The main plot of my story is my main character being lost in modern day New York City without being able to see or speak, having to rely on strangers to get back home. So far, I've given him a Grade IIIb concussion but that will only make his speech incoherent and I'm trying to get him unable to speak at all. Will a vocal cord hemorrhage cause that? And if, after getting a vocal hemorrhage, my character keeps doing whatever caused it, will he end up coughing up blood as well?
I read the "Concussion" and "Dementia pugilistica" articles on Wikipedia. I used Google to search for "poisons that affect your voice" and "trauma that affects vocal cords" and found http://www.entnet.org/HealthInformation/commonvoiceproblems.cfm and http://www.netwellness.org/healthtopics/ent/voice.cfm. I also asked this question on Yahoo!Answers, but I haven't gotten anything useful yet.
Any other information you can give me on vocal cord damage (not permanent), severe concussions (specifically how long amnesia from a concussion can last), or New York City (people and places) would be great as well. Thanks in advance!