Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

  • Article
  • Published:

Enhancement of vowel coding for cochlear implants by addition of noise

Nature Medicine volume 2, pages 928–932 (1996)Cite this article

Abstract

Profoundly deaf people, who gain no benefit from conventional hearing aids, can receive speech cues by direct electrical stimulation of the cochlear nerve1,2. This is achieved by an electronic device, a cochlear implant, which is surgically inserted into the ear. Here we show physiological results from the isolated sciatic nerve of the toad Xenopus laevis, used to predict the response of the human cochlear nerve to vowels coded by a cochlear implant. These results suggest that standard analogue cochlear implants do not evoke the patterns of neural excitation that are normally associated with acoustic stimulation. Adding noise to the stimulus, however, enhanced distinguishing features of the vowel encoded by the fine time structure of neural discharges. On the basis of these results, and those concerning stochastic resonance3–5, we advocate a cochlear implant coding strategy in which noise is deliberately added to cochlear implant signals.

This is a preview of subscription content, access via your institution

Access options

Buy this article

  • Purchase on Springer Link
  • Instant access to full article PDF
Buy now

Prices may be subject to local taxes which are calculated during checkout

Similar content being viewed by others

References

  1. Bilger, R.C. et al. Evaluation of subjects presently fitted with implanted auditory prostheses. Ann. Otol. Rhinol. Laryngol. 86, suppl. 38, 1–176 (1977).

    Google Scholar 

  2. Tyler, R.S., Moore, B.C.J. & Kuk, F.K. Performance of some of the better cochlear-implant patients. J. Speech Hear. Res. 32, 887–911 (1989).

    Article  CAS  Google Scholar 

  3. Wiesenfeld, K. & Moss, F. Stochastic resonance and the benefits of noise: from ice ages to crayfish and SQUIDs. Nature 373, 33–36 (1995).

    Article  CAS  Google Scholar 

  4. Moss, F. & Pei, X. Neurons in parallel. Nature 376, 211–212 (1995).

    Article  CAS  Google Scholar 

  5. Collins, J.J., Chow, C.C. & Imhoff, T.T. Stochastic resonance without tuning. Nature 376, 236–238 (1995).

    Article  CAS  Google Scholar 

  6. Evans, E.F. Place and time coding of frequency in the peripheral auditory system: Some physiological pros and cons. Audiology 17, 369–420 (1978).

    Article  CAS  Google Scholar 

  7. Kiang, N.Y.S., Moxon, E.C. & Levine, R.A. Auditory nerve activity in cats with normal and abnormal cochleae. in Sensorineural Hearing Loss (eds. Wolstenholme, G.E.W. & Knight, J.) 241–273 (Churchill, London, 1970).

    Google Scholar 

  8. Evans, E.F. The frequency response and other properties of single fibres in the guinea pig cochlear nerve. J. Physiol. (Lond.) 226, 263–287 (1972).

    Article  CAS  Google Scholar 

  9. Kiang, N.Y.S., Watanabe, T., Thomas, E.G. & Clark, L.F. Discharge Patterns of Single Fibres in the Cat's Auditory Nerve. (M.I.T. Press, Cambridge, Massachusetts, 1965).

    Google Scholar 

  10. Knauth, M., Hartmann, R. & Klinke, R. Discharge pattern in the auditory nerve evoked by vowel stimuli: A comparison between acoustical and electrical stimulation. Hear. Res. 74, 247–258 (1994).

    Article  CAS  Google Scholar 

  11. Clopton, B.M. & Glass, I. Unit responses at cochlear nucleus to electrical stimulation through a cochlear prosthesis. Hear. Res. 14, 1–11 (1984).

    Article  CAS  Google Scholar 

  12. Frankenhaeuser, B. & Huxley, A.F. The action potential in the myelinated nerve fibre of Xenopus laevis as computed on the basis of voltage clamp data. J. Physiol. (Lond.) 171, 302–315 (1964).

    Article  CAS  Google Scholar 

  13. Roper, J. & Schwarz, J.R. Heterogeneous distribution of fast and slow potassium channels in myelinated rat nerve fibres. J. Physiol. (Lond.) 416, 93–110 (1989).

    Article  CAS  Google Scholar 

  14. Dubois, J.M. Evidence for the existence of three types of potassium channels in the frog Ranvier node membrane. J. Physiol. (Lond.) 318, 297–316 (1981).

    Article  CAS  Google Scholar 

  15. Schwarz, J.R., Reid, G. & Bostock, H. Action potentials and membrane currents in human node of Ranvier. Pflugers Arch. 430, 283–292 (1995).

    Article  CAS  Google Scholar 

  16. Bretag, A.H. & Stämpfli, R. Differences in action potentials and accommodation of sensory and motor myelinated nerve fibres as computed on the basis of voltage clamp data. Pflügers Arch. 354, 257–271 (1975).

    Article  CAS  Google Scholar 

  17. Hill, A.V., Katz, B. & Solandt, D.Y. Nerve excitation by alternating current. Proc. R. Soc. Lond. B 121, 74–133 (1936).

    Article  Google Scholar 

  18. Kiang, N.Y.S. & Moxon, E.G. Physiological considerations in artificial stimulation of the inner ear. Ann. Otol. Rhinol. Laryngol. 81, 714–730 (1972).

    Article  CAS  Google Scholar 

  19. Shannon, R.V. Multichannel electrical stimulation of the auditory nerve in man. I. Basic psychophysics. Hear. Res. 11, 157–189 (1983).

    Article  CAS  Google Scholar 

  20. Goldberg, J.M. & Brownell, W.E. Discharge characteristics of neurons in the anteroventral and dorsal cochlear nucleus of cat. Brain Res. 64, 35–54 (1973).

    Article  CAS  Google Scholar 

  21. Young, E.D. & Sachs, M.B. Representation of steady-state vowels in the temporal aspects of the discharge patterns of populations of auditory-nerve fibres. J. Acoust. Soc. Am. 66, 1381–1403 (1979).

    Article  CAS  Google Scholar 

  22. Delgutte, B. & Kiang, N.Y.S. Speech coding in the auditory nerve. I. Vowel-like sounds. J. Acoust. Soc. Am. 75, 866–878 (1984).

    Article  CAS  Google Scholar 

  23. Wilson, B.S. et al. Present status and future enhancements of the UCSF cochlear prosthesis. in Cochlear Implant: Current Situation (ed. Banfai, P.) 395–427 (Rudolf Bermann, Erkeleng, 1988).

    Google Scholar 

  24. Parkin, J.L. & Stewart, B.E. Multichannel cochlear implantation: Utah design. Laryngoscope 98, 262–265 (1988).

    Article  CAS  Google Scholar 

  25. Simmons, F.B. Electrical stimulation of the auditory nerve in man. Arch. Otolaryngol. 84, 2–54 (1966).

    Article  CAS  Google Scholar 

  26. Spoendlin, H. & Schrott, A. Analysis of the human auditory nerve. Hear. Res. 43, 25–38 (1989).

    Article  CAS  Google Scholar 

  27. Erlanger, J. & Gasser, H.S. Electrical Signs of Nervous Activity. (Univ. Philadelphia Press, Philadelphia, 1937).

    Google Scholar 

  28. Rushton, W.A.H. A theory of the effects of fibre diameter in medullated nerve. J. Physiol. (Lond.) 115, 101–122 (1951).

    Article  CAS  Google Scholar 

  29. Douglass, J.K., Wilkens, L., Pantazelou, E. & Moss, F. Noise enhancement of the information transfer in crayfish mechanoreceptors by stochastic resonance. Nature 365, 337–340 (1993).

    Article  CAS  Google Scholar 

  30. Levin, J.E. & Miller, J.P. Broadband neural coding in the cricket cereal sensory system enhanced by stochastic resonance. Nature 380, 165–168 (1996).

    Article  CAS  Google Scholar 

  31. Gingl, Z., Kiss, L.B. & Moss, F. Non-dynamical stochastic resonance: Theory and experiments with white and arbitrary coloured noise. Europhys. Lett. 29, 191–196 (1995).

    Article  CAS  Google Scholar 

  32. Benzi, R., Sultera, S. & Vulpiani, A. The mechanism of stochastic resonance. J. Phys. A Math. Gen. 14, L453–L457 (1981).

    Article  Google Scholar 

  33. Fauve, S. & Heslot, F. Stochastic resonance in a bistable system. Phys. Lett. 97A, 5–7 (1983).

    Article  Google Scholar 

  34. McNamara, B., Wiesenfeld, K. & Roy, R. Observation of stochastic resonance in ring laser. Phys. Rev. Lett. 60, 2626–2629 (1988).

    Google Scholar 

  35. Dodge, F.A. & Frankenhaeuser, B. Membrane currents in the isolated frog nerve fibre under voltage clamp conditions. J. Physiol. (Lond.) 143, 76–90 (1958).

    Article  CAS  Google Scholar 

  36. Klatt, D.H. Software for a cascade/parallel formant synthesizer. J. Acoust. Soc. Am. 67, 971–995 (1980).

    Article  Google Scholar 

Download references

Author information

Authors and Affiliations

  1. Department of Communication and Neuroscience, Keele University, Keele, Staffordshire, ST5 5BG, UK

    Robert P. Morse & Edward F. Evans

Authors
  1. Robert P. Morse
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Edward F. Evans
    View author publications

    You can also search for this author in PubMed Google Scholar

Rights and permissions

Reprints and permissions

About this article

Cite this article

Morse, R., Evans, E. Enhancement of vowel coding for cochlear implants by addition of noise. Nat Med 2, 928–932 (1996). https://doi.org/10.1038/nm0896-928

Download citation

  • Received:

  • Accepted:

  • Issue Date:

  • DOI: https://doi.org/10.1038/nm0896-928

This article is cited by

Search

Advanced search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing