Saturday, May 17, 2014

An Alzheimer's Blood Test: Would You REALLY Want to Know the Result?

Janice's cousin Desmond was once a man of quick wit and endless curiosity, especially about astronomy and cosmic physics. When I saw Desmond in 2003 at the family vacation beach house, we had a long  conversation and debate about the mass limits of stellar black holes and also the estimated mass of the galaxy-gobbling hole at the center of the Milky Way. In the meantime, I was preparing to give a lecture on dark energy at the local observatory, and so Desmond also wanted to know everything about that: How could it be detected? What specific data did one look for? What would be the long term consequences to Earth, and any sentient beings inhabiting planets? Could it affect the expansion of the universe, and if so, how? How much of the universe did dark energy comprise and how much in relation to its counterpart, dark matter?

Desmond (as shown in the photo) was the epitome of a bright, curious and probing mind. Merely seven years later, he was reduced to a hollow shell of a man, and his intellect only a faint wisp. He could barely recall even basic events, far less engage in a conversation about dark energy or stellar black holes. Worse, the prognosis was that his condition would surely degenerate, to the point he wouldn't even be able to wash himself or use the toilet. Within a year or so, he might be reduced to a babbling baby, even as he continued to avoid eating much. He was in the personal Hell of Alzheimer's disease.

By 2013, the disease had extracted the ultimate toll and Desmond died of asphyxia, in his sleep. Our last partial conversation with him was in 2010, when he'd drift in and out of coherence and even briefly recalled an ASTRONOMY magazine I'd lent him three years earlier. Three quarters of the time, however, he spent in incoherent babble.

I recount this story because the scourge of Alzheimer's disease is on just about everyone's mind these days - well, okay, at least on the minds of those of us over 65. You see, every five years past the age of 65 the number of people with Alzheimer's doubles. No one knows up to now how this disease, which will eventually bankrupt the country, can be stopped.

However, the AARP Bulletin in a recent piece ('Would You Want to Know?', May, p. 20) noted researchers in the field have announced a promising new blood test that could let people know if they have the telltale Alzheimer's markers.  As noted by a professor of neurology at Georgetown Medical Center,  quoted in the article:

"The main problem with treating Alzheimer's disease today is that the medicines are probably given too late to do much good."

He went on to state:

"Our research reports a bio-marker that will allow us to select patients who have very early disease, and we can determine whether medicines are more effective if given earlier."

While this blood test "offers important clues", it isn't perfect. It has about a 90 percent accuracy rate. But the test offers important clues nonetheless. For example the changes observed are believed to be due to the breakdown of brain cell membranes in people destined to develop the disease. The researchers are also continuing to look at other molecules in the blood that could provide a more detailed view of people at risk.

Assuming this test is made generally available and improved, would anyone really want to know if Alzheimer's is lurking? Please note this isn't the same as getting a psa test. The latter - say if it reveals high levels of psa and cancer is confirmed by a biopsy - can at least be treated. Alzheimer's is the only one of the top ten killer diseases that can't be prevented or treated.

This means any result from a test that predates a useful treatment regimen would be sterile, and even have negative impacts on the person. Craig Klugman, a bioethicist quoted in the article, observes:

"A positive result on a test like this could be devastating. It could change people's outlook on life, making them anxious, depressed and withdrawn. Suddenly, you find yourself living with this sense of doom that can effect every dimension of your life."

Those who test positive could also suffer the added burden of feeling stigmatized or ashamed. I mean, you know you have this defect of the brain - never mind it wasn't by choice - and now that you have this knowledge it eats away at your confidence, choices and words. Is this the Alzheimer's talking or me?  Worse, every little memory lapse is now magnified to a major calamity. "Jeezus Peace, where did I leave my keys? Omigod, it IS Alzheimer's!"

As each new lapse, or faux pas occurs, the stigma is reinforced and the affected person becomes more withdrawn. Soon he identifies with the disease and it becomes his very manifestation. 

Nor is this empty speculation. A recent study cited in the AARP article looked at the effect of telling people that they carry a genotype that puts them at high risk of developing Alzheimer's. Those who tested positively judged their memories more critically as well as every lapse. They also performed worse on memory tests than those not informed.

Get a blood test to identify Alzheimer's bio-makers ahead of time? You want me to take it?

Nope, I don't think so! Until viable treatment options exist there's no point in knowing.

1 comment:

Seek Find said...

Thanks for bringing dementia to your always interesting blog. Dementia is a whispered disease without any cheerleaders.