探索序贯人工耳蜗植入中电复合动作电位潜伏期的不对称性，作为外侧橄榄耳蜗束可能效应的研究

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中文摘要

目的： 对序贯植入患者第二个人工耳蜗（CI）的电生理评估通常考虑脑干（电诱发听性脑干反应）和听觉皮层（慢反应）。为进一步理解第二次植入后的听觉电生理行为，本研究使用电复合动作电位（ECAP）探讨听神经活动。
方法： 在167例双侧植入患者中，评估了73例，并分为2组：同时手术患者（33例儿童和8例成人）和序贯手术患者（21例儿童和11例成人）。序贯手术进一步分为“短延迟”（< 4年）和“长延迟”（> 4年），考虑两次手术之间间隔的时间。每位患者均通过评估ECAP的N1波进行评价，重点关注双耳的潜伏期。
结果： 在同时植入患者和序贯性渐进性/获得性耳聋成人中，ECAP的耳间潜伏期无统计学差异。相反，在序贯性先天性耳聋儿童中，第二个植入耳的潜伏期在时间上早于第一个植入耳，但对称性在术后2年内恢复。
结论： 结果揭示，晚期序贯CI刺激在先天性耳聋儿童中于第一级神经元产生不对称的耳间活动。这种不对称是由于序贯N1波ECAP的提前，而非预期的延迟。该假设将其归因于传出系统调谐的暂时缺乏，特别是外侧橄榄耳蜗束，其在植入者中应仍具有活性。这些发现可通过实施与N1提前时间持续时间相似的刺激延迟，直至双耳处理正常化，从而增强序贯CI调图的益处。

英文摘要

OBJECTIVE: Electrophysiological evaluations of the second cochlear implant (CI) in sequentially implanted patients usually consider the brainstem with electrically evoked auditory brainstem responses and the auditory cortex with slow responses. To further understand auditory electrophysiological behaviour after the second implantation, the present study investigated auditory nerve activity using electrical compound action potential (ECAP).
METHODS: Of 167 bilaterally implanted patients, 73 were evaluated and divided into 2 groups: patients with simultaneous (33 children and 8 adults) and sequential (21 children and 11 adults) surgeries. The sequential surgeries were further grouped into "short delay" (< 4 years) and "long delay" (> 4 years), considering the time spent between procedures. Every patient was assessed by evaluating the N1 wave of ECAP, focusing on the latencies in both ears.
RESULTS: The ECAP's interaural latencies were not statistically different in simultaneous patients and sequential progressive/acquired deaf adults. In contrast, in sequential congenital deaf children, the latencies of the second implant were temporally earlier than those of the first implant, but symmetry recovered within 2 years after surgery.
CONCLUSIONS: The results revealed that late-sequential CI stimulation generates asymmetric interaural activity at the first neuron in congenitally deaf children. Such an asymmetry is due to the anticipation of the sequential N1 wave ECAP, rather than the expected delay. The hypothesis attributes it to a temporary lack of efferent system tuning, particularly the lateral olivocochlear bundle, which should still be active in implantees. These findings could enhance the benefits of sequential CI mapping by implementing a stimulation delay with a temporal duration similar to N1 anticipation until binaural processing normalises.