Department of Speech and Hearing Science, University of Illinois at Urbana-Champaign, Champaign, Illinois, USA.
Ear Hear. 2021 Sep/Oct;42(5):1218-1227. doi: 10.1097/AUD.0000000000001006.
Currently, bilateral cochlear implants (CIs) are independently programmed in clinics using frequency allocations based on the relative location of a given electrode from the end of each electrode array. By pairing electrodes based on this method, bilateral CI recipients may have decreased sensitivity to interaural time differences (ITD) and/or interaural level differences (ILD), two cues critical for binaural tasks. There are multiple different binaural measures that can potentially be used to determine the optimal way to pair electrodes across the ears. Previous studies suggest that the optimal electrode pairing between the left and right ears may vary depending on the binaural task used. These studies, however, have only used one reference location or a single bilateral CI user. In both instances, it is difficult to determine if the results that were obtained reflect a measurement error or a systematic difference across binaural tasks. It is also difficult to determine from these studies if the differences between the three cues vary across electrode regions, which could result from differences in the availability of binaural cues across frequency regions. The purpose of this study was to determine if, after experience-dependent adaptation, there are systematic differences in the optimal pairing of electrodes at different points along the array for the optimal perception of ITD, ILD, and pitch.
Data from seven bilateral Nucleus users was collected and analyzed. Participants were tested with ITD, ILD, and pitch-matching tasks using five different reference electrodes in one ear, spaced across the array. Comparisons were conducted to determine if the optimal bilateral electrode pairs systematically differed in different regions depending on whether they were measured based on ITD sensitivity, ILD sensitivity, or pitch matching, and how those pairs differed from the pairing in the participants' clinical programs.
Results indicate that there was a significant difference in the optimal pairing depending on the cue measured, but only at the basal end of the array.
The results suggest that optimal electrode pairings differ depending on the cue measured to determine optimal pairing, at least for the basal end of the array. This also suggests that the improvements seen when using optimally paired electrodes may be tied to the particular percept being measured both to determine electrode pairing and to assess performance, at least for the basal end of the array.
目前，在诊所中，双侧人工耳蜗（CI）是通过基于每个电极阵列末端给定电极的相对位置的频率分配来独立编程的。通过基于这种方法配对电极，双侧 CI 接受者可能对耳间时间差（ITD）和/或耳间水平差（ILD）的敏感性降低，这两个线索对于双耳任务至关重要。有多种不同的双耳测量方法可用于确定在耳朵之间配对电极的最佳方式。先前的研究表明，左右耳之间的最佳电极配对可能因所使用的双耳任务而异。然而，这些研究仅使用了一个参考位置或单个双侧 CI 用户。在这两种情况下，都很难确定所获得的结果是反映测量误差还是双耳任务之间的系统差异。也很难从这些研究中确定三个线索之间的差异是否在电极区域之间有所不同，这可能是由于不同频率区域之间的双耳线索可用性不同所致。本研究的目的是确定在经历依赖于经验的适应后，在阵列的不同点上对 ITD、ILD 和音高的最佳感知，电极的最佳配对是否存在系统差异。
收集并分析了来自 7 名 Nucleus 双侧使用者的数据。参与者使用 ITD、ILD 和音高匹配任务进行测试，使用一只耳朵中的五个不同参考电极，这些电极在阵列中隔开。进行了比较，以确定最佳双侧电极对是否根据它们是基于 ITD 灵敏度、ILD 灵敏度还是音高匹配来测量，在不同区域中是否存在系统差异，以及这些电极对与参与者临床方案中的电极对有何不同。
结果表明，根据所测量的线索，最佳配对存在显著差异，但仅在阵列的基底端。
结果表明，最佳电极配对取决于用于确定最佳配对的线索而有所不同，至少在阵列的基底端是这样。这也表明，使用最佳配对电极时看到的改进可能与正在测量的特定感知有关，无论是确定电极配对还是评估性能，至少在阵列的基底端是这样。
