Background and Aim: Sudden Sensorineural Hearing Loss (SSNHL) is an emergency situation, and is one of the most controversial subjects in domain of otolaryngology. In this article, we have analyzed some Epidemiologic Characteristics, clinical features, audiological Characteristics, and other findings in routine serological tests and MRI of 48 cases with SSNHL ,who came or were referred to us in the past 2 years. Study design: Cross sectional.

Materials and Methods: In 48 patients with chief complaint of SSNHL, from June 2003 to Feb. 2005, who were admitted in clinic of otolaryngology- in Kashani Hospital -Isfahan- Iran, physical examination and history taking, audiological evaluation, MRI,and serological tests were performed in a similar way , and data were analyzed by SPSS software.

Results: From 48 cases(M:28 ,F:20) with mean age of 40.9(+/-15.9) years, left ear was involved in 26 cases (54.1%) ,and right ear in 19 cases (39.5%) ,and in 3 cases (6.3%),both sides were involved. The severity of hearing loss was “subjectively” HIGH in 78% of patients, and the mean threshold of hearing had been calculated as 69 dB. The most common pattern in pure tone audiometry curves ,was ‘flat pattern’(75%) ,and then ,’down sloping pattern’(16%).The most adjunctive clinical symptom was “tinnitus”(in 78.7%), and 40% of patients had “true vertigo”. 44.4% of our patients had some evidences of upper respiratory tract infections (URIs) during recent 2 weeks. Positive family history, smoking, alcohol intake ,oral contraceptive and ototoxic drugs consumption were uncommon. 24% of cases (11 of 39) had increased ESR, and 100% of 39 patients had negative VDRL. Diabetes mellitus was the most common underlying disease (in 6 cases).From 20 patients ,who were succeeded to perform brain and ear MRI, 2 cases had tumor in internal auditory canal and cerebellopontine angle.

Conclusion: SSNHL has some limitations in being studied histopathologically or in the form of clinical trials, and in nearly all of its aspects there are some mysteries to be cleared. Our ‘Iranian’ patients demonstrated some special characteristics.