Deafness and Hearing Loss

Deafness, hearing impairment, or hearing loss is the inability to perceive sounds. Deafness is characterized by mild and severe symptoms for different patients. According to the National Institute on Deafness and Other Communication Disorders (NIDCD), around 25% of people between the ages of 65 and 74 suffer from hearing impairments.

In some cases, patients who are deaf rely on lip-reading to communicate effectively with others, while individuals who are severely deaf use sign language.

How Does Hearing Occur?

Have you ever been curious about how hearing occurs? Here is a brief explanation of the hearing process. Hearing occurs when sound waves travel from the outer ear to the eardrum, a thin layer of skin between the outer and middle ear. There are structures in the middle ear known as ossicles made up of stirrup, anvil, and hammer. The ossicles and eardrums work in harmony to increase the sound vibrations transmitted to the inner ear.

On reaching the inner ear, vibrations move through a liquid substance, the cochlea.  The cochlea, a snail-shaped feature found in the inner ear, contains nerve cells full of tiny hairs. The hairs convert sound waves into electrical signals transmitted through the brain. Electrical signals are interpreted into particular sounds. The difference, like sound vibrations received in the brain, determines how the brain interprets the sounds.

What Causes Hearing Loss?

Numerous conditions can result in loss of hearing, the most common being the natural aging process and exposure to loud noise. Research by the American Speech-Language-Hearing Association (ASHA), the most frequent cause of deafness is caused by sensorineural hearing loss (SNHL), conductive hearing loss, and mixed hearing loss. Other factors that could result in loss of hearing include:

  • Lyme disease

  • Syphilis

  • Cytomegalovirus

  • Meningitis

  • Hypothyroidism

  • Severe Arthritis

  • Mumps

The above predispose patients suffering from these illnesses to deafness. Medically the severity of the hearing disorder is measured by the volume required for a patient to detect the sound. These are the various types of hearing loss.

Sensorineural Hearing Loss (SNHL)

SNHL occurs when the inner ear nerves, cochlea, auditory nerve, and hair cells suffer damage due to exposure to noise or congenital deformity, head trauma, and aging. Damage to these organs directly affects the nerves from the inner to the brain. Unfortunately, some infections like mumps, measles, scarlet fever, and meningitis may cause SNHL.

Sudden SNHL is categorized as an otologic emergency and can be treated with corticosteroids. Doctors highly recommend corticosteroids because they help reduce inflammation after exposure to loud noise and cochlea swelling—deteriorating sensorineural hearing loss due to Meniere's disease characterized by vertigo and tinnitus. Meniere's disease is treated using diuretics, and vertigo can be eliminated through several surgical procedures.

The most prevalent form of hearing loss due to advancement in age can be managed using hearing aids. In cases where hearing aids fail to address the condition, surgical treatment is recommended for cochlear implants. If you suffer severe damage to the inner ear, medical interventions can not prevent hearing loss.

Conductive Hearing Loss

Conductive hearing loss is when sound vibrations cannot travel through the outer ear to the ossicles in the middle ear. People experiencing this condition are unable to perceive soft and muffled sounds. Conductive hearing loss is caused by allergies, ear infections, and wax buildup in the ear and swimmer's ear. If left untreated, ear infections may result in scar tissue that reduces eardrum function.

Antifungal drugs are administered to treat ear infections. In the case of tumors, surgery is necessary. According to medical assessment, the hearing nerve's condition can determine the best solution for amplification between Osseo integrated devices, bone-conduction hearing aid, or the regular hearing aid.

Conductive hearing loss due to the ear canal's failure to open at birth or malformation and other dysfunctions in the middle are treatable with surgery.

Mixed Hearing Loss

Mixed hearing loss refers to both sensorineural and conductive hearing loss. For instance, long-term infections may cause damage to the ossicles and the eardrum.

Many audiologists advise patients to address the conductive condition before they proceed to the sensorineural component. The doctors also assess the client to determine the most appropriate hearing aid.

Prelingual Deafness

The inability to fully perceive sounds or acquire partial hearing before introducing speech is referred to as prelingual deafness. People with this condition were born with a congenital deformity. More often than not, individuals with this condition are born into families with parents and siblings without hearing difficulties. People with prelingual deafness are encouraged to learn sign language at an early age.

Post-lingual Deafness

People who have hearing loss have post-lingual deafness. The individual with the condition had learned to speak before they lost their hearing. Post-lingual deafness commonly occurs due to trauma, ear infections, side effects of medication, or medical conditions that cause hearing loss. The severity of the hearing loss dictates whether the patient will acquire hearing aids, learn sign language or undergo cochlea surgery.

Unilateral and bilateral deafness

Unilateral or single-sided deafness refers to suffering a hearing impairment in both ears, while the latter is a condition where you experience hearing impairment in one ear. Individuals with this condition have a hard time holding conversations since it is challenging to identify the sound source, mostly in a noisy environment.

The four levels of deafness

  1. Mild deafness

    Describes a person who can only perceive sounds between 25- 29 decibels (dB). People with this condition may have trouble understanding what you are saying, and most rely on lip-reading.

  2. Moderate deafness

    Individuals with this condition can only detect sounds of 40-69 decibels (dB). Since it is hard to grasp everything said during a conversation, individuals use a hearing aid.

  3. Severe deafness

    The person is only able to detect sounds between 70-89 (dB). People with this condition heavily rely on lip-reading and sign language to communicate effectively.

  4. Profound deafness

    This level is composed of people who can only perceive sounds below 90 (dB). Some individuals with profound deafness are unable to detect any sound at any decibel level.