Subject: Re: overtone tinnitus? From: Andrew Bell <andrew.bell(at)anu.edu.au> Date: Tue, 18 May 2004 10:16:39 +1000Your 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(at)anu.edu.au ~~~~~~~~~~~~~~~~~~~~~~~~~~ -----Original Message----- From: AUDITORY Research in Auditory Perception [mailto:AUDITORY(at)LISTS.MCGILL.CA] On Behalf Of Julius Verrel Sent: Monday, 17 May 2004 8:11 PM To: AUDITORY(at)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