Subject: Re: [AUDITORY] Sensitivity to ITDs with mismatched frequencies in each ear? From: Tanvi Thakkar <tthakkar@xxxxxxxx> Date: Wed, 24 Feb 2021 14:35:14 -0600--0000000000006f7b6105bc1af900 Content-Type: text/plain; charset="UTF-8" Hi Jan, This is a great question. Below are relevant studies from Ruth Litovsky's lab with Alan Kan and Matt Goupell (I am currently a postdoc in her lab). It turns out while mismatch in frequency "worsens" both ITD lateralization and ITD sensitivity in listeners with bilateral cochlear implants, it is quite remarkable how tolerant their lateralization responses and sensitivity are to those frequency mismatches. In my dissertation work I actually explored *temporal mismatches* by imposing binaural beats, using different pulse rates across the ears. I studied how this affects ITD lateralization and auditory object formation. In a nutshell: normally hearing adult listeners typically report hearing two sounds, while bilateral CI listeners are largely unable to dissociate a sound with large temporal mismatches (whereby different stimulation rates were presented across the ears) that have an imposed ITD, reporting the sound as being a single fused source--this isn't something we see with *frequency mismatch* in bilateral CI listeners. I am currently writing up the results but would be happy to share my ARO poster. Best, Tanvi Thakkar *Binaural hearing with electrical stimulation * <https://bhsl.waisman.wisc.edu/wp-content/uploads/sites/114/2017/03/pub_2015KanLitovsky_HearingResearch.pdf> Kan, A., & Litovsky, R. Y. (2015). Binaural hearing with electrical stimulation. Hearing Research, 322, 127-137. *Effect of channel separation and interaural mismatch on fusion and lateralization in normal-hearing and cochlear-implant listeners * <https://bhsl.waisman.wisc.edu/wp-content/uploads/sites/114/2019/08/Kan-et-al_2019_channel-sep-and-Interaural-mismatch_.pdf> Kan, A., Goupell, M., & Litovsky, R. (2019). Effect of channel separation and interaural mismatch on fusion and lateralization in normal-hearing and cochlear implant listeners. J. Acoust. Soc. Am. 146 (2). *Effect of mismatched place-of-stimulation on binaural fusion and lateralization in bilateral cochlear-implant users <https://bhsl.waisman.wisc.edu/wp-content/uploads/sites/114/2017/03/pub_2013Kanetal_JASA.pdf> * Kan, A., Stoelb, C., Litovsky, R. Y., & Goupell, M. J. (2013). Effect of mismatched place-of-stimulation on binaural fusion and lateralization in bilateral cochlear-implant users. The Journal of the Acoustical Society of America, 134(4), 2923-2936. *Effects of interaural pitch matching and auditory image centering on binaural sensitivity in cochlear implant users * <https://bhsl.waisman.wisc.edu/wp-content/uploads/sites/114/2017/03/pub_2015_KanLitovskyGoupell_EarHear.pdf> Kan, A., Litovsky, R.Y., Goupell, M.J. (2015). Effects of interaural pitch matching and auditory image centering on binaural sensitivity in cochlear implant users. Ear and Hearing, 36(3), e62-e68. doi: 10.1097/AUD.0000000000000135 Tanvi Thakkar Postdoctoral Research Fellow, Binaural Hearing and Speech Lab, Waisman Center tanvi.thakkar@xxxxxxxx https://bhsl.waisman.wisc.edu/staff/thakar-tanvi/ <http://www.waisman.wisc.edu/bhl/about_people/People05.html> On Wed, Feb 24, 2021 at 4:47 AM Jan Schnupp < 000000e042a1ec30-dmarc-request@xxxxxxxx> wrote: > Dear List, > > I am curious if you could recommend some reading for me. We have been > increasingly interested in ITD coding with cochlear implants and have > developed a nice little animal model which shows a surprisingly robust > behavioral ITD sensitivity even if deafened in infancy and only implanted > in young adulthood. > One question we often get and which we would like to investigate is: how > much does it matter if there is a bit of a mismatch between the frequency > channels in the left and right ears? How badly do they have to be > mismatched before ITD sensitivity disappears? > I kind of assumed that there must have been a lot of psychoacoustics on > this, at least in normally hearing human subjects. Of course at low > frequencies, if you mismatch the left and right ears you get binaural > beats, but what about envelope ITDs? You could deliver for example trains > of short gabor clicks to each ear with a greater or lesser extent of > carrier frequency mismatch, and see how the mismatch affects ITD > thresholds. It seems like such an obvious thing to try, surely somebody > must have done this or something similar? But a quick look on google > scholar didn't yield very much. A modelling paper by Bonham and Lewis 1999 > was the top hit. I haven't seen much in the way of data. Surely I must be > missing something...? Any suggestions for relevant reading > gratefully accepted. > > Best wishes, > > Jan > > > --------------------------------------- > Prof Jan Schnupp > City University of Hong Kong > Dept. of Neuroscience > 31 To Yuen Street, > Kowloon Tong > Hong Kong > > https://auditoryneuroscience.com > http://jan.schnupp.net > --0000000000006f7b6105bc1af900 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable <div dir=3D"ltr"><p class=3D"MsoNormal" style=3D"margin:0in 0in 0.0001pt;fo= nt-size:11pt;font-family:Calibri,sans-serif">Hi Jan,</p><p class=3D"MsoNorm= al" style=3D"margin:0in 0in 0.0001pt;font-size:11pt;font-family:Calibri,san= s-serif"><br></p><p class=3D"MsoNormal" style=3D"margin:0in 0in 0.0001pt;fo= nt-size:11pt;font-family:Calibri,sans-serif">This is a great question. Below are relevant studies from Ruth Litovsky's la= b with Alan Kan and Matt Goupell (I am currently a postdoc in her lab). It turns o= ut while mismatch in frequency "worsens" both ITD=C2=A0lateralizatio= n and ITD sensitivity in listeners with bilateral cochlear implants, it is qu= ite remarkable how tolerant their lateralization responses and sensitivity are = to those frequency mismatches. In my dissertation work I actually explored <i>= temporal=C2=A0mismatches</i>=C2=A0by imposing binaural beats, using different pulse rates across the ears. I stu= died how this affects=C2=A0ITD lateralization and auditory object formation. In = a nutshell: normally hearing adult listeners typically report hearing two sou= nds, while bilateral CI listeners are largely unable to dissociate a sound with large temporal mismatches (whereby different stimulation rates were presented=C2=A0across the ears)=20 that have an imposed ITD, reporting the sound as being a single fused source--this isn't something we see with=C2=A0<i>frequency=C2=A0mismatch</i>=C2=A0in bilateral CI listeners. I = am currently writing up the results but would be happy to share my ARO poster.= </p><p class=3D"MsoNormal" style=3D"margin:0in 0in 0.0001pt;font-size:11pt;= font-family:Calibri,sans-serif"><br></p><div dir=3D"ltr"><p class=3D"MsoNor= mal" style=3D"margin:0in 0in 0.0001pt;font-size:11pt;font-family:Calibri,sa= ns-serif">Best,</p><p class=3D"MsoNormal" style=3D"margin:0in 0in 0.0001pt;= font-size:11pt;font-family:Calibri,sans-serif">Tanvi Thakkar</p>=C2=A0<br><= span style=3D"font-family:Georgia,serif;color:rgb(73,73,73);font-size:11pt"= >=C2=A0</span><a href=3D"https://bhsl.waisman.wisc.edu/wp-content/uploads/s= ites/114/2017/03/pub_2015KanLitovsky_HearingResearch.pdf" target=3D"_blank"= style=3D"color:blue;font-family:Georgia,serif;font-size:11pt"><b><span sty= le=3D"font-family:Helvetica,sans-serif;color:rgb(4,121,168);border:1pt none= windowtext;padding:0in">Binaural hearing with electrical stimulation=C2=A0= </span></b></a><br><span style=3D"color:rgb(73,73,73);font-family:Georgia,s= erif">Kan, A., & Litovsky, R. Y. (2015). Binaural hearing with electric= al stimulation. Hearing Research, 322, 127-137.</span><br>=C2=A0<a href=3D"= https://bhsl.waisman.wisc.edu/wp-content/uploads/sites/114/2019/08/Kan-et-a= l_2019_channel-sep-and-Interaural-mismatch_.pdf" target=3D"_blank" style=3D= "color:blue;font-size:11pt;font-family:Georgia,serif"><b><span style=3D"fon= t-family:Helvetica,sans-serif;color:rgb(4,121,168);border:1pt none windowte= xt;padding:0in">Effect of channel separation and interaural mismatch on fus= ion and lateralization in normal-hearing and cochlear-implant listeners=C2= =A0</span></b></a><br><span style=3D"color:rgb(73,73,73);font-family:Georgi= a,serif">Kan, A., Goupell, M., & Litovsky, R. (2019). Effect of channel= separation and interaural mismatch on fusion and lateralization in normal-= hearing and cochlear implant listeners. J. Acoust. Soc. Am. 146 (2).</span>= </div><div dir=3D"ltr"><b style=3D"font-family:Georgia,serif;font-size:11pt= ;color:blue"><span style=3D"font-family:Helvetica,sans-serif;color:rgb(4,12= 1,168);border:1pt none windowtext;padding:0in"><a href=3D"https://bhsl.wais= man.wisc.edu/wp-content/uploads/sites/114/2017/03/pub_2013Kanetal_JASA.pdf"= target=3D"_blank" style=3D"color:blue;font-family:Georgia,serif;font-size:= 11pt">Effect of mismatched place-of-stimulation on binaural fusion and late= ralization in bilateral cochlear-implant users=C2=A0</a>=C2=A0</span></b></= div><div dir=3D"ltr"><span style=3D"color:rgb(73,73,73);font-family:Georgia= ,serif">Kan, A., Stoelb, C., Litovsky, R. Y., & Goupell, M. J. (2013). = Effect of mismatched place-of-stimulation on binaural fusion and lateraliza= tion in bilateral cochlear-implant users. The Journal of the Acoustical Soc= iety of America, 134(4), 2923-2936.</span></div><div dir=3D"ltr"><a href=3D= "https://bhsl.waisman.wisc.edu/wp-content/uploads/sites/114/2017/03/pub_201= 5_KanLitovskyGoupell_EarHear.pdf" target=3D"_blank" style=3D"color:blue;fon= t-family:Georgia,serif;font-size:11pt"><b><span style=3D"font-family:Helvet= ica,sans-serif;color:rgb(4,121,168);border:1pt none windowtext;padding:0in"= >Effects of interaural pitch matching and auditory image centering on binau= ral sensitivity in cochlear implant users=C2=A0</span></b></a><br><span sty= le=3D"color:rgb(73,73,73);font-family:Georgia,serif">Kan, A., Litovsky, R.Y= ., Goupell, M.J. (2015). Effects of interaural pitch matching and auditory = image centering on binaural sensitivity in cochlear implant users. Ear and = Hearing, 36(3), e62-e68. doi: 10.1097/AUD.0000000000000135</span></div><div= dir=3D"ltr"><span style=3D"color:rgb(73,73,73);font-family:Georgia,serif">= <br></span></div><p class=3D"MsoNormal" style=3D"margin:0in 0in 0.0001pt;fo= nt-size:11pt;font-family:Calibri,sans-serif"><br></p><div><div dir=3D"ltr" = class=3D"gmail_signature" data-smartmail=3D"gmail_signature"><div dir=3D"lt= r"><div><div dir=3D"ltr">Tanvi Thakkar<div>Postdoctoral Research Fellow, Bi= naural Hearing and Speech Lab, Waisman Center</div><div><a href=3D"mailto:t= anvi.thakkar@xxxxxxxx" target=3D"_blank">tanvi.thakkar@xxxxxxxx</a></div><d= iv><a href=3D"http://www.waisman.wisc.edu/bhl/about_people/People05.html" t= arget=3D"_blank">https://bhsl.waisman.wisc.edu/staff/thakar-tanvi/</a></div= ></div></div></div></div></div><br></div><br><div class=3D"gmail_quote"><di= v dir=3D"ltr" class=3D"gmail_attr">On Wed, Feb 24, 2021 at 4:47 AM Jan Schn= upp <<a href=3D"mailto:000000e042a1ec30-dmarc-request@xxxxxxxx">0= 00000e042a1ec30-dmarc-request@xxxxxxxx</a>> wrote:<br></div><bloc= kquote class=3D"gmail_quote" style=3D"margin:0px 0px 0px 0.8ex;border-left:= 1px solid rgb(204,204,204);padding-left:1ex"><div dir=3D"ltr">Dear List,<di= v><br></div><div>I am curious if you could recommend some reading for me. W= e have been increasingly interested in ITD coding with cochlear implants an= d have developed a nice little animal model which shows a surprisingly robu= st behavioral ITD sensitivity even if deafened in infancy and only implante= d in young adulthood.=C2=A0</div><div>One question we often get and which w= e would like to investigate is: how much does it matter if there is a bit o= f a mismatch between the frequency channels in the left and right ears? How= badly do they have to be mismatched before ITD sensitivity disappears?</di= v><div>I kind of assumed that there must have been a lot of psychoacoustics= on this, at least in normally hearing human subjects. Of course at low fre= quencies, if you mismatch the left and right ears you get binaural beats, b= ut what about envelope ITDs?=C2=A0You could deliver for example trains of s= hort gabor clicks to each ear with a greater or lesser extent of carrier fr= equency mismatch, and see how the=C2=A0mismatch affects ITD thresholds. It = seems like such an obvious thing to try, surely somebody must have done thi= s or something similar? But a quick look on google scholar didn't yield= very much. A modelling paper by Bonham and Lewis 1999 was the top hit. I h= aven't seen much in the way of data. Surely I must be missing something= ...? Any suggestions for relevant reading gratefully=C2=A0accepted.=C2=A0</= div><div><br></div><div>Best wishes,</div><div><br></div><div>Jan</div><div= ><br clear=3D"all"><div><div dir=3D"ltr"><div dir=3D"ltr"><div><div dir=3D"= ltr"><div><div dir=3D"ltr"><div dir=3D"ltr"><div dir=3D"ltr"><div dir=3D"lt= r"><div style=3D"font-size:12.8px"><br></div><div style=3D"font-size:12.8px= ">---------------------------------------</div><div style=3D"font-size:12.8= px">Prof Jan Schnupp<br>City University of Hong Kong<br>Dept. of Neuroscien= ce</div><div><div style=3D"font-size:12.8px">31 To Yuen Street,=C2=A0</div>= <div style=3D"font-size:12.8px"><span style=3D"font-size:12.8px">Kowloon To= ng</span></div><div style=3D"font-size:12.8px">Hong Kong</div><div style=3D= "font-size:12.8px"><br></div><a href=3D"https://auditoryneuroscience.com" t= arget=3D"_blank">https://auditoryneuroscience.com</a></div><div><a href=3D"= http://jan.schnupp.net" target=3D"_blank">http://jan.schnupp.net</a></div><= /div></div></div></div></div></div></div></div></div></div></div></div> </blockquote></div> --0000000000006f7b6105bc1af900--