Unilateral DeafnessNCT05379231

Evaluation of BiCROS Fitting Benefits

A study testing Hearing aid fitting in people with Unilateral Deafness, run by Sonova AG at 2 sites in Canada.

Completed

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

Trial summary

22 candidates for BiCROS hearing aids will be recruited and fitted with a hearing aid and a CROS device. Following a real-world trial, each participant will be tested on a range of outcome measures including speech recognition in noise, ratings of listening effort, and ratings of preference. Read more about this study

Who is it for?: Ages 18 to 99 yearsHealthy volunteers can take part
Conditions the study is for: Unilateral Deafness
What is being tested?: Hearing aid fitting
Type of treatment: Medical device
Could I receive a placebo?: No, everyone receives an active treatment
How many people: 22 participants
Where: 2 sitesCanada
Study dates: 11 Jul 2022to 21 Mar 2023
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 to 99 years
All sexes
Healthy volunteers accepted
Adult, Older adult

Who may be able to join

unaidable hearing loss in worse ear (>N6)
aidable hearing loss (N3 to N5) on the other ear
fluent English speaker

Who cannot join

aidable hearing loss in both ears

Trial locations and contacts

2 sites in 1 country.

Canada2 sites

National Centre for Audiology
London, Ontario, N6G 1H1
Sonova Innovation Centre Toronto
Mississauga, Ontario, L5L1J3

Other trials in Canada

About this study

Official title: Evaluate the Benefit of a BiCROS Hearing Aid Fitting

Read the detailed description

Unilateral Hearing Loss (UHL) can be defined as any degree of permanent hearing loss on one ear with normal hearing in the opposite ear. Unilateral hearing loss can be debilitating associated with audiological, psychosocial and educational challenges. Audiological challenges include the reduced ability to localize sounds, reduced awareness on the unaidable side and difficulties hearing in noise or at a distance.

One solution for unaidable UHL is Contralateral Routing of Signals (CROS) and Bilateral Contralateral routing of signals (BiCROS) using a so-called CROS transmitter together with a hearing aid.

The rationale for this clinical investigation is to collect clinical data with a rechargeable CROS transmitter to evaluate the benefits of a BiCROS fitting compared to the alternative treatment option, the monaural hearing aid fitting, and to no treatment in noisy listening situations.

Hearing tests, ear impressions and hearing aid fitting visits are mainly conducted at the National Centre for Audiology in London, Ontario. Those visits are available at the Sonova Innovation Centre Toronto in Mississauga, Ontario, upon request. Outcome measurements are only conducted at the National Centre for Audiology in London, Ontario.

Conditions: Unilateral Deafness
Being tested: Hearing aid fitting
Medical subject headings: Hearing Loss, Unilateral

What participants receive

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

Hearing aid fittingDevice
A participant will wear a hearing aid with and without a CROS device on the unaidable ear.

Study groups in NCT05379231
Study group	Role	What they receive
BiCROS fitting with beamformer	Experimental	Each participant will be fitted with the experimental CROS device on the unaidable ear and with a compatible hearing aid on the other ear. A beamformer (directional microphone) will be enabled during this measurement. Although each ear receives a different device configuration depending on the condition, the participant is assigned as a whole, and assignment is not by ears. Receives: Device: Hearing aid fitting
BiCROS fitting omni	Experimental	Each participant will be fitted with the experimental CROS device on the unaidable ear and with a compatible hearing aid on the other ear. The microphones will be omnidirectional. Although each ear receives a different device configuration depending on the condition, the participant is assigned as a whole, and assignment is not by ears. Receives: Device: Hearing aid fitting
Monaural hearing aid fitting with beamformer	Active comparator	Each participant will be fitted with a hearing aid on the better hearing ear and no device on the unaidable ear. A beamformer (directional microphone) will be enabled during the measurement. Although each ear receives a different device configuration depending on the condition, the participant is assigned as a whole, and assignment is not by ears. Receives: Device: Hearing aid fitting
Monaural hearing aid fitting omni	Active comparator	Each participant will be fitted with a hearing aid on the better hearing ear and no device on the unaidable ear. The microphone will be omnidirectional. Although each ear receives a different device configuration depending on the condition, the participant is assigned as a whole, and assignment is not by ears. Receives: Device: Hearing aid fitting
Unaided condition	No intervention	No intervention, the participants are not fitted with a CROS device and/or hearing aid.

What is being measured

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

Speech Intelligibility in Noise Measured With US Matrix Test (Noise From a Defined Loudspeaker)
Measuring the Signal to Noise Ratio change in decibels (dB) for speech from the front loudspeaker and noise from the better ear's side with the US matrix Test. Results of the speech test will be the SRT (speech recognition threshold) in dB SNR (signal to noise ratio).
The target speaker will be presented from 0° azimuth and is adaptive (start level at 65dB (A)).
The noise will be presented on the better ear at an azimuth of 90° or 270° (depending on the site of the better ear), at a level of 65 dB (A).
Measured: At the appointment following the 4 weeks home trial each participant went on wearing the BiCROS fitting

Secondary outcomes (6)

Speech Intelligibility in Noise Measured With US Matrix Test (Diffuse Noise)
Measuring the Signal to Noise Ratio change in decibels (dB) for speech from the front loudspeaker in surrounding noise with the US Matrix Test. Results of the speech test will be the SRT (speech recognition threshold) in dB SNR (signal to noise ratio).
The target speaker will be presented from 0° azimuth and is adaptive (start level at 65dB (A).
The noise will be presented from a circle of 8 surrounding speakers from 45° to 315° at a level of 65 dB (A) with the participant seated in the centre of the circle.
Measured: At the appointment following the 4 weeks home trial each participant went on wearing the BiCROS fitting
Reports of Subjective Quality of Hearing as Assessed by the SSQ
Measured after home trial with the Speech, Spatial and Qualities of Hearing Scale-Benefit (Gatehouse, 2004). The scale ranges from -5 to 5, where negative values indicate that the condition under test is worse than the comparator, 0 indicates no change, and positive values indicate a benefit of the condition under test compared to the comparator.
Measured: At the appointment following the 4 weeks home trial each participant went on wearing the BiCROS fitting
Reports of Subjective Quality of Hearing as Assessed by the Bern Benefit Questionnaires
Measured after home trial with the Bern Benefit in Single-Sided Deafness Questionnaire (Komps et al, 2011). The scale ranges from -5 to 5, where negative values indicate that the condition under test is better wihtout the hearing aid, 0 indicates no change, and positive values indicate a benefit with the hearing aid.
Measured: At the appointment following the 4 weeks home trial each participant went on wearing the BiCROS fitting
Sound Quality Ratings for Total Impression and Clarity Using Gabriellson et al (1990) Ratings Scales
Ratings of speech in noise presented via loudspeakers using Gabriellson et al (1990) Ratings Scales. Scales include Clarity and Total Impression, and range from 1 to 10. The higher the rating, the better the Clarity and Total Impression.
Measured: At the appointment following the 4 weeks home trial each participant went on wearing the BiCROS fitting
Subjective Preference of Hearing Aid Condition
3 alternative forced choice (A, B, no preference or ABX) paradigm with three repetitions for speech in noise presented via loudsepakers
Measured: At the appointment following the 4 weeks home trial each participant went on wearing the BiCROS fitting
Listening Effort in Noise Using 7 Point Scale (Holmes et. al., 2018)
Measuring listening effort for speech in multi-talker babble presented via loudspeaker. The scale ranges from 1 to 7, and a higher rating indicates less listening effort.
Measured: At the appointment following the 4 weeks home trial each participant went on wearing the BiCROS fitting

Timeline

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

11 Jul 202221 Mar 2023

First posted18 May 2022
Study start11 Jul 2022
Primary completion21 Mar 2023
Study completion21 Mar 2023

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 Unilateral DeafnessStudies 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: Other
Allocation: Randomised
Intervention model: Crossover
Model description: All participants were wearing the BiCROS fitting during home trial, and tested in-lab with all conditions, randomized and counterbalanced (BiCROS fitting, monaural fitting, unaided).
Masking: None (open label)
Enrolment: 22 participants (actual)

IDs, dates and publications

ClinicalTrials.gov ID: NCT05379231
Sponsor's protocol ID: 461
Status last verified: Mar 2023
First submitted: 8 Apr 2022
Last updated: 11 Jun 2025
Results posted: Yes, on ClinicalTrials.gov
Data monitoring committee: No
FDA-regulated drug: No
FDA-regulated device: No
Individual data sharing: No

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

RecruitingObservational study
Rare Disease Patient Registry & Natural History Study - Coordination of Rare Diseases at Sanford
Rare Disorders, Undiagnosed Disorders
Recruiting
Evaluation of Cochlear Implantation in Unilateral or Asymmetric Hearing Loss in Children.
Unilateral Hearing Loss, Asymmetric Hearing Loss
Active, not recruiting
Single-Sided Deafness and Asymmetric Hearing Loss
Hearing Loss, Unilateral, Hearing Loss, Sensorineural
Recruiting
Towards Implementation of Universal Newborn Hearing Screening in Kenya
Hearing Loss, Bilateral or Unilateral, Otitis Media With Effusion in Children
Active, not recruiting
Investigation to Evaluate the Safety and Effectiveness of Cochlear Implantation in Children and Adults With Unilateral Hearing Loss/Single-sided Deafness
Hearing Loss, Unilateral, Deafness, Unilateral

All Unilateral Deafness trials

Study at a glance

From the registry record, last updated by the sponsor on 11 Jun 2025. Recruitment status is as the sponsor reported it: confirm with the study team.

Official title: Evaluate the Benefit of a BiCROS Hearing Aid Fitting
ClinicalTrials.gov ID: NCT05379231
Acronym / sponsor ID: 461
Conditions: Unilateral Deafness
Study type: Interventional
Recruitment status: Completed
Enrolment: 22 participants (actual)
Lead sponsor: Sonova AGIndustry (pharma, biotech, devices)
Collaborators: Western University, Canada
Study start: 11 Jul 2022 (actual)
Primary completion: 21 Mar 2023 (actual)
Study completion: 21 Mar 2023 (actual)
First posted: 18 May 2022 (actual)
Results: Posted 11 Jun 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

One solution for unaidable UHL is Contralateral Routing of Signals (CROS) and Bilateral Contralateral routing of signals (BiCROS) using a so-called CROS transmitter together with a hearing aid.

Study design

Primary purpose: Other
Allocation: Randomised
Intervention model: Crossover
Masking: None (open label)
Number of arms: 5
Model description: All participants were wearing the BiCROS fitting during home trial, and tested in-lab with all conditions, randomized and counterbalanced (BiCROS fitting, monaural fitting, unaided).

Arm	Type	Receives
BiCROS fitting with beamformer	Experimental	Device: Hearing aid fittingEach participant will be fitted with the experimental CROS device on the unaidable ear and with a compatible hearing aid on the other ear. A beamformer (directional microphone) will be enabled during this measurement. Although each ear receives a different device configuration depending on the condition, the participant is assigned as a whole, and assignment is not by ears.
BiCROS fitting omni	Experimental	Device: Hearing aid fittingEach participant will be fitted with the experimental CROS device on the unaidable ear and with a compatible hearing aid on the other ear. The microphones will be omnidirectional. Although each ear receives a different device configuration depending on the condition, the participant is assigned as a whole, and assignment is not by ears.
Monaural hearing aid fitting with beamformer	Active comparator	Device: Hearing aid fittingEach participant will be fitted with a hearing aid on the better hearing ear and no device on the unaidable ear. A beamformer (directional microphone) will be enabled during the measurement. Although each ear receives a different device configuration depending on the condition, the participant is assigned as a whole, and assignment is not by ears.
Monaural hearing aid fitting omni	Active comparator	Device: Hearing aid fittingEach participant will be fitted with a hearing aid on the better hearing ear and no device on the unaidable ear. The microphone will be omnidirectional. Although each ear receives a different device configuration depending on the condition, the participant is assigned as a whole, and assignment is not by ears.
Unaided condition	No intervention	–No intervention, the participants are not fitted with a CROS device and/or hearing aid.

Who may qualify

Ages: 18 to 99 years
Sex: All
Healthy volunteers: Accepted
Age groups: Adult, Older adult

Key inclusion criteria (3 listed)

unaidable hearing loss in worse ear (>N6)
aidable hearing loss (N3 to N5) on the other ear
fluent English speaker

Key exclusion criteria (1 listed)

aidable hearing loss in both ears

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
Hearing aid fittingA participant will wear a hearing aid with and without a CROS device on the unaidable ear.	Device	BiCROS fitting omni, BiCROS fitting with beamformer, Monaural hearing aid fitting omni, Monaural hearing aid fitting with beamformer

Primary outcome

Speech Intelligibility in Noise Measured With US Matrix Test (Noise From a Defined Loudspeaker)
Time frame: At the appointment following the 4 weeks home trial each participant went on wearing the BiCROS fitting
Measuring the Signal to Noise Ratio change in decibels (dB) for speech from the front loudspeaker and noise from the better ear's side with the US matrix Test. Results of the speech test will be the SRT (speech recognition threshold) in dB SNR (signal to noise ratio). The target speaker will be presented from 0° azimuth and is adaptive (start level at 65dB (A)). The noise will be presented on the better ear at an azimuth of 90° or 270° (depending on the site of the better ear), at a level of 65 dB (A).

6 secondary outcomes

Speech Intelligibility in Noise Measured With US Matrix Test (Diffuse Noise)
Time frame: At the appointment following the 4 weeks home trial each participant went on wearing the BiCROS fitting
Reports of Subjective Quality of Hearing as Assessed by the SSQ
Time frame: At the appointment following the 4 weeks home trial each participant went on wearing the BiCROS fitting
Reports of Subjective Quality of Hearing as Assessed by the Bern Benefit Questionnaires
Time frame: At the appointment following the 4 weeks home trial each participant went on wearing the BiCROS fitting
Sound Quality Ratings for Total Impression and Clarity Using Gabriellson et al (1990) Ratings Scales
Time frame: At the appointment following the 4 weeks home trial each participant went on wearing the BiCROS fitting
Subjective Preference of Hearing Aid Condition
Time frame: At the appointment following the 4 weeks home trial each participant went on wearing the BiCROS fitting
Listening Effort in Noise Using 7 Point Scale (Holmes et. al., 2018)
Time frame: At the appointment following the 4 weeks home trial each participant went on wearing the BiCROS fitting

Results and safety

Results posted to the registry on 11 Jun 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
Complete Sample	20	18

Primary outcome: Speech Intelligibility in Noise Measured With US Matrix Test (Noise From a Defined Loudspeaker)

Time frame: At the appointment following the 4 weeks home trial each participant went on wearing the BiCROS fitting. Mean (Standard Deviation). Unit: dBSRT

Measure	BiCROS With Beamformer n = 18	BiCROS Omni n = 18	Monaural With Beamformer n = 18	Monaural Omni n = 18	Unaided n = 18
Value	-8.8 (3.4)	-3.7 (2.9)	-9.2 (2.7)	-2.8 (2.5)	-0.1 (6.8)

Population analysed: Although each ear receives a different device configuration depending on the condition (except for the unaided condition), the participant is assigned as a whole, and assignment is not by ears.

6 secondary outcomes are reported in the full results.

Adverse events

Time frame: From the first appointment the participant was enrolled and assessed, until the last appointment that concluded the home trial and study participation. The whole duration was about 5-6 weeks per participant.. Other adverse events reported at 0% frequency or more

Group	Serious adverse events	Other adverse events	Deaths
Complete Sample	0 of 22 (0%)	2 of 22 (9.1%)	0 of 22

Loading the posted results from ClinicalTrials.gov…

Research links

Official record on ClinicalTrials.govLast updated by the sponsor 11 Jun 2025.
Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
Individual participant dataSharing planned: No

Related trials for Unilateral Deafness

RecruitingObservational study
Rare Disease Patient Registry & Natural History Study - Coordination of Rare Diseases at Sanford
Rare Disorders, Undiagnosed Disorders
Recruiting
Evaluation of Cochlear Implantation in Unilateral or Asymmetric Hearing Loss in Children.
Unilateral Hearing Loss, Asymmetric Hearing Loss
Active, not recruiting
Single-Sided Deafness and Asymmetric Hearing Loss
Hearing Loss, Unilateral, Hearing Loss, Sensorineural
Recruiting
Towards Implementation of Universal Newborn Hearing Screening in Kenya
Hearing Loss, Bilateral or Unilateral, Otitis Media With Effusion in Children
Active, not recruiting
Investigation to Evaluate the Safety and Effectiveness of Cochlear Implantation in Children and Adults With Unilateral Hearing Loss/Single-sided Deafness
Hearing Loss, Unilateral, Deafness, Unilateral

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.

Susan Scollie principal investigator

Western University, Canada

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

Questions about this trial

What is this clinical trial studying?

A study testing Hearing aid fitting in people with Unilateral Deafness, run by Sonova AG at 2 sites in Canada.

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 3 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 11 Jun 2025. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 2 sites in Canada. 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 11 Jun 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 Intelligibility in Noise Measured With US Matrix Test (Noise From a Defined Loudspeaker) (time frame: At the appointment following the 4 weeks home trial each participant went on wearing the BiCROS fitting). 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 NCT05379231.

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 11 Jun 2025.