The word hyperacusis, generally referring to cochlear hyperacusis, means an over-sensitivity or intolerance for typically encountered sounds every day, such as the refrigerator running. However, vestibular hyperacusis is equally disabling for the lives it affects, albeit in different ways. Dr. Marsha Johnson, an audiologist in Oregon, was the first to widely publicize vestibular hyperacusis in her many articles. On October 25th 2010, the audiologist Dr. Teddy Caramoan Cheng presented a selected number of studies relating to Vestibular Hyperacusis at the UK's first Hyperacusis Seminar held at the Royal Surrey County Hospital, Audiology Department. The Vestibular Hyperacusis presentation explored the anatomical, physiological, neurotological, audiological, ototoxicity-related, vestibulopathic, and presbyacusic evidence towards creating a Vestibular Hyperacusis model.
Vestibular hyperacusis is a mix-up between the brain's maintenance of upright balance and the sense of hearing. Instead of perceiving sounds as intolerable, the brain perceives them as movement sensations, disturbance to postural balance and/or visual focus (fixation). It is different from cochlear hyperacusis in that many people with vestibular hyperacusis can handle normal sounds just fine, but certain pitches and sounds that have higher than 85 decibels may trigger these sensations. People who have vestibular hyperacusis rarely have tinnitus co-morbidly, while as many as 86% of all CH sufferers have tinnitus.
While symptoms of cochlear hyperacusis range from ear discomfort at normal sounds to panic reactions at soft sound, symptoms of vestibular hyperacusis are generally linked to balance and feelings of movement. Someone suffering from vestibular hyperacusis may feel dizzy, sick to their stomach, or confused when in the presence of loud noises. Fatigue, anxiety, confusion, and even loss of consciousness are also common. Headaches, feelings of pressure in the ear or clutching for something to hold onto in a noisy environment is not unusual. Around 1998, the exploration of CT-Scan images in vestibular hyperacusis patients led to discovery of a rare condition called, "Superior Semi-Circular Canal Dehiscence Syndrome" or SCDS. Clinically, a tell-tale sign of SCDS is either having Tullio's Phenomenon, i.e. sound causing a spinning sensation or abnormal eye movements called nystagmus, or Hennebert's sign (nystagmus following applied pressure into the external auditory canal)
Where SCDS is confirmed in a comprehensive CT-scan, surgery may be offered to correct the dehiscence. Many cases of vestibular hyperacusis have the diagnosis of an unknown cause (i.e. idiopathic). Thus, most therapies that specifically target vestibular hyperacusis involve vestibular therapy, as with any vestibular disorder. An occupational therapist usually performs this type of therapy.