The Underlying Mechanism of Preventing Facial Nerve Stimulation by Triphasic Pulse Stimulation in Cochlear Implant Users Assessed With Objective Measure
The Underlying Mechanism of Preventing Facial Nerve Stimulation by Triphasic Pulse Stimulation in Cochlear Implant Users Assessed With Objective Measure
复制标题
DOI：
10.1097/mao.0000000000001156
复制
发表时间：
2016-10-01
影响因子：
2.1
通讯作者：
Baumann, Uwe
中科院分区：
文献类型：
--
作者：
Bahmer, Andreas;Baumann, Uwe
假设：三相脉冲刺激防止面神经刺激(FNS)，因为与双相脉冲刺激相比，面神经刺激具有不同的肌电输入输出功能。背景：有时在人工耳蜗者中观察到面神经刺激是电刺激听神经的不良副作用。目前人工耳蜗术中常用的刺激方式是双相脉冲模式。预防某些电极激活引起的不适FNS的两种常见临床治疗方法是延长其脉冲相位持续时间或简单地使其失活。不幸的是，在一些患者中，这些方法不能提供足够的FNS预防。在这些患者中，三相脉冲可以预防FNS。其机制尚不清楚。方法：采用面神经支配的肌肉(口轮匝肌和眼肌)的肌电记录，定量评价其对FNS的影响。对4例重度FNS患者的三相和双相拟合图进行了比较。在此基础上，建立了三相脉冲作用的模型。结果：通过安装OPUS 2语音处理器设备提供了三相刺激。对于三名患者，肌电记录成功取决于刺激水平，直到不舒服和无法忍受的FNS刺激作为上界。获得的肌电记录显示出很高的个体变异性。然而，两相和三相脉冲刺激的输入-输出函数之间的差异在视觉上是明显的。与标准的双相刺激相比，三相脉冲需要更高的刺激水平才能产生等量的FN，这一点从EMG的幅度中可以反映出来。此外，我们还假设与三相脉冲刺激相比，双相脉冲刺激的输入输出函数的斜率更大。结论：三相脉冲刺激由于肌电输入输出函数的梯度比两相脉冲刺激的小，从而防止了FNS的发生。其潜在的机制可以通过电场时空传播的差异来模拟。
Hypothesis:Triphasic pulse stimulation prevents from facial nerve stimulation (FNS) because of a different electromyographic input-output function compared with biphasic pulse stimulation.Background:FNS is sometimes observed in cochlear implant users as an unwanted side effect of electrical stimulation of the auditory nerve. The common stimulation applied in current cochlear implant consists of biphasic pulse patterns. Two common clinical remedies to prevent unpleasant FNS caused by activation of certain electrodes are to expand their pulse phase duration or simply deactivate them. Unfortunately, in some patients these methods do not provide sufficient FNS prevention. In these patients triphasic pulse can prevent from FNS. The underlying mechanism is yet unclear.Methods:Electromyographic (EMG) recordings of muscles innervated by the facial nerve (musculi orbicularis ori and oculi) were applied to quantitatively assess the effects on FNS. Triphasic and biphasic fitting maps were compared in four subjects with severe FNS. Based on the recordings, a model is presented which intends to explain the beneficial effects of triphasic pulse application.Results:Triphasic stimulation provided by fitting of an OPUS 2 speech processor device. For three patients, EMG was successfully recorded depending on stimulation level up to uncomfortable and intolerable FNS stimulation as upper boarder. The obtained EMG recordings demonstrated high individual variability. However, a difference between the input-output function for biphasic and triphasic pulse stimulation was visually observable. Compared with standard biphasic stimulation, triphasic pulses require higher stimulation levels to elicit an equal amount of FNS, as reflected by EMG amplitudes. In addition, we assume a steeper slope of the input-output function for biphasic pulse stimulation compared with triphasic pulse stimulation.Conclusion:Triphasic pulse stimulation prevents from FNS because of a smaller gradient of EMG input-output function compared with biphasic pulse stimulation. The underlying mechanism can be modeled by differences in spatiotemporal spread of the electrical field.