Electrode estimation in the acoustic region of the human Cochlea

Abstract

Background: In this study, a method to estimate number of electrodes in the acoustic region of Electric Acoustic Stimulation (EAS) subjects was proposed. Aims/Objectives: To develop and validate an anatomy-based method for EAS subjects to estimate the number of electrodes within the acoustic region.

Material and methods: The postoperative CTs of adults with various degree of hearing implanted with lateral wall electrodes with mean insertion depth of 23.9 mm (18.0–28.2 mm) and mean insertion angle of 505° (355–695°) were evaluated.

Results: The difference between the estimated and measured angle varied between −18 and 25°, with a mean of 0.9°. For the insertion angle of 230° and higher, the maximum difference was 24°. Taking this uncertainty into account, all electrodes in the acoustic region were predicted correctly.

Conclusions and significance: The method decides on non-overlapping acoustic and electric stimulation in terms of place in the cochlea. With the accuracy of 0.84 mm for the electrode arrays inserted for more than 230°, the method was sufficient to estimate the exact number of electrodes in the acoustic region of cochlear implantees. The benefit of this method may be in fitting of EAS subjects with some portion of the electrode array in the acoustic region.

Chinese abstract

背景：在本研究中, 我们提出一种估计电声刺激受试者声区电极数目的方法。

目的：开发并验证一种基于解剖学的, 用于估计EAS受试者声区内电极数量的方法。

材料与方法：对不同程度听力的成人行侧壁电极植入, 平均插入深度23.9 mm（18.0-28.2 mm）, 平均插入角505°（355-695°）。对他们的术后CT进行检测。

结果：估计角度与测量角度之差在-18°和25°之间, 平均值为0.9°。对于230°及以上的插入角, 最大差异为24°。考虑到这种不确定性, 正确预测了声区的所有电极。

结论及意义：该方法根据耳蜗的位置来决定声电刺激的非重叠性。对于插入超过230°的电极阵列, 该方法的准确度为0.84 mm, 足以估计耳蜗植入物声区的准确电极数目。该方法的优点是可以将EAS受试者拟合于声区的电极阵列的某一部分。

Keywords:

• Electric acoustic stimulation
• lateral wall electrodes
• hearing preservation
• acoustic region

Acknowledgements

The authors would like to thank Dr. Anne M. Römgens for her technical contribution and great support through this project.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

The collection of the data, CT scans and its evaluation was supported by the Polish National Science Centre, decision no. DEC-2013/09/B/ST7/04213.