Scientists have assembled the most detailed chronology to date of the human brain’s long, slow slide into full-blown Alzheimer’s disease.
As part of an international research partnership known as the Dominantly Inherited Alzheimer’s Network (DIAN), scientists at Washington University and elsewhere evaluated a variety of pre-symptomatic markers of Alzheimer’s disease in 128 subjects from families genetically predisposed to develop the disorder. Individuals in the study have a 50 percent chance of inheriting one of three mutations that are certain to cause Alzheimer’s, often at an unusually young age.
Using medical histories of the subjects’ parents to estimate the age of the onset of symptoms for the study participants, the scientists assembled a timeline of changes in the brain leading to the memory loss and cognitive decline that characterizes Alzheimer’s. The earliest of these changes, a drop in spinal fluid levels of the key ingredient of Alzheimer’s brain plaques, can be detected 25 years before the anticipated age of onset.