I assume there must be researchers trying to do this electronically too (See - https://newsreleases.sandia.gov/seizure_sensor/ for example.). It might not be practical yet unfortunately though, and not sure if it would translate to animals.
Good luck in finding a solution though! I would assume something like an accelerometer on their collar might be able to detect shaking.
From the 2nd link:
> The worst part of epilepsy is never knowing when you’re going to have a seizure. The psychological impact of that uncertainty is overwhelming.
..which is one of the reasons I made this post.
Thanks for your input!