Preclinical animal behavioral models of hyperacusis and loudness recruitment

Hyperacusis is a loudness intolerance disorder in which everyday sounds are perceived as intolerably loud, annoying, fearful, or even painful. While hyperacusis is often considered exclusively as a hearing problem, it is associated with a broad spectrum of auditory (tinnitus), vestibular, and other neurological disorders such as autism, Williams syndrome, fibromyalgia, migraine, and a host of other sensory hypersensitivity disorders. The underlying mechanisms and biological basis of hyperacusis in its different manifestations are poorly understood largely due to the lack of valid behavioral models. In this review, we discuss recent advances in the development of behavioral models that have been used to measure various forms of hyperacusis and the genetic models and experimental conditions that have been employed to induce hyperacusis in animals.