Noise-Induced Hearing Loss – A Guide
What is Noise-Induced Hearing Loss?
Hearing loss is a relatively common condition in the UK. Around one in six people suffer from some form of impaired hearing, and for most, it’s a condition that is caused by the natural ageing process. However, for others, hearing loss can occur as a result of exposure to high levels of noise over a prolonged period of time.
We call this form of hearing impairment noise-induced hearing loss. It’s commonly caused by working in a noisy environment or listening to music that’s too loud. In this article, you’ll learn more about this form of hearing loss, what causes it, and the treatment that’s available to you.
Understanding Noise-Induced Hearing Loss
In order to understand noise-induced hearing loss, it’s important to first understand the concept of noise – and how it interacts with our ears.
We describe noise in terms of its pitch (frequency) and volume (intensity). When noise enters our ears, it comes into contact with the cochlea – which is the part of the inner ear that deals with audio sound. The cochlea has two forms of hair cells, which work together to help us to hear. One type of hair cell responds better to high frequency noises, the other responds better to low frequencies.
However, when these hair cells become damaged, that’s when we struggle to hear certain sounds.
Understanding the damage:
The human ear can only cope with noises that are within a certain frequency and intensity. If it’s exposed to sounds that are above or below these accepted ‘normal’ sounds, it results in greater impact on the cochlea’s hair cells – and this causes damage.
Unless the sound is extremely loud, it’s unlikely you’ll experience any noticeable change to begin with. Typically, noise-induced hearing loss takes time to occur. In most cases, it happens in both ears simultaneously; though it can happen in just the one ear.
Ultimately, prevention is the key. Once permanent damage has been done to the cochlea, it’s irreversible. Hearing loss can be managed with assistive hearing aids and treatment, but it can never be regained naturally again.
What Are the Symptoms?
Symptoms of noise-induced hearing loss tend to occur very gradually over time. Here are some of the classic signs to look out for.
- Difficulty hearing conversations. This is often the first symptom that sufferers experience; particularly when trying to have a conversation in a noisy location, where background noise levels are high.
- Volume decrease. Most people suffering from hearing loss state that overall, the volume of noises around them seems less audible.
- Additionally, noise-induced hearing impairment can cause noises to lose clarity. For example, certain letters in a sentence might be more difficult to hear than others – notably ‘s’ and ‘t’ in the earlier stages.
- ‘Full’ feeling in the ear. Some sufferers report that their ears feel ‘fuller’ than normal.
- Difficulty hearing background noises. People with hearing loss may find it hard to hear the television or radio, or may struggle to hear oncoming cars when crossing the road.
- Tinnitus is also associated with noise-induced hearing loss. It manifests itself as buzzing or ringing in the ears, though occasionally, this can be heard as whistling, humming, or even singing. It’s very common, and affects one in 10 people in the UK.
What Causes the Damage?
If your hearing loss isn’t due to natural causes, then it’s likely that exposure to high levels of noise is to blame for your condition. Here are a few of the most common causes of noise-induced hearing loss.
- Loud music. Listening to loud music, whether on an MP3 player or at a music venue, can damage your ears. Regularly listening to music at high volumes (over 89dB) for five hours a week or more, can damage hearing permanently.
- Working conditions. Many industries are noisy, and legally, if levels of noise reach 80dB or higher, your employer must provide you with adequate aural protection.
- Armed forces. Those working in the armed forces are at a higher risk of experiencing hearing loss – as noises from jet engines and artillery can reach as high as 140dB. Additionally, being exposed to extremely loud noises (such as bombs detonating) without receiving proper aural protection, can result in immediate, noticeable hearing loss.
Diagnosing Hearing Loss
If you’re experiencing problems with your hearing, it’s important to book an appointment with your GP, who will conduct an initial examination of your ears. During this painless assessment, they’ll check inside your ear, looking for any obvious abnormalities, such as:
- Blockage (for example, excess ear wax)
- A torn or collapsed ear drum
- Infection in the ear canal or middle ear
- Fluid behind the ear drum
- Skin collection in the middle ear (cholesteatoma)
If your GP is unable to determine what’s causing your hearing loss, they’ll refer you to an audiologist or ENT specialist (ear, nose and throat). These doctors will have the necessary equipment to carry out more extensive hearing tests – which will help them to identify the problem, and how badly your hearing has been affected. They’ll also try to ascertain which sort of hearing problem you have; conductive (where the sound is unable to pass easily through the ear) or sensorial (where part of the ear isn’t functioning properly).
There is a range of tests that you might experience. Here are the most commonly used forms of hearing-loss assessment:
- Tuning fork test. When gently tapped, a tuning fork (a y-shaped metallic device) produces sound waves at a specific pitch. The specialist performing the test will gently rap the tuning fork against their elbow to make it vibrate, then hold it at different locations around your head. This will tell them whether or not you have conductive or sensorineural hearing loss.
- Pure tone audiometry. This test assesses both ears. It uses a machine called an audiometer, which omits a variety of sounds at different volumes and pitches. You’ll be asked to listen to these sounds and indicate whether or not you’ve been able to hear them – normally by pushing a button.
- Bone conduction test. This test is used to check whether or not you have sensorineural hearing loss. Your doctor will place a vibrating probe against your mastoid bone, which is located just behind your ear. It’s similar to the tuning fork test but considered a little more sophisticated. It’s often used in combination with pure tone audiometry to find out where in the ear the hearing loss is occurring.
Understanding Your Diagnosis
After testing, your doctor will give you the results. There are four defined levels of hearing impairment.
- Mild deafness. If your results fall within this category, your hearing loss probably won’t impact much on your everyday life. The quietest sound you can hear is 21 to 40dB. If you experience any problems with this level of deafness, it’s likely to be in conversations, and hearing voices against noisy backgrounds.
- Moderate deafness. With moderate deafness, you may find it difficult to hear voices without the assistance of a hearing aid, and other background noises may also prove tricky to hear – such as the television. The quietest noise you can hear is from 41 to 70dB.
- Severe deafness. Normally, when hearing loss is severe, you’ll need to learn to lip-read or use BSL (British Sign Language), even with a hearing aid. The quietest noise you’ll be able to hear is 71 to 90dB.
- Profound deafness. Profound deafness is when the quietest sound you can hear is over 90dB. Again, learning lip-reading and BSL is advisable.
It’s less common to be diagnosed with severe or profound deafness, which currently affects around 900,000 people in the UK. By contrast, over 10 million people suffer with moderate or mild deafness.
Treating Noise-Induced Hearing Loss
If your hearing has been damaged by exposure to noise, it’s highly unlikely to be a conductive hearing loss. This type of impairment is more commonly associated with blockages (such as ear wax build-up), bacterial infection or a perforated eardrum.
Most cases of noise-induced hearing loss are sensorineural – which means that part of the ear is no longer able to function properly. Unfortunately, sensorineural hearing loss is often more complicated to treat, and damage is often permanent.
Here are some of the treatments available to you:
- Hearing aid. This is the most common form of treatment for hearing loss. In fact, about 1.4 million people in this country alone use them. It’s a small device, which is made up of an amplifier, a loudspeaker, a microphone and a battery. Its purpose is to increase the volume of any noise entering your ear, which means you can hear things more clearly. However, they’re not suitable for everyone, particularly those with profound deafness.
There are several different kinds of hearing aid. The most well-known is the ‘over-the-ear’ model, which sits neatly around and behind the ear. However, there are also hearing aids that are worn completely within the ear canal, plus those that sit within the shell of the ear.
- Surgically fitted hearing aids. Your doctor may decide that a different type of hearing aid is more suitable for you, such as one that is bone anchored, and stimulates your mastoid bone. This involves a minor surgical procedure, during which the device is screwed harmlessly to the skull.
- Disposable hearing aids. If your hearing loss is only mild or moderate, you are likely to be given disposable hearing aids – which have batteries that last for around 12 weeks. After this period, they’re then thrown away and replaced.
- Cochlear implant. If your hearing loss is severe or profound, your doctor might recommend that you have a cochlear implant fitted. The device has an external sound processor, plus a variety of internal parts (such as a receiver coil). The sound processor collects the sound, analyses it, then converts the noise into signals, which are sent via an electrode to the cochlea. Due to the fact that this type of device relies on the hearing nerves working properly, it’s unsuitable for those who have suffered nerve damage.
Lip-Reading and Sign Language
If your hearing is severe or profound, then hearing aids will help, but won’t completely rectify your hearing loss. As a result, it’s advisable that you also learn to lip-read or use BSL (British Sign Language). It’s estimated that approximately 24,000 people use BSL as their main form of communication in the UK – with much more who can speak it as a second language.
The process of lip-reading is relatively easy to pick up and involves following the lip-movements of the person you’re speaking to, to gain a better understanding of what words they’re using. BSL is a little harder to pick up, but there are courses online to help you, plus support classes in your local area.
Support After Diagnosis
If your noise-induced hearing loss is severe or profound, you may be entitled to receive certain benefits – particularly if you’re unable to work as a result of your condition.
Additionally, if you believe that your hearing problems are directly related to employer negligence, you may have cause to seek compensation. However, it’s not enough to have simply worked in a noisy environment. In order to make a claim, it needs to be proven that your employer behaved in a negligent manner – for example, not supplying you with the correct protective equipment.
According to the HSE, the following preventative measures should be in place in noisy working environments:
- The employer should obtain noise data relating to their machinery.
- Noise levels should take into account where employees are likely to be.
- Noisy machinery should be moved as far away from employees as possible.
- If it cannot be moved, a sound-insulating enclosure should be used.
- If this is not possible, other measures should be taken to minimise noise, such as using acoustic screens, fitting anti-vibration mountings, and fitting silencers to exhaust systems.
- Ensure workers wear protective equipment when exposed to sounds over 85dB.
- Provide a ‘noise refuge’ wherever possible, where exposure throughout the day can be limited.
Living with Hearing Loss
Thankfully, hearing loss is a manageable condition, and devices such as hearing aids and cochlear implants can improve the quality of hearing significantly. However, if you’re finding your loss of hearing difficult to manage, there are support groups in your area, designed to help you cope with your condition. You can find out more on the Action on Hearing Loss website.