Manzouri Farrokh, Heller Simon, Dümpelmann Matthias, Woias Peter, Schulze-Bonhage Andreas
Epilepsy Center, Faculty of Medicine, University of Freiburg Medical Center, Freiburg, Germany.
BrainLinks-BrainTools Cluster of Excellence, University of Freiburg, Freiburg, Germany.
Front Syst Neurosci. 2018 Sep 20;12:43. doi: 10.3389/fnsys.2018.00043. eCollection 2018.
The closed-loop application of electrical stimulation via chronically implanted electrodes is a novel approach to stop seizures in patients with focal-onset epilepsy. To this end, an energy efficient seizure detector that can be implemented in an implantable device is of crucial importance. In this study, we first evaluated the performance of two machine learning algorithms (Random Forest classifier and support vector machine (SVM)) by using selected time and frequency domain features with a limited need of computational resources. Performance of the algorithms was further compared to a detection strategy implemented in an existing closed loop neurostimulation device for the treatment of epilepsy. The results show a superior performance of the Random Forest classifier compared to the SVM classifier and the reference approach. Next, we implemented the feature extraction and classification process of the Random Forest classifier on a microcontroller to evaluate the energy efficiency of this seizure detector. In conclusion, the feature set in combination with Random Forest classifier is an energy efficient hardware implementation that shows an improvement of detection sensitivity and specificity compared to the presently available closed-loop intervention in epilepsy while preserving a low detection delay.
通过长期植入电极进行电刺激的闭环应用是一种治疗局灶性癫痫患者癫痫发作的新方法。为此,一种能够在可植入设备中实现的节能癫痫发作检测器至关重要。在本研究中,我们首先通过使用选定的时域和频域特征,在对计算资源需求有限的情况下,评估了两种机器学习算法(随机森林分类器和支持向量机(SVM))的性能。算法的性能进一步与现有的用于治疗癫痫的闭环神经刺激设备中实施的检测策略进行了比较。结果表明,与支持向量机分类器和参考方法相比,随机森林分类器具有更优的性能。接下来,我们在微控制器上实现了随机森林分类器的特征提取和分类过程,以评估该癫痫发作检测器的能源效率。总之,与目前可用的癫痫闭环干预相比,该特征集与随机森林分类器相结合是一种节能的硬件实现方式,在保持低检测延迟的同时,提高了检测的灵敏度和特异性。