Hearing loss has a lot of different causes and manifestations. It can be sudden or gradual. It can occur in one ear or both ears. It can be temporary or permanent. Before discussing causes and treatments for hearing loss, it is important to understand how hearing works.
How We Hear
There are three sections of the ear: the outer ear, middle ear and inner ear. Each section helps move sound through the process of hearing. When a sound occurs, the outer ear feeds it through the ear canal to the eardrum. The noise causes the eardrum to vibrate. This, in turn, causes three little bones inside the middle ear (malleus, incus, stapes) to move. That movement travels into the inner ear (cochlea), where it makes tiny little hairs move in a fluid. These hairs convert the movement to auditory signals, which are then transmitted to the brain to register the sound.
Causes of Hearing Loss
Hearing loss occurs when sound is blocked in any of the three areas of the ear. The most common cause of hearing loss — and one of the most preventable — is exposure to loud noises. Infections, both of the ear or elsewhere in the body, are also a major contributor to hearing loss.
- In the Outer Ear: Earwax build-up, infections that cause swelling, a growth in the ear canal, injury or birth defects can restrict hearing in the outer ear.
- In the Middle Ear: Fluid build-up is responsible for the most common infections and blockages in the middle ear. Fluid in the middle ear prevents the bones from processing sounds properly. Congential abnormalities can also affect the structure and function of the tympanic membrane and ossicles.
- In the Inner Ear: The most common reason for inner ear problems in children is genetic abnormalities of the hair cell function. Other genetic abnormalities may lead to abnormalities of the inner ear structures. Infections, some antibiotics, and neonatal problems may also lead to inner ear problems. Other more rare types of hereditary and genetic causes include CHARGE Syndrome, Connexin 26 disorder, Goldenhar Syndrome,Treacher Collins Syndrome, Usher Syndrome, Waardenburg Syndrome ).
Most causes of outer ear hearing loss can be remedied. But problems of the middle and inner ear can lead to permanent hearing loss, which is why it is important to seek medical attention quickly if you are experiencing a problem hearing.
Types of Hearing Loss
There are three types of hearing loss:
- Conductive hearing loss (CHL): Caused by conditions that block the transmission of sound through the outer ear and eardrum to the middle ear. Some possible causes of CHL include fluid in the middle ear from colds, ear infections (otitis media), perforated eardrum, benign tumors, swimmer's ear, and absence or malformation of the outer or inner ear.
- Sensorineural hearing loss (SNHL): Occurs when there is damage to the inner ear (cochlea), or to the nerve pathways from the inner ear to the brain. Most of the time, this type of hearing loss cannot be medically or surgically corrected. This is the most common type of permanent hearing loss. Some possible causes of SNHL include illnesses, drugs that are toxic to hearing, hearing loss that runs in families (heriditary or genetic), aging, head trauma, malformation of the inner ear or exposure to loud noise.
- Mixed hearing loss: Mixed hearing loss refers to children who have both conductive and sensorineural hearing loss. In other words, there may be damage in the outer or middle ear and in the inner ear (cochlea), or auditory nerve.
Hearing loss is measured in four degrees: mild, moderate, severe or profound. The degree of hearing loss drives the selection of the best form of treatment on a case-by-case basis.
Hearing Loss Treatments
The location, type and degree of hearing loss impact the choice of treatments for any hearing problem. The most common treatment options include:
- Antibiotics, decongestants and pain medication to overcome ear infections.
- Myringotomy, a piercing of the eardrum to allow for fluids to drain out of the outer ear.
- Insertion of a tube into the Eustachian tube (part of the anatomy that connects the middle ear to the back of the throat) to keep it open and allow for normal fluid drainage. This technique may be recommended for children who get frequent ear infections, or have kept fluid and pressure in the middle ear for long periods of time.
- Hearing aids.
- Surgery to correct middle ear problems such as abnormalities of the tympanic membrane, abnormal scarring and adhesions in the middle ear, or abnormailites and/or absence of middle ear bones.
If you suspect your child has a hearing loss, please contact our office and schedule an appointment. We'll conduct a physical examination as well as a hearing test to determine the type and severity of your hearing loss. We'll then recommend the best treatment.