PET scans can be used to track the progression of Alzheimer's disease, the most common form of dementia, a new study out of the University of California-Berkeley is reporting.
In this study, the researchers recruited 53 adults and conducted positron emission tomography (PET) to look for potential signs of Alzheimer's. The sample set included five adults in the 20 to 26 age group, 33 in the 64 to 90 age group, and 15 in the 53 to 77 age group (the only group that was diagnosed with probable Alzheimer's).
The team used the stages of tau deposition, called Braak staging, that were compiled by German researchers who had analyzed the deceased brains of Alzheimer's patients as reference. Heiko and Eva Braak found six stages that can be used to determine the extent of tau development in relation to dementia in the brain. Tau and beta-amyloid are proteins that have been linked to the brain disease.
"Braak staging was developed through data obtained from autopsies, our study is the first to show the staging in people who are not only alive, but who have no signs of cognitive impairment," the principal investigator, Dr. William Jagust, a professor at UC Berkeley's School of Public Health, said in a press release. "This opens the door to the use of PET scans as a diagnostic and staging tool."
After examining the PET scans, the researchers were able to tie aging to the accumulation of tau in the medial temporal lobe. More accumulation in this region of the brain was tied to a greater decline in episodic memory.
"Tau is basically present in almost every aging brain," said Michael Schöll, a co-lead author, said. "Very few old people have no tau. In our case, it seems like the accumulation of tau in the medial temporal lobe was independent of amyloid and driven by age."
The researchers could not determine why the presence of tau in some cases did not lead to Alzheimer's.
The findings were published in the journal, Neuron.
