Department of Otolaryngology-Head and Neck Surgery, University of North Carolina at Chapel Hill, North Carolina 27599, USA.
Otol Neurotol. 2011 Oct;32(8):1370-8. doi: 10.1097/MAO.0b013e31822f09f2.
Cochlear trauma due to electrode insertion can be detected in acoustic responses to low frequencies in an animal model with a hearing condition similar to patients using electroacoustic stimulation.
Clinical evidence suggests that intracochlear damage during cochlear implantation negatively affects residual hearing. Recently, we demonstrated the usefulness of acoustically evoked potentials to detect cochlear trauma in normal-hearing gerbils. Here, gerbils with noise-induced hearing loss were used to investigate the effects of remote trauma on residual hearing.
Gerbils underwent high-pass (4-kHz cutoff) noise exposure to produce sloping hearing loss. After 1 month of recovery, each animal's hearing loss was determined from auditory brainstem responses and baseline intracochlear recording of the cochlear microphonic and compound action potential (CAP) obtained at the round window. Subsequently, electrode insertions were performed to produce basal trauma, whereas the acoustically generated potentials to a 1-kHz tone-burst were recorded after each step of electrode advancement. Hair cell counts were made to characterize the noise damage, and cochlear whole mounts were used to identify cochlear trauma due to the electrode.
The noise exposure paradigm produced a pattern of hair cell, auditory brainstem response, and intracochlear potential losses that closely mimicked that of electrical and acoustic stimulation patients. Trauma in the basal turn, in the 15- to 30-kHz portion of the deafened region, remote from preserved hair cells, induced a decline in intracochlear acoustic responses to the hearing preserved frequency of 1 kHz.
The results indicate that a recording algorithm based on physiological markers to low-frequency acoustic stimuli can identify cochlear trauma during implantation. Future work will focus on translating these results for use with current cochlear implant technology in humans.
在一种类似电声刺激患者的听力状况的动物模型中，由于电极插入导致的耳蜗损伤可以在低频声反应中检测到。
临床证据表明，耳蜗植入过程中的内耳蜗损伤会对残余听力产生负面影响。最近，我们证明了声诱发电位在检测正常听力沙鼠的耳蜗损伤中的有用性。在这里，使用噪声诱导听力损失的沙鼠来研究远程创伤对残余听力的影响。
沙鼠接受高通（4 kHz 截止）噪声暴露以产生斜率听力损失。在 1 个月的恢复期后，通过听觉脑干反应和圆窗处获得的耳蜗微音和复合动作电位（CAP）的耳蜗内记录来确定每个动物的听力损失。随后，进行电极插入以产生基底创伤，而在电极推进的每一步之后，记录到 1 kHz 声脉冲的声诱发电位。进行毛细胞计数以表征噪声损伤，并使用耳蜗全层切片来识别由于电极引起的耳蜗损伤。
噪声暴露范式产生的毛细胞、听觉脑干反应和耳蜗内电位损失模式与电和声刺激患者非常相似。基底转、失聪区域的 15-30 kHz 部分、远离保留毛细胞的部位的创伤，导致对保留听力频率 1 kHz 的耳蜗内声反应下降。
结果表明，基于生理标记物的低频声刺激记录算法可以识别植入过程中的耳蜗损伤。未来的工作将集中在将这些结果转化为用于人类当前的人工耳蜗技术。
