The 4 Levels Of Hearing Loss
December 14, 2020

Hearing loss affects more than 1 in 6 of every American today. That equals approximately 48 million Americans with some degree of hearing loss currently, and while that may seem a lot, there are options available for many suffering. 


Hearing loss can be subtle, such as when the TV sounds too soft or challenging to hear a phone conversation. Other items can be more obvious, such as when you can’t hear loud noises such as heavy machinery explosive noise like a gun firing.

 Image of individual experiencing hearing loss

 

Sound familiar? These are just a few of the symptoms of hearing loss, and if you or a loved one are concerned about your hearing, consult your primary care physician to discuss symptoms and get a possible diagnosis.

How Hearing Works

We hear that sound travels as an energy wave to the outer ear and passes through the middle ear and the inner ear, where the energy creates vibrations within the ear that transmit through the auditory nerve to the brain where the sound is made. 

For many that suffer from one degree of hearing loss or other, the process of sound traveling through the auditory canal can be impacted, or there is damage to the inner ear that affects the process. 

As we hear in stereo, the sound is heard simultaneously in both ears, and blockage or damage to one ear can disrupt overall hearing quality. We hear in stereo because it allows us to determine the direction the sound was made, the distance we are from the source, and aids in the clarity of the sound. Damage to one ear can impact any of these functions with stereophonic hearing as well.

There are plenty of causes for hearing loss, from heredity and congenital disabilities to trauma, disease, and aging that will be examined further in this article. 

What are the various hearing loss levels, how does hearing loss happen, can it be done for hearing loss sufferers? 

Before discussing the amplification process of how hearing loss occurs, we need to understand hearing loss levels and hearing loss types.

What Is Hearing Loss

Hearing loss is defined as when sound is no longer able to be decipherable. 

Symptoms can range from muffled sounds and speech that may be difficult to understand. 

There can be a sensation of stuffiness or a feeling of pressure, the balance may be affected in more severe cases, and pain can be another symptom. Regular speech patterns may seem as if the speaker is whispering or mumbling, especially in a crowded, noisy setting. 

Other symptoms of hearing loss may be constant ringing in the ears, known as tinnitus. Telephone calls are difficult to distinguish speech and a feeling of pressure in the ear. 

Causes can stem from minor obstructions or fluid trapped in the ear canal, such as when ear wax builds up and traps fluid, to more severe causes and damage, such as exposure to loud music over a long time. Aging, congenital disabilities, genetic elements, and trauma are all other common causes of hearing loss.

The Main Types Of Hearing Loss

Hearing loss is identified into three categories which are: 

  • Conductive Hearing Loss: Conductive hearing loss is defined as hearing loss caused by a blockage in the outer or middle ear, preventing sound from reaching the inner ear and brain, and may only be temporary. 
  • Sensorineural Hearing Loss: Sensorineural hearing loss is when there is an issue within the inner ear or auditory nerve that prevents sound from reaching the brain. Typically this type of damage is permanent, though with hearing aids and other amplification, total hearing loss may be remedied to some degree.
  • Mixed Hearing Loss: Mixed hearing loss occurs when a blockage occurs in the outer or middle ear, and there is permanent damage to the inner ear or auditory nerve.

There may be non-surgical remedies available with Conductive hearing loss, though more severe levels of Conductive hearing loss surgery or hearing aids may be needed. 

In Sensorineural hearing loss cases, there are no surgical options available to repair the tiny hairs that make up the inner ear. Still, implanted cochlear hearing aids may assist with limiting less severe sensorineural hearing loss

In Mixed hearing loss, the remedies are dependent on whether the damage is conductive or sensorineural hearing loss. Once the determination is made, your doctor or audiologist will explain the corrective procedures and options available.

The 4 Levels Of Hearing Loss

There are four levels of hearing loss ranging from mild, moderate, severe, to profound. The damage of hearing loss in each stage increases in intensity, moving from mild impairment to almost complete hearing loss at the profound level.

Mild Hearing Loss

Mild hearing loss can be temporary, such as when you get a head-cold or get some fluid trapped in the ear. With so many people wearing earbuds, this is the most prevalent of hearing loss levels. 

With mild hearing loss, sounds are slightly muffled, and certain sounds may be somewhat more challenging to hear than with undamaged hearing. For sufferers at this level, soft-spoken people and young children are in the hearing range that is more difficult to hear than with average hearing ability. 

Another issue sufferers have at hearing speech at an average volume in a noisy environment such as a busy restaurant is a little more challenging to hear. At the higher level of mild hearing loss, consonants may seem complicated, especially softer ones such as the letter “s. This hearing loss level is similar to putting fingers into your ear or wearing earplugs, you can still hear, but it may be a little softer and slightly tricky.

Moderate Hearing Loss

Moderate hearing loss is the stage just beyond the mild stage. With average hearing loss, sufferers may have difficulty casual speech volume with television and radio volume at an average level is challenging to hear. Often sufferers will ask for speakers to repeat themselves, and sufferers may unknowingly begin to lip-read to sound out garbled words.

In addition to certain consonants being challenging to hear, vowels become indecipherable at the higher end of moderate hearing loss. For sufferers at this level of hearing damage, sounds can be heard but making out words in conversation may be very difficult.

Severe Hearing Loss

At this hearing loss stage, hearing everyday speech and sounds cannot be deciphered without some hearing assistance like with a hearing aid. In other words, speech comprehension is challenging without amplification, and sounds in a loud environment will be heard as just a wall of noise.

At this level of hearing loss, even regular speech can’t be heard without amplification. Even with hearing aids, there may be difficulty understanding words as the process of amplification, especially with analog hearing aids, may increase the volume of sound but not improve the clarity of sound.

Profound Hearing Loss

Profound hearing loss can vary from near deafness to absolute deaf. Loud noises and explosions are almost unheard and typical everyday speech, and sound cannot be heard, even with sound amplification.

At this level of hearing loss, even with hearing aids, everyday speech is unclear, and the sufferer may not have the ability to hear the speech at all. At this stage of hearing loss, sufferers should transition to other communication methods, such as with sign-language and writing words, as the best option to communicate.

How We Hear

As discussed earlier, hearing is the energy traveling process through the outer, middle, and inner ear, which is translated to the brain and hear a sound. 

When the hearing is normal, we can listen to higher pitches and softer sounds than if there is some type of blockage or other types of damage in the hearing process.

Image of anatomical model of the ear

 

The outer ear is the part of the ear that we can see, such as the ear lobe and the ear structure, known as the pinna and ear canal. The eardrum is also known as the tympanic membrane, separates the outer and middle ear.

The middle ear consists of three little bones, the ossicles, or better known as the hammer, anvil, and stirrup, as well as the eardrum. 

The inner ear has the snail-shaped cochlea, the hearing nerve, and spiral-shaped bones that aid balance. 

As sound moves through the three stages of the auditory canal, any damage or blockage inhibits transmitting sound through the canal, then hearing loss results.

Additionally, the hearing nerve runs from the inner ear to the brain, transmitting energy converted to sound.

How Sound is Measured

Sound is measured in two ways, volume and frequency. To know your hearing levels, you need to get an audiogram that will measure the volume at which you can hear a sound,  the frequency range you can listen to, and a test for any causes of hearing loss. 

It is measured in units known as decibels or dB for short to measure the volume of sound. The higher the number of dB, the louder the sound, and in some forms of hearing loss (profound), even the most audible sounds may be unheard. 

Certain sounds operate on the lower end, such as breathing at 10 dB, while louder sounds such as a gunshot operate at 140 dB. Any sound over 140 dB begins to be at the threshold to cause pain in the listener and, without sound muffling, will cause damage to the listener.

 

Chart of the various severities of hearing loss

 

Frequency is measured in units known as Hertz, or Hz. Frequency, also known as pitch, ranges from 250 Hz to 8000 Hz, within the normal range of human speech.

How Hearing Loss Is Measured

As discussed, hearing loss is measured in what volume level is needed for sounds to be heard and which frequencies are easier or harder to hear.

How A Hearing Test Works

A hearing test is performed by an audiologist who is a hearing specialist. Typically there are three main types of hearing tests to determine the severity and type of hearing damage.

 

Diagnostic charts of different levels of hearing loss

 

In the first test, the patient will sit in a soundproof room with headphones while the audiologist sends different sounds and pitches and asks for a specific response when the sound is heard. 

For example, if testing the left ear, the patient is directed to raise their left hand once a sound is heard in the left ear. Sounds of various levels and frequencies will be increased until there the patient responds. 

The next test consists of two parts and will use a tuning fork placed alongside the head either behind the ear, known as the Rinne Hearing Test, or along the forehead, known as the Weber Hearing Test.

The Rinne Test And The Weber Test

The Rinne test will check the patient to see if the hearing issue is conductive hearing loss or air conductive loss. 

When the hearing is impaired because of blockages in the outer or middle ear, it is reflected in air conductivity. When the patient can hear the tuning fork against the mastoid bone (behind the ear), the damage is to the inner ear. 

For the Weber test, the tuning fork is placed on the center of the forehead. The sound will be heard stereophonically in normal hearing, which just means heard by both ears simultaneously. 

The tuning fork will be moved laterally or side-to-side to determine the type of hearing damage. When hearing loss is conductive, it will be heard in the same ear from where the tuning fork is placed, and when it’s sensorineural hearing loss, the sound will be heard in the opposite ear.

Understanding Hearing Loss For You And Your Loved One

Whether you or a loved one is experiencing hearing issues, you should consult your doctor and ask to receive a hearing test. Many forms of hearing loss are correctable with hearing aids or cochlear implants. 

Many preventable hearing damages include wearing proper ear protection when planning on being exposed to sudden and prolonged loud noise. 

Understanding the four levels of hearing loss, the types of hearing damage, and the remedies available to you is essential. But getting a professional diagnosis and hearing test to determine the type and extent of damage to your hearing is crucial.

 

Profile photo for Drew Sutton

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.

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