Imagine you’re sitting in a crowded restaurant, and someone is trying to talk to you. However, the noise around you makes it difficult to understand what they’re saying. The words you do manage to hear are all mixed up and don’t make any sense. This makes it harder for you to have conversations in noisy places and, as a result, you start avoiding social situations.
But here’s the thing: your hearing is not actually getting worse, because you can hear just fine when it’s quiet. The problem lies in the clarity of the sounds you hear, not their volume. Many people who come to our office have experienced the same thing, although not everyone.
The reason why hearing difficulties can vary from person to person is because there are different types of hearing loss. In this article, we’ll talk about these various forms of hearing loss and what causes them. Understanding these different types can help you make sense of the hearing challenges you’re facing.
The Process of Hearing
To better understand the different types of hearing loss and their causes, you must know what happens during the process of hearing. It is essentially a four-step process.
Sound waves enter the outer ear
As sound hits the outer ear, it filters and amplifies sound waves, sending them down the ear canal to the eardrum, or tympanic membrane, which begins to vibrate as soon as sound waves hit it.
Sound moves through the middle ear
Attached to the interior side of the eardrum is a chain of three small bones (the smallest in your body), known as the ossicles. When the eardrum vibrates in response to sound waves, these bones function like a lever, amplifying the sound energy as it moves from the relatively large tympanic membrane to the relatively small oval window.
Sound moves through the inner ear (the cochlea)
As the amplified sound vibrations push on the oval window, they create pressure waves in the fluid-filled cochlea, where they are transformed into electrical energy by cells known as hair cells (stereocilia).
Your brain interprets the signal
Once sound is converted to electrical signals in the cochlea, these signals travel via auditory nerve pathways to the auditory cortex and other parts of the brain that regulate awareness and sensory perception, which interpret or give meaning to the sound signals.
Three Types of Hearing Loss: Symptoms, Causes, and Treatment Options
The type of hearing loss you have depends on where damage is found along the hearing pathway and what structures have been damaged. The severity of your hearing loss will depend on how extensive that damage is.
There are three basic types of hearing loss, with different symptoms and causes to consider.
Conductive Hearing Loss
As its label suggests, this type of hearing loss relates to how sound is “conducted” or moved through the hearing pathway. Conductive hearing loss (CHL) occurs when sounds are limited or prevented from passing through the outer and/or middle ear, essentially blocking the passage of sound waves.
With conductive hearing loss, soft sounds may go unheard and louder sounds will be muffled. Other symptoms associated with this form of hearing loss include a feeling of fullness or pressure in the ears, tinnitus (ringing in the ears), and some issues with sound clarity in a noisy environment.
Conductive hearing loss can be caused by:
- Fluid in the middle ear
- Middle ear infection, or otitis media
- Poor Eustachian tube function
- A hole (perforation) in the eardrum
- Benign tumors
- Impacted earwax, or cerumen
- Infection in the ear canal, called external
- otitis (swimmer’s ear)
- An object stuck in the ear canal
- Malformation of the outer or middle ear
Treatment options for CHL may include the removal of earwax, tumors, or objects in the ear canal, medications to treat inflammation or infection, the insertion of tubes in the Eustachian tube, and/or surgical procedures.
Sensorineural Hearing Loss
Sensorineural hearing loss, or SNHL, involves damage to the structures or components of the inner ear, which typically involves the destruction of the super delicate stereocilia, but can also involve issues with the nerve pathways from your inner ear to your brain.
Presbycusis, or age-related hearing loss, is included in the SNHL category and is the most common form of permanent hearing loss.
SNHL symptoms can include issues with loudness, but challenges with sound clarity are more common, especially in environments with a lot of background noise. Other symptoms associated with this type of hearing loss include tinnitus, balance disorders, difficulty distinguishing between different speech sounds (like “f,” “s,” and “th”), and struggling to understand higher-pitched voices (like those of women and children).
The common causes of SNHL include:
- Diseases or illnesses
- The use of ototoxic drugs or medications
- Genetics
- Aging
- Head trauma (traumatic brain injury, or TBI)
- Malformation of the inner ear
- Ongoing exposure to loud noise
- (noise-induced hearing loss, or NIHL)
In most cases, medications and/or surgery are unable to treat SNHL. Hearing aids are the most common form of treatment, but other treatments may include bone-conduction hearing devices and cochlear implants.
Mixed Hearing Loss
Less common than either of the other two types, accounting for less than 2 percent of total hearing loss cases, mixed hearing loss includes symptoms and causes of both sensorineural hearing loss and conductive hearing loss. Like the other two types, it can either be bilateral (affecting both ears) or unilateral (affecting only one ear).
There are three instances in which mixed hearing loss may occur:
- An individual with sensorineural hearing loss is subjected to an injury, trauma, blockage,
- or illness that leads to the addition of conductive hearing loss
- Someone who already has conductive hearing loss sustains damage to the inner ear due to aging, NIHL,
- or some other cause that leads to the addition of sensorineural hearing loss
- A blast injury or other trauma causes simultaneous sensorineural and conductive hearing loss
When examining mixed hearing loss symptoms, it’s best to attribute them to their respective types. Generally, SNHL symptoms involve sensory or clarity issues while CHL symptoms tend to be more physical.
Because it is a combination of both hearing loss types, treatment options will include a combination of treatment options targeted at each of the other two types of hearing loss.
What Type of Hearing Loss Are You Struggling With?
Regardless of which of the three types of hearing loss you are struggling with, when left untreated hearing loss can cause several “side effect” symptoms, like irritability, stress, frustration, depression, mental exhaustion, and isolation. These can lead to poor performance at work and strained relationships, and they can also increase your rate of cognitive decline and risk of developing balance disorders.
If you are experiencing symptoms of any of the three types of hearing loss, a comprehensive hearing assessment with an audiologist is the first step toward better hearing, as well as preventing these negative mental and physical health consequences for a better quality of life. Just use the adjacent form to schedule your hearing test today!
