Sudden bilateral sensorineural hearing loss.

Most cases of sudden sensorineural hearing loss (SHL) remain idiopathic, and the majority are unilateral. From 1989 to 1993, 823 patients with sudden SHL were evaluated. Of these, 14 (1.7%) had sudden bilateral SHL. We reviewed the charts of these 14 patients to compare sudden bilateral SHL with sudden unilateral SHL. Usually, bilateral SHL was asymmetric. Most bilateral cases received combined steroid and vasodilator treatment, while unilateral cases were more likely to receive only one of these treatments. By audiological criteria, 67% of bilateral SHL cases improved, while the improvement rate in unilateral SHL was 52%; however, this difference was not statistically significant. In bilateral SHL patients showing improvement, both ears responded. Bilateral SHL patients were older at the onset of hearing loss, had a higher incidence of vascular disease, and were more likely to have positive antinuclear antibody titer. Recognition of similarities and differences between sudden unilateral and bilateral SHL can help in counseling patients.