Adding simultaneous stimulating channels to reduce power consumption in cochlear implants

&NA; Sound coding strategies for Cochlear Implant (CI) listeners can be used to control the trade‐off between speech performance and power consumption. Most commercial CI strategies use non‐simultaneous channel stimulation, stimulating only one electrode at a time. One could add parallel simultaneous stimulating channels such that the electrical interaction between channels is increased. This would produce spectral smearing, because the electrical fields of the simultaneous stimulated channels interact, but also power savings. The parallel channels produce a louder sensation than sequential stimulation. To test this hypothesis we implemented different sound coding strategies using a research interface from Advanced Bionics: the commercial F120 strategy using sequential channel stimulation (one channel equals two electrodes with current steering) and the Paired strategy, consisting of simultaneous stimulation with two channels. Here, the electrical field of both channels will interact, requiring less current on each channel to perceive the same loudness as with F120. However, channel interaction between the independent channels may reduce speech recognition or understanding. This can be diminished by adding an inverse‐polarity stimulation channel between both channels. This strategy is termed Paired with Flanks. Additionally, Triplet with three channels and an adjacent Flank style was investigated. For each strategy we measured speech intelligibility with the Hochmair‐Schulz‐Moser sentence test. Spectral resolution was assessed using a spectral modulation depth detection task. Results show that Paired without Flanks obtains similar performance while reducing the current by 20% on average compared to F120. Triplet with and without Flanks shows overall poorer performance when compared to F120. All strategies inhibit the option to increase the pulse width which would result in even further decreased power consumption. HighlightsNew cochlear implant stimulation mode for reduced electrical interaction proposed.Simultaneous stimulation with additional inversely phased electrodes (Flanks).Flanks can reduce electrical interaction to some degree.Polarity effects need to be considered when stimulating simultaneously with both polarities.Paired strategy shows best trade‐off between performance and power consumption.

[1]  Jong Ho Won,et al.  Spectral-Ripple Resolution Correlates with Speech Reception in Noise in Cochlear Implant Users , 2007, Journal of the Association for Research in Otolaryngology.

[2]  M. Demorest,et al.  Use of Test‐Retest Measures to Evaluate Performance Stability in Adults with Cochlear Implants , 1995, Ear and hearing.

[3]  Andrew J Oxenham,et al.  Assessing the role of spectral and intensity cues in spectral ripple detection and discrimination in cochlear-implant users. , 2012, The Journal of the Acoustical Society of America.

[4]  Philipos C. Loizou,et al.  Effects of electrode design and configuration on channel interactions , 2006, Hearing Research.

[5]  B. Pfingst,et al.  Stimulus features affecting psychophysical detection thresholds for electrical stimulation of the cochlea. I: Phase duration and stimulus duration. , 1991, The Journal of the Acoustical Society of America.

[6]  Gail S Donaldson,et al.  Place-pitch discrimination of single- versus dual-electrode stimuli by cochlear implant users (L). , 2005, The Journal of the Acoustical Society of America.

[7]  Philipos C Loizou,et al.  Comparison of Speech Processing Strategies Used in the Clarion Implant Processor , 2003, Ear and hearing.

[8]  Hui-Mei Yang,et al.  Tone Discrimination and Speech Perception Benefit in Mandarin-Speaking Children Fit With HiRes Fidelity 120 Sound Processing , 2009, Otology & neurotology : official publication of the American Otological Society, American Neurotology Society [and] European Academy of Otology and Neurotology.

[9]  Matthijs Killian,et al.  Clinical evaluation of cochlear implant sound coding taking into account conjectural masking functions, MP3000™ , 2011, Cochlear implants international.

[10]  D. W. Smith,et al.  Effects of electrode configuration on psychophysical strength-duration functions for single biphasic electrical stimuli in cats. , 1997, The Journal of the Acoustical Society of America.

[11]  Thomas Lenarz,et al.  A Psychoacoustic "NofM"-Type Speech Coding Strategy for Cochlear Implants , 2005, EURASIP J. Adv. Signal Process..

[12]  Andreas Büchner,et al.  Loudness and pitch perception using Dynamically Compensated Virtual Channels , 2017, Hearing Research.

[13]  Bertrand Delgutte,et al.  Improved neural representation of vowels in electric stimulation using desynchronizing pulse trains. , 2003, The Journal of the Acoustical Society of America.

[14]  E. Javel,et al.  Electrical stimulation of the auditory nerve: II. Effect of stimulus waveshape on single fibre response properties , 1999, Hearing Research.

[15]  A. Büchner,et al.  Spectral contrast enhancement improves speech intelligibility in noise for cochlear implants. , 2016, The Journal of the Acoustical Society of America.

[16]  Johan H. M. Frijns,et al.  Threshold Levels of Dual Electrode Stimulation in Cochlear Implants , 2013, Journal of the Association for Research in Otolaryngology.

[17]  Fa-Long Luo,et al.  Spectral contrast enhancement: Algorithms and comparisons , 2003, Speech Commun..

[18]  Lucas H M Mens,et al.  Current Steering and Current Focusing in Cochlear Implants: Comparison of Monopolar, Tripolar, and Virtual Channel Electrode Configurations , 2008, Ear and hearing.

[19]  Comparison of a Paired or Sequential Stimulation Paradigm with Advanced Bionics' High-Resolution Mode , 2005, Otology & neurotology : official publication of the American Otological Society, American Neurotology Society [and] European Academy of Otology and Neurotology.

[20]  Belinda A Henry,et al.  Spectral peak resolution and speech recognition in quiet: normal hearing, hearing impaired, and cochlear implant listeners. , 2005, The Journal of the Acoustical Society of America.

[21]  Thomas Lenarz,et al.  Evaluation of the Harmony Soundprocessor in Combination With the Speech Coding Strategy HiRes 120 , 2008, Otology & neurotology : official publication of the American Otological Society, American Neurotology Society [and] European Academy of Otology and Neurotology.

[22]  R. K. Kalkman,et al.  Simultaneous and non-simultaneous dual electrode stimulation in cochlear implants: evidence for two neural response modalities , 2009, Acta oto-laryngologica.

[23]  Robert V. Shannon,et al.  Multichannel electrical stimulation of the auditory nerve in man. II. Channel interaction , 1983, Hearing Research.

[24]  K. Plant,et al.  Speech Perception as a Function of Electrical Stimulation Rate: Using the Nucleus 24 Cochlear Implant System , 2000, Ear and hearing.

[25]  R. Carlyon,et al.  Polarity effects on place pitch and loudness for three cochlear-implant designs and at different cochlear sites. , 2013, The Journal of the Acoustical Society of America.

[26]  Fan-Gang Zeng,et al.  Cochlear Implants: System Design, Integration, and Evaluation , 2008, IEEE Reviews in Biomedical Engineering.

[27]  Anthony J Spahr,et al.  Spectral modulation detection and vowel and consonant identifications in cochlear implant listeners. , 2009, The Journal of the Acoustical Society of America.

[28]  Blake S. Wilson,et al.  Cochlear implants: A remarkable past and a brilliant future , 2008, Hearing Research.

[29]  Mark Downing,et al.  Current Steering Creates Additional Pitch Percepts in Adult Cochlear Implant Recipients , 2007, Otology & neurotology : official publication of the American Otological Society, American Neurotology Society [and] European Academy of Otology and Neurotology.

[30]  I. Hochmair-Desoyer,et al.  The HSM sentence test as a tool for evaluating the speech understanding in noise of cochlear implant users. , 1997, The American journal of otology.

[31]  Belinda A Henry,et al.  The resolution of complex spectral patterns by cochlear implant and normal-hearing listeners. , 2003, The Journal of the Acoustical Society of America.

[32]  Th Lenarz,et al.  Investigation of stimulation rates between 500 and 5000 pps with the Clarion 1.2, Nucleus CI24 and Clarion CII devices , 2005, Cochlear implants international.

[33]  David M. Landsberger,et al.  Virtual channel discrimination is improved by current focusing in cochlear implant recipients , 2009, Hearing Research.

[34]  Mark Downing,et al.  Using Current Steering to Increase Spectral Resolution in CII and HiRes 90K Users , 2007, Ear and hearing.

[35]  Jörn Ostermann,et al.  Signal Processing Strategies for Cochlear Implants Using Current Steering , 2011, EURASIP J. Adv. Signal Process..

[36]  Bertrand Delgutte,et al.  Desynchronization of electrically evoked auditory-nerve activity by high-frequency pulse trains of long duration. , 2003, The Journal of the Acoustical Society of America.

[37]  Jong Ho Won,et al.  Sensitivity of psychophysical measures to signal processor modifications in cochlear implant users , 2010, Hearing Research.

[38]  F B Simmons,et al.  Electrical stimulation of the auditory nerve in man. , 1966, Archives of otolaryngology.

[39]  David M Landsberger,et al.  The development of a modified spectral ripple test. , 2013, The Journal of the Acoustical Society of America.

[40]  R. Shannon,et al.  Effects of phase duration and electrode separation on loudness growth in cochlear implant listeners. , 2000, The Journal of the Acoustical Society of America.

[41]  Julie Arenberg Bierer,et al.  Threshold and channel interaction in cochlear implant users: evaluation of the tripolar electrode configuration. , 2007, The Journal of the Acoustical Society of America.

[42]  Mahan Azadpour,et al.  A Psychophysical Method for Measuring Spatial Resolution in Cochlear Implants , 2012, Journal of the Association for Research in Otolaryngology.

[43]  Anthony J Spahr,et al.  Loudness growth observed under partially tripolar stimulation: model and data from cochlear implant listeners. , 2007, The Journal of the Acoustical Society of America.

[44]  M. Dorman,et al.  The effect of parametric variations of cochlear implant processors on speech understanding. , 2000, The Journal of the Acoustical Society of America.

[45]  Robert S Hong,et al.  Signal Coding in Cochlear Implants: Exploiting Stochastic Effects of Electrical Stimulation , 2003, The Annals of otology, rhinology & laryngology. Supplement.

[46]  Fan-Gang Zeng,et al.  Cochlear-implant spatial selectivity with monopolar, bipolar and tripolar stimulation , 2012, Hearing Research.

[47]  G M Clark,et al.  The Contour Electrode Array: Safety Study and Initial Patient Trials of a New Perimodiolar Design , 2001, Otology & neurotology : official publication of the American Otological Society, American Neurotology Society [and] European Academy of Otology and Neurotology.

[48]  William M. Rabinowitz,et al.  Better speech recognition with cochlear implants , 1991, Nature.

[49]  Robert S. C. Cowan,et al.  Initial Clinical Experience With a Totally Implantable Cochlear Implant Research Device , 2008, Otology & neurotology : official publication of the American Otological Society, American Neurotology Society [and] European Academy of Otology and Neurotology.

[50]  Jeroen J Briaire,et al.  Effects of Pulse Width, Pulse Rate and Paired Electrode Stimulation on Psychophysical Measures of Dynamic Range and Speech Recognition in Cochlear Implants , 2012, Ear and hearing.

[51]  Anthony J Spahr,et al.  Relationship between perception of spectral ripple and speech recognition in cochlear implant and vocoder listeners. , 2007, The Journal of the Acoustical Society of America.