Smoorenburg Guido F, Willeboer Christina, van Dijk Johannes E
Department of Otorhinolaryngology, University Medical Centre, Utrecht, The Netherlands.
Audiol Neurootol. 2002 Nov-Dec;7(6):335-47. doi: 10.1159/000066154.
Adjusting the speech processor of a cochlear implant, per electrode, to the individual's response is a laborious task that may interfere with a user-friendly start of implant-mediated hearing, particularly in children. This research concerns the possibility of processor adjustment based on a profile derived from measurements of the electrically evoked compound action potential (ECAP) thresholds across the electrode array, followed by adjustment of the overall level of the profile to the hearing threshold and maximum comfortable loudness level using live voice. The results for CVC word lists show that speech perception is quite insensitive to the threshold setting of the speech processor. On average, the speech score does not decrease by more than 10% when, with the new method, the threshold setting comes out so much lower that the dynamic range has doubled. In contrast, the speech score appears to be sensitive to an increase of the maximum high-frequency stimulation settings for the basal electrodes, resulting in lower scores at these higher settings. The correlation between the overall ECAP thresholds and conventionally measured subjective thresholds is weak (r = 0.64). However, the correlation between the slopes of these threshold curves is satisfactory (r = 0.82). The correlation between the ECAP thresholds and the maximum stimulation levels is poor, both with respect to overall level and slope (r = 0.39 and 0.36, respectively). Applicability of the ECAP threshold in processor adjustment could not be demonstrated in this study. Prediction of the most critical factor in speech perception, the slope of the maximum stimulation curve, from the ECAP thresholds is poor. However, considering habituation to the initial processor setting of at least 6 months, the small decrease in the CVC scores with the new setting suggests that a more user-friendly adjustment procedure can be developed.
根据每个电极上个体的反应来调整人工耳蜗的言语处理器是一项费力的任务，这可能会干扰植入介导听力的用户友好型启动，尤其是在儿童中。本研究关注基于从电极阵列上的电诱发复合动作电位（ECAP）阈值测量得出的曲线进行处理器调整的可能性，随后使用实时语音将曲线的整体水平调整到听力阈值和最大舒适响度水平。对于CVC单词列表的结果表明，言语感知对言语处理器的阈值设置相当不敏感。平均而言，当采用新方法时阈值设置降低到动态范围翻倍的程度，言语得分下降不超过10%。相比之下，言语得分似乎对基底电极的最大高频刺激设置的增加敏感，在这些较高设置下得分较低。整体ECAP阈值与传统测量的主观阈值之间的相关性较弱（r = 0.64）。然而，这些阈值曲线斜率之间的相关性令人满意（r = 0.82）。ECAP阈值与最大刺激水平之间的相关性较差，无论是在整体水平还是斜率方面（分别为r = 0.39和0.36）。本研究未能证明ECAP阈值在处理器调整中的适用性。从ECAP阈值预测言语感知中最关键的因素——最大刺激曲线的斜率效果不佳。然而，考虑到对初始处理器设置至少6个月的适应情况，新设置下CVC得分的小幅下降表明可以开发出更用户友好的调整程序。
