Friday, July 1, 2011

Per Alm's Comments on Blog

Per Alm sent this stimulating commentary regarding this blog:

Thanks for a very good and well written blog. It seems like you are doing a thorough work, and that your are an independent thinker -- the anonymous format may make it easier to be strait about what you think. A blog like this can play an important role in the striving for a better understanding of stuttering.

Regarding this posting I just have a comment about a detail: "Parkinson’s disease victims, like stutterers suffer from deficiencies with their dopaminergic systems. But their problem is too little dopaminergic activity rather than too much as in the case of stutterers."

I think it is not likely that stuttering persons in general have too high dopaminergic activity. My guess, based on available data, is that anomalies in the dopamine system may be an important factor in some cases of stuttering, but that it is not a core factor in the majority of cases. (For one thing, dopaminergic hyperactivity could be expected to have more widespread effects on personality and other functions. The majority of persons who stutter do not differ from the general population when it comes to personality/temperament, though a subgroup seems to show mild traits of ADHD/ADD.) Further, it is also possible that some cases of stuttering rather is linked to hypo- than hyperactivity of the dopamine system. For example, there are some reports of improved stuttering from dopaminergic stimulants (see summary in Alm 2004, review on basal ganglia, Journal of Communication Disorders).

Another important point is that a partial improvement of stuttering symptoms when using D2 blockers does not necessarily imply that the dopamine system in this person is deviant. D2 blockers reduce the general activity in some brain circuits, which in some cases may improve the overt symptoms of stuttering even if the basic cause is not related to dopamine.

The reason I write this is not that I'm negative towards this type of ideas or towards pharmaceutical trials on stuttering (I'm not), but because there is a risk that a single possible factor gets too much focus and that the great heterogeneity in the stuttering population may be overlooked.

Another thing I would like to comment is that it would be good with more references in the blog. Firstly, because it makes it possible for the interested reader to go to the sources and thereby be able to evaluate the information. Secondly, when no references are given the reader will not know what are "established facts", what are your own proposals, and what are hypotheses put forward by other researchers.

Anyway, again, thanks for your blog!

Per Alm 


Thanks to Per Alm both for his comments here as well as his writings which have inspired and informed many of the posts in this blog.  He has anticipated some of the topics I intended to address in future posts as well as offering some stimulating thinking regarding new directions for this blog.  

A comment under the post "Direct/Indirect Pathways and Fluency" by an individual suggests that there are subgroups who are impervious to D2 blocker treatments.  So a future post will address this issue.

The possible existence of subgroups may dilute the results of any tests for the efficacy of drug treatments and I'm currently thinking of an approach to drug testing to reduce this dilution.

There is some empirical evidence that parts of the brain outside the basal ganglia may have an impact on fluency, and this issue will be addressed in a future post.

I chose to eliminate references in the posts to avoid their becoming too ponderous.  My objective was to restrict posts to within one typewritten 8-1/2 by 11 inch page (this post excluded) for reasons that I will explicate in a subsequent post.  The intent is to provide a single post in the future that will contain many of the references that I used ranging from website entries to medical journal articles and texts.


Anonymous said...

hi its me again from the last post on drug experimenting.

I am currently trying diazepam for a few days jus to see if it has any effect. Like i said the antipsychotics had no influence on me, but i am someone who is greatly helped by small intakes of alcohol so interested to see if the diazepam helps, and if it gets me through a job interview then all the better.

thanks again for your blog.

stutter-mind-body said...

Diazepam may act to relieve some anxiety. We have previously discussed the negative effects of anxiety on fluency by way of the ventral striatum.

It's not clear though that diazepam (or any BZ) would have an effect on the root cause of your disfluency since you indicated a lack of responsiveness to dopamine D2 antagonists.

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