Types of Hearing Loss, Risks and Prevention
There are three main types of hearing loss; sensorineural, conductive and mixed. Sensorineural is where there is a problem occurring in either the auditory nerve or inner ear, which is what delivers sound to the brain. Conductive is where the sound isn’t reaching the inner ear, normally because of an obstruction or trauma. Mixed is a combination of the two.
Sensorineural hearing loss
This is the most common type of hearing loss, it’s a permanent loss of hearing that occurs when there is either damage to the auditory nerve that weakens or prevents the transfer of nerve signals that are directed to the brain or damage to the tiny hair-like cells of the inner ear. These signals carry important information regarding the loudness and clarity of sounds.
Sometimes a child can be born with sensorineural hearing loss, it is most commonly down to a genetic syndrome or from an infection passed from mother to fetus inside the womb, such as toxoplasmosis, herpes or rubella. It’s more typical to see sensorineural hearing loss developing later in life, which is caused by a variety of triggers. The causes include:
- Presbycusis, normal aging
- Extended periods of exposure to extremely loud noises
- Cardiovascular diseases
- Traumatic injuries that have caused damage to the inner ear or auditory nerve
- Autoimmune diseases
- Infections such as meningitis, scarlet fever, mumps and measles
- Meniere's disease
- Having a side effect from medicines
- Acoustic neuroma, or growths in the ear
Both loudness and the clarity of sounds are affected by the symptoms of sensorineural hearing loss. For a lot of people, they will have high-frequency hearing loss, which leads to the following symptoms:
- Hearing speech from others as mumbled or slurred. You may feel like you can hear but not understand what they’re saying
- You may have difficulty following a conversation where there are more than two people conversing at the same time
- Problems in noisy environments like convention centers, malls or train stations.
- More difficulty with women’s or children’s voices
- Difficulty hearing high pitched sounds
- Problems identifying sounds such as th or s.
- Some noises seem too quiet or loud
- Feeling off-balanced
- Feeling dizzy
- Being able to hear people speak but not clearly
There is no surgical or medical way of repairing the auditory nerve or hair-like cells in the inner ear if they have become damaged. However, sensorineural hearing loss can be easily treated by visiting an audiologist who can help with hearing aids or cochlear implants.
Conductive hearing loss
Conductive hearing loss is less common, it happens when there is an obstruction or damage to the outer or middle ear that prevents sound from being conducted to the inner ear.
Conductive hearing loss can also be temporary or permanent, depending on what has caused it.
The causes of conductive hearing loss can be determined by which part of the ear they affect, the outer or middle ear.
The outer ear includes:
- Narrowing of the ear canal
- Otitis externa
The middle ear includes:
- A breach in the eardrum caused by injury, ear infections or extreme air pressure changes
- Ear infection, the build-up of fluid
- Blockages in the eustachian tube, this connects the middle ear to the back of the nose and throat
- Ossicular chain discontinuity
Someone who primarily has conductive hearing loss will have difficulty with the loudness of sounds but not clarity. You will find that these people will turn the volume up on thing like the radio or tv to improve what they can hear. If you start to experience this kind of hearing loss, speak to your audiologist. Other symptoms include:
- Can hear better in one ear than the other
- Pain in your ears
- Pressure in ears
- Difficulty hearing on the telephone
- Hearing your own voice differently
There are some medical or surgical treatments that can improve hearing for those with conductive hearing loss. Such as ear infections, obstructions, growths and wax impaction that are often temporary. Conductive hearing loss that is permanent may be treated by an audiologist with hearing aids or bone-anchored implantable devices.
Mixed hearing loss
Mixed hearing loss is a combination of sensorineural and conductive hearing loss.
Mixed hearing can happen over time and be caused by trauma. Someone who has long-standing conductive hearing loss might start to experience age-related hearing loss too.
The symptoms of mixed hearing loss are a combination of both sensorineural and conductive, and may include difficulty hearing in noisy situations and pressure or pain in the ear.
Treatment options for mixed hearing loss will be affected if the loss is more sensorineural or conductive. Your audiologist will be able to work with you to find the best solution.
If you think that you may be experiencing hearing loss speak to our audiologists to learn more about Audiological Services of San Francisco at 415-346-6886.