van Boxel Stan C J, Vermorken Bernd L, Volpe Benjamin, Guinand Nils, Perez-Fornos Angélica, Devocht Elke M J, van de Berg Raymond
Department of Otorhinolaryngology and Head and Neck Surgery, Division of Vestibular Disorders, Maastricht University Medical Center, P. Debyelaan 25, 6229 HX, Maastricht, the Netherlands; Mental Health and Neuroscience Research Institute (MHeNs), Maastricht Universit; Universiteitssingel 40, 6229 ER, Maastricht, the Netherlands.
Department of Otorhinolaryngology and Head and Neck Surgery, Division of Vestibular Disorders, Maastricht University Medical Center, P. Debyelaan 25, 6229 HX, Maastricht, the Netherlands; Mental Health and Neuroscience Research Institute (MHeNs), Maastricht Universit; Universiteitssingel 40, 6229 ER, Maastricht, the Netherlands.
Hear Res. 2025 Aug;464:109326. doi: 10.1016/j.heares.2025.109326. Epub 2025 Jun 16.
Vestibulo-cochlear implants are a potential treatment approach for patients with loss of vestibular function. A critical aspect is the development of reliable and objective outcome measures, to assess their efficacy and optimize their performance. As in cochlear implant care and other neural prostheses, electrically evoked compound action potentials (eCAP) can be used to measure the neural response to implant stimulation. eCAPs might provide information about the presence and misalignment of the electrically evoked vestibulo-ocular reflex, and potential vestibulo-cochlear interactions. This could be valuable in intra-operative functionality assessment, as input for fitting, and to measure spread of excitation. This study aimed to explore the potential role of eCAPs in vestibulo-cochlear implant research.
eCAPs were measured in ten subjects with a vestibulo-cochlear implant. Different configurations were used, i.e., trans-canal, vestibulo-cochlear and cochleo-vestibular. The predictive value of eCAPs was evaluated for four outcomes: presence of an electrically evoked vestibulo-ocular reflex (eVOR), degree of misalignment of the eVOR, auditory perception due to vestibular stimulation, and the prevalence of vestibular activation due to cochlear stimulation.
The results demonstrated a high positive predictive value of the eCAP for the presence of an eVOR (i.e., 1.0), while the negative predictive value was low (i.e., 0.54). The presence of trans-canal eCAP did not correspond with the degree of misalignment in the eVOR. Furthermore, the predictive values for auditory perception were low (i.e., ≤0.5). eCAP recordings in the cochlea to vestibular configuration imply a high likelihood of cochlear to vestibular interaction (i.e., 67% of electrodes).
The presence of a vestibular eCAP was demonstrated to be a predictor of the presence of the eVOR. However, the low negative predictive value prevents the eCAP from providing a reliable indicator for intra-operative electrode position evaluation. eCAP measurements in vestibulo-cochlear configurations indicated that spread of excitation between the cochlea and canals is already possible at stimulation levels within the clinical fitting range of both the vestibular and cochlear electrodes. Measured eCAPs did not correspond with misalignment of the eVOR or the presence of an auditory percept as result of vestibular stimulation. Future research is needed to elucidate the full potential of vestibulo-cochlear implant eCAP measurements.
前庭蜗植入物是治疗前庭功能丧失患者的一种潜在方法。一个关键方面是开发可靠且客观的结果指标，以评估其疗效并优化其性能。与人工耳蜗护理及其他神经假体一样，电诱发复合动作电位（eCAP）可用于测量植入物刺激后的神经反应。eCAP可能提供有关电诱发前庭眼反射的存在及失调情况，以及潜在的前庭蜗相互作用的信息。这在术中功能评估、作为调试的输入以及测量兴奋扩散方面可能很有价值。本研究旨在探讨eCAP在前庭蜗植入物研究中的潜在作用。
对10名接受前庭蜗植入物的受试者测量eCAP。使用了不同的配置，即经耳道、前庭蜗和蜗前庭配置。评估了eCAP对以下四个结果的预测价值：电诱发前庭眼反射（eVOR）的存在、eVOR的失调程度、前庭刺激引起的听觉感知以及耳蜗刺激引起的前庭激活发生率。
结果表明，eCAP对eVOR存在的阳性预测值很高（即1.0），而阴性预测值很低（即0.54）。经耳道eCAP的存在与eVOR的失调程度不相关。此外，听觉感知的预测值很低（即≤0.5）。耳蜗到前庭配置的eCAP记录表明耳蜗到前庭相互作用的可能性很高（即67%的电极）。
前庭eCAP的存在被证明是eVOR存在的一个预测指标。然而，低阴性预测值使eCAP无法为术中电极位置评估提供可靠指标。前庭蜗配置中的eCAP测量表明，在前庭和耳蜗电极的临床调试范围内的刺激水平下，耳蜗和半规管之间的兴奋扩散已经是可能的。测得的eCAP与eVOR的失调或前庭刺激导致的听觉感知的存在不相关。需要进一步的研究来阐明前庭蜗植入物eCAP测量的全部潜力。
