dzapala at aol.com
Sun Oct 12 00:29:06 EST 1997
When people think of hearing loss, they typically think in terms of difficulty
hearing soft sounds. However, damage to the inner ear may also affect a
persons ability to tolerate moderatly loud sounds. This is a well known
phenomina termed recruitment and can be reasonably modeled mathematically
based on the amount of hearing loss (inner ear damage) present. We now think
there is more to it than just inner ear damage. It seems that the brain may
play a role in changing the perception of loudness of some sounds. Jastreboff
and others believe that this brain effect plays an important role in the
development of tinnitus and in the percept of sounds being abnormally loud
when hearing sensitivity appears normal (no hearing loss, not very much inner
ear damage). Now if this is true (and I believe it is) there is a problem.
When someone has a hearing loss and has a problem tolerating loud sound, is it
from recruitment (inner ear effect) or from a change in brain function
(hyperacusis effect). The answer is probably both, with the relative amount
of each varying on a case by case basis.
In your son's case, I have a hard time thinking his problem is hyperacusis,
given the amount of hearing loss present. But I know I don't know much in
this area (and it is a research interest of mine). I have seen patients with
severe to profound hearing loss and very limited dynamic range (the difference
between the softest sound detected and the loudest sound
tolerated....sometimes as small as 5 dB. Here are some questions for you. 1)
do you, your audiologist or physician notice any unusual eyemovements or head
tilt with loud sounds? 2) any obvious dizziness with loud sounds? 3) Does
your child startle to unexpected sounds and how often, or does he or she just
complain about their loudness?
There is a great deal we do not know about hearing and loudness perception.
There is much progress on the research side of the problem. Eventually this
will improve our ability to treat patients clinically.
Best wishes and good luck
>When we first noticed that our son was having trouble with hearing
>sensitivitywe had his UCL's tested by audiologists...because our son has
>a moderate-profound hearing loss and his UCL's were at his hearing
>threshold, many audilogists thought that the tester made a mistake...He
>was observed having difficulty in certain loud noises plus was tested
>with consistant results with very low UCL's..........It is that
>audiologists are not familiar with hyperacusis or what....I am very
>thinkful that we were told by an audioloigist in Tx. that she thought our
>son's condition was hyperacusis and she refered us to Maryland Jastreboff.
>...I would like to hear from audiologists and what the deal is?????
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