What is Sudden Hearing Loss?
Sudden hearing loss (SHL) is defined as greater than 30 dB hearing reduction, over at least three contiguous frequencies, occuring over 72 hours or less. It occurs most frequently in the 30 to 60 year age group and affects males and females equally. Although called sudden, it seems unlikely that hearing loss is abrupt but rather it probably evolves over a few hours. SHL can affect different people very differently. SHL is usually unilateral (that is, it affects only one ear); and is often accompanied by tinnitis. vertigo, or both. The amount of hearing loss may vary from mild to severe, and may involve different parts of the hearing frequency range. SHL may be temporary or permanent. About one third of people with SHL awaken in the morning with a hearing loss.
