Try sound therapy for hearing loss treatment and prevention.
Listening to high frequency (more than 10,000 Hz) is supposed to "tone" the ears as well as our brain, leading to decreased need for sleep.
Mozart music is supposed to be rich in high frequencies.
Or you may just produce high frequency sounds using your computer with programs like Brain Wave Generator
which you can then play or record. You can download the program (click here)
for free. It has some built-in presets for high frequency, but you can up those to 16,000 or higher. Don't use your laptop speakers to listen to such, though. I think I burned one of mine doing that.