==One possible change== 

 You have added some great additions to this stub. My one suggestion is to change this line: "In the two videos cited, both patients were asked to take a breath and say "Ahh" as long as they can." I would references the actual people/organizations in charge of the video to give this article more of a professional feel. Also, it will help other people doing research trace back to these people faster and see other works they have done. Nevertheless, great start!