DAMAGE TO HEARING from exposure to noise remains a common problem in the 21st century, despite the regulation of occupational noise exposure in most developed countries.
In the UK, approximately 170,000 people suffer deafness, tinnitus or other ear conditions as a result of exposure to excessive noise at work. The resulting hearing loss cannot be cured, but is preventable.
Exposure to excessive noise levels leads to a temporary hearing impairment which can go on to become permanent if noise exposure continues. The damage depends both on the level of noise and its duration. It is thought that equal ‘doses’ of noise will cause the same degree of damage. Therefore exposure to high intensity noise for a short period may cause the same damage as prolonged noise at a lower level if the ‘doses’ are equivalent.
Damage from excessive noise exposure typically affects the ability to hear some of the higher frequencies first, e.g. at 4Kz, but as exposure continues, the ability to hear other frequencies is also affected. The hearing loss may not be noticed in the early stages but as the hearing worsens, individuals usually complain that they have difficulty understanding speech, especially in the presence of background noise. The hearing impairment
is often associated with the development of tinnitus, which itself can be as disabling as the hearing loss.
The ageing process also affects hearing and it is important to take this into account when assessing the causes of hearing loss.
The Control of Noise at Work Regulations (2005) which came into force on 6th April 2006, and which supersede previous regulations, govern the limits of noise exposure on a daily or weekly basis and also advise about the provision of hearing protection in the workplace. (see http://www.opsi.gov.uk/si/si2005/20051643.htm). If the recommendations of these regulations are adhered to, damage to hearing from exposure to excessive noise should become a thing of the past.