Stimulating the cochlear apex without longer electrodes

项目总结 人工耳蜗(CI)电极阵列仅部分插入耳蜗内，在大多数情况下离开 超过一半的耳蜗没有受到刺激。在正常听力耳朵中，耳蜗区不受刺激 大多数配置项代表的频率低于大约800赫兹。为更广泛的 有CI的耳蜗区具有提高性能的潜力。例如，增加顶端 覆盖已被证明可以改善言语知觉，并加速CI患者对其设备的适应。 这些好处可能是由于低频信息的表现更接近正常的耳蜗处。 此外，深度超过一圈的刺激可以提供更好的时间信息感知 以及更好的音质。然而，使用更长的电极阵列进入深尖区域有几个 劣势。首先，由于鼓阶直径随着耳蜗深度的增加而减小，因此鼓阶直径随耳蜗深度的增加而减小。 不完全插入的可能性随着电极阵列长度的增加而增加。其次，如果更深的插入是 当耳蜗管的壁变得更薄时，耳蜗管结构受损的可能性就会增加。 离电极更近一些。第三，即使是最长的电极也只能刺激约70%的耳蜗长。 为了解决这些缺点，我们开发了一种新的方法来刺激耳蜗尖 而不增加电极阵列长度。此外，我们的方法使用现有的FDA批准的 CI、语音处理器和商业配件软件，无需修改。在人工耳机CI设备中， 两个额外的耳蜗电极(ECEs)用于接地：ECE1(通常放置在颞肌下方 肌肉)和ECE2(位于植入盒上)。在新的方法中，ECE1被放置在耳蜗中 该电极阵列从耳蜗基底端插入 通过传统的耳蜗造口术。当阵列中的电极与耳蜗内的ECE1接地时 螺旋毛孔，电场被驱动到耳蜗尖，刺激局部残留的神经组织 比标准配置的电极阵列和接地电极更深。使用ECE2 因为地面提供单极刺激，这是临床标准。到目前为止，我们成功地 用这种新的手术入路植入了三名患者，并实现了新的信号处理 使用ECE1电极。当使用ECE1而不是ECE2作为接地时，所有人都报告了较低的音调。 这种新的方法提供了一个独特的机会来回答重要的科学问题和 评估一种新的临床干预措施。它提供了第一次直接刺激耳蜗的机会 人类的螺旋菌(顶端)。我们现在可以研究这种刺激是否改善了时间编码(目标1)和 扩展音调音调范围(目标2)。此外，我们还可以研究干预是否能改善临床 成果(目标3)。我们建议用这种新的方法植入15名患者，以实现这三个目标。

PROJECT SUMMARY Cochlear implant (CI) electrode arrays are only partially inserted into the cochlea, in most cases leaving more than half of the cochlea unstimulated. In the normal hearing ear, the cochlear region left unstimulated by most CIs represents frequencies below approximately 800Hz. Providing electrical stimulation to a broader region of the cochlea with a CI has the potential to enhance performance. For example, increasing apical coverage has been shown to improve speech perception and accelerate CI patients’ adaptation to their device. These benefits may be due to representation of low-frequency information closer to the normal cochlear place. Furthermore, stimulation deeper than one cochlear turn may provide better perception of temporal information and better sound quality. However, using longer electrode arrays to access deep apical regions has several disadvantages. First, because the scala tympani diameter decreases with increasing cochlear depth, the likelihood of an incomplete insertion increases with electrode array length. Second, if deeper insertion is achieved, the probability of damage to cochlear structures increases as the walls of the cochlear duct become closer to the electrode. Third, even the longest electrodes only stimulate ~70% of the cochlear length. To address these shortcomings, we developed a novel approach to stimulate the cochlear apex without increasing the electrode array length. Moreover, our approach uses existing FDA-approved CIs, speech processors, and commercial fitting software without modification. In Cochlear CI devices, two extra-cochlear electrodes (ECEs) are used for grounds: ECE1 (usually placed under the temporalis muscle) and ECE2 (located on the implant case). In the novel approach, ECE1 is placed into the cochlear helicotrema via an apical cochleostomy and the electrode array is inserted from the basal end of the cochlea through a traditional cochleostomy. When an electrode from the array is grounded to ECE1 in the cochlear helicotrema, the electric field is driven towards the cochlear apex, stimulating residual neural tissue at sites deeper than available with the standard configuration of electrode arrays and ground electrodes. Using ECE2 as the ground provides monopolar stimulation, which is the clinical standard. Thus far, we have successfully implanted three patients using this novel surgical approach and implemented novel signal processing using the ECE1 electrode. All reported a lower pitch when using ECE1 instead of ECE2 as a ground. This new approach provides a unique opportunity to answer important scientific questions and to evaluate a new clinical intervention. It provides the first opportunity to directly stimulate the cochlear helicotrema (apex) in humans. We can now study if such stimulation improves temporal coding (Aim 1) and extends the tonotopic pitch range (Aim 2). Additionally, we can study if the intervention improves clinical outcomes (Aim 3). We propose to implant 15 patients with this new approach to address the three aims.