Just a curiosity, have you checked his anal glands? My Min Pin, Jezzy, will do that sometimes. She isn't a scooter, so when she starts acting like this, I know it is time to express her anal glands. May not be something as simple as this, but it would be nice if it wasn't seizures for you and your little guy. Best wishes!
Amy
Amy, Jezebelle, Keela, and Piper