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From: Darrell Dodge
Date: 10/10/02
Time: 1:55:26 PM
Remote Name: 134.29.30.25
I appreciated your article very much because of its focus on the fact that stuttering therapy does work for many people. The efficacy of stuttering therapy is continually challenged, however, by the inability of a sizable percentage of stutterers to benefit, and somewhat less by the persistence of stuttering even for people who have received substantial and (as you noted) life-changing benefits.
For example, internet stuttering chat groups tend to become dominated by severe stutterers for whom therapy has not been much of a success. When providing supportive suggestions to each other, many members of these groups recommend everything BUT speech therapy -- from DAF and masking devices to drugs to attendance at support group conventions. A few others totally refuse to believe that modern stuttering therapy is even possible without a battery of high-priced specialists tweaking and poking every aspect of a stutterer's behavior and psyche.
I think that this situation can be improved by the development of a theory of stuttering behavior that answers some of the mysteries that undermine the trust of many stutterers in therapy and in the possibility of improvement. For this reason, I'm dismayed by the common and persistent failure to explain or even consider the role of conditioning in stuttering behavior, despite overwhelming clinical evidence that conditioning is the predominant mechanism in its development and perseverence.
In your paper, you jump from Kandel's seminal work with long term potentiation to a conclusion that stuttering is indirectly related to but somehow triggered by anticipatory anxiety, without referring to intervening and interpretive research by LeDoux and others that clearly implicates circuits associated with BOTH the hippocampus and the amygdala in conditioning. Certainly, the explicit emotional memories associated with the hippocampal circuits should be suspected, given the strong situation nature of stuttering and the involvement of the cortical areas (strongly linked to the hippocampus, of course) in the expression of stuttering. But the clear involvement of sensory feedback in stuttering behavior and of emotional conditioning associated with this feedback also implicates the amygdaloid circuits, which not only have cortical connections, but also connect to the PAG, the brain stem, and other areas which mediate threat and survival responses that influence key speech mechanisms, including phonation. Acknowledgement of the role of the amygdaloid circuits is essential because of their association with implicit emotional memories involving sensory and motor conditioning. At the root of many arguments against the efficacy of stuttering therapy is the notion that recovery involves *thinking* one's way to fluency or *controlling* stuttering, which of course is the best way to describe how therapy does NOT work (beyond the intellectual ability required to remain optimistic and just let things happen, at least). Providing clients with a rationale for the mysteries of recovery -- the process that Andreas Starke elsewhere in this conference associates with Zen -- would be a real benefit to the efficacy of treatment.
As to the lack of neuroimaging evidence that the hippocampus and the amygdala are involved with stuttering, I can only ask why such evidence would be expected in the first place? Unlike the cortical areas, the hippocampus, amygdala, and associated circuits are merrily working away at a pretty constant rate on a variety of tasks no matter what we are doing and have apparently been shown to delegate their activities to other brain areas, perhaps to ensure that the conditioning is rapidly expressed. And, given their involvement in evaluating virtually every aspect of human sensory experience and behavior (and particularly conditioning), the notion that these circuits are not involved in stuttering is pretty tough to swallow.
Again, despite my quibble, I appreciated your contribution here.
- Darrell Dodge, M.A.