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Nuts & Bolts: The Perfect Marriage of Technology and Hearing Aids

Martin, Robert L. PhD

doi: 10.1097/01.HJ.0000415187.11161.5d
Nuts & Bolts

Dr. Martin has been a dispensing audiologist in private practice in the San Diego area for more than 30 years. He has been writing Nuts & Bolts since 1989.

Patients want small, dependable, easy-to-use hearing aids. They also want instruments that help with background noise. The perfect hearing aid has yet to be invented, but we are getting close.

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We live in a wonderful time where cell phone and computer technology is constantly updated, and hearing aids share many of the same components — memory chips and software controls, for instance. Some hearing aids are controlled by remote control, and can connect patients to their cell phones through Bluetooth technology.

Six elements can improve hearing aids, bringing them closer to what patients want while markedly reducing background noise: dry kits, chargers and rechargeable batteries, receiver-in-canal hearing aids, Bluetooth compatibility, and remote controls.

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Moisture and ear wax are hearing aids' enemies because they enter through the receiver and microphone ports, occluding the diaphragm, which causes them to break down. Dry kits have been shown to improve hearing aid performance significantly by removing excessive moisture.

Ear wax can get trapped inside hearing aids, and without a dry kit, wax tends to stay moist and stick to the sound tube. Dry kits, along with microphone screens, also prolong directional microphone systems' integrity, but they need to be calibrated to work effectively.

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Battery chargers have been around for years, but intelligent circuits and multicolored light-emitting diodes have been added recently. Color-coded lights inform patients about the system's status when they're charging, malfunctioning, or overheating. Several manufacturers have begun putting heating units inside battery chargers to dry out hearing aids while the batteries recharge.

Nickel cadmium, used in rechargeable batteries years ago, needed to be completely discharged before being recharged effectively. Thankfully this technology has been replaced by nickel-metal hydride, and batteries can be recharged at any point in the discharge cycle. Improved chargers and batteries enhance the efficiency and reliability of hearing aids.

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Popular receiver-in-canal aids have several advantages. If the hearing aid goes dead, the receiver unit can be changed in the office, avoiding manufacturer repairs. The gain and output of these units can be increased by changing the receiver unit. Ultra-high-power receivers are available, providing patients with small hearing aids that produce high-level amplification. These units can be employed initially in an open configuration and converted to an occluded fitting later by adding a custom earmold.

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The battery needed to drive a Bluetooth system is large, making it difficult to integrate into hearing aids. Fortunately, a simple solution has been developed using remote controls that stream Bluetooth signals from cell phones to hearing aids. Cell phone conversations are much easier for patients when they can use both ears.

The amount of ambient noise when using a cell phone can also be manipulated. If a patient wants to hear telephone signals, not the surrounding sound, turn off the hearing aids' microphones and the ambient noise is reduced. If a patient has moderate hearing loss or greater and is wearing earmolds, turning off the microphones completely eliminates outside sound. I have a patient who wears his hearing aids in a bowling alley. When he talks to his wife on his cell phone, he cannot hear the surrounding sounds because hearing loss and earmolds attenuate the noise. He only hears loud, clear telephone signals.

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Many patients want goof-proof hearing aids that are simple enough to use right out of the box. Removing the volume wheels and mechanical switches from hearing aids might ensure this because the patient does not need to adjust the wheel to a desired setting. The remote control offers an easy-to-use resource for making an adjustment.

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Everyone lives happily ever after in a perfect marriage, with spouses enhancing each other's life. The fun is just beginning in the marriage between ideas and technologies. Dry kits reduce repairs and improve real-world performance of directional microphone systems, chargers eliminate battery purchases, sealed case receiver-in-canal instruments are more dependable and can be repaired in office, and Bluetooth technology connects patients to the outside world through their cell phones. The removal of volume controls, mechanical switches, and receiver units from hearing aid cases allows manufacturers to make tiny hearing aids. It looks like the honeymoon is nowhere near ending.

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