Sudden hearing loss (SHL) is defined as more than 30 dB hearing loss, over at least three contiguous frequencies, occuringwithin 72 hours . It occurs most frequently in the 30 to 60 year age group and affects males and females equally.Mostly Unilateral it is often accompanied with tinnitis. vertigo, or both. Hearing loss may be mild to severe and also 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. CAUSES : Idiopathic Viral Partial or complete blockage of the blood circulation of the inner ear Vascular Spasm Rupture of the delicate inner ear membrane and fistulae of the round and/or oval window. Round and oval window ruptures are reported to occur when pressures from within (cerebrospinal pressure) or without (middle ear pressure) suddenly increase causing breaks in the cochlear membrane, resulting in sudden hearing loss.