jueves, 17 de febrero de 2011

Acúfenos: Sección nuevos tratamientos. Estimulacion del nervio vago

Tinnitus expert Barry KeateASK BARRY
Tinnitus expert, Barry Keate, 

Vagus nerve "cure" for tinnitus?
Dear Barry,
I have just read a news item in my daily paper concerning VNS treatment for tinnitus. Apparently it works by stimulating a nerve in the neck.
Scientists at the University of Texas bombarded rats with various frequencies of sound to retrain their brains, eliminating the tinnitus. 

They say it is like pressing a reset button in the brain.
What are your thoughts on this treatment, please? Is it similar to Tinnitus Retraining Therapy, which I have tried, with a far amount of success, I might add? 

The thing is, I would still like to get rid of the ringing for good, and experience complete silence again.
I live in London, and wonder when this treatment might become available.
Yours sincerely,
Andrea R.

Dear Andrea,
A report published online in the journal Nature on January 12, 2011 purports to show that tinnitus can be cured, or at least significantly reduced, in laboratory rats through Vagus Nerve Stimulation (VNS). 

The vagus nerve reaches from the brain to the abdomen. Researchers electrically stimulated the vagus nerve while exposing the rats to a variety of sound tones over an extended period of time. At the end of the study, rats who experienced both the electrical stimulation and the sound tones appeared to overcome their tinnitus while rats who only had the electrical stimulation or the sound tones, but not both, did not recover.

The rationale for this treatment method makes sense. Researchers believe that the brain changes in response to nerve damage or cochlear trauma. The auditory cortex delegates too many neurons to the frequencies where there is hearing loss. 

These neurons become overexcited and cause the phenomenon known as tinnitus.
By stimulating the vagus nerve electrically, the auditory cortex seems to be able to reconstruct and reorganize itself by neuronal plasticity. 

The addition of the sound tones, which are presumable different from the tinnitus sounds, stimulates the auditory cortex at frequencies other than tinnitus and retrains the brain to become more synchronous and regulated.

There are several potential setbacks to this therapy and only time will tell how effective it may be. Currently, VNS therapy is used successfully for intractable epilepsy and treatment resistant depression.

It is accomplished by means of an implantable electronic device, much like a heart pacemaker, that powers electrodes connected to the vagus nerve. In the future, less invasive power supplies and electrodes will probably be used.

Another thing to consider is that there are many successful experiments in animal models that simply don't pan out when they are applied to humans. Electrical stimulation for the relief of tinnitus is nothing new.

In fact, there are several applications of this from cochlear implants, which are implanted electronic devices, to electrodes implanted directly into the auditory cortex.

VNS appears similar to using a Transcutaneous Electrical Nerve Stimulator that we discussed in Somatic Tinnitus. It's purpose is to stimulate the dorsal cochlear nucleus. This article can be seen here
No matter what the outcome, it will be several years before we know how well this treatment may work. 

Then there will be more time needed to refine the procedure.

When cochlear implants were first introduced, it was another 10 years before they were refined to the point they could become implanted.

So we don't know how this will work in the end, however there is much good work being done by fine researchers such as these.

Wishing you quiet times,
Barry Keate
Fuente : Quiet Times 02/11

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