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 Formula® (ATF) 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 ATF, Ginkgo biloba extract with Ginkgo Max 26/7 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.