In the 250 Hz pure-tone test:A-B gap were observed in 126 ears(126/154,81.8%) with the different hearing loss degree: 1 ear mild, 11 ears moderate, 19 ears moderate severe, 40 ears severe and 53 ears profound.

• 纯音测听检查:在250Hz处；126耳(81.；8%25)存在骨气导差；按听力损失程度分类:轻度1耳；中度12耳；中重度18耳；重度38耳；极重度57耳;