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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
best suits the 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

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.