Hearing loss and its causes – Part 1
Hearing loss is something that will affect all of us at some point in our lifetime and can be defined as a partial or total inability to hear. If you have a hearing loss, you may be referred to as a person who is “hard of hearing”. A deaf person on the other hand, has little to no hearing.
So what causes our hearing to deteriorate? There are a number of factors that can cause our hearing to decline either over time or suddenly.
Presbycusis is the technical term for age related deafness; a hearing loss that gradually deteriorates over time as we grow older. As our hearing deteriorates slowly, we do not realize that our hearing is gradually getting worse. Often we complain that kids of today “don’t talk properly” or that “people mumble”; children or female voices are more difficult to understand, and situations where there is background noise makes understanding conversations challenging, if not impossible.
Most often, it is the high pitched sounds are affected. It is the high pitches in our speech which allow you to “hear” conversations, however you don’t always “understand” what was said. You may also not hear the phone or door bell ringing, or hear the indicator in the car. Many people will also experience ringing or buzzing sounds in the ears, which is referred to a Tinnitus.
A presbycusis hearing loss is generally sensorineural in nature, meaning that there is nothing medically or surgical that can be done to “fix” the hearing loss. For most, hearing aids are a great solution to improve understanding of conversations both in quiet and noise, as well as easing the impact of tinnitus that you may otherwise experience.
It has been suggested that at least half of all hearing losses are as a result of some degree of noise exposure. Everyday, we are exposed to varying degrees of “noise” whether it be from the washing machine, TV or screaming children. Noise which can be harmful to our ears is when it is too loud. Either for a brief time such as a gunshot, explosion, nail gun or short, sharp repetitive sounds or loud and long lasting sounds from a tractor, jackhammer, factory or workshop.
Under the Australian Standard for Occupational Noise [NOHSC: 1007(2000)], exposure to noise in the workplace is an 8hr equivalent continuous A-weighted sound pressure level of 85dB(A). This level is taken at the employee’s ear level without the use of hearing protection.
So what does this mean? Essentially if you work in an environment where the noise level exceeds 85db(A), you should be wearing hearing protection whilst in that environment. Further more, for each 3dB increase in noise levels above 85dB(A) the amount of time you can safely work in that environment is halved. For example, if the noise level is 97dB(A), you can only work in that environment for 30 mins.
Below are some examples of average decibel ratings for familiar sounds–
Quiet radio music – 40dB
Normal conversation – 60dB
Noise from heavy traffic – 80dB
Lawn-mower – 90dB
Chainsaw – 110dB
Rivert Hamer (pain can be felt at this threshold) – 130dB
Jet engine at 30m–140dB
As you can see, using your lawn mower and whipper snipper on the weekends has the potential to harm your hearing. Avoid loud noise where possible, and if you can’t avoid the noise make sure you aren’t too close to the noise source or in the vicinity for too long, and wear hearing protection to protect what is left of your hearing – even if you already have a hearing loss. Hearing aids will only work with what is left of you hearing; hearing aids don’t replace your hearing.
In Part 2 of this feature, we will look at other causes of hearing loss including genetics, physical trauma, medication and chemicals.