Difference between MTD and SD?

Can someone explain to me how doctors can differentiate
between MTD and SD in their diagnosis?

I've heard that SD has a neurological origin while MTD
is based on learned misuse of the vocal muscles. But
my understanding is that they sound very similar. In
my experience, the doctors I've seen have not done any
neurological tests (their diagnosis has been based
purely on what they can hear and on looking at the cords
with a scope).

Just out of curiosity, can any of you visually notice
more muscle movement in your throat area when you
speak than "normal" sounding people who do not have SD?
I've spent some time observing others when they speak;
any muscle movement in their throat area is barely
visible, if at all. On the other hand, I can definitely
visually see more muscle movement in my throat area.

You are correct in saying that SD is a neurological disorder. It is actually a movement disorder where there is dystonia present in the vocal cords/larynx. Sometimes it is helpful to think of SD (spasmodic dysphonia) being the description of the voice that results from the disorder, which is laryngeal dystonia.

In contrast MTD (muscle tension dysphonia) is a voice that can result from vocal abuse/misuse and responds well to voice therapy, where the 'bad habits' are unlearned. SD does not respond to voice therapy in general, although it can be of limited use.

Both AD/SD and MTD can sound similar (a tight, strained, strangled voice) but an experienced doctor or speech pathologist can tell the difference - we had it explained at the NSDA Symposium in Scottsdale, AZ back in March this year that SD has typical breaks in pitch and interruptions on certain word combinations, whereas the MTD voice has a more constant and stable straining quality.

There isn't any neurological test for SD - the best diagnostic tool is the ear of a trained listener.

Your question about the apparent muscle movement visible in SD patients ... my take on this is that it is just the result of the extreme effort needed to force out the voice in a case of average/severe SD.

"Both AD/SD and MTD can sound similar (a tight, strained, strangled voice)but an experienced doctor or speech pathologist can tell the difference - we had it explained at the NSDA Symposium in Scottsdale, AZ back in March this year that SD has typical breaks in pitch and interruptions on certain word combinations, whereas the MTD voice has a more constant and stable straining quality."

.... You may have just explained something to me that I couldn't figure out before.... This winter, when I mailed that research article I found on SD to my speech path. it specifically mentioned this -that one of the determining factors is that SD has breaks, and MTD does not. It also talked about pitch irregularities etc. and basically described my voice to the letter pretty much, including things the initial assessment she did showed. (before we knew anything about anything, or had made any conclusions) ... I THOUGHT that it would 'prove' to her that yes, she was right all along, the spasms ARE neurologically related, which she has always asserted, except when I approach her specifically about dystonia. ('course, I also thought she would be not pregnant thei stime when I approached her with it,and that wasn't the case)

.... Anyways, I thought that this article would show to her that yes, this was, in fact, SD, and not MTD, because I was assuming she knew enough about both conditions to know the differences and stuff... especially after we determined that speech therapy directed at the 'over contraction of the muscles' as she put it, and the lack of coordination and all that stuff, (rather than my other communication problems) not only didn't help, but MADE THINGS WORSE.

Especially after the one doctor who does believe that it's SD (who has a pretty good background in neurological stuff, but isn't in a position to give me a diagnosis of SD) said that after reading that article she was UTTERLY CONVINCED that yes, I do have SD, and that I should show this article to my speech path., I thought this meant that it would have the desired effect.

...Now I'm realizing (also based on the response I got from my speech path. which was basically "I don't feel confident in my own abilities with something so uncommon") that her response, which was really confusing and contradictory in the first place, mithg be because she ISN'T experienced in this area. I mean, she knows a lot of things about a lot of speech, language, and communication things, and she is pretty experienced with a lot of things now too, certainly enough so that I would think she would've lost her self-consciousness about her own ability to make decisions etc. (hell, I've known her for 5 years now) but maybe she hasn't had much experience or exposure to dystonia stuff, I don't know.

She always seemed to know pretty much everything, or at least know where to look if she didn't know, and pretty open to admitting she didn't know, and looking things up, but... maybe she just hasn't had much experience with dystonia. I think the majority of her patients are stroke patients, or otherwise brain injured, but I do know she's had a number of other people with different situations too.

I don't understand what your statement about "I have yet to hear of an MTD patient who later self-diagnosed as SD." has to do with backing up your claim; wouldn't it make more sense that the REASOn no MTD patient that you know of has later gotten a diagnosis of SD suggest that they in fact HAVE MTD, and not SD, and therefore these are different things?

In my opinion it's a mistake, and too simplistic, to use 'spasmodic dysphonia' as a synonym for any kind of strained strangled voice.

Dr Thomas Murry, University of Pittsburgh, who spoke at the Scottsdale symposium, said that although there is a role for voice therapy in dealing with SD, on its own it is a "very poor band aid". That's a direct quotation from one of the leading experts in the speech pathology field.

On the other hand, voice therapy is the recommended method of dealing with MTD. There is a clear difference.

In my opinion, if you really have SD, and I'm defining that as the voice that results from laryngeal dystonia (so a neurological movement disorder) you will just be spinning your wheels if you classify it as a strained voice and only rely on voice therapy. To my mind, if you completely resolve a strained/strangled voice this way, then it's a good indication you didn't have SD in the first place.

There may be some use for speech therapy in SD (which there obviously is), but it's useless for treating the underlying cause or even effects. (ie. spasms, as opposed to the compensatory strategies one may use to speak around the spasms/etc.)

Of course, I have a strong opinion on this matter sicne speech therapy not only didn't help me, but MADE THINGS WORSE.