A person’s hearing levels are measured using an audiogram, like the one shown here. An audiogram displays the loudness of sounds in decibels (dB) and their pitch or frequency in hertz (Hz). Hearing within the typical range is generally shown at 20 dB or less, while hearing levels below this range may indicate some degree of Deafness or hearing loss in one or both ears.
On this audiogram, the typical hearing range appears above the 20 dB line near the top. The blue area is known as the speech banana because it represents the range in which many speech sounds occur. The objects shown across the audiogram also have a purpose: they demonstrate the typical pitch and loudness of familiar environmental sounds. The further down the audiogram a sound appears, the louder it needs to be for a person to hear it.
When a person’s hearing is tested, their hearing thresholds are recorded on an audiogram like the one shown here. The two lines represent the softest sounds the person can hear at different pitches. The red line represents the right ear, while the blue line represents the left ear. Sounds above these lines are generally too quiet for the person to hear, while sounds at or below the lines may be audible because they are louder.
The grey area is known as the speech banana and represents the pitch and loudness of many common speech sounds. In this example, the person’s hearing thresholds fall below most of the speech banana. This indicates that, without hearing technology or other support, they would be unable to hear most speech sounds.
What is Deafness and Hearing Loss?
How does hearing work?
The Parts of the Ear
The ear is divided into three main parts:
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The outer ear includes the pinna—the visible part on the side of the head—and the ear canal. It collects sound and directs it towards the eardrum.
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The middle ear contains the eardrum and three tiny bones called the ossicles. These bones transmit sound vibrations from the eardrum to the inner ear.
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The inner ear contains the cochlea, a small, snail-shaped organ responsible for hearing. It also contains the semicircular canals, which contribute to balance.
The auditory nerve connects the inner ear to the brain and carries electrical sound signals from the cochlea.
How Hearing Works
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The pinna collects sound and directs it through the ear canal towards the eardrum, causing the eardrum to vibrate.
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These vibrations move the three ossicles—the smallest bones in the human body. The ossicles transmit the vibrations into the cochlea, causing the fluid inside it to move.
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This movement stimulates tiny sensory hair cells inside the cochlea. The hair cells convert the movement into electrical signals.
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The auditory nerve carries these signals to the brain, where they are interpreted as recognisable sounds
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Are you born Deaf or does it happen over time?
BOTH CAN HAPPEN!!
Hearing loss at birth is called a Congenital hearing loss, and hearing loss after birth is called an Acquired hearing loss.
CONGENITAL HEARING LOSS
ACQUIRED HEARING LOSS
What causes Hearing Loss?
Hearing loss can have many different causes, including:
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Damage to the inner ear
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Age-related changes
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Certain illnesses or medical conditions
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Prolonged or sudden exposure to loud noise
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A build-up of earwax
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Abnormal bone growth within the ear
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Ear infections
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Tumours affecting the ear or auditory nerve
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A ruptured eardrum
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Genetic or inherited conditions
In some cases, the cause of a person’s hearing loss may remain unknown.
Two main types of Hearing Loss
Conductive hearing loss occurs when sound cannot travel effectively through the outer or middle ear to reach the inner ear. As a result, quieter sounds may be difficult to hear, while louder sounds may seem muffled or unclear. Some causes of conductive hearing loss can be treated medically or surgically; however, treatment options and outcomes vary depending on the cause and the individual.
Sensorineural hearing loss occurs when there is damage to the inner ear—particularly the sensory hair cells within the cochlea—or to the auditory nerve that carries sound signals to the brain. This type of hearing loss is usually permanent; however, hearing aids may improve access to sound for some people. People with severe or profound sensorineural hearing loss may be eligible for a cochlear implant following a detailed assessment.
Can you have both types of Hearing Loss?
Mixed hearing loss is a combination of conductive and sensorineural hearing loss. This means that there are difficulties affecting the outer or middle ear, as well as the inner ear or auditory nerve.
This is the type of hearing loss that I have.
When I was younger, the conductive component made it difficult for doctors to identify the full extent of my sensorineural hearing loss. They first needed to address the problems affecting my outer and middle ear through procedures such as grommet insertion and reconstructive surgery. Once these issues had been treated, my sensorineural hearing loss could be more accurately diagnosed and addressed.
How do Hearing Aids work?
Hearing aids may support people with different types and degrees of hearing loss, including conductive and sensorineural hearing loss. The most suitable device depends on the individual’s hearing levels, needs and circumstances.
Hearing aids generally work through three main components:
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The microphone collects sound from the surrounding environment and converts it into a digital signal.
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The processor and amplifier adjust and increase the strength of the signal according to the person’s hearing needs.
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The speaker or receiver delivers the processed sound into the ear.
The three main hearing-aid styles are behind-the-ear, in-the-ear and in-the-canal devices. Behind-the-ear hearing aids can generally provide greater amplification and may support a wider range of hearing levels. However, the most appropriate style is not determined by the degree of hearing loss alone. An audiologist will also consider factors such as the person’s age, ear shape, comfort, lifestyle and required features.
How do Cochlear Implants work?
Cochlear implants may be suitable for some people with moderate to profound sensorineural hearing loss, particularly when hearing aids provide limited benefit. They are not generally used to treat conductive hearing loss alone.
A detailed assessment process is required to determine whether a cochlear implant is appropriate for an individual. The length of this process varies depending on each person’s circumstances and needs.
A cochlear implant includes both external and internal components. The external sound processor uses a microphone to collect sound and convert it into digital signals. These signals are transmitted to a receiver placed beneath the skin behind the ear. The receiver then sends electrical signals to an electrode array positioned inside the cochlea.
Cochlear implants do not restore typical hearing. Instead, they bypass damaged parts of the inner ear and directly stimulate the auditory nerve, providing the brain with access to sound.
