New type of dementia discovered

Scientists have identified a new form of dementia that has long been misdiagnosed as Alzheimer’s—a confusion that may have hampered efforts to find treatments for that disease. The researchers say that, based on autopsy studies, about 20 to 50 percent of people ages 80 and over have brain changes associated with the newfound neurodegenerative condition, called LATE. Scientists believe that about 20 percent of older people diagnosed with Alzheimer’s would be better classified as having LATE, reports The Times (U.K.), and that another 30 percent may have both diseases. While Alzheimer’s and LATE have similar symptoms—including memory loss and cognitive decline—the conditions are caused by different misbehaving brain proteins, and LATE progresses much more slowly. That “might help explain why so many past Alzheimer’s drugs have failed in clinical trials,” says lead author Peter Nelson from the University of Kentucky. Scientists have long wondered about the existence of another Alzheimer’s-like disease, after discovering through autopsies that many people who die in advanced age have dementia symptoms but don’t have two hallmarks of Alzheimer’s—the protein amyloid beta, which forms plaques between nerve cells in the brain, and tau, which grows tangles inside brain cells. There are currently no tests to identify LATE. Still, the discovery of the disease could help refine research aimed at early identification and treatment of neurodegenerative conditions. ■