J Am Acad Audiol 2001; 12(09): 478-489
DOI: 10.1055/s-0042-1745636
Original Article

Optimizing Electrode and Filter Selection in Cochlear Implant Speech Processor Maps

Katherine R. Henshall
Department of Otolaryngology, The University of Melbourne, Royal Victorian Eye and Ear Hospital, East Melbourne, Australia
Colette M. McKay
Department of Otolaryngology, The University of Melbourne, Royal Victorian Eye and Ear Hospital, East Melbourne, Australia
› Author Affiliations


This study examined two hypotheses: that speech understanding of cochlear implantees could be improved by removing electrodes that exhibit nontonotopic percepts from the speech processor map and that speech understanding could be improved by extending the range of high frequencies that are mapped to the electrodes. Electrodes producing nontonotopic percepts were identified using a multidimensional scaling procedure with seven users of the Nucleus CI22 implant and Spectra processor. Two experimental maps were created with those electrodes removed: the first using the same set of filters as their clinical map and the second using the complete set of filters available. After periods of take-home experience, speech perception was tested and compared for the two experimental maps and their own clinical map. It was found that removing nontonotopic electrodes did not improve speech perception, possibly due to the deleterious side effect of shifting the frequency-to-electrode allocation. Also, extending the high-frequency range of the map did not improve speech perception, possibly due to the poor sensitivity of this processor to high-frequency sounds.

Abbreviations: ANOVA = analysis of variance, CNC = consonant-nucleus-consonant, MDS = multidimensional scaling, SIT = Speech Intelligibility Test, SNR = signal-to-noise ratio

Publication History

Article published online:
07 March 2022

© 2001. American Academy of Audiology. This article is published by Thieme.

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  • Busby PA, Whitford LA, Blarney PJ, Richardson LM, Clark GM. (1994). Pitch perception for different modes of stimulation using the cochlear multiple–electrode prosthesis: J Acoust Soc Am 95:2658–2669.
  • Cochlear Ltd. (1994). Technical Reference Manual. Lane Cove, New South Wales: Cochlear Ltd.
  • Collins LM, Throckmorton CS. (2000). Investigating perceptual features of electrode stimulation via a multidimensional scaling paradigm. J Acoust Soc Am 108:2353–2365.
  • Collins LM, Zwolan T, Wakefield GH. (1997). Comparison of electrode discrimination, pitch ranking, and pitch scaling data in postlingually deafened adult cochlear implant subjects: J Acoust Soc Am 101:440–455.
  • Friesen LM, Shannon RV, Slattery WH. (1999). The effect of frequency allocation on phoneme recognition with the Nucleus 22 cochlear implant. Am J Otol 20:729–734.
  • Fu QJ, Shannon RV. (1999). Effects of electrode configuration and frequency allocation on vowel recognition with the Nucleus–22 cochlear implant. Ear Hear 20:332–344.
  • Henry BA, McDermott HJ, McKay CM, Clark GM. (1998). A frequency importance function for a new monosyllabic word test. Aust J Audiol 20:79—86.
  • Henry BA, McKay CM, McDermott HJ, Clark GM. (2000). The relationship between speech perception and electrode discrimination in cochlear implantees. J Acoust SocAm 108:1269–1280.
  • Levitt H. (1970). Transformed up–down methods in psychoacoustics. J Acoust Soc Am 49:467–477.
  • Magner ME. (1972). A Speech Intelligibility Test for Deaf Children. Northampton, MA: Clarke School for the Deaf.
  • McDermott HJ, McKay CM. (1994). Pitch ranking with nonsimultaneous dual–electrode electrical stimulation of the cochlea. J Acoust SocAm 96:155–162.
  • McKay CM, Carlyon RP. (1999). Dual temporal pitch percepts from acoustic and electric amplitude–modulated pulse trains. J Acoust Soc Am 105:347–357.
  • McKay CM, McDermott HJ, Clark GM. (1996). The perceptual dimensions of single–electrode and non–simultaneous dual–electrode stimuli in cochlear implantees. JAcoust SocAm 99:1079–1090.
  • Peterson G, Lehiste I. (1962). Revised CNC lists for auditory tests. J Speech Hear Disord 27:62–70.
  • Shannon RV. (1983). Multichannel electrical stimulation of the auditory nerve in man. I. Basic psychophysics. Hear Res 11:157–189.
  • Schiffman SS, Reynolds LM, Young FW. (1981). Introduction to Multidimensional Scaling: Theory, Methods and Applications. New York: Academic Press.
  • Skinner MW, Holden LK, Holden TA, Dowell RC, Seligman PM, Brimacombe JA, Beiter AL. (1991). Performance of postlinguistically deaf adults with the Wearable Speech Processor (WSP III) and Mini Speech Processor (MSP) of the Nucleus Multi–Electrode Cochlear Implant. Ear Hear 12:3–22.
  • Skinner MW, Clark GM, Whitford LA, Seligman PM, Staffer SJ, Shipp DB, Shallop JK, Everingham C, Menapace CM, Arndt PL, Antogenelli T, Brimacombe JA, Pijl S, Daniels P, George CR, McDermott HJ, Beiter AL. (1994). Evaluation of a new spectral peak coding strategy for the Nucleus 22 Channel Cochlear Implant System. Am J Otol 15(Suppl 2):15—27.
  • Skinner MW, Holden LK, Holden TA. (1995). Effect of frequency boundary assignment on speech recognition with the SPEAK speech–coding strategy. Ann Otol Rhinol Laryngol Suppl 16:307–311.
  • Skinner MW, Holden LK, Holden TA. (1997). Parameter selection to optimize speech recognition with the Nucleus implant. Otolaryngol Head Neck Surg 117:188–195.
  • Studebaker GA, Sherbecoe RL. (1991). Frequency–importance and transfer functions for recorded CID W–22 word lists. J Speech Hear Res 34:427–438.
  • Tong YC, Clark GM. (1985). Absolute identification of electric pulse rates and electrode positions by cochlear implant patients. J Acoust Soc Am 77:1881–1888.