Subject: Re: Tinnitus and a dip in the audiogram From: Bastian Epp <bepp@xxxxxxxx> Date: Mon, 10 Sep 2012 09:13:57 +0200 List-Archive:<http://lists.mcgill.ca/scripts/wa.exe?LIST=AUDITORY>--_000_504D948C9040205elektrodtudk_ Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Hi Mark, list, Even though not being an expert in tinnitus myself (but recently got attrac= ted to it), I think I could add two pieces of information here: - There is this (pretty fantastic) paper: Kujawa, S. G., and Liberman, M. C. (2009). "Adding insult to injury: cochle= ar nerve degeneration after temporary noise-induced hearing loss," J. Neurosci. 29, 14077-14085. that shows that there might be a connection between noise trauma, (not easi= ly detectable) hearing loss and tinnitus. Some of these implications will p= robably also apply once the damage is more severe. Based on this paper we d= id a study that indicates also implications for supra-threshold hearing (Ep= p et al., J. Acoust. Soc. Am. 132 (3), EL196 ). You might also want to chec= k out the references...they might aim at what you are looking for. - You idea about the dip in the audiogram: Depending on the level you see i= n the audiogram, this might indeed be an "artifact" of the poor frequency r= esolution of audiograms, neglecting fine structure effects when assessed wi= th pure tones. SOAEs are also (always) associated with a region of high sen= sitivity (i.e. up in the audiogram) - but they are most likely not a source= of tinnitus. If you mean by "dip" a poor sensitivity, then there might be = what is being discussed as "deafferentiation" going on (see above) - with i= mplications still to be clarified. The distinction between a hearing loss and masking by you tinnitus as the s= ource of the dip in the audiogram is hard to define: The audiogram defines = your ability to detect a tone - testing the whole auditory pathway rather t= han just parts of it. So by definition it is some kind of hearing loss if y= ou can't detect a tone close to your tinnitus...no matter what the reason i= s. These just as some additional thoughts All the best Bastian On 09/09/12 11:09, Mark Fletcher wrote: Hello everyone, I've noticed that tinnitus researchers often talk about the frequency of ti= nnitus being at a dip in the audiogram (in some people). It's then said tha= t tinnitus, therefore, occurs at the frequency of a hearing loss. Even if I= could be said to have an area of expertise, tinnitus research wouldn't be = it, but it's certainly an area of interest for me and I am someone with tin= nitus who has done several audiograms. On my audiogram there is a dip aroun= d the frequency of my tinnitus, but I suspect this dip is due to masking of= the tone or warble used rather than necessarily being indicative of a hear= ing loss. I'd be very interested to know how people make the distinction be= tween masking by tinnitus and a hearing loss. Many thanks, Mark Fletcher Institute of Hearing Research, Nottingham --_000_504D948C9040205elektrodtudk_ Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html> <head> =20 <title></title> </head> <body bgcolor=3D"#ffffff" text=3D"#000000"> Hi Mark, list,<br> <br> Even though not being an expert in tinnitus myself (but recently got attracted to it), I think I could add two pieces of information here:<br> <br> - There is this (pretty fantastic) paper:<br> <br> Kujawa, S. G., and Liberman, M. C. (2009). “Adding insult to injury: cochlear nerve degeneration after<br> temporary noise-induced hearing loss,” J. Neurosci. 29, 14077&#= 8211;14085.<br> <br> that shows that there might be a connection between noise trauma, (not easily detectable) hearing loss and tinnitus. Some of these implications will probably also apply once the damage is more severe. Based on this paper we did a study that indicates also implications for supra-threshold hearing (Epp et al., J. Acoust. Soc. Am. 132 (3), EL196 ). You might also want to check out the references...they might aim at what you are looking for.<br> <br> - You idea about the dip in the audiogram: Depending on the level you see in the audiogram, this might indeed be an "artifact" of the poor frequency resolution of audiograms, neglecting fine structure effects when assessed with pure tones. SOAEs are also (always) associated with a region of high sensitivity (i.e. up in the audiogram) - but they are most likely not a source of tinnitus. If you mean by "dip" a poor sensitivity, then there might be what is being discussed as "deafferentiation" going on (see above) - with implications still to be clarified. <br> <br> The distinction between a hearing loss and masking by you tinnitus as the source of the dip in the audiogram is hard to define: The audiogram defines your ability to detect a tone - testing the whole auditory pathway rather than just parts of it. So by definition it is some kind of hearing loss if you can't detect a tone close to your tinnitus...no matter what the reason is.<br> <br> These just as some additional thoughts <br> <br> All the best<br> <br> Bastian<br> <br> <br> <br> <br> On 09/09/12 11:09, Mark Fletcher wrote: <blockquote cite=3D"mid:17162_1347182628_504C6024_17162_206_1_BLU162-W458378857AD737C3= 5ABAB3D7AD0@xxxxxxxx" type=3D"cite"> <style><!-- .hmmessage P { margin:0px; padding:0px } body.hmmessage { font-size: 10pt; font-family:Tahoma } --></style> <div dir=3D"ltr"> <p class=3D"MsoNormal">Hello everyone,</p> <p class=3D"MsoNormal"><span style=3D"font-size: 10pt;"><br> </span></p> <p class=3D"MsoNormal"><span style=3D"font-size: 10pt;">I've noticed that tinnitus researchers often talk about the frequency of tinnitus being at a dip in the audiogram (in some people). It's then said that tinnitus, therefore, occurs at the frequency of a hearing loss. Even if I could be said to have an area of expertise, tinnitus research wouldn't be it, but it's certainly an area of interest for me and I am someone with tinnitus who has done several audiograms. On my audiogram there is a dip around the frequency of my tinnitus, but I suspect this dip is due to masking of the tone or warble used rather than necessarily being indicative of a hearing loss. I'd be very interested to know how people make the distinction between masking by tinnitus and a hearing loss.</span></p> <p class=3D"MsoNormal"><br> </p> <p class=3D"MsoNormal"><span style=3D"font-size: 10pt;">Many thanks,</spa= n></p> <p class=3D"MsoNormal"><span style=3D"font-size: 10pt;"><br> </span></p> <p class=3D"MsoNormal"><span style=3D"font-size: 10pt;">Mark Fletcher</sp= an></p> <p class=3D"MsoNormal"><st1:place style=3D"font-size: 10pt;"><st1:placety= pe>Institute</st1:placetype> of <st1:placename>Hearing</st1:placename></st1:place><span style=3D"font-size: 10pt;"> Research, </span><st1:place style=3D"font-size: 10pt;">Nottingham</st1:plac= e></p> </div> </blockquote> <br> </body> </html> --_000_504D948C9040205elektrodtudk_--