Journal article
Changes in Pitch with a Cochlear Implant Over Time
Journal of the Association for Research in Otolaryngology, Vol.8(2), pp.241-257
06/2007
DOI: 10.1007/s10162-007-0077-8
PMCID: PMC2538353
PMID: 17347777
Abstract
In the normal auditory system, the perceived pitch of a tone is closely linked to the cochlear place of vibration. It has generally been assumed that high-rate electrical stimulation by a cochlear implant electrode also evokes a pitch sensation corresponding to the electrode’s cochlear place (“place” code) and stimulation rate (“temporal” code). However, other factors may affect electric pitch sensation, such as a substantial loss of nearby nerve fibers or even higher-level perceptual changes due to experience. The goals of this study were to measure electric pitch sensations in hybrid (short-electrode) cochlear implant patients and to examine which factors might contribute to the perceived pitch. To look at effects of experience, electric pitch sensations were compared with acoustic tone references presented to the non-implanted ear at various stages of implant use, ranging from hookup to 5 years. Here, we show that electric pitch perception often shifts in frequency, sometimes by as much as two octaves, during the first few years of implant use. Additional pitch measurements in more recently implanted patients at shorter time intervals up to 1 year of implant use suggest two likely contributions to these observed pitch shifts: intersession variability (up to one octave) and slow, systematic changes over time. We also found that the early pitch sensations for a constant electrode location can vary greatly across subjects and that these variations are strongly correlated with speech reception performance. Specifically, patients with an early low-pitch sensation tend to perform poorly with the implant compared to those with an early high-pitch sensation, which may be linked to less nerve survival in the basal end of the cochlea in the low-pitch patients. In contrast, late pitch sensations show no correlation with speech perception. These results together suggest that early pitch sensations may more closely reflect peripheral innervation patterns, while later pitch sensations may reflect higher-level, experience-dependent changes. These pitch shifts over time not only raise questions for strict place-based theories of pitch perception, but also imply that experience may have a greater influence on cochlear implant perception than previously thought.
Details
- Title: Subtitle
- Changes in Pitch with a Cochlear Implant Over Time
- Creators
- Lina A.J Reiss - Department of Speech Pathology and Audiology, Wendell Johnson Speech and Hearing Center, University of Iowa, Iowa City, IA 52242 USAChristopher W Turner - Department of Speech Pathology and Audiology, Wendell Johnson Speech and Hearing Center, University of Iowa, Iowa City, IA 52242 USASheryl R Erenberg - Department of Speech Pathology and Audiology, Wendell Johnson Speech and Hearing Center, University of Iowa, Iowa City, IA 52242 USABruce J Gantz - Department of Otolaryngology-Head Neck Surgery, University of Iowa, Iowa City, IA 52242 USA
- Resource Type
- Journal article
- Publication Details
- Journal of the Association for Research in Otolaryngology, Vol.8(2), pp.241-257
- Publisher
- Springer-Verlag; New York
- DOI
- 10.1007/s10162-007-0077-8
- PMID
- 17347777
- PMCID
- PMC2538353
- ISSN
- 1525-3961
- eISSN
- 1438-7573
- Language
- English
- Date published
- 06/2007
- Academic Unit
- Communication Sciences and Disorders; Neurosurgery; Otolaryngology
- Record Identifier
- 9984006436602771
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