Wednesday, December 07, 1994

Trying to understand what Martin Schwartz is saying

To Martin Schwartz

> I stated:
>
> It seems to me that what you are saying is: that's where sounds are produced,
> and certain conditions in terms of tension must be present for this production
> to be enabled. If the right conditions are not present then the sound
> will not come out or will repeat or whatever...i.e. stuttering.
>
> IS THIS A FAIR, ALBEIT OVERSIMPLIFIED, CHARACTERIZATION OF YOUR
> FUNDAMENTAL ARGUMENT?

Tuesday, December 06, 1994

Is stuttering a "vocal cord" problem?

Post directed to Martin Schwartz

Frankly, I must still be missing something. I have been waiting for "the
other shoe to drop" in terms of compelling evidence about cause and effect
(the vocal folds being the cause), but, in spite of your well thought out
separation of different types of tension at the folds and how different
combinations could be associated with different types of stuttering, I still
fail to see why that should be the CAUSE.

It seems to me that what you are saying is: that's where sounds are produced,
and certain conditions in terms of tension must be present for this production
to be enabled. If the right conditions are not present then the sound
will not come out or will repeat or whatever...i.e. stuttering.

I am biased against this view in a number of ways. The vocal chords are
the site for sound production but not for SPEECH production... The
brain is where the control commands for speech originate and that's where
I think they get screwed up, probably by the very same set of tensions you
think impair the vocal folds. My bias comes from a background in control theory
and my background as a stutterer.

>From a law of parsimony point of view it seems to me that the very sensitive
coordination of control commands required to set speech in motion is a much
more likely site of vulnerability than the much more ancient and sturdy vocal
chords. From a stutterer's point of view I must also say that I simply do
NOT feel blocked at the throat, I never have, and at this point in my life,
I have very little tension in any part of my speech apparatus. Now, I realize
how unreliable subjective "feelings" are , which is why I called this
a "bias" as opposed to "evidence".

Speaking of evidence, what do you think of the evidence cited by Woody,
which implies a speech disorder as opposed to a "sound apparatus" disorder?
This, of course, reinforces my original bias, but I hadn't been aware
of it. In particular I am intreagued by the problems in sign language.

Of course my lack of agreement in no way implies lack of appreciation
in your efforts at unraveling this nasty problem and at pushing some
sense into thick heads like mine.

Monday, November 07, 1994

The need for sensory feedback

What follows is the first of several posts centered on a model of stuttering proposed by Martin F. Schwartz, according to which the root cause of stuttering is at the level of the vocal folds.

This was written in reaction to one of Schwartz's ideas on selectively destroying sensory laryngeal nerves...


> This seems to me like a very strong assumption about what "triggers stuttering".
> Isn't sensory feedback needed to be able to talk at all? I guess in principle
> one could go "open loop" (in the control jargon) after having learned... but
> how long would that last? Is there any illness that simulates that and
> which we might look at?

An answer by Bob Volin mentioned how speaking adults who have profound hearing loss eventually see a degradation in their speech. This and other similar phenomena confirmed my idea that feedback is not a mechanism to be easily dismissed. Eliminating feedback for therapeutic purposes was extremely suspect to me.

Friday, November 04, 1994

Frequency distribution of stuttering severity

I asked about the statistics of stuttering severity. The answer by Woody Starkweather (Temple University) is that, as for "neary all" disorder severities the distribution is right-skewed with many mild stutteres and few severe ones.

A single number index of stuttering severity has been developed. It's called PDST (Percent Disfluent Speech Time) and it includes "possibly most" elements of stuttering severity. It is computed by dividing the sum of the times of stuttering behavior durations by the total duration of speech time.

Monday, October 31, 1994

Some initial questions

>I understand there are different types of stuttering, and I am not sure about
>the exact terminologies, but one might, for instance, start stuttering after a
>head injury (adult onset?). Let's just talk about "mild" vs "severe"
>stuttering.

Answers:
1. Acquired stuttering (sudden onset in adulthood) is rare and typically due to some brain injury.
2. The usual "developmental stuttering" is a childhood disorder that usually manifests itself between 2 and 9 years of age.

>Do these (mild and severe stuttering) have essentially the same etiology, with >severity being caused by additional layers of learned "bad habits" ? Or is there >something fundamentally different?

Answers:
1.Basically we do not yet know the etiology of stuttering.
2.However mild and severe stuttering appear to differ considerably in how they can be treated and how they respond to treatment.

>As a mild stutterer I have had the tendency to assume that the techniques I
>have used successfully to control my stutter are equally applicable to severe
>stuttering. Is this a good assumption? Is there value in questioning it?

Answer:
Effectiveness of techniques depends more on actual speech behaviors than on stuttering severity