Electric Pace-pitched Hearing Achieves Natural Tonotopy

Study Overview
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Brief Summary
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In search of the best possible outcome for the severe hearing impaired who have regained the ability to hear by means of a cochlear implant (CI), electrical stimulation and the information it carries should match as closely as possible to what the human brain naturally has evolved to cope with and learned to process instead of relying on plasticity to adapt to an induced mismatch. At the moment, however, CI's are fitted with a 'one size fits all' principle. This is known to cause a mismatch between the frequencies presented by the CI electrode array and the frequencies represented at the corresponding natural acoustic location in an individual cochlea. In this study it is hypothesized that an individual imaged based fitting that pursues natural hearing alignment and is implemented from the start of the rehabilitation process, will improve the individual outcomes of electric hearing. The natural fitting strategy is thought to give rise to a steeper learning curve, result in a better performance in challenging listening situations, improve sound quality, complement better with residual acoustic hearing in the contralateral ear and win the preference of CI-recipients.

Official Title
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Electric Pace-pitched Hearing Achieves Natural Tonotopy

Conditions
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Deafness

Intervention / Treatment
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* Device: Imaged based fitting


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Adult (18y or older) and meeting the conventional Dutch CI criteria; Proficient speaker of Dutch language; Post-lingual onset of profound deafness (> 4 years of age); Subject receives an Advanced Bionics implant with Midscala electrode and an Advanced Bionics sound processor; Prepared to use study specific hearing aid (Phonak) for the duration of the study; Rehabilitation at MUMC+ for the first year after surgery regarding CI as well as HA; Active participation in trial related procedures such as daily randomization and regular testing. Exclusion Criteria: Physical or non-physical contraindications for MRI or CT imaging; Additional disabilities that may prevent active participation and testing as per protocol. If there are indications that the mental abilities to comply with the study procedures are insufficient, additional screening will be performed with the Mini-Mental State Examination. Patients will be excluded from the study when the resulting score is lower than 24; Cochlear or neural abnormalities that could affect outcome measures and/or compromise the placement of the electrode as assessed by the CI surgeon; Active participation in another prospective clinical trial; Pregnancy at time of imaging; Requirement for electric-acoustic activation prior to the first year follow-up; Having received a cochlear implant earlier (e.g. explantation or bilateral implantation).

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Imaged based fitting<br>Mapping of the electrical input of the cochlear implant will be based on an individualized natural frequency alignment as estimated with imaging methods. | Device: Imaged based fitting<br>* Mapping of the electrical input of the cochlear implant will be based on an individualized natural frequency alignment as estimated with imaging methods.<br>|
| No Intervention: Clinical routine<br>Mapping of the electrical input of the cochlear implant will be based on a one-size-fits-all, as is part of clinical routine. | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Speech understanding in quiet with cochlear implant | Speech understanding with CI in quiet measured with the Dutch Consonant Nucleus Consonant (CNC) test. | During the first 12 months of CI rehabilitation | 
| Speech understanding in quiet with cochlear implant | Speech understanding with CI in quiet will be measured with the Dutch Matrix sentence test. | During the first 12 months of CI rehabilitation | 
| Speech understanding in noise with cochlear implant | Speech understanding with CI in noise will be measured with the Dutch Matrix sentence test. | During the first 12 months of CI rehabilitation | 
| Patient preference | At every fitting session, patients will be asked to rate their satisfaction with either the control or experimental program on a 10-point Visual Analog Sscale (1 dissatisfied - 10 very satisfied). | During the first 12 months of CI rehabilitation | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Speech understanding with hearing aid | Speech understanding with hearing aid will be measured with the Dutch Consonant Nucleus Consonant (CNC) test. | During the first 12 months of CI rehabilitation | 
| Speech understanding with hearing aid | Speech understanding with hearing aid will be measured with the Dutch Matrix sentence test. | During the first 12 months of CI rehabilitation | 
| Spatial masking | The Spatial Speech Perception In Noise (SSPIN) test will be used to determine the head shadow and squelch effect [74]. | During the first 12 months of CI rehabilitation | 
| Listening effort | In a listening effort test subjects are asked to rate the effort it takes to listen to speech fragments in noise.The listening effort test is based on subjective ratings for the ease or difficulty involved in listening to speech in the presence of varying amounts of noise. Speech and noise are presented from the same loudspeaker in front of the subject. Three relevant signal-to noise ratios will be tested repeatedly (5 times) and the mean effort level will be calculated. Rating is performed using a vertical scale with 13 discrete points (seven named categories interspersed with an empty category) ranging from no effort (Score 0) to extreme effort (Score 12). | During the first 12 months of CI rehabilitation | 
| Spectral resolution (SMRT test) | The ability to spectrally resolve frequency information is known to be related to speech understanding performance (in noise). Frequency selectivity will be monitored to test the ability of the patient to filter out one stimulus from the others on the basis of frequency. This will be done with the Spectral-temporally Modulated Ripple Test (SMRT). | During the first 12 months of CI rehabilitation | 
| Loudness scaling (ACALOS test) | To estimate the course of loudness percept between minimal audible level and maximum comfortable level, a procedure is used that automatically adjusts the presentation levels to the subject's individual auditory dynamic range without employing any pre-measurement. The procedure uses repeated measurements and presents levels in randomized order. It has been named ACALOS (Adaptive Categorical LOudness Scaling). Results will provide information about the difference in loudness percept between CI and HA and will give input for optimizing the fitting of these hearing devices across the dynamic range. | During the first 12 months of CI rehabilitation | 
| Telemetric data | By measuring Evoked Compound Action Potential (ECAP), telemetric data on the function of the implant and the response of the auditory nerve will be collected. | During the first 12 months of CI rehabilitation | 
| Quality of life in relation to hearing ability. | Measured with the Speech-Spatial-Qualities (SSQ) questionnaire. A short form of the SSQ (SSQ-12) will be used. The SSQ is designed for use typically as a complement to behavioural or experimental measures of hearing ability and consists of questions on the following domains: speech hearing, spatial hearing, qualities of hearing, and listening effort. Participants will be asked to answer 12 questions on a 10-point Visual Analogue Scale with different units. | During the first 12 months of CI rehabilitation | 
| Overall wellbeing | Measured with the ICEpop CAPability measure for adults (ICECAP-A) | During the first 12 months of CI rehabilitation | 
| Overall Quality of life | Measured with the Health Utility Index Mark 3 (HUI-3) | During the first 12 months of CI rehabilitation |