Electrically evoked ABR during cochlear implantation and postoperative development of speech and hearing abilities in infants with common cavity deformity as a type of inner ear malformation

Abstract

Background: The electrically evoked auditory brainstem response (eABR) during cochlear implantation in common cavity (CC) deformity has not been clinically well studied.

Aim/Objective: To investigate the eABR wave configuration during cochlear implantation, the postoperative development of hearing, and educational settings in infants with CC deformity.

Materials and Methods: Nine infants who were congenitally deaf and found to have CC deformity and suspected cochlear nerve deficiency by temporal bone CT and MRI were studied. All of them underwent sequential and unilateral cochlear implantation and their eABRs were recorded during the surgery. The postoperative development was followed up.

Results: eABRs of all the nine infants with CC deformity showed that the mean peak of the evoked wave V (eV) was the same as that in controls at latencies but was twofold higher than that in controls at thresholds and their postoperative hearing thresholds improved markedly.

Conclusion and Significance: The brainstem auditory pathways of the infants were considered intact on the basis of the eV peak latencies in the eABRs. The postoperative development of their speech and hearing abilities and their educational settings varied, probably because of the twofold higher thresholds of their eABRs and limited number of auditory neural units.

Chinese abstract

背景：电诱发听觉脑干反应（eABR）在人工耳蜗植入于共同腔畸形（CC）中的作用尚未得到临床研究。

目的：探讨先天性耳蜗畸形患儿人工耳蜗植入过程中的eABR波形态、术后听力发育及学习环境。

材料与方法：对9例先天性耳聋, 并且经颞骨CT和MRI检查发现CC畸形和疑似耳蜗神经缺损的患儿进行研究。所有患者均接受序贯和单侧人工耳蜗植入术, 术中记录 了他们的eABR。术后进行了随访。

结果：9例CC畸形患儿的eABR显示, 诱发波V（eV）的平均峰值在潜伏期与正常对照组相同, 但在阈值处比正常对照组高2倍, 术后听力阈值明显提高。

结论及意义：根据eABR的eV峰潜伏期, 婴儿脑干听觉通路是完整的。术后言语和听力能力的发展以及教育环境有所变化, 可能是因为他们的提高了两倍的听力阈值, 以及有限的听觉神经单位数量。

Keywords:

• inner ear malformation
• common cavity
• eABR
• speech
• educational settings

Acknowledgements

We thank Ms. Kayoko Sekiguchi for her secretarial assistance. This material was presented at Collegium Bern 2019, Presentation No. 75.

Disclosure statement

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.

Additional information

Funding

This research was supported by a Grant-in-Aid for Scientific Research (KAKENHI), [No. 17K11348] and a Research Grant of National Hospital Organization Network, H30-NHO (KANKAKU)-04.