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Re: Technique can pinpoint tinnitus

The idea of the relationship between some measure from OAEs and
tinnitus is still progressing. Recently, Glenis Long and Lucas Parra
(and co-authors, sorry) gave very convincing evidence that even the
spectral profile of tinnitus, i.e. a tinnitus likeness spectrum, can
be predicted by measures of a high resolution audiogram and the growth
of DPOAE as a function of level. This was true for a subset of their
tinnitus sufferers, particularly those who have stable tinnitus.

However, remember that, as pointed out earlier by Arnaud in this
thread, people who have their 8th nerve resected (for surgical
resolution of a vestibular schwannoma, typically) often have tinnitus.
The percentage depends a lot on which study you look at, but the point
is, you will typically get tinnitus once your cochlea is disconnected.
So OAEs won't be of much use at that point...


Didier A Depireux                depireux@xxxxxxxxx
Inst. for Systems Research    http://theearlab.org
School of Engineering           Ph: 410-925-6546
U Md College Park MD 20742 USA
Adjunct, BioEngineering

On Wed, Oct 7, 2009 at 3:43 AM, Andrew Bell <andrew.bell@xxxxxxxxxx> wrote:
> Matt and list:
> Thanks for pointer to Ceranic et al (1998), a paper which gives clear
> evidence that spontaneous otoacoustic emissions (SOAEs) and tinnitus are
> closely related. If SOAEs sound like tinnitus and behave like tinnitus,
> isn't it likely that they are (in some respect) tinnitus?
> If we are aiming to pinpoint tinnitus, then SOAEs offer the most direct
> tool, and Ceranic et al. support this idea. Their Table 5 shows that
> patients with head injury and tinnitus displayed 4.4 SOAEs per ear, compared
> to 1.7 with normals and 0.25 with those having head injury without tinnitus.
> So did the head injury damage the cochlea and generate a tinnitus sensation
> (via afferent pathways), or did the injury damage the brain, which responded
> by sending a signal to the cochlea (via efferent pathways)? As you say, that
> question is still very much open, but it would definitely repay some
> attention.
> Andrew.
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> Andrew Bell
> Research School of Biology (RSB)
> The Australian National University
> Canberra, ACT 0200, Australia
> T: +61 2 6125 5145
> F: +61 2 6125 3808
> andrew.bell@xxxxxxxxxx
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>> Further, tinnitus can also be induced by head injury [6]. In
>> this case, it is possible that the inner ear is damaged and
>> this causes a peripheral type of tinnitus, which again is a
>> cochlear amplifier dysfunction. Until we can successfully
>> trace this cause and develop methods such as cellular
>> regeneration possibly using stem cells - we can tinker and
>> experiment using all sorts of procedures to quash the
>> problem, but they will never be as sophisticated as actually
>> repairing the biology.
>> [6] @ARTICLE{ceranic:1998,
>>   author = {Ceranic, B.J. and Prasher, D.K. and Raglan, E.
>> and Luxon, L.M.},
>>   title = {{Tinnitus after head injury: evidence from
>> otoacoustic emissions}},
>>   journal = {Journal of Neurology, Neurosurgery \& Psychiatry},
>>   year = {1998},
>>   volume = {65},
>>   pages = {523--529},
>>   number = {4},
>>   publisher = {BMJ}
>> }