Types Of Hearing Loss
Hearing loss occurs when there is decreased sensitivity to the sounds within the threshold of normal hearing (25dB or better in both ears). It can affect one or both ears.
The world health organization (WHO) estimates that 360 million people, over 5% of the world’s population, have disabling hearing loss, with the majority of them living in low/middle-income countries. In Egypt alone, 5 million people suffer from hearing loss.
Out of the 369 million, 328 million are adults and 32 million are children. 25% of hearing loss cases starts during childhood. The numbers grows dramatically with age; almost 1 in 3 adults over 65 have hearing impairment.
Hearing loss can be described into three basic types, depending on which part of the auditory system is damaged:
- Conductive hearing loss
Hearing loss due to a problem that stops sounds from getting through the outer or middle ear. The problem affects the ear canal, eardrum, or middle ear and its bones. Conductive hearing loss can result from fluid in the middle ear from colds, ear canal infection, allergies, poor Eustachian tube function, perforated eardrum, presence of a foreign body,benign tumors, impacted earwax , or swimmer's Ear (otitis ecxterna). It can also be due to malformation of the outer ear, ear canal, or middle ear.
- Sensorineural hearing loss (SNHL)
Sensorineural hearing loss occurs due to problems of the inner ear and how the hearing nerves work. It is known as nerve-related hearing loss. It can be caused by Illnesses Drugs toxic to hearing, genetic hearing loss, aging, trauma to the head, malformation of the inner ear, and exposure to loud noises.
- Mixed hearing loss
Mixed hearing loss occurs when both conductive and sensorineural hearing loss are present. There may be problems with the outer or middle ear, as well as the inner ear (cochlea) or auditory nerve.
Hearing loss can vary from mild to profound, depending on its degree:
Soft sounds are hard to hear.
- Moderate hearing loss
Almost no speech can be heard by the person affected by hearing loss when another person is talking at a normal level.
- Severe hearing loss
No speech said at a normal level can be heard. The person can only hear some loud noises.
- Profound hearing loss
Only very loud sounds can be heard.
An audiogram is a graphical display of a person’s hearing ability, and can help a patient understand his/her degree of hearing loss. For more information,
click here.
Hearing loss can also be described as:
- Unilateral
Hearing loss is in one ear.
- Bilateral
Hearing loss is in both ears.
- Pre-lingual
Hearing loss occurred before a person learned to talk (pre-lingual) or
- Post-lingual
It happened after a person learned to talk.
- Symmetrical or Asymmetrical
Symmetrical hearing loss is the equal in both ears, however if it is different then it is asymmetrical hearing loss.
- Progressive or Sudden
Progressive Hearing loss gets worse over time, while Sudden hearing loss happens quickly.
- Fluctuating or Stable
Hearing loss gets either better or worse over time (fluctuating) or stays the same over time (stable).
- Congenital or Delayed/Acquired Onset
Hearing loss is there at birth (congenital) or appears later in life (acquired or delayed onset).