Zhang Ming
University of Alberta, Edmonton, AB, Canada.
Trends Amplif. 2012 Jun;16(2):117-26. doi: 10.1177/1084713812448547. Epub 2012 Jun 13.
Low-frequency otoacoustic emissions (OAEs) are often concealed by acoustic background noise such as those from a patient's breathing and from the environment during recording in clinics. When using electrocochleaography (ECochG or ECoG), such as cochlear microphonics (CMs), acoustic background noise do not contaminate the recordings. Our objective is to study the response pattern of CM waveforms (CMWs) to explore an alternative approach in assessing cochlear functions. In response to a 14-msec tone burst across several acoustic frequencies, CMWs were recorded at the ear canal from ten normal hearing subjects. A relatively long tone burst has a relatively narrow frequency band. The CMW amplitudes among different frequencies were compared. The CMW amplitudes among different frequencies were compared. Two features were observed in the response pattern of CMWs: the amplitude of CMWs decreased with an increase of stimulus frequency of the tone bursts; and such a decrease occurred at a faster rate at lower frequencies than at higher frequencies. Five factors as potential mechanisms for these features are proposed. Clinical applications such as hearing screening are discussed. Therefore, the response pattern of CMWs suggests that they may be used as an alternative to OAEs in the assessment of cochlear functions in the clinic, especially at low frequencies.
在临床记录过程中，低频耳声发射（OAEs）常常被诸如患者呼吸声和环境噪声等声学背景噪声所掩盖。在使用电耳蜗图（ECochG或ECoG），例如耳蜗微音电位（CMs）时，声学背景噪声不会干扰记录。我们的目的是研究CM波形（CMWs）的反应模式，以探索一种评估耳蜗功能的替代方法。对十名听力正常的受试者在耳道记录其对几个声学频率的14毫秒短音突发的CMWs反应。相对较长的短音突发具有相对较窄的频带。比较了不同频率下的CMW振幅。在CMWs的反应模式中观察到两个特征：CMWs的振幅随着短音突发刺激频率的增加而降低；并且这种降低在低频时比高频时发生得更快。提出了五个因素作为这些特征的潜在机制。讨论了听力筛查等临床应用。因此，CMWs的反应模式表明，它们在临床评估耳蜗功能中，尤其是在低频时，可能用作OAEs的替代方法。
