Hearing Loss, CompleteEBCSNCT03726684
Evaluation of a Bio-inspired Coding Strategy for Cochlear Implant Users
A study testing Coding strategy for cochlear implants in people with Hearing Loss, Complete, run by University of Zurich at 1 site in Switzerland.
Trial summary
This study will determine the facilitation, refractoriness and spatial spread effects of auditory nerve fiber responses to electrical stimulation via a cochlear implant. The performance of CI users in melody contour and speech recognition in noise tests with their own clinical sound processor and a MATLAB… Read more about this study
- Who is it for?
- Ages 18 to 80 yearsHealthy volunteers can take part
- Conditions the study is for
- Hearing Loss, Complete
- What is being tested?
- Coding strategy for cochlear implants
- Type of treatment
- Medical device
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 10 participants
- Where
- 1 siteSwitzerland
- Study dates
- 2 Jul 2018to 31 Oct 2018
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 80 years
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- having Nucleus System 4, System 5, System 6 or System 7 sound processor
- having 20 or more active electrodes
- using one of these implant types: System 4, System 5, System 6, System 7
- using ACE coding strategy
- speech recognition score of at least 70% on Oldenburg Speech Test (OLSA) in quiet
- ability to perform an adaptive speech recognition test in noise
Show all 11Show fewer
- experience with their CI for at least six months
- ability for speech understanding in the presence of competing noise without any assistance from lip-reading
- ability to hear differences between musical notes at least for the easiest condition (3 semitones difference between successive notes in a pattern)
- ability to provide subjective feedback in a certain listening situation
- proficiency in reading and writing in German
Who cannot join
- Acute inflammation or pain in head-/neck area
- Dizziness
- Other known illness which would prevent regular participation in test sessions
- Age of participants < 18 years
- Age of participants > 80 years
- Non-standard clinical sound processor program
Trial locations and contacts
1 site in 1 country.
About this study
This study will determine the facilitation, refractoriness and spatial spread effects of auditory nerve fiber responses to electrical stimulation via a cochlear implant.
The performance of CI users in melody contour and speech recognition in noise tests with their own clinical sound processor and a MATLAB implementation of their coding strategy will be compared and a bioinspired coding strategy will be evaluated in comparison with the conventional ACE coding strategy.
Read the detailed description
The advanced combination encoder (ACE) strategy, one of the most widely used clinical speech processing strategies available to cochlear implant (CI) users, attempts to optimize transmission of input acoustic signals, but does not explicitly consider the auditory nerve fibers' (ANFs) capacity for conveying this information. The ACE strategy decomposes temporal frames of the incoming sound signal into frequency bands with a bank of band-pass Fast Fourier Transform (FFT) filters. The temporal envelopes in each band are then extracted and typically eight to ten bands with the highest energy content are selected to amplitude modulate the biphasic pulses. This selection is performed irrespective of the ANFs responses to the electrical stimulation. However, some studies have shown that temporal response properties of ANFs impose limitations for electrical stimulation. Apart from that, the degree of spread of neural excitation which is typically larger than in the acoustic case, may result in responses which can diminish information provided on the individual channels. Thus, a coding strategy taking into account temporal properties of ANFs as well as spatial spread of the electric field could be beneficial for CI users.
One of the prominent temporal characteristics of ANFs in response to the electrical stimulation is refractoriness. This phenomenon can be defined as a reduction in the excitability of ANFs immediately following an action potential and has been observed in CI recipients via measuring the electrically evoked compound action potential (ECAP). The refractory period can be divided into an absolute refractory period (ARP) during which the auditory nerve is incapable of responding to the following pulse and a relative refractory period (RRP) during which a response from the neuron is possible under specific circumstances. Refractoriness can impose limitations on the maximum stimulation rate of CIs since ANFs cannot respond to a stimulus presented during the ARP.
Apart from refractoriness, an ongoing high rate pulse train produces spike rate adaptation (SRA) in ANFs in which the neurons progressively lose their ability to respond to every pulse. This decrement in neural excitability is even larger than can be explained by refractoriness. Animal studies of ANFs at high rate pulse trains have shown SRA and adaptation has also been observed in the ECAP amplitude of human CI users in which the amplitude decreased as the stimulation rate increased. In parallel to spike rate adaptation, accommodation can contribute to the spike rate decrement. Accommodation reduces excitability for the second pulse (probe) response when there is a subthreshold response to the first pulse (masker) and the masker-probe interval (MPI) is large enough to allow the membrane potential to decay back near or below the resting potential. Accommodation in addition to SRA is considered as reduction in the excitability of ANFs and its effect accumulates over sequential non-spiking responses.
Electrical stimulation of ANFs in animals with pairs of pulses has also shown facilitation which is defined as an increase in nerve excitability caused by sub-threshold stimulation in short intervals. Apart from animal studies, the facilitation effect has also been observed in human CI recipients. Facilitation happens when the neuron does not respond to the first pulse, but if the membrane potential remains near the threshold long enough, the second pulse can produce a response. It was shown that facilitation is more evident at a low MPI and for a masker with an intensity equal or less than that of a probe. Although the facilitation effect was observed in human CI users, systematic ECAP measurement to quantify this effect were not yet performed. Thus, neural response telemetry (NRT) measurements with negative masker offset and short MPIs need to be done to determine a non-monotonic behaviour of facilitation and confirm the predictions by Cohen in his model simulations.
Apart from ANFs temporal considerations, electrical current spreads out widely along the cochlea and excites a wide range of populations of ANFs which leads to a decrease in the selectivity and the number of effective channels. Thus, spatial spread of the electric field has a major impact on the spectral resolution of CI users and decreases the excitability of the affected ANF population.
In the planned study refractoriness, spatial spread and facilitation effects will first be determined from NRT measurements with CI participants. Then, all the aforementioned phenomena are integrated in a bio-inspired coding strategy for a better selection of channels with highest energy content. This new strategy will be compared to the conventional ACE coding strategy.
- Conditions
- Hearing Loss, Complete
- Being tested
- Coding strategy for cochlear implants
- Keywords
- cochlear implant, coding strategy, objective measures
- Medical subject headings
- Deafness
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Coding strategy for cochlear implantsDevice
Also called Nucleus Cochlear Implant System
Comparison of two variations of a coding strategy based on electrophysiological objective measures with standard reference coding strategy
| Study group | Role | What they receive |
|---|---|---|
| Coding strategy for cochlear implants | Experimental | Measure neural responses of cochlear implant recipient Use measured values of refractoriness, spread of excitation and facilitation as parameters for a bioinspired coding strategy perform listening tests to compare new coding strategy with standard clinical coding strategy Receives: Device: Coding strategy for cochlear implants |
What is being measured
The primary outcome is the main question the study is designed to answer.
Melody contour identification (MCI) test (% correct)
In the MCI test, five different melody contour patterns with three tones in each pattern are presented in a five alternative forced choice paradigm. The complex tones are synthesized to resemble a clarinet musical instrument. Three separations of fundamental tone frequency varying from one to three semitones are used to vary the difficulties for pattern identification. Every pattern is repeated 10 times in random order which amounts to a total of 150 melody contour presentations per condition. Overall percent correct results and percent correct results for each of the five patterns are determined for the reference and the intervention conditions. Tests are performed with the conventional ACE coding strategy (reference condition) and the bioinspired coding strategy whose parameters are determined from electrophysiological measures of sound-evoked neural responses (intervention condition).
Measured: 6 months
Secondary outcomes (3)
Adaptive Oldenburg sentence test (OLSA) in noise (SRT in dB)
The Adaptive Oldenburg sentence test (OLSA) in noise is used to evaluate speech intelligibility in a noisy environment. The noise level is kept constant at 65 dB sound pressure Level (SPL, in dB) and the speech level is adjusted adaptively to determine the speech reception threshold (SRT, in dB, for 50% speech intelligibility in noise). Lower SRT values indicate better speech recognition in noise. Tests are performed with the conventional ACE coding strategy (reference condition) and the bioinspired coding strategy whose parameters are determined from electrophysiological measures of sound-evoked neural responses (intervention condition).
Measured: 6 months
Time constants (usec) of recovery functions of electrically stimulated auditory nerve fibers, measured by electrically evoked compound action potential (ECAP)
Time constants of recovery functions of electrically stimulated auditory nerve fiber groups can be assessed by ECAP measures through the cochlear implant for various electrode positions. Series of two stimulation pulses are presented whereby the interval between the two pulses is increased from 100 usec to 10'000 usec. The nerve response amplitude grows with increasing interpulse delay from zero up to a saturation level.
Measured: 6 months
Width of spread of excitation function (in mm) of electrically evoked compound action potential (ECAP) measures
Spread of excitation (SOE) is measured with a fixed probe and varying masker electrodes along the electrode array. The width of exponentially fitted SOE curves (in mm) is the main measurement parameter. Outcome variations depend on the amount and distribution of remaining auditory nerve fibers and the geometrical properties of the implanted electrode array relative to the anatomical situation of the patient's inner ear.
Measured: 6 months
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted31 Oct 2018
- Study start2 Jul 2018
- Primary completion31 Oct 2018
- Study completion31 Oct 2018
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (19)Papers the sponsor has linked to this study.
- Other trials for Hearing Loss, CompleteStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Basic science
- Allocation
- Not applicable
- Intervention model
- Single group
- Model description
- Single center, single-armed, parallel design with four laboratory sessions for CI subjects
- Masking
- None (open label)
- Enrolment
- 10 participants (actual)
Sponsor and investigators
- Lead sponsor
- University of Zurich
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
- Investigators
- Norbert Dillier, PhD, Principal investigator, University of Zurich
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT03726684
- Sponsor's protocol ID
- EBCS
- Acronym
- EBCS
- Status last verified
- Nov 2020
- First submitted
- 13 Aug 2018
- Last updated
- 4 Nov 2020
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Publications
Abbas PJ, Hughes ML, Brown CJ, Miller CA, South H. Channel interaction in cochlear implant users evaluated using the electrically evoked compound action potential. Audiol Neurootol. 2004 Jul-Aug;9(4):203-13. doi: 10.1159/000078390.
PubMed 15205548Botros A, Psarros C. Neural response telemetry reconsidered: II. The influence of neural population on the ECAP recovery function and refractoriness. Ear Hear. 2010 Jun;31(3):380-91. doi: 10.1097/AUD.0b013e3181cb41aa.
PubMed 20090532Boulet J, White M, Bruce IC. Temporal Considerations for Stimulating Spiral Ganglion Neurons with Cochlear Implants. J Assoc Res Otolaryngol. 2016 Feb;17(1):1-17. doi: 10.1007/s10162-015-0545-5.
PubMed 26501873Bruce IC, Irlicht LS, White MW, O'Leary SJ, Dynes S, Javel E, Clark GM. A stochastic model of the electrically stimulated auditory nerve: pulse-train response. IEEE Trans Biomed Eng. 1999 Jun;46(6):630-7. doi: 10.1109/10.764939.
PubMed 10356869Cohen LT, Richardson LM, Saunders E, Cowan RS. Spatial spread of neural excitation in cochlear implant recipients: comparison of improved ECAP method and psychophysical forward masking. Hear Res. 2003 May;179(1-2):72-87. doi: 10.1016/s0378-5955(03)00096-0.
PubMed 12742240Cohen LT. Practical model description of peripheral neural excitation in cochlear implant recipients: 5. refractory recovery and facilitation. Hear Res. 2009 Feb;248(1-2):1-14. doi: 10.1016/j.heares.2008.11.007. Epub 2008 Dec 7.
PubMed 19110048Galvin JJ 3rd, Fu QJ, Nogaki G. Melodic contour identification by cochlear implant listeners. Ear Hear. 2007 Jun;28(3):302-19. doi: 10.1097/01.aud.0000261689.35445.20.
PubMed 17485980Heffer LF, Sly DJ, Fallon JB, White MW, Shepherd RK, O'Leary SJ. Examining the auditory nerve fiber response to high rate cochlear implant stimulation: chronic sensorineural hearing loss and facilitation. J Neurophysiol. 2010 Dec;104(6):3124-35. doi: 10.1152/jn.00500.2010. Epub 2010 Oct 6.
PubMed 20926607Hughes ML, Castioni EE, Goehring JL, Baudhuin JL. Temporal response properties of the auditory nerve: data from human cochlear-implant recipients. Hear Res. 2012 Mar;285(1-2):46-57. doi: 10.1016/j.heares.2012.01.010. Epub 2012 Feb 8.
PubMed 22326590Lai W, Dillier N. Neural adaptation and the ECAP response threshold: a pilot study. Cochlear Implants Int. 2009;10 Suppl 1:63-7. doi: 10.1179/cim.2009.10.Supplement-1.63.
PubMed 19194964Miller CA, Abbas PJ, Brown CJ. An improved method of reducing stimulus artifact in the electrically evoked whole-nerve potential. Ear Hear. 2000 Aug;21(4):280-90. doi: 10.1097/00003446-200008000-00003.
PubMed 10981604Miller CA, Abbas PJ, Robinson BK. Response properties of the refractory auditory nerve fiber. J Assoc Res Otolaryngol. 2001 Sep;2(3):216-32. doi: 10.1007/s101620010083.
PubMed 11669395Miller CA, Hu N, Zhang F, Robinson BK, Abbas PJ. Changes across time in the temporal responses of auditory nerve fibers stimulated by electric pulse trains. J Assoc Res Otolaryngol. 2008 Mar;9(1):122-37. doi: 10.1007/s10162-007-0108-5. Epub 2008 Jan 17.
PubMed 18204987Morsnowski A, Charasse B, Collet L, Killian M, Muller-Deile J. Measuring the refractoriness of the electrically stimulated auditory nerve. Audiol Neurootol. 2006;11(6):389-402. doi: 10.1159/000095966. Epub 2006 Sep 27.
PubMed 17008774Negm MH, Bruce IC. The effects of HCN and KLT ion channels on adaptation and refractoriness in a stochastic auditory nerve model. IEEE Trans Biomed Eng. 2014 Nov;61(11):2749-59. doi: 10.1109/TBME.2014.2327055. Epub 2014 May 29.
PubMed 24893366
Study at a glance
From the registry record, last updated by the sponsor on 4 Nov 2020. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Evaluation of a Bio-inspired Coding Strategy for Cochlear Implant Users
- ClinicalTrials.gov ID
- NCT03726684
- Acronym / sponsor ID
- EBCS / EBCS
- Conditions
- Hearing Loss, Complete
- Keywords
- cochlear implant, coding strategy, objective measures
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 10 participants (actual)
- Lead sponsor
- University of ZurichUniversity, hospital or other
- Study start
- 2 Jul 2018 (actual)
- Primary completion
- 31 Oct 2018 (actual)
- Study completion
- 31 Oct 2018 (actual)
- First posted
- 31 Oct 2018 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This study will determine the facilitation, refractoriness and spatial spread effects of auditory nerve fiber responses to electrical stimulation via a cochlear implant.
The performance of CI users in melody contour and speech recognition in noise tests with their own clinical sound processor and a MATLAB implementation of their coding strategy will be compared and a bioinspired coding strategy will be evaluated in comparison with the conventional ACE coding strategy.
Detailed description
The advanced combination encoder (ACE) strategy, one of the most widely used clinical speech processing strategies available to cochlear implant (CI) users, attempts to optimize transmission of input acoustic signals, but does not explicitly consider the auditory nerve fibers' (ANFs) capacity for conveying this information. The ACE strategy decomposes temporal frames of the incoming sound signal into frequency bands with a bank of band-pass Fast Fourier Transform (FFT) filters. The temporal envelopes in each band are then extracted and typically eight to ten bands with the highest energy content are selected to amplitude modulate the biphasic pulses. This selection is performed irrespective of the ANFs responses to the electrical stimulation. However, some studies have shown that temporal response properties of ANFs impose limitations for electrical stimulation. Apart from that, the degree of spread of neural excitation which is typically larger than in the acoustic case, may result in responses which can diminish information provided on the individual channels. Thus, a coding strategy taking into account temporal properties of ANFs as well as spatial spread of the electric field could be beneficial for CI users.
One of the prominent temporal characteristics of ANFs in response to the electrical stimulation is refractoriness. This phenomenon can be defined as a reduction in the excitability of ANFs immediately following an action potential and has been observed in CI recipients via measuring the electrically evoked compound action potential (ECAP). The refractory period can be divided into an absolute refractory period (ARP) during which the auditory nerve is incapable of responding to the following pulse and a relative refractory period (RRP) during which a response from the neuron is possible under specific circumstances. Refractoriness can impose limitations on the maximum stimulation rate of CIs since ANFs cannot respond to a stimulus presented during the ARP.
Apart from refractoriness, an ongoing high rate pulse train produces spike rate adaptation (SRA) in ANFs in which the neurons progressively lose their ability to respond to every pulse. This decrement in neural excitability is even larger than can be explained by refractoriness. Animal studies of ANFs at high rate pulse trains have shown SRA and adaptation has also been observed in the ECAP amplitude of human CI users in which the amplitude decreased as the stimulation rate increased. In parallel to spike rate adaptation, accommodation can contribute to the spike rate decrement. Accommodation reduces excitability for the second pulse (probe) response when there is a subthreshold response to the first pulse (masker) and the masker-probe interval (MPI) is large enough to allow the membrane potential to decay back near or below the resting potential. Accommodation in addition to SRA is considered as reduction in the excitability of ANFs and its effect accumulates over sequential non-spiking responses.
Electrical stimulation of ANFs in animals with pairs of pulses has also shown facilitation which is defined as an increase in nerve excitability caused by sub-threshold stimulation in short intervals. Apart from animal studies, the facilitation effect has also been observed in human CI recipients. Facilitation happens when the neuron does not respond to the first pulse, but if the membrane potential remains near the threshold long enough, the second pulse can produce a response. It was shown that facilitation is more evident at a low MPI and for a masker with an intensity equal or less than that of a probe. Although the facilitation effect was observed in human CI users, systematic ECAP measurement to quantify this effect were not yet performed. Thus, neural response telemetry (NRT) measurements with negative masker offset and short MPIs need to be done to determine a non-monotonic behaviour of facilitation and confirm the predictions by Cohen in his model simulations.
Apart from ANFs temporal considerations, electrical current spreads out widely along the cochlea and excites a wide range of populations of ANFs which leads to a decrease in the selectivity and the number of effective channels. Thus, spatial spread of the electric field has a major impact on the spectral resolution of CI users and decreases the excitability of the affected ANF population.
In the planned study refractoriness, spatial spread and facilitation effects will first be determined from NRT measurements with CI participants. Then, all the aforementioned phenomena are integrated in a bio-inspired coding strategy for a better selection of channels with highest energy content. This new strategy will be compared to the conventional ACE coding strategy.
Study design
- Primary purpose
- Basic science
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
- Model description
- Single center, single-armed, parallel design with four laboratory sessions for CI subjects
| Arm | Type | Receives |
|---|---|---|
| Coding strategy for cochlear implants | Experimental | Device: Coding strategy for cochlear implantsMeasure neural responses of cochlear implant recipient Use measured values of refractoriness, spread of excitation and facilitation as parameters for a bioinspired coding strategy perform listening tests to compare new coding strategy with standard clinical coding strategy |
Who may qualify
- Ages
- 18 to 80 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (11 listed)
- having Nucleus System 4, System 5, System 6 or System 7 sound processor
- having 20 or more active electrodes
- using one of these implant types: System 4, System 5, System 6, System 7
- using ACE coding strategy
- speech recognition score of at least 70% on Oldenburg Speech Test (OLSA) in quiet
Key exclusion criteria (6 listed)
- Acute inflammation or pain in head-/neck area
- Dizziness
- Other known illness which would prevent regular participation in test sessions
- Age of participants < 18 years
- Age of participants > 80 years
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Coding strategy for cochlear implantsAlso: Nucleus Cochlear Implant SystemComparison of two variations of a coding strategy based on electrophysiological objective measures with standard reference coding strategy | Device | Coding strategy for cochlear implants |
Primary outcome
Melody contour identification (MCI) test (% correct)
Time frame: 6 months
In the MCI test, five different melody contour patterns with three tones in each pattern are presented in a five alternative forced choice paradigm. The complex tones are synthesized to resemble a clarinet musical instrument. Three separations of fundamental tone frequency varying from one to three semitones are used to vary the difficulties for pattern identification. Every pattern is repeated 10 times in random order which amounts to a total of 150 melody contour presentations per condition. Overall percent correct results and percent correct results for each of the five patterns are determined for the reference and the intervention conditions. Tests are performed with the conventional ACE coding strategy (reference condition) and the bioinspired coding strategy whose parameters are determined from electrophysiological measures of sound-evoked neural responses (intervention condition).
3 secondary outcomes
Adaptive Oldenburg sentence test (OLSA) in noise (SRT in dB)
Time frame: 6 months
Time constants (usec) of recovery functions of electrically stimulated auditory nerve fibers, measured by electrically evoked compound action potential (ECAP)
Time frame: 6 months
Width of spread of excitation function (in mm) of electrically evoked compound action potential (ECAP) measures
Time frame: 6 months
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 4 Nov 2020.
- Background: PubMed 15205548Abbas PJ, Hughes ML, Brown CJ, Miller CA, South H. Channel interaction in cochlear implant users evaluated using the electrically evoked compound action potential. Audiol Neurootol. 2004 Jul-Aug;9(4):203-13. doi: 10.1159/000078390.
- Background: PubMed 20090532Botros A, Psarros C. Neural response telemetry reconsidered: II. The influence of neural population on the ECAP recovery function and refractoriness. Ear Hear. 2010 Jun;31(3):380-91. doi: 10.1097/AUD.0b013e3181cb41aa.
- Background: PubMed 26501873Boulet J, White M, Bruce IC. Temporal Considerations for Stimulating Spiral Ganglion Neurons with Cochlear Implants. J Assoc Res Otolaryngol. 2016 Feb;17(1):1-17. doi: 10.1007/s10162-015-0545-5.
- Background: PubMed 10356869Bruce IC, Irlicht LS, White MW, O'Leary SJ, Dynes S, Javel E, Clark GM. A stochastic model of the electrically stimulated auditory nerve: pulse-train response. IEEE Trans Biomed Eng. 1999 Jun;46(6):630-7. doi: 10.1109/10.764939.
- Background: PubMed 12742240Cohen LT, Richardson LM, Saunders E, Cowan RS. Spatial spread of neural excitation in cochlear implant recipients: comparison of improved ECAP method and psychophysical forward masking. Hear Res. 2003 May;179(1-2):72-87. doi: 10.1016/s0378-5955(03)00096-0.
- Background: PubMed 19110048Cohen LT. Practical model description of peripheral neural excitation in cochlear implant recipients: 5. refractory recovery and facilitation. Hear Res. 2009 Feb;248(1-2):1-14. doi: 10.1016/j.heares.2008.11.007. Epub 2008 Dec 7.
- Background: PubMed 17485980Galvin JJ 3rd, Fu QJ, Nogaki G. Melodic contour identification by cochlear implant listeners. Ear Hear. 2007 Jun;28(3):302-19. doi: 10.1097/01.aud.0000261689.35445.20.
- Background: PubMed 20926607Heffer LF, Sly DJ, Fallon JB, White MW, Shepherd RK, O'Leary SJ. Examining the auditory nerve fiber response to high rate cochlear implant stimulation: chronic sensorineural hearing loss and facilitation. J Neurophysiol. 2010 Dec;104(6):3124-35. doi: 10.1152/jn.00500.2010. Epub 2010 Oct 6.
- Background: PubMed 22326590Hughes ML, Castioni EE, Goehring JL, Baudhuin JL. Temporal response properties of the auditory nerve: data from human cochlear-implant recipients. Hear Res. 2012 Mar;285(1-2):46-57. doi: 10.1016/j.heares.2012.01.010. Epub 2012 Feb 8.
- Background: PubMed 19194964Lai W, Dillier N. Neural adaptation and the ECAP response threshold: a pilot study. Cochlear Implants Int. 2009;10 Suppl 1:63-7. doi: 10.1179/cim.2009.10.Supplement-1.63.
- Background: PubMed 10981604Miller CA, Abbas PJ, Brown CJ. An improved method of reducing stimulus artifact in the electrically evoked whole-nerve potential. Ear Hear. 2000 Aug;21(4):280-90. doi: 10.1097/00003446-200008000-00003.
- Background: PubMed 11669395Miller CA, Abbas PJ, Robinson BK. Response properties of the refractory auditory nerve fiber. J Assoc Res Otolaryngol. 2001 Sep;2(3):216-32. doi: 10.1007/s101620010083.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Norbert Dillier, PhD principal investigator
University of Zurich
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Coding strategy for cochlear implants in people with Hearing Loss, Complete, run by University of Zurich at 1 site in Switzerland.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 11 inclusion and 6 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 4 Nov 2020. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Switzerland. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Melody contour identification (MCI) test (% correct) (time frame: 6 months). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT03726684, which also lists 19 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 4 Nov 2020.