Re: odd shaking - partial seizure?
This can happen and is thought to be familial in nature. A friend's boxer did this and after asking her breeder about it, it was found that the dog's uncle did it as well as his father.
If you do a search on Ideopathic Head Tremors, and pay attention to specific results in Dobermans and English Bulldogs, you'll likely find similar accounts of this happening. The biggest thing is that you want to make sure that it's not a true seizure. It has been my observation that the biggest difference between the two is that dogs with Ideopathic Head Tremors are 100% completely aware of their surroundings when they happen. They respond when their name is called and respond to commands.
There is some thought that these tremors can be caused by certain food additives or colors (think raw hide, colored cheapo dog biscuits, etc) or allergy. Some have found success in giving the dog something to focus on once a tremor begins (for example: wiping a bit of peanut butter on the roof of the dog's mouth).
Many dogs who have this condition live long lives despite the occasional tremor, but again, you may want to check with the vet to make sure that what you're seeing is not seizure related.
Hope this helps.