Hearing Loss Types

The ear is made up of three parts: the outer ear, the middle ear, and the inner ear. The outer ear refers to the entrance of the ear canal up to the eardrum. The middle ear refers to the space between the eardrum and the cochlea, and the inner ear refers to the part of the ear that holds the hearing organ (a.k.a. cochlea) including the auditory nerve. 

There are also generally considered to be three types of hearing loss: sensorineural, conductive, and mixed. Sensorineural happens when important mechanisms in your inner ear become damaged. Conductive happens when sound is blocked from passing through your outer and middle ear, so it can’t get to your inner ear. Mixed happens when you have a mix of both sensorineural and conductive symptoms.

The mechanisms for receiving and processing soundwaves sit in your inner ear. It contains hair cells, special fluid that helps process sound, and the auditory nerve. The nerve is what connects to the  central hearing system in the brain. 

When you have sensorineural hearing loss, it is because one or more of these mechanisms become damaged. Usually it is a loss of the inner ear hair cells, either due to aging, an underlying health condition, or exposure to loud noise. When you lose these hair cells, your hearing becomes less sensitive. The more you lose, the less sensitive your hearing becomes. Unfortunately, there is no way to restore these sensory hair cells after they are lost.

Sensorineural hearing loss is usually permanent, and is treated with hearing aids to amplify and process the sound for you.

In order for your inner ear hair cells and auditory nerve to process sound, the sound waves have to travel through your outer and middle ear to the inner ear, there your inner ear hair cells feed the signal to your brain through the auditory nerve.

When you have conductive hearing loss, it is because your outer or middle ear is blocked. The blockage restricts or prevents sound waves from getting to your inner ear. The blockage can be partial or total, and the severity of the blockage will affect the severity of your hearing loss. Conductive loss can be temporary or permanent, depending on the exact cause of the blockage. 

Conductive hearing loss is caused by infections, inflammation, protrusions, and other health conditions. If the underlying health condition that causes the blockage can be treated, your hearing may return to normal. 

The third type of hearing loss is called mixed hearing loss. This happens when you have a mix of both sensorineural and conductive. 

For example, you can have sensorineural hearing loss due to being exposed to loud noise. You can then also have excessive earwax that blocks your canals, and further reduces your hearing. 

When you have mixed hearing loss you will show the signs and symptoms of both types. You will also likely need to receive treatments designed for both. Treating the conductive loss will help restore the hearing you lost due to the blockage. However, it won’t return the sensorineural hearing that you lost. Your new ‘normal’ level of hearing will be set according to the state of your inner ear health.

Aside from the three types of hearing loss, there are other hearing disorders and ways of classifying your hearing. 

Unilateral and bilateral hearing loss refers to the ear, or ears, in which you have hearing loss. Unilateral means you have loss only in one ear, while your other ear is fine. Bilateral hearing loss means you have loss in both ears. When you have bilateral hearing loss, you may have different levels of hearing loss in each ear.

Neither unilateral or bilateral hearing loss refer to the type, cause, symptoms, or treatment of hearing loss. You can have all three types in one or both ears. All it refers to is a categorization of whether it affects one or both ears. 

Tinnitus is a condition where you experience some kind of sound that is not coming from any external source. The telltale sign of tinnitus is typically a ringing, hissing or buzzing sound. It is a common hearing disorder for adults to experience, and is often tied with sensorineural hearing loss. 

You can decrease the severity of symptoms through special treatments including hearing aids. They help you mask tinnitus so you don’t notice it as much.

Auditory Neuropathy Spectrum Disorder (ANSD) is a condition that affects your hearing, but does not involve hearing loss that originates from your ear. It happens when sound waves successfully travel through your outer and middle ear, and are received by your inner ear. But there is an issue with the signal sent between the auditory nerve and the brain. 

When you have ANSD, you may have your hearing tested and show no hearing loss at all. You may also show mild to severe hearing loss. Someone with ANSD typically has an issue with understanding and processing speech. They may be able to hear general sounds just fine, but cannot recognize nuance within the sound — such as specific words as someone talks.

ANSD is a hearing disorder that cannot be treated like normal hearing loss. This is because the usual mechanisms for hearing are not affected. There is no blockage in your ear canal that would prevent sound from reaching your inner ear, and your inner ear is able to receive sound like normal.

It is purely an issue with how the sound is processed into a signal and sent to your brain. There is no consensus treatment for someone with ANSD, but you would need to see a specialist.

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