steve sulis wrote:
> FWIW, I recently suffered some inner-ear damage due to a virus ?
> specialists don't definitively know yet. At 1st I was completely deaf
> in the left ear. Gradually the sound is coming back. I now get the
> following properties in my perception of sound :-
> Low freqs(<1000Hz) + High freqs(>3KHz) are ok ( well, as good as they
> ever were)
> Mostly silence from 1KHz -> 2.2KHz, but strong peaks of response at a
> few spot frequencies.
Cochlear implants are sometimes effective in treating cases like yours.
The damaged area of the ear is connected to the auditory system with
miniature wires, and although the connections are initially random, the
ear learns to make sense of them after a while. The brain's ability to
compensate for internal damage is remarkable - stroke victims can often
re-learn how to use their limbs if the part of the brain that deals
with them has been damaged.
> The weidest thing is hearing the same pure sinewave a different
> frequencies depending on whether I use the right ear or left ear. The
> difference is like C to F# in the same octave.
> The above figures are not exact, but are roughly what I get.
There are several possible reasons for that, perhaps the rate that the
haircell synapses are firing, or the time it takes for the synapses to
'recharge their batteries', has been affected by the virus and is
different in your damaged ear.
> I had always imagined that perception of frequency would be invarient
> from left to right ear, but now I know better.
The following experiment gives a quite amazing result: take two simple
tunes, the first consisting of ascending notes and the second
consisting of descending notes. Make two further tunes, each
consisting of alternate notes from the original tunes - these both
sound like a sequence of random ups and downs without any meaningful
'tune' to either of them. If these two 'non-tunes' are played to the
ears through stereo head-phones, the brain magically sorts them out and
hears the two original melodies, and the listener hears the ascending
tune as coming from one earphone and the descending tune as coming from
the other! Furthermore, if the stereo head-phones are then reversed
left/right, the listener hears the two melodies in the same ears (left
or right) as before - the brain has learnt to sort out the sound in
that particular way on the first hearing, and interprets what might
otherwise be confusing information the same way on subsequent hearings.
I suppose its something to do with the brain's response to perceiving
two threatening noises simultaneously, one on the left and the other on
the right. The brain seems to correctly decide where the sounds are
coming from at a higher priority than correctly identifying what the
sounds 'are'.
