Sudden hearing loss (SHL) is defined as greater than 30 dB hearing reduction, over at least three contiguous frequencies, occurring 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 tinnitus, 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.
Since it is usually followed by vertigo, there are some symptoms for it. However, it is sudden for a person who heard its entire life perfectly, and then just wakes up one morning and can’t hear. The symptoms that a person who has experienced sudden hearing loss, are: feeling dizzy and lightheaded, when you make sudden movements it feels like the whole room is spinning around you. Afterwards, most people are sweating and feel nausea. This can, for some reason, cause sudden hearing loss.