Friday, March 12, 2010

Talk at Antwerp 2010 on April 24th

I will talk at the Antwerp Conference on April 20th about natural recovery in a neurological demand and capacity model.
Parallel session number: 22
Title: Explaining natural recovery in a neurological demand and capacity model
Session Format: 60 minute session
Day: Saturday, April 24th
Time: 1.30-2.30pm
Room: 2.06
Location: Lessius U College, Campus SINT ANDRIES

Here is the abstract and summary of my talk proposal that was accepted:
Explaining natural recovery in a neurological demand and capacity model

Why do most children recover? How do the neurobiological, behavioural and cognitive aspects of adult stuttering fit together? We developed a framework with a neurobiological basis, which we model to a first order approximation as a neurological demand and capacity model, acting
within a biopsychosocial framework. We show its consistency with neuroimaging and genetics evidence, but also with behavioural, cognitive and social aspects of stuttering. Moreover the NDC2 framework allows us to derive a conceptual (and mathematical) model for a possible explanation of natural recovery in children. We discuss its usefulness as a framework for further debate and to clinical practice.

Brain imaging and genetics suggest a neurobiological basis for stuttering whose exact nature and causes are unknown and most likely different for different subsets of people who stutter. Moreover, the consequences of a neurobiological basis and resulting re-enforcements are multi-dimensional and highly individual. An overarching framework is needed to capture the essential multi-causal and multi-dimensional nature of the disorder while at the same time providing room for individual causes and symptoms.

We propose such a framework taking a system performance view described with modeling techniques used for economic, financial, and computer systems facing similar issues of comparable multi-causal and multi-dimensional complexity, and embedded in a biopsychosocial framework. First, we assume that the core dysfunction is the abnormally high occurrence of abnormally long delays of speech initiation caused by an inferior system performance of the brain regions responsible in translating thoughts into spoken language. People who stutter abnormally often face a system overload for high but still normal demands because of a low system capacity leading to a delay in speech initiation. A demand and capacity model on the neurological level masks the multi-causal nature, because different causes can lead to a low capacity system. We compare the issue with inferior transport systems resulting from different causes but all leading to a low capacity and more traffic jams. Second, we then look at the consequences of such abnormally frequent and long delays in speech initiation and derive the observable range of primary stuttering symptoms. Third, we work within a biopsychosocial framework that we have developed for a related book project. Human behavior is determined by four systems: the biological system, the two types of information stored within our brain (communicable and non-communicable via language), and the environment. We show how an inferior biological performance interacts with the three other systems in acquiring learned associations, motor codes, and episodes, but also unhelpful cognitive constructs. All are re-enforcing each other leading to full-blown adult stuttering. To summarize, the framework is based on a neurobiological basis, described by a neurological demands and capacity model, impacting a second level, the psychosocial: NDC2.

The NDC2 framework allows us to discuss any puzzling aspects of stuttering. We apply NDC2 to give a possible explanation to the natural recovery from early childhood stuttering. We assume that the schedule of development for the capacity of different areas is different in different children, driven by genetics and environmental forces. Sometimes a temporary relative mismatch between different areas exists. We show that this developmental difference can naturally explain why many children recover and some do not. We also discuss whether the model can capture the gender specificity of recovery, and how the model can inform clinical practice.

We discuss the range of applicability of the framework. The emphasis is not to explain every single detail of every person who ever stutters, a practical impossibility forever, but rather capture the essentials of the disorder. Most importantly, we argue that NDC2 provides a clear conceptual and mathematically describable framework within which a constructive debate can happen.


Ora said...

Tom - You pose the question as "why do most children recover?"

I would approach it from a different angle: "Why do some children pass through a period of stuttering?"

Your formulation takes stuttering as a baseline, and wonders why there's a change from the baseline. My formulation takes normal speech as a baseline, and wonders why some children temporarily diverge from the baseline.

Tom Weidig said...

It is the same question really.

My answer would be that the neuro capacity to cope with neuro demand is temporarily lower due to developmental asynchrony. For those who keep on stuttering it is staying permanently lower.

Both groups develop behavioural and cognitive reactions to jams in the brain, but the group that recovers only has jams for a brief period.

Gustaf said...

My question is more practical: how do you prepare for a speech like this? Is there any form of practice that goes into your routine, apart from reading the material?

Tom Weidig said...

To Gustaf,

I had been written the speech for 1-2 years now in my mind!

So I pretty much know what I want to say, and when I actually write it down I fill in the details.

Best wishes,

Ora said...

Tom - I don't want to speak for Gustaf, but I suspect what he was wondering was how you prepare to manage your stuttering while you present a speech. Do you do anything to prepare? Do you practice the speech perhaps by reading out loud or working with someone? Do you have any specific techniques which you find helpful during the delivery of a speech before an audience?

Anonymous said...

Jones, M., Onslow, M., Packman, A., & Gebski, V. (2006). Guidelines for statistical analysis of percentage of syllables stuttered data. Journal of Speech, Language and Hearing Research, 49: 867-878.

Is this good research, good science article in your opinion?

Anonymous said...

This workshop sounds riveting....

Tom Weidig said...

Well, Having seen how Jones has messed up the random control trial statistics, I have no great faith in this article a priori...