Hyperacusis is a rare debilitating hearing disorder characterized by an increased sensitivity to certain frequencies and volume ranges of sound. A person with severe hyperacusis has difficulty tolerating everyday sounds, which become painful or loud. The prevalence of hyperacusis is 1 in 50,000 people. Hyperacusis is often coincident with tinnitus. However, tinnitus is more common and there are important differences between their involved mechanisms.
Signs and symptoms
In hyperacusis, the symptoms are ear pain, annoyance, and general intolerance to many sounds that most people are unaffected by. Crying spells or panic attacks may result from the experience of hyperacusis. It may affect either or both ears. Hyperacusis can also be accompanied by tinnitus. Hyperacusis can result in anxiety, stress and phonophobia. Avoidant behaviour is often a response to prevent the effects of hyperacusis and this can include avoiding social situations.
Associated conditions
Some conditions that are associated with hyperacusis include:
The most common cause of hyperacusis is overexposure to excessively high decibel levels. Some sufferers acquire hyperacusis suddenly as a result of taking ear sensitizing drugs, Lyme disease, Ménière's disease, head injury, or surgery. Others are born with sound sensitivity, develop superior canal dehiscence syndrome, have had a history of ear infections, or come from a family that has had hearing problems. Some psychoactive drugs such as LSD, methaqualone, or phencyclidine can cause hyperacusis. An antibiotic, ciprofloxacin, has also been seen to be a cause, known as ciprofloxacin-related hyperacusis.
Neurophysiological mechanisms
As one important mechanism, adaptation processes in the auditory brain that influence the dynamic range of neural responses are assumed to be distorted by irregular input from the inner ear. This is mainly caused by hearing loss related damage in the inner ear.
Diagnosis
The basic diagnostic test is similar to a normal audiogram. The difference is that additionally to the hearing threshold at each test frequency also the lowest uncomfortable sound level is measured. This level is called loudness discomfort level, uncomfortable listening level, or uncomfortable loudness level. In patients with hyperacusis this level is considerably lower than in normal subjects, and usually across most parts of the auditory spectrum.
Treatment
One possible treatment for hyperacusis is retraining therapy which uses broadband noise. Tinnitus retraining therapy, a treatment originally used to treat tinnitus, uses broadband noise to treat hyperacusis. Pink noise can also be used to treat hyperacusis. By listening to broadband noise at soft levels for a disciplined period of time each day, patients can rebuild their tolerances to sound. Although patients might not always make a complete recovery, the use of broadband noise usually gives some of them a significant improvement in their symptoms, especially if this is combined with counseling. Another possible treatment is cognitive behavioral therapy, which may also be combined with retraining therapy.
Musician Stephin Merritt has monaural hyperacusis in his left ear, which influences the instrumentation of his band, The Magnetic Fields, leads him to wear earplugs during performances and to cover his affected ear during audience applause.
Russian communist revolutionary, politician, and political theoristVladimir Lenin was reported seriously ill by the latter half of 1921, having hyperacusis and symptoms such as regular headache and insomnia.
Musician Chris Singleton had hyperacusis, but made a full recovery. His story was told in The Independent.
Musician Peter Silberman of The Antlers had hyperacusis and tinnitus which put his musical career on hold, but was quoted saying it died down to a 'manageable level' He has now resumed his musical career.
Voice actorLiam O'Brien has hyperacusis, and is quoted as having lost sleep during the time of diagnosis.
