Hyperacusis

Hyperacusis (or hyperacousis) is a 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, some of which may seem unpleasantly or painfully loud to that person but not to others.

Hyperacusis is often coincident with tinnitus. Both conditions have a prevalence of about 10–15% and hearing loss as a major risk factor. However, there also appear to be important differences between the mechanisms involved in tinnitus and hyperacusis.

 

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 come down with 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.

 

Associated conditions

Some conditions that are associated with hyperacusisinclude:

• Acoustic shock
• Adverse drug reaction
• Anxiety
• Autism spectrum
• Lyme disease
• Migraine
• Ménière’s disease
• Endolymphatic hydrops
• Multiple Sclerosis
• Noise-induced hearing loss
• Posttraumatic stress disorder
• Severe head trauma
• Superior canal dehiscence syndrome (SCDS)
• Systemic lupus erythematosus (SLE)
• Tay–Sachs disease
• Williams syndrome

 

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 caused – mainly – by hearing loss related damages in the inner ear.

 

Diagnosis

 

MATLAB Handle Graphics

Loudness discomfort levels (LDLs): group data of hyperacusis patients without hearing loss. Upper line: average hearing thresholds. Lower long line: LDLs of this group. Lower short line: LDLs of a reference group with normal hearing.

 

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) 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.

Another possible treatment is cognitive behavioral therapy (CBT), which may also be combined with retraining therapy.

 

Notable cases

• Musician Jason DiEmilio of Azusa Plane suffered from hyperacusis. His story was told in BuzzFeed.
• Musician Stephin Merritt suffers from 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.
• Musician Laura Ballance of Superchunk suffers from hyperacusis and no longer tours with the band.
• American politician, LGBT activist, and film producer Michael Huffington has mild hyperacusis and underwent sound therapy after finding that running tap water caused ear pain.
• Russian communist revolutionary, politician, and political theorist Vladimir Lenin was reported seriously ill by the latter half of 1921, suffering from regular headache, insomnia and hyperacusis.