Hyperacusis is a very rare debilitating hearing disorder characterized by an increased sensitivity to certain frequencies and volume ranges of sound (a collapsed tolerance to usual environmental sound). A person with severe hyperacusis has difficulty tolerating everyday sounds, which become painful or loud.

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.

CAUSES

The most common cause of hyperacusis is overexposure to excessively high decibel (sound pressure) 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 (angel-dust) can cause hyperacusis. An antibiotic, ciprofloxacin, has also been seen to be a cause, known as ciprofloxacin-related hyperacusis. 

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 (LDL), uncomfortable listening level (UCL), or uncomfortable loudness level (ULL). 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 (i.e., re-establish) their tolerances to sound.