An analysis of audiogram patterns of patients with intractable Meniere's disease

Purpose: The audiometric pattern of Meniere's disease is often characterized as having a low-tone loss in the early stage, followed by a flat audiometric pattern in the late stage. However, other audiogram patterns including peak and dip have also been described in the literature. By selection of a large number of patients with intractable Meniere's disease receiving endolymphatic sac surgery, the preoperative audiogram patterns sere analyzed. Materials and methods: From January 1990 to July 1997, 198 patients with 201 ears having intractable Meniere's disease and receiving endolymphatic sac operation were included. Only preoperative data were studied, and for each patient, age at onset, gender, ear involved, pure tone average and the audiogram pattern were recorded anti analyzed. The audiogram patterns were classified into five types, namely peak, dip, and fiat, rising and falling. The peak patterns were further divided into 3 subtypes by the hearing level. Peak A is within normal limits (0 to 25 dB BL), peak B falls within the range of 26 to GD dB HL and peak C exceeds 60 dB HL. Results: Peak pattern represents 25.9% (52/201), dip pattern 8.5% (17/201), nat pattern 17.4% (35/201), rising pattern 7.5% (15/201) and falling pattern 40.8% (82/201) respectively. And among the peak pattern, "peak A" represents 23.1% (12/52), "peak B" 61.5% (32/52) and "peak C" 15.4% (8/52). There is no statistical significance for the differences among the patterns concerning the ear involved, the gender, the age at onset and pure tone average. Conclusion: Endolymphatic hydrops can eventually affect each turn of the cochlea in its course, and result in a variety of audiogram patterns including the peak, dip, flat; rising, and falling patterns. The peak pattern may reflect endolymphatic hydrops and the falling pattern may be characteristic to late Meniere's disease.