is this seizures or behavorial fits

Hello i am 23 and have two kids my youngest was 4wks premature. and now at one he will be playing and then all of a sudden he will start jerking his head violently back and forth. and when i try to stop him i can't. there is a family history of gran mal seizures,febrile seizures, and myoclonic seizures. i had anywhere from ten to fifteen a day for most of my childhood.they finally subsided with medication. could my son be having myoclonic seizures?or a another type or are these just behavorial fits.