My son has had nocturnal seizures for about 7 years or longer. He has not been medicated for 2.5 years right now due to a misdiagnosis. He has also had a sleep study for apnea. (which he does not have, he does have pmld, from rapid withdrawal of seizure meds, however).....
Ask his neuro or pede for a sleep study to make sure. Usually if there is apnea involved you would hear snoring, gasping or choking in sleep.
We ahve the same thing with eeg being normal between seizures(interictally), or showing some abnormal that was discounted. It makes it tough to figure things out.
How is he doing on topamax?