[The value of the ratio of--SP/AP in diagnosing Ménière's disease].

To further explore the diagnostic value of the ratio of--SP/AP (> 0.4) in Ménière's disease, the EcochG results from 70 (76 ears) cases with Ménière's disease were compared to that of 49 cases with sudden hearing loss(SHL), noise induced hearing loss(NIHL), ototoxic hearing loss, and 20 normal hearing person. The effects of different stimulus intensities and the degree of hearing loss on the detectable rate of--SP, the ratio of--SP/AP and its feature in the above mentioned disease were analysed. The results indicated: 1. The mean ratio of--SP/AP was 0.39 +/- 0.02 in normal person on 75 dB nHL stimulus level, while it was larger than 0.45 in SHL and NIHL on 75 dB and 65 nHL stimulus level respectively. 2. There was a rapid descending trend of the ratio of--SP/AP with stimulus level from 65 to 55 dB nHL in all ears except Ménière's cases, which was correlated with stimulus level as well as the degree of hearing loss. 3. The mean ratio of--SP/AP presented linear increase when stimulus level was < or = 75 dB nHL, and when stimulus level was > 75 dB nHL, the mean ratio of--SP/AP no longer presented linear increase and could even decrease, it suggested stimulus level on 75 dB nHL could be used as the diagnostic stimulus level. 4. If the degree of hearing loss exceeded 80 dB HL, the ratio of--SP/AP > 0.4 had no practical significance in diagnosis.