Hey Robert,
I’m not an expert on ADHD, but I’d be happy to help you collect/analyse some data! There are definitely many aspects of EEG that might be worth tracking, but there’s not a lot of (accessible) tools out there to properly analyse it. As for looking at the data: there’s a wealth of possibilities to look at the raw data. As for tracking: At the moment your best option is to have someone write a small script to analyze single recordings (raw data) to spit out a few numbers that you can then put in an Excel sheet.
When considering buying a device there are tons of options. At the moment my pick is op-innovations.com, but I’m also anxiously waiting for the MUSE to ship.
Feel free to ask here, if you need me to help with a particular question!
Best,
Martin