Alzheimer's: Trouble sleeping could affect memory later on, study finds People who have trouble sleeping may have memory problems later in life, a new study shows. Reuben Munoz / Los Angeles Times By Amina Khan, Los Angeles Times / For the Booster Shots blog February 14, 2012, 6:31 p.m. People who have trouble sleeping may be at higher risk of developing memory problems, new research shows. People who woke frequently in the night had a higher risk of developing Alzheimer's disease, according to work to be presented at the American Academy of Neurology meeting in New Orleans in April. Other research has shown a link between impaired sleep and multiple-personality disorder, as well as other forms of dissociation. And research in mice has shown that disrupted sleep can actually cause an increase in the buildup of amyloid plaque in the brain -- buildup that happens years before any outward symptoms of Alzheimer's occur. To see whether disrupted sleep affected humans, the researchers took 100 patients, half of whom had a family history of Alzheimer's, and monitored their sleep patterns for 14 days. They found that even though participants spent about eight hours in bed, on average, they spent only about 6.5 hours sleeping, because they woke up repeatedly during the night. Those who woke up more than five times an hour were much more likely to show evidence of amyloid plaque buildup in their brains. Those whose "sleep efficiency" -- the amount of actual sleep time divided by the time in bed -- was less than 85% were more likely to have preclinical Alzheimer's disease. It's unclear what the exact mechanisms underlying this link may be. But the study authors say it's a step toward investigating whether manipulating a person's sleeping habits could slow the progress of Alzheimer's. Follow me on Twitter @LAT_aminakhan.