8yr old with spikes on eeg, jerking in sleep,prozac

my 10yr old was put on prozac in december 2007. about a week later he fell asleep on my bed and i noticed a hard jerk after he had already had the regular jerking when you first fall asleep. i told his pediatrician and she said she didn't think it was related to the prozac which is on for anxiety and behavior problems in school. about 5 weeks(after being on prozac for about 7 mos) ago he fell asleep on my mom's couch and we saw him jerk different parts of his body for about 30  minutes.  it was totally abnormal movements.  i saw the pediatrician and she did not think related to prozac but i did so we tapered him off. she ordered an eeg for the next week..he was still on half dosage of prozac which showed no seizure activity but did show what she said were spikes and she ordered an mri which he is having tomorrow. the pediatrician said that this could mean he will have seizures in the future and she wants him to see a neurologist also.  i am very worried.....he is still doing the jerking and twitching in his sleep....most of it is right after he goes to sleep and i have watched for an hour and he is still doing it. i saw his eyes open a few time but he went right back to sleep.  have you ever heard of this happening with prozac?  He's never had a seizure.  his birth mother could have been on drugs when she was pregnant with him...could this have anything to do with this?  how long will prozac stay in his system after stopping....it's been about 4 weeks.  thanks for any help you can give me.