Introduction:
Deafness is a disability, and the World Health Organization (WHO) estimates that by 2050 one in every ten people will have disabling hearing loss. Understanding the anatomy of an ear and its functioning can help to improve your knowledge of the loss of hearing.
The Ear:
The ear not only helps in hearing but also aids in the body’s balance.
Parts of the ear include;
Outer Ear
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Pinna - The ear that we see outside is the pinna.
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External Auditory Canal - This tube connects the outer ear with the middle ear.
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Tympanic Membrane - This structure, also known as the eardrum, separates the middle ear from the external ear.
Middle Ear
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Ossicles -These include three small bones; malleus, incus, and stapes. These bones help transmit sound waves to the inner ear.
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Eustachian Tube - This is a canal that connects the middle ear and the back of the nose. It equalizes the middle ear pressure, which is essential for sound wave transfer.
Inner Ear
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Cochlea - The nerves for hearing (auditory nerve) are located in the cochlea. It is a fluid-filled organ.
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Vestibule and Semicircular Canals - The receptors for balance are located in this region.
How Do We Hear Sounds?
External sounds travel through the external auditory canal to hit the tympanic membrane. As the sound waves strike the tympanic membrane, it vibrates. These vibrations are then transferred to the ear ossicles, where the sound gets amplified. This amplified sound then reaches the inner ear to the cochlea. Within the inner ear, these sound waves are converted into electrical impulses, which are then carried by the auditory nerve to the brain. In the brain, these electrical impulses are translated as sounds that we hear.
Are Deafness and Hearing Loss the Same?
While deafness is a total lack of hearing, hearing loss refers to the reduced ability to hear sounds. People with deafness cannot detect sound at all, even with louder volumes. But people with hearing loss can hear or detect sounds with appropriate volumes based on the severity of hearing loss.
What Are the Types of Hearing Loss?
Hearing loss is of three types:
1. Conductive Hearing Loss - Due to blockage of something in the ear at the level of the external ear canal, tympanic membrane, or middle ear, the sound waves cannot reach the inner ear (cochlea) from the external ear in this type of hearing loss. The most common causes of blockage are;
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Earwax build-up.
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Ear infection.
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Eardrum perforation.
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Ossicle malfunctioning (due to ankylosis).
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Reduced functioning of the eardrum due to scar tissue formation following an infection.
2. Sensorineural Hearing Loss - Unlike conductive hearing loss, the sound waves reach the inner ear. Still, processing of the sound waves into nerve impulses does not occur (sensory loss), or the translated nerve impulse does not reach the brain for processing (neural loss). This is due to damaged hair cells in the cochlea. Apart from aging, exposure to loud noises for extended periods also causes hair cell damage. Other causes of sensorineural hearing loss are;
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Brain tumor.
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Inner ear infections.
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Head injury.
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Congenital deformities.
3. Mixed Hearing Loss - This type involves the causes of both conductive and sensorineural hearing loss, such as head injury, genetic abnormalities, chronic ear infections, etc.
What Are the Common Causes of Deafness?
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Aging - Age-related hearing loss or presbycusis is one of the common problems associated with aging, especially in older adults over 65 years of age. The hearing loss is gradual.
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Excessive Earwax Accumulation - Hearing loss due to excessive earwax build-up is the most common and treatable condition.
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Prolonged Exposure to High-Frequency Loud Sounds - Acoustic trauma or sudden hearing is due to exposure to single and extremely loud noise such as a bomb blast or gunshot. It can also cause ringing sounds in the ear. If there is no damage to the tympanic membrane, this hearing loss usually returns to normal over a few days.
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Prolonged exposure to loud noises over 85 decibels can contribute to noise-induced hearing loss.
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Chronic Ear Infections - Children with recurring ear infections are susceptible to hearing loss. Though most children regain their hearing within a month of infection clearance, some lose their hearing permanently.
Less common causes of deafness include:
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Infectious conditions like meningitis, mumps, chickenpox, cytomegalovirus infection, Lyme disease, and syphilis.
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Medication side effects (Streptomycin, Aspirin, cancer medications, Ibuprofen, Gentamicin, Furosemide, etc.).
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Cancers.
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Brain tumors.
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Systemic conditions such as hypothyroidism, arthritis, sickle cell disease, diabetes, etc.
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Congenital abnormalities.
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Autoimmune disorders.
What Signs Do People With Hearing Impairment Show?
People with varying levels of deafness;
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Have difficulty speaking over the phone due to reduced hearing.
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Have difficulty hearing others while in a conversation.
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Find it hard to listen to music and sounds from the television.
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Ask people to repeat the words.
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Stress too much to concentrate on the words while others talk.
How Is Deafness Diagnosed?
Individuals with hearing loss and others surrounding them can initially make out their issue with their difficulty in listening to others. Once they reach a physician’s office, they will be subjected to the following tests to identify the cause of hearing loss.
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Otoscopy - An otoscope is a device with which they can see the inside of your ear to look for eardrum perforation, foreign objects, fluid, earwax impaction, etc.
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Tuning Fork Test - A tunic fork is vibrated and placed behind the ear. Your ability to hear the vibrations will be tested.
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Audiometry - Different tones at different volumes will be directed to one ear at a time via headphones. The level at which hearing becomes diminished is noted.
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Bone Oscillator Test - A headband is placed on the patient with a small square-like box placed behind the ear. It detects how well the vibrations pass through the ossicles.
Can Hearing Loss Be Treated?
Treatment is available for hearing loss (except sensorineural type), but the effectiveness of the treatment varies with the severity of deafness and the cause of deafness. There is no cure for sensorineural hearing loss, but treatment helps improve the quality of life.
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Hearing Aids - These are assistive wearable devices that help amplify the sounds reaching the ear to improve hearing. They do not cure deafness permanently but help listen better.
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Cochlear Implants - If hearing loss is due to problems with the cochlea, then cochlear implants best treat the condition. A microprocessor is placed behind the ear, and a thin electrode is inserted into the cochlea.
People with hearing impairment can benefit from,
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Sign Language - There are different sign languages unique to parts of the world, such as British sign language, American sign language, Norwegian sign language, etc. Based on your region, you can choose to learn sign language and communicate with people through hand gestures, facial expressions, and body language.
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Lip Reading - People who lost their hearing ability at some point in their life and those with residual hearing can benefit from lip-reading by closely watching the lip and tongue movements.
What Are Some Tips to Prevent Deafness?
Congenital deafness and deteriorating hearing ability with age cannot be prevented but age-related hearing impairment and acquired hearing loss can be prevented with the following measures.
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Avoid putting foreign objects within the ears like safety pins, cotton buds, pencils, etc., for removing any blockage on your own.
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Avoid listening to loud music with speakers or headphones. Just keep the volume level comfortable enough to hear (not exceeding 85 dB).
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Use high-quality speakers and headphones. The headphones must be noise-canceling so that you would not need to increase the volume due to external noise.
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If your work involves exposure to extremely loud noises such as disco jockeys, mills, shooting sports, motor racing, etc., wear ear protective devices such as ear mufflers or earplugs.
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If you are taking drugs for any systemic condition, discuss its ototoxic effects and your susceptibility with your doctor.
Conclusion:
Living with deafness and suddenly losing the ability to hear is really frustrating and depressing. But there are always ways to improve your hearing and quality of life unless you are born with it. If you or anyone you know suffers from hearing loss of any kind and severity, feel free to contact our specialist below.
