Also known as hyperacusis dolorosa, auditory hyperaesthesia, dysacusis, dysauris, loudness discomfort, loudness intolerance, over-recruitment, pseudo-recruitment, and phonophobia. The term hyperacusis comes from the Greek words huper (to exceed a certain boundary) and akouein (to hear). It translates loosely as 'hypersensitivity to sound'. The French-Greek neologism hyper-cousie was introduced in or shortly before 1921 by the French military surgeon and otologist Jean-Marie-Gaspard Itard (1774-1838). It was later changed to the etymologically correct form hyperacousie. The term hyperacusis is used to denote a decreased loudness tolerance, i.e. a condition in which externally generated auditory percepts are perceived as either disproportionally loud (generalized hyperacusis with normal hearing), unpleasant (hyperacusis with recruitment), or dangerous (hyperacusis with phonophobia). However, other types and classifications of hyper-acusis have also been proposed. Hyperacusis can be classified as a type of "hyperaesthesia. A variant of hyperacusis in which intense sounds are perceived as louder than normal is called " audiosensitivity. Pathophysiologically, hypera-cusis is associated primarily with paralysis of the stapedius muscle. In some 90% of the cases there is comorbidity with "tinnitus. Other conditions associated with hyperacusis are migraine, postconcussion syndrome, "post-traumatic stress disorder, infantile autism, depressive disorder, Bell's palsy, and conditions affecting either the lower motor neurone facial nerve (N. VII) or the nerve to the stapedius. The term hyperacusis is used in opposition to the term hypacusis.
References
Gordon, A.G. (1986). Abnormal middle ear muscle reflexes and audiosensitivity. British Journal ofAudiology, 20, 95-99.
Gordon, A.G. (2000). "Hyperacusis" and origins of lowered sound tolerance. Journal of Neuropsychiatry and Clinical Neuroscience, 12, 117-118.
Itard, J.-M.-G. (1821). Traité des maladies de l'oreille et de l'audition. Paris: Méquignon Marvis.
Dictionary of Hallucinations. J.D. Blom. 2010.