Abnormal EEG's are not a typical part of the ADHD picture, but they do occur. As you've heard already, it can be difficult to pinpoint the nature of such behaviors as your son is displaying, chiefly due to the young age. Indeed, time will tell. Now, one possibility is to place your son on medication for a time, and see if the behavior improves, though it does seem very reasonable to hold treatment in abeyance for a time. Should Tourette Disorder be present, you'll see the development of other motor tics and some version of a verbal tic. At the moment, such involuntary movements are not evident. So, a diagnosis of Tourette is not sensible at this point.