Some owners can sense a seizure coming on in their dogs (just as some dogs can sense it coming on in their owners). They see an aura of sorts, also called a prodrome — a pre-symptom symptom, if you will, wherein the dog may act upset and anxious and seek attention from his owner or, conversely, withdraw and hide.
The seizure itself — the tonic-clonic phase — begins with stiffening of the muscles. The dog will often fall to his side with his legs stretched out and his head thrown back. At that stage, once the seizure has begun, the dog is no longer fully conscious even though his eyes might still remain open. Some dogs vocalize during the seizure, or their face twitches. Often, they’ll drool a lot — or urinate or defecate.
All of that is the tonic part, which is very brief, lasting fewer than 30 seconds. Then the seizure enters the clonic part of the phase. The dog’s movements become rhythmic. There can be a chomping of the jaws and a jerking or running movement of the limbs. Often he will stop breathing, and his tongue will turn blue.
Afterwards, when the dog comes out of the seizure, he will very often feel disoriented — to the point of seeming blind while bumping into things. Dylan Grams’s Boston terrier, Lou, goes through that after a seizure. “He’s usually pretty confused,” Mr. Grams says. “He’s trying to get his bearings. It takes about five or 10 minutes for him to come back to his normal self.” For some dogs, fully getting back to themselves can take two to three hours.