OutcomesNCT05494632

Interaural Frequency and Loudness Mismatch in SSD CI Users

A study testing Treatment-modifications to CI speech processor program. Specifically reducing interaural frequency mismatch in experienced SSD-CI recipients., Treatment-modifications to CI speech processor program to reduced interaural frequency mismatch in newly implanted SSD-CI recipients. and Treatment-modifications to CI speech processor program to reduced interaural loudness mismatch in experienced SSD-CI recipients. in people with Outcomes, run by Washington University School of Medicine at 1 site in United States.

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Official record

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Trial summary

Interaural loudness and pitch mismatch in single-sided deaf cochlear implant (SSD-CI) recipients reduces binaural processing cues and contributes to performance outcomes, specifically speech understanding in noise and localization. Read more about this study

Who is it for?: Ages 18 years and older
Conditions the study is for: Outcomes
What is being tested?: Treatment-modifications to CI speech processor program. Specifically reducing interaural frequency mismatch in experienced SSD-CI recipients., Treatment-modifications to CI speech processor program to reduced interaural frequency mismatch in newly implanted SSD-CI recipients. and Treatment-modifications to CI speech processor program to reduced interaural loudness mismatch in experienced SSD-CI recipients.
Type of treatment: Medical device
Could I receive a placebo?: No, everyone receives an active treatment
How many people: 45 participants
Where: 1 siteUnited States
Study dates: 12 Aug 2022to 1 Aug 2025
Phase: Interventional
Are there results?: Yes, posted in the registrySummary in the doctors' view

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 years and older
All sexes
No healthy volunteers
Adult, Older adult

Who may be able to join

Participants for the proposed study will be adults with single-sided deafness. Participants will have at least 6 months experience with their cochlear implant or will be newly implanted with the cochlear implant.
Inclusion criteria for the experienced CI user group and the newly implant group are as follows:
18 years of age and older
Postlingual onset of SSD
Pure tone average (PTA) at 500, 1000, and 2000 Hz of less than or equal to 30 dB HL in the contralateral ear, known as the normal hearing ear
Implanted with or chosen to be implanted with a Nucleus cochlear implant
Full insertion of electrode array

Who cannot join

• Not meeting the inclusion criteria

Trial locations and contacts

1 site in 1 country.

United States1 site

Washington University School of Medicine
St Louis, Missouri, 63110

Other trials in United States

About this study

Official title: Effects of Interaural Frequency and Loudness Mismatch on SSD-CI Performance

Read the detailed description

Effective binaural processing depends on similar loudness growth functions at each ear. The use of interaural level differences (ILDs), perceived as loudness differences, to locate sound is critical given the inability of cochlear implant (CI) recipients to use interaural time differences (ITDs) in binaural processing. In CI recipients with single-sided deafness (SSD), perceived interaural loudness differences may not be valid indicators of interaural level differences because the CI compresses amplitude. Studies suggest better preservation of ILDs may contribute to improved localization and understanding in noise. Since SSD-CI recipients use only one device, an approach to improve their use of ILDs is to match perceived loudness at each ear.

Binaural processing is also affected when signals of equal frequency are not matched in pitch at each ear. In bilateral CI recipients, the investigators found that the greater the pitch mismatch between ears, the poorer the speech understanding in noise. The investigators want to extend this work to SSD-CI recipients. Through CI program modifications, the study aims to decrease the pitch and loudness mismatch between the CI ear and the normal hearing ear to improve binaural listening abilities, specifically speech understanding in noise and sound localization.

Conditions: Outcomes
Being tested: Treatment-modifications to CI speech processor program. Specifically reducing interaural frequency mismatch in experienced SSD-CI recipients., Treatment-modifications to CI speech processor program to reduced interaural frequency mismatch in newly implanted SSD-CI recipients., Treatment-modifications to CI speech processor program to reduced interaural loudness mismatch in experienced SSD-CI recipients.

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

Treatment-modifications to CI speech processor program. Specifically reducing interaural frequency mismatch in experienced SSD-CI recipients.Device
We will modify the CI speech processor program to reduce interaural frequency mismatch between the CI ear and the contralateral ear in experienced CI recipients with SSD.
Treatment-modifications to CI speech processor program to reduced interaural frequency mismatch in newly implanted SSD-CI recipients.Device
We will modify the CI speech processor program to reduce interaural frequency mismatch between the CI ear and the contralateral ear in newly implanted CI recipients with SSD.
Treatment-modifications to CI speech processor program to reduced interaural loudness mismatch in experienced SSD-CI recipients.Device
We will modify the CI speech processor program to reduce interaural loudness mismatch between the CI ear and the contralateral ear in experienced CI recipients with SSD.

Study groups in NCT05494632
Study group	Role	What they receive
Period 1: Study 1	Experimental	CI speech processor programming in experienced cochlear implant (CI) recipients with single sided deafness. Program changes were made to decrease the interaural frequency mismatch between the CI ear and the contralateral ear. Receives: Device: Treatment-modifications to CI speech processor program. Specifically reducing interaural frequency mismatch in experienced SSD-CI recipients.
Period 2: Study 2	Experimental	CI speech processor programming in newly implanted cochlear implant (CI) recipients with single sided deafness. Program changes were made to decrease the interaural frequency mismatch between the CI ear and the contralateral ear. Receives: Device: Treatment-modifications to CI speech processor program to reduced interaural frequency mismatch in newly implanted SSD-CI recipients.
Period 3: study 3	Experimental	CI speech processor programming in experienced cochlear implant (CI) recipients with single sided deafness. Program changes were made to decrease the interaural loudness mismatch between the CI ear and the contralateral ear. Receives: Device: Treatment-modifications to CI speech processor program to reduced interaural loudness mismatch in experienced SSD-CI recipients.

What is being measured

The primary outcome is the main question the study is designed to answer.

Speech Understanding in Noise, Measured With the R-Space Test Environment. The R-Space Test Environment Simulates Speech Understanding in a Noisy Restaurant.
Participants speech understanding was evaluated in the R-Space test environment with two speech processor programs, an everyday or default program and a modified program. The modified program was created to reduce interaural frequency or loudness mismatch between participants' CI ear and normal hearing ear. The R-Space simulates listening in a noisy restaurant, a real-world listening situation. The score is a signal-to-noise ratio that reflects 50% speech understanding in noise. Participants are surrounded by 8 loudspeakers with restaurant noise from all 8. A sentence is presented from the front loudspeaker. Participants repeat back what they hear. The noise is adjusted adaptively. For a correct response, the noise is increased; it is decreased for an incorrect response. This provides signal-to-noise ratio (SNR) for 50% speech understanding. The average score for participants with normal hearing is -5 dB SNR. A lower number represents better performance than a higher number.
Measured: Participants were tested in the R-Space twice with each speech processor program, e.g., everyday or default program and modified program. The testing was carried out within a 2-3 month time period, and after using each program for at least 6 weeks.

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

12 Aug 20221 Aug 2025

First posted10 Aug 2022
Study start12 Aug 2022
Primary completion30 Jul 2024
Study completion1 Aug 2025

Resources

Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
Other trials for OutcomesStudies of the same condition, open and under way.
More trials run by Washington University School of MedicineThe sponsor's other registered studies.
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: Treatment
Allocation: Non-randomised
Intervention model: Single group
Masking: None (open label)
Enrolment: 45 participants (actual)

IDs, dates and publications

ClinicalTrials.gov ID: NCT05494632
Sponsor's protocol ID: 202206085
Status last verified: Mar 2026
First submitted: 8 Aug 2022
Last updated: 23 Mar 2026
Results posted: Yes, on ClinicalTrials.gov
Data monitoring committee: No
FDA-regulated drug: No
FDA-regulated device: Yes

Want to know more?

The sponsor has not listed a contact. The official record may have more details.

Talk to your doctor first and take this page with you. Only the study team can confirm whether you can join.

Questions to ask the study team

What is the study trying to find out?
What would I need to do, and how often would I visit?
Could I receive a placebo instead of the treatment?
What are the possible risks and benefits for me?
Will it cost me anything? Are travel or time paid for?
Can I keep seeing my own doctor during the study?
What happens when the study ends?

See locations

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Study at a glance

From the registry record, last updated by the sponsor on 23 Mar 2026. Recruitment status is as the sponsor reported it: confirm with the study team.

Official title: Effects of Interaural Frequency and Loudness Mismatch on SSD-CI Performance
ClinicalTrials.gov ID: NCT05494632
Acronym / sponsor ID: 202206085
Conditions: Outcomes
Study type: Interventional
Recruitment status: Completed
Enrolment: 45 participants (actual)
Lead sponsor: Washington University School of MedicineUniversity, hospital or other
Collaborators: Cochlear
Study start: 12 Aug 2022 (actual)
Primary completion: 30 Jul 2024 (actual)
Study completion: 1 Aug 2025 (actual)
First posted: 10 Aug 2022 (actual)
Results: Posted 1 Jul 2025

Clinical summary

The research question as the sponsor registered it. This describes what the study plans to test, not what it found.

Detailed description

Study design

Primary purpose: Treatment
Allocation: Non-randomised
Intervention model: Single group
Masking: None (open label)
Number of arms: 3

Arm	Type	Receives
Period 1: Study 1	Experimental	Device: Treatment-modifications to CI speech processor program. Specifically reducing interaural frequency mismatch in experienced SSD-CI recipients.CI speech processor programming in experienced cochlear implant (CI) recipients with single sided deafness. Program changes were made to decrease the interaural frequency mismatch between the CI ear and the contralateral ear.
Period 2: Study 2	Experimental	Device: Treatment-modifications to CI speech processor program to reduced interaural frequency mismatch in newly implanted SSD-CI recipients.CI speech processor programming in newly implanted cochlear implant (CI) recipients with single sided deafness. Program changes were made to decrease the interaural frequency mismatch between the CI ear and the contralateral ear.
Period 3: study 3	Experimental	Device: Treatment-modifications to CI speech processor program to reduced interaural loudness mismatch in experienced SSD-CI recipients.CI speech processor programming in experienced cochlear implant (CI) recipients with single sided deafness. Program changes were made to decrease the interaural loudness mismatch between the CI ear and the contralateral ear.

Who may qualify

Ages: 18 years and older
Sex: All
Healthy volunteers: Not accepted
Age groups: Adult, Older adult

Key inclusion criteria (7 listed)

Participants for the proposed study will be adults with single-sided deafness. Participants will have at least 6 months experience with their cochlear implant or will be newly implanted with the cochlear implant.
Inclusion criteria for the experienced CI user group and the newly implant group are as follows:
18 years of age and older
Postlingual onset of SSD
Pure tone average (PTA) at 500, 1000, and 2000 Hz of less than or equal to 30 dB HL in the contralateral ear, known as the normal hearing ear

Key exclusion criteria (1 listed)

• Not meeting the inclusion criteria

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
Treatment-modifications to CI speech processor program. Specifically reducing interaural frequency mismatch in experienced SSD-CI recipients.We will modify the CI speech processor program to reduce interaural frequency mismatch between the CI ear and the contralateral ear in experienced CI recipients with SSD.	Device	Period 1: Study 1
Treatment-modifications to CI speech processor program to reduced interaural frequency mismatch in newly implanted SSD-CI recipients.We will modify the CI speech processor program to reduce interaural frequency mismatch between the CI ear and the contralateral ear in newly implanted CI recipients with SSD.	Device	Period 2: Study 2
Treatment-modifications to CI speech processor program to reduced interaural loudness mismatch in experienced SSD-CI recipients.We will modify the CI speech processor program to reduce interaural loudness mismatch between the CI ear and the contralateral ear in experienced CI recipients with SSD.	Device	Period 3: study 3

Primary outcome

Speech Understanding in Noise, Measured With the R-Space Test Environment. The R-Space Test Environment Simulates Speech Understanding in a Noisy Restaurant.
Time frame: Participants were tested in the R-Space twice with each speech processor program, e.g., everyday or default program and modified program. The testing was carried out within a 2-3 month time period, and after using each program for at least 6 weeks.
Participants speech understanding was evaluated in the R-Space test environment with two speech processor programs, an everyday or default program and a modified program. The modified program was created to reduce interaural frequency or loudness mismatch between participants' CI ear and normal hearing ear. The R-Space simulates listening in a noisy restaurant, a real-world listening situation. The score is a signal-to-noise ratio that reflects 50% speech understanding in noise. Participants are surrounded by 8 loudspeakers with restaurant noise from all 8. A sentence is presented from the front loudspeaker. Participants repeat back what they hear. The noise is adjusted adaptively. For a correct response, the noise is increased; it is decreased for an incorrect response. This provides signal-to-noise ratio (SNR) for 50% speech understanding. The average score for participants with normal hearing is -5 dB SNR. A lower number represents better performance than a higher number.

Results and safety

Results posted to the registry on 1 Jul 2025, as reported by the sponsor. Figures are copied from the record, not re-analysed. Full results on ClinicalTrials.gov.

Participant flow

Group	Started	Completed
Period 1: Study 1	20	20
Period 2: Study 2 Group Starting With Default FAT	5	5
Period 2: Study 2 Group Starting With Modified FAT	5	5
Period 3: Study 3	15	15

Primary outcome: Speech Understanding in Noise, Measured With the R-Space Test Environment. The R-Space Test Environment Simulates Speech Understanding in a Noisy Restaurant.

Time frame: Participants were tested in the R-Space twice with each speech processor program, e.g., everyday or default program and modified program. The testing was carried out within a 2-3 month time period, and after using each program for at least 6 weeks.. Median (Standard Deviation). Unit: signal-noise-ratio in decibels (dB)

Measure	Period 1: Study 1 n = 20	Period 2: Study 2 Group Starting With Default FAT n = 5	Period 2: Study 2 Group Starting With Modified FAT n = 5	Period 3: Study 3 n = 15
Everyday FAT (study 1), Default FAT (study 2), Everyday loudness program (study 3)	-3.0 (1.6)	-1.9 (1.9)	-4.0 (0.7)	-2.9 (1.1)
Modified FAT (study 1 and 2), Modified loudness program (study 3)	-3.6 (1.1)	-2.9 (2.5)	-3.6 (1.0)	-4.1 (1.0)

Period 1: Study 1: Median Difference (Net): 1.0, p <0.001, Wilcoxon (Mann-Whitney)

Population analysed: 20 experienced SSD-CI participants were tested in the R-Space with their everyday use FAT and with the modified FAT (Study 1). Ten newly implanted SSD-CI participated in Study 2. The newly implanted group were tested in the R-Space with the manufacturer's default FAT and with a modified FAT. Fifteen experienced SSD-CI users were tested in the R-SPACE with their everyday program and with a modified loudness program (Study 3). Testing was done twice with each FAT or loudness program.

Adverse events

Time frame: Adverse events were collected over a period of approximately 16 weeks for each group.. Other adverse events reported at 0% frequency or more

Group	Serious adverse events	Other adverse events	Deaths
Period 1: Study 1	0 of 20 (0%)	0 of 20 (0%)	0 of 20
Period 2: Study 2	0 of 10 (0%)	0 of 10 (0%)	0 of 10
Period 3: Study 3	0 of 15 (0%)	0 of 15 (0%)	0 of 15

Limitations and caveats (from the sponsor): One of the limitations was the small number of SSD participants in the trial.

Loading the posted results from ClinicalTrials.gov…

Research links

Official record on ClinicalTrials.govLast updated by the sponsor 23 Mar 2026.
Posted resultsParticipant flow, baseline, all outcome measures and adverse events.

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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.

Jill B Firszt, PhD principal investigator

Washington University School of Medicine

1 site in 1 country: see every site and its status.

Questions about this trial

What is this clinical trial studying?

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 7 inclusion and 1 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 23 Mar 2026. 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 United States. 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?

Yes. Results are posted in the registry (first posted 1 Jul 2025). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.

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?

Speech Understanding in Noise, Measured With the R-Space Test Environment. The R-Space Test Environment Simulates Speech Understanding in a Noisy Restaurant. (time frame: Participants were tested in the R-Space twice with each speech processor program, e.g., everyday or default program and modified program. The testing was carried out within a 2-3 month time period, and after using each program for at least 6 weeks.). 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 NCT05494632.

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 23 Mar 2026.