One of the first things people
with hearing loss observe is “I hear people fine, but I don’t understand what
they are saying.”
This is a consistent complaint of individuals
who are experiencing the effects of a “sloping high frequency hearing loss.“
WHAT’S HAPPENING AND WHY DO SO MANY HAVE THIS COMPLAINT?
Hearing loss involves not only our ears, but
also our brain: where sound waves are coded by the ears and then translated
into meaningful words. While hearing loss can present itself in varying degrees
of severity in different frequencies, a very common progression of inner ear
hearing loss is sloping high frequency hearing loss.
We commonly measure hearing from 250 to 8000 Hz.
Individuals with “high frequency” hearing loss have no loss at frequencies
below 1000 Hz (lower pitched frequencies), but have abnormal results in the
range of 1000 to 8000 Hz (higher pitched frequencies). High frequency hearing
loss is one of the most common variances of hearing loss there is.
DIFFERENT SPEECH SIGNALS PRODUCE DIFFERENT FREQUENCIES
When examining human speech signals, we see that
there are lower pitched sounds or vowels (A, E, I, O and U) and higher pitched
sounds or consonants (S,F , Th, Sh, Ch, K, P and H). Being able to hear vowels
in the lower pitched frequencies gives us a sensation of hearing speech, but
not being able to hear higher pitched sound or “consonants” is what compromises
our ability to understand full words. (So we hear, but we don’t understand.)
The high-pitched frequencies where consonants
occur is where the discrimination of different words happen. When we have
high-frequency hearing loss, we lose the ability to hear the “consonant” sounds
efficiently and, thus, our ability to tell the difference between words such as
‘Cat” or “Hat”.
KEY SOUNDS AND LETTERS AREN’T HEARD CLEARLY
Imagine having a book with every S, F, Th, Sh,
Ch, K, P and H erased. You could read part of the book and understand some of
it, but you would not be able to understand many key words and phrases and, as
a result, be challenged to understand it. This is what is happening with a high
frequency hearing loss. You can hear part of the message, however your high
frequency loss has “erased” the key sounds or letters needed for discrimination
and understanding.
Luckily, high frequency hearing loss can usually
be helped with proper diagnosis and appropriate amplification.