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Noise exposure |
Since exposure to noise is cumulative like
exposure to radiation, the longer you are exposed to noise and the
louder the noise, the worse the eventual hearing loss will become. In
addition there is some genetic predisposition to hearing loss caused by
noise exposure, so if your parents or grandparents have a hearing loss
you may develop a hearing loss where your co-worker may not.
We are surrounded by noise in nearly all areas of modern life. Our ears are delicate and
complex structures that are easily damaged. We are exposed to noise at
work, to traffic noise in the street and when we listen to music or go
to night clubs or concerts where the volume is excessive.
A continuous noise level of 85 dB will result in hearing damage over an
8 hour work day. This is
the sound level of heavy road traffic. Compressed air hammers have a
sound level of about 100 dB and rock concerts almost always reach
110-120 dB – the same sound intensity can easily be produced in
headsets when you listen to your stereo or in your car.
Noise exposure and intense sounds cause two main types of hearing loss.
They are called temporary and permanent threshold shifts
Temporary threshold shift is experienced as a temporary dullness
in your hearing after exposure to loud noises. Your hearing will
subsequently recover – depending on how loud the noise have been and
how long you have been exposed to them, there may be some permanent
damage.
Permanent threshold shift is usually experienced 48 hours after exposure
to excessive noise. Permanent threshold shift can occur if you for long
periods of time have been regularly exposed to excessive noise, like on
the job. It can
also occur if you are exposed to very high sound levels for a short
period of time. This type of hearing loss will normally continue to
increase for up to five years after exposure to the noise ceases.
Often permanent hearing loss can occur later in life long after noise
exposure has ceased. Typically, this will manifest it self as a hearing
loss over the age of 50 when the exposure occurred in the early adult
hood. We regularly see patients with a typical noise induced
configuration now in their early 50's who's only exposure to noise
happened as very young adults.
Excessive exposure to noise and high sound levels can also result in Tinnitus
- a constant sound in your ears or head.
