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T
fhese web pages are on the subject of "Random Effective Deafness", or, R.E.D. (also
known as being deaf on one side, or Unilateral Hearing Loss). At the moment these pages are
geared to my own personal experiences and conclusions, and I write these notes with the hope
that they may prove useful to others with this condition. My own situation is that I have been
completely deaf in my left ear as a result of an accident some years ago but the hearing in my
right ear was unaffected. My notes and conclusions are based on my own experience, hence they
may not be entirely universally true. In particular, I gather that some people who have lost their
hearing have some hope of returning to a binaural state through various sorts of hearing aids. In
my case, I am hopelessly monaural.
M
uch of the discussion here I have learned from observation over the years, and my
motivation in writing these webpages is that I think I would have been much better off in life if I
had known some of these facts earlier on. There is also a dearth of information about the
condition, insofar as I can find it. A google search on most medical conditions generally provides
a host of relevant, usually reliable, webpages, but not so RED/UHL. The two main goals of these
pages are: (a) by understanding the various issues, there may be less stress and mystery about the
situation (e.g., if one runs screaming from a noisy room, it is normal, not because there is
something flawed about your personality) and (b) by understanding the various issues, one can
then develop strategies for dealing constructively with the various problems.
Please note that I am not medically qualified. I also do not claim 100% complete and thorough
accuracy on these pages; opinions, ignorance, and misinformation may sneak in, but I try to
avoid that.
Random Effective Deafness - Accoustical Theory
Broadband beamforming is not possible with one ear.
P
eople with two working ears are able to "beamform" sound. This means that when sound
arrives at their ears, the brain can use the phase difference between the signals of the two ears to
do several remarkable things. First, and obvious, the sound can be localized. The binaural person
is able to tell from what direction the sound comes from and how far away the source is. But, the
binaural signal can be used for far more that that. "Broadband beamforming" means that all
frequencies of sound are beamformed, so that the various frequencies contribute independent
information about the signal. This process also allows the binaural listener to exclude "noise",
here defined as anything other than the signal of interest. This means that in a crowded room, a
binaural person can hear the person they are talking to, while simultaneously excluding the
voices of the surrounding mob of talkers to a large extent. The binaural person can hear the
conversation.
I
n contrast, a monaural person hears only one channel of the acoustic signals. No localization
or beamforming is possible. All the sound signals come in as one jumbled signal, and no
separation of those signals is possible. The difference between binaural and monaural is
profound. The monaural person can barely hear the conversation in a crowded room - by using
the larger signal of the nearby talker, or by unique frequency characteristics of voices.
Localization of sound is not possible, so that when people see me at a distance and call out to
me, I do not know where they are calling from - a 360 degree search for the signal must then be
conducted (or I will just sit on the curb and wait for the caller to get closer.)
"Barely hear the conversation" means that only fragments of sentences or words are
comprehended, and these must be sorted from noise or any other fragments of sentences or
words from nearby conversations. The brain must work hard to comprehend the meaning of the
sentence based on those fragments, and the context of the conversation.
Much of this discussion falls under the category of the topic of "psychoacoustics," a surprisingly
challenging issue to understand; research is ongoing. For more technical information, see this
article in Physics Today: "How we localize sound". Most of the discussion on psychoacoustics is
irrelevant to those of us with unilateral hearing loss!
The noisy room problem.
A
room filled with people talking has the property that as more people talk the noise
increases. And as the noise increases, people talk louder, which increases the noise, etc. Pretty
soon people are talking quite loudly, yet still hearing about as well as they did when the meeting
started and everyone was whispering to each other. This scenario is basically a nightmare to a
monaural person...
Acoustic shadowing.
D
eafness on one side of course means that sound coming from that side will
not be heard. This is actually rarely the case, because reflected sound will most often reach the
good ear. With practice and intuition, a monaural person can often tell which direction the sound
is coming from by using the natures of the sound and the environment. The notion that someone
with SSD is in danger of being, e.g., hit by a car from his/her deaf side is rather overblown.
Acoustic reflection.
W
hile in some circumstances, reflection of sound from environmental surfaces can help
a monaural person, in some circumstances this can be a hindrance. A monaural person seeks to
place himself in the right place and in the right orientation to best hear the sound of interest,
while excluding the noise. Sometimes this involves aiming the good ear at a single reflective
surface to enhance a signal, e.g., at a booth in a noisy restaurant, the good ear towards the wall is
preferred. In a noisy, acoustically-reflective environment, the sound will seem to originate from
all directions, defeating the strategy. This is the case with the noisy, echo-y cafe's that seem to be
all too popular these days. Echo-y here means spaces that have great reverberation, i.e.,
reverberative environments present an added difficulty to the unilateral hearing person.
Random Effective Deafness - Social Effects
First impressions...
P
eople with unilateral hearing loss often behave in ways that allow them to cope better,
either consciously or unconsciously. This behaviour can seem strange to others, even if it may
not be recognized as such. However, I've wondered about what sort of impression I leave on
people I am just getting to know, and how that affects the relationship. I think in some cases the
effect can be substantial.
The turning head.
I
t quite frequently happens that as I turn my head to hear a soft-spoken person better, or to
hear better in a noisy environment, the person I am talking to will also turn their head. This
seems to be one of those curious subconscious social cue things that goes on. What various
people think of this, I could not say, although one person mentioned that it seemed to make me
look "thoughful".
Around in circles.
A
corollary to The Turning Head occurs sometimes when standing in a conversation. If I
turn my head to hear better, the person I am talking too will start to move to his right to face me
directly. I of course turn my head some more to hear him, and pretty soon we are slowing turning
in circles. I've taken to stopping the conversation, telling the person that I am deaf in one ear and
asking them to stop moving to their right. Honesty is the best policy.
Social gatherings: The noisy room.
W
hat a nightmare, and it doesn't even have to be that noisy. Beware also of noises such
as from overhead projectors, traffic, or even the high-frequency whine of televisions (that most
people can't even hear) - these noises are also fairly destructive of conversations. More later.
Choosing where to sit.
I
will most often completely ignore the person sitting on my deaf side. It is very difficult to
carry on a conversation, e.g., at a dinner party. I will sometimes just turn to the person on my left
and apologize for ignoring them up front and explain the situation. People are understanding if
they know what is going on.
Random Effective Deafness - Cognitive
Consequences
I
believe that in noisy environments, much more happens that just not being
able to hear properly. The situation is not that I can just stand there in the noise
and be happy, if deaf. A definite, unconfortable mental confusion or stress sets in,
that really rather forces me to leave the environment. This seems to me almost a
neurological effect. In noisy, crowded rooms, I get an instant and dramatic sense
of relief by plugging up my ear and being completely deaf - in such environments
I am practically deaf anyways.
N
oisy environments can be fatiguing, although I am sure this is true for
anyone. I used to get quite tired flying on airplanes, but now I use earplugs (well,
an earplug) regularly which helps considerably. Similarly, on long drives, in my
previous older noisier car, I used to get fatigued, arriving rather exhausted. An
earplug while driving is perhaps not altogether safe, but on 8 hr. interstate drives
it certainly helped with the fatigue. My newer car has quite good sound proofing,
which has made a world of difference. I am sure this fatigue is related to the stress
of a noisy environment, noted above.
Random Effective Deafness - Hearing Aids
T
he hearing aids for monaural people generally aim to move the sound from
the deaf side over to the hearing side - one still hears in mono, but the sound can
originate from both sides of the head. I don't believe such hearing aids are for me,
but I include a bit of discussion here (mostly to keep educating myself). See
below a recent letter to Hearing Dogs for Deaf People for additional information.
Random Effective Deafness - Nuances
Stereo Headphones
S
o, you have your new walkman, new mp3 player etc. and you go to listen
to music and what happens? It is a stereo headphone...this means you are
supposed to get the piano in one ear and the bass in another ear. But those of us
who can hear in only one ear can hear the piano OR the bass, but not both in this
situation. What a pain. These things are mass marketed, and there is rarely a small
switch to get just plain mono. The easiest solution is just to get one of the
monaural headsets that are readily available these days - these are used for talking
on the telephone, VOIP, etc. They naturally combine stereo signals into mono.
A
possible solution is to obtain an in-line amplifier that is designed to
produce a mono signal from a stereo input. People keep telling me that the
solution is to use software, i.e., a mixer, to obtain mono; but I've not been able to
figure out how to do that with the mixers I have available. This should be the
simplest of all mixer tasks...