Frank's gene mutation

Frank was so kind to write up his experience of having been diagnosed with a gene mutation that correlates to stuttering. I am not exactly sure whether it is the 3-gene system that everyone talks about. What is also interesting is that people with Ashkenzi ("Central/Eastern European") Jewish ancestry seems to be more likely to have this gene mutation. It is very likely that as genetic subtypes seems to exist, they are more prevalent in some ethnic groups.

Frank reports...

I became involved in the study via my participation in the NSA convention that took place in New Jersey (where I live) in 2008. I attended Dr. Drayna's workshop on the genetics of stuttering and during the course of the workshop he asked participants in the workshop who stutter and have family members who stutter to donate a blood sample for inclusion in his study. My father stutters so I volunteered to provide the blood sample. 

Several months later he called me to say that I had the genetic mutation they where studying; that this genetic mutation on chromosome 12 was related to the rare genetic disease of mucolipidosis. He said there was some indication of stuttering in some patients with mucolipidosis. He invited me to come to the NIH in Bethesda, Md. for several days for a complete study of my physical and sensory systems to determine if I had any other physiological changes associated with this disease.I was very interested in this study, after doing a little research about this disease on the web, as some forms of it are more common in members of the Ashkenazi Jewish community of which I am a member. 

I spent three days at NIH. Dr. Drayna mentioned that I had a double copy of the mutation but didn't get the disease as I lack a likely "starter gene" required to get the full blown disease. I received a complete physical while at NIH; they seemed to be especially interested in the skeletal system and took numerous x-rays. I recall receiving EKG and EEG testing and very likely other tests I don't recall. I should mention the staff was very pleasant and accommodating and both my wife and I stayed at the Safra Lodge at NIH that was very pleasant. 

At the conclusion of my stay at NIH I was I was told they didn't find physical abnormalities other than some spinal arthritis common in people my age (I'm 62); they also didn't correlation with severity of stuttering and the presence of this mutation. They were kind enough also to send a copy of the study results as they appeared in the New England Journal of Medicine in 2010. 

This study has had a significant effect on my attitude toward my own stuttering as I now believe my stuttering has a strong genetic component and I'm much more accepting of my disfluencies. 

Genetics Update or Why our community is at least 14'000 years old

Yes, even the Flint Stones might have had to listen to stutterers...

Check out StutterTalk's Peter's as-always excellent interview with Denis Drayna on the "latest Drayna wants to tell us about genetics as of December 2012". Some exciting news: biochemical experiments show that the gene mutation reduces activity of an enzyme by half, the earliest known mutation happened 14'000 years ago, roughly 10% are of the 3-gene subtype, and many more gene signals found.

All-in-all, congratulations to Dennis Drayna's team for their hard and constructive scientific work.

Here are the key nuggets of knowledge and insight that I picked up and commented:

1) They studied the effect of the mutation of the 3 genes of the identified cycle and they see a reduction of the activity of the corresponding enzymes ( a form of protein that accelerates chemical reactions to help the body to produce the stuff it needs to live) by 50%. This fits neatly to a reduced (but not zero) capacity of the brain to function normally in speech. Think of my motorway analogy: we have 2 lanes instead of 4.

2) As we know, more than one gene mutation in the three-gene cycle causes a severe disorder, but only one mutation correlates to stuttering. They also did the biochemical experiment for 2 or 3 mutated genes out of 3, and got a dramatic reduction of 90 respectively 100% of enzyme activity. This neatly explains why 2 and 3 mutation lead to a severe disorder and a single one does not as the body is just about able to handle it biologically.

May Conference at Hotel Croatia

Check out the website of the upcoming May conference in Cavtat at Hotel Croatia: see here.

All the speakers are relatively well-known and some of the most dynamic researchers in the field. I just find it a bit strange that Katrin Neumann talks about the state of genetics, and not about brain imaging, because she is not a geneticist or worked in the area. And as always I am concerned when experienced therapists think they can do proper outcome research. Please share your experience with us not your faulty scientific expertise.

Yet more evidence for strong heritability from twin studies

Fagnani, Fibiger, and al. have just published a twin study using a database of over thirty thousand twins. Their findings are consistent with past twin study results (see on old post of mine on the Dworzynski study). They find a high heritability of 80%, and only moderate unique environmental effects. Note that they do not mention shared environmental effects.

This finding fits my view on stuttering. Genetics drives the onset of stuttering in many people. The other factors (alone or in combination with genetics) are internal developmental issues caused by unique environmental events like neurological incident, virus and head trauma. Only some of these events were reported in the twin study, so the effort is measured as moderate. Needless to say that, as in many other conditions, the social environment plays a negligible role in the actual onset.

Here is the abstract:

Heritability and environmental effects for self-reported periods with stuttering: A twin study from Denmark.

Fagnani C, Fibiger S, Skytthe A, Hjelmborg JV.

National Centre for Epidemiology, Surveillance and Health Promotion, National Institute of Health, Rome, Italy.

Abstract

Abstract Genetic influence for stuttering was studied based on adult self-reporting. Using nation-wide questionnaire answers from 33,317 Danish twins, a univariate biometric analysis based on the liability threshold model was performed in order to estimate the heritability of stuttering. The self-reported incidences for stuttering were from less than 4% for females to near 9% for males. Both probandwise concordance rate and tetrachoric correlation were substantially higher for monozygotic compared to dizygotic pairs, indicating substantial genetic influence on individual liability. Univariate biometric analyses showed that additive genetic and unique environmental factors best explained the observed concordance patterns. Heritability estimates for males/females were 0.84/0.81. Moderate unique environmental effects were also found.

Disastrous NSA key note speaker?

The choice and message of the key speaker, Sander Flaum, at the NSA conference seems extremely popular with informed people who stutter. He is the typical key note speaker, the type that the informed person who stutters hates. They never studied stuttering in depth nor do they have the intellectual and scientific ability to realize their limitations in understanding, they never worked with many different people who stutter or followed them over several years, they never attended other conferences but are parachuted in (mostly because the organizers hope to get them to give them money!), they all stutter relatively mildly or not at all, and finally talk about their glorious interpretation on stuttering even though they have no clue whatsoever.

Why don't they let people talk who know what they are talking? Or if you really want to roll in those "successful" people, tell them to talk about their experience and not their glorious interpretation!

Why don't we start a campaign that allows NSA members to VOTE WHO THEY WANT TO HAVE AS A KEY NOTE SPEAKER!

Check out StutterTalk's conference chat, and this reader's comment:

The Keynote Speaker for the NSA Convention basically said that every person who stutters can become completely ---100%--- fluent if they will commit to all the practice that is required. It is the fault of the PWS that they "FAIL" in therapy. Fluency Training is the CURE...JUST PRACTICE. EVERYONE WHO STUTTERS CAN BE FLUENT; YOU MUST PRACTICE THE TECHNIQUES.

FANTASTIC message for all the speech pathologists out there and the parents of CWS demanding that their CWS practice more in order to stop stuttering!!!

CRUSHING message for all of us who stutter who know that this is not true...

ABSOLTELY EVIL message for 1st time parents to hear...For kids who stutter to hear. Totally F***** UP!

What is the NSA Organization thinking as they choose Keynote Speakers???

I feel like making like Lebron and leaving this thing...

How safe are the lysosomal stuttering genes?

I have written about the claimed discovery of mutations in three genes affecting a lysosomal pathway: search for Drayna. I also spoke of the most important scientific discovery in stuttering so far, assuming the research is correct. Over the last weeks I have received emails who are skeptical about some aspects of the article. I also know that someone is preparing an article questioning the validity of the findings.

Here is a taste of the skepticism:

I have shared the paper with a couple of top notch human geneticists - who, in turn, thought that the paper was a bit of a joke. As one pointed out, if this was the profoundly important finding that NEJM's editorial claimed it to be, then publishing it in NEJM would be akin to Watson and Crick publishing their 1953 paper in Popular Mechanics rather than Nature!

I believe at least one of these individuals is preparing a formal critique for publication. However, he has already flagged a number of problematic issues, including the Figure 1 data, the large number of unattached technical labels, and the failure to report whether those with the mutation suffered from other far more serious conditions (a likely result of lysosomal enzyme disease is developmental regression). As we know, Down's Syndrome patients have been reported to have an abnormally high incidence of stuttering, but their speech disorder is a relatively minor part of their condition. And, of course, not all persons who stutter have Down's Syndrome. You suggest that what Kang et al. might have found is a sub-type of the stuttering population (maybe,

Bigger disconnect will not correlate strongly to severity

ig88sir asks:

Does anyone think that a bigger disconnect (i.e.,weaker myelin sheath) has a correlation for stuttering severity? It is a naive simplification but seems to make sense to me. They should do imaging with mild and severe PWS to find out.

 I hold the opposite opinion:

1. Two different dynamics are affecting severity of stuttering. 
1. The frequency and length of delays in speech initiation due to neurobiological deficits.
2. The instinctive reactions to speech delays, and acquisition of learned behaviours and cognitive schemes, which can also impact neurobiology.
3. Factor one might well be directly affected by the disconnect, but a disconnect is only one and probably not even the most important factor in shaping the reaction and re-enforcements.
2. A slight disconnect might actually make the delays worse, because the brain either
1. does not compensate neurobiologically speaking, or
2. compensates but the weak route is still active, so there is interference between two routes.
3. A severe or full disconnect might force the brain to compensate leading to temporary developmental issues but in the long term that compensatory route is working fine, and there is no interference from the bad fiber connections.
4. The brain imaging studies show a significant overlap between the pws group and controls. Some controls have a lower fiber coherence than some stuttering people. The difference is also apparent in the population, i.e. the average coherence between the two groups.
5. The NIH study in recovered stutterers found that the recovered ones had more structural abnormality.
6. The genetic studies (including the twin studies, I think) have not found a strong correlation between the severity of twins who stutter.

So I would not be surprised that there is no strong correlation between disconnect and severity.

No pill makes you a good public speaker

A reader asks me about medication, because he needs to give an important speech. Here is what I replied:

You do not need medication. You need to challenge yourself. You need  to start working on yourself and not try to find quick-fix solutions that don't exist! You cannot become a good sportsman by taking pills, you need to train.

You need to get at ease when speaking in front of groups so that it feels like talking normally. That's a conditioning and learning process that everyone can do, but it takes time and you have to face
your fears.

There is only one way to do this: to continuously speak in front of people.

I recommend you join a Toastmaster club. Many stutterers have found this useful. Spend the money on the membership fee!

Here is what I did: http://www.youtube.com/watch?v=YrQCIEKYxMY

You can do that, too!

The more speeches you give the more relaxed you feel and the less likely stuttering will be triggered.

 

NSA conference 2009: Genetics

There was a research symposium at the NSA conference 2009. A Stuttering Brain reader sent me his notes and comments. If you have more, please send them to me. You can also order a DVD, but I wonder why they don't just put them on Youtube for everyone to see. Behnaz also blogs about the symposium here but I am absolutely not impressed by her summary which seems more like parroting the announcement and meaningless hyping and repetition "...invited five top researchers who represent the “who’s who in the world of stuttering." I hope her promised in-depth summary will be real journalistic work.

The most interesting and scientifically most rigorous talk was surely from Dennis Drayna, the leader of an NIH genetics team entirely dedicated to revealing the genetics of stuttering. Jerry Maguire, the chief investigator for the Pagoclone, was also there, but the trials are still running and an article for Phase IIa is still nowhere to be seen in a journal and other reports are fuzzy at best. Larry Molt had the audacity to talk about auditory devices (so I heard), but at the same time he has ignored emails from several different people asking him about the results of his studies but has time to attend conferences, obviously not having published the research study anywhere in a journal for the wider public after more than 5 years and providing actively or passively a cover to Speech Easy to hide the lack of evidence on Speech Easy; unacceptable and unprofessional behaviour in my mind and in the minds of others who as usual dare not to speak out for political reasons. I would like to know what he said in his talk.

I will just focus on genetics based on previous talks I saw and on a reader's notes:

• 50% have a family history i.e. genetics component.
• other half unknown but could probably neurological incident like perinatal hypoxia
• severity varies significantly within and across people though genetics component is stable.
• stuttering therapy can eliminate but genes stay. [Tom: only temporarily in most cases]
• stuttering families most interesting: focus on Pakistani families. [Tom: there is also a Cameroon families but the studies are less reliable also because the family trees are less "stable" i.e. too many affairs... ;-)]
  
• on 44 families: identified region on Chromosome 12 which contains about 90 genes.
• major article in science journal under review and news embargo. [Tom: could be the identification of the one of the 90 genes. As always, I completely disagree with the big journals policy, they are destroying real debate and make scientists look like schizophrenics]
• mutation in that gene is related to stuttering in that family, in other families, and unrelated Pakistani individuals.
• gene codes for protein that is part of a metabolic pathway. [Tom: If I had to bet, I would say it's dopamine pathway. Would fit with the Chinese article and suspicions from various sources that the basal ganglia is dysfunctional in at least some stutterers.]
• two other genes were localized, where the mutations are related to stuttering.
• the three genes account for less than ten percent of all familial stuttering.
• work is in progress on another Pakistani family on Chromosome 15 but is more difficult to do. [Tom: maybe it is more than one gene, but not sure.]
  

Here is my take. No surprises here but would be nice to finally hear the name of the first identified gene of stuttering! Genetics of stuttering is not about one gene, but about many different genes that are related to stuttering, like in other disorders. For example, deafness has 10s of such genes. The work is not easy and not many teams are working on this. We should not pin our hopes on a genetic cure, but rather on finding more and more mutations in genes, and hope that those genes' function is already understood from other experiments and disorders. Such insight can give us better clues on what can cause stuttering in this specific case of a genetic mutation and in the cases where a neurological incident has affected the same functions that the gene's proteins provide. Again, genetics seem to suggest that there are many different ways on how the speech system can break down and induce dysfluency. This has an impact on how stutterers are treated, and might explain why some can recover better than others. But such an approach requires very sophisticated expertise. And again, genetics provides the seed for stuttering but does not seem to condemn us to a life of stuttering but rather forces us to live with a sensitive speech system and to struggle with controlling our learning bad habits, associations to stuttering, psychological reactions, and social handicap.

More on genes from China

I reported on this genetics article from China, now published in a Western journal: J Hum Genet. 2009 Jul 10 which should increase our confidence in its quality. The research suggests a link between genes active in the dopamine (a brain chemical) system and stuttering. Dopamine acts on the connections between neurons in two ways via the level of dopamine and via the level of dopamine receptors that modulate the dopamine level. Jerry Maguire suggests to me that the result

helps to support their dopamine hypothesis of stuttering that an over activity at D2 receptors contributes to stuttering. Many of our successful medications specifically target the D2 receptor i.e. risperidone, olanzapine, aripiprazole and others.

I also emailed Dennis Drayna but he didn't reply.

Here is the abstract:

Association between dopaminergic genes (SLC6A3 and DRD2) and stuttering among Han Chinese.

Lan J, Song M, Pan C, Zhuang G, Wang Y, Ma W, Chu Q, Lai Q, Xu F, Li Y, Liu L, Wang W.

Department of Genetics, College of Life Sciences, Graduate University of Chinese Academy of Sciences, Beijing, PR China.

Normal function of the dopaminergic system is necessary for speech fluency. There was evidence that the activities of dopamine transporter (DAT) and dopamine D2 receptor (DRD2) could be altered in people with speech disfluency. This study aims to ascertain the possible correlation between two dopaminergic genes (SLC6A3 and DRD2) and disorder of speech fluency, and to determine the allelic frequencies of the five single-nucleotide polymorphisms (SNPs) (rs2617604, rs28364997, rs28364998 in SLC6A3 and rs6275, rs6277 in DRD2) among Han Chinese patients with this disorder. A sample of 112 patients with speech disfluency and 112 gender-matched controls were included in this case-control study. The results show that the presence of C allele at rs6277 in DRD2 gene is associated with increased susceptibility to the disorder, whereas T allele is protective. Haplotype 939T/957T is also a protective factor. Journal of Human Genetics advance online publication, 10 July 2009; doi:10.1038/jhg.2009.60.

From an evolutionary perspective

Stuttering has a genetic component. First, homozygotic twins are more likely to stutter both than heterozygotic twins. Second, several locations on chromosomes are correlated to stuttering. These two sources of evidence in combination with research from other disorders allow two conclusions. First, there is not a single gene for stuttering, but many different ones or combinations of. (For example, deafness is associated to tens of different genes.) Second, genes are not a sufficient condition to develop stuttering in all people: if you have the genes, you could be fluent. And if you dont have the genes, you could develop stuttering. However, the likelihood of being in the stuttering group is influenced by the genes. For the non-genetics group, it is likely that a neurological incident (possibly enhanced by environmental stress) kickstarts stuttering. Examples would be an infection or a brain trauma, whose likelihood could also be related to non-speech related genes. Such genes would probably not show up in correlation studies as their signals are too weak and multi-factorial.

Due to its genetic component, stuttering is a candidate for evolutionary adaptation. About 1% of the population stutters, and did not recover naturally from the sample of 3-5% of children who temporarily stutter. It is interesting to look at the past history of stuttering, and ask whether this ratio was stable throughout the evolution of speech in humans, or whether in fact the proportion of the stuttering population was greater in early humans. If the proportion was indeed greater, there must have been evolutionary pressure that reduced the proportion to the 1% of today. (A gender perspective would be even more interesting, as women are 4 times less likely to develop stuttering. This could suggest that they were under greater evolutionary pressure, however this might not be directly linked to speech but more general pressure that favours stable and fast maturity of females for the survival of tribes.) The question is whether this scenario makes sense theoretically and fits all known data, and if it makes sense, whether nature took this course, and whether experiments can be devised to check predictions.

The mechanism of exactly how and why evolutionary pressures made humans evolve speech unlike in their closest relatives the apes is not clear. It is reasonable to assume that humans started out like the apes of today in that they used different sounds with different intonation to communicate mental states. The crucial aspect that gave advantages to early humans is probably the emergence of rudimentary grammar that allowed early humans to combine those tens of sounds representing general concepts into thousands of different sentence combinations. However, grammar requires extra brain resources/modules. So instead of a mental concept being associated to one sound and going to the motor cortex, it now took a detour to a new region that combines words into sentences to better represent and communicate a mental concept. This ability to create sentences imposed great pressure on the brain and at the same time more greater fine motor control of the muscles is needed. A reasonble guess is that the brain divided up the pathway of making sounds into two: one old for sounds (how we speak), and one more recent for automatic speech where the early human could focus on what to say (and also on how to combine words) as opposed to how (intonation) he would say it. The social and natural smile might be an analogy.

It is reasonable to assume that nature favours fluent speakers. This is especially true as early humans became more and more organised in tribes, and social skills and communication skills became important, and a lack thereof a distinguishing feature from others. The evolutionary pressure only started when fkuency became important. So it might well correlate with emergence of culture. (Another example would be genes for dyslexia, that could only have been exposed to evolutionary pressure when writing became important, unless dyslexic have other defficiencies.)

It is possible to at least in principle falsify the theory. My theory is that early humans had more genes creating unstable speech, stuttering,and these are being selected out by evolutionary pressures. So the theory predicts that a higher proportion of early humans carry stuttering genes. So a comparison between a sample of modern humans and early humans would reveal sample differences. In practise, such a test is not possible yet as old DNA degrades relatively fast, unless preserved under special conditions. The promising news is that new techniques are being developed to extract ancient DNA. For example, such techniques have been used in Neanderthals with an age of tens of thousands of years. So there will probably be a DNA bank at some point in the future on ancient DNA which could be used.

Genes located?

Look at this intriguing article from China. They seem to have found a genetic relationship between dopamine and stuttering. However, I am not geneticist, so I do not know exactly what the result means and whether the results are reliable or not. Maybe a reader can help us out?

Nan Fang Yi Ke Da Xue Xue Bao. 2009 Mar;29(3):375-80.

[Single nucleotide polymorphisms of DAT and DRD2 genes in Han Chinese population and their association with stuttering.]

Pan CH, Song LP, DU J, Lan J, Wu CM, Wu LJ, Lin L, Wang W.

Graduate School of Chinese Academy of Sciences, Beijing 100049, China.

OBJECTIVE:

To explore the correlations of dopamine transporter gene (DAT) and dopamine D(2) receptor gene (DRD2) to stuttering. METHODS: To examine the correlations of the 5 single nucleotide polymorphisms (SNPs) in dopaminergic gene (C252T, C1804T, and C1820T in DAT gene, and T1054C and C1072T in DRD(2) gene) to stuttering in Han Chinese individuals, a case-control study involving 112 patients with stuttering and 112 gender-matched controls was carried out. Genotyping was performed by a combined approach using polymerase chain reaction (PCR) and pyrosequencing.

RESULTS:

C1804T showed no polymorphism in either the patients or the control subjects and was therefore excluded from the following analysis. The C allele frequency at C1072T site was significantly higher, but T allele frequency significantly lower in the stuttering group than in the control group. The patients had significantly higher CC and lower CT genotype frequencies than the control group. There were no significant differences in the allelic frequencies of C252T, C1820T and T1054C between the patients and the controls, suggesting a Hardy-Weinberg equilibrium at these 3 loci. CONCLUSION: The presence of the C allele at C1072T in DRD(2) gene is associated with increased susceptibility to stuttering in Han Chinese, whereas the T allele provides protection against the onset of stuttering.

Solutions to Logical Fallacy IV-VI

Here are the last three fallacies.

IV: Statistical Fallacy

A researcher says: "We have tested 100 kids who stutter on 20 variables and found 2 that were significant (p<5%). Therefore, I conclude that onset of stuttering is correlated to these two variables."

Explanation:
The researcher has committed the mistake of over-fitting the statistical model, because the more variables you look at the more likely one correlates by chance! And if he uses p<5% as a threshold, one in 20 variables will [Correction: is likely to] show a correlation by chance. Moreover, he has only looked at p-value, but effect size is absolutely crucial. The p-value only says whether two distributions are from the same underlying distribution, and any outlier or systematic error can easily lead to low p-values. Therefore, he needs to look at the size of the difference as well.

V: Treatment-Sucess-Factor-is-Cause Fallacy

A person who stutter says: "After I have come to terms with my childhood trauma and undertook psychological treatment, my stuttering vastly reduced. Therefore, stuttering must be caused by a traumatic experience in childhood."

It is true that his psychological treatment has helped him greatly. However, the cause might still be of non-psychological nature that triggered psychological issues that affected his stuttering severity. If you have a car accident and are in shock, psychological therapy might help you to overcome it, but that does not mean it has causes the accident.

VI: Timing fallacy

A researcher says: "We have recently launched a large-scale study to study kids around the onset of stuttering, because we want to find out what causes stuttering."

The researcher assumes that the causes of stuttering lies close to the onset of stuttering, but that could well not be the case. For example, genetics clearly played a role in many cases of stuttering, and the genes were there from the beginning onwards. Or a neurological incident in the womb or later like a virus infection or a head injury could be the cause, but is not close to the onset of stuttering.

Stuttering: a developmental disorder?

Sorry for the few posts over the last weeks. I am currently on a France round trip, and I will be at the Antwerp stuttering conference on Friday and Saturday. I will report on the conference.
Today, I want to talk about stuttering as a developmental disorder. The term is misleading. Let's assume stuttering is caused by genes (as it is in some families), how can you possibly label stuttering a developmental disorder??? After all, the body has developed smoothly according to what the genes instructed! The final results might well show deviations from the normal population that became apparent during the development of the child, but that is hardly a developmental disorder per se? On the other hand, if stuttering is caused by a neurological incident like a virus infection or head injury, the smooth development of the brain according to what the genes instructed has definitely been disrupted, and we can call it a developmental disorder.
People seem to define a developmental disorder, a disorder that becomes apparent when the child is in development. So it is based on symptoms. This way of thinking is highly misleading and confusing.

Primary and corrective-feedback phase of stuttering

From time to time, I have these flashes of enlightenments which either quickly vaporise or stay and I see clearer. Actually, it becomes so clear that I am wondering whether not everyone knows that anyway because it is so simple, and that I was just too stupid to have realised.

Stuttering goes through two completely different phases, the moment of onset being the phase transition. In the first phase (the primary phase), the subconscious brain, the person that lives with the brain, and its environment knows nothing about the abnormal nature of the brain. It is functioning happily. Still, the abnormality is there and detectable, and caused by either genes or a neurological incident. The phase transition happens at onset of stuttering. The moment of onset per se is nothing special at all, as its causes go back years, back to the genes or the neurological incident. It is like the emergence of a rock when the tide goes out again. The moment of the rock emerging looks special but it is not the rock that is not emerging, but the water that is receding and for the water it is nothing special at all! Still, something dramatically has changed that triggers a feedback loop leading to the corrective-feedback phase. Suddenly, the subconscious brain, the person of the brain, and the environment realise the abnormality, because it leads to atypical and functionally disruptive behaviour: dysfluent speech plus secondary effects. Immediately, corrective behaviour sets in by the brain, by the person who stutters, and by its environment. The future development of the disorder now depends on two things: the severity of the underlying abnormality, and the correcting ability of the brain (brain plasticity), the person who stutters, and its environment. And, the goal is clear, too: to change the atypical behaviour to within normal and functional behaviour. Note that the emphasis is on correcting behaviour, whether the brain is still abnormal is irrelevant as long as it produces normal behaviour. Of all the children who start stuttering, a majority of eighty percent manages this task well, the others like myself go on to become adult stutterers.

How to tackle complexity

Stuttering is a very complex disorder, and I want to talk about strategies to control this complexity in order to understand the underlying dynamics. They are mostly inspired from methods or tricks that I learned from fellow physicists.

- Always remember that every phenomenon no matter how complex is ultimately an interaction of atoms! There are no ghosts or paranormal forces or magic at work. There are better explanations for why something happens, but sometimes it is damn difficult to achieve understanding. In some cases, it might be (nearly) impossible, like in fluid dynamics, climate models, social interactions, but nowadays computer simulations are very helpful in reproducing complex phenomena whose internal dynamics we do not understand theoretically.

- Do not talk to people who advocate a "holistic approach" or "to view every person as an individual" consciously or unconsciously acknowledging defeat to complexity. They are like the ancient tribes assigning a God for every phenomena they do not understand, or the 18/19th century scientists inventing concepts like elan vital as the fluid that makes matter come to life, like the calorific fluid that transfers heat, or the ether to give classical physics alive. They are only stating the obvious that we already know, namely that stuttering is a very complex disorder. Very rarely, do they have to say anything deep. We must strive for better explanations and not give up.

- Construct theories up to a first order approximation first. For example, we conveniently talk about males and females, but there are some people who are different physically or genetically. Or, let's take planetary orbits. At a first order approximation, they are circles, at second order they are ellipses, at third order they are ellipses with some correction due to the other planets, and at fourth order, these corrected ellipses have corrections from general relativistic effects.

- Cut out sources of complexity that are not fundamental to the disorder. Here, I would put psychological and social consequences of stuttering in this group. I am purposefully ignoring them, not because I think that they are not important in other areas like therapy but because they add considerable complexity without adding much insight into the underlying causes. A clearer example is hair loss. There is a wide range of complex reactions in males and females and their environment, but they tell us nothing about hair loss itself.

- Throw out any atypical cases. In stuttering, we need to "get rid" off people who started stuttering after age 7, who have undetectable dysfluencies, who have other disorders, and even who are females in the case of brain scans. This relates to the first order approximation in that we need to first try to understand the typical cases. Clearly, this atypical group might well be a source of inspiration and explain the typical behaviour better.

- Look at every possible dimension you can think of independently. Here are a few: brain imaging, self-reports, genetics, therapy, phenomenology, linguistics, child development, and so on. But, it is clear that a full picture only arises once you look at all dimensions at the same time and look for the interactions between the dimensions. Nevertheless, you should first understand each dimension independently.

- Concentrate on more quantitative dimensions where you can get clearer and more OBJECTIVE results. Genetics is the king here, because the DNA is well-defined. For example, we know due to twin studies that genes have a big influence, but how it happens we have no clue. Still, we can identify genes and bypass the enormous complexity.

Crackpot award for Jerry Halvorson

I received emails from Jerry from http://jerryhalvorson.com/, and as you can see below he is propagating statements about stuttering that is not supported by hard evidence and has no intention to change his mind. As I have done in the past, I am rigorously exposing such people. (I am not saying he is a bad person intentionally, but he clearly has a responsibility of checking facts before "educating" people who stutter.) I give him my crackpot award: see here.

Hi Tom,
Noticed your blog…thought you might benefit from reading my new book on stuttering, Regression Therapy For Stuttering. Check out my website for details jerryhalvorson.com
Jerry

Hi Jerry,
>>> The wrong word, spoken at the right time to a vulnerable child can be devastating. People who develop speech avoidance are victims of accumulated traumas that are shuttled into hiding.
1) How do you explain that genetics research has shown that genes contribute about 70% to the occurence of stuttering. For example, twins which share the same genes (monozygotic twins) are 3-4 times more likely to stutter both than dizygotic twins?
2) How do you explain that the vast majority of kids who experience trauma do not become stutterers?
Tom

Hi Tom,
Great questions…ones asked often…Short answer=all depends upon STUTTERING DEFINITION
Jerry Halvorson

Hi Jerry,
sorry but that answer is not good enough for me. So what is your definition of stuttering?
You also claim that the Monster Study has caused children to stutter. This is factually not correct as the claimants of the compensation trial were rewarded damages not for existing stuttering but for psychological trauma and others.
Best wishes,
Tom

Hi Tom,
My book, Regression Therapy For Stuttering, will answer your questions.
Jerry

Hi Jerry,
With all respect, but that is a very cheap answer and you are avoiding the answer which of course you cannot have because what you say is not supported by evidence. You should be more careful what you write, because there are many real people out there who suffer from their stuttering and it is my duty to present them with hard evidence. Stuttering is not caused by traumatic events in childhood. That is the opinion of all leading therapists and scientists.
Tom

-no more emails-

Stuttering produces no genuises

This Telegraph article describes that Prof of Psychiatry Fitzgerald believes:

"Psychiatric disorders can also have positive dimensions. I'm arguing the genes for autism/Asperger's, and creativity are essentially the same.

I only agree to some degree. A mild form of autism might push people to do extraordinary work, but in the vast majority of cases they just suffer from their disorder without doing any high standard work. Some researchers even view autism as an extreme version of a male brain with more of its strengths and weaknesses!

A reader has sent me the article and asked whether this is also true for stuttering. First, stuttering is not a psychiatric disorder but a motor-control and integration problem that leads to psychological and social issues. We have an average brain with average capabilities. Second, I would argue that any disorder that doesn't kill you and that can be overcome to some degree may be a source of motivation. The saying goes: What doesn't kill you makes you tough. I have seen many people who stutter who were successful because instead of giving up because of stuttering draw an enormous amount of drive and motivation from it. And, it is an open secret that over-protected kids from caring and wealthy families rarely make it big; they just don't have the need to do so. With exception of Paris Hilton, maybe. Of course, we need to contrast this with the many (in fact the majority of people) who live a life below their potential due to their stuttering.

Finally, let me assure you that even if stuttering does not lead to geniuses, stuttering does not prevent you from being a genius either! So there is hope for us all. ;-)

Twins: Little shared environmental effect

I have just re-read the 13000-twin study by Katherina Dworzynski et al and she clearly empirically confirms what I have been saying in my last posts:

Stuttering appears to be a disorder that has high heritability and little shared environment effect in early childhood and for recovered and persistent group of children by age 7.

And further,

With respect to the genetic effects throughout, it also needs to be emphasized that, even though substantial estimates of heritability were obtained, many monozygotic twin pairs were discordant for stuttering. This is further evidence for the importance of the child's unique environmental influences, in that specific stressors have unique effects when a genetic liability is present.

Again, the nature vs nurture fallacy is revealed. It is simply wrong to divide the world into nature and nurture. There are three categories: the genes (nature), unique environmental stressors (more or less random events), and shared environment effects (nurture). Think about being the CEO of a small start-up company. Unique events like you having a car accident or a virus infection, sheer bad luck, pregnancy of your most important employee, and so on can completely change the outcome of your company's success because you only have a few months of financing to hit a certain target before your bank or venture capitalist cuts financing (window of development for child). I have seen this many times. Of course, you are especially vulnerable to such events if you have a bad or weak business plan (think of this as the genes - the instructions on what to do). General market conditions are also important but not that crucial, and can increase or decrease vulnerability. I never thought that venture capital, the topic of a book I have written (see here), is relevant to stuttering! :-)

The Genain quadruplets

The Genain quadruplets are a "beautiful" experiment of nature that can teach us a lot about genetic and environmental factors. All four girls share exactly the same genes, and lived in the same family environment. Unfortunately for them but fortunately for science, they share exactly the same genetic predisposition to schizophrenia. In exchange for free treatment, the quadruplets were and still are monitored; they are now about 50 years old. Interestingly, the expression of schizophrenia was very different between the quadruplets: Myra after an initial episode was never hospitalized and is married, Nora was hospitalized repeatedly but had marginal adjustment while outside the hospital, Iris experienced more-chronic hospitalization and her symptoms range from severe catatonic withdrawal to times of marginal adjustment when she was able to leave hospital, and Hester further deteriorated and remains hospitalized! Check out this review: here.

The case study shows that the same genes for schizophrenia (and many other brain disorders like stuttering) can lead to very diverse outcomes, though all quadruplets did develop schizophrenia. The family environment including parenting skills (nurture) were the same for all four, though parents might have treated them differently. However, a difference in treatment is mostly due to the kids being different. So the parents react to the difference of the child.

So why do the Genain quadruplets develop so differently? The answer lies most likely in environmental stressors unique to a child. I would split it in pre-natal and post-natal factors. Pre-natal factors include the position of the child in the womb in relationship to the others, differences in weight due to differences in nutritional supplies, injury, and so on. And post-natal factors include illness, injury, unique random events like a traumatic experience, reactions of parents to behavior proper to one child and so on.