Head shaking

Hi. I have a 3 year old child who has Hydrocephalus,Holoprosencephaly,and C-acc. He shakes his head as if saying know most of the time . I have noticed if he is focused on something on the TV or something else that catches his attention he will stop doing this also. Does anyone else have a child that does this and know what is causing it? Any suggestions would me very much appreciated. Thanks,Terri Whitney

your child is probably stimming, playing with his vision.