Re: [AUDITORY] Cochlear Implants - To interleave or not to interleave? (Bernhard Laback )

Subject: Re: [AUDITORY] Cochlear Implants - To interleave or not to interleave? From: Bernhard Laback <bernhard.laback@xxxxxxxx> Date: Wed, 28 Sep 2022 11:42:43 +0200 This is a multi-part message in MIME format. --------------UiivHguCGboMJ2f7G9LrsfK0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: quoted-printable X-MIME-Autoconverted: from 8bit to quoted-printable by edgeum3.it.mcgill.ca id 28S9goVm097188 Dear Jan, I completely agree with you that it is worth to think more about=20 reconsidering the strict interpretation of the CIS concept (which is=20 principally very useful and has been very successful). Particularly, I think that it would make sense to consider coding=20 schemes in which the decision on permitting simultaneous stimulation is=20 based on the spectro-temporal signal properties. Thus, at points in time=20 where high spectral resolution is not so important, permitting=20 simultaneous stimulation might be helpful in providing more flexibility=20 for conveying timing information (most importantly interaural time=20 difference). Of course, defining criteria for this decision is not=20 straight-forward and would likely require extensive research. The=20 demands might also differ between single- and multi-source stimuli. An idea about effects of simultaneous stimulation and means how to=20 reduce their effects can be found in Bader et al. (2013, see=20 https://pubmed.ncbi.nlm.nih.gov/23742364/). Best regards, Bernhard Am 28-Sep-22 um 10:24 AM schrieb Jan Schnupp: > Dear List, > > it is my understanding that the vast majority of CI sound processors=20 > in use today are still based or inspired more or less=C2=A0on some vari= ant=20 > of the Continuous Interleaved Sampling algorithm, and that one of the=20 > key assumptions / design features of the algorithms in use is that=20 > having more than one electrode channel active in any one ear at the=20 > same time is to be avoided. Hence "interleaved" sampling: channels=20 > take turns to ensure they aren't active at once. What I am curious to=20 > know is: quite how bad would it be if this assumption was violated? Is=20 > it necessarily=C2=A0always very bad? And how certain can we be about ho= w=20 > bad it is? Have=C2=A0people run head-to-head comparisons of strategies = with=20 > and without strict interleaving? > Intuitively, while I see that having multiple channels active at once=20 > may exacerbate problems with the already relatively poor channel=20 > isolation, I also think that forcing channels to fire "in turn"=20 > constrains the timing of pulses in a manner that may preclude=20 > independent temporal coding on different channels. Has this potential=20 > trade-off been considered? Is there a well founded consensus that the=20 > downsides of having the potential of temporal collisions of pulses in=20 > different channels will necessarily outweigh potential upsides from=20 > having richer temporal patterning across channels? > > I would be grateful for references / papers / views / perspectives=20 > relevant to this topic. > > Many thanks! > > 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 --=20 Doz. Dr. Bernhard Laback Hearing Cluster, Head Psychacoustics and Experimental Audiology Group, Head Acoustics Research Institute Austrian Academy of Sciences Wohllebengasse 12-14, 1040 Wien, Austria Tel.: +43 1 51581-2514 www.oeaw.ac.at/isf --------------UiivHguCGboMJ2f7G9LrsfK0 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-MIME-Autoconverted: from 8bit to quoted-printable by edgeum3.it.mcgill.ca id 28S9goVm097188 <html> <head> <meta http-equiv=3D"Content-Type" content=3D"text/html; charset=3DUTF= -8"> </head> <body> <p> </p>  <p class=3D"MsoNormal">Dear Jan, </p> <p class=3D"MsoNormal">I completely agree with you that it is worth t= o think more about reconsidering the strict interpretation of the CIS concept (which is principally very useful and has been very successful). </p> <p class=3D"MsoNormal">Particularly, I think that it would make sense to consider coding schemes in which the decision on permitting simultaneous stimulation is based on the spectro-temporal signal properties. Thus, at points in time where high spectral resolution is not so important, permitting simultaneous stimulation might be helpful in providing more flexibility for conveying timing information (most importantly interaural time difference). Of course, defining criteria for this decision is not straight-forward and would likely require extensive research. The demands might also differ between single- and multi-source stimuli. </p> <p class=3D"MsoNormal">An idea about effects of simultaneous stimulation and means how to reduce their effects can be found in Bader et al. (2013, see <a href=3D"https://pubmed.ncbi.nlm.nih.gov/23742364/" class=3D"moz-txt-link-freetext">https://pubmed.ncbi.nlm.nih.gov/2= 3742364/</a>). <br> </p> <p class=3D"MsoNormal">Best regards, <br> Bernhard<br> </p> <span style=3D"font-size:11.0pt;line-height:107%;font-family:"Calibri&quot= ;,sans-serif;mso-ascii-theme-font:minor-latin;mso-fareast-font-family:Cal= ibri;mso-fareast-theme-font: minor-latin;mso-hansi-theme-font:minor-latin;mso-bidi-font-family:"T= imes New Roman"; mso-bidi-theme-font:minor-bidi;mso-ansi-language:EN-US;mso-fareast-langua= ge: EN-US;mso-bidi-language:AR-SA"></span> <p></p> <div class=3D"moz-cite-prefix">Am 28-Sep-22 um 10:24 AM schrieb Jan Schnupp:<br> </div> <blockquote type=3D"cite" cite=3D"mid:CAJptJs7-eibgbch0YhBjL0MAffX-rxbK-JkoAQKuzWeFYmwfrQ@xxxxxxxx= l.com"> <meta http-equiv=3D"Content-Type" content=3D"text/html; charset=3DU= TF-8"> <div dir=3D"ltr">Dear List, <div><br> </div> <div>it is my understanding that the vast majority of CI sound processors in use today are still based or inspired more or less=C2=A0on some variant of the Continuous Interleaved Samplin= g algorithm, and that one of the key assumptions / design features of the algorithms in use is that having more than one electrode channel active in any one ear at the same time is to be avoided. Hence "interleaved" sampling: channels take turns to ensure they aren't active at once. What I am curious to know is: quite how bad would it be if this assumption was violated? Is it necessarily=C2=A0always very bad? And how certa= in can we be about how bad it is? Have=C2=A0people run head-to-hea= d comparisons of strategies with and without strict interleaving?=C2=A0</div> <div>Intuitively, while I see that having multiple channels active at once may exacerbate problems with the already relatively poor channel isolation, I also think that forcing channels to fire "in turn" constrains the timing of pulses in a manner that may preclude independent temporal coding on different channels. Has this potential trade-off been considered? Is there a well founded consensus that the downsides of having the potential of temporal collisions of pulses in different channels will necessarily outweigh potential upsides from having richer temporal patterning across channels?=C2=A0</div> <div><br> </div> <div>I would be grateful for references / papers / views / perspectives relevant to this topic.</div> <div><br> </div> <div>Many thanks!</div> <div><br> </div> <div>Jan</div> <div> <div> <div dir=3D"ltr" class=3D"gmail_signature" data-smartmail=3D"gmail_signature"> <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"ltr"> <div style=3D"font-size:12.8px"><br> </div> <div style=3D"font-size:12.8px">-----------= ----------------------------</div> <div style=3D"font-size:12.8px">Prof Jan Schnupp<br> City University of Hong Kong<br> Dept. of Neuroscience</div> <div> <div style=3D"font-size:12.8px">31 To Yue= n Street,=C2=A0</div> <div style=3D"font-size:12.8px"><span style=3D"font-size:12.8px">Kowloon Tong</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.co= m" target=3D"_blank" moz-do-not-send=3D"tr= ue" class=3D"moz-txt-link-freetext">https:/= /auditoryneuroscience.com</a></div> <div><a href=3D"http://jan.schnupp.net" target=3D"_blank" moz-do-not-send=3D"tr= ue" class=3D"moz-txt-link-freetext">http://= jan.schnupp.net</a></div> </div> </div> </div> </div> </div> </div> </div> </div> </div> </div> </div> </div> </blockquote> <pre class=3D"moz-signature" cols=3D"72">--=20 Doz. Dr. Bernhard Laback Hearing Cluster, Head Psychacoustics and Experimental Audiology Group, Head Acoustics Research Institute=20 Austrian Academy of Sciences Wohllebengasse 12-14, 1040 Wien, Austria Tel.: +43 1 51581-2514 <a class=3D"moz-txt-link-abbreviated" href=3D"http://www.oeaw.ac.at/isf">= www.oeaw.ac.at/isf</a></pre> </body> </html> --------------UiivHguCGboMJ2f7G9LrsfK0--

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