Fall / Winter 2025 | Research 9
“ Pathologists often couldn’ t tell just looking at the brain if this was a Parkinson’ s brain with a little Alzheimer’ s, or an Alzheimer’ s brain with a little Parkinson’ s,” said Kathleen Poston, MD, a professor of neurology at Stanford University.“ In other words, the brain of someone with neurodegenerative disease often had what scientists now call‘ mixed pathologies.’”
A Growing Understanding of Mixed Pathologies
Studying the brains of people during autopsy provided crucial information. But what the field really needed to advance was a tool to detect the disease while people were still living.
That tool came in 2023, with the validation of a biomarker test that can detect the presence of misfolded alpha-synuclein in brain and body cells. Investigators can now confirm the presence of this hallmark Parkinson’ s sign in living people, even years before symptoms develop. This breakthrough, made possible by an international coalition of scientists led by The Michael J. Fox Foundation, ignited a wave of new research.
Within a year, investigators affiliated with the Alzheimer’ s Disease Neuroimaging Initiative used the test, called the alphasynuclein seed amplification assay( aSyn- SAA), to analyze samples from participants