Noise Induced Hearing Loss

The Alarming Increase in Noise-Induced Hearing Loss

  While it may be true that the pair of facial appendages known as ears are not necessarily the most attractive of everyone’s features, a journey along the auditory canal reveals a structure of delicate beauty and precision beyond the tympanic membrane, in the middle chambers of the auditory system. Known as ossicles, the triad of tiny bones, consisting of the descriptively-named maleus, incus and stapes, or hammer anvil and stirrup, is responsible for conducting soundwaves to the inner ear. It is the latter chamber, however, that holds the secret of how these soundwaves are converted into the nerve impulses that are then relayed to the brain for interpretation. Within the snail shell-shaped, fluid-filled cochlea, specialised cells, with delicate hair-like protrusions, generate these impulses when disturbed by vibrations in the cochlear fluid. Consistent and prolonged exposure to excessively loud sounds, however, can cause irreversible damage to these hair cells, resulting in noise-induced hearing loss.

At one time, the number of those who would have been at greatest risk of this condition would have been relatively limited. High-risk individuals would have mainly consisted of those workers required to operate heavy machinery, such as jackhammers and heavy-duty drilling equipment, as well as armed forces personnel constantly subjected to the sound of gunfire and explosions in combat zones. Over the years, however, our environment has become a lot noisier with the introduction of jet aircrafts, the steady growth in road traffic, and the apparently insatiable need to play music at volumes sufficient to damage concrete.

To describe the hair cells that line the cochlea as delicate is no exaggeration. A normal conversation will result in a sound level of around 60 decibels, while a whisper generates only about half of that figure. Sustained exposure to sound levels of just 85 decibels is sufficient to permanently damage those cells. Given that the average hairdryer operates at around 100dB and a petrol-driven lawnmower, slightly higher, most of us are actually at risk of developing noise-induced hearing loss.

The effect is a cumulative one in which each additional exposure serves to compound the existing damage. If such exposures are allowed to continue, the result can be profound sensorineural deafness for which, in many cases, a conventional hearing aid will offer no significant correction. In such circumstances, a cochlear implant may be the only viable option to help manage the condition.

That this type of auditory impairment is clearly on the increase, and has now begun to affect children of primary school age in many countries, is not only worrying because it is irreversible, but also because it is a condition that can be avoided with a few simple precautions.

While almost everyone living in South Africa’s busy urban areas is at risk to some degree, their exposure tends to be intermittent. In practice, it is those employed to work for eight hours a day in the noisy environment of some factory production line or underground on our mines that continue to experience the greatest risk of noise-induced hearing loss. For them, a suitable pair of earplugs and a little self-discipline could mean the difference between retiring on a workplace pension, and seeking compensation for an industrial injury that could result in a life of silence.

Forget about popping around to the local Dis-Chem or Clicks pharmacy for a few pairs of disposables. They may help muffle your partner’s snoring, but won’t cut it on the factory floor. The type of protection necessary will not only require a product individually tailored to fit the contours of both left and right ears precisely, but must also permit the wearer to conduct a conversation without compromising his or her safety. Comfort is also important, as an ill-fitting, uncomfortable plug may prompt the wearer to remove it, which further underlines the need for a tailored unit made from soft and pliable material.

Along with its advanced Noise-Ban range of earplugs designed to tick all of the above boxes, H.A.S.S. Industrial offers a specialised hearing protection programme. Beginning with a needs assessment, the programme proceeds to take impressions of the ear canals of employees, and to manufacture the custom-made plugs. Next, they are fitted, checked for comfort and leaks, and the built-in attenuator adjusted to strike the balance between protection and ease of communication.

Awareness education and user training, data recording and annual monitoring complete this comprehensive and effective programme of protection against noise-induced hearing loss.

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