Prognostic factors in sudden sensorineural hearing loss: our experience and a review of the literature

OBJECTIVES: We investigated prognostic factors in sudden sensorineural hearing loss (SSNHL). METHODS: Our study group consisted of 133 patients with SSNHL who were treated at our department between 1980 and 2000. Eighty-one of them (group B) were treated between 1980 and 1996; they received vasodilators and small doses of steroids. The others (52 patients; group A) were treated between 1997 and 2000; they received vasodilators, steroids at high doses, and hyperbaric oxygen. A multivariate stepwise linear regression was used to identify the prognostic factors that were related to hearing improvement as measured by objective change of gain in the overall average (0.5, 1, 2, 4, 6, 8 kHz), the pure tone average (0.5, 1, 2 kHz), the high tone average (4, 6, 8 kHz), and the pure middle tone average (0.5, 1, 2, 4 kHz). The following factors were included in the analysis: group (method of treatment), age, gender, seasonal occurrence of disease, presence of tinnitus and vestibular symptoms, time delay before first visit, type of initial audiogram, and type of caloric reaction. In group A, an additional analysis was conducted to include the results of certain laboratory tests: blood morphology parameters, erythrocyte sedimentation rate, glucose level, coagulogram, lipidogram, thyroid-stimulating hormone, autoantibodies (antimitochondrial antibodies, smooth muscle antibodies, and anti-brush border antibodies), and immunoglobulins G, A, and M. Values for p of less than .05 were considered significant. RESULTS: Our analysis suggests the presence of the following prognostic factors for SSNHL: method of SSNHL treatment (better results in group A); time delay before the start of treatment (better results when treatment started within 10 days of the first symptoms of SSNHL); and type of caloric reactions (worse results in patients with canal paresis). In group A, the factors for poor prognosis for absolute hearing improvement were as follows: delayed treatment, labyrinth responsiveness disorders, and decreased level of thyroid-stimulating hormone. In group A, better hearing improvement was observed in those patients in whom SSNHL was diagnosed in the spring. CONCLUSIONS: A short time delay before starting treatment (within 10 days), treatment with high doses of steroids and hyperbaric oxygen, preserving complete caloric function of the labyrinths, normal function of the thyroid, and seasonal occurrence of the disease in the spring were positive prognostic factors for hearing recovery in SSNHL.