The researchers had shown that fragmented sleep - which is sleep interrupted by frequent awakenings or arousals — was linked with an increased risk of dementia and cognitive decline, Lim told Live Science. "However, there were gaps in what we knew about underlying brain changes that may link sleep fragmentation with these neurological outcomes," he said. In the new study, the researchers looked at the brains of 315 people who underwent autopsies after they died. The people were 90 years old, on average, when they died, and 70 percent were women. At some point before they died, the people in...