Hearing Aids

Hearing aids are small electronic devices used to improve hearing loss. Think of them as “mini-amplifiers” that pick up certain sounds and make them louder. Today the amplification process has gone almost exclusively digital. All hearing aids are customised to receive and transmit sounds to match your own level of hearing loss.

How They Work

Early hearing aids were analogue in nature but since the 1980’s have largely moved over to digital technology. The general process of how they work however is the same. Starting with sounds in the external environment, the hearing aid first receives the sounds, typically through some form of microphone. Received sound waves are then recorded and converted. In older analogue devices the conversion process resulted in electrical signals or impulses. With digital aids the recorded sounds are converted into numerical codes, which the hearing aid’s amplifier then analyses. Hearing aids are pre-programmed by the manufacturer based on the severity and nature of the hearing aid user’s hearing loss. Finally, the now analysed and amplified information is converted back to sound waves and sent to the brain via a speaker. Where these three parts of a hearing aid – the microphone, the amplifier and the receiver – are placed depends on the style of the aid.

Styles

Although all hearing aids utilise the same basic components to collect sounds from your external environment and pass them along to your brain, there are different styles available. The differences across styles centre on where the hearing aids are located and their size. Ranging from smallest to largest here are some currently popular styles:
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• Completely-in-canal
• In-canal
• Half-shell
• Full-shell
• Behind-the-ear

Hearing Aid Styles: Advantages And Disadvantages

Hearing aids placed within the ear canal are the least visible but their size leads to some limitations. Completely-in-canal aids – those inserted the deepest into the canal – have shorter battery life and no room for volume adjustment controls. In-canal aids do not go as deep into the canal so they can include volume control and other features. However, due to their placement and small size, these features can be difficult to adjust. Half-shell aids fit into the lower half of the ear bowl and their larger size makes them easier to adjust. Full-shell aids fill the entire ear bowl and are the most visible of the in-ear aids. However, their size enables larger and longer-lasting batteries and additional and easier to adjust features, such as directional microphones. Behind-the-ear aids place a larger amplifier directly behind the ear, attached to the ear with a hook. Sounds are received and analysed here and then sent to an ear mould placed within the ear canal. This type provides the highest amplification available in hearing aids but they are also very visible. Open Fit is another behind-the-ear style that is smaller, less visible, and does not place an ear mould into the canal. As you would expect, decreased size leads to decreased functionality, smaller batteries and fewer and smaller controls.

Should You Get One?

If you think you might have a hearing loss, go and see your local doctor. Many people are amazed when their hearing loss disappears after a blob of earwax is removed! If no obvious medical conditions – such as infections or visible tumours – are present, your doctor should then send you to a specialist. Otolaryngologists focus on eye, ear, nose and throat disorders and can more accurately diagnose the specific causes of the hearing loss. Audiologists will test your hearing to determine the nature and severity of the loss. These test measurements will later be used to program the hearing aid you select. Audiologists are generally more knowledgeable when it comes to answering questions about which type of hearing aid would be the best fit for your particular level of hearing loss. You should be aware that no hearing aid will return you to normal hearing. With a hearing aid you will receive more and louder “sounds” – including distracting background noise – but the sounds will come across to your brain as a little strange and different. It takes some time to get accustomed to a hearing aid.

Care And Maintenance

Manufacturers’ instructions provide all the information needed to take care of the hearing aid you purchase. Adjusting to using the hearing aid varies by individual. A good practice is to maintain frequent contact with your audiologist or hearing aid provider. They can advise you on how long to wear the aid initially, how to make adjustments and so forth.

Future Developments

Some of the newest hearing aids available offer built-in telephone blue-tooth technology. Advances in digital technology are already producing hearing aids with several built-in directional microphones which can filter out background noise. More and more of the features previously available only in larger hearing aids will be added to the smaller, less visible and less invasive aids. In the not-too-distant future, some hearing aids will be surgically implanted and therefore completely invisible. Wireless technology is already adding telephonic features to some hearing aids. Perhaps the greatest advancement will come in the capability of converting signals received by the hearing aid into sounds that more closely approximate what fully functional hearing provides.

Additional Information

Since hearing aids are distributed through for-profit companies there can be a lot of misleading and outright false information out in the public domain. “Let the Buyer Beware” certainly applies here. Website searches can provide a host of information but when it comes to selecting a hearing aid. Seek out the opinions of professional audiologists and check with family and friends for success and horror stories. Finally, medical centres of major universities are always an excellent source of current information.