My son (who is down s ) is nineteen years old and twice He has had what I call a tremor in his lower extremities. I noticed it happen after what appeared to be after a bowel movement , or maybe he thought he just had to go. It lasted a few minutes and now he seems to be alright. When should I seek medical care....or do you think this could be just a random event. Kyle is low functioning so I really can t ask him questions.