Tuesday, August 16, 2011

Auditory-motor integration in different part of brain?

Martin Sommer's team has published new results on their TMS experiments. Martin's student Nicole Neef presented results at the Oxford Dysfluency Conference three years ago on that same topic.The big issue with TMS is that you need to aim correctly to ensure that you "magnetically" knock out the targeted regions. I am somewhat puzzled what more they found. I would have to dig out the paper to see what has now changed to warrent an Elsevier press release. They claim that they have found further evidence that auditory-motor integration is located in a different part of the brain, because TMS has the reverse effect on people who stutter. Such a profound re-organisation is probably the effect of some neurobiological abnormality arising in early childhood.

As a footnote, you might notice that Alexander Wolff von Gudenberg is an author of the article. He is the boss of the Kassel Stuttering Therapy, and I introduced Martin to him with the aim to give Martin plenty of experimental subjects for his experiments. They regularly put clients into a bus and drive them up to Goettingen with their will [as opposed to "against their will"]. So delivering brains for research gives you co-authorship!

Here is the published summary:
..The dramatic but short-lived effect of hiding the sound of one's own speech indicates that the integration of hearing and motor functions plays some role in the fluency (or dysfluency) of speech. New research has shown that in adults who have stuttered since childhood the processes of auditory-motor integration are indeed located in a different part of the brain to those in adults who do not stutter... Dr. Nicole Neef and Dr. Martin Sommer from the University of Goettingen, together with Dr. Bettina Pollok from the University of Duesseldorf, studied the performance of a group of adults who stutter, as well as a control group of adults who do not stutter, in a finger tapping exercise. They used Transcranial Magnetic Stimulation (TMS) to interfere temporarily with brain activity in the dorsolateral premotor cortex while the participants tapped their fingers in time with the clicks of a metronome. In control subjects, disturbing the left premotor cortex impaired the finger tapping, but disturbing the right premotor cortex had no effect. In stuttering adults, the pattern was reversed: the accuracy of finger tapping was affected by disturbing the right hemisphere, and unaffected when disturbing the left. Previous research has already linked stuttering with a right-shifted cerebral blood flow in the motor and premotor areas during speech. In this new study, a shift of auditory-motor integration to the right side of the brain occurred even in a task not directly involving speech. Thus, in the brains of adults who stutter there appears to be a profound reorganization possibly compensating for subtle white matter disturbances in other parts of the brain - the left inferior frontal regions. These findings shed light on the extent of the reorganization of brain functions in persistent developmental stuttering.
"Right-shift for non-speech motor processing in adults who stutter" by Nicole E. Neef, Kristina Jung, Holger Rothkegel, Bettina Pollok, Alexander Wolff von Gudenberg, Walter Paulus, Martin Sommer, and appears in Cortex, Volume 47, Issue 8 (September 2011)


Norbert said...

"They regularly put clients into a bus and drive them up to Goettingen with their will. So delivering brains for research gives you co-authorship!"

Is it me or does that sound faintly disconcerting?

Tom Weidig said...

Not really, no-one is forced to participate, and I am not aware of the current practise anyway.

But fact is that finding experimental subject is a big big issue and very time consuming.

The intensive group in Kassel has 10-20 people for 2 weeks on-site. So in 1-3 trips you have all the people you need. You literally save WEEKS IF NOT MONTHS.

You are just too much health&safety&consent based, which especially in research hurts research severely. And makes it much more costly, money that could be spent for other things.

Norbert said...

"You are just too much health&safety&consent based,"

Am I? I didn't know....

So, why do people need to make their Will to go to Goettingen?

It's also an interesting point if an intensive course is a place to look for consent for this. There's certainly an issue with peer pressure etc - it's just better to get people to be informed, and happy to say 'yes' rather than having them (as they might) afterwards tell others "I didn't really want to go but didn't feel I could say no".

Anonymous said...

I think this is standard practice finding subjects in general.

Martin Sommer said...

Dear all,

thanks for commenting on our article.

With regard to the presumed bus transfer, it does not take place. We do the experiments on site in Kassel. We transfer the recording equipment to their therapy centre.

Other studies are taking place here in Goettingen, with local people or people willing to travel here.

Everybody can say no (not so few do, by the way).

I hope this helps and dispels some doubts.

Best regards,

Martin Sommer

Tom Weidig said...

Thanks for the clarification! I would like to add that that is what I was told a few years ago.

TMS experiments are more mobile, and so the researcher can travel to the subjects. So getting to Kassel is much easier.

However, with brain imaging studies that is not possible, and there you need to go the scanner. So taking the mini-bus from the therapy is the best option.

I also want to say that I regard it as a duty that people who stutter should participate. If they want therapy, they should also give some of their time.

Tom Weidig said...

Norbert, I think there is a misunderstanding here.

I meant "with their will" as word play on "against their will.

I did not imply that they need to take their will because they are in danger or anything....

In my experience, everyone is very happy to participate and trying to help researchers.

Anonymous said...

Martin, are you a stammerer? How severe is your stammering???