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

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.

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