Spasmodic dysphonia (SD), a focal form of dystonia, is a neurological voice disorder that involves involuntary "spasms" of the vocal cords causing interruptions of speech and affecting the voice quality. SD can cause the voice to break up or to have a tight, strained, or strangled quality.
For reasons that seem to be unknown, the brain starts telling the nervous system (in a specific or "focused" area) and it's muscles - in our cases, the vocal cord area (for spasmodic dysphonia) - to tighten up. Folks with AD/SD find their vocal cord muscles tighten in the "closed" position giving them a strangled or tight voice. They have to use more air volume/force to make sounds. Sentences become pretty impossible for many.
Those with AB/SD find their vocal cord muscles spasm in the "open" position, giving them a very breathy and weak voice. There is nothing for the expelled air to "vibrate" so it rushes out without much sound being made.
So this "focal" dystonia (in the case of the vocal cord muscles, it's called a dysphonia) happens in the throat. There are, of course, other focal dystonias in other parts of the body. I assume the brain/nervous system/muscle "miscommunication" happens similarly in those areas (e.g. writer's cramp).
Of course David's answer is correct and there are more technical descriptions that can be given. Hope this helps. John
Modified by JOHN S. BEEMAN at Thu, Jan 01, 2004, 13:41:59
Hi Cathy:
I noticed you said that a doctor told you that you "overused
your voice". Is he/she suggesting that this was a cause of the
SD? (because, as I'm sure you've found out from the replies to your original post, SD is not caused by overuse of the voice). Was the doctor an ENT? Also, do you have a confirmed diagnosis as to which type of SD you have? I assume you know that there are 2 basic types: AB and AD.As an oversimplification, AB is where the vocal folds are open too much, and AD is where they are too closed Which do you have? This ultimately affects what type of speech therapy you would get. I have a mild form of AB and have benefited from speech therapy. I have not had botox thus far. What has the speech therapist done to try to help you? If you have AB, I can maybe share some of what I've learned from mine. There is also muscle tension dysphonia. Let me know how it's going. Best of luck.
Keith
AB/SD
Pennsylvania
Modified by Moderator-DB at Wed, Jan 07, 2004, 13:10:11
Keith,
Thanks for the response. I guess I have AD SD. I was never told but I know that my vocal cords shut when I try to speak. I went to speach therapy and they taught me how to push the air out before speaking.
Cathy - after I posted my note to your question (on the SD-BBS), I found my Oct. 2003 edition of the SD Newsletter. It contains some really great explanations about SD and various treatments. I suspect if you contact the NSDA you can get a copy. Good luck. John
