3xmama--
You might be interested in this book:
http://www.oepf.org/product/reflexes-learning-behavior
and/or on what you can find by googling "Sally Goddard vestibular." I am no expert and am not pushing this at all--but I am newly investigating this area myself so I wanted to pass along the info. My understanding (not yet verified to my satisfaction) is that, for kids who have vestibular issues, OT can be frustrating (and might not work terribly well) until you get the vestibular stuff dealt with.