I can understand how to train a dog if I know “Ok this person is having a seizure in X minutes, time to cue the dog”
But when you don’t know? Would you need an existing trained dog to bootstrap with? Who trained the first one?
We have a dog that could do it. She could warn us about my partner’s seizures and fainting a few minutes before it happened. She could fetch help and apply pressure to the abdomen. (I say could because my partner had surgery a year ago and hasn’t had any seizures or fainting since then.)
I definitely noticed a change in my partner before seizures (but not fainting). The dog alerted on me once during a moment of high anxiety. I wouldn’t begin to argue WHAT the dog is actually reacting to, but the training methods people are using seem to work.
The paper goes into a bit of detail on training, but it's a fair and interesting point: How do they get the seizure scent? I guess you could maybe take a sample just after a seizure, or a second person could do it if they were present and prepared to take it.
I doubt that they train dogs like "Steve's having a seizure. Good! Get that dog here."
I imagine that you do a preliminary training with faked seizures to get responses right and then hope (meaning: Train under real conditions) that the dog will react on a real seizure as well.