title: Pitch ranking, electrode discrimination, and physiological spread of excitation using current steering in cochlear implants.
abstract: The first objective of this study was to determine whether adaptive pitch-ranking and electrode-discrimination tasks with cochlear-implant (CI) recipients produce similar results for perceiving intermediate "virtual-channel" pitch percepts using current steering. Previous studies have not examined both behavioral tasks in the same subjects with current steering. A second objective was to determine whether a physiological metric of spatial separation using the electrically evoked compound action potential spread-of-excitation (ECAP SOE) function could predict performance in the behavioral tasks. The metric was the separation index (Σ), defined as the difference in normalized amplitudes between two adjacent ECAP SOE functions, summed across all masker electrodes. Eleven CII or 90 K Advanced Bionics (Valencia, CA) recipients were tested using pairs of electrodes from the basal, middle, and apical portions of the electrode array. The behavioral results, expressed as d', showed no significant differences across tasks. There was also no significant effect of electrode region for either task. ECAP Σ was not significantly correlated with pitch ranking or electrode discrimination for any of the electrode regions. Therefore, the ECAP separation index is not sensitive enough to predict perceptual resolution of virtual channels.
authors.affiliation: Boys Town National Research Hospital, Lied Learning and Technology Center, 425 North 30th Street, Omaha, Nebraska 68131.
authors.forename: Jenny L
authors.initials: JL
authors.lastname: Goehring
authors.affiliation: Boys Town National Research Hospital, Lied Learning and Technology Center, 425 North 30th Street, Omaha, Nebraska 68131.
authors.forename: Donna L
authors.initials: DL
authors.lastname: Neff
authors.affiliation: Boys Town National Research Hospital, Lied Learning and Technology Center, 425 North 30th Street, Omaha, Nebraska 68131.
authors.forename: Jacquelyn L
authors.initials: JL
authors.lastname: Baudhuin
authors.affiliation: Boys Town National Research Hospital, Lied Learning and Technology Center, 425 North 30th Street, Omaha, Nebraska 68131.
authors.forename: Michelle L
authors.initials: ML
authors.lastname: Hughes
mesh_terms: D000161:Acoustic Stimulation; D000328:Adult; D001309:Auditory Threshold / Q000502:physiology; D003051:Cochlea / Q000502:physiology; D003054:Cochlear Implants; D004056:Differential Threshold / Q000502:physiology*; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D008297:Male; D017084:Otoacoustic Emissions, Spontaneous / Q000502:physiology*; D010897:Pitch Discrimination / Q000502:physiology*; D013018:Sound Spectrography