@Summerose - how can there be criminal responsibility, if what happened was completely outside the driver's control? She had no idea she was going to have a seizure, and according to what I have read, it was her first seizure - so she had no idea it was going to happen.
Your analogy with the person with mental illness who stabs people would only be correct if she had known ahead of time that she was prone to seizures, and drove anyway.
Unless you can tell us how to prevent an entirely unforeseeable event - a practical measure that this woman could have taken, before getting behind the wheel, that would have prevented her having her first ever seizure, then unfortunately there is no crime here.
You could have your first ever seizure tomorrow - epilepsy can occur at all ages with no family history (30-40% of epilepsy is caused by genetic predisposition, and even then, both parents can have the predisposition but not have had any seizures, so they don't know they are genetically predisposed until their child is diagnosed with epilepsy and they have genetic testing) - and there is nothing you could do now that would prevent it. So will you still get behind the wheel tomorrow, and the day after, and the day after that?