Most of us are aware of hearing loss and the difficulty associated with not being able to hear conversation or other important sounds. What about the people who suffer (suffer is the correct word to use here) with hyperacusis? One in 50,000 people reportedly suffer from hyperacusis.
What is Hyperacusis?
The definition of hyperacusis varies and may even seem unclear. Most audiologists define hyperacusis as a condition in which a person has intolerance to a level of sound. It can be defined as a condition that is a disorder of the perception of loudness of sound. This may also occur with what you might consider a soft sound.
The physical characteristic of the sound need not be loud to have the sensation of pain or discomfort. Another way to describe hyperacusis is a decrease in sound tolerance. There are other definitions for sound intolerance, such as phonophobia: the fear of a sound; and misophonia: a negative reaction to a sound. The term hyperacusis is usually reserved for individuals who feel that particular pitches or sounds cause physical discomfort. Individuals may describe discomfort, pain, tingling or pinging.
What Causes Hyperacusis?
A hypothesis about the cause of hyperacusis is that the individual has a reduced nerve input in response to sound. This causes the brain to attempt to compensate and increase the gain of the sound, which causes the over-amplification. This means that the issue is in two areas: the hearing organ and the auditory path in the brain.
There are people who have increased activity of a muscle that tenses the eardrum called the tensor tympani. This muscle is designed to contract in response to loud sound but in some individuals the muscle moves too much and causes discomfort. Hyperacusis is more prevalent in people with a history of noise exposure, ringing in the ears, physical trauma to the head or viral infection of the inner ear. There are conditions associated with hyperacusis, including Bell’s palsy, Lyme disease, depression and autism. Actual hearing ability does not seem to predispose someone to this condition. People with hearing loss or normal hearing may experience the discomfort.
How is Hyperacusis Tested?
All forms of hearing sensitivity are tested by having a person sit in a very quiet room and listen through earphones for pure tones or speech signals. The unique nature of hyperacusis shows as a reduction in loudness growth from the pure tones or standardized environmental sounds. The individual will say that sound which is slightly louder than what they can just hear is uncomfortable. A normal response to stepping the sound up louder and louder while staying comfortable is about 100dB! A person with hyperacusis may only tolerate an increase of 10dB.
The two most common management techniques for hyperacusis are counseling and sound therapy. Counseling for hyperacusis includes activities that are focused on cognitive behavior therapy, helping the individual to adjust his or her perceptions of sound. The individual is exposed to the noise in a controlled environment and the noise is increased in volume and the length of time of the session is increased. Some of these therapies focus the sound to be similar to the difficult sounds; other therapies focus on general environmental sounds. The therapy is a slow process but people with significant hyperacusis are thankful that they can try this technique rather than withdraw from the sounds of society.
Wearing Musicians’ Earplugs
Another treatment is noise reduction by wearing musicians’ earplugs. These are custom-fit earplugs that are comfortable enough to wear day and night. This type of noise reduction does not completely block your hearing but reduces the extreme edges of sound. The plugs come in 9dB, 15dB and 25dB sound-reduction options.
The plugs have a diaphragm that functions as an acoustic filter to give various amounts of reduction to sound. The 9dB reduces the sounds through the middle frequencies, the 15dB uniformly reduces sound across all frequencies and the 25dB gives a relatively flat sound reduction across all frequencies. The sound of your own voice sounds the most natural using these filters (not muffled). The goal is to wear the least amount of noise reduction so that your natural auditory filter is given the chance to work as much as possible. Many people find that they only need to wear the plugs in certain situations and they are comfortable enough not to wear them in other situations.
It is important to discuss your hearing issues with an audiologist. A professional will be able to point you in the right direction. QCBN
By Karon Lynn, Au.D.
Trinity Hearing Center is located at 1330 N. Rim Dr., Suite B in Flagstaff. For more information, visit the website at TrinityHearing.net. Karon Lynn is a doctor of audiology with 30 years of experience working with hearing impaired individuals. Dr. Lynn may be reached at 928-522-0500 or at firstname.lastname@example.org.