Kepprage or behavioral problems? (kinda long)

Hello, Sorry this is a bit long.I'm searching for insight into distinguishing "Kepprage" from behavioral problems. My 4 year old son was diagnosed with epilepsy (idopathic and no diagnosis of type despite multiple EEGs) last August. He's been on Keppra 2ML 2x/day, which has successfully controlled the tonic-clonic seizures. He has a history of (relatively mild) oppositional defiance and aggression, mostly with myself and my husband. In the past couple months his aggression toward us has escallated dramatically. He now scratches and hits wildly, purposefully trying to hurt us, mostly when frustrated and being defiant, but occassionaly it seems out of nowhere or simply as a result of being "wound up." Just saw his neuro today and she thinks it's behavioral, not the Keppra, because of 1. his history, 2. that it only happens with us - he's never attacked anyone else the way he does with us, and 3. the behavior comes on and subsides suddenly - he demonstrated in her office today by attacking me when I tried to get him to let her examine him, so I guess it was good she got a first hand look at what he's been doing. For any of you out there who've had experience with Kepprage, can you tell me what it was/is like for your child? Does it happen across the board - with you and at school, with babysitters/grandparents, etc? Does it start and stop suddenly or gradually? Our neuro would like us to stay on Keppra and I would too, since we know it's working to stop the seizures. We have seen a social worker and had psychlogical evals but since their plans (consistent consequences, etc) aren't working, they think it's the med. The neuro thinks it's more likely a behavior problem that hasn't been appropriately diagnosed yet. I am very confused and want to get my son the right help!! Thank you for any insight anyone can offer. Cynthia