When There's No Amyloid, It’s Not Alzheimer’s

[stanleypj]

This is the heading to a fascinating article in the latest Alzforum weekly newsletter. Here's a link to the article:

http://www.alzforum.org/news/research-news/when-theres-no-amyloid-its-not-alzheimers?utm_source=Alzforum+Weekly+Newsletter&utm_campaign=0372e368ea-September_14_2015_Newsletter&utm_medium=email&utm_term=0_944a562dd7-0372e368ea-91738709

And the first paragraph gives you the gist:

Reporting in the August 24 JAMA Neurology online, researchers led by Eric Reiman at Banner Health in Phoenix, confirm what others have suspected from PET imaging, namely, that as many as one-third of the people clinically diagnosed with mild to moderate Alzheimer's disease do not meet criteria for significant amyloid accumulation in the cerebral cortex. Reiman and colleagues came to this conclusion after examining brain tissue postmortem—the gold standard for assessing amyloid burden. The finding puts the kibosh on the idea that some PET scans are negative because amyloid ligands bind poorly to particular forms of amyloid in some AD patients. It also reinforces questions about the accuracy of clinical diagnoses of AD and leaves the field struggling to explain what causes dementia in these amyloid-negative individuals. This promises to be an intense area of investigation, said Reiman.


Articles like these are often difficult for a lay person to understand. But from what I can understand and already know I would say the title is begging the question a tad. It should be no surprise that many people diagnosed with AD are found post mortem not to have amyloid accumulation in their brains. But surely this could be because either, as the title says, people without the amyloid must have a different disease or different diseases OR because, as other research suggests, amyloid accumulation is not as significant in AD as is so often claimed.

 

[nitram]

Let's go back 109 years.

"...it was in 1906 that Alzheimer gave a lecture that made him famous. In it, Alzheimer identified an 'unusual disease of the cerebral cortex' which affected a woman in her fifties, Auguste D., and caused memory loss, disorientation, hallucinations and ultimately her death aged only 55. The post-mortem showed various abnormalities of the brain. The cerebral cortex was thinner than normal and senile plaque, previously only encountered in elderly people, was found in the brain along with neurofibrillary tangles. Alzheimer had access to a new stain and was able to identify these nerve tangles which had never previously been described. Kraepelin named the disease after Alzheimer....

...Today, the pathological diagnosis of Alzheimer's disease is still generally based on the same investigative methods used in 1906. This is remarkable compared with the development of investigative methods for other diseases, and it speaks volumes about the quality of Alzheimer's discovery..."

http://www.alz.co.uk/alois-alzheimer

In the absence of significant post mortem studies the common phrase for anybody with dementia was senile dementia, this somehow changed and Alzheimers became the acceptable phrase, I think some professionals still use it as a blanket name to make life easier. My wife's consultant referred to her diagnosis as 'Lewy body variant of Alzheimer's disease'.

People used to be said to have cancer, now it's more likely to be cancer of <parts or parts of body affected>.

In my opinion if people were diagnosed with dementia of <parts or parts of brain affected> this could give a more reliable estimate of the speed and nature of progression, as with cancer there is nothing to stop the disease spreading and affecting the prognosis.

How many people actually ask to look at scans and have them explained, I did and could see the progression in various parts of the brain, it gave me clues as to what might come next.

 

[stanleypj]

Yes, I would doubt whether it's very common to ask to see the scan. I suppose it's your science background that prompted you to.

 

[stanleypj]

That's a very interesting site you've linked to nitram. Thanks. I think the infographic will be of some interest to TPers.