Aids for improving hearing

Hearing aids

Hearing aids are devices that amplify sounds. They can be used in both conductive and sensorineural hearing loss. Their use usually improves the affected person’s quality of life considerably. However, among people who are profoundly deaf, some may get very limited (or even zero benefit) from hearing aids, but this is not predictable from the audiogram alone. They last 5 years on average and in the UK they can be obtained free, from the NHS, or purchased privately from a registered Hearing Aid Dispenser.

The hearing aid consists of-:

• A microphone to pick up sound signals
• A battery powered amplifier to amplify sound signals
• A receiver to deliver the amplified sound to the ear canal

Digital aids are programmable to individual hearing requirements. The settings can be controlled to match the hearing loss frequency only, thereby cutting out amplification of background noises. However, the benefit is limited in real life situations. Many digital hearing aids are designed to reduce steady kinds of background noise, such as the rumble of traffic or the whirr of a fan. This can make listening more comfortable, but it does not necessarily enable the user to pick out a single voice from everything else going on, especially when several people are talking at once. Directional microphone systems amplify sounds that come from in front of the person more than sounds to the side or behind them. This makes it easier for the person to focus on what they want to listen to in a noisy place. The user can switch between directional and all round sound, depending on what they need to hear at the time. Some digital aids will detect where the noise is coming from and automatically adjust to reduce the noise selectively. However, a hearing aid cannot know what the person wants to listen to. Directional hearing remains a problem for many hearing aid users. They are customised to the person, and are normally available in the “behind the ear” style, on the NHS.

Hearing aids require reasonable care and cleaning and are powered by dry batteries which need replacing from time to time.

Cochlear Implants

Cochlear Implants are surgically - implanted devices, which electrically stimulate the auditory nerve in the cochlea.

Cochlear Implants are most suitable for adults with severe or profound sensorineural hearing loss that occurred after the development of language skills, whose hearing does not improve with conventional hearing aids. They are also used in children with severe or profound hearing loss. All patients require careful assessment within a specialist unit.

Outcomes depend on assessment, expectations, cause of the hearing loss and rehabilitation. Many can hear well but those in whom there is a less dramatic improvement can usually hear environmental sounds like traffic, sirens and other warning noises. They may also experience an improvement in their ability to lip read, use a voice telephone and use their voice more confidently.

Middle Ear Implants

Middle Ear Implants are surgically implanted devices, which mechanically assist sound transmission into the inner ear.

Bone Anchored Hearing Aids

Bone Anchored Hearing Aids are surgically implanted devices that transmit sound directly to the inner ear through the bones of the skull.