Re: 15 month just diagnosed with possible mild CP from pediatrician
It sounds to me like he could have associated reactions. This is where the child uses tone to make another action easier. In my sons case its when he's sat in his chair and draws or eats, the hand he's not using gets tight and pulls in toward his body. Running is an extremly difficult skill for a child with CP, so to see another part of his body react would fit. Again throwing, any skill like this is difficult, reactions can quite often be seen. Google it.
General rule - if the muscle is tight its high tone, if its loose and floppy is low tone.
Will the neurologist do an MRI or EEG? From this is there any visable damage? Then ask what they think this all means, taking into account the physical manafestations being seen and whether or not there are any signs in his brain of problems.
But to me you need a good Occupational therapist and Physical therapist in place ASAP, the sooner you start, the sooner you will see the physical problems reduced.