Hyperacusis is the increased sensitivity to sound and a low tolerance for environmental noise. Definitions of hyperacusis can vary significantly; it can refer to normal noises being perceived as: loud, annoying, painful, fear-inducing, or a combination of those, and is often categorized into four subtypes: loudness, pain, annoyance, and fear.
It can be a highly debilitating hearing disorder. Hyperacusis is often coincident with tinnitus. The latter is more common and there are important differences between their involved mechanisms.
Little is known about the prevalence of hyperacusis, in part due to the degree of variation in the term's definition. Reported prevalence in children and adolescents ranges from 3% to 17%. While there are no exact numbers, several people have died by suicide due to the severe consequences of the disease. This includes Musician Jason DiEmilio (Azusa Plane). A hyperacusis sufferer in Belgium took his life in 2009, after years of struggling with catastrophic hyperacusis and tinnitus. A local government in Belgium made a short film based on this person's life, to warn others from the dangers of hyperacusis and tinnitus.
In hyperacusis, the symptoms are ear pain, annoyance, distortions, 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 only one or both ears. Hyperacusis can also be accompanied by tinnitus. Hyperacusis can result in anxiety, stress and phonophobia. Avoidant behavior is often a response to prevent the effects of hyperacusis and this can include avoiding social situations.
Hyperacusis is most often characterized by a sensitivity to sound, where the perception of loudness is much greater than for a typical person; it is often associated with certain volumes and/or frequencies. Hyperacusis can occur in children and adults, and can be either "short-term" in a duration of weeks to less than a year before recovery, or, less-commonly, "long-term", spanning years and in some cases becoming permanent.