He had a detailed hearing test at birth & then at 3 weeks old as he spent a week in NNU. They were both clear. He's been smiling since 4 weeks old, makes brilliant eye contact & can track objects. He can definitely hear. However I've noticed if I make a noise to the right of him he turns, the left side not at all. I'm not sure if 12 weeks is a bit early in general or the fact he's doing it on one side & not the other is a cause for concern rather than him not doing it at all on either side. Does anyone have any experience of anything similar?