Diagnosis and treatment of sudden sensorineural hearing loss

Nationwide epidemiological surveys of idiopathic sudden sensorineural hearing loss (SSNHL) have been performed five times by the Research Committee of the Ministry of Health and Welfare or the Ministry of Health, Welfare and Labour in Japan. These surveys included patients who had SSNHL in 1972, 1987, 1993, 2001, and 2012. Using the criteria for the grading of hearing loss in SSNHL or the criteria for grading the degree of hearing recovery after SSNHL established by the Research Committee, we compared the outcomes of SSNHL between the five nationwide surveys. The results revealed that the outcomes of SSNHL have not changed in the past 40 years. In 1972, 88% of patients received steroids, but none received prostaglandin E₁ (PGE₁). The use of PGE₁ has increased since the 1980s, but its effect on SSNHL may not be significant. Intratympanic steroid injection has been introduced recently for the treatment of SSNHL, but it does not seem to be used widely in Japan. Intratympanic therapy that can reduce the total amount of steroids administered will be used more frequently if the true effects and indications for this therapy are known. Elucidation of the etiologies of SSNHL and development of treatments specific for these etiologies are expected.