brain – is an example of relational memory. The hippocampus somehow “binds” the two pieces of information, so the next time you see that face, you know it’s Jennifer.

Earlier studies had already established that people with Alzheimer’s often show damage to the hippocampus. So Monti and Cohen devised a test they thought would assess the functioning capacity of that particular part of the brain among their subjects -- young adults, healthy older adults, and individuals with very mild Alzheimer's disease.

Assessing Hippocampus Function
How might you do that?

The team showed their subjects a circle divided into three parts, each part with its own unique design. If the hippocampus was functioning well, it would bind the three sections together – like it does when we see Jennifer and remember her name – and enable us to recognize it later.

After subjects had studied the circle for a while, they were asked to identify that circle from a series of ten circles, shown one at a time. From those ten options, study participants would choose the match.

This graphic -- though it's hard to really understand out of context -- provides a flavor of what participants saw:

         

Not surprisingly, participants with very mild Alzheimer’s were least able to identify the correct circle matches. Next came the healthy older adults. The young adults showed the best matching abilities.

The Sooner, the Better
The study designers think their test provides a new and quantifiable way to differentiate Alzheimer’s brains from brains of adults who are aging normally. Monti believes this new tool can help identify Alzheimer's more accurately than some of the classic tests now used in diagnosis. "That was illuminating and will serve to inform future work aimed at understanding and detecting the earliest cognitive manifestations of Alzheimer's disease," he said.

As is the case with all diseases, the earlier the diagnosis, the better the chances to treat the patient. Indeed, drug treatments for AD patients have shown the best results among people in the very early stages of the disease. For now, there’s only one sure way to classify a human brain as Alzheimer’s afflicted – autopsy… not exactly a useful diagnostic tool for the patient.

Monti adds the usual caveat: while this new test might eventually find its way into clinical practice, more and larger studies are needed to refine it.

The clock is certainly ticking. About five million Americans have Alzheimer’s disease now. The Alzheimer’s Association estimates that the number will jump to about 16 million by 2050.

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Is it Alzheimer’s, or Something Else?
If you can't get your hippocampus function assessed anytime soon, the online journal "Health Line" offered this primer on Alzheimer’s and dementia:

The Dementia/Alzheimer’s Connection
Many people use the words “dementia” and “Alzheimer’s disease” interchangeably. However, they’re not the same thing. You can have a form of dementia that is completely unrelated to Alzheimer’s disease.

Although younger people can develop dementia and/or Alzheimer’s disease, your risk increases as you age. Still, neither is considered a normal part of growing older.

Dementia Is a Group of Symptoms
Dementia isn’t a disease. It’s a group of symptoms that affect mental tasks like memory and reasoning. Dementia can be caused by a variety of conditions, the most common of which is Alzheimer’s disease.

As dementia progresses, it can have a devastating impact on the ability to function independently. It’s a major cause of disability for older people, and places an emotional and financial burden on families and caregivers.

The World Health Organization (WHO) says that 35.6 million people around the world are living with dementia.

Signs of Dementia
Early symptoms of dementia can be mild and easily overlooked. It often begins with simple episodes of forgetfulness. People with dementia have trouble keeping track of time and tend to lose their way in familiar settings.

As dementia progresses, forgetfulness and confusion grow. It becomes harder to recall names and faces. Personal care becomes a problem. Obvious signs of dementia include repetitious questioning, inadequate hygiene, and poor decision-making.

In the most advanced stage, dementia patients become unable to care for themselves. Time, place, and people become more confusing. Behavior continues to change and can turn into depression and aggression.
Causes of Dementia
Dementia is a problem of the brain that you’re more likely to develop as you age. Many conditions can cause dementia, including degenerative diseases like Alzheimer’s, Parkinson’s, and Huntington’s.

According to the Cleveland Clinic, Alzheimer’s disease is responsible for 50 to 70 percent of all cases of dementia.

Infections such as HIV can trigger dementia. So can vascular diseases and stroke. Depression and chronic drug use are other possible causes.

Alzheimer’s Is a Disease
Alzheimer’s is a progressive disease of the brain that slowly impairs memory and cognitive function. The exact cause is unknown and there is no cure.

The National Institutes of Health (NIH) estimate that more than five million people in the United States have Alzheimer’s disease. Although younger people can (and do) get Alzheimer’s, symptoms generally begin after age 60.

The time from diagnosis to death can be as little as three years in people over 80 years old. However, it can be much longer for younger people.

The Alzheimer’s Brain
Damage to the brain begins years before symptoms show. Abnormal protein deposits form plaques and tangles in the brain of someone with Alzheimer’s disease. Connections between cells are lost and they begin to die. In advanced cases, the brain shows significant shrinkage.

It’s impossible to diagnose Alzheimer’s with 100 percent accuracy while a person is alive. The diagnosis can only be confirmed during an autopsy, when the brain is examined under a microscope. However, specialists are able to make the correct diagnosis up to 90 percent of the time, according to the NIH.

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