CHICAGO — A rare type of dementia that causes brain changes similar to Alzheimer’s disease, still preserves a patient’s memory, scientists believe. Primary progressive aphasia (PPA) is a neuro-degenerative disorder that affects areas of the brain linked to language.
A recent study finds that people with aphasia may not develop the same problems as people with typical Alzheimer’s. The study sheds fresh light on a disease that has been described by Alzheimer’s Research UK in Cambridge, England, as “the greatest health challenge of our time.”
“While we knew that the memories of people with primary progressive aphasia were not affected at first, we did not know if they maintained their memory functioning over years. This has been difficult to determine because most memory tests rely on verbal skills that these people have lost or are losing,” says study lead author Dr. Marek Marsel Mesulam of Northwestern University, in a statement.
The study compared 17 sufferers of aphasia to 14 people who had typical Alzheimer’s with memory loss. The aphasia group had no decline in their powers of recollection over around two and a half years. They had been showing symptoms for about six years. In contrast, their language skills declined significantly during the same period. The Alzheimer’s group’s verbal memory and language skills declined with equal severity.
“More research is needed to help us determine what factors allow these people to show this resilience of memory skills even in the face of considerable Alzheimer’s disease pathology in the brain,” said Dr. Mesulam.
The study’s aphasia participants were presented with pictures of common objects and then had to say if they had seen them before when shown them again ten minutes later, along with other images. This was repeated an average of 2.4 years later.
Aphasia restricts one’s ability to speak, but memory doesn’t suffer
Participants with Alzheimer’s listened to a list of common words and were later given those words along with others and asked to choose the ones they had heard before. They were tested again an average of almost two (1.7) years later. Both groups also had their language skills tested.
Scans were taken of the people with PPA to look at how the disease was affecting their brains, especially in the areas related to memory. The study also analyzed brain autopsies from eight of the people who later died with primary progressive aphasia and all of those with typical Alzheimer’s. “The aphasia group had similar amounts of the plaques and tangles that are the hallmark signs of Alzheimer’s,” says Mesulam.
There was less shrinkage on the left side of the brain of aphasia patients and a lower incidence of proteins known as ApoE4 and TDP-43. These proteins were identified as potential contributors to the preservation of memory in this rare form of Alzheimer’s.
The National Aphasia Association describes PPA as a neurological syndrome in which language capabilities become slowly and progressively impaired. “It commonly begins as a subtle disorder of language, progressing to a nearly total inability to speak, in its most severe stage,” their website states.
According to the World Health Organization, deaths from dementia have doubled since 2000. It’s now the fifth biggest killer worldwide.
The study is published in Neurology.
SWNS writer Mark Waghorn contributed to this report.