Improved Speech Recognition Performance in Noise by Encoding Binaural Spatial Cues to the Cochlea Implant User

Study Overview
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Brief Summary
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The aim of the study is to evaluate the interaural time difference (ITD) benefit in patient with bilateral cochlear implants and to assess speech performance in noisy conditions compared to normal hearing listeners. Half of participants are bilateral cochlear implants users, while the other are normal hearing listeners.

Detailed Description
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Listening in noisy environments is part of everyday life, it is based on binaural phenomena such as spatial localization Bilateral cochlear implants certainly restore a part of binaurality

Official Title
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Improved Speech Recognition Performance in Noise by Encoding Binaural Spatial Cues to the Cochlea Implant User

Conditions
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Hearing Loss, Cochlear

Intervention / Treatment
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* Other: S0N0
* Other: S0N500
* Other: S-500N500
* Other: S0N1000
* Other: S0Nuncorr


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Fluent in local language Normal hearing listener: pure tone threshold > 25dB from 125Hz to 12kHz Cochlear implant recipient bilaterally implanted 6 months at least, the second implant should be implanted 6 months at least before participant inclusion Digisonic SP® cochlear implants user Exclusion Criteria: binaural sensitivity threshold < 1000µs

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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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: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: bilateral cochlear implant recipients<br> | Other: S0N0<br>* (no ITD)<br>Other: S0N500<br>* (ITD +500µs on noise)<br>Other: S-500N500<br>* (ITD -500µs on signal and +500 µs on noise)<br>Other: S0N1000<br>* (ITD + 1000 µs on noise)<br>Other: S0Nuncorr<br>* (no ITD cue, with uncorrelated stimulation frame)<br>|
| Active Comparator: normal hearing listners<br> | Other: S0N0<br>* (no ITD)<br>Other: S0N500<br>* (ITD +500µs on noise)<br>Other: S-500N500<br>* (ITD -500µs on signal and +500 µs on noise)<br>Other: S0N1000<br>* (ITD + 1000 µs on noise)<br>Other: S0Nuncorr<br>* (no ITD cue, with uncorrelated stimulation frame)<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| speech reception threshold (SRT) in bilateral cochlear implant user with ITD cue | SRT is used as an outcome measure to quantify the acuity for speech perception in noise with Interaural Time Difference between the two ears. Signal recognition in a background noise is assessed the following conditions S0N0, S0N500, S0N1000, S-500N500 et S0Nuncorr. The noise level is constant at 65 dB SPL, the signal level is modified in the adaptive procedure in order to converge towards a score of 50% of correct response. | day 0 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| speech reception threshold (SRT) in bilateral cochlear implant user without ITD cue and in normal hearing listeners | SRT is used as an outcome measure to quantify the acuity for speech perception in noise without Interaural Time Difference between the two ears. | day 0 | 
| ITD sensitivity in bilateral cochlear implant user | Speech signal and noise are presented at 65dB SPL. Participant adjust the Interaural Time Difference between the speech signal and noise between -1000 and +1000µs. Participant moves the cursor on the interface until he/she hear a difference in sound. | day 0 | 
| Preferred jitter in bilateral cochlear implant user | Speech signal and noise are presented at 65dB SPL. Participant adjust the jitter of the train pulse timing from 0 to +1000µs to improve the Interaural Time Difference. | day 0 | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Iteraural Time Difference