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(申请人提供)：人工耳蜗是一种非常成功的神经假体，可以增强或恢复严重听力受损的人的听力。然而，不同的人工耳蜗听者的表现差异很大，特别是在嘈杂的环境中，以及对于音乐等频谱复杂的刺激。病理学和影像研究表明，螺旋神经节存活神经元的分布和它们与单个CI电极的距离是表现可变性的两个来源。这项拟议的研究的目的是开发临床上有用的程序来确定耳蜗非刺激区。由此产生的功能图可以指导产生针对患者的声音处理策略，从而提高人工耳蜗听者的听觉能力。将进行三种类型的心理、物理和电生理实验，以确定低功能人工耳蜗通道的位置。所有的实验都将使用一种新的电极配置，部分三极，来激活受限的神经元群体，类似于使用窄带刺激来评估听力受损的听者的低功能听觉死区。部分三极结构是宽单极和窄三极结构的混合，其中流向两个侧翼电极的电流比例可以调整，以改变电流在耳蜗中的扩散。在第一个实验中，当部分三极分数电流变化时，将测量整个植入阵列的检测阈值。当电流场较窄时，低功能通道将从阈值相对较高的通道中推断出来，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评估。类似于应用调谐曲线来诊断声音死区，将测量调谐曲线的宽度和尖端移位，作为识别低功能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不同部分三极电流比例得到的心理物理阈值和调谐曲线进行比较。一个显著的相关性将表明，诱发电位法是一种临床实用的技术，可以检测到低功能的通道。最终，这项研究的发现可能会导致开发一种可用于临床的针对患者的标测程序。超过6万名严重听力损失的人已经安装了人工耳蜗，以恢复一些听力能力。在拟议的研究中识别低功能人工耳蜗通道可能会增强这些患者的言语和音乐知觉。