Here is a head injury law firm that does WC http://www.heinlegal.com/workers-com...brain-injuries

and http://www.cmhlawfirm.com/

There are plenty in MO who do WC and TBI but I did not find any that mentioned concussion or mTBI.

I googled missouri, head injury attorney and Work comp and it appears that many personal injury attorneys also do Work Comp cases.

You will need to do some direct calls to find one who understands concussions. It takes special knowledge of the subtleties of concussion and the web sites don't mention concussion as an issue except for Hein and Hennesey ( a former Registered Nurse, maybe a better choice)