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Causes of Deafness and Hearing Loss

by | Aug 8, 2024 | Uncategorized | 0 comments

Deafness and Hearing Loss Overview

Hearing impairment, deafness, or hearing loss refers to the total or partial inability to hear sounds. There are many causes and types of deafness.

A patient with a mild hearing impairment may have problems understanding speech, especially if there is a lot of noise around, while those with moderate deafness may need a hearing aid.

Some people are severely deaf and rely on lip-reading to communicate with others. People who are profoundly deaf can hear nothing at all and can find themselves totally reliant on lip-reading or sign language.

In the United States, around 15  of people over the age of 18 years report some level of hearing loss.

Causes of Hearing Loss

Some diseases or circumstances that can cause deafness include:

Other Conditions

The inner ear is home to some of the most delicate bones in the body, and damage to the eardrum or middle ear can cause hearing loss and deafness in a range of ways.

Hearing Loss vs. Deafness

It is important to distinguish between the different levels of hearing loss.

Hearing loss: This is a reduced ability to hear sounds in the same way as other people.

Deafness: This occurs when a person cannot understand speech through hearing, even when sound is amplified.

Profound deafness: This refers to a total lack of hearing. An individual with profound deafness is unable to detect sound at all.

The severity of hearing impairment is categorized by how much louder volumes need to be set at before they can detect a sound.

Some people define profoundly deaf and totally deaf in the same way, while others say that a diagnosis of profound deafness is the end of the hearing spectrum.

How Does Hearing Work?

Sound waves enter the ear, move down the ear or auditory canal, and hit the eardrum, which vibrates. The vibrations from the eardrum pass to three bones known as the ossicles in the middle ear.

These ossicles amplify the vibrations, which are then picked up by small hair-like cells in the cochlea.

These move as the vibrations hit them, and the movement data is sent through the auditory nerve to the brain. The brain processes the data, which a person with functional hearing will interpret as sound.

Types of Hearing Loss

There are three different types of hearing loss:

1) Conductive Hearing Loss

This means that the vibrations are not passing through from the outer ear to the inner ear, specifically the cochlea. This type can occur for many reasons, including:

  • An excessive build-up of earwax 
  • Defective eardrum
  • Glue ear
  • Ear infection with inflammation and fluid buildup
  • Perforated eardrum
  • Malfunction of the ossicles

Ear infections can leave scar tissue, which might reduce eardrum function. The ossicles may become impaired as a result of infection, trauma, or fusing together in a condition known as ankylosis.

2) Sensorineural Hearing Loss

Hearing loss is caused by dysfunction of the inner ear, the cochlea, auditory nerve, or brain damage.

This kind of hearing loss is normally due to damaged hair cells in the cochlea. As humans grow older, hair cells lose some of their function, and hearing deteriorates.

Long-term exposure to loud noises, especially high-frequency sounds, is another common reason for hair cell damage. Damaged hair cells cannot be replaced. Currently, research is looking into using stem cells to grow new hair cells.

Sensorineural total deafness may occur as a result of congenital deformities, inner ear infections, or head trauma.

3) Mixed Hearing Loss

This is a combination of conductive and sensorineural hearing loss. Long-term ear infections can damage both the eardrum and the ossicles. Sometimes, surgical intervention may restore hearing, but it is not always effective.

Deafness and Speech

Hearing loss can affect speech ability depending on when it occurs.

Pre-lingual Deafness

This is an inability to fully or partially hear before learning how to utter or understand speech.

An individual with prelingual deafness was born with a congenital deformity or will have lost hearing during infancy.

In the majority of cases, people with prelingual deafness have hearing parents and siblings. Many are also born into families who did not already know sign language. They consequently also tend to have slow language development. The few who were born into signing families tend not to face delays in language development.

Children with Pre-lingual Deafness

If children with prelingual deafness are given cochlear implants before the age of 4 years, they can acquire oral language successfully.

Oral language and the ability to use social cues are very closely interrelated. That is why children with hearing loss, especially those with severe symptoms, may not only experience delayed language development, but also slower social development.

As a result, children with prelingual deafness risk becoming socially isolated, unless they attend a school that has a well-run special needs department with other children who have the same condition.

Deaf Subculture in Children

Children who identify with a “deaf subculture,” or those who have learned how to use sign language, might feel less isolated. However, some young people might experience isolation if their parents have not yet learned sign language.

There are cases of children with profound deafness who find themselves on the outer fringes of their hearing peers’ social circles while not being fully accepted by peers with total deafness, due to a lack of fluency in sign language.

Post-Lingual Deafness

Most people with hearing loss have post-lingual deafness. They acquired spoken language before their hearing was diminished. A medication side effect, trauma, infection, or disease may have caused losing their sense of hearing.

In most people with post-lingual deafness, hearing loss onsets gradually.

Challenges

People who experience hearing loss face different challenges, depending on when it occurs and how long it takes to develop. They might have to become familiar with new equipment, undergo surgery, learn sign language and lip reading, and use various communication devices.

A feeling of isolation is a common problem, which can sometimes lead to depression and loneliness. A person with post-lingual hearing loss also has to face the often-distressing process of coming to terms with a disability.

The condition may also pose challenges for household members, loved ones, and close friends, who have to adapt to the hearing loss.

Miscommunication

Miscommunication can place a strain on relationships, not only for the person with the hearing impairment, but also the people around them. If the hearing loss is gradual and has not yet been diagnosed, family members may mistakenly believe that the individual with the condition is becoming more distant.

Unilateral and Bilateral Deafness

Single-sided deafness (SDD), or unilateral deafness, refers to hearing impairment in just one ear, while bilateral deafness is hearing impairment in both.

People with a unilateral hearing impairment may find it hard to carry on a conversation if the other person is on their affected side.

Pinpointing the source of a sound may be more difficult, when compared with those who can hear well in both ears. Understanding what others are saying when there is a lot of environmental noise might be hard.

With little to no background noise, a person with unilateral deafness has virtually the same communicative abilities as a person with functional hearing in both ears.

Babies born with unilateral deafness tend to have developmental speech delays. They may find it harder to concentrate when they go to school. Social activities may be more challenging than it is for children with no hearing problems.

Symptoms

The symptoms of hearing impairment depend on its cause. Some people are born without being able to hear, while others suddenly become deaf due to an accident or illness. For most people, symptoms of deafness progress gradually over time.

Some conditions may have hearing loss as a symptom, such as tinnitus or stroke.

Four Levels of Deafness

There are four levels of deafness or hearing impairment. These are:

  • Mild deafness or mild hearing impairment: The person can only detect sounds between 25 and 29 decibels (dB). They may find it hard to understand the words other people are saying, especially if there is a lot of background noise.
  • Moderate deafness or moderate hearing impairment: The person can only detect sounds between 40 and 69 dB. Following a conversation using hearing alone is very difficult without using a hearing aid.
  • Severe deafness: The person only hears sounds above 70 to 89 dB. A severely deaf person must either lip-read or use sign language in order to communicate, even if they have a hearing aid.
  • Profound deafness: Anybody who cannot hear a sound below 90dB has profound deafness. Some people with profound deafness cannot hear anything at all, at any decibel level. Communication is carried out using sign language, lip-reading, or reading and writing.

Diagnosis

Patients who suspect something is wrong with their hearing will initially go and see their doctor.

The doctor will talk to the patient and ask several questions regarding the symptoms, including when they started, whether or not they have gotten worse, and whether the individual is feeling pain alongside the hearing loss.

Physical Examination

The doctor will look into the ear using an otoscope. This is an instrument with a light at the end. The following may be detected during the examination:

  • A blockage caused by a foreign object
  • Collapsed eardrum
  • An accumulation of earwax
  • Any infection in the ear canal
  • an infection in the middle ear if a bulge is present in the eardrum.
  • Cholesteatoma, a skin growth behind the eardrum in the middle ear.
  • Fluid in the ear canal
  • A hole in the eardrum

General Screening Test

A doctor may ask the patient to cover one ear and describe how well they hear words spoken at different volumes, as well as checking sensitivity to other sounds.

If the doctor suspects a hearing problem, they will probably be referred to either an ear, nose, and throat (ENT) specialist or an audiologist.

Treatment

Treatment depends on both the cause and severity of the deafness.

Sensorineural hearing loss is incurable. When the hair cells in the cochlea are damaged, they cannot be repaired. However, various treatments and strategies can help improve quality of life.

Hearing Aids

These are wearable devices that assist hearing.

There are several types of hearing aid. They come in a range of sizes, circuitries, and levels of power. Hearing aids do not cure deafness but amplify the sound that enters the ear so that the listener can hear more clearly.

Hearing aids consist of a battery, loudspeaker, amplifier, and microphone. 

Risk Factors

Factors that damage or lead to loss of the hairs and nerve cells in the inner ear include the following:

  • Aging: The inner ear breaks down over time.
  • Certain illnesses: Illnesses such as meningitis that cause high fever can harm the cochlea.
  • Loud noise: Being around loud sounds can damage the cells of the inner ear.
  • Heredity: Your genes may make you more likely to have ear damage from sound or from aging.
  • Noises on the job: Jobs where loud noise is constant, such as farming, construction or factory work, can lead to damage inside the ear.
  • Noises at play: Exposure to explosive noises, such as from firearms and jet engines, can cause immediate, permanent hearing loss.
  • Some medicines: These include the antibiotic gentamicin, sildenafil (Viagra) and certain medicines used to treat cancer, which can damage the inner ear. 

Complications

Hearing loss can make life less pleasant. Older adults with hearing loss often report being depressed.

Because hearing loss can make it harder to talk with others, some people with hearing loss feel cut off from others. Hearing loss is also linked to loss of thinking skills, known as cognitive impairment.

Hearing loss also is linked to risk of falling.

Prevention

The following steps can help prevent hearing loss from loud noises and keep hearing loss from aging from getting worse:

Protect your Ears: Staying away from loud noise is the best protection.
Have your hearing tested. If you work around a lot of noise, think about regular hearing tests.
Avoid risks from hobbies and play. Riding a snowmobile or a jet ski, hunting, using power tools, or listening to rock concerts can damage hearing over time. 

Coping and Support

These tips can help you stay connected with hearing loss:

  • Tell your friends and family. Let them know that you’ve lost some hearing.
  • Put yourself in a good position to hear. Face the person you’re talking to.
  • Turn off background noise. For example, noise from a television can make talking and listening harder.

 

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