Symmetric Electrode Spanning Narrows the Excitation Patterns of Partial Tripolar Stimuli in Cochlear Implants.
Symmetric Electrode Spanning Narrows the Excitation Patterns of Partial Tripolar Stimuli in Cochlear Implants.
复制标题
对称电极跨度缩小了人工耳蜗中部分三极刺激的激励模式。
DOI：
10.1007/s10162-016-0582-8
复制
发表时间：
2016
期刊：
影响因子：
--
通讯作者：
Wu,Ching-Chih
中科院分区：
文献类型：
--
作者：
Luo,Xin;Wu,Ching-Chih
在人工耳蜗（CI）中，标准部分三极（pTP）模式通过将一部分电流返回到耳蜗内的两个相邻侧翼电极来减少电流扩散。对称电极跨越（即，通过一个电极将顶端和基底返回电极与主电极分离）已经显示出当脑内返回电流的比率固定时，增加pTP刺激的音高。为了解释pTP模式中对称跨越引起的音高增加，本研究使用电场成像（EEP）在5只CI耳中测量了主电极EL8上的标准和对称跨越pTP刺激的电位。此外，诱发复合动作电位（ECAP）的空间分布和心理物理前掩蔽（PFM）模式也被测量为两个刺激。一个给定的刺激，ECAP，和PFM模式不同的形状细节，反映了不同水平的听觉处理和不同的比率的脑内返回电流的测量方法。与标准pTP刺激相比，对称跨越的pTP刺激显着减少了归一化的pTP和PFM模式的曲线下的面积，而不移动模式的峰值和质心（都在EL8附近）。由于音高和音色感知之间的相互作用，具有对称跨度的更集中的激发模式可能导致先前报道的音高增加。由于能够减少激发的扩散，pTP模式对称跨越是一种有前途的刺激策略，可以进一步提高CI的频谱分辨率和频率选择性。
In cochlear implants (CIs), standard partial tripolar (pTP) mode reduces current spread by returning a fraction of the current to two adjacent flanking electrodes within the cochlea. Symmetric electrode spanning (i.e., separating both the apical and basal return electrodes from the main electrode by one electrode) has been shown to increase the pitch of pTP stimuli, when the ratio of intracochlear return current was fixed. To explain the pitch increase caused by symmetric spanning in pTP mode, this study measured the electrical potentials of both standard and symmetrically spanned pTP stimuli on a main electrode EL8 in five CI ears using electrical field imaging (EFI). In addition, the spatial profiles of evoked compound action potentials (ECAP) and the psychophysical forward masking (PFM) patterns were also measured for both stimuli. The EFI, ECAP, and PFM patterns of a given stimulus differed in shape details, reflecting the different levels of auditory processing and different ratios of intracochlear return current across the measurement methods. Compared to the standard pTP stimuli, the symmetrically spanned pTP stimuli significantly reduced the areas under the curves of the normalized EFI and PFM patterns, without shifting the pattern peaks and centroids (both around EL8). The more focused excitation patterns with symmetric spanning may have caused the previously reported pitch increase, due to an interaction between pitch and timbre perception. Being able to reduce the spread of excitation, pTP mode symmetric spanning is a promising stimulation strategy that may further increase spectral resolution and frequency selectivity with CIs.