The electrode-neural interface in auditory brainstem implants

项目摘要 听觉脑干植入物（ABI）是耳蜗异常或 听神经ABI绕过听觉神经，直接刺激中枢听觉通路， 通过手术将电极置于耳蜗核上。目前的ABI设备使用相同的编码策略 人工耳蜗（CI）将声音编码为电刺激。然而，尽管外部 硬件、信号处理和由ABI和CI电极递送的刺激模式，这两个 不同的设备会产生不同的结果。只有一小部分的ABI患者可以理解使用 他们的设备，而CI患者通常可以单独使用他们的设备进行口头交流。的 这些不同结果的机制是难以捉摸的，但可能与电极的差异有关， 两个设备之间的神经接口特性。耳蜗核是ABI刺激的部位， 比听觉神经复杂得多，由不同类型的神经元组成。大多数耳蜗 核神经类型具有与听神经不同的生物物理特性。目的一是研究电极- ABI患者的神经界面特征及其与感知结果的关系。我们将研究 电极-神经接口，通过使用电刺激获得电诱发复合动作电位（ECAP）。 植入装置的电压记录能力。我们将使用ECAP来评估神经细胞的形态学， 反应以及神经恢复和神经反应的适应。我们还将评估神经 不同电极之间的相互作用。我们将评估电极-神经界面之间的关联 和行为表现，并评估这种关联在ABI和CI患者之间的差异。目标二是 评估电极-神经接口措施是否可以指导消除功能不良 电极，以改善ABI患者的结果。我们将比较之前获得的言语感知结果， 并且在从编码策略中消除功能差的电极之后。言语感知结局 当受试者有机会适应一个新的操作时， 月这项研究将提供关键的理解听觉处理之间的差异ABI 和CI用户，这可能与耳蜗和耳蜗之间的电极-神经界面的差异有关。 耳蜗核

PROJECT SUMMARY Auditory brainstem implants (ABI) are the only therapeutic option for deaf patients with abnormal cochlea or auditory nerve. ABIs bypass the auditory nerve and directly stimulate the central auditory pathways using electrodes surgically placed on the cochlear nucleus. Current ABI devices use the same coding strategies as cochlear implants (CI) to encode sound into electrical stimulation. However, despite identical external hardware, signal processing, and stimulation patterns being delivered by ABI and CI electrodes, the two devices have very different outcomes. Only a small percentage of ABI patients can understand speech using their device, whereas CI patients can generally communicate verbally using their device alone. The mechanisms for these disparate outcomes are elusive, but may be related to the differences in electrode- neural interface characteristics between the two devices. The cochlear nucleus, the site of ABI stimulation, is much more complex than the auditory nerve and consists of diverse neuron types. The majority of cochlear nucleus neural types have different biophysical properties than the auditory nerve. Aim 1 is to study electrode- neural interface characteristics in ABI patients and their relation to perceptual outcomes. We will study electrode-neural interface by obtaining electrically-evoked compound action potentials (ECAPs) using the voltage recording capability of the implant device. We will use ECAP to assess the morphology of neural responses as well as neural recovery and adaptation of neural responses. We will also assess neural interactions between different electrodes. We will evaluate the association between electrode-neural interface and behavioral performance, and assess how this association differs between ABI and CI patients. Aim 2 is to evaluate whether the electrode-neural interface measures can guide elimination of poorly functioning electrodes to improve ABI patient outcomes. We will compare speech perception outcomes obtained before and after eliminating the poorly functioning electrodes from the coding strategy. Speech perception outcomes with each new manipulation will be measured when the subjects have had the opportunity to adapt to it for one month. This study will provide critical understanding regarding auditory processing differences between ABI and CI users, which may be related to differences in electrode-neural interface between the cochlea and the cochlear nucleus.