This is exactly what my neuro is doing. I had an EEG 3.5 years ago that showed nothing so I wrote it off as me having no problem. My symptoms have continued to get worse. I got a new neuro doc and she thinks it's seizures and is trying meds to see if symptoms lessen or go away.Is there any way you can videotape your nocturnal seizures? A detailed description of your symptoms (and perhaps a video) can help the doc to make the diagnosis in the absence of a positive EEG.
Many people with epilepsy will have EEGs that are normal, so in those instances neurologists make the diagnosis based on the symptoms alone. If the neuro isn't sure, he might recommend trying a small dose of anti-seizure medication to see if it helps.