| Hyperacusis:
When Hearing Hurts
by Barry Keate
 Hyperacusis
is a condition of extreme sensitivity to sounds. People
who suffer from hyperacusis experience ordinary sounds
as being unbearably loud. Those who develop severe
cases often go to great lengths to diminish the impact
of environmental sounds, including moving to new homes,
purchasing quieter vehicles or isolating themselves
socially.
Known
causes of hyperacusis include sensorineural hearing
loss, head trauma and TMJ (temporomandibular joint)
disorder, acoustic trauma, autism, epilepsy and schizophrenia,
among others. It can also be triggered by some prescription
medications such as antidepressants, antipsychotics,
anesthetics and illicit drugs. About 70% of hyperacusis
patients report some form of hearing loss.
It
is generally agreed that 25 to 40% of hyperacusis
patients experience chronic tinnitus. However, there
is a dramatic difference of opinion in the percentage
of tinnitus patents who experience hyperacusis. Pawell
Jastreboff, Ph.d., Sc.D., and Jonathan Hazell, FRCS.,
who together developed Tinnitus Retraining Therapy
(TRT), report that about half of their tinnitus patients
also experience hyperacusis.
 On
the other hand, Jack Vernon, Ph.D., Professor Emeritus
of Otolaryngology at the Oregon Health Sciences University
says that in his experience less than 1% of tinnitus
patients also report hyperacusis. Whatever the percentages
may be, it is estimated that 3-4 million people in
the USA suffer from it.
In a survey conducted by the American Tinnitus Association,
of 112 patients with both tinnitus and hyperacusis,
53% reported their hyperacusis was worse than the
tinnitus, 25% reported both problems as equally disturbing
and only 16% who said the tinnitus was the most bothersome
problem. For this reason, in patients with both tinnitus
and hyperacusis, the hyperacusis is usually treated
first.
The
exact genesis of hyperacusis is unknown but there
are studies that point to the part of the auditory
system that regulates instructions from the central
nervous system. In the normal ear, very soft sounds
are amplified and very loud sounds are inhibited by
actions of the middle ear muscles and bones. In the
case of hyperacusis, the central nervous system does
not respond properly to the incoming signal. This
creates the situation where an ordinary level of sound,
such as conversational noise, is perceived as if it
were as loud as a jet engine.
Dr.
Vernon defines hyperacusis as the collapse of loudness
tolerance so that almost all sounds produce loudness
discomfort even though the actual sound intensity
is well below that judged to be uncomfortable by others.
He also states that the higher the pitch of the sound
the less the loudness tolerance. Typically the threshold
of discomfort for hyperacusis patients is about 20
to 25 dB above the hearing threshold for low pitched
sounds of 200 Hz or so and progressively declines
until it is only 3 to 5dB or less above threshold
for sounds at 10,000 Hz and above.
There
are two medically accepted treatments for hyperacusis
and there is quite a bit of convergence between the
two. Both Tinnitus Retraining Therapy and pink noise
therapy are available and practitioners of both therapies
agree on several basic principles.
Most
people who suffer from hyperacusis attempt to protect
their ears by avoiding sounds and using ear plugs
and/or ear muffs. In the above mentioned survey by
the ATA, 93% of hyperacusis patients reported wearing
ear plugs. This type of protection is false security
and one way to almost surely make hyperacusis worse.
The practice leads people to develop phonophobia,
which is an overwhelming fear of sound or noise. A
vicious cycle of overprotection, hyperacusis and phonophobia
develops which leads people to withdraw from family,
friends and work. It has disastrous consequences on
the person’s personal relationships, self-image,
lifestyle and quality of life.
Tinnitus
Retraining Therapy (TRT) was developed during the
1980’s by Drs. Jastreboff and Hazell. The aim
of the therapy is to retrain the patient’s brain
so they learn how to treat tinnitus and hyperacusis
the way they treat the sound of the refrigerator in
their kitchen; a sound which they normally are not
aware of but when they do hear it, it is not bothersome.
There
are two components of TRT: directive counseling and
sound therapy usually with the use of sound generators.
Directive counseling teaches the patient to understand
the mechanisms of hearing and basis of the brain function.
Sound therapy is used to stimulate the cochlea in
a controlled way which leads to improved thresholds
for sound tolerance over time. Improvement in hearing
thresholds begins after about three months with further
improvement noted in six months to a year.
We
published an in-depth look at TRT in a previous article
that can be seen by clicking
here.
Dr.
Vernon has also developed a treatment for hyperacusis.
He also believes that overprotection of the ears will
cause a worsening of hyperacusis. His staff has been
developing a special hearing aid called the *2000
that employs extensive compression so that sounds
of any sort cannot rise above approximately 65 dB
and very low intensity sounds are amplified up to
a comfortable level that is adjustable. In this way,
hyperacusis patients can feel more confident in going
about their daily activities.
The
second part of the desensitizing procedure is to listen
to “pink noise” through earphones for
about two hours each day. Pink noise is a variant
of white noise. Pink noise is white noise that has
been filtered to reduce the volume at each octave.
This is done to compensate for the increase in the
number of frequencies per octave. Each octave is reduced
by 6 decibels, resulting in a noise sound wave that
has equal energy at every octave. The listening level
is determined by the patient so that it is at the
loudest level that is comfortable. As hearing threshold
comfort levels increase over time, the sound is turned
up.
Dr.
Vernon states that desensitizing the hyperacusis patient
is a very slow process and can take up to two years.
The length of treatment depends on how long the hyperacusis
has been present. Recent onset can usually be desensitized
fairly quickly, however most people have slowly developing
hyperacusis and usually wait for some time before
seeking help. He recommends that hyperacusis patients
join Dan Molcore’s Hyperacusis Network, 444
Edgewood Drive, Green Bay, WI 54302, phone 414 468-4663.
Since
a significant majority of hyperacusis patients also
have hearing loss and many have tinnitus, Arches Tinnitus
Relief Formula® (TRF) may be beneficial in its
treatment. Typically, reduction of tinnitus symptoms
also helps to reduce sensitivity to hyperacusis. Numerous
clinical studies have shown that two of the ingredients
used in Arches TRF, Ginkgo biloba extract and chelated
zinc, are beneficial in improving hearing loss and
reducing tinnitus.
There
have not been clinical studies conducted specifically
on the ingredients in Arches TRF and hyperacusis.
However, anecdotal reports indicate that as the hearing
improves and tinnitus is reduced, hyperacusis becomes
desensitized as well. |