How We Hear
In the ear, there are three sections: the outer ear, middle ear and inner ear. Each part of the ear helps move sound through the process of hearing. From the first instance of sound, the outer ear feeds the sensations through the ear canal to the eardrum.
The noise causes the eardrum to vibrate. The vibrations cause 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 sent to the brain to register the sound.
Causes of Hearing Loss
When sound is blocked in any of the three areas of the ear, hearing loss occurs. Being exposed to loud noises is one of the most common causes of hearing loss and one of the most preventable. Infections are also a major contributor to hearing loss, whether they happen in the ear or somewhere else in the body.
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.
Middle Ear
Most common infections and blockages in the middle ear are a result of fluid build-up. Fluid in the middle ear keeps the bones from processing sounds properly. Tumors, both benign and malignant, can also result in hearing loss in the middle ear.
Inner Ear
The natural process of aging diminishes hearing from damage to the cochlea (mechanism for converting sound vibrations to brain signals), vestibular labyrinth (which regulates balance), or the acoustic nerve (nerve that sends sound signals to the brain). Additionally, inner ear infections, Meniere's disease and other nerve-related problems contribute to hearing loss in the inner ear.
Other causes of hearing loss include:
- Presbycusis: As an age-related hearing loss, presbycusis manifests itself by having difficulty hearing in noisy places, having trouble understanding what people are saying or not registering softer sounds.
- Heredity and Genetic Causes: There is a wide variety of diseases and syndromes that are either genetic or hereditary that can cause hearing loss. Some, like rubella (German measles) occur when a pregnant mother has the disease, which causes hearing loss in the baby. Other, rarer types of hereditary and genetic causes include CHARGE Syndrome, Connexin 26 disorder, Goldenhar Syndrome,Treacher Collins Syndrome, Usher Syndrome, Waardenburg Syndrome and otosclerosis (growth of spongy bone tissue in the middle ear).
While most causes of outer ear hearing loss can be remedied, issues in the middle and inner ear can lead to permanent hearing loss. If you are having difficulty hearing, seek medical attention quickly.
Types of Hearing Loss
There are four types of hearing loss:
1. Conductive hearing loss
Caused by conditions that block the transmission of sound through the outer ear and eardrum to the middle ear.
2. Sensorineural hearing loss
Inner ear damage that occurs as part of the natural process of aging.
3. Mixed hearing loss
Mixed hearing loss is when someone has both conductive and sensorineural hearing loss. Most people experience more than one type of hearing loss.
4. Central hearing loss
When the central nervous system fails to send a readable signal to the brain it becomes a central auditory processing disorder. People with central hearing loss generally can hear all sounds, but can't separate or process them.
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 influences the choice of treatments for any hearing problem. The most common treatment options include:
- Antibiotics, decongestants and pain medication to overcome ear infections.
- Myringotomy, piercing 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 people who get frequent ear infections.
- Hearing aids.
- Surgery to remove benign or malignant tumors or correct bone- or nerve-related problems.
If you undergo any sudden or prolonged hearing loss, along with dizziness, fever or pain, please contact our office right away and schedule an appointment with one of our otolaryngologists. During your appointment, we'll conduct a physical examination and a hearing test to determine the type and severity of your hearing loss. We'll then recommend the best treatment.