Sensorineural Hearing Loss

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Now, if you’re wondering, “What on earth is sensorineural hearing loss?” don’t fret! It’s simply a fancy term for a type of hearing loss that occurs when there’s damage to the inner ear or the nerve pathways from the ear to the brain.

Your inner ear (pictured below) is like the grand conductor of your hearing system. It contains the cochlea that houses the tiny hair cells that convert sound waves into electrical signals and then send them to the brain. When these hair cells or the nerve pathways between your ear and brain are damaged, it causes sensorineural hearing loss.

And guess what? Sensorineural hearing loss (SNHL) is more common than you might think.

Globally, sensorineural hearing loss (SNHL) is the most common type of hearing loss. SNHL accounts for 9 out of 10 reported cases of hearing loss. And with more than 880,350 Kiwis having some form of hearing loss, most of those 1 in 5 people have the SNHL type. 

In most cases, SNHL sneaks up on us gradually over the course of many years. But here’s the twist: it doesn’t just impact our ability to hear certain sounds. It can also affect the frequency range we can pick up on. That means it may be harder to distinguish between high-pitched sounds (like birds chirping or kids talking) versus low tones like adult male conversational speech.

And that’s not all – some lucky folks might experience a lovely symphony of ringing in their ears (aka tinnitus) or even a bout of dizziness or lightheadedness (vertigo). So what are the culprits behind this mischief? The most common is good ol’ age-related hearing loss (presbycusis), followed closely by noise-induced hearing loss (NIHL).

Illustrated anatomy diagram of the human ear
Human ear diagram showing the outer, middle and inner ear sections.

What is Sensorineural Hearing Loss?

SNHL, otherwise known as nerve-related hearing loss, occurs when your inner ear structures take a hit. We’re talking about those tiny hair cells inside your cochlear and nerve pathways connecting your inner ear to your brain. 

Let’s break it down even further. Inside your ears, you’ve got some vital parts at play. There’s the sensory organ called the cochlear, the superstar of your hearing system. Then there’s the dynamic duo of the vestibular and cochlear nerves. The vestibular nerve keeps you balanced and in control of those mesmerising eye movements, while the cochlear nerve delivers crucial signals from the cochlear to your brain.

Here’s the kicker – SNHL messes with these inner ear powerhouses, interrupting the flow of neural impulses to your brain. That’s why it’s often referred to as “nerve-related” hearing loss. It’s like a glitch in the system, preventing you from hearing things as clearly as possible.

This interference of neural signals can greatly impact your daily life, resulting in difficulty understanding speech, missing out on general conversations, and even feelings of isolation.

To understand the severity of SNHL, we use a hearing loss scale measured in decibels. Think of it like a measuring stick for how well you can hear. Depending on the intensity, it can be classified as mild, moderate, moderately severe, severe, or even profound.

So, when it comes to SNHL, it’s all about the inner ear drama and the nerve pathways that lead to your brain.

What About "Sudden" Sensorineural Hearing Loss?

Sudden sensorineural hearing loss (SSNHL) is a medical emergency that occurs suddenly and rapidly, with symptoms appearing over three days or less, distinguishing it from the much more gradual onset of SNHL.

The exact cause of SSNHL remains unclear, but viral infections, circulatory issues and head trauma are all believed to be potential culprits. Symptoms may include sudden deafness and tinnitus with or without vertigo. If left untreated, SSNHL can lead to permanent hearing loss.

Fortunately, treatment for SSNHL is available and includes intravenous steroid injections alongside other medications that reduce inflammation in the inner ear structures. With prompt treatment, many patients with SSNHL have regained their hearing – a sign of hope for those affected by this condition.

A human anatomy diagram showing damaged hair cells inside the cochlea which can be caused by sensorineural hearing loss.
Damaged hair cells inside the cochlea can cause sensorineural hearing loss.

5 Possible Causes of SNHL

1. Normal Ageing

As we get older, it’s common for our hearing to decline. This is called presbycusis, which happens when the nerve hair cells in our cochlea degrade over time. This degradation can make it difficult to hear high-frequency sounds, and even lower-frequency sounds may become unclear. Though there is no cure for presbycusis, protecting your hearing from noise exposure is the best defence.

2. Exposure to Loud Noise

Noise-induced hearing loss occurs when excessive noise, usually over a long period, damages the fine hairs in your inner ears that send messages to your brain.

People who love listening to loud music may also be damaging their hearing.

Noise-induced hearing loss can also happen after a one-off exposure to an intensely loud sound, such as an explosion.

WorkSafe NZ recommends keeping noise levels below 85dB on average and 140dB at peak.

If workers are exposed to noise levels above 85dB for eight hours or 140dB at any time, the employer must implement a noise management plan.

Ways to manage noise include eliminating the noise source, substituting quieter machinery, engineering controls such as sound dampeners or silencers, and introducing measures such as job rotation.

3. Drugs That Are Toxic to Your Hearing

Ototoxic medications are those that are known to have the potential to cause hearing loss or other damage to the ear.

While there are many different types of ototoxic medications, some of the most common include certain antibiotics, chemotherapy drugs, and non-steroidal anti-inflammatory drugs (NSAIDs).

In most cases, ototoxicity is temporary and will resolve once the medication is stopped. However, in some instances, ototoxicity can lead to permanent hearing loss. As a result, it is important for patients taking ototoxic medications to be monitored closely by a healthcare provider.

If you suspect you are experiencing ototoxicity, contact your healthcare provider immediately.

4. Diseases and Disorders

Hearing loss may result directly or indirectly from an underlying disease or disorder such as:

  • Meniere’s disease
  • otosclerosis
  • multiple sclerosis
  • chronic ear infections
  • meningitis
  • measles
  • mumps
  • glue ear.

5. Hereditary Causes

Hereditary hearing loss is a form of hearing loss that runs in families. Your genes (not the blue pants kind) might make you more susceptible to hearing loss by contributing to age-related hearing loss, causing some hereditary hearing impairment syndromes, or causing inner-ear mutations that affect your hearing, either at birth or in later life.

For example, otosclerosis is an inherited disorder affecting the middle ear’s bones. In people with this condition, bone growth occurs abnormally around the stapes, a small bone essential for hearing. This can cause the stapes to become fused to the surrounding bone, making it unable to vibrate properly. As a result, sound waves cannot be transmitted efficiently to the inner ear, leading to hearing loss.

What Are the Complications of SNHL?

Sensorineural hearing loss can cause various physical and mental health complications, including difficulty understanding speech, missing out on general conversations, and feeling isolated. It also brings along a range of physical and mental health complications, such as:

  • Difficulty understanding speech.
  • Missing out on general conversations and feeling isolated.
  • Diminished concentration levels.
  • Elevated stress levels.
  • Cognitive decline and difficulties with memory recall or problem-solving.
  • Depression, anxiety, fatigue, and other mental health issues.

Risk Factors of SNHL

Knowing which activities, habits, illnesses or medications can increase your sensorineural hearing loss risk is crucial.

Our handy list?

Genetics have their say. Not much we can do about that!

Viral infections make their mark. 

Head trauma can have an impact.

Medicine has an array of powerful effects — some we seek out, and some not so much. Ototoxicity, also known as toxic hearing loss, fits into the latter category.

Medicines that may be causing your auditory distress or imbalance: look out for aminoglycosides, macrolide antibiotics for infection, antineoplastic agents, usually also platinum-based, inflammatory medication is involved too, as well as drugs that help with fluid storage and digestion called loop diuretics.

Spending too much time vibing to loud tunes is also an excellent way to persuade some hearing impairment. 

Wintertime loneliness (aka obesity) is also a gamble, and too many cigars or ciggies should (as always) be discouraged. 

Chronic health disorders such as diabetes and hypertension can’t be ignored.

Lastly, disruptive autoimmune disorders were identified as factors to factor in.

Awareness of these risks will help safeguard against many of life’s hardships, including SNHL – so join us in the fight to reduce the risk of hearing loss.

How to Prevent SNHL

As Kiwis, we are used to being surrounded by the beautiful sounds of nature, whether it’s the sweet chirping of birds or the swish of waves crashing onto the shore. Unfortunately, sensorineural hearing loss can distort that auditory experience, leaving us isolated and frustrated.

Let’s start with some good news – you can help prevent SNHL! Avoid loud noises or music for extended periods and any known ototoxic medications to lower your risk. Maintaining a healthy lifestyle is essential, including exercising regularly, quitting smoking if applicable, and managing chronic illnesses such as diabetes and hypertension. Genetics also play a role in hearing health, so be sure to get your hearing tested if it runs in your family.

One of the best ways to avoid loud noises and prevent SNHL is to understand how loud is too loud. Noise duration and intensity are the two main components when judging how dangerous a sound is to your hearing. Check out the safe listening chart below to help protect your hearing.

Possible Therapies and Treatment

Fortunately, various therapies and treatments are available to individuals living with SNHL.

Hearing aids are commonly used for mild to severe cases of hearing loss. They can be custom-fit and come in various styles to suit the user’s lifestyle and hearing needs.

Furthermore, bone conduction hearing aids may be suitable for those unable to wear traditional hearing aids due to ear malformation or other physical limitations.

Cochlear implants are another option for more severe nerve-related or profound hearing loss cases. This device is surgically implanted directly into the inner ear, directly stimulating auditory nerve fibres via an electrode array.

In addition, those living with SNHL should consider pursuing counselling from a qualified audiologist. Counselling can help address any underlying concerns associated with SNHL and provide emotional support, especially during the adjustment phase of wearing hearing aids. Moreover, counselling can assist people with SNHL in discovering different techniques to enhance their communication capabilities.

Ultimately, successful treatment for SNHL relies on timely identification and appropriate management strategies. If you think there is an issue, getting your hearing tested is best, as early detection and intervention are crucial to improving your quality of life. Remember – don’t let sensorineural hearing loss slow you down! You can maintain a healthy auditory lifestyle despite SNHL with the right strategies.

Dr Soren Thompson
Dr Soren Thompson
In 2016 Dr Soren Thompson became the new owner of Ear Health. Soren practised as a General Practitioner in Europe before moving to New Zealand in the early 2000s. Not long after arriving, he completed a Master of Audiology and worked as an Audiologist throughout NZ. Soren then started his own business and established several clinics in the Canterbury region. A few years later, he moved to Auckland to manage his Ear Health clinics and the larger franchise.

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