Definite and probable etiologies included: ototoxic effects of antibiotics (n = 12) or chemotherapy (n = 2); post-infectious due to Lyme disease (n = 2), cerebral malaria infection (n = 1), herpes infection (n = 1), meningitis (n = 6), or neuritis (n = 4); head trauma (n = 5); inherited by DFNA9 gene mutation (n = 13) or other gene mutations (n = 10); bilateral Menière’s disease (n = 6); autoimmune disease (n = 2). Here, COCH is linked to autoimmune disease.