Detecting Alzheimer's Early

[magenta321]

Alzheimer’s Disease - Memory - Brain - Genetics - Medicine and Health - New York Times

PET scans can show biochemical changes in the brain early in the disease. While there is no cure for dementia, it can mean that the patient and their family can make decisions while the patient is an active participant in the process.

I wrote a newsletter on this for work a while back, and I've received a few "thank yous" because people didn't know the process for diagnosising dementia (or why you should bother because it seems inevitable for some). If you suspect you or someone you love is forgetting more than normal, talk to a doctor. They can help rule out other conditions and decide if further testing is necessary.

[mjfrombuffalo[$]]

I'm confused. While you're saying it's a definite, the experts int he article you linked are referring to it as experimental.

A radioactive dye called PIB (for Pittsburgh Compound B) has made it possible to use PET scans to find deposits of amyloid, an Alzheimer’s-related protein, in the brains of live human beings. It may lead to earlier diagnosis, help doctors distinguish Alzheimer’s from other forms of dementia and let them monitor the effects of treatment.

Studies with the dye have already found significant deposits in 20 percent to 25 percent of seemingly normal people over 65, suggesting that they may be on the way to Alzheimer’s, though only time will tell.

“PIB is about the future of where Alzheimer’s disease needs to be,” said Dr. William E. Klunk, a co-discoverer of the dye at the Alzheimer’s research center at the University of Pittsburgh. “PIB is being used today to help determine whether drugs that are meant to prevent or remove amyloid from the brain are working, so we can find drugs that prevent the underlying pathology of the disease.”

Though PIB is experimental now, studies began in November that are intended to lead to government approval for wider use.

The article starts out with healthy people with Alzheimer's in their family who are undergoing all sorts of tests to find out what might be early signs or markers of the disease, nothing definitive. The whole article is full of words like "might" and "speculating" and "I think" and "possibly." Don't get me wrong, it would be great to be able to send my FIL for a test to tell us if he's got normal forgetfulness, forgetfulness because of poor diet or something else fixable, or Alzheimers, but this article doesn't point to a definitive conclusion on the tests mentioned.

[magenta321]

That is a good question, MJ. I'm not a doctor, nor will I pretend to be.

It's something they're fighting for more insurances to cover. I'll try to ask my doctors tomorrow for more clarification as to why this article would be hedging so much. No one has hedged when discussing this matter with me, nor did I hedge when I wrote my article (which had to be approved by multiple radiologists before it was printed). As soon as I can get a better answer for why the NYT was hedging, I will.

[pippadaisy[$]]

I'm guessing because it doesn't have FDA approval?

The paper was just published in 2004. In a 2005 interview one of the researchers gave to the journal of his own university, he said it could be commercially available within a decade.

Insurance isn't going to approve something that the FDA hasn't given the A-OK to.

[magenta321]

Medicare pays since 2004. Since other insurance companies follow Medicare-guidelines, they mostly pay too.

I asked one of my Radiologists to explain to me why the NYT was hedging. He said it is because it's one piece of the puzzle. Here's my non-doctor understanding of what he said:

Basically, if you're completely demented, this will show it and it will be obvious. But at that point, did you really need a test to show you were demented? Everyone already knew.

This is helpful to the person who is getting diagnosed early. PET is going to indicate whether or not you might have the early signs of it, but it will be a part of many other tests.

The following tools currently diagnose a patient with possible dementia:

 Interviews with patient and family to determine if there is a cognitive problem
 Physical exam, especially vascular
 Neurological exam to check for sensory or motor problems
 Mental state exam to evaluate psychiatric illness
 Blood tests to rule out chemical, hormonal, or infectious illness

Current standard imaging includes a CT scan or MRI to rule out anatomic or pathologic abnormality.

He listed all of that but it was in my newsletter so it was just much easier to quote it than to try to remember and retype all of that. So anyway... PET is one part of the diagnosis. They will look at all this other data too before they come up with a diagnosis.

He also mentioned that there are different forms of dementia, including Alzheimer's, alcohol-induced dementia, and many forms of dementia they just don't understand yet. This could also be why the Times was hedging.

[pippadaisy[$]]

The NYT wasn't talking about PET... they were talking about the specific tracer developed by the team who developed PIB.

[magenta321]

I am (maybe incorrectly) assuming PIB is the isotope used during routine PET/CT scans. I'll try to verify that next week.

[mjfrombuffalo[$]]

They also debated the role of the specific substance the PIB was finding, and whether that was actually something the brain needs to have, not necessarily a marker for early Alzheimer's. At least its something to check out, I'm glad this kind of research is going on.

[Helen_B[$]]

I had read in books published several years ago that PET scans could help a doctor differentiate between a number of things, depending on which part of the brain showed normal activity and which didn't. I understood that the PET scan was one way to narrow a diagnosis, because the scan would be different for someone suffering from anxiety than it would for someone who was depressed, and different for ADHD than it would for some other learning disabilities. Also, the scan could help spot Alzheimer's. I have an idea that the chance of having a PET scan in Ontario in time to be helpful in diagnosing Alzheimer's would be slim to none.