At the same time, we have been stumped by his inability to actually use his hands for more functional purposes like grasping and holding toys. His hands almost seem to get in the way - he always wants them near him; they are always up by his face, and his shoulders are always held close to his body (which gets in the way of eating, tummy time, games or pretty much any activity that involves using his hands). It also causes him to hunch his shoulders, which is not good for his back or lungs.
Today we realized there is a new dimension to his hand movements. He seems physically unable to move them except in unison! In other words, when one hand moves a certain way, so does the other. We've noticed he tends to always reach with both hands, and when one fist grips our finger, the other goes through the same gripping motion even though it has nothing to hold on the other side. But it is not just gripping...today we took photos of his "gestures" and every movement is symmetrical...
His feet do it too! If we touch one foot and it flexes a certain way in response, so does the other one!
In an attempt to find the medical term for this behavior, google and pubmed were helpful and so was youtube...it's called "Congenital Mirror Movements" aka bimanual synkinesis. We have found out some of the implications (writing, typing, climbing ropes, piano--um, difficult to say the least, even if he was otherwise completely healthy), and some of the underlying causes (disorders of the corpus collosum, disorders of the pituitary, disorders of the cervical spine, random syndromes - all of which could apply to Mason). He may even have a more generalized synkinesis (in his face, a smile can evoke squinting of both eyes...which is intractably adorable!)