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测听时耳机压迫外耳道使之塌陷,可影响纯音听阈,这种现象在声阻抗检查中亦可能遇到。为了提请注意,特介绍一病例如下: 病人是7岁女孩,未能通过学校的听力筛选,纯音测听左耳在10分贝水平;右耳在30～35分贝。家长从未发现患儿听力有何困难,但言语接受阈左耳为40分贝,且前后反应一致,看来又不像假性听力减退。声阻抗检查两耳鼓室曲线都是A型,两耳交叉声反射1000赫75分贝均可引出,声反射无衰减现象。各项结果均正常,因此考虑到纯音测听时耳郭受压阻塞外耳道的可能。于是用耳模放入外耳道内,以除外耳机压迫闭锁外耳道的因素。复查气导听阈,两耳全部正常。值得注意的是当复查交叉声反射时,左耳声反射阈明显升高,达110分贝(HL)。将耳模放入外耳道复查,在80分贝就能引出反射,证明声反射阈增高亦与外耳道塌陷有关。
Earphone compression when listening to the external auditory canal make it collapse, can affect pure tone hearing threshold, this phenomenon may also be encountered in the acoustic impedance test. In order to draw attention, a case was introduced as follows: The patient was a 7-year-old girl who failed to pass the school’s hearing screening. The pure tone audiometry left ears were at 10 decibels; the right ears were 30-35 decibels. Parents have never found any difficulty in hearing children, but speech threshold left ear to accept 40 dB, and before and after the reaction, it seems not like pseudo-hearing loss. Acoustic impedance examination Both ear tympanogram curves are type A, both ears cross-echo 1000 Hz 75 dB can lead to sound reflection without attenuation phenomenon. The results are normal, so consider the pure tone audiocarburic obstruction of the external auditory meatus possible. So with the ear mold into the external auditory canal, with the exception of the earphone pressure to lock the external auditory canal factors. Review the air guide hearing threshold, both ears all normal. It is noteworthy that when reviewing the cross-reflex, left aural reflex threshold increased significantly, up to 110 decibels (HL). The ear mold into the external auditory canal, the reflex can lead to 80 dB, to prove that the acoustic reflex threshold is also related to the collapse of the external auditory canal.