纯音骨导听阈测试的掩蔽问题  

Probe to the bone-conduction phenomenon

作　　者：曾祥丽[1] 龚树生[1] 钟乃川[1] 

机构地区：[1]华中科技大学附属协和医院耳鼻咽喉科,武汉430022

出　　处：《临床耳鼻咽喉科杂志》2004年第4期204-206,共3页Journal of Clinical Otorhinolaryngology

摘　　要：目的 :通过对一组耳科正常青年人及不同性质的耳聋患者进行韦伯试验 (WT)及骨导掩蔽测试 ,以探讨骨导测试现象的规律 ,为临床测试提供指导。方法 :分别对 2 0例耳科正常青年人及 113例有不同性质听力损失的患者进行WT及骨导掩蔽测试。结果 :当双耳均无传导障碍时 ,骨导听阈取决于双耳耳蜗听敏度 ,WT偏向取决于双耳听敏度之差。不同性质的传导性病变 ,使不同频段的骨导听阈降低。一耳正常 ,另耳为传导性聋时 ,WT 3～ 5个频率偏患耳 ;另耳为耳蜗性聋且气导耳间差大于 4 0dB时 ,患耳骨导越边。双耳传导性聋或双耳混合性聋或一耳传导性聋另耳混合性聋 ,骨导听阈取决于双耳病变的不同性质、不同程度 ,WT偏向无规律。当双耳骨导听阈正常而气导听阈大于耳间衰减时 ,则掩蔽无法实施。结论 :为避免中枢掩蔽和过度掩蔽的影响 ,实验发现 :①双耳均无传导障碍 ,且双耳气导听阈之差大于 4 0dB ,测优势耳骨导时不需掩蔽 ,劣势耳骨导听阈越边 ;②一耳正常、另耳为传导性聋 ,测试患耳骨导时不需掩蔽 ;③若双耳存在传导性病变 ,且骨导听阈正常而气导听阈大于耳间衰减 ,则掩蔽无法实施 ,放弃掩蔽测试。Objective: To probe into the rule of bone-conduction measurment by testing a group of health young students with normal hearing and groups of case with different diseased ears, in order to provide some instructions for clinical audiometry.Method: Subjects included 20 health young students with normal hearing, 113 cases with different hearing loss.We tested all the subjects Weber Test and bone-conduction threshold by masking. Result:Weber Test lateralization dependented on the difference of binanural sensitivity when binaural had no conductive impairment. Different conductive impairment improved bone-conduction response at different frequencies. When monaural had conductive impairment and the other ear normal, there were 3-5 octaves WT lateralizated to the diseased ear. When there were binaural conductive impairments ,bone-conduction response dependented on the nature and degree of the impairment, WT lost the rule. Conclusion: In order to avoid the negative effects of central masking and overmasking,our observations came to the conclusion that some conditions as follow need no masking: ①There are no conductive impairment binaural ,and the air-conduction pure tone threshold (PTT) gap between binaural higer than 40 dB,when we test bone-conduction PTT of better ear,we need no masking,as for the poor ear,it's bone conduction will come cross to the contralateral ear.②When one ear normal and the other is the conductive impairment,need no masking when testing the diseased ear.③There are conductive impairments binaural,bone-conduction PTT is normal, and air-conduction PTT is higher than interaural attenuation,we cann't get a true bone-conduction PTT by masking, but can determine the type of hearing loss and estimate the integrity of the sensory-neural system by other audiometry measurements.

关 键 词：测听法 纯音 骨导掩蔽测试 骨导偏向试验 

分 类 号：R764.04[医药卫生—耳鼻咽喉科]