Actually, service dogs are trained to detect the beginnings of a seizure for those who are endangered by the severity of the seizure. Not all dogs are able to do so. The scientists, last I heard, thought the dogs were picking up on electrical signal abnormalities.
The owner is then able to get to a place of safety so they aren’t injured by the seizure - think in terms of being in the middle of traffic when a seizure starts, on a stairway, etc.
Is it to hard to understand the words, I don’t believe it! How do you train a dog outside of Pavlova. Use a divining rod!
It’s possible that a seizure is preceded by a chemical change that the dog can smell. I think dogs can detect diabetes because diabetics generate acetone or another ketone in their blood.