Early Changes in Amyloid Could Offer Window into Future Alzheimer’s Disease
September 28, 2018
Research from the Park Aging Mind Lab suggests that evaluating changing amyloid levels in certain brain structures may offer an important early clue into who is on a trajectory toward Alzheimer’s.
Amyloid pathology is one of the earliest signs that an individual is at high risk for developing Alzheimer’s. Extensive evidence indicates that amyloid slowly builds up in the brain over the course of more than a decade before individuals develop dementia. The findings were published in Neurology, with Dr. Michelle Farrell as lead author, and demonstrated that early changes in amyloid in posterior cortical regions of the brain were associated with subtle declines in episodic memory — one’s memory for events, times and places that are autobiographical in nature. Declines in this type of memory are known to be one of the first symptoms of Alzheimer’s.
The research was conducted as part of the Dallas Lifespan Brain Study (DLBS) initiated and led by Dr. Denise Park, Director of Research, who was senior author on the study. Participants in the DLBS have had brain scans four years apart that assess whether the participants have amyloid deposits (a protein associated with Alzheimer’s) on their brains. Dr. Farrell used these data to relate changes in amyloid deposits to changes in memory function in cognitively normal adults ages 30 to 90. The study focused specifically on participants who were initially considered “amyloid negative” based on an amyloid PET scan. By following these participants over four years, the research team was able to detect increases in amyloid in specific
regions of the brain.
Interestingly, these early signs of posterior cortical amyloid accumulation were found to track with subtle declines in episodic memory. This early relationship between amyloid and memory was even found to be present in younger adults from age 30 to 59.
“These findings suggest that even the earliest signs of amyloid have observable consequences for memory, though not to the extent that these individuals would be considered to have dementia. It is only by following these individuals over time that we are able to observe these subtle shifts in amyloid and memory.”
Dr. Michelle Farrell
These and other findings are leading researchers to believe that we may be able to detect evidence for future AD many years before symptoms of cognitive decline become obvious. “This will become important as treatments for Alzheimer’s disease are developed. The hope is that we will be able to predict and stave off the disease early in the lifespan,” Dr. Park says.
In addition to Dr. Farrell, who earned her doctorate at UT Dallas prior to recently joining Harvard Medical School’s Athinoula A. Martinos Center for Biomedical Imaging at Massachusetts General Hospital, the other authors on the paper are Drs. Melissa Rundle, Micaela Chan, Gagan Wig, and graduate student Xi Chen. The study was supported by funding from the National Institute on Aging.
