Only about 16% of family doctors routinely test hearing. Insist on it! Have your hearing checked periodically -- and consider getting a hearing aid if you aren't hearing as well as you should.

Good news: Today's hearing aids bear little resemblance to the bulky, unsightly devices of 20 years ago. Miniaturization has made them much less conspicuous -- some are almost invisible. Advances in technology allow users to adjust their hearing aids for different types of hearing loss, different sound environments and personal preferences.

NEWEST DEVELOPMENTS

The degree and type of hearing loss dictate which hearing aid will help you the most. Nearly all users can benefit from recent technological advances. These include...

Open-fit devices. These fit outside the ear and are among the most popular hearing aids. They don't require an impression to be taken of the ear canal as with devices that fit inside the ear. Patients can be fitted with the device and take it home the same day.

Open-fit hearing aids have a small component that rests over the ear. This holds a microprocessor with a very fine wire attached to it that feeds into the ear canal where the small speaker is placed. The sound quality rivals that of much larger aids while the device is less visible. These hearing aids also avoid the amplification of your own voice that occurs when your ears are plugged, such as when you wear a hearing aid that blocks the whole ear canal.

Extra advantage: Open-fit hearing aids primarily amplify high frequencies. This means that patients with high-frequency hearing loss -- the most common type -- get help only in the sound range that they need. They aren't subjected to unnecessary amplification of lower sound frequencies as with other types of aids.

Live speech mapping. This new technique ensures that hearing aids deliver the correct volume/sound characteristics for individual patients. A small microphone, connected to a computer, is threaded into the ear canal. The microphone is also able to pick up when sound is being heard by measuring vibrations in the ear canal. When the practitioner speaks into the microphone, the resulting data picked up from the ear canal is fed into the computer, producing an image on the screen. This gives a "map" of such things as high or low frequencies, music and background noise -- and allows the audiologist to make precise adjustments in volume, sound frequency, etc.

Data logging. A tiny computer with a receiver in the hearing aid tracks the types of sound environments (concerts, noisy rooms, etc.) that the patient has been exposed to over a period of weeks or months. An audiologist uses these acoustic logs to determine what kinds of sounds a patient is most exposed to and adjusts the hearing aid settings accordingly.

Artificial intelligence. Some hearing aids contain microprocessors that analyze the data logs and automatically adjust the hearing aid's performance parameters to match the patient's needs.

TYPES OF HEARING AIDS

Nearly all hearing aids can be programmed to match a patient's hearing profile -- amplifying some frequencies and not others, for example. Digital hearing aids incorporate the latest technology and are often superior to other types. Analog hearing aids are much less expensive and are adequate for some patients. There's also an in-between, hybrid type. Pros and cons...

Analog aids have the fewest features. The main adjustment is simply to make things louder or softer. The sound quality isn't great, but some patients -- particularly those who have used them for years -- may prefer them.

Digitally programmed analog. These use the same analog amplifiers as older models, but include a tiny computer to fine-tune the sound. They're more versatile than analog aids, and less expensive than digital.

Digital hearing aids process sounds through a tiny computer. Programmed to compensate for the specific type of hearing loss, they also have preset programs for phone use, conversation, music, etc., that allow you to switch back and forth as needed.

Example: At a loud party, you can push a button that chooses a program that filters out background sounds. Another program might reduce crinkling sounds when reading the paper.

DIFFERENT STYLES

In-the-canal hearing aids. Some hearing aids are nearly invisible because they fit entirely in the ear canal. These models are a good choice for people with mild hearing loss who dislike the appearance of larger models.

Drawbacks: They're expensive... aren't powerful enough for severe hearing loss... have tiny batteries that last less than a week... the small controls are difficult for some users to manage.

Behind-the-ear models (including open-fit devices) have a component that fits behind the ear (like an eyeglass earpiece) and a mold that fits in the ear canal. Bulky compared with other models, they've become smaller and less visible in recent years. They can correct moderate to severe hearing loss, and the controls are large enough to manipulate easily.

In-the-ear models do not fit as deeply inside the ear as in-the-canal hearing aids. But they're barely visible and may include such features as a telephone coil (to eliminate feedback when using a telephone headset), that don't fit on smaller models. They are good for those with mild to moderately severe hearing loss.

Body-worn hearing aids contain all of the electronics in a pager-sized box that's worn on the belt or carried in a pocket. A wire runs from the box to the ear canal. They're mainly used by people with severe hearing loss.

Many patients are tempted to get a hearing aid that incorporates all of the latest technology even if they don't really need it. Extra features add greatly to the cost. It doesn't make sense to get a feature-laden hearing aid if you aren't likely to spend the time needed to learn how to use it, or if you spend most of your time in the same kind of sound environment.

IMPLANTABLE HEARING AIDS

The aids described above might not work for patients with certain medical ear conditions or severe/profound hearing loss. An option might be to get an implantable hearing aid, such as a...

Bone-anchored conduction hearing aid. A small titanium screw is attached to the bones of the middle ear during an outpatient procedure. Sound causes the screw to vibrate. These vibrations are transmitted by electrical devices directly to the inner ear.

Cochlear implant. An electrical receiver is surgically implanted under the skin behind the patient's ear. An electrode from the receiver goes into the cochlea, a snail-like structure in the inner ear. The signals from the electrode are picked up by the auditory nerve and travel to the brain.

Implantable hearing aids may produce clear sound, but they're generally used only in patients who can't use conventional hearing aids.

Bottom Line/Retirement interviewed Ross J. Roeser, PhD, professor of audiology and executive director of the Callier Center for Communication Disorders at the University of Texas, Dallas. He is editor of Roeser's Audiology Desk Reference (Thieme Medical).