Hyperacusis--Causes and Treatments
William Kaufman
Glenda Demaree
NOTE: for more updated information, please also check out
www.hyperacusis.net.
Hyperacusis is used to describe a high level of sensitivity to sound.
It is also known as dysacusis, oxylacusis, hypersensitive hearing, or
phonophobia. Persons with hyperacusis do not show abnormal loudness
growth but an abnormal discomfort for suprathreshold sound (Barnes &
Marriage, 1995). Audiograms for hyperacusis sufferers are typically
normal. They show normal sound thresholds but the sensitivity level is
above normal. The comfort level for most people is below 100 decibels.
People with hyperacusis can experience discomfort at 40 to 50 decibels
or lower (Schwade, 1995). The disorder may be frequency-specific
(Schwade, 1995). Not all sounds of the same loudness (number of
decibels) cause discomfort, but only sounds within a certain range,
thus a small change of frequency may cause discomfort at low volume.
The prevalence rate of hyperacusis is unknown. It frequently occurs
with tinnitus, which afflicts approximately 40 million poeple in the
United States (Hazell & Jastreboff, 1933). A questionnaire in a clinic
population by Sanchez and Stephens (1997) found that eight percent of
tinnitus sufferers have hyperacusis. These two studies would suggest
about 3 million people in the United States have hyperacusis. Further
a survey conducted by the Autism Research Institute found up to 40% of
children with autism to be affected by hyperacusis. Hyperacusis also
has an occurence rate of 95% in children with Williams syndrome
(Borse, Curfs, & Fryns, 1997). These facts plus its comorbidity with
many other diseases leads one to believe hyperacusis is not an
extremely rare disease.
Hyperacusis is a poorly understood disorder resulting in many theories
of etiology and prognosis. Hyperacusis can occur alone or in
conjunction with other disorders. A sudden single burst of noise
(Schwade, 1995), a head injury (American Speech-Language Hearing
Association, 1995), or surgery to the face or jaw (Barnes & Marriage,
1995) can result in hyperacusis. Barnes and Marriage also proposed two
types of hyperacusis, peripheral and central.
Peripheral hyperacusis is when the earÕs built in mechanism against
loud or sharp sound seems to have been turned off. Absence of acoustic
reflexes, positive history of vestibular disorders, MeniereÕs disease,
or perilymph fistula account for peripheral hyperacusis. Hyperacusis
co-occurring with BellÕs palsy, Ramsey Hunt syndrome, and myasthenia
gravis is also considered to be peripheral hyperacusis. Hyperacusis is
also an otological complication of herpes zoster (Adour, 1994) and
craniomandibular disorders (Erlander and Rubinstein, 1991).
Barnes and Marriage (1995) proposed another type of hyperacusis called
central hyperacusis. Central hyperacusis results in an inability to
tolerate specific but not necessarily loud sounds. Certain sound waves
reaching the inner ear are somehow overamplified or magnified on the
way to the brain or by the brain. A global sensitivity may exist to
explain central hyperacusis. Barnes and Marriage (1995) list the
following clinical conditions as co-occurring with central
hyperacusis: migraine, depression, pyridoxine deficiency,
benzodiazpine dependence, musicogenic epilepsy, Tay-SachÕs disease,
post-traumatic stress disorder, and chronic/postviral fatigue
syndrome. Some manic individuals also report having a much sharper
sense of hearing (American Psychiatric Assciation, 1994). Children who
have autism or pervasive developmental disorder may also have
hyperacusis (American Speech-Language Hearing Association, 1995).
Many treatments have been tried for hyperacusis; one which has
received mixed support is the use of earplugs. Dr. Jack Vernon,
director of the Oregon Hearing Research Center, and Dr. Pawell
Jastreboff, director of the Tinnitus and Hyperacusis Center of the
School of Medicine, University of Maryland, advise against using
earplugs (Schwade, 1995). Earplugs deprive the auditory system of
sound. The ears try to compensate by amplifying the weak sounds and
become even more sensitive over time. For behavior management in
children who have autism Borsel, Curfs, and Fryns (1997) advised
parents to use earplugs, to purchase household appliances with a low
noise level, and to explain the origin of the sound to the child.
Using sound-absorbing draperies, carpets, and furniture, or cushioning
appliances can also make everyday noises less bothersome (American
Speech-Language Hearing Association, 1995).
A more consistently supported treatment for hyperacusis is sound
desensitization. This treatment is used at both the Oregon Hearing
Research Center (Schwade, 1995) and the Tinnitus and Hyperacusis
Center (Hazell and Jastreboff, 1993). Treatment involves listening to
noise just below the intolerance level for several hours a day. Over
time a tolerance to sound is built up, resulting in normal
environmental sounds no longer causing discomfort or pain. Individual
patients respond at diffeent rates to the treatment. Some conditioning
occurs rapidly, but treatment can last l to l.5 years or more.Both
centers individualize The Tinnitus and Hyperacusis Center includes an
otolaryngologist, audiologist, and neurophysiologist (Hazell and
Jastreboff, 1993). Prior to using the noise for treatment the ear and
auditory system are explained to the patient. The patientÕs thinking
about hyperacusis is also examined and possibly retrained. The
acoustic element of the plan is them implemented. Low level, stable,
white noise is produced by a wearable noise generator. White noise is
a full spectrum of frequencies that together sound like the static
between stations on an FM radio.
Dr. Vernon at the Oregon Hearing Research Center individualizes sound
desensitization treatment for hyperacusis. Rather than using white
noise, tolerance is developed through the use of low frequency sounds
called pink noise. This noise is similar to the sound of ocean waves
breaking.
While medication is not used as treatment for hyperacusis, it is often
used to help patients cope with stress caused by the disorder. The
Tinnitus and Hyperacusis Center uses antidepressants and antianxiety
drugs to help patients cope until the hyperacusis can be
improved(Schwade, 1995). However, a study by Szcepaniak and Moller
(1995) found L-sbaclofen, a muscle relaxant, to be effective in
suppressing excitation in the ascending auditory system. Further study
is needed before it is used as a treatment for hyperacusis. Another
treatment used for hyperacusis is Auditory Integration Training (AIT).
AIT lacks experimental evidence and is controversial (American
Speech-Language Hearing Association, 1995). The treatment involves
listening to modulated music with specific frequencies electively
filtered. Three machines (Audiokinetron, BGC Audio Tone
Enhancer/Trainer, AudioScion) are available for AIT treatments
(Barkell & Malgeri, l99). Safety concerns about the equipment have
resulted in the U. S. Federal Food and Drug Administration directing
that additional research on the AIT devices be conducted prior to
continued distribution. The safety concerns are about the
specifications of the machines and their effects on the userÕs hearing
ability. The American Speech-Language Hearing Association supports the
need for this research (American Speech-Language Hearing Association,
1995). Another problem with AIT is no training standards and
guidelines for AIT trainers.
Other treatments for hyperacusis include biofeedback and relaxation
techniques (American Speech-Language Hearing Association, 1995). Meyer
Rosen, a hyperacusis sufferer, has tried food desensitization,
exposure of nasal passages to essential oils, neurolinguistic
training, rehydration of mucous membanes, correction of head-forward
posture, scalp and body acupuncture, progressive relaxation of the
temporomandibular joint musculature by an orthopedic mandibular
repositioning device, and the use of an earplug prescription. After
much study Meyer developed an acupuncture treatment called
Reflex-Correspondence Training (Rosen, 1995). All of these treatments
lack scientific evidence.
All aspects of hyperacusis need future research. There appear to be
many causes for hyperacusis. The physiological and psychological
factors need to be determined as causing or contributing to the
disorder. New treatments need to be discovered, and the present
treatments need to be placed on a scientific basis. At the present
time hyperacusis sufferers are receiving treatments with the hope that
help will be obtained, and permanent damage will not result to their
auditory systems.
For a referral to an American Speech-Language Hearing Association
(ASHA) certified audiologist in your area, call ASHSÕs Information
Resource Center at (800) 638-8225. Additional information can be
obtained by contacting The Hyperacusis Network, write or call The
Hyperacusis Network, 444 Edgewood Drive, Green Bay, WI 54302 (414)
468-4667.
REFERENCES
Adour, K. K. (1994). Otological complications of herpes zoster. Annals
of Neurology, 35, S62-S64.
American Psychiatric Association (1994). Diagnostic and Statistical
Manual of Mental Disorders (4th ed.). Washington, DC: Author.
American Speech-Language Hearing Association (1995). Hyperacusis.
ASHA, 37, 53-54.
Barnes, N. M. & Marriage, J. (1995). Is central hyperacusis a symptom
of 5-hydroxytryptamne (5-HT) dsyfunction?. The Journal of Laryngology
and Otology, 109, 915-921.
Berkell, D. E., Malgeri, S. S., & Streit, M. K. (1996). Auditory
integration training for individuals with autism. Education and
Training in Mental Retardation and Developmental Disabilities, 31(1),
66-70.
Borsel, J. V., Curfs, L. M., & Fryns, J. P. (1997). Hyperacusis in
Williams syndrome: A sample survey study. Genetic Counseling, 8(2),
121-126.
Erlander, S. I. & Rubinstein, B. (1991). A stomatognathic analysis of
patients with disabling tinnitus and craniomandibular disorders (CMD).
British Journal of Audiology, 25, 77-83.
Hazell, J. W. & Jastreboff, P. J. (1993). A neurophysiological
approach to tinnitus: Clinical implications. British Journal of
Audiology, 27, 7-17.
Moller, A. R. & Szczepaniak, W. S. (1995). Effects of L-baclofen and
D-baclofen on the auditory system: A study of click-evoked potentials
from the inferios colliculus in the rat. Annal of Otology Rhinology &
Laryngology, 104, 399-404.
Rosen, M. R. (1995). New treatment possibilties for hyperacusis--a
painful, ultrasensitivity to normal sounds (letter to the editor).
American Journal of Acupuncture, 23(1), 74-76.
Sanchez, L. & Stephens, D. (1997). A tinnitus problem questionnaire in
a clinic population. Ear & Hearing, 18, 210-217.
Schwade, S. (1995). Shedding light on supersensitive hearing: What to
do when every small noise sounds like the big bang. Prevention, 47(8),
90-96.
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