Others are saying it's a sleep disorder, a lack of deep sleep preventing the normal brain cleansing mechanisms from removing the byproducts of wakefulness. 

 I thought John's earlier interview with Patrick Holford was very good. Worth a watch if you are interested in or worried about dementia.
Very preventable for most people.

https://youtu.be/cXX4iMuwaVQ?si=Qbv3nsKHviXtXs6a 

 I’m a huge John Campbell fan. Putting it on rn, thanks