There are plenty of theories of what causes tinnitus. To make a general
sweeping statement about the cause of tinnitus is that it is generally
believed that tinnitus is a result of some sort of abnormality
in the auditory system due to aging, hearing loss, tumor, etc.
Usually this abnormality does not cause any serious problems for
the person except that there is an imbalance of neural signal being
sent up the auditory pathway. The brain doesn't know what to do with
these abnormal firings and interprets it as noise which you hear as
a buzzing or white noise.
Tinnitus can be divided in two two major categories objective and
objective tinnitus - is noise that can be heard by other humans.
An example is that sometimes your body noise, blood flow, heart beat,
can be perceived as abnormally loud by someone.
subjective tinnitus - is noise that can only be heard by the
person who has the tinnitus. This is what is theorized to be caused
by the abnormal neural firing that is interpreted by the brain as noise.
Is can be of different pitches or types of broad band noise. This type of
tinnitus is usually classified in a clinical evaluation by a frequency
match and intensity match to external tones, although it does not mean it
is a different "type".
I have not heard of probe mics picking up sub tinn but it could be
possible to measure obj tinn in the ear canal.
Now what could measure
(and what you might have been reading about)
in the ear canal with a probe mic are
otoacoustic emissions. These are tonal echoes that are emitted from the
cochlea usually in response to clicks and tones but have also been known
to occur spontaneously. They have been used as an indicator of normal
cohlear function and are not related to tinnitus.
Robert Adams (rwadams at ma.ultranet.com) wrote:
> Recently I have discovered that there are versions of Tinitus
> that cause the perception of "white noise" rather than a single
> tone. What is the physical explanation for this? I know that some
> research has suggested that a probe microphone can actually
> pick up the sound of tone-like tinitus in the ear canal. Does this
> also apply to noise-like Tinitus?
> Bob Adams
Thank you for your support,
dybala at utdallas.eduhttp://www.utdallas.edu/~dybala