In a new report published in the journal Brain, a group of international researchers define the diagnostic criteria and research guidelines for a newly-named type of dementia called LATE.
LATE, which tends to appear in very old people, may seem like Alzheimer’s to the layperson, but inside the brain, the disease looks quite different. The incidence of LATE is almost as prevalent among the oldest-old as Alzheimer’s.
In the past, using the terms “Alzheimer’s disease” and “dementia” interchangeably was common. Then scientists began noticing that a large number of people who died in very old age had symptoms of dementia without the telltale signs of amyloid or another common culprit, tau, in their brains at autopsy.
Now there is rising appreciation that a variety of diseases and disease processes contribute to dementia.
“More than 200 different viruses can cause the common cold,” said Dr. Peter Nelson of the Sanders-Brown Center on Aging at the University of Kentucky, “So why would we think there is just one cause of dementia?”
In fact, it is very likely that many of the people who enrolled in earlier clinical trials for Alzheimer’s drugs did not have amyloid, the sticky substance that gums up neurons and interferes with thinking.
“Recent research and clinical trials in Alzheimer’s disease have taught us two things: First, not all of the people we thought had Alzheimer’s have it; second, it is very important to understand the other contributors to dementia,” said Nina Silverberg, Ph.D., director of the Alzheimer’s Disease Centers Program at National Institute on Aging (NIA), part of NIH.
The group’s work establishes that like Alzheimer’s disease, LATE affects multiple areas of cognition, ultimately impairing activities of daily life, but it appears that LATE progresses more gradually than Alzheimer’s. However, LATE combined with Alzheimer’s — which is a common combination — appears to cause a more rapid decline than either would alone.
Nelson likens the team’s work to Benjamin Franklin’s “discovery” of electricity.
“People had seen lightning before of course, but Franklin helped formalize a concept that augmented our ability to study electricity,” he said. “By developing a sense of scientific focus around these data, we hope to jump-start a broad field of work to advance our understanding of this form of dementia and, ultimately, to open new opportunities for treatment.
Most importantly, Nelson added, it’s time to stop thinking of dementia as a “one-size-fits-all” disease.
“LATE probably responds to different treatments than AD, which might help explain why so many past Alzheimer’s drugs have failed in clinical trials,” he said. “Now that the scientific community is on the same page about LATE, further research into the ‘how’ and ‘why’ can help us develop disease-specific drugs that target the right patients.”
Source: University of Kentucky