Jinx wrote:

> The same technique used to relieve tinnitus.  The patient is fed white
> noise, which they soon become used to and ignore. As the volume of the
> white noise is gradually reduced over a period of time, it "takes" the
> tinnitus with it as the patient's auditory system adjusts

  One version of it.  The one I seem to recall is that they are actually
fed "pink" (possibly "ochre" or "lime" really) noise matched to the
tinnitus so that it provokes the brain to ignore that frequency (notch).

  Tinnitus (which I have due to a diving _faux pas_) is not necessarily
a pure tone - if one (or a few adjacent) nerve cells are damaged and
fire spontaneously (though apparently the same effect happens if they
are damaged and therefore do *not* fire at all), they do not directly
map to frequency, pure tone mapping requires post-processing contrast
enhancement further on in.  Thus "pink" noise counter-stimulus is more
appropriate than a pure tone.

  Also, tinnitus usually self-cancels (mine does, unless you remind me
of it), implying that severe persistent tinnitus requiring masking
devices is actually a breakdown in the brain, not the ear. Thus treated
with anti-epileptic, anti-psychotic or antidepressant medication.

  Speaking from personal observation, I believe everybody knows what
tinnitus is because everyone gets it.  Can anyone tell me they never
have experienced a sudden "airy" whistle in their hearing which they
knew was spurious, but which faded away in a minute or so and was
forgotten.  This could signal the random, spontaneous demise of a
neurone somewhere in the system, just like the sharp spurious pain in a
limb or other body part and similar in other senses.  Alternatively, it
may not be actual neurone death, but a localised, trivial, epileptiform
phenomenon.
--
  Cheers,
        Paul B.