title: Electric-acoustic pitch comparisons in single-sided-deaf cochlear implant users: frequency-place functions and rate pitch.
abstract: Eight cochlear implant users with near-normal hearing in their non-implanted ear compared pitch percepts for pulsatile electric and acoustic pure-tone stimuli presented to the two ears. Six subjects were implanted with a 31-mm MED-EL FLEX(SOFT) electrode, and two with a 24-mm medium (M) electrode, with insertion angles of the most apical contacts ranging from 565° to 758°. In the first experiment, frequency-place functions were derived from pure-tone matches to 1500-pps unmodulated pulse trains presented to individual electrodes and compared to Greenwood's frequency position map along the organ of Corti. While the overall median downward shift of the obtained frequency-place functions (-0.16 octaves re. Greenwood) and the mean shifts in the basal (<240°; -0.33 octaves) and middle (-0.35 octaves) regions were statistically significant, the shift in the apical region (>480°; 0.26 octaves) was not. Standard deviations of frequency-place functions were approximately half an octave at electrode insertion angles below 480°, increasing to an octave at higher angular locations while individual functions were gradually leveling off. In a second experiment, subjects matched the rates of unmodulated pulse trains presented to individual electrodes in the apical half of the array to low-frequency pure tones between 100 Hz and 450 Hz. The aim was to investigate the influence of electrode place on the salience of temporal pitch cues, for coding strategies that present temporal fine structure information via rate modulations on select apical channels. Most subjects achieved reliable matches to tone frequencies from 100 Hz to 300 Hz only on electrodes at angular insertion depths beyond 360°, while rate-matches to 450-Hz tones were primarily achieved on electrodes at shallower insertion angles. Only for electrodes in the second turn the average slopes of rate-pitch functions did not differ significantly from the pure-tone references, suggesting their use for the encoding of within-channel fine frequency information via rate modulations in temporal fine structure stimulation strategies.
authors.affiliation: Institute of Mechatronics, University of Innsbruck, Technikerstrasse 25, 6020 Innsbruck, Austria. Electronic address: reinhold.schatzer@uibk.ac.at.
authors.forename: Reinhold
authors.initials: R
authors.lastname: Schatzer
authors.affiliation: C. Doppler Laboratory for Active Implantable Systems, Institute of Ion Physics and Applied Physics, University of Innsbruck, Technikerstrasse 25, 6020 Innsbruck, Austria.
authors.forename: Katrien
authors.initials: K
authors.lastname: Vermeire
authors.affiliation: C. Doppler Laboratory for Active Implantable Systems, Institute of Ion Physics and Applied Physics, University of Innsbruck, Technikerstrasse 25, 6020 Innsbruck, Austria.
authors.forename: Daniel
authors.initials: D
authors.lastname: Visser
authors.affiliation: C. Doppler Laboratory for Active Implantable Systems, Institute of Ion Physics and Applied Physics, University of Innsbruck, Technikerstrasse 25, 6020 Innsbruck, Austria.
authors.forename: Andreas
authors.initials: A
authors.lastname: Krenmayr
authors.affiliation: C. Doppler Laboratory for Active Implantable Systems, Institute of Ion Physics and Applied Physics, University of Innsbruck, Technikerstrasse 25, 6020 Innsbruck, Austria.
authors.forename: Mathias
authors.initials: M
authors.lastname: Kals
authors.affiliation: Univ. Dept. of Radiology, University Hospital Antwerp, University of Antwerp, Wilrijkstraat 10, 2650 Edegem, Belgium.
authors.forename: Maurits
authors.initials: M
authors.lastname: Voormolen
authors.affiliation: Univ. Dept. of Otorhinolaryngology, Head and Neck Surgery, University Hospital Antwerp, University of Antwerp, Wilrijkstraat 10, 2650 Edegem, Belgium.
authors.forename: Paul
authors.initials: P
authors.lastname: Van de Heyning
authors.affiliation: Institute of Mechatronics, University of Innsbruck, Technikerstrasse 25, 6020 Innsbruck, Austria.
authors.forename: Clemens
authors.initials: C
authors.lastname: Zierhofer
mesh_terms: D000161:Acoustic Stimulation; D000328:Adult; D001301:Audiometry, Pure-Tone; D019929:Cochlear Implantation / Q000295:instrumentation*; D003054:Cochlear Implants; D012048:Correction of Hearing Impairment / Q000295:instrumentation*; D006311:Hearing Disorders / Q000523:psychology / Q000628:therapy*; D006801:Humans; D008875:Middle Aged; D019986:Persons with Hearing Disabilities / Q000523:psychology / Q000534:rehabilitation*; D010898:Pitch Perception; D011474:Prosthesis Design; D012815:Signal Processing, Computer-Assisted; D055815:Young Adult