Hearing

How hearing works

The human ear is made up of three key parts: the outer ear, the middle ear and the inner ear. The outer ear has two parts: the pinna and the external auditory canal, which we often simply refer to as the ear canal. The pinna’s major function is to direct and amplify sound in the canal. While the pinna is made of fibrocartilage, the canal is primarily composed of bone and cartilage. The middle ear is made up of the eardrum, the tympanic cavity and the Eustachian tube. The eardrum—a membrane located at the end of the ear canal—vibrates, serving to amplify sound. The tympanic cavity houses the three smallest bones in the human body: the malleus, the incus and the stapes. The smallest of these is the stapes, which is a maximum of 4 mm long. The Eustachian tube (or auditory tube) connects the pharynx to the middle ear and essentially serves to equalize pressure by opening and closing. It is therefore often the cause of earaches felt as a result of drops in pressure, much like the ones we experience in an airplane.

The inner ear has two main functions. First, it serves to send sounds to the brain and helps us keep our balance. This part of the ear includes the cochlea, a snail shell-shaped organ that contains sensory hair cells. These hair cells are set in motion in response to the movement of liquids called endolympha and perilymph. The cells are often responsible for hearing loss—in fact, damaged or destroyed hair cells can be found in the cochlea of 90% to 95% of hearing-impaired persons. Simply put, sound is captured by sensory cells found in the cochlea which are then transformed into nerve impluses that make their way to the brain.

As mentioned earlier, the inner ear is also responsible for providing us with our balance. Essentially, it is three tiny canals filled with endolympha that inform the body of its spatial position. For example, if you turn around very quickly and stop suddenly, you might start to feel dizzy. This is caused by the constant movement of the liquid contained in the canals. Some people even suffer from an inner ear disease known as Meniere’s Disease.

Types of hearing loss

There are three main types of hearing loss:

1. sensorineural
2. conductive
3. mixed

Approximately 85% to 90% of hearing-impaired persons suffer from what we call sensorineural hearing loss. The root cause of this problem generally lies in the cochlea, in the inner ear. The problem may also stem from the auditory nerve (8th nerve), but this only occurs in rare cases termed retrocochlear hearing loss.

As explained previously, damaged or destroyed sensory cells in the inner ear generally cause different degrees of hearing loss. High-pitched sounds are generally the first that become difficult to hear. Then, as hearing fades, other sounds also become imperceptible. This means that, at the onset of the problem, only certain parts of words are hard to make out.

Loss of transmission occurs in the outer ear and/or the middle ear. Frequently, rigidity of the auditory ossicles is the cause of this particular problem. Mixed hearing loss affects the middle ear and inner ear simultaneously. Your specialist can provide a detailed explanation of where your particular hearing problem lies.

Listening strategies

It is important to understand that a hearing aid cannot restore your hearing. That is why applying listening strategies is also recommended in some cases. These strategies apply not only to the hearing-impaired individual, but also to the members of his family. Here are a few recommendations for family members and friends:

• look at the hearing-impaired person when speaking
• do not speak to him from another room
• choose quiet surroundings
• eliminate distracting noise whenever possible
• make sure there is always enough lighting for him to read your lips
• get the other person’s attention before speaking
• maintain a normal distance between you and the hearing-impaired person when speaking (4-5 feet)
• speak up slightly when necessary
• when you are in groups, take turns when speaking
• sit on the side on which he wears a hearing aid (if he wears only one)

For the hearing-impaired person:

• turn the volume down on your hearing aid when you are in a noisy environment
• stand close to the person who is speaking to you
• read the other person’s lips
• sit with your back to the wall when in a large room or restaurant
• when in the car, turn down the radio, direct the air conditioning away from your hearing aid and adjust your hearing aid
• at the restaurant, always ask for a table in a quiet area
• in a classroom setting, choose a seat in the front row and let your teacher know that you are hard of hearing
• If you have a digital hearing aid, use the “Noise” setting, if you have one

There are more sophisticated hearing aids that can help you hear more clearly in noisy situations. Ask your audioprosthesist for more information.

Early signs

Did you know that over 700,000 people in Québec alone are hard of hearing to one degree or another? That’s 10% of the population! There are many early warning signs that you may be suffering from hearing loss. For example, people with hearing loss tend to:

• ask others to repeat
• turn up the television
• hear one word instead of another
• find it difficult to have a conversation in a noisy environment (party, restaurant)
• speak more loudly
• have difficulty hearing someone if their back is turned or if they are in another room
• isolate themselves
• have less conversations with others and cut back on social activities
• on some occasions, have constant or intermittent ringing in their ears
• think others are muttering

In most cases, hearing loss worsens with every passing year until the signs become impossible to ignore. It is usually best to fit the hearing-impaired individual with a device as early as possible in an effort to minimize the effects of long-term hearing loss and make it easier for them to adapt to a hearing aid. If you think you might be among the 700,000 people suffering from hearing loss, please make an appointment for a free hearing test at our offices as soon as possible.

The audioprosthesist’s role

Audioprosthesists are the only health professionals in Québec authorized by law to fit, sell, adjust and replace hearing aids. When adjusting a hearing aid, the audioprosthesist’s objective is to properly assess the specific needs of that particular patient. By taking precise audiometric tests, he is able to discern the particular hearing problem suffered by the patient. It is also the audioprosthesist’s job to inform his patient of the advantages and disadvantages of different types of hearing aids and help him decide which particular device best suits his needs.

The hearing-aid specialist then chooses the circuit and the different features of the hearing aid. He explains to the patient how to adapt to this new tool and use it properly. He does so by testing out the hearing aid’s different applications with the patient. Once fitted with a new hearing aid, the patient leaves to enjoy a few weeks with his corrected hearing, after which he will return for a follow-up visit with his audioprosthesist. During the follow-up visit, certain tests are performed while the patient wears his hearing aid in an effort to ensure the audioprosthesist that the patient is completely satisfied with the device’s performance. After this follow-up visit, the patient must continue to see his audioprosthesist every 6 months. These appointments give the audioprosthesist a chance to verify or repair the hearing aid, make any necessary electroacoustic adjustments and test the patient for any changes in his hearing. If you experience any problems with your hearing aid, it is imperative that you inform your audioprosthesist as soon as possible—remember that he is your hearing-aid specialist, and therefore the best suited to help you.

Of course, the audioprosthesist’s job extends far beyond that of adjusting hearing aids for his patients. It is also important for him to understand, listen to and guide his patients. When meeting with patients, he strives to learn about their tastes, desires and expectations. By doing so, he is then able to adequately guide them in choosing the hearing aid that best suits their needs and lifestyle. Different people react to using a hearing aid in different ways. It is the audioprosthesist’s job to listen to his patients in order to be able to properly assess their needs, and it is also his job to calm their worries or fears about using a hearing aid. The more your audioprosthesist knows about you, the more he will know which particular sounds are important to you and the better equipped he will be to make sure you can hear them. If you are more concerned about wanting a hearing aid that is small and discrete, your audioprosthesist will do some research to find the smallest device that can meet your particular needs. Simply put, it is of the utmost importance that you talk to your audioprosthesist about your particular tastes, your fears, your lifestyle, problems you might experience after getting your hearing aid or even your feelings about wearing a hearing aid. Remember that your audioprosthesist is there as a technical professional, but also seeks to learn more about you, help you and understand you.

At the offices of Laniel & Associés, Audioprothésistes, there are 3 audioprosthesists available to help you 5 days/week as well as a few evenings to ensure that you can get an appointment as quickly as possible.

Equipment

Audioprosthesists require a range of specialized equipment to perform tests. Typically, an audioprosthesist uses an audiometre and a sound-proof booth to conduct the different tests required to determine a patient’s degree of hearing loss. He also uses an electroacoustic analyser to check the performance of hearing aids as well as an In-Situ analyser to verify patient performance with the hearing aids. The repair lab is equipped with a complete set of tools, parts, welding instruments and microscopes, speaker amplifiers for free-field exams, a videootoscope as well as different buffing wheels for modifying earshells.