Conductive vs. Sensorineural Hearing Loss: What's the Difference?
When it comes to disabilities, hearing loss is one of the most widespread disabilities in the United States. Millions of people suffer from this condition, representing a huge field of study in the medical industry. One of the reasons for the massive reach of this disability is that no one is immune to it. While genetic factors may make a person more inclined to acquire or develop hearing loss, all people share a high propensity to either develop it or acquire it throughout life.
Hearing loss itself can have a host of different origins. However, it is typically defined as three major types: Sensorineural, conductive, and then a mix of the two. Before we look at what life with these conditions may be like and what options you have, let's first take a closer look at the difference between conductive and sensorineural hearing loss.
What Is Hearing Loss?
Hearing loss itself declines a person’s natural ability to hear certain frequencies at their natural decibel level. One of the reasons why hearing loss is so widespread is that most people use their ears fairly consistently. This concept may be so basic that it doesn't seem novel, but it’s something that many people don’t think about -- but a person's ears are typically always working.
This consistent use and heavy exposure to the elements means that the probability of a person developing some kind of hearing issue is high. Even if it’s simply that as a person ages, their chances of acquiring or developing hearing loss become substantial.
Developing hearing loss itself can come from aging, chronic exposure to loud noises, or even traumatic events. At a normal hearing level, a person’s decibel threshold is naturally very low. This threshold is the point at which a sound wave has enough force to be recognized by the sensing organ of the ear.
Every sound wave travels at a certain frequency and with a natural amount of force or power. That force or power can be realized in daily life; like when visiting the zoo, you can notice the quiet chirping of a bird in a tree overhead being overpowered by the throaty roar of a bear or a lion. The sounds are emitted not just at a specific frequency but with a specific amount of power -- and that power is measured in decibels.
As a person’s hearing depreciates and decreases, their natural decibel threshold increases. This means that their natural ability to hear certain sounds is lost unless they are boosted to a higher decibel.
Degrees of Hearing Loss
No matter the type of hearing loss, the results are the same -- less ability to recognize natural sounds at their natural decibel range. However, certain types of hearing loss can be indicative of a more severe degree of hearing loss.
The American Speech-Language-Hearing-Association defines hearing loss into seven degrees of hearing loss:
- Moderately Severe
Each of these degrees correlates to a steadily increasing decibel threshold that starts at --10 to 15 decibels for normal hearing and goes all the way to 91 and above for profound hearing.
Three Types of Hearing Loss
When a person acquires or develops hearing loss, they can get different types of hearing loss. There isn’t one succinct origin for this disability, and it can have a single or multiple causes. As stated earlier, those three types of hearing loss most often experienced by individuals are conductive, sensorineural, and mixed. Now it’s time to take a closer look at each.
Conductive Hearing Loss
The best way to understand conductive hearing loss is to talk about the anatomy of the ear. This is only the case because conductive hearing loss takes place when something is physically blocking or manipulating this anatomy to not work at optimum levels.
Your ear is composed of three compartments, the outer ear, the middle ear, and the inner ear. These three compartments work in tandem to send a signal to interpret sound by turning it into an electric signal that goes to the brain, where it is translated as the sound we experience.
The outer ear itself is composed of an auricle, which is the outer part of the ear that is easily visible. This structure protects the rest of the ear, and the opening of the ear canal can be found here.
As you move down the ear, you come to the middle ear compartment. This compartment is separated from the outer ear by what is known as the tympanic membrane -- or more commonly - the eardrum. The inner ear cavity houses three tiny, fundamental bones: the malleus, incus, and stapes.
When sound travels through the outer ear, it interacts with the tympanic membrane down the ear canal. It creates a vibration that is passed onto the incus, malleus, and stapes. This energy vibrates the bones in specific ways that translate to the inner ear.
In the inner ear, we find a snail-like, fluid-filled structure called the cochlea. This is considered the nerve center of the ear. At this location, those vibrations from the middle ear are taken and transposed into electrical impulses that then travel through the hearing or auditory nerve to the brain.
When any part of this process is interpreted due to a blockage, pressure, or any kind of unnatural barrier -- this is what we call conductive hearing loss. A sound wave is meant to “conduct” through the entering of the three compartments, interacting at every juncture in a way that sends the proper signals to the brain. When that is blocked, or impaired a person experiences a loss of hearing.
This can be something as minimal as a build-up of earwax that makes sounds feel distant or muffled or something as serious as trauma causing profound hearing loss. Conductive hearing loss can also result from autoimmune disorders attacking the inner ear cells, causing inflammation that can disrupt the hearing.
Treatment for conductive hearing loss can be comprehensive and is dependent on the cause of the conductive hearing loss itself. As stated before, if someone is experiencing slight to mild hearing impairment due to ear wax build-up -- then an adequate solution for this problem would be a thorough ear cleaning procedure.
However, surgery might be necessary if someone has a foreign object lodged from a traumatic event in their ear. Hearing aids are one of the most common forms of treatment for most hearing loss and can, depending on the diagnosis, be the best form of treatment for conductive hearing loss, especially if non-correctable hearing loss has taken place.
Sensorineural Hearing Loss
Sensorineural hearing loss, or SNHL, deals specifically with the inner ear. This type of hearing loss refers to issues or problems in the neurological function of the hearing process. This can either develop due to genetic factors or occur after some kind of damage or trauma to the inner ear. Illnesses like autoimmune disorders can cause damage to the inner ear which can lead to sensorineural hearing loss. Also, medications or chemical toxins can play a role in the development of sensorineural hearing loss.
Sensorineural hearing loss is one of the most common types of hearing loss that accounts for permanent or complete deafness. This kind of hearing loss typically presents as more serious than conductive, although people with sensorineural issues can notice only small impairments.
This type of hearing loss can present as gradual or sudden and ranges from mild to profound. SNHL can be treated in various ways depending on the severity or cause of the hearing loss. Hearing aids are one of the most common forms of hearing loss treatment and can be prescribed for people experiencing SNHL. Inner ear implants are also another form of treatment for more severe cases that hearing aids would be ineffective against. Corticosteroids may be used to help inflammation of the inner ear as well.
If you are suspicious that you may be experiencing hearing loss, it’s important that you go to your primary care provider to try and understand what is happening. The physical symptoms for conductive hearing loss and sensorineural are similar, and typically specific hearing tests are needed to evaluate the type of hearing loss you may have.
“As an ENT specialist, I enthusiastically recommend Audien hearing aids for my patients.”
- Drew Sutton, MD, Board-Certified Otolaryngologist.
The benefit of early diagnosis and treatment cannot be overstated. This can help you understand what level of hearing treatment you require. We are passionate about providing an affordable hearing aid option for those who are suffering from hearing loss.
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Drew Sutton M.D.
Drew Sutton, MD is a board-certified otolaryngologist. He has extensive experience and training in sinus and respiratory diseases, ear and skull base surgery, and pulmonary disorders. He has served as a Clinical Instructor at Grady Hospital Emory University for more than 12 years.