Subject: Re: A question about pre-natal hearing From: "Monson, Brian" <BMONSON@xxxxxxxx> Date: Tue, 3 Mar 2015 15:30:56 +0000 List-Archive:<http://lists.mcgill.ca/scripts/wa.exe?LIST=AUDITORY>--_000_AC9FEE27F1A2466082EA8E9381EC4C85partnersorg_ Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Dear List, In case it might be useful to anyone else, please see my response to Jan's = question below. Best, Brian Brian B. Monson, PhD Research Fellow | Department of Pediatric Newborn Medicine Brigham and Women's Hospital | Harvard Medical School Phone: +617 525 4131 | Email: bmonson@xxxxxxxx<mailto:vsaka= lidis@xxxxxxxx> On Mar 2, 2015, at 5:32 PM, Brian Monson <BMONSON@xxxxxxxx<= mailto:BMONSON@xxxxxxxx>> wrote: Dear Jan, Fetal hearing is certainly a complicated issue. I've seen several individu= als at conferences refer to the intrauterine environment as simply a 500-Hz= low-pass filter, which doesn't appear to be entirely accurate. Another po= int sometimes brought up is that, to a first approximation, intrauterine he= aring should mimic underwater hearing, which stimulates the inner ear prima= rily via bone conduction (Hollien, 1973, JASA, 53:1288-1295). However, I t= hink we need to be cautious about bone conduction for children and adults v= s. a fetus whose bones (including the ossicles) aren't completely ossified.= On the other hand, inner ear stimulation could occur entirely via fluid r= ather than bone (Perez et al, 2011, Hearing Research, 280:82-85). To your specific question, the middle ear of the fetus is fluid filled, whi= ch will likely dampen whatever mechanical forces the non-ossified ossicles = might provide. Further complicating the process, however, the (incompressi= ble) fluid in the middle ear would also provide another direct acoustic pat= hway from the tympanic membrane to both the oval window and round window. = Theoretically this pathway is also present via the airspace when the middle= ear is filled with air, but I suppose it typically gets ignored because th= e ossicles would dominate oval window actuation. That might not be true of = cartilaginous ossicles in a fluid-filled middle ear space. In any event, fetuses have been reported to develop sensitivity to low freq= uencies first, followed by high frequencies (Hepper & Shahidullah, 1994, "T= he development of fetal hearing"), so the question of what the cochlea pick= s up is highly dependent on the gestation time point of interest. Gerhardt= & Abrams have a review on fetal hearing that you might already have, but I= 'm attaching just in case. I hope this is helpful. I'd be interested to hear any input you might get = from others. Best, Brian Brian B. Monson, PhD Research Fellow | Department of Pediatric Newborn Medicine Brigham and Women's Hospital | Harvard Medical School Phone: +617 525 4131 | Email: bmonson@xxxxxxxx<mailto:vsaka= lidis@xxxxxxxx> On Mar 1, 2015, at 2:22 PM, Jan Schnupp <jan.schnupp@xxxxxxxx<mailto:j= an.schnupp@xxxxxxxx>> wrote: Dear List, I was looking around for literature describing the intra-uterine sound envi= ronment of unborn fetuses and came across this paper http://journals.lww.com/greenjournal/abstract/1992/08000/sound_levels_in_th= e_human_uterus.6.aspx which suggests that sound in the uterus - if measured with a hydrophone - i= s essentially unattenuated relative to the source of air born sound and sho= ws apparently no low-passing. That would suggest that sound in utero is ess= entially crystal clear and not "muffled" as one might perhaps intuitively s= uspect. However, as I was pondering this I wondered: what about the middle = ear of unborn children? Are they filled with (amniotic?) fluid? Or with air= ? And does it matter? How good could we expect the cochlea in the unborn to= be at picking up sound from the amniotic fluid, and does that depend on wh= ether the middle ear is fluid or air filled? Best wishes, Jan -- Prof Jan Schnupp University of Oxford Dept. of Physiology, Anatomy and Genetics Sherrington Building - Parks Road Oxford OX1 3PT - UK +44-1865-282012 http://jan.schnupp.net<http://jan.schnupp.net/> <Gerhardt_2000_Fetal Exposures to Sound and Vibroacoustic Stimulation.pdf> The information in this e-mail is intended only for the person to whom it is addressed. If you believe this e-mail was sent to you in error and the e-ma= il contains patient information, please contact the Partners Compliance HelpLi= ne at http://www.partners.org/complianceline . If the e-mail was sent to you in e= rror but does not contain patient information, please contact the sender and pro= perly dispose of the e-mail. --_000_AC9FEE27F1A2466082EA8E9381EC4C85partnersorg_ Content-Type: text/html; charset="us-ascii" Content-ID: <7947A41FEE4C1A4BAF3282B515117BD1@xxxxxxxx> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable <html> <head> <meta http-equiv=3D"Content-Type" content=3D"text/html; charset=3Dus-ascii"> </head> <body style=3D"word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-lin= e-break: after-white-space;"> Dear List, <div>In case it might be useful to anyone else, please see my response to J= an's question below.</div> <div>Best,</div> <div>Brian</div> <div><br> </div> <div><br> <div apple-content-edited=3D"true"> <div style=3D"color: rgb(0, 0, 0); letter-spacing: normal; orphans: auto; t= ext-align: start; text-indent: 0px; text-transform: none; white-space: norm= al; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; 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letter-spacing: normal; orphans: auto; t= ext-align: start; text-indent: 0px; text-transform: none; white-space: norm= al; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; word-w= rap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-= space;"> <div style=3D"color: rgb(0, 0, 0); letter-spacing: normal; orphans: auto; t= ext-align: start; text-indent: 0px; text-transform: none; white-space: norm= al; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; word-w= rap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-= space;"> <div style=3D"color: rgb(0, 0, 0); letter-spacing: normal; orphans: auto; t= ext-align: start; text-indent: 0px; text-transform: none; white-space: norm= al; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; word-w= rap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-= space;"> <div style=3D"color: rgb(0, 0, 0); letter-spacing: normal; orphans: auto; t= ext-align: start; text-indent: 0px; text-transform: none; white-space: norm= al; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; word-w= rap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-= space;"> <div style=3D"color: rgb(0, 0, 0); letter-spacing: normal; orphans: auto; t= ext-align: start; text-indent: 0px; text-transform: none; white-space: norm= al; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; word-w= rap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-= space;"> <span class=3D"Apple-style-span" style=3D"border-collapse: separate; color:= rgb(0, 0, 0); font-variant: normal; letter-spacing: normal; line-height: n= ormal; orphans: 2; text-align: -webkit-auto; text-indent: 0px; text-transfo= rm: none; white-space: normal; widows: 2; word-spacing: 0px; border-spacing= : 0px; -webkit-text-decorations-in-effect: none; -webkit-text-stroke-width:= 0px;"> <div style=3D"word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line= -break: after-white-space;"> <div style=3D"margin: 0in 0in 0.0001pt;"><span style=3D"color: rgb(31, 73, = 125); background-color: white;"><font face=3D"Calibri">Brian B. Monson, PhD= </font><font face=3D"Calibri, sans-serif"><span style=3D"font-size: 14px;">= <o:p></o:p></span></font></span></div> <div style=3D"font-family: Calibri, sans-serif; font-style: normal; margin:= 0in 0in 0.0001pt; font-size: 11pt;"> <br> </div> <div style=3D"font-family: Calibri, sans-serif; font-style: normal; margin:= 0in 0in 0.0001pt;"> <span style=3D"color: rgb(31, 73, 125); background-color: white; font-size:= 12px;">Research Fellow | </span><span style=3D"font-size: 12px; text-= align: -webkit-auto; color: rgb(31, 73, 125); background-color: white;">Dep= artment of Pediatric Newborn Medicine</span></div> <div style=3D"font-family: Calibri, sans-serif; font-style: normal; margin:= 0in 0in 0.0001pt;"> <span style=3D"font-size: 12px; text-align: -webkit-auto; color: rgb(31, 73= , 125);">Brigham and Women's Hospital <span style=3D"background-color:= white;">| Harvard Medical School</span></span></div> <div style=3D"font-family: Calibri, sans-serif; font-style: normal; font-we= ight: normal; margin: 0in 0in 0.0001pt;"> <span style=3D"color: rgb(31, 73, 125); background-color: white; font-size:= 12px;">Phone: +617 525 4131 | Email: <span style=3D"color: blue; = text-decoration: underline;"><a href=3D"mailto:vsakalidis@xxxxxxxx" sty= le=3D"color: blue; text-decoration: underline;">bmonson@xxxxxxxx= d.edu</a></span></span></div> <div style=3D"font-family: Calibri, sans-serif; font-style: normal; font-we= ight: normal; margin: 0in 0in 0.0001pt; font-size: 11pt;"> <br> </div> </div> </span></div> </div> </div> </div> </div> </div> </div> </div> </div> </div> </div> </div> </div> <br> <div> <div>On Mar 2, 2015, at 5:32 PM, Brian Monson <<a href=3D"mailto:BMONSON= @xxxxxxxx">BMONSON@xxxxxxxx</a>> wrote:<= /div> <br class=3D"Apple-interchange-newline"> <blockquote type=3D"cite"> <div> <div style=3D"word-wrap:break-word">Dear Jan, <div>Fetal hearing is certainly a complicated issue. I've seen severa= l individuals at conferences refer to the intrauterine environment as simpl= y a 500-Hz low-pass filter, which doesn't appear to be entirely accurate. &= nbsp;Another point sometimes brought up is that, to a first approximation, intrauterine hearing should mimic underwat= er hearing, which stimulates the inner ear primarily via bone conduction (H= ollien, 1973, JASA, 53:1288-1295). However, I think we need to be cau= tious about bone conduction for children and adults vs. a fetus whose bones (including the ossicles) aren't complet= ely ossified. On the other hand, inner ear stimulation could occur en= tirely via fluid rather than bone (Perez et al, 2011, Hearing Research, 280= :82-85).</div> <div><br> </div> <div>To your specific question, the middle ear of the fetus is fluid filled= , which will likely dampen whatever mechanical forces the non-ossified ossi= cles might provide. Further complicating the process, however, the (i= ncompressible) fluid in the middle ear would also provide another direct acoustic pathway from the tympanic membr= ane to both the oval window and round window. Theoretically this path= way is also present via the airspace when the middle ear is filled with air= , but I suppose it typically gets ignored because the ossicles would dominate oval window actuation. That might not = be true of cartilaginous ossicles in a fluid-filled middle ear space.</div> <div> <div><br> </div> <div> <div>In any event, fetuses have been reported to develop sensitivity to low= frequencies first, followed by high frequencies (Hepper & Shahidullah,= 1994, "The development of fetal hearing"), so the question of wh= at the cochlea picks up is highly dependent on the gestation time point of interest. Gerhardt & Abrams have a r= eview on fetal hearing that you might already have, but I'm attaching just = in case.</div> <div><br> </div> <div>I hope this is helpful. I'd be interested to hear any input you = might get from others.</div> <div><br> </div> <div>Best,</div> <div>Brian</div> <div><br> </div> <div><br> </div> <div><br> </div> <div> <div style=3D"letter-spacing: normal; orphans: auto; text-align: start; tex= t-indent: 0px; text-transform: none; white-space: normal; widows: auto; wor= d-spacing: 0px; word-wrap: break-word;"> <div style=3D"letter-spacing: normal; orphans: auto; text-align: start; tex= t-indent: 0px; text-transform: none; white-space: normal; widows: auto; wor= d-spacing: 0px; word-wrap: break-word;"> <div style=3D"letter-spacing: normal; orphans: auto; text-align: start; tex= t-indent: 0px; text-transform: none; white-space: normal; widows: auto; wor= d-spacing: 0px; word-wrap: break-word;"> <div style=3D"letter-spacing: normal; orphans: auto; text-align: start; tex= t-indent: 0px; text-transform: none; white-space: normal; widows: auto; wor= d-spacing: 0px; word-wrap: break-word;"> <div style=3D"letter-spacing: normal; orphans: auto; text-align: start; tex= t-indent: 0px; text-transform: none; white-space: normal; widows: auto; wor= d-spacing: 0px; word-wrap: break-word;"> <div style=3D"letter-spacing: normal; orphans: auto; text-align: start; tex= t-indent: 0px; text-transform: none; white-space: normal; widows: auto; wor= d-spacing: 0px; word-wrap: break-word;"> <div style=3D"letter-spacing: normal; orphans: auto; text-align: start; tex= t-indent: 0px; text-transform: none; white-space: normal; widows: auto; wor= d-spacing: 0px; word-wrap: break-word;"> <div style=3D"letter-spacing: normal; orphans: auto; text-align: start; tex= t-indent: 0px; text-transform: none; white-space: normal; widows: auto; wor= d-spacing: 0px; word-wrap: break-word;"> <div style=3D"letter-spacing: normal; orphans: auto; text-align: start; tex= t-indent: 0px; text-transform: none; white-space: normal; widows: auto; wor= d-spacing: 0px; word-wrap: break-word;"> <div style=3D"letter-spacing: normal; orphans: auto; text-align: start; tex= t-indent: 0px; text-transform: none; white-space: normal; widows: auto; wor= d-spacing: 0px; word-wrap: break-word;"> <div style=3D"letter-spacing: normal; orphans: auto; text-align: start; tex= t-indent: 0px; text-transform: none; white-space: normal; widows: auto; wor= d-spacing: 0px; word-wrap: break-word;"> <div style=3D"letter-spacing: normal; orphans: auto; text-align: start; tex= t-indent: 0px; text-transform: none; white-space: normal; widows: auto; wor= d-spacing: 0px; word-wrap: break-word;"> <span class=3D"x_Apple-style-span" style=3D"border-collapse:separate; borde= r-spacing:0px"> <div style=3D"word-wrap:break-word"> <div style=3D"margin:0in 0in 0.0001pt"><span style=3D"color:rgb(31,73,125);= background-color:white"><font face=3D"Calibri">Brian B. Monson, PhD</font>= <font face=3D"Calibri, sans-serif"><span style=3D"font-size:14px"></span></= font></span></div> <div style=3D"font-family:Calibri,sans-serif; font-style:normal; margin:0in= 0in 0.0001pt; font-size:11pt"> <br> </div> <div style=3D"font-family:Calibri,sans-serif; font-style:normal; margin:0in= 0in 0.0001pt"> <span style=3D"color:rgb(31,73,125); background-color:white; font-size:12px= ">Research Fellow | </span><span style=3D"font-size:12px; color:rgb(31= ,73,125); background-color:white">Department of Pediatric Newborn Medicine<= /span></div> <div style=3D"font-family:Calibri,sans-serif; font-style:normal; margin:0in= 0in 0.0001pt"> <span style=3D"font-size:12px; color:rgb(31,73,125)">Brigham and Women's Ho= spital <span style=3D"background-color:white">| Harvard Medical School= </span></span></div> <div style=3D"font-family:Calibri,sans-serif; font-style:normal; font-weigh= t:normal; margin:0in 0in 0.0001pt"> <span style=3D"color:rgb(31,73,125); background-color:white; font-size:12px= ">Phone: +617 525 4131 | Email: <span style=3D"color:blue; text-de= coration:underline"><a href=3D"mailto:vsakalidis@xxxxxxxx" style=3D"col= or:blue; text-decoration:underline">bmonson@xxxxxxxx</a></s= pan></span></div> <div style=3D"font-family:Calibri,sans-serif; font-style:normal; font-weigh= t:normal; margin:0in 0in 0.0001pt; font-size:11pt"> <br> </div> </div> </span></div> </div> </div> </div> </div> </div> </div> </div> </div> </div> <br class=3D"x_Apple-interchange-newline"> </div> </div> </div> </div> </div> </div> <div style=3D"word-wrap:break-word"> <div> <div> <div> <div style=3D"letter-spacing: normal; orphans: auto; text-align: start; tex= t-indent: 0px; text-transform: none; white-space: normal; widows: auto; wor= d-spacing: 0px; word-wrap: break-word;"> </div> <br class=3D"x_Apple-interchange-newline"> <br class=3D"x_Apple-interchange-newline"> </div> <br> <div> <div>On Mar 1, 2015, at 2:22 PM, Jan Schnupp <<a href=3D"mailto:jan.schn= upp@xxxxxxxx">jan.schnupp@xxxxxxxx</a>> wrote:</div> <br class=3D"x_Apple-interchange-newline"> <blockquote type=3D"cite"> <div dir=3D"ltr">Dear List, <div><br> </div> <div>I was looking around for literature describing the intra-uterine sound= environment of unborn fetuses and came across this paper</div> <div><a href=3D"http://journals.lww.com/greenjournal/abstract/1992/08000/so= und_levels_in_the_human_uterus.6.aspx">http://journals.lww.com/greenjournal= /abstract/1992/08000/sound_levels_in_the_human_uterus.6.aspx</a><br> </div> <div>which suggests that sound in the uterus - if measured with a hydrophon= e - is essentially unattenuated relative to the source of air born sound an= d shows apparently no low-passing. That would suggest that sound in utero i= s essentially crystal clear and not "muffled" as one might perhaps intuitively suspect. However,= as I was pondering this I wondered: what about the middle ear of unborn ch= ildren? Are they filled with (amniotic?) fluid? Or with air? And does it ma= tter? How good could we expect the cochlea in the unborn to be at picking up sound from the amniotic fluid, and does = that depend on whether the middle ear is fluid or air filled?</div> <div><br> </div> <div>Best wishes,</div> <div><br> </div> <div>Jan</div> <div> <br clear=3D"all"> <div><br> </div> -- <br> <div class=3D"x_gmail_signature">Prof Jan Schnupp<br> University of Oxford<br> Dept. of Physiology, Anatomy and Genetics<br> Sherrington Building - Parks Road<br> Oxford OX1 3PT - UK<br> +44-1865-282012<br> <a href=3D"http://jan.schnupp.net/" target=3D"_blank">http://jan.schnupp.ne= t</a></div> </div> </div> </blockquote> </div> <br> </div> </div> </div> </div> <span><Gerhardt_2000_Fetal Exposures to Sound and Vibroacoustic Stimulat= ion.pdf></span></blockquote> </div> <br> </div> <p></p> <p>The information in this e-mail is intended only for the person to whom i= t is<br> addressed. If you believe this e-mail was sent to you in error and the e-ma= il<br> contains patient information, please contact the Partners Compliance HelpLi= ne at<br> http://www.partners.org/complianceline . If the e-mail was sent to you in e= rror<br> but does not contain patient information, please contact the sender and pro= perly<br> dispose of the e-mail.</p></body> </html> --_000_AC9FEE27F1A2466082EA8E9381EC4C85partnersorg_--