Novel Coding Strategies for Children With Cochlear Implants

Study Overview
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Brief Summary
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The purpose of this study is to understand performance with a cochlear implant. The long-term goals of this research are to improve sound perception with cochlear implants and to better understand the functioning of the auditory system. Information from individuals with and without cochlear implants will be compared.

Detailed Description
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The overall objectives of this research are to 1) gain a better understanding of fundamental psychophysical abilities with electrical stimulation as a function of age (child vs adult), age at onset of deafness (pre- vs post-lingual), and acoustic hearing (normal vs limited or residual); and 2) determine whether manipulations in CI coding strategies will improve psychophysical and speech recognition outcomes for early implanted children. This work is expected to provide new insights into the corresponding improvements in perceptual outcomes to these newer strategies have been modest at best and performance has begun to level off.

Official Title
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Novel Coding Strategies for Children With Cochlear Implants

Conditions
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Deafness

Intervention / Treatment
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* Other: Single-Electrode Pulse Train
* Other: Modulation Detection Threshold (MDT) and Gap Detection Tasks
* Other: Sound coding strategy.
* Other: Electric-only spectral resolution


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Be 7 years of age or older and pre-lingually implanted with a cochlear implant (before the age of 2 years), have aided residual hearing, or have normal hearing. Be ages 18 or older and post-lingually implanted or have normal hearing. Be ages 18-35 and pre-lingually implanted. Exclusion Criteria: Any child implanted post-lingually

Ages Eligible for Study
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Minimum Age: 6 Years
Maximum Age: 80 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Non-Randomized
Intervention Model: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Late Adult Cochlear Implant (LateAdultCI)<br>Post-lingually implanted adults, 18+ years | Other: Single-Electrode Pulse Train<br>* AIM 2 - Stimuli will be presented on one of three electrodes (apical, middle, and basal) at an amplitude between 10 and 100% dynamic range in µAs in 10% dynamic range steps. Stimulation will be delivered at a rate of 1000 pps. The process will be repeated in random order until 20 loudness estimates are obtained for each stimulus (3 electrodes x 2 rates x 10 amplitudes) for each subject. The dynamic range will be determined by measuring the maximum acceptable loudness (MAL) and threshold for each of the stimuli. MAL will be measured by slowly raising the current level for each stimulus until the subject reports that it is as loud as they are willing to accept without becoming uncomfortably loud.<br>Other: Modulation Detection Threshold (MDT) and Gap Detection Tasks<br>* AIM 1 - MDT will be set at 150 Hz. Testing will be conducted in soundfield in a sound booth at 60 dB Sound Pressure Level (SPL) while the participant listens with both implants adjusted to user setting.<br>Other: Sound coding strategy.<br>* Aim3 - Spectral-temporally modulated ripple test (SMRT), Quick Spectral Modulation Detection (QSMD), Modulation Detection, Gap Detection. CNC words will be set in quiet and Az-Bio/BabyBio sentences in quiet and multi-talker babble (+10 and +5 dB SNR) using both the subject's clinical map and the new reduced channels map. Tests will be presented in the soundfield at 60 dB SPL<br>|
| Experimental: Early Child Cochlear Implant (EarlyChildCI)<br>Early implanted children, ages 7-17 years | Other: Modulation Detection Threshold (MDT) and Gap Detection Tasks<br>* AIM 1 - MDT will be set at 150 Hz. Testing will be conducted in soundfield in a sound booth at 60 dB Sound Pressure Level (SPL) while the participant listens with both implants adjusted to user setting.<br>Other: Sound coding strategy.<br>* Aim3 - Spectral-temporally modulated ripple test (SMRT), Quick Spectral Modulation Detection (QSMD), Modulation Detection, Gap Detection. CNC words will be set in quiet and Az-Bio/BabyBio sentences in quiet and multi-talker babble (+10 and +5 dB SNR) using both the subject's clinical map and the new reduced channels map. Tests will be presented in the soundfield at 60 dB SPL<br>Other: Electric-only spectral resolution<br>* Aim 1- Spectral resolution will be tested using frequency allocations consisting of the full default clinical range as well as the subject's clinical frequency allocation if they differ. For Hybrid electrode users in which electrode contacts are closer in proximity in the cochlea, maps with a frequency allocation of 938-7938 Hz will also be tested in that it will closely approximate the frequency spacing of a Nucleus Contour Advance electrode array. Spectral resolution will be measured with three repetitions of the SMRT and one repetition of the QSMD test. Testing will be presented at 60 dB SPL in the soundfield with the acoustic ear plugged and muffed.<br>|
| Experimental: Early Adult Cochlear Implant (EarlyAdultCI)<br>Early implanted adults, ages 18 to 35 years | Other: Single-Electrode Pulse Train<br>* AIM 2 - Stimuli will be presented on one of three electrodes (apical, middle, and basal) at an amplitude between 10 and 100% dynamic range in µAs in 10% dynamic range steps. Stimulation will be delivered at a rate of 1000 pps. The process will be repeated in random order until 20 loudness estimates are obtained for each stimulus (3 electrodes x 2 rates x 10 amplitudes) for each subject. The dynamic range will be determined by measuring the maximum acceptable loudness (MAL) and threshold for each of the stimuli. MAL will be measured by slowly raising the current level for each stimulus until the subject reports that it is as loud as they are willing to accept without becoming uncomfortably loud.<br>Other: Sound coding strategy.<br>* Aim3 - Spectral-temporally modulated ripple test (SMRT), Quick Spectral Modulation Detection (QSMD), Modulation Detection, Gap Detection. CNC words will be set in quiet and Az-Bio/BabyBio sentences in quiet and multi-talker babble (+10 and +5 dB SNR) using both the subject's clinical map and the new reduced channels map. Tests will be presented in the soundfield at 60 dB SPL<br>|
| Experimental: Cochlear Implant (CI)<br>CI children, ages 7-17 years, with aided residual hearing (bimodal/contralateral, electric+acoustic/ipsilateral) | Other: Electric-only spectral resolution<br>* Aim 1- Spectral resolution will be tested using frequency allocations consisting of the full default clinical range as well as the subject's clinical frequency allocation if they differ. For Hybrid electrode users in which electrode contacts are closer in proximity in the cochlea, maps with a frequency allocation of 938-7938 Hz will also be tested in that it will closely approximate the frequency spacing of a Nucleus Contour Advance electrode array. Spectral resolution will be measured with three repetitions of the SMRT and one repetition of the QSMD test. Testing will be presented at 60 dB SPL in the soundfield with the acoustic ear plugged and muffed.<br>|
| Active Comparator: Normal Hearing Children (NHC)<br>Ages 7-17 years, Control Group | Other: Modulation Detection Threshold (MDT) and Gap Detection Tasks<br>* AIM 1 - MDT will be set at 150 Hz. Testing will be conducted in soundfield in a sound booth at 60 dB Sound Pressure Level (SPL) while the participant listens with both implants adjusted to user setting.<br>|
| Active Comparator: Normal Hearing Adults (NHA)<br>18+ years, Control Group | Other: Modulation Detection Threshold (MDT) and Gap Detection Tasks<br>* AIM 1 - MDT will be set at 150 Hz. Testing will be conducted in soundfield in a sound booth at 60 dB Sound Pressure Level (SPL) while the participant listens with both implants adjusted to user setting.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in loudness growth in Cochlear Implant participants | Power functions will be fit for each of the loudness growth curves. Data will be analyzed using a mixed-design ANOVA with the two groups as the between-subjects factor and electrode and rate as within-subject factors. | Baseline Visit (Day 1) , Visit week 10 | 
| Change in temporal resolution in Cochlear implant participants | A mixed-effect ANOVA will be conducted to determine if there is an effect of age group (children vs adults) and hearing condition (CI vs NH) for both modulation detection and gap detection tasks. Post-hoc two-sample t-tests will compare differences between NH and CI children as well as NH and CI adults. Post-hoc paired t-tests will compare differences between adults and children for both the NH and the CI populations. | Baseline Visit (Day 1) , Visit week 10 | 
| Change in spectral resolution in Cochlear implant participants | A one-way ANOVA will be used to calculate the differences between the four groups. If significant, post-hoc t-tests will be performed using Rom's modified Bonferroni Type I error correction. | Baseline Visit (Day 1) , Visit week 10 | 
| Difference in performance between the reduced channel map and the full map | A mixed-design ANOVA will be conducted for each of the tests with subject population as the between-subjects factor and sound coding strategy as the within-subjects factor | Baseline Visit (Day 1) , Visit week 10 |