Department of Otolaryngology, Cheng Hsin General Hospital, Taipei, Taiwan ; Faculty of Medicine, School of Medicine, National Yang-Ming University, Taipei, Taiwan.
PLoS One. 2013 Aug 26;8(8):e71929. doi: 10.1371/journal.pone.0071929. eCollection 2013.
Previous animal study revealed that post-implantation electrical detection levels significantly declined within days. The impact of cochlear implant (CI) insertion on human auditory pathway in terms of impedance and electrically evoked compound action potential (ECAP) variation within hours after surgery remains unclear, since at this time frequency mapping can only commence weeks after implantation due to factors associated with wound conditions. The study presented our experiences with regards to initial switch-on within 24 hours, and thus the findings about the milieus inside cochlea within the first few hours after cochlear implantation in terms of impedance/ECAP fluctuations. The charts of fifty-four subjects with profound hearing impairment were studied. A minimal invasive approach was used for cochlear implantation, characterized by a small skin incision (≈ 2.5 cm) and soft techniques for cochleostomy. Impedance/ECAP was measured intro-operatively and within 24 hours post-operatively. Initial mapping within 24 hours post-operatively was performed in all patients without major complications. Impedance/ECAP became significantly lower measured within 24 hours post-operatively as compared with intra-operatively (p<0.001). There were no differences between pre-operative and post-operative threshold for air-conduction hearing. A significant drop of impedance/ECAP in one day after cochlear implantation was revealed for the first time in human beings. Mechanisms could be related to the restoration of neuronal sensitivity to the electrical stimulation, and/or the interaction between the matrix enveloping the electrodes and the electrical stimulation of the initial switch-on. Less wound pain/swelling and soft techniques both contributed to the success of immediate initial mapping, which implied a stable micro-environment inside the cochlea despite electrodes insertion. Our research invites further studies to correlate initial impedance/ECAP changes with long-term hearing/speech performance.
先前的动物研究表明，在数天内，植入后电检测水平显著下降。由于与伤口状况相关的因素，在手术后数小时内，关于人工耳蜗（CI）插入对人类听觉通路的影响，包括阻抗和电诱发复合动作电位（ECAP）变化，仍不清楚。此时，由于与伤口状况相关的因素，只能在植入后数周开始进行频率映射。本研究介绍了我们在手术后 24 小时内进行初始开机的经验，以及在人工耳蜗植入后最初几小时内有关耳蜗内环境的阻抗/ECAP 波动的发现。研究了 54 名重度听力障碍患者的图表。采用微创方法进行人工耳蜗植入，其特点是皮肤切口小（约 2.5 厘米），并采用柔软的方法进行耳蜗造口术。术中及术后 24 小时内测量阻抗/ECAP。所有患者均在术后 24 小时内进行了初始映射，没有出现重大并发症。与术中相比，术后 24 小时内测量的阻抗/ECAP 明显降低（p<0.001）。气导听力的术前和术后阈值之间没有差异。首次在人类中发现，在人工耳蜗植入后一天内，阻抗/ECAP 显著下降。机制可能与神经元对电刺激的敏感性恢复有关，或者与电极周围基质与初始开机的电刺激之间的相互作用有关。伤口疼痛/肿胀减轻和采用柔软的技术都有助于立即进行初始映射的成功，这意味着尽管插入了电极，但耳蜗内的微环境仍然稳定。我们的研究邀请进一步研究将初始阻抗/ECAP 变化与长期听力/言语表现相关联。
