Functional imaging of the brain at rest may be a noninvasive way of detecting the early onset of Alzheimer's disease, according to a new study published online in JAMA Neurology.
In the study, as reported in an article in AuntMinnie.com, Liang Wang, M.D., of Washington University in St. Louis, and colleagues analyzed samples of spinal fluid taken over several years from older, cognitively normal volunteers from the Charles F. and Joanne Knight Alzheimer's Disease Research Center at the university in order to assess changes in beta amyloid and tau protein. Previous research has demonstrated that Alzheimer's patients accumulate both beta amyloid and tau protein before the onset of Alzheimer's, and differing levels of both are considered to be reliable indicators of preclinical Alzheimer's disease.
At the same time, the volunteers also underwent MRI scans. During these scans, they were asked to concentrate on a visual cross hair, remain still and not fall asleep, and researchers, using this resting state MRI, were able to track the blood flow through different brain regions.
Earlier studies have shown that a set of connections between the different regions of the brain called the brain's default mode network--as well as other brain networks--is damaged by Alzheimer's disease. In this study the researchers used data to assess the integrity of the brain's default mode network and determined that the damage to the network occurred at about the same time that beta-amyloid deposits started increasing and tau levels started to decrease fluid. In addition the part of the default node network most harmed by the onset of Alzheimer's was the part associated with memory.
The authors concluded that the effect of decreased beta amyloid and increased tau on the default mode networks can give researchers insight "into the early pathogenesis" of Alzheimer's.
Deposits of amyloid beta, an abnormal protein associated with the development of Alzheimer's disease, can be detected in the brain decades before the onset of the disease, according to results of a study published earlier this year in the journal Lancet Neurology.
Scientists at Stanford University believe that results from some fMRI scans may have been unintentionally distorted, and may put into question the conclusions of hundreds of scholarly studies that have relied on the imaging technique.