A Comparison of a New Acoustic Feedback Canceller in Hearing Aids With the Current System

Study Overview
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Brief Summary
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The Purpose of the study is to show that the performance of the new feedback cancellation system is better than the feedback system used in the currently marketed hearing aids. Speech understanding should not be negatively affected by the new system, ad there should be no consequential artifacts or unwanted noises caused by the new system.

Detailed Description
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The amplification of sounds with a hearing aid is the most common treatment for hearing loss. Benefits of amplification and accessories used with it outweigh any risks in mild to profound hearing-impaired subjects. Hearing aids provide a benefit for people with only a mild sensorineural hearing loss. However, often people are counselled to wait to purchase hearing aids until their hearing loss becomes more significant. The benefits are obtainable for both unilateral and bilateral fittings and are both short term and durable on long term. Acoustic feedback is a critical problem to all hearing aids. The acoustic coupling between the hearing aid receiver and the microphone occurs when an endless loop is formed so that the microphone is re-amplifying sound from its own receiver. The higher the amplification of the system, the more unstable it becomes and the more likely an acoustic feedback will occur. When this happens the hearing aid user and those around them hear a loud whistling noise. A common method used to combat this problem is feedback cancellation, more specifically adaptive feedback cancellation. The goal of feedback cancellation is to quickly identify feedback path changes and make adjustments to preserve the stability of the system while maintaining a high sound quality and still providing a high stable gain compared to the gain achieved without an active feedback reduction. For this study, the Sponsor will carry out testing with participants who have hearing loss to validate the performance of the new feedback cancelling algorithm. Studies have investigated the advantages and disadvantages of different feedback cancellation techniques. However, it is accepted by professionals that having a feedback system is better than not using feedback cancellation. The Sponsor has used an adaptive feedback cancellation algorithm since 2010. For the current study the new adaptive algorithm will be compared to the current algorithm implemented in the hearing aids that are certified by the European Conformity and sold on the market. The aim is to determine if less feedback is experienced using the new system in comparison to the old system.

Official Title
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A Comparative, Controlled Clinical Investigation of a New Acoustic Feedback Cancellation Strategy in Comparison With the Currently Marketed System

Conditions
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Hearing Loss

Intervention / Treatment
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* Device: Hearing Aid Mermaid Current
* Device: Hearing Aid Mermaid New
* Device: Power Hearing Aid Current
* Device: Power Hearing Aid New


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: All classifications of hearing loss (sensorineural, conductive, mixed) Conductive and mixed hearing loss must be approved for amplification by a physician All shapes of hearing loss (flat, sloping, reverse slope, notch) Severity ranging from mild to profound German speaking Ability and willingness to sign the consent form Exclusion Criteria: Contraindications for amplification Active ear disease New hearing aid users Inability to follow the procedures Reduced mobility that makes then unable to attend study Appointments Uncooperative so that it's not possible to get a valid audiogram A strongly reduced dexterity Central hearing disorder Sponsor employees Family members of Sponsor employees

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: Treatment
Allocation: Randomized
Intervention Model: Crossover Assignment
Interventional Model Description: The participants will wear hearing aids with the current feedback system and the new feedback system each for 10 +/- 5 days. Some will wear the current hearing aids first and some will wear the new Hearing aids first.
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Moderate Hearing loss current Mermaid first, then new<br>Participants were randomized to wear the current Mermaid hearing aid that uses the current feedback cancellation first for 10 days. Then they wore the new Mermaid Hearing aid for another 10 days. | Device: Hearing Aid Mermaid Current<br>* The current hearing aid used to treat hearing loss.<br>Device: Hearing Aid Mermaid New<br>* The new hearing aid used to treat hearing loss with an upgraded feedback cancellation system.<br>|
| Active Comparator: Moderate Hearing loss new Mermaid first, then current<br>Participants were randomized to wear the new Mermaid hearing aid that uses the new feedback cancellation first for 10 days. Then they wore the current Mermaid Hearing aid for another 10 days. | Device: Hearing Aid Mermaid Current<br>* The current hearing aid used to treat hearing loss.<br>Device: Hearing Aid Mermaid New<br>* The new hearing aid used to treat hearing loss with an upgraded feedback cancellation system.<br>|
| Active Comparator: Severe hearing loss current Power first, then new<br>Participants were randomized to wear the current power hearing aid that uses the current feedback cancellation first for 10 days. Then they wore the new power Hearing aid for another 10 days. | Device: Power Hearing Aid Current<br>* The current power hearing aid used to treat strong hearing loss.<br>Device: Power Hearing Aid New<br>* The new power hearing aid used to treat strong hearing loss with an upgraded feedback cancellation system.<br>|
| Active Comparator: Severe hearing loss new Power first, then current<br>Participants were randomized to wear the new power hearing aid that uses the new feedback cancellation first for 10 days. Then they wore the current power Hearing aid for another 10 days. | Device: Power Hearing Aid Current<br>* The current power hearing aid used to treat strong hearing loss.<br>Device: Power Hearing Aid New<br>* The new power hearing aid used to treat strong hearing loss with an upgraded feedback cancellation system.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in Live Feedback Test Scores From Day 10 to Day 20 | In the lab, subjects will have the hearing aid placed in their ear. They will rate on a visual analogue scale whether feedback occurs and if so, how much annoyance it causes. The scale has a minimum of 0 and a maximum of 10. A lower score is a better answer. It will be tested in two conditions, aided with the current Hearing aid, and aided with the new Hearing aid at 10 and 20 days. The difference between the scores from day 10 and day 20 was calculated by subtracting day 20 (new hearing aid) from day 10 (current hearing aid) after both sessions of testing were completed and reported as the mean difference for the group. Regardless of the arm assignment, participants wore the same hearing aids for the lab test on days 10 and 20. | 10 days, 20 days | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Word Recognition - Aided | Subjects will indicate on a touch screen which word that they heard through the loud speaker. The touch screen will give 5 possible answer choices that includes the correct choice and 4 other words that rhyme with the actual word. The test is run in the aided condition with the current Hearing aid and with the new Hearing aid. The test is scored by the percentage of words that they answer correctly. 0 percent is the lowest score possible and 100 percent is the highest. A higher percentage indicates a better score. | 20 days | 
| Sound Quality Rating | The subjects will complete a questionnaire that asks them to rate the quality of different aspects of the hearing aid including sound quality, own voice quality, and the sound quality when in a noisy environment. The scale is from 1 to 5 with 1 being the minimum and 5 being the maximum. A higher score indicates better quality. The questionnaire will be answered for two conditions, aided with the current Hearing aid and aided with the new Hearing aid. The difference between the scores for each condition will be calculated and reported as the mean difference across both arms (moderate hearing loss and severe hearing loss). The difference is not calculated over time points but at the end of the field trial and the assignment order of the hearing aid (new first or current first) does not bear an impact. | 20 days | 
| Word Recognition - Unaided | This measurement is made without any hearing aids. Subjects will indicate on a touch screen which word that they heard through the loud speaker. The touch screen will give 5 possible answer choices that includes the correct choice and 4 other words that rhyme with the actual word. The test is run in the unaided condition. The test is scored by the percentage of words that they answer correctly. 0 percent is the lowest score possible and 100 percent is the highest. A higher percentage indicates a better score. The scores are not dependent on the assignment order of the hearing aids (new or current first) as the measurement is made without hearing aids and a score calculated for each group (moderate or severe hearing loss) and not for each arm.- | 10 days |