Frequency-to-Place Mismatch: Characterizing Variability and the Influence on Speech Perception Outcomes in Cochlear Implant Recipients.
Frequency-to-Place Mismatch: Characterizing Variability and the Influence on Speech Perception Outcomes in Cochlear Implant Recipients.
复制标题
DOI：
10.1097/aud.0000000000000864
复制
发表时间：
2020
期刊：
影响因子：
3.7
通讯作者：
O'Connell BP
中科院分区：
文献类型：
--
作者：
Canfarotta MW;Dillon MT;Buss E;Pillsbury HC;Brown KD;O'Connell BP
人工耳蜗（CI）电极阵列的空间位置影响提供给受者的光谱线索。耳蜗大小和阵列长度的差异导致阵列类型之间和内部的角插入深度（AID）有很大的差异。对于单独使用ci的用户，AID的可变性导致默认电频率滤波器与耳蜗刺激位置之间不同程度的频率-位置不匹配。对于电声刺激（EAS）的使用者，默认的电频率滤波器也会随着植入耳中残余声学听力的功能而变化。本报告旨在：1)调查与侧壁阵列相关的AID变异性，2)确定使用默认频率滤波器的单独ci和EAS用户随后的频率对位置不匹配，以及3)检查单独ci用户的早期语音感知与电极位置的两个方面之间的关系：频率对位置不匹配和相邻触点之间的角分离，这是与周边频谱选择性相关的度量。采用MED-EL Flex24 （24 mm）、Flex28 （28 mm）和FlexSOFT/Standard （31.5 mm）阵列的101名成年CI受者（111耳）术后接受计算机断层扫描以确定AID。随后对AID、预测的螺旋神经节位置频率以及单独使用ci （n = 84）和EAS用户（n = 27）的默认频率滤波器进行了比较。对于完全插入的单独ci用户，使用符合默认频率滤波器的地图（n = 48）收听，频率-位置不匹配在1500 Hz被量化，相邻触点之间的角分离在1-2 kHz区域被确定。使用多元线性回归来检验频率-地点不匹配和接触角分离在激活后6个月对辅音-核-辅音（CNC）评分的影响。对于完全插入的CI受者（n = 106, 95.5%）， Flex24 （n = 11）、Flex28 （n = 48）和FlexSOFT/ standard （n = 47）最尖端接触的AID（平均值±标准差）分别为428°±34.3°、558°±65.4°。对于单独使用ci的用户，默认频率滤波器与深插入侧壁阵列的螺旋神经节图紧密对齐。对于EAS用户，默认频率滤波器产生一系列不匹配；绝对偏差≤6个半音的病例仅占37%。浅层插入和最小或没有残余听力的参与者经历了最大的不匹配。对于单独使用ci的用户，在设备使用的最初6个月期间，较小的频率-位置不匹配和较大的触点角度分离与较好的CNC分数相关。在单独使用ci和使用默认频率滤波器的EAS用户之间，甚至在植入相同阵列的个体之间，频率对位置的不匹配存在显著差异。当使用默认频率滤波器时，对于单独使用ci和EAS的用户，可以使用更长的侧壁阵列和满足与残余听力相关的边缘频率的插入深度来最大限度地减少不匹配。较小程度的频率-位置不匹配和由于更宽间隔接触而减少的外围掩蔽可能独立支持单独使用ci的用户使用更长的侧壁阵列时更好的语音感知。
The spatial position of a cochlear implant (CI) electrode array affects the spectral cues provided to the recipient. Differences in cochlear size and array length lead to substantial variability in angular insertion depth (AID) across and within array types. For CI-alone users, the variability in AID results in varying degrees of frequency-to-place mismatch between the default electric frequency filters and cochlear place of stimulation. For electric-acoustic stimulation (EAS) users, default electric frequency filters also vary as a function of residual acoustic hearing in the implanted ear. The present report aimed to: 1) investigate variability in AID associated with lateral wall arrays, 2) determine the subsequent frequency-to-place mismatch for CI-alone and EAS users mapped with default frequency filters, and 3) examine the relationship between early speech perception for CI-alone users and two aspects of electrode position: frequency-to-place mismatch and angular separation between neighboring contacts, a metric associated with spectral selectivity at the periphery. One hundred one adult CI recipients (111 ears) with MED-EL Flex24 (24 mm), Flex28 (28 mm), and FlexSOFT/Standard (31.5 mm) arrays underwent postoperative computed tomography to determine AID. A subsequent comparison was made between AID, predicted spiral ganglion place frequencies, and the default frequency filters for CI-alone (n = 84) and EAS users (n = 27). For CI-alone users with complete insertions who listened with maps fit with the default frequency filters (n = 48), frequency-to-place mismatch was quantified at 1500 Hz and angular separation between neighboring contacts was determined for electrodes in the 1-2 kHz region. Multiple linear regression was used to examine how frequency-to-place mismatch and angular separation of contacts influence consonant-nucleus-consonant (CNC) scores through 6 months post-activation. For CI recipients with complete insertions (n = 106, 95.5%), the AID (mean ± standard deviation) of the most apical contact was 428° ± 34.3° for Flex24 (n = 11), 558° ± 65.4° for Flex28 (n = 48), and 636° ± 42.9° for FlexSOFT/Standard (n = 47) arrays. For CI-alone users, default frequency filters aligned closely with the spiral ganglion map for deeply inserted lateral wall arrays. For EAS users, default frequency filters produced a range of mismatches; absolute deviations of ≤ 6 semitones occurred in only 37% of cases. Participants with shallow insertions and minimal or no residual hearing experienced the greatest mismatch. For CI-alone users, both smaller frequency-to-place mismatch and greater angular separation between contacts were associated with better CNC scores during the initial 6 months of device use. There is significant variability in frequency-to-place mismatch among CI-alone and EAS users with default frequency filters, even between individuals implanted with the same array. When using default frequency filters, mismatch can be minimized with longer lateral wall arrays and insertion depths that meet the edge frequency associated with residual hearing for CI-alone and EAS users, respectively. Smaller degrees of frequency-to-place mismatch and decreased peripheral masking due to more widely spaced contacts may independently support better speech perception with longer lateral wall arrays in CI-alone users.