Precompensating for spread of excitation in a cochlear implant coding strategy

Cochlear Implant Research and Development in the Twenty-first Century: A Critical Update

“…This is one reason why, when evaluating published studies, we have stressed the importance of basic aspects of experimental design such as blinding and the inclusion of adequate control groups or conditions; even small biases or experimenter effects may be of a similar size to the genuine advances one is trying to measure. Fortunately, attention to these basic tenets is now becoming the norm, for example with many recent studies incorporating a double-blind design (Magnusson 2011a; Koning and Wouters 2016;Nogueira et al 2016;Riss et al 2016;Bolner et al 2020;Lopez-Poveda et al 2020). Future improvements may build on the increased use in other areas of science and medicine of pre-registered reports (Munafò et al 2017)-something that would be particularly useful in studies where there are multiple dependent variables and/or possible data analyses.…”

“…Nogueira et al (2016) introduced the Spectral Enhancement Strategy (SES), which attenuates energy in the spectral valleys prior to channel selection, and reported a 0.57 dB improvement in SRT relative to ACE. Bolner et al (2020) described another method, termed SPACE, that compensates for the estimated current spread from each electrode prior to the channel selection stage. When applied to mixtures of target speech in four-talker babble, without prior knowledge of the clean speech, it produced a significant 1.4 dB reduction in SRT averaged across six participants, compared to the standard ACE strategy.…”

Cochlear implant research and development in the 21st century: A critical update

“…This is one reason why, when evaluating published studies, we have stressed the importance of basic aspects of experimental design such as blinding and the inclusion of adequate control groups or conditions; even small biases or experimenter effects may be of a similar size to the genuine advances one is trying to measure. Fortunately, attention to these basic tenets is now becoming the norm, for example with many recent Carlyon & Goehring -21 st century CI 41 studies incorporating a double-blind design (Magnusson, 2011a;Koning and Wouters, 2016;Nogueira et al, 2016;Riss et al, 2016;Bolner et al, 2020;Lopez-Poveda et al, 2020).…”

“…Finally, it will be important to determine whether the advances obtained by different approaches are additive -an issue that led one scientist to remark, only half-jokingly, that they had Carlyon & Goehring -21 st century CI 42 seen so many 5% improvements reported throughout their career that patients should now be scoring more that 100% on speech tests. For example, the various processing algorithms that enhance modulations across time (Koning and Wouters, 2016;Lamping et al, 2020) or across electrodes (Nogueira et al, 2016;Bolner et al, 2020;Lopez-Poveda et al, 2020) are likely addressing the same basic goal of increasing the contrast in the pattern of electrical stimulation (electrodogram), typically by attenuating or removing loweramplitude pulses. To the extent that different algorithms attenuate the same pulses their benefits may not sum.…”

“…Similarly, although the criteria used for different channel deselection algorithms may reflect different aspects of neural health (Pfingst et al, 2015;Brochier et al, 2021a), the need to retain some minimum number of channels of information for speech perception may make it impractical to combine them. In contrast, it might be possible to combine the advantages of temporal or spectral enhancement algorithms with either channel de-activation methods or with algorithms that enhance the representation of F0 in the electrodogram (Nogueira et al, 2016;Lopez-Poveda et al, 2017;Bolner et al, 2020;Lopez-Poveda et al, 2020). Furthermore, it may well be that pre-processing algorithms that increase the SNR at the input stage of the CI contribute somewhat independently to the improvements introduced by changes to the algorithm or by channel de-activation methods.…”