Hearing loss explained: symptoms, causes and treatment options

If you’re experiencing difficulty hearing or you’re concerned about a loved one who’s struggling to keep up with conversations, you might have lots of questions.

Hearing loss can happen for a variety of reasons. Some types of hearing loss are temporary and can be treated, while others are permanent and may gradually worsen over time.

Sudden hearing loss in one ear or both ears is a medical emergency, and if you experience it you should seek medical advice straight away.

Around 37.5 million adults in the US report they have hearing problems – that’s around 15% of the population. Half of people aged 75 and older have disabling or severe hearing loss.

There are three main types of hearing loss:

• Sensorineural hearing loss
• Conductive hearing loss
• Mixed hearing loss

Each type affects a different part of the auditory system – the body’s system that’s responsible for our sense of hearing and how we understand sounds.

Hearing loss can be caused by advancing age, exposure to loud noise, genetics, a blockage in the ear, and infections, among other things.

Depending on the type and cause of hearing loss, treatments may be available, the most common being hearing aids.

What is hearing loss?

Hearing loss is when you can’t hear as well as someone with ‘normal’ hearing. Sound is measured in decibels (dB) and you are said to have very slight or mild hearing loss if you cannot hear sound below 15-20 dB.

Hearing loss happens when sound signals don’t reach the brain. To understand how and why, it helps to know a little about the auditory system and how hearing works.

The auditory system is responsible for our sense of hearing and how we understand sounds. It includes the ears, the nerve connecting the inner ear to the brain, and parts of the brain that process sound.

The ear is made up of three sections:

• The outer ear
• Middle ear
• Inner ear

Sound is made when something vibrates and causes the air around it to vibrate. These vibrations cause the energy in the air to move in a pattern, creating a sound wave.

Sound waves enter the ear canal and travel to the eardrum, causing the eardrum and the tiny bones in the middle ear – called the ossicles – to vibrate.

The vibrations in turn pass to the inner ear and the cochlea, a hollow, snail-shaped structure that’s filled with fluid and lined with thousands of tiny hair cells.

The hair cells convert the vibrations into electrical impulses, which travel through the auditory nerve to the brain. The brain then interprets these electrical impulses as sounds.

When we experience any degree of hearing loss, it’s because something has gone wrong somewhere in the auditory system.

Types of hearing loss

The three main types of hearing loss are sensorineural hearing loss, conductive hearing loss, and mixed hearing loss.

Sensorineural hearing loss

This occurs as a result of damage to a part of the inner ear or the auditory nerve. Often, sensorineural hearing loss is caused by damage to the tiny hair cells in the cochlea, which means they are unable to convert sound waves into electrical impulses.

There is usually no treatment or cure for sensorineural hearing loss. In fact, it’s the most common type of permanent hearing loss. But if you have sensorineural hearing loss, wearing a hearing aid will usually help you to hear better.

Sudden hearing loss is sensorineural, and usually occurs very quickly – immediately or over a few days – for no obvious reason.

You might notice it when you wake in the morning or when you put a phone to the affected ear. Or you might experience a ‘pop’ sound or sensation immediately before the sound goes.

In around 85-90% of cases, the cause of sudden hearing loss can’t be found. Where identified, causes include head trauma, autoimmune or neurological disease, ototoxic medication, tumor, circulatory problems, or inner ear disorders like Meniere’s disease.

If you experience sudden hearing loss, you should seek medical advice straight away. Getting diagnosed and treated quickly will improve your chances of recovering at least some of your hearing.

Conductive hearing loss

This occurs when soundwaves are blocked from moving through the outer or middle ear, stopping sound from reaching the inner ear.

It occurs as a result of a problem with or damage to part of the outer or middle ear, which includes the ear canal, eardrum, and the ossicles – the three tiny bones in the middle ear that pass soundwave vibrations to the cochlea in the inner ear.

Most cases of conductive hearing loss are treatable, either with medication or surgery, and depending on the exact cause, some types of hearing aids.

Mixed hearing loss

As the name suggests, mixed hearing loss occurs when you have a combination of conductive hearing loss and sensorineural hearing loss. This can happen if you have sensorineural hearing loss and develop a problem with your conductive hearing on top.

For example, you might have a degree of noise-induced hearing loss and develop an infection that causes a build-up of fluid in your middle ear.

Again, hearing aids can help to improve mixed hearing loss, although it’s important that any treatable factors are managed, too. In the above example, you might be prescribed antibiotics or other medication to treat the infection.

Auditory neuropathy

This is a lesser-understood type of hearing loss, and it’s not known how many people it affects.

In this type of hearing loss, the inner ear detects and processes soundwaves but there is some problem transmitting them from the inner ear to the brain.

If you have auditory neuropathy, you might appear to have normal hearing or very mild hearing loss when it’s assessed during a hearing test. On the other hand, you could have quite severe hearing loss.

Either way, you’re likely to have difficulty with speech perception and understanding.

Researchers are continually investigating auditory neuropathy to improve understanding and diagnosis.

Hearing loss symptoms

Many people don’t realize they have hearing loss because it happens gradually over a long period of time. Often, loved-ones notice the signs of hearing loss before you recognize anything is different.

Hearing loss in children and babies will manifest differently and have different signs. But in teens and adults, hearing loss signs include:

• Trouble hearing people speaking, especially in crowded, noisy places
• Having to ask people to repeat themselves or talk more slowly
• People’s voices sounding muffled
• Having to turn the volume up on the TV or radio more and more
• Struggling to distinguish consonant sounds
• Finding it hard using the phone
• Avoiding social situations or becoming increasingly isolated because you find it hard to keep up with conversations
• Getting tired or stressed, having to focus more while listening

You might feel embarrassed or uncomfortable at the prospect of losing your hearing. But it’s important to remember that the sooner you have your hearing tested and the cause of your hearing loss diagnosed, the more likely it is to be successfully treated and better managed.

Degrees of hearing loss

Hearing loss is often categorized as mild, moderate, severe, or profound. It can be measured according to how loud sound needs to be for you to hear it, known as hearing loss range (decibel hearing loss, or dBHL).

Mild hearing loss

Hearing loss range is 20-40 dBHL. You have difficulty hearing soft or high-pitched speech and distinguishing some consonant sounds. You might not be able to hear the noise of a refrigerator or water in a stream.

Moderate hearing loss

Hearing loss range is 41-70 dBHL. As well as the above, you find it harder to hear vowel sounds and might struggle to understand speech without a hearing aid. You might not hear if it’s raining, or people working in an office, for example.

Severe hearing loss

Hearing loss range is 71-95 dBHL. You can’t hear speech without hearing aids or a cochlear implant. You probably won’t hear the phone or doorbell ringing, the sound of traffic, or a vacuum cleaner is used.

Profound hearing loss

Hearing loss range is 95 dBHL or higher. Without hearing aids, you might be unable to hear very much at all. It’s likely you won’t be able to hear if someone shouts at you, or the noise of aeroplanes above and fire alarms.

Diagnosing hearing loss

If you think you have hearing loss, the first step is to visit an audiologist who will perform some hearing tests to assess the degree of hearing loss and identify any potential causes.

The outcomes of these tests will help determine the best treatment.

Hearing loss treatment

Depending on the type and cause of hearing loss and its severity, it can be treated in different ways.

If you have conductive hearing loss caused by a build-up of wax, for example, you can have treatment (microsuction or water irrigation) to remove the wax. If you have an infection that’s causing your hearing loss, your doctor might prescribe antibiotics.

In some cases, more invasive treatment is needed for conductive hearing loss. Surgery can often correct congenital malformations of parts of the ear or damage to structures in the middle ear resulting from head trauma.

Some cases of sensorineural hearing loss can be managed with medication. For example, if an underlying health condition is a cause – an autoimmune disease, Meniere’s disease, or a viral infection, for example – treatment of the condition will often remedy or minimize the impact of your hearing loss.

However, most cases of sensorineural hearing loss cannot be treated medically and you will need to wear a hearing aid to get any improvement in your hearing. Hearing aids are also recommended for some people with conductive hearing loss.

If hearing aids don’t work or you don’t get any significant improvement, then depending on the cause of your hearing loss you might be a candidate for a cochlear implant.