Hearing aid technology has come a long way in the last few years, thanksto the computer microchip and digital circuitry. Here are some of thelatest innovations.

Digital technology
Why does music from a CD sound more crisp, clear, and distortion-freethan music from a record or tape? The answer, at least in part, is thedifference between analog and digital sound processing.

Digital hearing aids have one or more microchip processors inside themthat convert analog sound waves into the zeros and ones of computerlanguage. Sound in this format can be processed more quickly and moreefficiently than analog sound waves; in fact, incoming sounds aresampled at a rate of a million or more times per second. The digitalaid's circuitry analyzes these sound levels and frequencies,manipulating them to provide a more efficient match to an individual'shearing profile.

For example, a person with hearing loss may have trouble hearing softsounds, but when some sounds are amplified even a small amount, theybecome uncomfortably loud. Hearing aids with digital compressioncircuitry are able to stratify incoming sounds, detect those that needamplification from those that don't, and process the sound accordingly.

Programmable technology
Digitally programmable hearing aids, which are different from fullydigital aids in that they're not equipped to process all incoming sounddigitally, offer the very useful benefit of being able to sculpt soundto fit a particular individual's unique hearing profile, and can bereprogrammed if there are changes in hearing loss. Programmable aids canbe set up with multiple channels, enabling you to preset and storeseveral different programs, each sculpted to a particular set of soundenvironments. You can then select the appropriate program using a buttonor remote control unit: normal conversation, concert hall, office, ortelephone, for example.

Feedback reduction technology
Feedback has long been a problem for hearing aid wearers. Now we know alot more about feedback, and have developed ways to deal with it.Feedback happens when amplified sound waves escape back out through theear canal and are then re-amplified by the hearing aidÑresulting in thehigh-pitched squeals that set your teeth on edge. Smaller, in-the-canalstyles of hearing aids place components closer to the eardrum,preventing sound waves from escaping, thereby reducing, and ofteneliminating, feedback. Some new aids are also able to detect thesesounds before they become audible and cancel them out, greatly reducingthis frustrating problem.