How Do We Hear?
The Hearing
Process
Sound waves enter the outer ear and channel along the ear canal to the eardrum. The impact of the waves on the eardrum creates vibrations, which are transferred through a series of three tiny bones. The third of these bones is connected to a delicate, snail shaped structure called the cochlea. The cochlea is filled with fluid and lined with thousands of microscopic hairs. The vibrations are transmitted to the fluid inside the cochlea, where the hairs are bent by the wave like action of this fluid.
The bending of these hairs sets off nerve impulses, which are then passed through to the central auditory nerves. The auditory nerves carry the signal to the primary auditory cortex, or hearing centre of the brain, which translates the impulses into what we perceive as sound.Any breakdown in this complex system, at any point along the pathway from the outer ear to the brain, can result in a degree of hearing loss. Understanding where that breakdown occurs is the foundation of accurate diagnosis and effective treatment.
The Three Parts of the Ear
The human ear is divided into three main sections, each playing a distinct and essential role in the hearing process.
The Outer Ear
The outer ear consists of the pinna, which is the visible part of the ear on the outside of the head, and the ear canal. The pinna acts like a funnel, collecting sound waves from the environment and directing them inward through the ear canal toward the eardrum. The ear canal also produces ear wax, which serves as a natural protective barrier against dust, debris and infection.
The Middle Ear
The middle ear begins at the eardrum, also known as the tympanic membrane. When sound waves reach the eardrum, it vibrates and sets three tiny bones into motion. These bones, known as the malleus, incus and stapes, form a connected chain that amplifies and transmits the vibrations toward the inner ear. The middle ear is also connected to the back of the nose and throat via the Eustachian tube, which helps equalise air pressure on both sides of the eardrum.
The Inner Ear
The inner ear contains the cochlea, a fluid filled, spiral shaped structure lined with thousands of microscopic hair cells. When vibrations from the middle ear reach the cochlea, the fluid inside moves and causes the hair cells to bend, generating electrical nerve impulses. These impulses travel along the auditory nerve to the brain, where they are interpreted as recognisable sound. The inner ear also houses the vestibular system, which plays a vital role in balance.
Signs of hearing loss
When Does Hearing Go Wrong?
Any disruption to the hearing pathway can lead to hearing loss. The location and nature of that disruption will determine the type and severity of the loss experienced. Common signs that the hearing system may not be functioning as it should include:
Difficulty following conversations in noisy environments
Frequently asking others to repeat themselves
Turning up the volume on the television or radio
Struggling to hear on the phone
Mishearing words or misunderstanding speech
A feeling of fullness or blockage in one or both ears
Ringing or buzzing sounds in the ears with no external source
Difficulty hearing people speaking from another room
If you are experiencing any of these signs, a comprehensive hearing assessment with one of our audiologists at Acute Hearing Solutions can determine the cause and identify the most appropriate course of action.
Types of Hearing Loss
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Conductive
Hearing Loss
Conductive hearing loss occurs when sound cannot efficiently pass through the outer or middle ear. Sounds may seem quieter or slightly muffled, though clarity can often be restored by increasing volume. Essentially, a mechanical barrier is preventing sound vibrations from reaching the inner ear
Common Causes
Earwax blockage (cerumen impaction)
Middle ear infections (otitis media)
Fluid behind the eardrum
Earwax blockage (cerumen impaction)
Eardrum perforation
Problems with the ossicles, such as otosclerosis
Narrowing or malformation of the ear canal
Sensorineural
Hearing Loss
Sensorineural hearing loss results from damage to the inner ear (cochlea) or the auditory nerve. This type of hearing loss reduces both volume and clarity and commonly affects the ability to hear speech in noisy environments.
Common Causes
Age-related hearing loss (presbycusis)
Noise exposure (workplace, concerts, machinery)
Genetic factors
Ototoxic medications
Viral or bacterial infections affecting the inner ear
Head trauma or neurological conditions
Mixed
Hearing Loss
Mixed hearing loss is a combination of conductive and sensorineural loss. For example, a person may have age-related inner ear changes alongside a middle ear infection.
Common Risk Factors for Hearing Loss
Long-term noise exposure
Family history of hearing loss
Increasing age
Chronic health conditions (e.g., diabetes)
Frequent ear infections in childhood or adulthood
Use of ototoxic medications
— hearing protection
Protecting Your Hearing Before
Hearing loss
The best time to protect your hearing is before any damage takes place. Once the delicate hair cells inside the cochlea are damaged, they do not regenerate. Noise induced hearing loss is one of the most common and entirely preventable forms of hearing loss in Australia, accounting for an estimated 37% of all hearing loss cases. Prolonged or repeated exposure to sounds above 85 decibels can cause permanent and irreversible damage to the inner ear structures, impacting not only your ability to hear but also your quality of life and your relationships with family, friends, and colleagues.
At Acute Hearing Solutions, we offer a range of hearing protection solutions to suit different environments, lifestyles, and levels of noise exposure. Our audiologists can assess your situation and recommend the most appropriate option for your needs.
Custom-made noise attenuating earplugs: Also known as musician's earplugs, these are custom moulded to fit your individual ear canal and contain a precision filter that reduces noise to a safe level while keeping sound quality as natural as possible. The filter level can be customised based on your preferences and the environment you plan to use them in.
Passive custom-made earplugs: These are custom moulded in the same way as noise attenuating plugs but do not contain a filter. They are designed to reduce as much noise as possible and are well suited to very high noise environments where sound quality is less of a priority.
Non-custom earplugs: A practical and cost effective option available in a range of sizes, non-custom earplugs are designed for specific noise environments such as industrial workplaces and offer a good level of protection without the need for custom fitting.
Ear muffs: An excellent choice for use in any loud environment, ear muffs generally provide higher levels of noise reduction than disposable plugs and are ideal for situations where verbal communication is not required. They are easy to put on and take off and are widely used in construction, manufacturing, and other industrial settings.
Disposable earplugs: Made from soft foam that moulds to the shape of the ear canal, disposable plugs are a convenient and affordable option designed for single or short term use. They may not be suitable for all users, particularly those with narrow or unusually shaped ear canals.
Custom-made sleep plugs: Crafted from a soft silicone material and custom fitted for overnight wear, sleep plugs are designed to reduce ambient noise comfortably throughout the night. Sleep disturbance can have a significant impact on your physical and mental wellbeing, and sleep plugs can play an important role in ensuring a consistently restful night's sleep.
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