New research led by scientists at University of California, Berkeley shows for the first time that PET scans can track the progressive stages of Alzheimer’s disease in cognitively normal adults, a key advance in the early diagnosis and staging of the neurodegenerative disorder.
In the process, the scientists also obtained important clues about two Alzheimer’s-linked proteins — tau and beta-amyloid — and how they relate to each other.
The findings, published March 2 in the journal Neuron, come from positron emission tomography (PET) of 53 adults. Five were young adults aged 20-26, 33 were cognitively healthy adults aged 64-90 and 15 were patients aged 53-77 who had been diagnosed with probable Alzheimer’s dementia.
The stages of tau deposition were established by German researchers Heiko and Eva Braak through post-mortem analysis of the brains of suspected Alzheimer’s patients.
“Braak staging was developed through data obtained from autopsies, but our study is the first to show the staging in people who are not only alive, but who have no signs of cognitive impairment,” said study principal investigator Dr. William Jagust, a professor at UC Berkeley’s School of Public Health and at the Helen Wills Neuroscience Institute and a faculty scientist at the Lawrence Berkeley National Laboratory. “This opens the door to the use of PET scans as a diagnostic and staging tool.”
PET scans are used to detect early signs of disease by looking at cellular-level changes in organs and tissue. The results of the scans in this study paralleled Braak neuropathological stages, which range from one to six, describing the degree of tau protein accumulation in the brain.
Dr. Jagust worked with study co-lead authors Dr. Michael Schöll, a visiting scholar, and Dr. Samuel Lockhart, a postdoctoral fellow, both at UC Berkeley’s Helen Wills Neuroscience Institute.