Now this is very interesting. Seems to have no downside. Why not try it on everyone at risk? Anyone have a 40 Hz wave form file? https://www.independent.co.uk/news/science/alzheimers-protein-brain-sound-therapy-b2899318.html

Turns out you can get it all over youtube

Sounds like the gentle hum of a motor.

You should look into "binaural beats" or sometmes referred to as "audio entrainment".

Maybe its a placebo effect, but I put it on in the background on my headphones while listening to music and it helps me "lock in" at work and drown out distractions.

there are many different requencies you can set for different things, like sleeping, or relaxation. Try it out and see if it helps!