I'm sorry, am I missing something here? Is Li Na dead right now? Is she in the hospital with complications due to this supposed concussion? If not, then this thread is stupid. Also, having the sensation of blanking out for a split second is not always a concussion. When you get hit hard enough, your eyes dilate for a split second and they stop working. You interpret this as a blanking out for a slip second. That's not the same as a concussion. A concussion is if your brain shifts hard enough in your skull to bruise itself against the wall of the skull.
If she had a concussion, she would have had other issues that would have been evident in her ability to have proper hand/eye coordination after the event. I don't think that happened.