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Deaf Brain: Auditory Regions Convert to a Sense of Touch

brain.jpgVirginia Commonwealth University School of Medicine researchers did some research on ferrets. They discovered that deaf ferrets re-routed the sense of touch into parts of the brain usually intended for hearing.

This study is published in the Early Edition of the Proceedings of the National Academy of Sciences (March 23, 2009). The team reported a phenomenon known as cross-modal plasticity in the auditory system of adult animals.

In medical terms, cross-modal plasticity means that a damaged sensory system in the brain has been replaced by another sensory system. In this case, in the parts of the brain reserved for a sense of hearing has been replaced with touch.

“One often learns, anecdotally, that ‘grandpa’ simply turned off his hearing aid because it was confusing and no longer helped. Our study indicates that hearing deficits in adult animals result in a conversion of their brain’s sound processing centers to respond to another sensory modality, making the interpretation of residual hearing even more difficult,” said principal investigator Alex Meredith, Ph.D., a professor in the VCU Department of Anatomy and Neurobiology.

Note! Hearing parts of the brain are rewired to a sense of touch! It is also said, "these findings raise the possibility that even mild hearing loss in adult humans can have serious and perhaps progressive consequences", thus if you're going to give someone auditory input they will still be at a state (in medical terms) that is more than a mild hearing loss. And thus the likelihood of a rewired brain, that dominates via touch. So next time some sadistic hearing person tries to shove a copious amount of say AVT, they might want to consider giving the deaf person a brain implant first. CIs are just not going to be enough to make us normal.

Source:
Adult deafness induces somatosensory conversion of ferret auditory cortex
Researchers Studying Hearing Loss in Adult Animals Find that Auditory Regions of the Brain Convert to the Sense of Touch

See also:
Cochlear Implants prevent 'scrambling' in deaf brains

Photo credit: Gaeten Lee

Comments (27)

Don't tell Rachel of cochelarimplantoneline.com. She will have a fit a demand to see your sources! Never mind that u ahve linked to them.

I totally need a brain implant too! I'm not normal after all, those pesky over developed touch pathways are and abnormality since they don't fall within in a median. (Nevermind the fact that could lead to deaf people being better lovers).

Since all the fault is with me, and my abnormality; who's developing a brain implant, since a CI would just leave me shortchanged? And my only way to fit into society and be normal. Anyone?

There has to be a money spinner in this. Has the url brainimplantonline.com been snapped up yet?

This is one of the reason that implants don't work well in adults who have been profoundly deaf their whole lives. If the brain doesn't use the auditory processing center for hearing, it uses it for something else.

This is a big reason why parents need to give their children the implant early, if they choose to go with the implant. Waiting until they are old enough to make that decision for themselves simply doesn't work. Their brains will probably not be able to make sense of sound by the time they are old enough to decide. The rewiring takes time, and it hasn't happened yet for babies and toddlers.

@KL - note the research is quoting old people / adults with a mild hearing loss too, and the consequences on the brain. (See press release).

Thus if its having an impact brain wise, on previously hearing people (as adults) with just a mild loss; then there's a lesson there.

Unfortunately, there's some nutters out there who expect a profoundly deaf child to suddenly be hearing. The maths really doesn't add up.

This looks like another bullet in the AVT weaponery: ferrets remap their sense of touch to unused auditory parts of their brain.

We probably will be seeing AVT professionals argue that sign language must be excluded for fear it will take up precious room in the auditory cortex.

Grandpa probably will be told not to use his eyes or his hands so that his hearing aid can continue to access his hearing brain cells.

This needs to be proven first before it can be argued. Also needs to be proven that we use auditory cortex for visual purposes or even for language in its various forms. What a debacle this will turn out to be.

@ KL are you really that DESPERATE to justify the implant? Why is it so common for implantee advocates to scrape the bottom of the barrel to support the implant? I did a double take when I re-read your response to the post and commentary. So you get all this hearing, but do u acquire any ability to think, reason, and deduce along the way?

Hi Tony. In answer, yes. You do get the ability to think, reason and deduce along the way. It is not speech therap, it is language therapy. And please note, I'm not talking about AVT. I'm talking about therapy in general. The brain structures are "built" in the first three years of life. That is when the brain is most "plastic", and can make the most and strongest neural pathways. No matter if the child is born deaf or hearing, it is capable of learning verbal language and sign language (and/or both) best if started early.

So...... you are still IGNORING the wider ramifications of what this study throws up, to support the oralist early intervention mantra. I've read similar arguments like this before.

Besides we ALREADY KNOW that early intervention is necessary with kids, HOWEVER studies like this will only be read one way by the oralist/ implantee camp.

No prizes for guessing, but that's how I read your response.

Tony,
The wider ramifications are simply that the brain uses all the space available to it. If an area of the brain is left unused for its original purpose, the brain will use it for some other purpose. Like a room in a house. If it was supposed to be a bedroom, but nobody sleeps there, is it left empty or is it used for something else? It gets turned into a sewing room, or computer room or office or something else.

If the hearing/auditory center of the brain is not used for making sense of sound, it will be used for something else. If you want to keep the auditory center active as an auditory center, then you better get sound into the brain as soon as possible.

But surely the bodies ability to use it for something else is a good thing?

So, if we start teaching ALL deaf kids sign language, then they will grow up with language etc., so yeh, early intervention is desirable. I agree. But the stumbling block is, cultural perceptions of parents and society.

I fully agree that the brain's ability to use its space for other things is good. It is great. All I am saying is that if you want usable hearing, you need to get sound in early.

We did teach our daughter sign language, along with getting an implant. She signs and speaks.

Yeh, but that's not how your original comment read tho!

How is that?

U zeroed in on the implant issue!

I found the discussion relevent to the implant issue. I didn't realize that wasn't allowed. Implant success or failure is mostly about how well the brain can make sense of sound. And that has everything to do with how well the brain's auditory center can be or is developed. If it is now in use for something else, it certainly won't work well for hearing comprehension anymore.

That may be, but like I said there is more to this post.. u r focussing exclusively on the implant angle. There are social and cultural ramifications at stake here. Social and cultural impositions, by which the larger society deems deafness to be "whatever" and it is imposed on us "deafies".

THAT, is what I mean by wider ramifications. THAT is what is oft ignored. There is a lot more at stake than some frigging early intervention process [important as it is]. There is more at stake than having the ability to hear or speak.

There is so much focus on getting it [whatever that it is] right on kids, that older deafies are trapped in a no man's land. People who become deafened at a later gave, have to battle not only the deafness, but also the same shitty attitudes abt deafness that we suffer as youngies.

There is so much frigging focus on getting it [whatever that it is] right on kids, that if it fails, they are left to pick up the pieces, not the hearing worldl!

There are definitely ramifications for late deafened adults. I am not one, and cannot comment to that. I only feel that I can comment on the aspects that I know about. Doesn't mean that those other ramifications are not important. They are. And the comments can carry more than one discussion at a time. I'll bow out now.

This have certainly shed some light why adult implantations aren't always successful especially for lifelong deaf person. If only some of my mates have known this before too late.

But this should not be the reason to divert onto new premise as to why therefore we ought to implant children at a young age. Granted there are valid medical reasons for early implantations especially if BTE hearing aids are rendered useless due to physiological reasons. However, I have also observed other deaf people acheiving the same results with BTE aids from birth, as do the ones with CI implants. Why the over-zealous push for CI implantations when a cheaper version will suffice? Who will profit from the mass implantation programme? The CI manufacturers - who carry the financial clout to fund medical research which will find in favour of their products and, cos the findings are recorded in the annals of medical research, it become gospel for all medical staff. The trickle-down effects of this gospel is what we are witnessing here. The undulating urge to implant all children. Sorry, it just don't sit well for some of us.

But why bow out? Is it because that was all you wanted to say? Was that the extent of your interest in deafness; the speech, hearing, the implant and early intervention? Do you not have any further interest in this issue at all? Does not the social and cultural imposition interest you? Doe snot the negative effects of that imposition warrant engaging in further debate? Or is it, as it seems, that you have said your piece, and want to bow out because of no further interest?

Hi Tony,
No, I bowed out because I felt you wanted to take the discussion into areas I feel I am not qualified to speak to. I read way more than I respond, and I like to learn about other viepoints. I only comment when I feel I have something valuable to say. I also felt that I was monopolizing the conversation, and I wanted to give other people a chance to chime in.

In answer to Saltbar, I can only say that hearing aid trials are required before anyone can be qualified to even receive an implant. If hearing aids work, the person is not qualified to get an implant. And they have to be severe to profoundly deaf also.

I'm not any more qualified to comment on the veracity of the implant, for example, but that does not mean I can't see th wider implications, so I do comment. I do, in spite of how it appears, investigate how the implant works etc., because it is important to understand the issue in a holistic way, than just certain aspects, Otherwise how do we learn.

That is precisely what th problem with deaf debate. Focus on the singular.

I am very aware that as a hearing person, I don't have the personal experience to comment on Deaf issues in general. I follow many blogs, but rarely actively participate in them. I get flamed enough when I do comment, so I am very careful to only participate when it is something I actually have direct knowledge of. That is my choice, and the only one I am comfortable with.

Kim, I understand about the flaming issue. I don't wanna take u to task over that. I do understand the fear of participating, because we feel or perceive a lack of knowledge and experience.

And yes, I too, abstain from commenting on some blogs.But the point of discussion is not just to make comments, but to ask questions. How else do we learn?

But some flamers also respond from a point of ignorance. I can pick that a mile off. Just as some commentators, bloggers, etc., write from a point of ignorance or lack of experience.

I'm not a woman, but that doesn't stop me from reading, investigating or talking about issues pertaining to women. It doesn't stop me from reading up on Feminism, biological issues, etc., because to me women are human beings, so of course it is important to try and understand THEIR perspectives. Their oppression and how it relates to other forms of oppression.

If I don;t know, I can ask.

I have no problem asking questions. But I only ask if I am willing to join the discussion in general.

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