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J Am Acad Audiol 2017; 28(09): 786-798
DOI: 10.3766/jaaa.16144
Articles
Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Effect of Stimulus Polarity on Physiological Spread of Excitation in Cochlear Implants

Emily R. Spitzer
*   Boys Town National Research Hospital, Omaha, NE
†   University of North Carolina-Chapel Hill, Chapel Hill, NC
,
Michelle L. Hughes
*   Boys Town National Research Hospital, Omaha, NE
› Author Affiliations
Further Information

Publication History

Publication Date:
26 June 2020 (online)

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Abstract

Background:

Contemporary cochlear implants (CIs) use cathodic-leading, symmetrical, biphasic current pulses, despite a growing body of evidence that suggests anodic-leading pulses may be more effective at stimulating the auditory system. However, since much of this research on humans has used pseudomonophasic pulses or biphasic pulses with unusually long interphase gaps, the effects of stimulus polarity are unclear for clinically relevant (i.e., symmetric biphasic) stimuli.

Purpose:

The purpose of this study was to examine the effects of stimulus polarity on basic characteristics of physiological spread-of-excitation (SOE) measures obtained with the electrically evoked compound action potential (ECAP) in CI recipients using clinically relevant stimuli.

Research Design:

Using a within-subjects (repeated measures) design, we examined the differences in mean amplitude, peak electrode location, area under the curve, and spatial separation between SOE curves obtained with anodic- and cathodic-leading symmetrical, biphasic pulses.

Study Sample:

Fifteen CI recipients (ages 13–77) participated in this study. All were users of Cochlear Ltd. devices.

Data Collection and Analysis:

SOE functions were obtained using the standard forward-masking artifact reduction method. Probe electrodes were 5–18, and they were stimulated at an 8 (of 10) loudness rating (“loud”). Outcome measures (mean amplitude, peak electrode location, curve area, and spatial separation) for each polarity were compared within subjects.

Results:

Anodic-leading current pulses produced ECAPs with larger average amplitudes, greater curve area, and less spatial separation between SOE patterns compared with that for cathodic-leading pulses. There was no effect of polarity on peak electrode location.

Conclusions:

These results indicate that for equal current levels, the anodic-leading polarity produces broader excitation patterns compared with cathodic-leading pulses, which reduces the spatial separation between functions. This result is likely due to preferential stimulation of the central axon. Further research is needed to determine whether SOE patterns obtained with anodic-leading pulses better predict pitch discrimination.

Key Words

cochlear implant - electrically evoked compound action potential - spread of excitation - stimulus polarity

This research was supported by grants R01 DC009595, P30 DC04662, and T35 DC008757 from the NIH and NIDCD.


Data from this study was presented at the 2017 American Auditory Society Scientific and Technology Meeting, Scottsdale, AZ, March 2–4, 2017.


The content of this project is solely the responsibility of the authors and does not necessarily represent the official views of the NIDCD or the NIH.


 

  • REFERENCES

  • Abbas PJ, Brown CJ, Shallop JK, Firszt JB, Hughes ML, Hong SH, Staller SJ. 1999; Summary of results using the nucleus CI24M implant to record the electrically evoked compound action potential. Ear Hear 20 (01) 45-59
    CrossrefPubMedGoogle Scholar
  • Abbas PJ, Hughes ML, Brown CJ, Miller CA, South H. 2004; Channel interaction in cochlear implant users evaluated using the electrically evoked compound action potential. Audiol Neurootol 9 (04) 203-213
    CrossrefPubMedGoogle Scholar
  • Biesheuvel JD, Briaire JJ, Frijns JH. 2016; A novel algorithm to derive spread of excitation based on deconvolution. Ear Hear 37 (05) 572-581
    PubMedGoogle Scholar
  • Carlyon RP, Deeks JM, Macherey O. 2013; Polarity effects on place pitch and loudness for three cochlear-implant designs and at different cochlear sites. J Acoust Soc Am 134 (01) 503-509
    CrossrefPubMedGoogle Scholar
  • Chatterjee M, Galvin 3rd JJ, Fu Q-J, Shannon RV. 2006; Effects of stimulation mode, level and location on forward-masked excitation patterns in cochlear implant patients. J Assoc Res Otolaryngol 7 (01) 15-25
    CrossrefPubMedGoogle Scholar
  • Cohen LT, Richardson LM, Saunders E, Cowan RSC. 2003; Spatial spread of neural excitation in cochlear implant recipients: comparison of improved ECAP method and psychophysical forward masking. Hear Res 179 1–2 72-87
    CrossrefPubMedGoogle Scholar
  • Cosentino S, Gaudrain E, Deeks JM, Carlyon RP. 2016; Multistage nonlinear optimization to recover neural activation patterns from evoked compound action potentials of cochlear implant users. IEEE Trans Biomed Eng 63 (04) 833-840
    PubMedGoogle Scholar
  • Goehring JL, Neff DL, Baudhuin JL, Hughes ML. 2014; a Pitch ranking, electrode discrimination, and physiological spread-of-excitation using Cochlear’s dual-electrode mode. J Acoust Soc Am 136 (02) 715-727
    CrossrefPubMedGoogle Scholar
  • Goehring JL, Neff DL, Baudhuin JL, Hughes ML. 2014; b Pitch ranking, electrode discrimination, and physiological spread of excitation using current steering in cochlear implants. J Acoust Soc Am 136 (06) 3159-3171
    CrossrefPubMedGoogle Scholar
  • Hinojosa R, Marion M. 1983; Histopathology of profound sensorineural deafness. Ann N Y Acad Sci 405: 459-484
    CrossrefPubMedGoogle Scholar
  • Hughes ML. 2008; A re-evaluation of the relation between physiological channel interaction and electrode pitch ranking in cochlear implants. J Acoust Soc Am 124 (05) 2711-2714
    CrossrefPubMedGoogle Scholar
  • Hughes ML, Abbas PJ. 2006; The relation between electrophysiologic channel interaction and electrode pitch ranking in cochlear implant recipients. J Acoust Soc Am 119 (03) 1527-1537
    CrossrefPubMedGoogle Scholar
  • Hughes ML, Goehring JL, Baudhuin JL. 2017 Effects of stimulus polarity and artifact reduction method on the electrically evoked compound action potential. Ear Hear. [epub ahead of print 30 December 2016] doi: 10.1097/AUD.0000000000000392
    CrossrefPubMedGoogle Scholar
  • Hughes ML, Stille LJ. 2008; Psychophysical versus physiological spatial forward masking and the relation to speech perception in cochlear implants. Ear Hear 29 (03) 435-452
    CrossrefPubMedGoogle Scholar
  • Hughes ML, Stille LJ. 2010; Effect of stimulus and recording parameters on spatial spread of excitation and masking patterns obtained with the electrically evoked compound action potential in cochlear implants. Ear Hear 31 (05) 679-692
    CrossrefPubMedGoogle Scholar
  • Hughes ML, Stille LJ, Baudhuin JL, Goehring JL. 2013; ECAP spread of excitation with virtual channels and physical electrodes. Hear Res 306: 93-103
    CrossrefPubMedGoogle Scholar
  • Kawano A, Seldon HL, Clark GM, Ramsden RT, Raine CH. 1998; Intracochlear factors contributing to psychophysical percepts following cochlear implantation. Acta Otolaryngol 118 (03) 313-326
    CrossrefPubMedGoogle Scholar
  • Khan AM, Whiten DM, Nadol Jr JB, Eddington DK. 2005; Histopathology of human cochlear implants: correlation of psychophysical and anatomical measures. Hear Res 205 1–2 83-93
    CrossrefPubMedGoogle Scholar
  • Klop WMC, Hartlooper A, Briare JJ, Frijns JHM. 2004; A new method for dealing with the stimulus artefact in electrically evoked compound action potential measurements. Acta Otolaryngol 124 (02) 137-143
    CrossrefPubMedGoogle Scholar
  • Kwon BJ, van den Honert C. 2006; Effect of electrode configuration on psychophysical forward masking in cochlear implant listeners. J Acoust Soc Am 119 (5 Pt 1) 2994-3002
    CrossrefPubMedGoogle Scholar
  • Macherey O, Carlyon RP, van Wieringen A, Deeks JM, Wouters J. 2008; Higher sensitivity of human auditory nerve fibers to positive electrical currents. J Assoc Res Otolaryngol 9 (02) 241-251
    CrossrefPubMedGoogle Scholar
  • Macherey O, van Wieringen A, Carlyon P, Deeks J, Wouters J. 2006; Asymmetric pulses in cochlear implants: effects of pulse shape, polarity, and rate. J Assoc Res Otolaryngol 7 (03) 253-266
    CrossrefPubMedGoogle Scholar
  • Macherey O, van Wieringen A, Carlyon RP, Dhooge I, Wouters J. 2010; Forward-masking patterns produced by symmetric and asymmetric pulse shapes in electric hearing. J Acoust Soc Am 127 (01) 326-338
    CrossrefPubMedGoogle Scholar
  • Miller CA, Abbas PJ, Robinson BK, Rubinstein JT, Matsuoka AJ. 1999; Electrically evoked single-fiber action potentials from cat: responses to monopolar, monophasic stimulation. Hear Res 130 1–2 197-218
    CrossrefPubMedGoogle Scholar
  • Miller CA, Abbas PJ, Rubinstein JT, Robinson BK, Matsuoka AJ, Woodworth G. 1998; Electrically evoked compound action potentials of guinea pig and cat: responses to monopolar, monophasic stimulation. Hear Res 119 1–2 142-154
    CrossrefPubMedGoogle Scholar
  • Nadol Jr JB. 1997; Patterns of neural degeneration in the human cochlea and auditory nerve: implications for cochlear implantation. Otolaryngol Head Neck Surg 117 (3 Pt 1) 220-228
    CrossrefPubMedGoogle Scholar
  • Nadol Jr JB, Shiao JY, Burgess BJ, Ketten DR, Eddington DK, Gantz BJ, Kos I, Montandon P, Coker NJ, Roland Jr JT, Shallop JK. 2001; Histopathology of cochlear implants in humans. Ann Otol Rhinol Laryngol 110 (09) 883-891
    CrossrefPubMedGoogle Scholar
  • Nadol Jr JB, Young YS, Glynn RJ. 1989; Survival of spiral ganglion cells in profound sensorineural hearing loss: implications for cochlear implantation. Ann Otol Rhinol Laryngol 98 (06) 411-416
    CrossrefPubMedGoogle Scholar
  • Nelson DA, Donaldson GS, Kreft H. 2008; Forward-masked spatial tuning curves in cochlear implant users. J Acoust Soc Am 123 (03) 1522-1543
    CrossrefPubMedGoogle Scholar
  • Ng M, Niparko JK, Nager GT. (2000) Inner ear pathology in severe to profound sensorineural hearing loss. In: Niparko JK, Kirk KI, Mellon NK, Robbins AM, Tucci DL, Wilson BS, editors. Cochlear Implants: Principles and Practices. Philadelphia, PA: Lippincott, Williams and Wilkins, 57–100
  • Rattay F, Lutter P, Felix H. 2001; a A model of the electrically excited human cochlear neuron. I. Contribution of neural substructures to the generation and propagation of spikes. Hear Res 153 1–2 43-63
    CrossrefPubMedGoogle Scholar
  • Rattay F, Leao RN, Felix H. 2001; b A model of the electrically excited human cochlear neuron. II. Influence of the three-dimensional cochlear structure on neural excitability. Hear Res 153 1–2 64-79
    CrossrefPubMedGoogle Scholar
  • Saunders E, Cohen L, Aschendorff A, Shapiro W, Knight M, Stecker M, Richter B, Waltzman S, Tykocinski M, Roland T, Laszig R, Cowan R. 2002; Threshold, comfortable level and impedance changes as a function of electrode-modiolar distance. Ear Hear 23 (01) (Suppl) 28S-40S
    CrossrefPubMedGoogle Scholar
  • Undurraga JA, Carlyon RP, Macherey O, Wouters J, van Wieringen A. 2012; Spread of excitation varies for different electrical pulse shapes and stimulation modes in cochlear implants. Hear Res 290 1–2 21-36
    CrossrefPubMedGoogle Scholar
  • Undurraga JA, Carlyon RP, Wouters J, van Wieringen A. 2013; The polarity sensitivity of the electrically stimulated human auditory nerve measured at the level of the brainstem. J Assoc Res Otolaryngol 14 (03) 359-377
    CrossrefPubMedGoogle Scholar
  • Undurraga JA, van Wieringen A, Carlyon RP, Macherey O, Wouters J. 2010; Polarity effects on neural responses of the electrically stimulated auditory nerve at different cochlear sites. Hear Res 269 1–2 146-161
    CrossrefPubMedGoogle Scholar
  • Zhu Z, Tang Q, Zeng F-G, Guan T, Ye D. 2012; Cochlear-implant spatial selectivity with monopolar, bipolar and tripolar stimulation. Hear Res 283 1–2 45-58
    CrossrefPubMedGoogle Scholar