Now, studying spinal fluid samples and health data from 201 research participants at the Charles F. and Joanne Knight Alzheimer's Disease Research Center, scientists at Washington University School of Medicine in St. Louis have shown the markers are accurate predictors of Alzheimer's years before symptoms develop.
The researchers evaluated markers such as the buildup of amyloid plaques in the brain, newly visible thanks to an imaging agent developed in the last decade; levels of various proteins in the cerebrospinal fluid, such as the amyloid fragments that are the principal ingredient of brain plaques; and the ratios of one protein to another in the cerebrospinal fluid, such as different forms of the brain cell structural protein tau.
The markers were studied in volunteers whose ages ranged from 45 to 88. On average, the data available on study participants spanned four years, with the longest recorded over 7.5 years.
The researchers found that all of the markers were equally good at identifying subjects who were likely to develop cognitive problems and at predicting how soon they would become noticeably impaired.
Next, the scientists paired the biomarkers data with demographic information, testing to see if sex, age, race, education and other factors could improve their predictions.
Catherine Roe, PhD, research assistant professor of neurology, described the findings as providing more evidence that scientists can detect Alzheimer's disease years before memory loss and cognitive decline become apparent.
The study, supported in part by the National Institute on Aging, appears in Neurology.