For most people who experience hearing loss, the condition comes on gradually over a period of years. In rare cases, an abrupt loss of hearing occurs with little or no warning. This condition, known as sudden sensorineural hearing loss (SSHL), is defined as a hearing reduction of 30 dB or greater over three contiguous frequencies, occurring over a period of 72 hours or less.
Causes
There are over 100 possible causes for SSHL. These include infectious diseases, head trauma, abnormal tissue growth, circulatory problems, neurologic disorders, toxic causes, immunologic diseases, inner ear problems such as Meniere’s disease, and ototoxic medications. Certain groups of antibiotics, in particular, have been shown to destroy the hair cells of the cochlea, causing sudden deafness that is often permanent in nature. These must be used with extreme caution and should be avoided unless they are the only viable course of treatment for a life-threatening illness. Risk factors for SSHL include a prior diagnosis of meningitis, a recent head injury, ear infection, exposure to loud noise, a sudden change in pressure, and starting a new medication.