30 Oct Types of Hearing Loss
Below is a brief explanation of each of the three basic types of hearing loss:
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.
According to research by The Better Hearing Institute, 91% of people who purchased hearing aids in the last year say they’re satisfied. And 90% say they’d recommend getting hearing aids to family members and friends. Hearing aids are currently the only real treatment option.
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
- 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.
What about presbycusis, noise-induced hearing loss, and tinnitus?
Presbycusis simply means age-related hearing loss. Typically, presbycusis comes on gradually and equally in both ears. In most cases, it’s the result of changes in the ear that happen as people get older.
Often, presbycusis involves damage to the inner ear, making it a sensorineural hearing loss. Cardiovascular disease, diabetes, other health conditions common with aging, and ototoxic medications that can damage the inner ear all can contribute to presbycusis. In addition to what aging does to the inner ear, common age-related changes to the brain can make it more difficult to understand conversations in challenging listening situations such as in restaurants or when several people are talking at once.
Noise-induced Hearing Loss
Noise-induced hearing loss is a type of sensorineural hearing loss. It’s caused by damage to the delicate hair cells in the inner ear that vibrate in response to sound waves. Just as we can overload an electrical circuit, we can overload these hair cells with too much noise or sounds that are too loud. The hair cells that enable us to clearly hear higher-frequency sounds tend to go first.
Although noise-induced hearing loss is largely preventable, it’s a significant societal problem due to so much noise in the world around us.
Any sounds at or above 85 decibels for a prolonged period of time can be unsafe to a person’s hearing. (The intensity of sound is measured in decibels.) To put that in perspective, most heavy city traffic and school cafeterias are at about 85 decibels, and fireworks are in the 140-to-165 decibels range. It’s also important to realize that something like the single bang of a firecracker at close range can permanently damage hearing in an instant.
Because noise-induced hearing loss is so common, attributing gradual hearing loss over time strictly to aging can be somewhat misleading. In middle-aged and older people, it’s often difficult to distinguish what percentage of a sensorineural hearing loss is attributable to aging and what percentage is the result of repeated exposure to noise.
Often called “ringing in the ears,” tinnitus is the perception of a sound in a person’s ears or head that has no external source. Many people with tinnitus experience a ringing, humming, buzzing, or chirping sound. Others even perceive singing or music. Experts believe that neural hyperactivity—that is, overstimulation of the nerves—leads to this perception of sound.
Often, tinnitus is the by-product of noise exposure, although it can be caused by other things as well. Tinnitus is almost always accompanied by hearing loss and is considered a symptom of hearing loss.
Many people can manage the annoyance associated with tinnitus with hearing aids. A good number of high-tech hearing devices now include integrated “sound therapy” specifically designed to offer relief from tinnitus.
We strongly encourage people who suspect hearing loss to book an appointment with their hearing care provider. Addressing hearing loss can have a tremendously positive impact on a person’s everyday life.