摘要
目的了解响度重振与耳蜗微音电位(cochlearmicrophonic,CM)及耳聋预后之间的关系,探讨重振的形成机制。方法对104例一耳正常,另一耳为感音性听力下降并有响度重振的患者施行双耳CM测试,测试频率为0.5、1kHz,以高频下降为主者加测2、4、8kHz。将患者初诊时纯音听阈、双耳CM检测阈值与最终稳定之后的纯音听阈相比较,为便于分析结果,本文提出了CM分型标准:Ⅰa型:患耳CM检测阈值<健耳,阈值差≤10dB;Ⅰb型:双耳CM检测阈值相等,检测阈≤55dBSPL。Ⅱa型:患耳CM检测阈值>健耳,差值≥15dBSPL;Ⅱb型:患耳检测阈值为60～75dBSPL。Ⅲ型患耳CM检测阈值>75dBSPL或引导不出。结果听力正常组各频率CM绝对振幅在不同个体差异较大,但同一正常个体双耳之间CM幅值及阈值则较接近并稳定,因此不采用平均值而仅以同一个体正常一侧CM幅值的大小来评价患耳的CM幅值。重振耳CM有增大和延长现象。104例单侧感音性聋,95例(91.3%)主观检测有重振的频率出现CM振幅明显增大,其中34例在CM增大同时伴有CM延长(5.8%),与正常耳比较延长1～11个周波,平均时间延长(5.2±2.5)ms。初诊时即遵照CM分型标准分类,随后经6个月以上随诊,发现CMⅠ型预后明显好于Ⅱ型和Ⅲ型,Ⅰ型治疗总有效率高达78.19%;Ⅱ型多数预后不佳,治疗有效率仅为2.5%;Ⅲ型治疗均无效;将CMⅠ型与Ⅱ型做预后比较,组间差异具有显著性意义(x2=53.709,P<0.001);Ⅰ型与Ⅲ型比较,差异亦具显著性意义(x2=21.444,P<0.001);Ⅱ型与Ⅲ型比较,差异无显著性(x2=0.230,P>0.05)。睡眠状态下CM幅值略有增大,与此同时CM阈值减低。结论CM检测可为了解重振发生机理以及重振与CM和耳聋预后之间的关系提供可靠的客观信息。听力下降耳CM幅值正常或增大为重振所特有客观指征。
OBJECTIVE To determine the relationship among loudness recruitment, cochlear microphonics and the prognosis of some inner ear disorders. To investigate the mechanism of loudness recruitment. METHODS Cochlear microphonics （CM） was recorded bilaterally in 104 cases of unilateral sensory hearing loss with loudness recruitment. Test frequencies were mainly 0.5 and lkHz. Additional 2, 4 and 8kHz tests were adapted for those patients with high-frequency hearing loss. The initial pure tone audiogram（PTA） and type CM test results were compared with the final stable PTA. CM was classified into three types： type Ⅰ a ： CM threshold of affected ear 〈 that of sound ear; type Ⅰ b ：Bilateral CM thresholds are equal or≤55 dB SPL; type IIa： CM threshold of affected ear is 〉 that of sound ear, the threshold difference≥15dB SPL; type Ⅱb： CM threshold of affected ear is between 60 and 75dB SPL; type Ⅲ： CM threshold of affected ear 〉 75dB SPL or no response. RESULTS The individual differences of CM absolute amplitudes among the normal hearing ones at different frequencies are distinct, but bilateral CM amplitudes in same person are almost uniform and stable. Enlarged and prolongated CM was found in ears with loudness recruitment .Of 104 cases with unilateral hearing loss, CM were enlarged and prolongated at corresponding frequencies with loudness recruitment in 95 cases（91.3 %）.The prognosis of cases with CM type Ⅰ was better than those with types Ⅱ and Ⅲ. The effective rates of treatment were 78.19 % in typeⅠ, 2.5 % in type Ⅱ, and none in type Ⅲ. There were significant differences among them. CM was slightly enlarged during sleep,and the detected threshold of CM is less than that of the awake condition. CONCLUSION CM offers the reliable information for the mechanism of loudness recruitment and is also useful for understanding the relationship among loudness recruitment, cochlear microphonics and prognosis. CM may be taken as a valuable parameter for evaluating prognosis.
出处
《中国耳鼻咽喉头颈外科》
北大核心
2006年第3期161-164,共4页
Chinese Archives of Otolaryngology-Head and Neck Surgery
基金
北京市自然科学基金资助项目(7982009)
关键词
听觉过敏
耳蜗微音电位
预后
Hyperacusis
Cochlear Microphonic Potentials
Prognosis
