Re: overtone tinnitus?

[Andrew Bell <andrew.bell@xxxxxxxxxx>]

Your friend’s experience is very similar to that recognised by
Urbantschitsch in his classic ‘Lehrbuch der Ohrenheilkunde’. He has a
section discussing a phenomenon called ‘Doppelthören’ (double hearing). He
gives an account of a man who went to the theatre to listen to an aria; he
thought someone was whistling along with the music only to discover it was
his own ear! (p.67, 5th edition, 1910).

Double hearing is an intriguing phenomenon, with different manifestations. I
see the tectorial membrane as a carrier of very low wave velocities (mm per
second) allowing resonance to occur between the rows of outer hair cells.
Thus, a wave velocity of 30 mm/s would give 1 kHz resonance between OHC rows
30 um apart. In this picture, the resonant system could, under circumstances
of inadequate gain control, ‘whistle along’ with the acoustic input. 

One remarkable form of double hearing, diplacusis echotica, is where the
person hears the sound and then an echo ½ to 1 second later. Neural or
cochlear explanations could be considered. In terms of outer hair cells, how
could a delay of 1 second be generated? If for some reason the wave energy
were directed along the tectorial membrane (30 mm long) instead of across
it, the wave velocity above could provide a 1 second delay.

You can reassure your friend that their experience is a documented
audiological phenomenon, but the cochlear mechanics is still in the realm of
speculation.


Andrew.

~~~~~~~~~~~~~~~~~~~~~~~~~~~
Andrew Bell
Research School of Biological Sciences
Australian National University
Canberra, ACT 2601, Australia
ph. +61 2 6125 9634
fax +61 2 6125 3808
andrew.bell@anu.edu.au
~~~~~~~~~~~~~~~~~~~~~~~~~~

-----Original Message-----
From: AUDITORY Research in Auditory Perception
[mailto:AUDITORY@LISTS.MCGILL.CA] On Behalf Of Julius Verrel
Sent: Monday, 17 May 2004 8:11 PM
To: AUDITORY@LISTS.MCGILL.CA
Subject: [AUDITORY] overtone tinnitus?

Dear all,

a friend of mine, a piano teacher, recently had a temporary "tinnitus" 
experience which I'd like to know more about (and I hope it is 
interesting for at least some of you).

It was actually temporary in a double sense: First, it fortunately 
disappeared after two days. Second, it was only present together with 
other sounds (speech, music, cars), and apparently always constituted 
one or more of the overtones of this sound. It first occured while F. 
was attending to high overtones (around c4) while a pupil of his was 
playing low notes - apparently he couldn't swich off this "attention" 
afterwards.

as far as I understand it, tinnitus usually denotes a nervous 
phenomenon, essentially independent of acoustic input. we wondered 
whether this "overtone tinnitus" was rather a very low-level 
phenomenon, maybe involving outer hair cells.

Any ideas?




--
Julius Verrel
FB Psychologie
Universität Münster
48149 Münster

Tel +251 83-34178