[Review of papers on the efficacy of the treatment in sudden deafness reported between 1989 and 1998 in Japan].

We reviewed hearing recovery in 3,430 patients with sudden deafness reported between 1989 and 1998 in Japan, evaluated using standards of the Research Group on Sudden Deafness of the Ministry of Health and Welfare of Japan. Complete recovery was seen in 30.8%, marked in 24.7%, slight in 23.3% and no change in 21.8%. No remarked improvement in recovery of hearing was seen in patients with sudden deafness in these 10 years. The number of patients studied in evaluating the efficacy of therapies may thus affect results. Complete recovery from sudden deafness was nearly 30% in proportion to the increase of number of patients studied in the literature. At least 200 patients should be studied to make a reliable evaluation.