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Sensitivity to Loud Sounds

Abnormal Loudness Sensitivity: Hyperacusis and Recruitment

Hypersensitivity to loud sounds—or in some cases, soft sounds or even all sounds—can be a real problem for some people. There are two different types of loudness-sensitivity, with different causes and different treatment approaches. Hyperacusis is the term used to describe this phenomenon in persons with normal or near-normal hearing. The term recruitment describes abnormal loudness sensitivity in hearing-impaired individuals.

What is Hyperacusis?

Hyperacusis is an abnormal sensitivity to loud sounds in people who have essentially normal hearing, who experience everyday noises as uncomfortably or painfully loud. Hyperacusis-sufferers can sometimes begin to rely heavily on earplugs and earmuffs to deal with the discomfort of not just very loud sounds such as the sound of a lawn mower or power tools, but the everyday sounds of life. Hyperacusis is very often present with tinnitus, but is sometimes present without tinnitus.

What Causes Hyperacusis?

There are various suspected causes, and this is an area that is still being researched. Possible suspected causes can include noise exposure (which can cause subtle damage, even without significant hearing loss present), closed head injuries and possibly brain chemistry dysfunction (certain chemicals not being utilized properly by the brain).

What Can Be Done to Help Hyperacusis Sufferers?

First, it is important to see your audiologist and otolaryngologist or otologist to have a thorough audiologic and medical evaluation. At ACENTA, we can provide these evaluations.

Following evaluation, we recommend consultation with one of our ACENTA audiologists who can assist with the following treatment approaches, and customize a treatment plan for your individual needs.

Research and clinical experience have shown that hyperacusis sufferers are not served well by wearing earplugs or earmuffs and shielding themselves from everyday sounds. Excessive use of noise protection has been shown to make the condition worse.

It is perfectly appropriate to use hearing protection for loud, potentially damaging sounds, i.e. sounds that are 85 decibels (dB SPL) and above, such as power tools, lawn mowers, industrial machinery, most concerts and bands at receptions, clubs or parties. Sometimes vacuum cleaners and blow dryers may also produce sounds in or near this range. It is very important to protect your ears from such sounds, especially if you suffer from tinnitus and/or hyperacusis. Patients with hyperacusis who rely too heavily on earplugs to cope with everyday sounds are encouraged to gradually reduce the use of earplugs until they are able to wear them only for protection from potentially damaging sounds.

Hyperacusis can usually be treated with considerable success. There is no “cure” but improvement can generally occur with the use of a special, proven approach called Habituation Therapy. This is combined with the strategy discussed above of gradually reducing and eliminating any excessive reliance on earplugs.

An important aspect of Habituation Therapy involves presenting masking sounds to each affected ear at extremely soft levels that are not bothersome to the patient. This involves fitting ear-level masking devices that look like a hearing aid but do not amplify sound; they provide a very soft sound similar to white noise. These devices need to be worn consistently (a minimum of eight hours per day) for most of each day, everyday. Listening to the soft sound (which can sometimes be adjusted to near or even just below the softest level the person can hear to be barely perceptible or imperceptible) retrains the brain to enable the person to have more normal loudness perception and loudness tolerance.

Over time, with adjustments to the treatment protocol by the audiologist, hyperacusis can improve markedly. The patient is also advised to avoid silence and maintain a constant level of background noise—however soft it may be—in the environment. Environmental maskers such as fans, air conditioners, radios tuned between stations, air purifiers, and even special “masking CDs” can help the patient maintain constant sound that will help retrain their brain to be able to handle sound in a more normal fashion over time. This approach has been proven successful for most hyperacusis sufferers in reducing their degree of difficulty with loudness tolerance.

What is Loudness Recruitment and How Does It Differ From Hyperacusis?

Loudness Recruitment refers to the abnormal perception of loudness that sometimes can occur with a sensorineural hearing loss. Typically, a person with recruitment will hear a relatively soft sound (loud enough for them to hear, of course), as “soft” but as the loudness level increases, then suddenly, just a few decibels above a level where the sound was comfortable, the sound is perceived as uncomfortably loud.

This abnormal growth in loudness perception is a fairly common accompaniment to sensorineural hearing loss and is caused by the same inner ear sensory cell dysfunction (damaged or missing hair cells) that caused the hearing loss. It can be present in varying degrees in people with sensorineural loss. It does not always present a problem but in some cases it can be just as bothersome as hyperacusis.

Sometimes it can cause the range of useable hearing to be very narrow and can complicate hearing aid fitting. Recruitment differs from hyperacusis in two ways: first, hearing loss is present with recruitment but not with hyperacusis, and second, generally only loud sounds are uncomfortable for persons with recruitment; persons with hyperacusis tend to experience soft or moderately-loud sounds as painfully loud, as well as truly loud sounds.

How Can Persons Bothered by Recruitment Be Helped?

It is difficult to generalize about the approach to helping patients with recruitment, because each patient’s individual pattern of hearing loss and recruitment characteristics is different, and therefore the needs are different. Recruitment sufferers whose hearing loss is appropriate for amplification can often be fit successfully with a hearing aid when special attention is paid to selecting appropriate features for loudness control.

Recruitment can sometimes cause a person’s range of useful hearing to be smaller than normal, but this can often be successfully accommodated through appropriate hearing aid selection. Some of the features made possible by digital technology make digital hearing aids the optimal choice for some recruitment sufferers. Your ACENTA audiologist can advise you on the best choices for your particular needs.