A post from the blog Neurophilosophy:
“The research shows that people with Alzheimer’s, Parkinson’s and several other neurodegenerative conditions often experience sleep disturbances many decades before any symptoms appear, and that these disturbances are somehow linked to disruptions of the circadian rhythm. They include common sleeping difficulties such as insomnia, sleep apnoea, and daytime drowsiness, and some slightly more unusual ones. According to one small study published in 2011, for example, the early stages of Parkinson’s disease are characterised by alterations in the content of dreams, particularly the presence of animals and increased aggressiveness.”
Here is Dr. Greger on optimal sleep duration:
