Hamzavi Jafar, Arnoldner Christoph
Department of Otorhinolaryngology, Medical University of Vienna, Vienna, Austria.
Acta Otolaryngol. 2006 Dec;126(11):1182-7. doi: 10.1080/00016480600672683.
Deeply inserted electrodes offer the possibility that apical stimulation may improve speech performances. Therefore, deep insertion is reasonable and should be performed in patients with profound or total hearing loss.
To evaluate the importance of insertion depth beyond 25 mm in a group of cochlear implant patients with deeply inserted electrodes up to 32 mm.
In the first part of the study patients were asked to perform a pitch estimation for channels across the whole length of the electrode array. We evaluated whether pitch discrimination was possible along the whole cochlea and especially in its apical part. Then, the audiological performances of 10 patients were tested in 5 conditions, in which we artificially varied the insertion depth in each patient by activating and deactivating channels. The patients were tested immediately in the new condition to avoid adaptation.
The results showed that activating the electrodes in the uppermost region of the cochlea improves speech perception significantly. Furthermore it could be demonstrated that the pitch perceived in the cochlea with electrical stimulation decreases with increasing insertion depth along the whole length of deeply inserted electrode arrays.
深度插入电极使得顶端刺激有可能改善言语表现。因此，深度插入是合理的，应在极重度或全聋患者中进行。
在一组电极深度插入达32毫米的人工耳蜗植入患者中，评估插入深度超过25毫米的重要性。
在研究的第一部分，要求患者对电极阵列全长的各个通道进行音调估计。我们评估了沿整个耳蜗，尤其是其顶端部分是否能够进行音调辨别。然后，在5种条件下测试了10名患者的听力学表现，在每种条件下，我们通过激活和停用通道人为改变每位患者的插入深度。为避免适应性问题，患者在新条件下立即接受测试。
结果表明，激活耳蜗最上部区域的电极可显著改善言语感知。此外，可以证明，在深度插入电极阵列的整个长度上，随着插入深度增加，电刺激时耳蜗中感知到的音调会降低。
