Halmagyi G Michael, Aw Swee T, McGarvie Leigh A, Todd Michael J, Bradshaw Andrew, Yavor Robyn A, Fagan Paul A
Neurology Department, Royal Prince Alfred Hospital, Sydney, and the Otolaryngology Department, St Vincent's Hospital, Sydney, Australia.
J Laryngol Otol. 2003 Jul;117(7):553-7. doi: 10.1258/002221503322113003.
This is a report of a patient with an air-bone gap, thought 10 years ago to be a conductive hearing loss due to otosclerosis and treated with a stapedectomy. It now transpires that the patient actually had a conductive hearing gain due to superior semicircular canal dehiscence. In retrospect for as long as he could remember the patient had experienced cochlear hypersensitivity to bone-conducted sounds so that he could hear his own heart beat and joints move, as well as a tuning fork placed at his ankle. He also had vestibular hypersensitivity to air-conducted sounds with sound-induced eye movements (Tullio phenomenon), pressure-induced nystagmus and low-threshold, high-amplitude vestibular-evoked myogenic potentials. Furthermore some of his acoustic reflexes were preserved even after stapedectomy and two revisions. This case shows that if acoustic reflexes are preserved in a patient with an air-bone gap then the patient needs to be checked for sound- and pressure-induced nystagmus and needs to have vestibular-evoked myogenic potential testing. If there is sound- or pressure-induced nystagmus and if the vestibular-evoked myogenic potentials are also preserved, the problem is most likely in the floor of the middle fossa and not in the middle ear, and the patient needs a high-resolution spiral computed tomography (CT) of the temporal bones to show this.
这是一份关于一名存在气骨导差患者的报告。该患者10年前被认为患有因耳硬化症导致的传导性听力损失，并接受了镫骨切除术治疗。现在发现，该患者实际上因上半规管裂而出现了传导性听力增益。回顾过去，患者自能记事起就一直经历着耳蜗对骨导声音的超敏反应，以至于他能听到自己的心跳、关节活动声，以及放在脚踝处的音叉声。他还对气导声音存在前庭超敏反应，伴有声音诱发的眼球运动（图利奥现象）、压力诱发的眼球震颤以及低阈值、高振幅的前庭诱发肌源性电位。此外，即使在镫骨切除术后及两次修复手术后，他的一些声反射仍得以保留。该病例表明，如果存在气骨导差的患者声反射得以保留，那么就需要检查其是否存在声音和压力诱发的眼球震颤，并进行前庭诱发肌源性电位测试。如果存在声音或压力诱发的眼球震颤，且前庭诱发肌源性电位也得以保留，那么问题很可能出在中颅窝底部而非中耳，患者需要进行颞骨高分辨率螺旋计算机断层扫描（CT）以明确这一点。
