What Causes Involuntary Movements In Upper Body?

My son has been seen by 3 ped. neurologist. He has had 2 EEGs and 1 MRI. All read normal. His new neurologist is testing him for neuroblastoma and she is repeating EEG this time for 24 hours. He was put on seizure meds on Feb 4th and his eps had decreased. They did last 1-2 hours, 2-3 times a day (each individual eps was 1-5 mins at a time). With meds they are down to 5-10 mins, 1-2 a day and he has went some days with no eps. He has involuntary movements of his upper body. I am pasting in a link to his lastest eps. WWW.WWWW.WW This started at 14 months and my son is now 19 months. I feel that he does have a movement disorder.