Speech intelligibility in senior citizens.. [long]

Jes og Janet jajo at post12.tele.dk
Mon Oct 22 03:34:32 EST 2001


Dear Richard

The problem you describe has been a main focus point in a big audioligical
study performed in cooperation between Oticon's research center, Eriksholm
and Professor Stuart Gatehous at the University in Glasgow. Some of the
details of the study can be found at the Glasgow university website.

Some of the results in short:
The cognitive capacity of our brains are reduced as we get older, especially
after 70 the effect is clear in most people. Cognitive capacity (short term
memory as one example) has been shown to have an impact on how well we
understand speech in different situations, no matter whether we have a
hearing loss or not.

This effect may be what you experience in the case of your mother.

Best regards

Jes Olsen
Director of Business and Product Development, Oticon A/S


Richard Howe <basstalk at richardhowe.demon.co.uk> wrote in message
news:pgpmoose.200108160014.9082 at net.bio.net...
> Hello all,
>
> I am looking for some help, or a pointer to a source of help, for a
problem
> that seems not at all straightforward.  Sorry to all those who hate
> cross-posted messages.
>
> I am trying to improve the intelligibility of speech for my mother who is
> now 88.  She has had a gradually worsening high frequency loss for many
> years but only in the last 3 years has this been a problem for her.
> Interestingly the problem came into focus by accident when she told me
that
> the top notes on an electric piano I had loaned her seemed not to be
> working :-)
>
> Without detailing her audiogram at this stage, she has hearing in the
lower
> third of  'normal range' below 650Hz in her right ear and then a sharp
30dB
> fall-off followed by a progressive hf loss from around 900Hz.  Her left
ear
> is similarly 'normal' below 1350Hz and then follows the same pattern as
the
> right - a sharp 30dB fall-off followed by progressive hf loss.
>
> She has two NHS bte analogue aids which have been adjusted to an optimal
> setting [albeit this is still only a crude approximation to the correction
> her audiogram indicates]  They do not help her at all with speech
> recognition and are a constant frustration to her in consequence of which
> they are little used.  Last year I purchased for her a good pair of Beyer
> circumnaural open headphones which she uses with both the tv and radio.
> These delight her because without any frequency correction at all and with
> a very moderate volume level they
> allow her to understand all but certain poor movie soundtracks.  They
> improve her speech intelligibility far more than they ought to and far
more
> than I can account for in any conventional mechanistic sense.
>
> Now comes the problem I am wrestling with:  having tested her extensively
> with recorded speech from radio and tv I have been unable to determine the
> common factors making an individual either easy or difficult to
understand.
> Low pitched, slow speaking, clearly articulating males would be expected
to
> be the easiest and in many cases are but not consistently so.  Similarly,
> high pitched fast talking females would be expected to be difficult and
> usually are but again not always.
>
> I am an EE by training and had an interest in all matters audio all my
> life.  I have tested my mothers hearing extensively and have a very
> detailed audiogram for her.  I have corrected a number of 'difficult'
> speech samples with FFT on my computer to exactly correct for her hearing
> loss.  This does not seem to help and I am left wondering why when speech
> is corrected such that the frequency response matches 'normal' across the
> speech spectrum [below 6000Hz] it is not perceived as normal by the person
> with the hearing loss.
>
> Could it be that a gradual hearing loss, particularly in older people, is
> accompanied by a loss of ability in the brain to interpret the incoming
> stimulus?  Clearly my mother can hear the high frequencies in the
corrected
> speech samples because she asks me 'what are all those funny clicks' to
> which I reply those are all the consonant 't', 'c' and 'p' sounds that you
> cannot usually hear.
>
> Any advice on how to pursue this would be much appreciated.
>
> Richard
>
>





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