Definite and probable etiologies comprised: ototoxic effects of antibiotics (n = 8) or chemotherapy (n = 1), post-infectious due to Lyme disease (n = 1), Hashimoto’s thyroiditis (n = 1), Herpes infection (n = 1), meningitis (n = 2), inherited, e.g. by DFNA9 gene mutation (n = 7), bilateral Menière’s disease (n = 3), autoimmune disease (n = 1). Here, COCH is linked to Lyme disease.