There are 3 types of hearing loss: 1. Sensorineural Hearing Loss 2. Conductive Hearing Loss 3. Mixed Hearing Loss
As an audiologist, I spend all day, every day testing and treating individuals who have hearing loss. Nearly 50 million people in the United States alone have hearing loss. Of these 50 million cases, there’s only three general classifications, but many conditions that can cause each type. Some of these are common, some of these are not so common. Nonetheless, I want to share with you the three classifications of hearing loss, and some potential causes of each type.
The first type of hearing loss is sensorineural. Despite what the name says, most of the time, it isn’t the auditory nerve itself that has the problem, but it’s the little tiny hair cells that are inside your hearing organ, otherwise known as your cochlea. These hair cells flex and move when sound comes into the ear. Their movement sends a signal through the auditory nerve to the brain, causing you to hear. If these hair cells don’t work right, you’ll have a hearing loss.
Some of the most important causes of sensorineural hearing loss are noise exposure and age. If these hair cells sustain a lot of damage from excessive noise exposure, either from impact sounds like a firecracker, or long-duration sounds like a motorcycle engine, you could sustain a sensorineural hearing loss. The good news is that this type of hearing loss, is preventable. Just wear hearing protection. On the other hand, if age is the culprit, there’s little you can do to prevent this type of hearing loss. Nearly everyone will develop this type of hearing loss if they live long enough.
Sensorineural hearing loss is treatable by hearing aids, when the outer hair cells are the ones that are damaged. If too many inner hair cells are damaged, it prevents the proper transmission of sound to the brain, and will limit the hearing aid benefit. Other less common causes of sensorineural hearing loss are sudden hearing losses, and acoustic neuromas, or tumors. Both of these generally occur in only one ear at a time. If you ever experience hearing loss in only one ear, get to your doctor immediately.
Sudden hearing losses are generally caused by a virus attacking the hair cells of your cochlea that we just talked about. Treatment includes steroids, but success with treatment depends on how quickly you receive it. Acoustic neuroma, or tumor, can also give you a sudden hearing loss, but not always. This occurs when a tumor is growing on your auditory nerve and blocks sound from making it to your brain. Obviously, anytime a tumor is involved, it becomes more serious.
The second type is a conductive hearing loss, or mechanical hearing loss. A conductive hearing loss is caused by something preventing the proper transmission of sound to the cochlea. In this case, there is nothing wrong with your cochlea, or auditory nerve – it’s just that the sound can’t make it from your outer ear all the way to your inner ear. Sound has to travel through the ear canal and vibrate the ear drum, which causes the ossicles, otherwise known as the hearing bones, to move. Then, they move the fluid inside the cochlea to cause that neural impulse. If any link in that chain has a problem doing its job, you’ll have a conductive hearing loss.
There are many causes of conductive hearing loss. Some of the most common are earwax, which block the vibration of sound, an eardrum with a hole in it, fluid behind the ear drum, disconnected ossicles, or even fused ossicles. A simple hearing test is able to identify exactly where the problem is. Conductive hearing losses often require medical intervention and sometimes require surgery to correct.
The third type is a mixed hearing loss. This is when there’s a component of a sensorineural hearing loss, combined with a conductive hearing loss. This type of hearing loss is not common and requires multiple types of treatment.