Researchers are looking at ways to apply new signal processing strategies to the design of hearing aids. Signal processing is the method used to modify normal sound waves into amplified sound that is the best possible match to the remaining hearing for a hearing aid user. NIDCD-funded researchers also are studying how hearing aids can enhance speech signals to improve understanding.

In addition, researchers are investigating the use of computer-aided technology to design and manufacture better hearing aids. Researchers also are seeking ways to improve sound transmission and to reduce noise interference, feedback, and the occlusion effect. Additional studies focus on the best ways to select and fit hearing aids in children and other groups whose hearing ability is hard to test.

From the Research Lab

Another promising research focus is to use lessons learned from animal models to design better microphones for hearing aids. NIDCD-supported scientists are studying the tiny fly Ormia ochracea because its ear structure allows the fly to determine the source of a sound easily.

Scientists are using the fly’s ear structure as a model for designing miniature directional microphones for hearing aids. These microphones amplify the sound coming from a particular direction (usually the direction a person is facing), but not the sounds that arrive from other directions.

Directional microphones hold great promise for making it easier for people to hear a single conversation, even when surrounded by other noises and voices.

“Now I wake up each morning to the sound of birds”

A cochlear implant is a small, complex electronic device that can help to provide a sense of sound to a person who is profoundly deaf or severely hard-of-hearing. The implant consists of an external portion that sits behind the ear and a second portion that is surgically placed under the skin. An implant has the following parts:

• A microphone, which picks up sound from the environment
• A speech processor, which selects and arranges sounds picked up by the microphone
• A transmitter and receiver/stimulator, which receive signals from the speech processor and convert them into electric impulses
• An electrode array, which is a group of electrodes that collects the impulses from the stimulator and sends them to different regions of the auditory nerve

We hope the following FAQ gives you a better understanding of this powerful little device.

How does a cochlear implant work?
A cochlear implant is very different from a hearing aid. Hearing aids amplify sounds so they may be detected by damaged ears. Cochlear implants bypass damaged portions of the ear and directly stimulate the auditory nerve. Signals generated by the implant are sent by way of the auditory nerve to the brain, which recognizes the signals as sound. Hearing through a cochlear implant is different from normal hearing and takes time to learn or relearn. However, it can aid in the recognition of warning signals and other sounds in the environment. Phone conversation is also enhanced.

Who gets cochlear implants?
Children and adults who are deaf or severely hard-of-hearing can be fitted for cochlear implants. According to the Food and Drug Administration (FDA), at the end of 2006, more than 112,000 people worldwide had received implants. In the United States, roughly 23,000 adults and 15,500 children have received them.

Adults who have lost all or most of their hearing later in life often can benefit from cochlear implants by learning to associate the signal provided by an implant with sounds they remember. This often provides recipients with the ability to understand speech solely by listening through the implant, without requiring any visual cues such as those provided by lip-reading or sign language.

Cochlear implants, coupled with intensive post implantation therapy, can help young children to acquire speech, language, and social skills. Most children who receive implants are between two and six years old. Early implantation provides exposure to sounds that can be helpful during the critical period when children learn speech and language skills. In 2000, the FDA lowered the age of eligibility to 12 months for one type of cochlear implant.

How does someone receive a cochlear implant?
A cochlear implant requires both a surgical procedure and significant therapy to learn or relearn the sense of hearing. As with all surgeries, risks should be weighed and costs considered. Not all health insurance covers the expense of a cochlear implant.

The results of a cochlear implant vary. Not everyone performs at the same level with this device and speech-language pathologists and Audiologists are frequently involved in this learning process. Prior to implantation, all of these factors need to be considered.

What does the future hold for cochlear implants?
With advancements in technology and continued follow-up studies with people who already have received implants, researchers are evaluating how cochlear implants might be used for other types of hearing loss.

NIDCD is supporting research to improve upon the benefits provided by cochlear implants. It may be possible to use a shortened electrode array, inserted into a portion of the cochlea, for individuals whose hearing loss is limited to the higher frequencies. Other studies are exploring ways to make a cochlear implant convey the sounds of speech more clearly. Researchers also are looking at the potential benefits of pairing a cochlear implant in one ear with either another cochlear implant or a hearing aid in the other ear.

If you are a candidate for a cochlear implant, it is important to remember that the device does not restore normal hearing. It can, however, provide a useful representation of sounds to aid you in understanding speech.

Severe hearing loss doesn’t have to leave you suffering in silence

Discover how to clear the way for better hearing.

At the end of the auditory canal lies the middle ear, which is composed of the eardrum and three small bones, known as the hammer, the anvil and the stirrup. When soundwaves hit the eardrum, it vibrates and moves the hammer. The hammer moves the anvil, which moves the stirrup, transmitting the vibrations into the inner ear. The middle ear functions to amplify sound, which is why significant hearing loss can result from any disruption in any of its parts.

The inner ear consists of the cochlea and the nerve of hearing. It converts soundwaves into nerve impulses that travel to the brain via the movement of tiny hair cells. It is the brain that allows you to hear, as long as the message it’s receiving is not distorted due to problems in the process just described.

Want to learn more?

Click here to learn about the types and causes of hearing loss.
Click here to learn what happens during a hearing test appointment.
Click here to learn about hearing aid information.

Knowledge is power…the power to hear better!