Subject: Re: Hearing Loss "False Positive" From: Kevin Austin <kevin.austin@xxxxxxxx> Date: Tue, 28 Sep 2010 20:22:16 -0400 List-Archive:<http://lists.mcgill.ca/scripts/wa.exe?LIST=AUDITORY>--Boundary_(ID_ufYiZgwGgPrflbRRYwQfPg) Content-type: text/plain; charset=us-ascii Content-transfer-encoding: 7BIT I did a quick, very unscientific test in a class the other day (about 30 - 35 students age mostly 19 - 22). It's done this way. Step One I whisper to the class. I whisper, if you can hear this put up your right hand. I repeat it a few times, slowly getting louder. The hands start to go up. A few don't go up. Step Two I have the class hold their pinna hard back against the sides of their head. I repeat the whisper, slowly increasing my level. It takes longer for hands to go up, but I am starting to watch for the 'late risers'. This is in the course of a demonstration about a function of the pinna. Step Three The class hold the pinna away from their heads. I repeat the whisper slowly increasing the level. I am now watching the late risers more closely. Step Four The class cup their hands behind their pinna. I start the whisper at a lower level. The hands continue to go up in about the same order as in the previous steps. At the end of this, I speak the phrase. All hands go up. There were 5 or 6 whose hands did not go up during steps 1 - 4. I asked the class if any of them were aware of having hearing loss, around 5 put up their hands. (Not completely the same ones as seen before.) I have done this in various ways over the years in many classes. Some students just don't want to participate, but based on my current very unscientific, very informal 'test', I place the figure at around one in five or one in six; 15-20%. From my experience with a 'general public' in their teens and 20s, I think this percentage is lower than found in the general population. That's my estimate. But this is also why I came to professionals with the question in the first place, one week ago today. >> Would anyone in the professional community care to comment on this? >> >> Begin forwarded message: >> >> A new study from the University of Minnesota says that we're overestimating the amount of teens with hearing loss. >> >> http://www1.umn.edu/news/news-releases/2010/UR_CONTENT_254452.html My interpretation of the response from this list, and three other local and international lists is that there is a deep underlying concern that is surfacing. I had asked similar questions a decade ago and barely got a murmur. Kevin +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ On 2010, Sep 28, at 5:45 PM, Jeffrey Willson wrote: > Okay then, bottom line, what's your estimate of the percentage of teenagers who actually have a measurable and persistent noise-induced high-frequency hearing loss? > > Jeffrey > > On Tue, Sep 28, 2010 at 8:14 AM, Torben Poulsen <tp@xxxxxxxx> wrote: > Dear List, > > Thanks to Al for a clear explanation and 'calm down' statement. > I can add to things > > 1) In the audiometry standard ISO 8253-1 'Basic pure tone audiometry' an example is given for the uncertainty: "The expanded measurement uncertainty is evaluated for the determination of the hearing threshold level of a test subject using air conduction audiometry at a frequency below 4 kHz without masking and assuming that the requirements on ambient noise are met and that no further uncertainty contribution arises from any other > sources. The uncertainty budget then has a form as presented in Table A.2. > ---I omit the table ---. The result is: Combined standard uncertainty: u = 4,9 dB. > Expanded measurement uncertainty for 95 % coverage probability, rounded to the nearest full decibel: U = 10 dB." > In other words there is a 10 dB uncertainty in the measurements itself - for frequencies below 4 kHz. The uncertainty will increase at higher frequencies (e.g. 4, 6, and 8 kHz) > > 2) It is well known that a fake hearing loss is often seen at 6 kHz when thesholds are determined with a Telephonics THD39 or THD49 earphone. This 'hearing loss' is about 5 dB and is possibly caused by an error in the reference value for audiometer calibration (for this specific earphone). This is mentioned as one of the conclusions in the Schlauch & Carney paper that the UMNews refer to. > > Regards > Torben > --Boundary_(ID_ufYiZgwGgPrflbRRYwQfPg) Content-type: text/html; charset=us-ascii Content-transfer-encoding: quoted-printable <html><head></head><body style=3D"word-wrap: break-word; = -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; = "><div>I did a quick, very unscientific test in a class the other = day (about 30 - 35 students age mostly 19 - 22). It's done this = way.</div><div><br></div><div>Step One</div><div>I whisper to the class. = I whisper, if you can hear this put up your right hand. I repeat it a = few times, slowly getting louder. The hands start to go up. A few don't = go up.</div><div><br></div><div>Step Two</div><div>I have the class hold = their pinna hard back against the sides of their head. I repeat the = whisper, slowly increasing my level. It takes longer for hands to go up, = but I am starting to watch for the 'late risers'. This is in the course = of a demonstration about a function of the = pinna.</div><div><br></div><div>Step Three</div><div>The class hold the = pinna away from their heads. I repeat the whisper slowly increasing the = level. I am now watching the late risers more = closely.</div><div><br></div><div>Step Four</div><div>The class cup = their hands behind their pinna. I start the whisper at a lower level. = The hands continue to go up in about the same order as in the previous = steps.</div><div><br></div><div>At the end of this, I speak the phrase. = All hands go up.</div><div><br></div><div>There were 5 or 6 whose hands = did not go up during steps 1 - 4. I asked the class if any of them were = aware of having hearing loss, around 5 put up their hands. (Not = completely the same ones as seen before.)</div><div><br></div><div>I = have done this in various ways over the years in many classes. Some = students just don't want to participate, but based on my current very = unscientific, very informal 'test', I place the figure at around one in = five or one in six; 15-20%. =46rom my experience with a 'general public' = in their teens and 20s, I think this percentage is lower than found in = the general population. That's my estimate.</div><div><br></div><div>But = this is also why I came to professionals with the question in the first = place, one week ago today.</div><div><br></div><div></div><blockquote = type=3D"cite"><div></div></blockquote><blockquote = type=3D"cite"><blockquote type=3D"cite"><div>Would anyone in the = professional community care to comment on this?<br><div><br><div>Begin = forwarded message:</div><br class=3D"Apple-interchange-newline"><div><div = style=3D"margin-top: 0px; margin-right: 0px; margin-bottom: 0px; = margin-left: 0px; ">A new study from the University of Minnesota says = that we're overestimating the amount of teens with hearing = loss. </div><br><a = href=3D"http://www1.umn.edu/news/news-releases/2010/UR_CONTENT_254452.html= ">http://www1.umn.edu/news/news-releases/2010/UR_CONTENT_254452.html</a><b= r></div></div></div></blockquote></blockquote><div><br></div><div><br></di= v><div>My interpretation of the response from this list, and three other = local and international lists is that there is a deep underlying concern = that is surfacing. I had asked similar questions a decade ago and barely = got a = murmur.</div><div><br></div><div><br></div><div>Kevin</div><div><br></div>= <div>+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++= ++++++</div><div><br></div><br><div><div>On 2010, Sep 28, at 5:45 PM, = Jeffrey Willson wrote:</div><br = class=3D"Apple-interchange-newline"><blockquote type=3D"cite">Okay then, = bottom line, what's your estimate of the percentage of teenagers who = actually have a measurable and persistent noise-induced high-frequency = hearing loss?<div><br></div><div>Jeffrey<br><br><div = class=3D"gmail_quote"> On Tue, Sep 28, 2010 at 8:14 AM, Torben Poulsen <span dir=3D"ltr"><<a = href=3D"mailto:tp@xxxxxxxx">tp@xxxxxxxx</a>></span> = wrote:<br><blockquote class=3D"gmail_quote" style=3D"margin:0 0 0 = .8ex;border-left:1px #ccc solid;padding-left:1ex;"> Dear List,<br> <br> Thanks to Al for a clear explanation and 'calm down' statement.<br> I can add to things<br> <br> 1) In the audiometry standard ISO 8253-1 'Basic pure tone audiometry' an = example is given for the uncertainty: "The expanded measurement = uncertainty is evaluated for the determination of the hearing threshold = level of a test subject using air conduction audiometry at a frequency = below 4 kHz without masking and assuming that the requirements on = ambient noise are met and that no further uncertainty contribution = arises from any other<br> sources. The uncertainty budget then has a form as presented in Table = A.2.<br> ---I omit the table ---. The result is: Combined standard uncertainty: u = =3D 4,9 dB.<br> Expanded measurement uncertainty for 95 % coverage probability, rounded = to the nearest full decibel: U =3D 10 dB."<br> In other words there is a 10 dB uncertainty in the measurements itself - = for frequencies below 4 kHz. The uncertainty will increase at higher = frequencies (e.g. 4, 6, and 8 kHz)<br> <br> 2) It is well known that a fake hearing loss is often seen at 6 kHz when = thesholds are determined with a Telephonics THD39 or THD49 earphone. = This 'hearing loss' is about 5 dB and is possibly caused by an error in = the reference value for audiometer calibration (for this specific = earphone). This is mentioned as one of the conclusions in the Schlauch = & Carney paper that the UMNews refer to.<br> <br> Regards<br> Torben<br><br></blockquote></div></div> </blockquote></div><br></body></html>= --Boundary_(ID_ufYiZgwGgPrflbRRYwQfPg)--