16 November 2016 - Futurity - Alzheimer's didn't cause memory loss for these 90-year-olds

Scientists looked at the brains of eight people older than 90 who had superior memories until their deaths. They were surprised to find widespread and dense Alzheimer’s plaques and tangles that were, in some cases, considered full-blown Alzheimer’s pathology.

“This is amazing,” says lead investigator Changiz Geula, research professor at the Cognitive Neurology and Alzheimer’s Disease Center at Northwestern University.

“We never expected it. It tells us there are some factors that are protecting their brains and memories against the Alzheimer’s pathology of plaques and tangles. Now we have to find out what those are.”

The findings are the first to indicate that full-blown Alzheimer pathology can also exist in the brains of elderly who show superior cognitive performance.

Extensive plaques and tangles in the brain result in the death of neurons and are an indicator of Alzheimer’s dementia. The fact that some elderly with the pathology still had superior memory points to mechanisms that offer protection. Discovery of what they are could likely help the development of therapies against Alzheimer’s disease, Geula says.

“Now we have to search for factors that protect these elderly against memory loss. We will look at genetic, dietary, and environmental influences that could confer protection for neurons against Alzheimer’s pathology.”

If scientists can find a protective environmental factor, it could help both the normal elderly and those with the Alzheimer’s pathology, Geula says.