Heidari Phd Fatemeh, Pourbakht Akram, Kamrava Seyed Kamran, Kamali Mohammad, Yousefi Abbas
Department of Audiology, School of Rehabilitation Sciences, IranUniversity of Medical Sciences,Tehran, Iran .
Department of Audiology, Schoolof Rehabilitation, Shahid BeheshtiUniversity of Medical Sciences,Tehran, Iran.
Iran J Child Neurol. 2018 Spring;12(2):58-65.
Cochlear microphonic (CM) is a cochlear AC electric field, recorded within, around, and remote from its sources. Nowadays it can contribute to the differential diagnosis of different auditory pathologies such as auditory neuropathy spectrum disorder (ANSD). This study compared CM waveforms (CMWs) and amplitudes with broad and narrow band stimuli in 25 healthy male young adults Wistar rats.
MATERIALS & METHODS: This experimental study was accomplished in the School of Rehabilitation Sciences of Iran University of Medical Sciences, Tehran, Iran (April, 2016). Using an extratympanic technique in ECochG (Electrocochleography) recording, CMWs in response to click and tonal stimuli with different octave frequencies were recorded at a high intensity level in subjects. The CMW amplitudes were calculated by a graphical user interface (GUI) designed in MATLAB.
The CMW magnitude increased upon an increase in bandwidth stimulation. CM amplitude with click stimulation was larger than tonal stimuli. Across tonal stimuli, the CMW amplitudes at lower frequency tones were larger than those at higher frequency tones. Those findings were statistically significant (<0.001).
CMW amplitude with click as broadband stimulus was larger than those with tone bursts as narrowband stimulation. Click stimulation due to the width of spectral involves greater regions of cochlear partition. Therefore, CMW most likely is a reflection of spatial summation of voltage drops generated by hair cell groups in response to acoustic stimulation. In order to production nature of CM potentials as well as their very small magnitudes especially with tonal stimuli, thus, we recommend using click stimulation for CM potential recording.
耳蜗微音电位（CM）是一种耳蜗交流电场，可在其源内部、周围及远处记录到。如今，它有助于不同听觉病理状态的鉴别诊断，如听觉神经病谱系障碍（ANSD）。本研究比较了25只健康雄性成年Wistar大鼠在宽带和窄带刺激下的CM波形（CMWs）和振幅。
本实验研究于2016年4月在伊朗德黑兰医科大学康复科学学院完成。在耳蜗电图（ECochG）记录中采用鼓膜外技术，在高强度水平下记录受试者对不同倍频程频率的短声和纯音刺激的CMWs。CM振幅通过在MATLAB中设计的图形用户界面（GUI）计算得出。
随着带宽刺激增加，CMW幅度增大。短声刺激的CM振幅大于纯音刺激。在所有纯音刺激中，低频纯音的CMW振幅大于高频纯音。这些结果具有统计学意义（<0.001）。
作为宽带刺激的短声刺激的CMW振幅大于作为窄带刺激的短音刺激的CMW振幅。由于频谱宽度，短声刺激涉及耳蜗分隔的更大区域。因此，CMW很可能是毛细胞群响应声刺激产生的电压降空间总和的反映。鉴于CM电位的产生性质及其非常小的幅度，尤其是对于纯音刺激，因此，我们建议使用短声刺激进行CM电位记录。
