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.