The severe type of idiopathic sudden sensorineural hearing loss (ISSHL) was treated with genetic recombination interferon alpha-2a (alpha-IFN) (3 million IU/day for 10 days) plus cortico-steroid, and the results were significantly better than those obtained by conventional treatment with cortico-steroid, vitamins, and vasodilators. Assays for 2'-5' oligoadenylate synthetase (2-5 AS), one of the indices of circulating anti-viral activity were performed patients before and on the third day of IFN therapy, and the levels were found to correlate well with the degree of their hearing improvement. These results suggest that viral infections may be related to the etiology of the severe type of ISSHL and that alpha-Interferon is useful in its treatment.
