There are three basic types of hearing loss and these are:
- Sensorineural Hearing Loss
The vast majority of people with hearing loss have sensorineural hearing loss. This occurs when there is a problem with the sensory (hair cells) and/or neural structures (nerves) in the inner ear (cochlea). Most often, sensorineural hearing loss involves damage to the tiny hair cells that are activated by sound waves to vibrate and release chemical messengers that stimulate the auditory nerve. The auditory nerve is made up of many nerve fibers that then carry signals to the brain that are interpreted as sound. While sensorineural hearing loss usually involves damage to the tiny hair cells, it also can result from damage to the auditory nerve.
A sensorineural hearing loss reduces the intensity of sound. But a sensorineural hearing loss also can distort what is heard—even when the sounds are loud enough. That is why people with sensorineural hearing loss often struggle to hear words clearly—particularly certain spoken consonant sounds and when in noisy environments.
Most sensorineural hearing loss cannot be reversed with medical treatment and is typically described as an irreversible, permanent condition. Nevertheless, research into a cure continues.
The good news is that once any underlying medical conditions have been ruled out or addressed, most people with sensorineural hearing loss can benefit from hearing aids.
Ninety-one percent of people who purchased hearing aids in the last year say they’re satisfied, in fact. And 90 percent say they’d recommend getting hearing aids to family members and friends.
Some of the potential causes of sensorineural hearing loss include:
- Exposure to loud noise
- Medicines that damage the ear (ototoxic)
- Illnesses, such as meningitis, measles and certain autoimmune disorders, among others
- Genetics—that is, hearing loss runs in the family
- Trauma to the head
- Structural malformation of the inner ear
- Conductive Hearing Loss
Conductive hearing loss is mechanical in nature. That means that something—a physical condition or disease—is stopping sound from being conducted from the outer or middle ear to the inner ear, where nerves are stimulated to carry sound to the brain.
Often, the cause of conductive hearing loss can be identified and treated. Medical treatment of conductive hearing loss often allows for partial or complete improvement in hearing. Then, hearing aids are usually helpful in compensating for any remaining hearing loss.
Potential causes of conductive hearing loss include:
- Wax buildup
- Fluid in the middle ear due to colds or allergies
- Fluid in the middle ear due to poor eustachian tube function (The eustachian tube drains fluid from the middle ear and ventilates it to regulate air pressure there.)
- Ear infection
- A foreign object lodged in the ear
- A ruptured eardrum (also called a perforated eardrum or a tympanic membrane perforation), which means there is a tear in the membrane that separates the outer ear from the middle ear
- Structural malformation of parts of the ear
- Trauma to the ear
- In rare cases, tumors
- Mixed Hearing Loss
A mixed hearing loss means there is a sensorineural hearing loss along with a conductive hearing loss component. In addition to some irreversible hearing loss caused by a problem with the inner ear, there also is an issue with the outer or middle ear, which makes the hearing loss worse. But it may be possible to successfully treat the conductive hearing loss, as explained above. Following treatment, the individual also may benefit from hearing aids to help manage the remaining sensorineural hearing loss.