Background

Neurostimulation is an emerging treatment option for patients resistant to pharmacotherapy and ineligible for neurosurgical intervention. Compared to intracranial stimulation placement of electrodes in the subgaleal space offers a minimally invasive option for long-term seizure monitoring for responsive systems.

New method

It was investigated, whether electrode contacts of a device being developed as a stimulation system placed in the subgaleal space are suited for recording of EEG activity for seizure detection. EEG was recorded intraoperatively in four participants participating in a clinical trial during the insertion of the device. Quantitative parameters like electrode impedance, signal amplitude ranges and amplitude spectra were determined. Epileptiform patterns in the recordings were compared to patterns occurring in scalp EEG prior to device implantation.

Results

Electrode impedances, amplitude ranges for artefact free intervals and intervals containing artefacts were determined. Spectral analysis showed typical properties of EEG recordings with high amplitude content at low frequencies and a peak in the alpha band. No major noise except at power line frequency disturbed the recordings. In two patients, typical epileptiform patterns could be identified having similar characteristics as their respective scalp EEG recordings prior to device implantation.

Comparison with existing methods

New and less invasive electrode system compared to existing solutions for responsive neurostimulation.

Conclusions

The subgaleal electrode system allows for high quality EEG recordings even in an hostile unfavorable environment like an operation theatre. For the design of a signal acquisition unit of a responsive system using subgaleal electrodes, specifications could be obtained.

中文翻译：

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用于神经刺激的帽下电极阵列允许在闭环应用中记录相关信息

背景

神经刺激是一种新兴的治疗选择，适用于对药物治疗有抵抗力且不适合神经外科干预的患者。与颅内刺激相比，在帽状膜下空间放置电极为响应系统的长期癫痫发作监测提供了一种微创选择。

新方法

研究了作为刺激系统开发的设备的电极触点是否适合记录脑电图活动以检测癫痫发作。在插入设备期间，参与临床试验的四名参与者在术中记录了 EEG。确定了诸如电极阻抗、信号幅度范围和幅度谱等定量参数。将录音中的癫痫样模式与设备植入前头皮 EEG 中出现的模式进行比较。

结果

确定了无伪影间隔和包含伪影的间隔的电极阻抗、幅度范围。频谱分析显示了 EEG 记录的典型特性，在低频下具有高振幅内容，在 alpha 波段出现峰值。除了电源线频率外，没有大的噪音干扰录音。在两名患者中，可以识别出典型的癫痫样模式，其特征与设备植入前各自的头皮 EEG 记录具有相似的特征。

与现有方法的比较

与现有的响应性神经刺激解决方案相比，新型且侵入性较小的电极系统。

结论

即使在手术室等恶劣的不利环境中，帽状下电极系统也可以进行高质量的 EEG 记录。对于使用帽状下电极的响应系统的信号采集单元的设计，可以获得规范。