Any hearing loss or disorder
affects our ability to communicate. It is therefore important to protect your hearing and take good care of your ears.
The ear consists of 3 parts:
- External Ear
- Middle Ear
- Inner Ear
The external ear
consists of the auricle and auditory canal. The external ear collects sound waves and directs them into the middle ear. The auricle collects sounds from every direction. The ear canal, or external auditory meatus, carries sound to the eardrum.
The middle ear
lies between the external ear and the inner ear. It consists of an air-filled cavity and includes the auditory ossicles. The middle ear consists of:
1. Ossicles in the form of three small bones:
These three bones are connected. The malleus is directly connected to the eardrum, while the stapes is connected to the inner ear. As sound waves vibrate the eardrum, it in turn moves the malleus, which transmits the vibrations via the incus to the stapes. These vibrations are then ultimately transmitted to the membrane-covered opening that leads from the middle ear to the vestibule of the inner ear, called the oval window.
2. The Eustachian tube is a narrow passage leading from the pharynx to the cavity of the middle ear, permitting the equalization of pressure on each side of the eardrum.
The inner ear
is made up of two parts:
- Cochlea for auditory portion
- Semicircular canal and otolithic organ for balance and motion
consists of hair cells, sensory cells and fluid-filled spaces. Oscillations in the middle ear set the fluid in the cochlea in motion. Hair cells in the cochlea perform the transduction of the sound waves into electrical impulses. Auditory nerve fibers transmit these electrical signals along the auditory nerve and eventually on to the brain stem for translating and processing.
Process of Hearing
- Sound travels through the external ear and impacts on the eardrum.
- Vibrations of the eardrum cause oscillations in the three bones (malleus, incus and stapes) in the middle ear.
- Vibrations set the fluid in the cochlea in motion. Tiny hair cells in the cochlea perform the transduction of the sound waves into electronic impulses.
- Auditory system transmits these electronic impulses to the brain for processing.
Causes of Hearing Loss
- Problems of the external ear include impacted earwax and ear infection.
- Problems of the middle ear include a perforated eardrum, fluid in the middle ear (Serous otitis media), chronic otitis media, otosclerosis, and poor Eustachian tube functioning.
- However, the most common cause of hearing loss is due to problems of the inner ear.
Problems of the inner ear are caused by:
- Noise induced hearing loss
- Inner ear syphilis
- Viral infection of the inner ear or nerve
- Hearing loss that runs in the family
- Diseases such as diabetes, kidney disease, high blood cholesterol, etc.
- Accidents causing damage to the inner ear
- Tumors that develop on the balance and hearing nerves
Process of Diagnosis
1. Your doctor will obtain detailed information to help identify the possible causes of your hearing loss, including:
- Duration of hearing loss
- Symptoms that go very quickly, come and go, or become worse
- Ear problems such as sound in the ear or dizziness
- Other symptoms such as facial numbness and loss of balance
- Use of medications and underlying medical conditions
- Family history of hearing loss
- Exposure to loud noise from shooting, using fire crackers, or working in factories
2. Your doctor will perform screening tests of the ears, nose, throat, nervous system, and brain function.
3. Special tests include:
- Audiogram to see how well you hear words at various volumes to determine the type of hearing loss and frequency.
- Tympanogram to see how well the middle ear is functioning.
- Evoke auditory response to test the hearing nerve.
4. If the cause of hearing loss is not found or a tumor is suspected, a CT/MRI may be required.
5. Blood test for diabetes
, kidney disease
, cholesterol, red blood cell density, syphilis, or immunity.
Treatment and Prevention
Treatment and prevention depend on the cause of the hearing loss.
- Problems of the external ear and middle ear can be treated with medications or surgery.
- Problems of the inner ear are quite complicated. Treatment depends on the cause of the hearing loss and may be ongoing. Delay in treatment may affect the results.
- You can prevent hearing loss by avoiding risk factors such as exposure to loud noise and certain medications. Seek immediate medical attention if any abnormalities are present or suspected.
Causes of Cochlear Disorder
- Bacterial or viral infection of the middle ear, inner ear or brain from meningitis, brain syphilis, herpes zoster of the ear, mumps, and rubella.
- Congenital deafness caused by maternal rubella infections or certain medications during pregnancy. An untreated hearing problem can have an effect on a child’s ability to learn spoken language. Adults with hearing loss would have communication problems at work, which may result in them losing their jobs.
Treatment of Patients with Hearing Loss
- Otitis or otitis media can be treated with surgical procedures.
- Cochlear disorder:
2.1 Mild symptoms that have been present for less than 1 month can be treated with oral medications.
2.2 In the case of mild hearing loss, a hearing aid inserted into the ear or pushed deeper into the ear canal can help with making sounds stronger.
2.3 In the case of severe hearing loss, in which a hearing aid cannot help, a cochlear implant may be an option. This is a complicated procedure. Performing a cochlear implant requires the cooperation of a team of surgeons and speech therapists.