对侧抑制效应对强声所致耳蜗听力功能降低的影响

背景耳声发射是了解听觉功能受损情况的敏感测量方法,而对侧抑制可改变耳蜗的功能状态.目的了解对侧抑制效应对噪声暴露后畸变产物耳声发射( DPOAE)听力图幅值的影响. 设计自身对照的前瞻性研究. 地点和对象在同济医科大学协和医院完成,耳科正常人20例 40 耳,男 9例,女 11例. 干预对受试者以宽带噪声为对侧抑制声 (60dB SPL), 105 dB SPL 2 kHz窄带噪声暴露 10 min,以 L1=70 dB SPL,L2=60 dBSPL,f2/f1=1.21的初始音进行 DPOAE听力图测试观察. 主要观察指标 DPOAE幅值.结果噪声暴露可引起暴露声以上各频率测量点的 DPOAE 2f1-f2反应幅值显著性降低(t=5.468,4.984,4.796,5.966,3.546,P均 < 0.05),以暴露声半倍频 f2频率处(f2=3kHz)降低最为显著 (t=4.984,P=0.000 02). 而对侧抑制效应主要表现在 2kHz 测量点,使此处幅值显著降低 (t=3.148,P=0.003).暴露后存在对侧抑制与否对2～ 6 kHz f2频率处的 2f1-f2幅值改变具有明显影响(t=5.452,4.037,4.798,5.964,3.564,P 均 < 0.001). 结论 DPOAE听力图测试具有较好的频率特异性和高度敏感性,能特异而敏感地反映出对侧抑制和噪声暴露的效应.对侧抑制效应明显增加了DPOAE测量对强声所引起的耳蜗功能降低的敏感性.

Effect of contralateral acoustic suppression on the hearing impairment of cochlea induced by loud noise

BACKGROUND:Otoacoustic emissions is a sensitive measurement method for understanding auditory,however,the contralateral acoustic suppression the functional status of cochlea. OBJECTIVE:To investigate the effect of intensive noise exposure and contralateral acoustic suppression(CAS) on distortion otoacoustic emisson(DPOAE) gram amplitude and its sensitivity. DESIGN:The design is self-controlled and prospective. SETTING and PARTICIPANTS:The experiment was completed in Union Hospital of Tongji University.Forty ears of 20 normal volunteers(9 males and 11 females) were selected. INTERVENTION:Forty ears of 20 normal acouesthesia volunteers were exposed under narrow band noise(NBN)(105 dB SPL,2 kHz central frequency) and investigated by using DP-gram measurement with primates of L1=70 dB SPL,L2=60 dB SPL,f2/f1=1.21 with or without CAS of 60 dB SPL WN.The main outcome measure was DPOAE amplitude. RESULTS:The DPOAE 2f1-f2 amplitude of every f2 frequency measured decreased significantly(t=5.468,4.984,4.796,5.966,3.546,P=0.000 003,0.000 02,0.000 03,0.000 000 6,0.001) with a most significant decrease on the half octave frequency(f2=3 kHz)(t=4.984,P=0.000 02). CAS showed most significant effect on 2 kHz of f2 frequency and deceased amplitude significantly(t=3.148,P=0.003).After noise exposure, the changes of 2f1-f2 amplitude on 2-6 kHz f2 frequency sites showed significant difference between groups with and without CAS(t=5.452,4.037,4.798,5.964,3.564,P=0.000 001,0.000 7,0.000 04,0.000 5,0.001). CONCLUSION:DP-gram measurement has better frequency specificity and high sensitivity and can specifically and sensitively reflect the effects of CAS and noise exposure.CAS can increase sensitivity of DPOAE-gram measurement to the cochlear function induced by noise exposure.