Effects of phase duration and electrode separation on loudness growth in cochlear implant listeners

2000 ◽  
Vol 107 (3) ◽  
pp. 1637-1644 ◽  
Author(s):  
Monita Chatterjee ◽  
Qian-Jie Fu ◽  
Robert V. Shannon
Keyword(s):  
Cochlear Implant ◽  
Phase Duration ◽  
Electrode Separation ◽  
Loudness Growth

scholarly journals Effect of pulse phase duration on forward masking and spread of excitation in cochlear implant listeners

PLoS ONE ◽  
2020 ◽  
Vol 15 (7) ◽  
pp. e0236179
Author(s):  
Ning Zhou ◽  
Zhen Zhu ◽  
Lixue Dong ◽  
John J. Galvin
Keyword(s):  
Cochlear Implant ◽  
Forward Masking ◽  
Phase Duration ◽  
Pulse Phase ◽  
Spread Of Excitation

scholarly journals Relationships Between Electrically Evoked Potentials and Loudness Growth in Bilateral Cochlear Implant Users

2012 ◽  
Vol 33 (3) ◽  
pp. 389-398 ◽  
Author(s):  
Benjamin Kirby ◽  
Carolyn Brown ◽  
Paul Abbas ◽  
Christine Etler ◽  
Sara O’Brien
Keyword(s):  
Cochlear Implant ◽  
Evoked Potentials ◽  
Bilateral Cochlear Implant ◽  
Electrically Evoked Potentials ◽  
Loudness Growth

scholarly journals Recognition and Localization of Speech by Adult Cochlear Implant Recipients Wearing a Digital Hearing Aid in the Nonimplanted Ear (Bimodal Hearing)

2009 ◽  
Vol 20 (06) ◽  
pp. 353-373 ◽  
Author(s):  
Lisa G. Potts ◽  
Margaret W. Skinner ◽  
Ruth A. Litovsky ◽  
Michael J. Strube ◽  
Francis Kuk
Keyword(s):  
Speech Recognition ◽  
Cochlear Implant ◽  
Repeated Measures ◽  
Dynamic Range ◽  
Hearing Aid ◽  
Bilateral Stimulation ◽  
Bimodal Condition ◽  
Digital Hearing Aid ◽  
Loudness Growth ◽  
Bimodal Hearing

Background: The use of bilateral amplification is now common clinical practice for hearing aid users but not for cochlear implant recipients. In the past, most cochlear implant recipients were implanted in one ear and wore only a monaural cochlear implant processor. There has been recent interest in benefits arising from bilateral stimulation that may be present for cochlear implant recipients. One option for bilateral stimulation is the use of a cochlear implant in one ear and a hearing aid in the opposite nonimplanted ear (bimodal hearing). Purpose: This study evaluated the effect of wearing a cochlear implant in one ear and a digital hearing aid in the opposite ear on speech recognition and localization. Research Design: A repeated-measures correlational study was completed. Study Sample: Nineteen adult Cochlear Nucleus 24 implant recipients participated in the study. Intervention: The participants were fit with a Widex Senso Vita 38 hearing aid to achieve maximum audibility and comfort within their dynamic range. Data Collection and Analysis: Soundfield thresholds, loudness growth, speech recognition, localization, and subjective questionnaires were obtained six–eight weeks after the hearing aid fitting. Testing was completed in three conditions: hearing aid only, cochlear implant only, and cochlear implant and hearing aid (bimodal). All tests were repeated four weeks after the first test session. Repeated-measures analysis of variance was used to analyze the data. Significant effects were further examined using pairwise comparison of means or in the case of continuous moderators, regression analyses. The speech-recognition and localization tasks were unique, in that a speech stimulus presented from a variety of roaming azimuths (140 degree loudspeaker array) was used. Results: Performance in the bimodal condition was significantly better for speech recognition and localization compared to the cochlear implant–only and hearing aid–only conditions. Performance was also different between these conditions when the location (i.e., side of the loudspeaker array that presented the word) was analyzed. In the bimodal condition, the speech-recognition and localization tasks were equal regardless of which side of the loudspeaker array presented the word, while performance was significantly poorer for the monaural conditions (hearing aid only and cochlear implant only) when the words were presented on the side with no stimulation. Binaural loudness summation of 1–3 dB was seen in soundfield thresholds and loudness growth in the bimodal condition. Measures of the audibility of sound with the hearing aid, including unaided thresholds, soundfield thresholds, and the Speech Intelligibility Index, were significant moderators of speech recognition and localization. Based on the questionnaire responses, participants showed a strong preference for bimodal stimulation. Conclusions: These findings suggest that a well-fit digital hearing aid worn in conjunction with a cochlear implant is beneficial to speech recognition and localization. The dynamic test procedures used in this study illustrate the importance of bilateral hearing for locating, identifying, and switching attention between multiple speakers. It is recommended that unilateral cochlear implant recipients, with measurable unaided hearing thresholds, be fit with a hearing aid.

scholarly journals Sensitivity to Pulse Phase Duration as a Marker of Neural Health Across Cochlear Implant Recipients and Electrodes

2021 ◽  
Author(s):  
Ning Zhou ◽  
Zhen Zhu ◽  
Lixue Dong ◽  
John Galvin
Keyword(s):  
Hearing Loss ◽  
Speech Recognition ◽  
Cochlear Implant ◽  
Dynamic Range ◽  
Recognition Performance ◽  
Phase Duration ◽  
Pulse Phase ◽  
Site Variation ◽  
Integration Efficiency ◽  
Charge Integration

AbstractIn cochlear implants, loudness has been shown to grow more slowly with increasing pulse phase duration (PPD) than with pulse amplitude (PA), possibly due to “leaky” charge integration. This leakiness has been recently quantified in terms of “charge integration efficiency,” defined as the log difference between the PPD dynamic range and PA dynamic range (both expressed in charge units), relative to a common threshold anchor. Such leakiness may differ across electrodes and/or test ears, and may reflect underlying neural health. In this study, we examined the across-site variation of charge integration in recipients of Cochlear© devices. PPD and PA dynamic ranges were measured relative to two threshold anchors with either a 25- or 50-microsecond PPD. Strength-duration functions, previously shown to relate to survival of spiral ganglion cells and peripheral processes, were compared to charge integration efficiency on selected electrodes. Results showed no significant or systematic relationship between the across-site variation in charge integration efficiency and electrode position or threshold levels. Charge integration efficiency was poorer with the 50-μs threshold anchor, suggesting that greater leakiness was associated with larger PPD dynamic ranges. Poorer and more variable charge integration efficiency across electrodes was associated with longer duration of any hearing loss, consistent with the idea that poor integration is related to neural degeneration. More variable integration efficiency was also associated with poorer speech recognition performance across test ears. The slopes of the strength-duration functions at maximum acceptable loudness were significantly correlated with charge integration efficiency. However, the strength-duration slopes were not predictive of duration of any hearing loss or speech recognition performance in our participants. As such, charge integration efficiency may be a better candidate to measure leakiness in neural populations across the electrode array, as well as the general health of the auditory nerve in human cochlear implant recipients.

scholarly journals Effect of Pulse Polarity on Thresholds and on Non-monotonic Loudness Growth in Cochlear Implant Users

2017 ◽  
Vol 18 (3) ◽  
pp. 513-527 ◽  
Author(s):  
Olivier Macherey ◽  
Robert P. Carlyon ◽  
Jacques Chatron ◽  
Stéphane Roman
Keyword(s):  
Cochlear Implant ◽  
Pulse Polarity ◽  
Loudness Growth
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