Noise-induced hearing loss (NIHL) decreases your ability to hear or understand speech and sounds around you. It can be caused by a one-time exposure to an intense “impulse” sound, such as an explosion, or by continuous exposure to loud sounds over an extended period of time, such as noise generated from a regular trip to the stadium to cheer on your favourite team!
It can affect both ears or just one, and loud noise doesn’t just impact on your hearing it can also cause tinnitus.
How do we hear?
We hear sound because of vibrations (sound waves) that reach our ears. We recognise these vibrations as speech, music or other sounds.
The outer and middle parts of the ear are involved in amplifying sound from our environment before it reaches the inner ear.
The outer ear is made up of the ear itself and the ear canal. The sound waves travel through the ear canal to reach the eardrum.
The middle ear comprises the eardrum and three tiny bones in the middle ear.
The inner ear contains a snail-shaped structure filled with a fluid called the cochlea. Sound vibrations create waves in the cochlear fluids. As the wave’s peak, they cause tiny hair cells to bend, which converts the vibrations into electrical signals in the auditory nerve.
The auditory nerve carries the electrical signals from the inner ear to the brain which interprets the signals as the sound that you recognise and understand.
Do many people have Noise-Induced Hearing Loss?
Noise-induced hearing loss (NIHL) is a relatively common condition that affects approximately one in seven people in Australia. In 2005, Access Economics estimated the prevalence of hearing loss to be 2.6 million people, or 12.9% of the population. By 2017 this had increased to 14.5% of the population.
The most upsetting thing about this statistic is that almost half (49%) of childhood hearing loss is preventable, as is over a third (37%) of adult hearing loss. The financial costs of hearing loss in 2017 were estimated at $15.9 billion in Australia.
A study conducted by Deloitte into the ‘Social and Economic Cost of Hearing Loss in Australia‘ (2017) is a very confronting read when we know how much of this is avoidable.
Australia is not alone in our ability to damage our hearing! The US Department for Health and Human Services have conducted their own study in 2017 – ‘U.S. Adults Aged 20 to 69 Years Show Signs of Noise-induced Hearing Loss‘ which found that at least 10 million (6 percent) of adults in the U.S. under 70—and perhaps as many as 40 million adults (24 percent)—may have NIHL based on evidence of noise notches in their hearing test results. In the U.S. adults aged 20 to 69 years show signs of noise-induced hearing loss.
So what causes Noise-Induced Hearing Loss?
Sound level is measured in units of decibels. In general, sounds that are less than 80 decibels are safe and won’t damage your hearing even after prolonged exposure. Between 80 and 90 decibels sound can be tolerated but, after 8 hours can have an impact on your hearing. The closer you are to 90 decibels the greater the impact.
Once you are over the 100-decibel level the impact is greater and is only safe for a maximum of 15 minutes.
‘How Loud is Too Loud?’ Infographic by EarQ
What are the symptoms?
Often people are exposed to loud noise over a prolonged period of time so their hearing loss is slow and gradual. Since it’s gradual it can be harder to notice and as a result, may go unnoticed. This can often lead to further exposure of loud noise resulting in even greater hearing loss.
Below is a list of symptoms you may experience if you have NIHL:
- Tinnitus (ringing, roaring or buzzing in your ear or ears)
- Temporary hearing loss that disappears after a few hours
- Sounds that are muffled or distorted
- Difficulty in understanding speech
- Difficulty hearing a conversation when there is background noise
How does noise damage my hearing?
NIHL is actually caused by damage to the delicate hairs inside the inner ear from excessive exposure to loud noise. The average person is born with around 16,000 hair cells within their cochlea. These cells allow your brain to detect sound. Up to 30% to 50% of hair cells can be damaged or destroyed before changes in your hearing can be measured by a hearing test. By the time you notice any hearing loss, many cells have been destroyed and cannot be repaired.
What can I do to prevent it?
- You can make “hearing health” a part of your lifestyle. Stay away from loud or prolonged noises when you can. Turn down the music volume. Buy power tools that have sound controls.
- When you must be around noise, either at work or at play, use something to protect your hearing.
- Hearing protection devices, like earplugs, earmuffs and canal caps, are sold in drugstores/pharmacies and hardware stores. Different brands offer different amounts of protection. If you are not sure which kind is best for you, or how to use it correctly, ask your doctor. Often the best kind is the one that you feel comfortable in so you can wear it when you need it.
- Keep your hearing protectors handy and in good condition.
- Teach your family how important it is to stay away from too much noise and to use hearing protection.
- If you think you have a hearing loss (or if someone in your family thinks so), it is important to have your hearing tested.
