Sudden sensorineural hearing loss (SSHL) can be a frightening experience for anyone who has gone through it. But many people are unaware of how critical it is to seek urgent medical care when it occurs. The onset usually takes place within the span of 72 hours. Hearing is reduced by more than 30 decibels over at least three contiguous frequencies, and often affects only one ear. SSHL is associated with dizziness in 25% of patients. Tinnitus (sensations of ringing in the ear) is also common. According to the National Institute on Deafness and Other Communication Disorders, approximately 4,000 new cases of SSHL occur each year in the United States. It can affect anyone, but it most often happens to people between the ages of 30 and 60.