Researchers had the participants sleep while wearing headphones and monitored their brain activity. "But a good night's sleep is something you want to be striving for anyway".
"Getting a good night's sleep is important for a range of different health reasons". The sounds usually didn't wake the people up but kept them from getting any slow-wave sleep. On one night, when they drifted into deep (known as slow-wave) sleep, the headphones played a tone at increasing volume until they reverted to lighter sleep. And once a person has the disease, disruptions in the brain may make it hard to sleep.
Among those who showed a response to the disruption, the team found on average levels of beta amyloid were about 10% higher when the beeps were played. "All we can really say is that bad sleep increases levels of some proteins that are associated with Alzheimer's disease", she said. Specifically, "this suggests that there's something special about deep, slow-wave sleep", says Kristine Yaffe, a neurologist and psychiatrist at the University of California, San Francisco who was not involved in the study.
But data collected by the participants at home revealed an effect. "I think that may lead to chronically elevated amyloid levels, which animal studies have shown lead to increased risk of amyloid plaques and Alzheimer's".
"Also, when we looked at their home sleep, the worse their sleep, the more their tau increased", Ju said.
Sleep helps to cleanse neurotoxins from the brain - the type that can lead to dementia or Alzheimer's. The concern is for chronic sleep deprivation. Thus, the researches came to the conclusion that poor quality of sleep, daytime sleepiness and sleep problems are connected to increase this disease.
While the study size was small, experts say the research is an exciting step in unpicking the early stages of Alzheimer's disease.
The basic finding is that the more disturbance of sleep that people reported, the more likely that they were going to have pathology in their spinal fluid thats related to Alzheimers disease, said Stephen Rao, PhD of Cleveland Clinic, who did not participate in the study. But, she noted, it was not clear whether helping people to sleep better could prevent or treat Alzheimer's disease.