21st century Hearing Aid Technology

In the good old days, hearing aids amplified sound pretty much the same whether soft or loud, low-pitched or high-pitched, speech or noise.  But the modern digital hearing aid adjusts automatically to the sound around you, using a program custom-designed for your own hearing pattern.

For example, for someone with good hearing in the low pitches but hearing loss in the high pitches, the instruments are programmed to provide no amplification where hearing is good and significant amplification for the high-pitched sounds.

As microchips have gotten smaller and faster, engineers, hearing scientists and programmers have used the advanced processing capabilities to improve older techniques.  Other developments, such as speech recognition and wireless connectivity, are entirely new approaches. 

For example, directional microphones provide more amplification for sounds coming from the front and less amplification for sounds coming from the back.  Hearing aids now use digital technology to control directionality automatically and more precisely. 

Compression is the technique of automatically reducing amplification as sound gets louder.  This is important because people with sensorineural hearing loss are often hypersensitive to loud sounds.  Older hearing aids offered compression, but the amount was fixed.   The 21st century hearing aid allows compression to be customized, depending on the person’s sensitivity to loud sounds.  The compression can also be programmed separately for different pitches.

Noise suppression detects incoming sound that is relatively constant (typical of noise) and then reduces amplification of that sound.  The result can be improved comfort and word understanding in noisy settings.  While effective, noise suppression programs do not eliminate background noise entirely.    

Telecoils have always been important for people with hearing loss who have difficulty using a telephone.  But telecoils can be awkward to use, with a telecoil switch that must be moved to the “T” position.  New telephone detection circuits allow the hearing aid to detect when a telephone is brought up to the ear and then automatically switch to the telephone mode, allowing the hearing aid to amplify sound from the telephone (but no other sounds).

Feedback reduction programs the presence of feedback (the whistling sound caused by sound leakage from the hearing aid).  The hearing aid can then minimize or cancel the feedback.  Because digital hearing aids control it so effectively, feedback can be virtually eliminated, even for individuals with severe hearing loss.

Speech recognition circuits use the power of digital technology to detect and then provide additional amplification when speech is present.  This is a relatively new technique and research continues to investigate ways to identify speech and process it differently than competing noise.

Wireless capability uses technology similar to Bluetooth to connect wirelessly to a cell phone, television set or landline telephone using a wireless transmitter connected to the phone or television.  This allows the signal to be sent directly into your hearing aids.

Wireless technology also allows two hearing aids to communicate with each other, sharing information such as directionality and the hearing aid settings.  For example, the hearing aid can automatically go into the telephone mode (amplifying only the voice on the phone) and at the same time signal the hearing aid in the opposite ear to turn itself lower.

Millions of people have already benefited from these advances.  Hearing aids still cannot – and never will – restore “normal hearing” to people with hearing loss.  Ironically, the most common complaints that remain involve other manmade technologies, such as movies and television.  Still, we have come a long, long way from the days when hearing aids simply made sounds louder.© 

Keeping Your Hearing Aids in Good Shape

Hearing aids can malfunction at any time for no apparent reason.  Sometimes it seems as if hearing aids stop working the day before a family wedding or the night before you leave on a trip.  About 50% of the repairs of in-the-ear and canal hearing aids are due to earwax (cerumen).  If your aid is using too many batteries, sounds weak, or has no sound at all, it may be due to earwax blocking the sound opening.  There are several things you can do to minimize this problem. 

Many hearing aids have built in wax guards.  These should be replaced occasionally.  If your aids don’t have a wax guard, use a wax loop or brush to remove cerumen and debris from the sound opening.  Be sure not to push the wire or brush into the sound opening itself. 

If wax is a frequent hearing aid problem, consider periodic removal of wax from your ear canals using an over-the-counter wax removal system.  Do not use cotton swabs, as this pushes the wax further into your ear, possibly damaging your ear.

Some other tips:

• Throw away your old batteries to avoid mixing them with good ones.
• Use only high-quality batteries.  They will last longer and provide a more uniform power supply.  Store batteries at room temperature.
• Don’t use hair spray or powder with your hearing aids in place.
• Avoid excessive moisture.
• Store your hearing aids in a dehumidifier container at night.