[jacobrobbins]

it would seem likely that if they discover a physical mechanism at work in select individuals brains (electric waves followed by rhythmic waves of fluid) that the mechanism exists in some form in all individuals. I agree it does make for a clear follow up question: "could this mechanism be altered in some ways in people who experience sleep problems?"

[gshdg]

Or even "could this mechanism work differently in people who are unusually easy sleepers / deep sleepers vs. the general population?"