A Report On Hearing Loss Due To Excessive Noise Exposure

Summary

This report provides an insight into hearing loss due to excessive noise exposure. The report explores that hearing damage to the inner ear is possible past 85dBs, how the ear works particularly in how sound travels through the ear. It also looks at that in both the workplace and in public events regulations have been put down so that employees and citizens are not put in danger of hearing loss or damage to their ears. The report also explores how different places, devices and levels affect how people perceive noise and are impacted by it. Work by McCormick et al. (2014) helps investigate how different wave forms are received in the ear, as well as auditory and frequency perception.

Introduction

Hearing loss is when your ability to hear is reduced. Hearing loss can develop by two main factors, exposure to loud noise for an extended amount of time and/or ageing. Noise induced hearing loss is often sensorineural, this is where the problem lies between the inner ear and the brain. The world is a loud environment, in the average everyday life the ear is exposed to a wide range of harming decibels. In this essay on hearing loss the focus will be on noise-induced hearing loss with the following being considered; how we perceive loudness including the structure of the ear and how it can become damaged, places, devices and levels and how these can become factors into hearing loss, the last subject will be the law and how requirements in the workplace and in live music events can help with the effect of hearing loss.

How We Perceive Loudness

The Ear

The ear is split into three main sections, the outer ear, middle ear and inner ear. The outer ear consists of the pinna, which acts as a funnel to direct the sound further intothe ear, and the auditory canal (also known as the ear canal) this sends the sound from the pinna to the eardrum. The final part of the outer ear is the tympanic membrane, more commonly known as the ear drum, this sends the sound vibrations into the inner ear. The middle ear includes three small bones, the malleus, incus, and stapes, that join up to be the ossicles. The malleus joins to the eardrum, which then goes along to the stapes which is connected to the inner ear. The inner ear connects to the middle ear via an oval window, this then connects to the cochlea. The cochlea is fluid filled and contains many hair cells which are vital to hear. When a sound is made the vibrations travel down the pinna, to the eardrum which vibrates, these vibrations are then transferred to the inner ear via the bones in the middle ear, from there the vibrations are sent into the fluid in the cochlea which is where the pressure waves are created, a pressure difference is created across the membrane.

Damage

The National Centre for Environmental Health (2018) state that “The average person is born with 16,000 hair cells in the cochlea” Loud noises can cause the hair cells to bend over causing temporary hearing loss, however, if there is repeated exposure to loud noises then these hair cells may be destroyed, once destroyed they are not repairable. Noise not only damages the hair cells but also can damage the auditory nerve that carries information to the brain.

Loudness

“Loudness is commonly confused with volume. The two terms, however, are entirely different concepts. ’ Award winning audio engineer Brad Pack (2019) says. “Volume is a scientific measurement of the quantity or power of a sound. Loudness, on the other hand, is much more difficult to quantify as it is completely subjective and based entirely on your personal perception of sound. The frequency content, duration, and volume of a sound are all factors in how we perceive its loudness” He continues. Points from this is that loudness is a subjective opinion based off of personal experience, and what we actually perceive loudness is a group of factors together.

Prevention

Hearing protection is important from a young age, if a child is exposed to loud noises, they are susceptible to acoustic trauma, which is an injury to the inner ear. Hearing protection devices can be used to help reduce the noise that is transmitted to the eardrum. By using hearing protection, the impact on the inner ear will be lessened therefore protecting the cochlea and reducing the risk of hearing loss. Devices such as earplugs, noise cancelling headphones and noise isolating headphones can all help protect against the excess sound pressures.

Places, Devices and Levels

Place

The architecture and what sort of building can affect how noise travels and is being transmitted. For example, a study by Walsh et al. (2000) done in San Francisco found that when measuring the decibels of most popular clubs, the loudest was 105 decibels, and the quietest was 94 decibels. The human ear is at risk of damage past 85 decibels. The National Institute for occupational safety and health say that in the quietest club, it would only take up to an hour before people are at risk of hearing damage, at the loudest it would only take 4 minutes. The study by Walsh et al. (2000) is a look into a club scenario, industrial workplaces are also a common place that comes up when discussing noise induced hearing loss, there was an estimated 21,000 numbers with work related hearing loss from 2017 – 2018.

Devices

Victory (2019) discusses the impacts that earphones and headphones can have on a listener. “Most earbuds are low quality, incapable of blocking out ambient noise. They tend to transmit bass poorly. Both of these factors lead listeners to turn up the volume even more” Victory then goes on to talk about safer alternatives to headphones which include noise cancelling headphones, which use inverse waves to cancel out any other sounds, and noise isolating headphones, which create a seal around the ear to isolate the sound, blocking out any unwanted noise. Headphones and earphones that cause listeners to turn up the volume can damage the listeners ears as when the volume is turned up, the decibel increases but also that listener then becomes accustomed to that volume.

Level

“Level is a term with precise meaning. For a real sound travelling in air (or any other medium), its level is measure in terms of sound pressure. Sound pressure is the difference from normal air pressure caused by the sound. ” David Mellor (2006) explains. The higher the sound level, the more likely the noise could damage the inner ear.

The Law

1. Requirements for the workplace In 2006 a noise regulation was put in place to help workers protect their ears from excessive noises at the workplace. The regulation states that any worker exposed to noise of 80-87dB must be provided with a form of ear protection. This did not apply to entertainment or music workplaces as that didn’t join the regulation until 2008, as it was considered that the music industry, noise is purposefully created for enjoyment, whereas in other workplaces, such as a factory, the noise is an excess from the machines. However, it was agreed that it was necessary for the entertainment sector to protect the employees from any damage.
2. Requirements for an event According to the Health a Safety executive (2019) there is no specific legislation setting noise limits for events. However, it also states that no audience areas can be exposed to more than 140dBs, as well as no audience members are allowed within 3 metres of a loudspeaker. And finally, if the event is likely to exceed 96dBs, then the audience must be told of the risk before the event. If an event has pyrotechnics, the same applies that it cannot exceed 140dBs, and the audience must be aware. Some reports mention excessive noise levels in the case of a cinema, when tested by Ferguson et al. (2000) all films were below 80dB, however, they did exceed 90dB but it was only for a few seconds. They found that there was no evidence that cinemas could cause hearing loss.

Conclusion

The report was to explore into hearing loss and how damage to the ear can be prevented. Damage done to the inner ear is usually irreversible, however, if following the correct regulations risk of damage can be reduced. When put into real life circumstances, in my personal experience, hearing loss can be difficult to deal with. A companion of mine did not use hearing protection, through the beginning of his music career, where he was in a wedding band, whilst at the same time producing his own music. His ears soon developed permanent tinnitus, causing him to hear a constant ring. Damage to ears can happen to everyone, and it is important to protect them especially in younger children. As he was in a band he had frequent exposure to loud sound which, without protection, after a while causes pressure on the inner ear, which is what happened causing tinnitus. In the future to protect my ears from any damage I will use earplugs when I know I’m going to be exposed to loud noises and as Victory (2019) mentioned that most earphones have factors that cause listeners to turn up their music, therefore I will use suitable headphones when listening to music.

References

1. Doswell Royster, J. (2017) Preventing Noise Induced Hearing Loss. North Carolina Medical Journal [Online] Volume 78 (number 2), Pages 113 -117. [Accessed 30 October 2019]
2. Ferguson, M. Davis, A. Lovell, E. (2000) Cinemas – do they pose a risk to hearing? Noise Health [Online] Volume 2 (Issue 8), Pages 55-58 [Accessed 30 October 2019]
3. Health and Safety executive (2019) Noise [Online] Available from: http://www. hse. gov. uk/event-safety/noise. htm [Accessed 30 October 2019]
4. Health and Safety executive (2019) Noise induced Hearing loss in Great Britain [Online] Available from: http://www. hse. gov. uk/statistics/causdis/deafness/index. htm [Accessed 30 October 2019]
5. McCormick, T. Rumsey, F. (2014) Sound and Recording Applications and Theory. 7th Edition. New York and London: Focal Press. Mellor, D. (2006) What is the difference between level, volume and loudness? Available from: https://www. audiomasterclass. com/newsletter/what-is-the-difference-between-level-volume-and-loudness [Accessed 30 October 2019]
6. National Center for Environmental Health. (2018) How does loud noise cause hearing loss?. Available from: https://www. cdc. gov/nceh/hearing_loss/how_does_loud_noise_cause_hearing_loss. html [Accessed 28 October 2019]
7. Pack, B. (2019) What is loudness? Tips and Tricks [Blog] 05 June. Available from: https://www. sonarworks. com/blog/learn/what-is-loudness/ [Access 28 October 2019]
8. Statutory Instruments, Work and Pensions (2005) Control of Noise at work regulations [Online] London. (Number 1643) Available from: http://www. legislation. gov. uk/uksi/2005/1643/signature/made [Accessed 30 October 2019] Victory, J. (2019) How to prevent hearing loss from headphones and earphones. Available from: https://www. healthyhearing. com/report/52503-Headphones-when-hearing-danger-is-closer-than-you-think [Accessed 30 October 2019]
9. Walsh, E (2000) Dancing Till Deaf. The Noise Center [Online] Volume 25 (number 1) [Accessed 30 October 2019]