SCIENCE: Poor Sleep Linked to Alzheimer’s in Study of Brain Scans. “Brain images of adults with an average age of 76 found that those who said they slept less or poorly had increased build-up of beta-amyloid plaques, one of the hallmarks of Alzheimer’s, according to research published today in JAMA Neurology. None of those in the study had been diagnosed with the disease.” Which is cause and which is effect is unclear.