Millions of elderly people have a form of dementia that has been misdiagnosed as Alzheimer’s disease, according to researchers.
One expert has called it the most important dementia finding in years.
The condition, limbic-predominant age-related TDP-43 encephalopathy, or Late, shares similar symptoms to Alzheimer’s, but it is a distinct disease, the journal Brain reports.
It may partly explain why finding a dementia cure has failed so far.
Dementia is not a single disease, but is the name for a group of symptoms that include problems with memory and thinking.
There are lots of different types of dementia and Alzheimer’s is said to be the most common and most researched.
But up to a third of Alzheimer’s in elderly people may instead be Late, says the international team of researchers, although both dementias can co-exist.
Furthermore, Late appears to affect the “oldest old” – people over 80 – according to the work that looked at evidence from thousands of post-mortem results.
One in five in this age group has it, meaning the public health impact of the disease will be large, say the researchers.