By Manfred Stoifl (Hearing aid Acoustician) AAHA, Vienna, Austria
Hearing disability is the effect of hearing loss and can have many forms and ramifications
Different
forms of hearing loss result in different hearing disabilities. However, all
hearing losses have one thing in common, that the ears ability to convert
sounds into electrical stimuli or to transmit said stimuli to the brain, is
impaired.
Understanding
the meaning of sounds and the ability to quickly and subconsciously work with
information from the ears is a learned / acquired ability. This fully automatic
and subconscious process is strongly depended on clear and full spectrum auditory
input in the form of electrical stimuli,with as high a resolution as possible coming
from both our ears and continuous practice throughout our life.
A hearing
disability arises when our brain cannot assign meaning to stimulation coming
from the ears. This could be due to a fault in the ear, the conduction from the
ear to the brain or the brains inability to quickly and accurately assign
meaning. Most likely it is a combination of all 3 factors and time. The less
resolution a signal has, the more complex is the brains task to assign a unique
meaning to it.
Initially
hearing loss will not result in a disability, but might just manifest itself by
the environment slowly becoming less noisy as some of the very soft sounds
becoming inaudible. This however means that the auditory centres in the brain
are deprived of crucial input. Over time the degree of hearing loss increases
and the amount of information provided to the brain degreases. This causes our
central processing to become less fast and less accurate due to the lack of
training.
Initially
this manifests itself by understanding some people less good in noisy or
adverse acoustic environments, or by tiring more easily while listening under
such circumstances. As time progresses with or without an increase in actual
hearing loss the brain gets slower and worse processing sounds. A problem which
initially was only present under certain adverse listening conditions becomes
more and more apparent.
It is a self-perpetuating
vicious cycle feeding on itself. The less we hear the less our auditorycentres
in the brain get to work the slower and less accurate they get. The slower and
less accurate they get, the more a hearing disability become apparent and
affects daily life and communication.
Over time,
more and more “brain power” needs to be assigned to the process of assigning
meaning to sounds, and a process which was supposed to work subconsciously
suddenly happens in our consciousness. At that stage one tries to reduce the
effect of the hearing disability, at first rather successful, with contexting.
This is of course very inefficient and tiring way of hearing and drives people
gradually to avoid conversations altogether.