There is no stuttering brain?

nlieckfeldt | 21.07.2014

The Oxford Dysfluency Conference which ended yesterday started off with a presentation by Prof SE Chang from the University of Michigan talking about her findings of "Subtle differences in brain network connectivity in children who stutter".

Now, to understand that, you'd first have to appreciate the enormous achievement of making 90 children, some as young as 3 years, lay still in an MRI scanner. If you've ever been in an MRI scanner you'll know that movement of a few millimetres either way can invalidate the readings. It takes about 40mins per reading, and it’s quite noisy so potentially very scary and very boring for the children who have to be awake and alert. She and her team managed with a significant amount of pre-scan work desensitising the children to the sudden loud noises, and hand-holding during the scan. And videos!

This research is important because without it we wouldn’t know if the previously observed differences in the brains of young adults and adults who stammer are the potential cause of stammering, or merely the way the brain adapts to many years of stammering.

Just as in studies with older people who stammer, Professor Chang has found significant differences in the amount and structure of white matter in certain part of the brain that connect different regions which are essential for an effective delivery of speech. White brain matter is the 'cabling network' that allows different regions of the brain to relay information between each other and coordinates them.

To me, this seems to finally settle the question whether we stammer because our brains are different, or whether our brains are different because we stammer. It also opens up the way for new forms of therapy, yet to be developed, which may combine speech therapy with rehabilitation methods which encourage the development of neural connections.

I was particularly interested in her message to people who stammer who find the idea that their brains are different difficult to adjust to. It can sound like we’re ‘abnormal’, or it can sound like stammering is an unavoidable fate and nothing can be done, none of which are true.

My feeling has always been that these differences are very subtle, and in the normal range of brain differentiation – perhaps in the same way that some people are really good at spatial awareness while others aren’t. If this difference were in regions of our brain that control less complex functions (eg walking) I suspect no-one would ever notice the difference, but because speaking is the most complex function the brain needs to fulfil, even subtle differences can have a significant and noticeable impact.

Professor Chang agreed, but added the following two comments: the difference we have seen are differences in the brain matter relating to connectivity between regions of the brain. Speaking as a brain function is heavily reliant on the smooth cooperation between a significant number of regions of the brain so is especially susceptible to disruption. And she made it clear that these are group findings, not individual ones. It is simply not possible with current technology to look at a brain of a single child, or a single adult, and determine whether that person stammers or not. However, even today she states that individual results from boys (not girls) who stutter showed values that were entirely different from the control group and may possibly be used in future to reliably identify stammering in a child. Professor Chang urges caution but hopes to have results soon.