Hyperacusis refers to an unnaturally intense sensitivity to sound. A person with this condition has lost most of his/her dynamic range (the ear's ability to accommodate quick shifts in the loudness of sounds).
It's a matter of degrees. Everyday noise has become incidental in the 21st century, and most of us take these sounds for granted. When people hear traffic sounds, for example, they tend to "tune out" and continue with whatever they're doing - but if they hear a loud siren start up very close to them, they may cover their ears in an attempt to lessen the discomfort of the invasive sound. To a person with hyperacusis, the traffic noises alone may produce enough distress to evoke the response of covering the ears.
With respect to those who have hyperacusis, this does not diminish the distress that results from the condition, which can prove devastating for relationships and careers. But it is important that people with hyperacusis realize their auditory systems are most likely not damaged in any way, and that there is help for them.
Did you know that Tinnitus Retraining Therapy (TRT) has been known to cure hyperacusis? Ironically, it cannot "cure" tinnitus, because with that condition there is no particular generator of the sound in question. Hyperacusis is more subject to being affected by the treatment. A form of desensitization, TRT represents a landmark breakthrough in the treatment of hyperacusis.
The onset of hyperacusis can be sudden or gradual. For some, its beginnings develop slowly, with no specific event triggering the phenomenon. For others, it begins with an extremely loud noise or event - the firing of a gun or a rock concert.
In addition, hyperacusis can occur as the result of particular medications, Meniere's, head injury, job-related noise exposure, TMJ and even some surgeries. Hyperacusis typically occurs in the absence of any hearing loss.