1) There is a researcher named Reuben Sandyk that you might be interested in. Among other things, he has 500 or so papers on Medline on a wide variety of "fringe" issues related to PD. But, in particular, if you google him you will come up with a nice patent drawing showing how to build a rather simple assembly to do this sort of thing.

2) I have wondered about the use of old style stereo speakers (the old 8-ohm type, not the newer self-powered ones) for this. You have a modulated current going into a coil creating a fluctuating field that moves the magnet at the apex of the cone. If you lie down with a speaker to either side of your head an put on a Mozart piece, I wonder what happens in the brain? And you can regulate the strength of the field by the distance between the speakers.

3) A really sharp tech should be able to tinker with a cell phone..... But that exceeds my white rat risk limit