Many people view hearing loss as an all-or-nothing proposition, when in reality it exists on a continuum. It can be as subtle as difficulty perceiving a certain frequency, or as severe as near-deafness.
With such a level of variation, each case of hearing loss is unique. Understanding everything that characterizes your degree of hearing loss allows you to get the help adapted to your situation.
Here is a detailed examination of each category of hearing loss, the mechanisms that cause it, as well as everything you need to know about it.
How does hearing loss occur?
Hearing loss can be a difficult diagnosis to accept. Just a few years ago, your hearing was most likely intact. Today, you are told that you have lost some of your ability to hear. Presbycusis is a common problem affecting a large part of the population, but few truly understand why their hearing has declined.
Here's some insight into the underlying reasons for this diminished perception of sounds. Understanding the science and physiology behind hearing loss helps to demystify it. It also allows you to take action to protect and preserve the hearing you have left.
How does hearing work?
Humans have a wide range of senses that allow them to gather information about their environment. Sight, taste, touch, smell, and hearing allow you to live your daily life. Most people never wonder how these senses work, yet it is valuable knowledge to have in your toolbox.
Hearing is the sense that allows us to detect differences in ambient air pressure, caused by vibrations. When an object vibrates, it emits sound waves that disturb the air.
These travel from the sound source to your ear, where the outer ear funnels the sound into the ear canal. At the end of the ear canal is a thin membrane called the eardrum. It oscillates back and forth under the effect of air pressure variations. Behind the eardrum, a series of small interconnected bones transmit this movement to the inner ear.
The inner ear is the part of the ear that transforms this movement into a nerve signal, then relayed to the brain and perceived as sound. The inner ear functions thanks to an organ called the cochlea. The cochlea is a hollow, snail-shaped structure that houses hundreds of sensory hair cells.
The ossicles of the middle ear strike the inner ear and propagate vibrations throughout the cochlea. Each hair cell in the cochlea is tuned to a precise sound frequency. When this frequency is detected, the cell bends, triggering a nerve impulse.
What is conductive hearing loss?
Conductive hearing loss is a form of hearing loss that occurs upstream of the inner ear. A blockage in the ear canal, a perforated eardrum, or middle ear problems can all contribute to it.
Many cases of conductive hearing loss improve over time, and hearing is usually recovered. This type of hearing loss can affect both ears or just one: this is called bilateral or unilateral hearing loss.
What is sensorineural hearing loss?
Sensorineural hearing loss is hearing loss that occurs in the inner ear or at the auditory nerve itself. Unlike conductive hearing loss, there are few solutions to recover lost hearing.
The most common cause of sensorineural hearing loss is a decrease in the sensitivity of the hair cells in the cochlea. A lifetime of sounds, or a single exposure to loud noises, can eventually damage these cells and reduce their ability to detect their specific frequency.
A higher sound intensity is then required for the sound to be perceived. This is why many people with hearing loss need their interlocutors to speak louder.
Degrees of hearing loss
While hearing loss is divided into two main types, there is a universally used scale to determine its severity: the hearing loss scale.
This scale is based on decibels of hearing loss (dB HL) and assigns a numerical value to the sound volume you are able to perceive. The higher the hearing loss range, the more severe the hearing loss.
The hearing loss scale is valuable because it helps everyone understand the severity of their hearing loss. It also informs about the best support solutions. Here is a detailed examination of the degrees of hearing loss, their decibel ranges, and the sounds you might have trouble hearing.
Slight hearing loss
Slight hearing loss corresponds to a range of 16 to 25 dB HL. Concretely, this means that if the faintest sound you perceive is within this range, you have slight hearing loss. Unlike other forms, it generally has little impact on your ability to communicate effectively with others.
Sounds that are difficult to perceive in this case are whispers, birdsong in the distance, and possibly some speech sounds when speaking softly. Slight hearing loss often goes unnoticed or is simply accepted, as it is quite easy to live with.
Mild hearing loss
Mild hearing loss corresponds to a range of 26 to 40 dB HL. 40 dB is roughly the sound level of a quiet library. Mild hearing loss should not bother you in daily life. However, it can make it harder to perceive softly spoken words. It also becomes more difficult to understand people in an environment with significant background noise.
Mild hearing loss can nevertheless eventually affect your daily life: you may consider hearing aids to remain fully present in your conversations.
Moderate hearing loss
Moderate hearing loss corresponds to a range of 41 to 55 dB HL. A normal conversation is around 60 dB, which means that affected individuals probably have difficulty hearing what others are saying. Add a noisy background, and they are very likely to lose the thread of the discussion.
In cases of moderate hearing loss, it is generally recommended to equip yourself with hearing aids to bring these sound levels above your hearing threshold and preserve your ability to communicate orally.
Severe hearing loss
Severe hearing loss corresponds to a range of 71 to 90 dB HL. Affected individuals generally cannot hear a normal conversation. They usually only perceive loud sounds, such as a motorcycle, a lawnmower, or power tools. Hearing aids are extremely useful to them and allow them to participate in conversations.
Profound hearing loss
Profound hearing loss is the highest degree of hearing loss: it is essentially considered near-deafness. Most sounds are not perceived by affected individuals. Only very loud sounds are perceptible, and even then, not always distinctly.
Hearing aids can help people with profound hearing loss, but they often require specific devices powerful enough to amplify sounds beyond their high hearing threshold.
What else you should know
The degree of hearing loss is an excellent way to quickly communicate the extent of hearing loss, but there's a lot more to know.
Here's everything else you need to remember about hearing loss:
How is the degree of hearing loss determined?
Hearing loss is assessed by a hearing test called an audiometry. Audiometry is performed by an audiologist. During this test, headphones and a series of pure tones are used to assess hearing acuity.
Sounds are broadcast at different volumes and the lowest perceived intensity is noted. At the end of the test, you will know exactly which sounds you hear and which you do not. The degree of hearing loss can then be determined.
What can help with hearing loss?
One of the best things to do for hearing loss is to get hearing aids. These are small devices that pick up sound and amplify it to a higher volume. Most have a volume setting that allows them to be adapted to your degree of hearing loss. The CLARIA EV1 is an excellent option for starting with affordable hearing aids.
Knowledge is power
The degree of hearing loss measures the severity of hearing loss. This can be caused by a malfunction of any part of the ear, but all these impairments result in a reduced ability to perceive sounds. Understanding the different degrees of hearing loss gives you a more complete picture of the subject and allows you to place your own case on this continuum.
Sources
Types of Hearing Loss | CDC
Degree of Hearing Loss | ASHA
The Hidden Risks of Hearing Loss | Johns Hopkins Medicine
