Sudden sensorineural hearing loss (SSHL), commonly known as sudden deafness, occurs as an unexplained, rapid loss of hearing—usually in one ear—either at once or over several days. A loss of 30 decibels in three connected frequencies, over a period of three days, is considered SSHL. It should be considered a medical emergency. 

Only 10 to 15 percent of the people diagnosed with SSHL have an identifiable cause. The most common causes are:

Causes of Sudden sensorineural hearing loss

  • Infectious diseases
  • Trauma, such as a head injury
    Sudden sensorineural hearing loss.ent

    Sudden sensorineural hearing loss

  • Autoimmune diseases such as Cogan’s syndrome
  • Ototoxic drugs (drugs that harm the sensory cells in the inner ear)
  • Blood circulation problems
  • A tumor on the nerve that connects the ear to the brain
  • Neurologic diseases and disorders, such as multiple sclerosis
  • Disorders of the inner ear, such as Ménière’s disease


Audiometry tests will be performed to evaluate your hearing more thoroughly and precisely. A series of different sounds and volume levels may be sent to each ear individually. This can help determine the level at which your hearing begins to fade.

An MRI scan may also be ordered to look for any abnormalities in the ear, such as tumors or cysts. 

Anyone who experiences SSHL should visit a doctor immediately, as delaying SSHL diagnosis and treatment may decrease the effectiveness of treatment.
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  • Chin CJ, Dorman K. Sudden sensorineural hearing loss. CMAJ. 2017 Mar 20;189(11):E437-E438.
  • Amarillo E, Navarro A, Hernández-García E, Plaza G. Intratympanic steroids for combined treatment of idiopathic sudden hearing loss: when is it too late? Acta Otolaryngol. 2019 Jul;139(7):632-635.