Probing the cochlea with partial tripolar stimulation in cochlear implantees

通过部分三极刺激探查人工耳蜗植入者的耳蜗

• 批准号: 7457468
• 负责人: JULIE G Arenberg
• 金额: $ 15.32万
• 依托单位: UNIVERSITY OF WASHINGTON
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-06-01 至 2011-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7457468
• 关键词: Acoustic Nerve; Acoustics; Auditory; Brain Stem; Clinic; Cochlea; Cochlear Implants; Complex; Detection; Development; Diagnosis; Electrodes; Environment; Evoked Potentials; Growth; Hearing; Hybrids; Image; Implant; Individual; Inner Hair Cells; Lead; Location; Loudness; Maps; Masks; Measurement; Measures; Methods; Music; Neurons; Numbers; Pathology; Patients; Perception; Performance; Pilot Projects; Placement; Population; Procedures; Process; Production; Psychophysiology; Range; Research; Resolution; Shapes; Source; Speech; Stimulus; Techniques; Testing; Width; base; hearing impairment; improved; interest; neural prosthesis; novel; research study; response; sound; speech processing; spiral ganglion

DESCRIPTION (provided by applicant): Cochlear implants are highly successful neural prostheses that enhance or restore hearing to the severely hearing impaired. However, performance varies considerably among cochlear implant listeners, particularly in noisy environments and for spectrally complex stimuli like music. Pathology and imaging studies suggest that two sources of performance variability are the distribution of surviving spiral ganglion neurons and their distance from individual CI electrodes. The objective of the proposed study is to develop clinically useful procedures to determine non-stimulable regions of the cochlea. The resulting functional maps could guide the production of patient-specific sound processing strategies, leading to improvements in the auditory ability of cochlear implant listeners. Three types of psychophysical and electrophysiological experiments will be conducted to identify the location of low functioning cochlear implant channels. All experiments will use a novel electrode configuration, partial tripolar, to activate restricted populations of neurons, analogous to the use of narrowband stimuli for assessing low functioning acoustic dead regions in hearing impaired listeners. The partial tripolar configuration is a hybrid between the broad monopolar and narrow tripolar configurations, in which the fraction of current that flows to two flanking electrodes can be adjusted to change the spread of current in the cochlea. In the first experiment, detection thresholds will be measured across the implant array as the partial tripolar fractional current varies. Low functioning channels will be inferred from channels with relatively high thresholds when the current field is narrow and the change in threshold with fractional current will provide information about the spatial extent of the functional deficit. In the second experiment, psychophysical tuning curves will be obtained using a forward masking procedure to provide a more detailed assessment of cochlear activation. Similar to the application of tuning curves to diagnose acoustic dead regions, the widths and tip shifts of the tuning curves will be measured as a way to identify low functioning cochlear implant channels. In the third experiment, evoked potentials will be recorded. Evoked potential thresholds and amplitude growth functions will be directly compared to psychophysical thresholds and tuning curves obtained with different partial tripolar current fractions. A significant correlation will suggest that the evoked potential procedure, which is a clinically practical technique, can detect low functioning channels. Ultimately, the findings of this study may lead to the development of a patient-specific mapping procedure that can be used clinically. Over 60,000 people with severe hearing loss have been fitted with cochlear implants to restore some auditory capabilities. Identifying low functioning cochlear implant channels in the proposed study could lead to the enhancement of speech and music perception in these patients.

描述（由申请人提供）：人工耳蜗是非常成功的神经假体，可以增强或恢复严重听力受损者的听力。然而，人工耳蜗听者的性能差异很大，特别是在嘈杂的环境中和音乐等频谱复杂的刺激下。病理学和影像学研究表明，性能变异的两个来源是存活螺旋神经节神经元的分布及其与单个 CI 电极的距离。拟议研究的目的是开发临床上有用的程序来确定耳蜗的不可刺激区域。由此产生的功能图可以指导制定针对患者的声音处理策略，从而提高人工耳蜗聆听者的听觉能力。将进行三种类型的心理物理学和电生理学实验，以确定功能低下的人工耳蜗通道的位置。所有实验都将使用一种新颖的电极配置（部分三极）来激活有限的神经元群，类似于使用窄带刺激来评估听力受损听众的低功能声死区。部分三极配置是宽单极配置和窄三极配置之间的混合体，其中流向两个侧翼电极的电流部分可以调整以改变电流在耳蜗中的分布。在第一个实验中，随着部分三极分数电流的变化，将测量整个植入体阵列的检测阈值。当电流场较窄时，将从具有相对较高阈值的通道推断出功能低下的通道，并且阈值随分数电流的变化将提供有关功能缺陷的空间范围的信息。在第二个实验中，将使用前向掩蔽程序获得心理物理调谐曲线，以提供对耳蜗激活的更详细的评估。与应用调谐曲线诊断声死区类似，将测量调谐曲线的宽度和尖端偏移，作为识别功能低下的人工耳蜗通道的一种方法。在第三个实验中，将记录诱发电位。诱发电位阈值和幅度增长函数将直接与心理物理阈值和用不同的部分三极电流分数获得的调谐曲线进行比较。显着的相关性表明诱发电位程序是一种临床实用技术，可以检测低功能通道。最终，这项研究的结果可能会导致开发出可用于临床的患者特异性标测程序。超过 60,000 名严重听力损失的人已安装人工耳蜗以恢复部分听觉能力。在拟议的研究中识别功能低下的人工耳蜗通道可能会增强这些患者的言语和音乐感知。