Hi,
How is your son? How was the test results? Do you have a history of seizures in your family? Twitching and jerking highly suggest neurological issues. It is best that further evaluation be done to rule this out.Complete physical and neurological issues and the test results will help determine the underlying cause. Do keep us posted with the results. Take care and best regards.
If your son seems to have such problem then there might be some kind of warning signal before the jerks or abnormal movements occur.Its called AURA which is felt as Tensed feeling,visual disturbance,smelling a bad odor,hearing strange noises.So ask your son for any feeling felt differently like this when everything is settled down.Donot panic him as most of the people confusion and blankly stares out and are unaware of the situations around.Let him try to remember what has happened.You may generally test his attention to ask him what is the time now,day today,dates ,year,city,address of your home ,your name or whatever seems to be related like this.By this you understand his attentiveness.Ask him to interpret the situation,describe it in small details.This will certainly give you more clues and development of his condition.Tell me if you face any other complication.
As the symptoms suggest me it could be Childhood Absence Epilepsy a nervous disorder that is very commonly seen in children.Confirmation of the disease involves a lot of history because a lot of brain disorders also appear in the same way.The thing you have mentioned about your son is only one symptom.Get the full history like previous attack like this,time and duration of attack,parts of the body involved, behavioral changes after and before attack,sleep cycle details,sensation of the body,medicines being used for anything or present problem,language skills and change in its phonation or anything else are very important to make a diagnosis.
Tourettes syndrome involves change in articulation and pronunciation of words and tics with behavioral changes.There is nothing much to worry about your son as there are best treatment strategies for a condition like this.I can help you,get me more information about your son.