The Bizarre World of Extreme
(or Low Frequency) Hearing Loss
(short, abridged version)
(Click here to read the complete, unabridged version)
© April 2007 (latest revision August 2007), by Neil Bauman, Ph.D.
Imagine a person
with a hearing loss so severe he can’t hear thunder rumbling overhead, yet, at
the same time, he has hearing so acute he can hear a pin drop; or imagine a
person that can’t hear you talking just 4 feet away, yet clearly hears a whisper
from across a large room; or imagine a person that can’t hear a car motor
running right beside him, yet can hear a single dry leaf skittering along in the
gutter 50 feet away.
“Impossible,” you say, “a person could never have such good
and bad hearing at the same time!”
Surprise! It’s true. Welcome to my world—the bizarre world
of people with extreme reverse-slope hearing losses.
What Is Reverse-Slope (or Low Frequency) Hearing Loss?
Hearing losses are sometimes classified according to the
shape they form on an audiogram. They commonly go by strange names such as
ski-slope loss, cookie-bite loss, flat loss, reverse cookie-bite loss and
reverse-slope (or reverse curve) hearing loss. (My article
Kinds of Hearing Losses
explains these different hearing losses and illustrates the various shapes they
form on audiograms.)
| Fig. 1. Severe ski-slope
By far the most common kind of hearing loss is the typical
ski-slope loss where the line on the audiogram slopes down to the right
(Fig. 1). In
contrast, a reverse-slope loss (as its name implies) does the reverse and slopes
up to the right (Fig. 2).
| Fig. 2. Severe reverse-slope
As a result, this kind of hearing loss is sometimes
referred to as an up-sloping loss, a rising loss, or low-frequency
hearing loss, but by far the most common name is the reverse-slope (or
reverse-curve) hearing loss.
| Fig. 3. Mild reverse-slope
Don’t make the mistake of thinking that all reverse-slope
losses are the same. Nothing could be further from the truth. There is an
enormous difference in hearing between a mild, gently-sloping reverse-slope
hearing loss (Fig. 3), and a severe or profound steeply-sloping reverse-slope
loss (Fig. 4), just as there is between the various degrees of ski-slope hearing
For practical purposes, we can group reverse-slope hearing
losses into three basic classes.
| Fig. 4. Neil's severe reverse-slope loss
at age 21
Class 1. The most common form of this
relatively-rare loss is a gently up-sloping line in the standard audiometric
frequencies between 250 and 8,000 Hz (Fig. 3). In this class, the worst
low-frequency hearing loss typically lies somewhere between mild and
moderately-severe. Class 1 curves are often seen in the beginning stages of
Class 2. Rarer, is a fairly-steep up-sloping
line in the standard audiometric frequencies. In this class, there is a moderate
to severe hearing loss in the frequencies below 1,000 Hz, but at the same time,
hearing becomes virtually normal somewhere in the range of 2,000 to 6,000 Hz
(Fig. 2). It is in Class 2 that the differences between reverse-slope losses and
ski-slope losses really become apparent.
Class 3. The rarest form of the reverse-slope
loss reveals a steep up-sloping line ranging from severe to profound hearing
loss (70 to 110 dB) in the low frequencies to incredible hearing in the very
high frequencies (those frequencies above 8,000 Hz) (Fig. 4).
Years ago (when I was in my early 20s) my hearing ranged
from 75 dB at 1,000 Hz to -30 dB in the frequencies above 16,000 Hz (Fig. 4).
(Note: numbers above the 0 dB line represent super-acute hearing, and are
expressed as negative numbers.) Since I could easily hear “silent” dog whistles,
some said I had “dog ears” hearing.
It is here in Class 3, with its incredible range of over
100 dB between the faintest low-frequency sound heard and the faintest
high-frequency sound heard, that truly bizarre hearing is the most pronounced.
Since my hearing loss spanned an incredible range of 105 dB, no wonder people
were always confused about what I could, and could not, hear!
For example, my former mother-in-law wouldn’t believe my
hearing was as bad as it was because she would whisper when she didn’t want me
to hear something, and I would easily hear her. (She never caught on that if she
just spoke in a normal voice, I wouldn’t have understood a thing!) (Back to Table of Contents)
How Common Are Reverse-Slope (or Low Frequency) Hearing Losses?
Mild reverse-slope hearing losses are relatively rare.
However, extreme reverse-slope hearing losses like mine are much rarer still.
Dr. Charles Berlin, formerly head of the Kresge Institute in Louisiana, one
researcher that has studied this kind of hearing loss fairly extensively,
estimates that out of the roughly 31 million hard of hearing people in the USA,
there are 3,000 plus people that have my unusual kind of reverse-slope hearing
loss. (Back to
Table of Contents)
Causes of Reverse-Slope (or Low Frequency) Hearing Losses
When people think of causes of reverse-slope losses,
typically they think about Meniere’s disease. Classic Meniere’s disease does
indeed often, but not always, result in a reverse-slope hearing loss (Class 1
curve), at least in the beginning stages.
However, probably the most common cause of reverse-slope
hearing losses, particularly in Classes 2 and 3, is of genetic origin.
Hereditary losses often seem to run in our families.
Reverse-slope hearing loss has run in my family for the
past four generations. Those that I know of include my maternal grandfather, my
mother, myself, my brother, my younger daughter and my brother’s older son. I
know of a number of other people who also have reverse-slope hearing losses
running in their families—some also for the past 4 or 5 generations.
It appears that extreme reverse-slope hearing losses are a
dominant genetic trait. It certainly is in my family. Each person born in
my family has a 50% chance of having this kind of hearing loss.
Another interesting characteristic of severe or extreme
reverse-slope hearing losses such as mine is that they seem to be
non-syndromic—that is, they don’t have any other conditions or syndromes
associated with them.
In addition to Meniere’s disease and genetic mutations,
various childhood diseases are thought to occasionally result in reverse-slope
hearing losses. As Judith explained, “My hearing loss apparently was the result
of measles at the age of 2.” Debbie’s daughter “was not born with a hearing
loss, but acquired it from complications of chicken pox” also at age 2. (Back to Table of Contents)
How Reverse-Slope (or Low Frequency) Hearing Losses Progress
Whether reverse-slope losses get worse with time depends on
what caused the loss in the first place. (Back to Table of
One of the characteristics of Meniere’s disease is that it
typically results in a progressive, fluctuating, step-wise hearing loss. Thus if
you have Meniere’s disease, initially you may have a Class 1 type of
reverse-slope loss. Over time, as your Meniere’s Disease progresses, you will
likely find that this reverse-slope loss slowly evolves into a reverse
cookie-bite or flat loss, and ultimately into some degree of a severe or
profound ski-slope loss. (Back
to Table of Contents)
With hereditary reverse-slope losses, we seem to go through
three distinct stages.
Stage 1: The first stage occurs from birth to around
5 years of age. It appears that although there is some degree of hearing loss at
birth, hearing in the lower frequencies rapidly decreases until around age 5 or
Furthermore, it seems that because of our excellent
high-frequency hearing, and because of our excellent speechreading skills at a
very early age (of which our parents are typically totally unaware), our hearing
losses do not become apparent until something happens to drive home the fact
that we cannot hear well.
For example, my parents didn’t discover I had a hearing
loss until I was about 4 or 5. One day my dad, who was standing behind me where
I couldn’t speechread him, asked, “Do you want to come for a ride in the car
with me?” I totally ignored him, and continued playing on the floor. He knew
something was wrong because I loved riding in the car! (It was a ‘29 Buick back
in those days.) Another time he asked me if I wanted some ice cream—which I
still love—and again I ignored him. It was at this point that my parents had my
hearing tested and discovered I had a severe hearing loss!
Stage 2: The second stage begins around age 5 and
continues without significant change to around age 50 (if there are no other
factors involved such as hearing loss from noise damage, or from taking ototoxic
drugs, for example). Thus, once we learn to adapt to our strange hearing losses,
our coping strategies can remain the same for most of our lives.
| Fig. 5. Average (ski-slope) hearing loss
curves with increasing
Stage 3: The third stage kicks in about age 50 and
continues for the rest of our lives. This is not really our reverse-slope
hearing loss progressing, but rather, the effects of aging dramatically
impinging on our precious high-frequency hearing. Here’s what happens.
As people age, they typically begin to lose their high-frequency hearing.
This happens slowly and insidiously over many years. Fig. 5 plots “average”
curves showing increasing high-frequency hearing loss from ages 40 (top line) to
age 80 (bottom line).
Notice that people with the typical ski-slope losses have
already lost their high-frequency hearing (but retain their low-frequency
hearing). Thus as they age, they don’t have much high-frequency hearing left to
| Fig. 6. Progression of Neil's reverse-
slope loss at age 59
In contrast, those of us with extreme reverse-slope losses
have most of our residual hearing in the high (and very high)
frequencies, yet it is these very frequencies that people typically lose as they
get older. As a result, somewhere around age 50 or so we begin to notice a
significant drop in our hearing. Our reverse-slope losses rapidly begin to
flatten, and in time become more or less “flat” curves.
For example, between ages 50 and 60, I lost much of my
excellent high-frequency hearing. You can verify this by comparing my audiogram
taken at around age 21 (Fig. 4) with my current audiogram (Fig. 6) taken at age
59. As you can see, I have lost much of my high-frequency
hearing. (In fact, I am following the same hearing loss pattern my mother went
though as she aged.) (Back to Table of
The Blessing of Perfect Speech
One of the things that surprises many people is that all of
us with severe reverse-slope losses have perfectly-normal or near-normal speech.
Imagine a person that is essentially deaf, yet has flawless enunciation,
perfectly-formed and well-modulated speech, all without having had any speech
therapy. This is one of the blessings of having a severe reverse-slope hearing
Shirley explains, “Because I have high-frequency hearing,
my voice has never been affected by my hearing loss, although my hearing loss is
It’s the same with me. Because my speech is also
indistinguishable from the speech of people with normal hearing, I’ve had many
people refuse to believe how bad my hearing really is. Peggy, herself hard of
hearing, after hearing me speak, exclaimed, “Do you realize that your speech is
absolutely perfect? You must have worked very hard to perfect your tone like
that, what with growing up hard of hearing.” The truth is, I’ve never had speech
therapy. I’ve never needed it.
The real secret to perfectly-normal speech is hearing
all speech frequencies, especially the high-frequency consonants such as
“s,” “f,” “sh,” “ch,” “t,” and “th.”
When you can’t hear these sounds, it is very difficult to
produce them properly. In fact, I can tell if a person has a profound loss just
by the way they move their lips when they try to produce these sounds. Think how
difficult, or impossible, it would be to learn to whistle if you couldn’t hear
any of the sounds you were trying to produce. In like manner, correctly
producing the above voiceless sounds depends so much on aural feedback—meaning
you listen to the sound you make, and if it isn’t “right on” you immediately
correct it. If you cannot hear it, you don’t get this feedback so you don’t
correct these sounds, and your poor speech reflects this.
Since those of us with severe reverse-slope losses hear
these “voiceless” sounds the best, we use them correctly in our speech, and thus
avoid the flat “deaf speech” patterns of many of those with severe ski-slope
losses. (Back to Table of
What It’s Like to Live with a Reverse-Slope (or Low
Frequency) Hearing Loss
Having a Class 2 or 3 reverse-slope loss makes for some
interesting experiences. Here are a few of the more bizarre things we hear, or
don’t hear, and how we cope with it.
- We don’t hear appliances running. Thus we have to put our hands on
household appliances (fridge, washer, drier, furnace, etc) and feel the
vibrations in order to know if they are running. However, we can readily hear
the faint click of the relays from across a room as they kick in or out to
start/stop these appliances, but we don’t know whether they just started or just
- We hear whispers very clearly—even from across a room. In school,
I used to hear kids whispering from across the classroom, yet couldn't hear the
teacher talking only a few feet away. It always puzzled me that the teachers
never heard all the whispering that to me was so loud. Since whispering seemed
so loud to me, when I used to “whisper,” I’d actually use “low voice” (which to
me sounded very faint as compared to whispering). To my chagrin, everyone around
heard me “whispering.” My wife kept telling me to “whisper.” It eventually
dawned on me that others couldn’t hear the whispers I so easily heard.
- Since I can’t hear my car’s motor running, sometimes when I am
parked I may try to start my car a second time thinking it hadn’t started. The
suddenly-swiveled heads of the people nearby tell me that I just ground the
gears on the starter—again! Now, I always look at the tachometer first. If it’s
not reading 0, I leave the starter alone!
- The screech of the wheels of trains on the tracks is so loud to me
that it hurts my ears—yet to most people this is not even a loud sound. Imagine
not being able to hear the loud roar of a train bearing down on you, yet getting
headaches from the painfully-loud screech (to me) of the train wheels against
the tracks as the train goes around a curve.
- We can easily hear high-frequency sounds most people can’t hear.
For example, I could easily hear the faint 15,734 Hz whine produced by the
fly-back transformer of a TV from anywhere in the house, and even from outside the house, yet I had to put my ear about 6 inches from the TV’s
speaker in order to understand any speech from it (if the volume was set to
normal hearing levels).
- To me, certain insects chirping from a block away (even just one
insect) produce a racket loud enough to drown out the voice of a person standing
almost nose-to-nose speaking. The “funny” thing (to me) is that people with
normal hearing either can’t hear that insect at all, or only hear it very
- We hear some birds singing and chirping away, but not others. For
example, I have never heard the low-frequency sounds of an owl hooting or a
Mourning Dove cooing (although I have a flock of Mourning Doves right outside my
back door), yet I can easily hear a male hummingbird’s high-pitched angry
squeaks as it chases off a competitor, or the wonderful trilling sounds it makes
as it power dives to impress its prospective mate.
- Although we have severe hearing losses in the speech frequencies,
we can easily hear faint high-frequency sounds such as a pin dropping on a table
or hard floor. Sarah explains, “I have a 60-80 dB reverse-slope hearing loss. I
can hear a pin drop, but normally can’t hear thunder!” (Back to Table of
Practical Differences Between Reverse-Slope and Ski-Slope Losses
Although there are many coping skills that are common to
all kinds of hearing losses, a number of the coping skills you typically read
about were designed with the needs of people with ski-slope losses in mind. They
were not designed for those of us with reverse-slope losses—yet people think we
need these coping strategies, but we often need the opposite. Here are three
1. People with ski-slope losses don’t want you to
speak louder, but clearer.
One of the “rules” when speaking to a hard of hearing
person (really meaning those with ski-slope losses) is that you don’t “yell” at
them, but speak slowly and clearly at your normal volume. This approach is
totally wrong for those of us with reverse-slope losses. We need people
to speak louder in order to hear speech in the first place.
If you have a ski-slope loss you hear the loud vowel
sounds, but not the soft consonants. Thus you hear people talking with no
problem, but because most of the intelligence of speech is in the consonants,
you don’t understand what people are saying. To you, speech sounds muffled
because you don’t hear the high-frequency sounds. Thus you primarily want more
clarity, not more volume.
In contrast, those of us with reverse-slope losses hear the
soft, high-frequency consonant sounds. To us, speech is thin, almost inaudible
and often sounds like whispers. For example, as I approach someone talking, the
first sounds I hear are the high-frequency voiceless “s” sounds. We do not
really hear a person talking until we get very close so we can hear the “voiced
sounds.” Thus we typically need more volume.
2. People with ski-slope losses hear men better than
“Common wisdom” says that hard of hearing people hear men
better than women and children. This is true for people with the typical
ski-slope losses because they hear the louder, lower-pitched voices of men
better. Women and children with their higher-pitched (and often softer) voices
are much more difficult for them to hear and understand.
This “wisdom” is again totally wrong for those of us with
reverse-slope losses. Since we hear the higher-frequency sounds best, we
typically hear women’s voices better than men’s voices. I much prefer talking to
women as their higher-pitched voices are more in tune with my ears. If men speak
in a high falsetto voice I then hear them well too. It might sound ridiculous,
but it works!
3. If you have a ski-slope loss, low-frequency noise
drowns out speech.
Loud low-frequency noise is the bane of people with
ski-slope losses. Speech is lost in the racket caused by the noise in factories
and mills, and by the air conditioning/heating fans in our homes, offices and
schools, thus people with ski-slope losses have to shout over all the
low-frequency noise around them. Since we don’t hear low-frequency sounds well,
we clearly hear the people shouting. That’s one situation where I tell people
(tongue in cheek), “You don’t have to yell at me. I’m not deaf!” By the same
token, we often do not raise our voices enough in such situations so people with
normal hearing can hear us talking over the low-frequency racket.
In contrast, we cannot hear speech through all the
high-frequency sounds around us. The bane of our lives are nearby sounds such as
running water, clinking cutlery, rustling and crumpling papers and people
whispering. (Back to Table of
This has been just a brief introduction into the bizarre
world of extreme reverse-slope hearing losses. If you want to learn more about
reverse-slope hearing losses, including issues such as diagnosing (and
misdiagnosing) reverse-slope losses, testing and fitting hearing aids, cochlear
implants and assistive devices to people with reverse-slope losses, and a number
of other topics, click here to read the unabridged article.
If you (or a family member) have a reverse-slope loss
and would like to join an information and support email list for people (and
parents of children) with reverse-slope hearing losses, type your E-mail address in the box and click on the Yahoo Groups button. You can unsubscribe at any time.)
Subscribe to the Reverse Slope
Hearing Loss (RSHL) list
(Back to Table of Contents)
The above article was published in the Summer 2007
edition of Hearing Health magazine.