Types and Causes of Hearing Loss: Why it Doesn’t Just Affect Old People
Age-related hearing loss may be one of the main causes of hearing impairments, but age is not the only factor to blame. One in six Australians currently suffers from hearing loss and about a third of those people lose their hearing through preventable means. We’re taking a look at the types and causes of hearing loss, to support you on your way to better hearing health!
How Does Your Hearing Work?
In order for you to perceive sound, the following occurs in a healthy hearing:
- When sound waves enter your ear, they cause a change in air pressure. This makes your eardrum vibrate.
- This vibration is then passed on through three tiny bones (the ‘ossicles’) in the middle ear, namely the malleus, incus, and stapes. Here, sound vibrations are translated into a fluid.
- The vibrations continue their journey to the cochlea, a key hearing structure. There, the sound waves move tiny hair cells up and down, which creates an electrical signal.
- Your auditory nerve carries this signal to the brain, where the sound is processed.
What is Hearing Loss?
Hearing loss is defined as the partial or total inability to hear and can affect people of all ages and walks of life. Some people can experience hearing loss in only one ear, others may have hearing loss in both ears. The extent of the hearing loss typically depends on the underlying cause.
Typically, hearing loss is divided into three categories:
- Conductive hearing loss,
- Sensorineural hearing loss,
- And mixed hearing loss.
1. Conductive Hearing Loss
A conductive hearing loss occurs when anything that happens prior to sound reaching the cochlear is not working properly. Depending on the underlying cause, a conductive loss can affect one ear or both ears. There are many different types of Conductive Hearing Loss, but we will the most common ones, their causes and treatment options below.
Tympanic Membrane Perforation
Hearing loss may occur if the Tympanic Membrane, or eardrum, has a hole. The Tympanic Membrane is a very taut membrane which is why we refer to it as a drum. It vibrates when it picks up sound. If it is punctured or otherwise damaged, due to infection or trauma, the eardrum may not vibrate as intended, and therefore cannot pass on vibrations.
This will cause a hearing loss in the ear with the perforation. Really anyone can have a Tympanic Membrane perforation, no matter their age. It can be treated surgically, but in most cases, ruptured or perforated eardrums heal on their own. If you suspect that your eardrum may be ruptured, do not hesitate to contact your GP. Otherwise, you may risk serious health problems down the line.
Tympanic Membrane Perforation is typically caused by:
- Increased pressure in the ear as a result of infection
- Trauma to the eardrum, e.g. caused by objects being inserted into the ear
Similar to a perforation, Ossicular Disarticulation refers to the disarticulation or separation of the ossicles, the tiny bones that transmit the vibrations captured by your eardrum. As a result, sound can not be transmitted properly, resulting in conductive hearing loss.
In normal hearing, the largest ossicle, the malleus, picks up vibrations at the eardrum and passes these on to the incus. The incus then passes these on to the stapes, the smallest and strongest of these three bones.
Sudden head trauma can cause these bones to separate, which means vibrations cannot be properly transmitted, and a conductive hearing loss is caused in the ear with the affected bones. Anyone who knocks their head hard enough may suffer from a disarticulation.
Damaged ossicles may heal on their own, but can be surgically repaired or replaced with artificial bone.
Causes of Ossicular Disarticulation may include:
- Trauma to the head, including blast injuries and lightning strikes
- Ear infections
- Eustachian tube dysfunction
Otitis Media is more commonly known as a middle ear infection. It can cause hearing loss in one or both ears if the infection has spread. Some people may only experience Otitis Media once or twice in their life, and others can experience it chronically.
Children commonly suffer from Otitis Media because of the shape of their Eustachian Tubes, the tube that connects the nose, mouth and ears. In children, the cartilage of this tube is less stiff than with adults, meaning it is more prone to obstruction. When the tube becomes obstructed, fluid is unable to drain. This fluid then builds up and can lead to problems hearing, another type of conductive loss.
Possible causes of Otitis Media or middle ear infections:
- Common cold or flu
- Bacterial infections
- Sinus infections
Wax is a protective substance that is created by the outer ear and gradually moves from near the Tympanic Membrane to the outside of the ear. Wax is important as it protects the ear due to its antibacterial properties. However, sometimes too much wax can build up and cause a conductive hearing loss in one ear, or in both ears.
When you’re cleaning your ears, wax sometimes ends up being pushed back down into the ear canal, where it builds up over time. This will cause a hearing loss in that ear, as the sound can’t reach the tympanic membrane.
2. Sensorineural Hearing Loss
Sensorineural hearing loss is normally divided into two main types: Sensory and neural hearing loss.
Sensory hearing loss refers to the inability of the cochlea to detect sound, often because the tiny hair cells may be affected by natural factors such as age, genetics or external factors like excessive sound. These hair cells are finite and have no way to regenerate. When they are damaged, your hearing will gradually decline. This type of sensorineural hearing loss is also known as a ‘cochlear’ loss because it occurs in the cochlea.
Neural hearing loss occurs when the hair cells are picking up sound vibrations, but the signal can’t travel to the brain. This is often caused by problems with the central nervous system, or problems with the nerve that is responsible for sending the auditory signals from the cochlea to the brain. Because the cause of a neural hearing loss lies behind the cochlea, we often refer to it as ‘retrocochlear’ hearing loss.
Age-related hearing loss
Hearing loss related to age is very common and typically affects both ears, although at different rates. Some people will find that their hearing loss in one ear is worse or feels worse than the hearing loss in their other ear. Age-related hearing loss is a natural occurrence and may occur in the absence of external factors, due to the natural degradation of hair cells in the cochlear.
It is important to remember that while this type of hearing loss is not reversible, it can be treated and should therefore be detected as early as possible. Hearing loss is linked to dementia and other conditions related to cognitive health. We, therefore, urge you to take it seriously and to schedule an appointment with your trusted, local audiologist for a diagnostic hearing test.
Noise-induced hearing loss
Being exposed to significantly loud noises on a regular basis can also cause hearing loss. Consistently loud noise degrades the cochlea over time, effectively speeding up the process of aging. Some people will find that they experience noise-related hearing loss worse in one ear compared to the other.
Those who fire guns regularly, for example, will find that they have a greater hearing loss in the ear that is closer to the muzzle, the source of the sound. Someone who is exposed to power tools or loudspeakers that are consistently on their right-hand side may experience noise-induced hearing loss in both ears, but the hearing loss will be worse in one ear.
Loud noises like gunshots or a plane taking off likely won’t permanently damage your hearing, but will instead cause a Temporary Threshold Shift, or TTS. After a loud concert, for instance, you may feel like you cannot hear out of your ears, which is often accompanied by tinnitus, a ringing in your ears.
Typically, the Tinnitus will fade, and your hearing will after a few hours return to what it was before. Being around loud noises constantly, however, may cause sensorineural hearing loss.
The best way to prevent this sort of hearing loss is by avoiding exposure to loud noise or protecting your ears when using earmuffs or custom made earplugs. This can prevent your ears from being damaged by a loud noise. Most workplaces will have guidelines on the acceptable levels of noise for you to be exposed to on a regular basis.
Auditory Neuropathy, or ‘Auditory Neuropathy Spectrum Disorder’ refers to problems with the auditory nerve. Here, the error occurs when the information travels to the brain via the auditory nerve. After the signals are sent from the cochlea along the auditory nerve, these impulses are disrupted.
For this reason, people with Auditory Neuropathy who take a hearing test may see that they have a hearing loss, due to the problems with the cochlea, but their ability to understand spoken words is poorer than expected. Sometimes, the affected person is able to hear, and scores very well on a hearing test, but is completely unable to understand spoken words.
Auditory Neuropathy is classified as a sensorineural hearing loss because it affects the auditory nerve and brain but may also affect the cochlea as well.
An acoustic neuroma, or vestibular schwannoma, is a benign tumour that develops on one of the nerves leading to the brain. Think of nerves as electrodes, where a nerve impulse (i.e. a piece of information about what you hear) is sent along the nerve like a bolt of electricity. Nerves can be either sensory (used for the brain receiving information) or motor (used for the brain sending information).
The Vestibulocochlear (or Auditory) Nerve is a cranial nerve and splits into two different branches. The cochlear nerve branch is a sensory nerve that takes the sound we hear to the brain. The vestibular nerve branch carries information about our balance to the brain. If a tumour grows on the cochlear nerve, this can squash the nerve and slow down the speed of the nerve impulses travelling along the nerve.
What Should You Do if You Have Trouble Hearing?
Hearing loss can affect people of different ages, both young and old. In general, people are more susceptible to hearing loss as they age due to a natural decline in their hearing or due to life events such as extended noise exposure or traumatic injury to the head or ears. Hearing loss can occur in one ear as well as in both ears, depending on the cause of the hearing loss.
If you are worried about your hearing health, don’t hesitate to contact the friendly team at Attune Hearing. With over 50 accredited clinics Australia-wide, we are passionate about helping you find the best possible solution catered to your needs and preferences. Built on a medical foundation and independent from hearing aid manufacturers, the health and well-being of our patients will always come first.