RESUMO
OBJECTIVES: Hearing loss in the early stages of Meniere's disease is characterized by a fluctuation in the audiometric pattern limited to the low frequencies, and then, during the disease's evolution, the hearing loss involves the medium and high frequencies. As far as the prevalence of different types of audiometric curves is concerned, there is no agreement among the various studies. The study of audiometric evolution in the course of the disease has been limited owing to the difficulties in following a relevant number of patients for a long period of time. The aim of the present study was to compare the auditory level and audiometric pattern evolution in a significant number of patients suffering from Meniere's disease who had undergone long-term follow-up (at least 10 years). METHODS: The study considered 380 patients with a confirmed diagnosis of Meniere's disease. The audiometric data were collected at the onset of the disease and after 5 and 10 years. Four patterns were considered: peak, rising, falling, and flat. Audiometric evolution analysis in four stages, defined by the guidelines of the American Academy of Otolaryngology-Head and Neck Surgery, was evaluated. RESULTS: At the onset, in 190 cases, the audiometric pattern was a peak curve, with fluctuation of the threshold in 68% of cases. The mean threshold shift for the 500 to 3000 Hz range was between 26 and 40 dB. After 5 years, a peak type (41.9%) or a flat type (42.9%) was observed; the pure-tone average (PTA) ranged between 26 and 40 dB in 47.9% and between 41 and 70 dB in 51.8% of cases. After 10 years, in most cases (57.9%), a flat curve was observed, and the PTA in 100% ranged between 41 and 70 dB. CONCLUSION: The most common audiometric pattern at the onset of the disease is the peak type; long-term transformation of the initial audiometric pattern into a flat curve has been confirmed. High-frequency involvement seemed to be related more to Meniere's disease duration than to the influence of aging on hearing loss.