Researchers have long studied primary progressive aphasia, or PPA, "a form of cognitive impairment that involves a progressive loss of language function." Put simply, patients of PPA experience "degeneration in the parts of the brain that are responsible for speech and language."
Using a new type of positron emission topography (PET) scans that detect amyloids, researchers have found buildups of amyloid plaques on the side of the brain responsible for languages and communication.
Using PET scans, researchers at Northwestern Medicine have discovered the toxic buildup of amyloid protein is greater on the left side of the brain - the site of language processing - than on the right side in many individuals living with PPA.
This is an interesting development, as until now it was only possible to study the brain of an Alzheimer's' patient, for amyloid accumulation, after his or her death.
"By understanding where these proteins accumulate first and over time, we can better understand the course of the disease and where to target treatment," said Emily Rogalski, the lead study investigator and research associate professor at Northwestern's Cognitive Neurology and Alzheimer's Disease Center (CNADC). "It is important to determine what Alzheimer's looks like in PPA, because if it's caused by something else, there is no sense in giving a patient an Alzheimer's related drug, because it would be ineffective."
Researchers studied 32 patients with PPA and found that 19 had high amounts of amyloid. These patients were then compared to 22 people who had Alzheimer's memory dementia. "Those with the memory dementia had the same amount of amyloid on the left and right side of the brain." But the PPA patients exhibited higher buildups of amyloid plaques on the left side of the brain, the side associated with language and communication.
"This new technology is very exciting for Alzheimer's research," said Adam Martersteck, the first author and a graduate student in Northwestern's neuroscience program. "Not only can we tell if a person is likely or unlikely to have Alzheimer's disease causing their PPA, but we can see where it is in the brain. By understanding what the brain looks like in the beginning stages of Alzheimer's, we hope to be able to diagnose people earlier and with better accuracy."
The study has been published in the journal Annals of Neurology.
