Satzer David, Kaye Lesley C, Ojemann Steven G, Kramer Daniel R, Thompson John A
Department of Neurosurgery, University of Colorado Anschutz Medical Campus, Aurora, CO, USA; Department of Neurosurgery, University of Chicago, Chicago, IL, USA.
Department of Neurology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA.
Brain Stimul. 2025 May-Jun;18(3):738-744. doi: 10.1016/j.brs.2025.03.022. Epub 2025 Apr 1.
Mounting evidence suggests the efficacy of neuromodulation for epilepsy is mediated by network remodeling and neural state. Epilepsy network related pathophysiology has been associated with variation in the aperiodic exponent, which describes the inverse relationship between frequency and power and has been linked to synaptic-level processes. This study sought to assess relationships between periodic and aperiodic activity, disease state, and responsive stimulation.
Chronic intracranial EEG was recorded from 13 patients undergoing responsive neurostimulation for epilepsy. Recordings containing clinician-annotated seizures, stimulation triggered by device-detected interictal epileptiform activity (IEA), and stimulation-free interictal periods were analyzed. Multidien IEA cycles were identified, and recordings were classified by cycle phase. Power spectra were parameterized into periodic and aperiodic components using an established algorithm.
The aperiodic exponent was larger during seizures and pre-stimulation intervals than stimulation-free interictal recordings, and decreased following stimulation. A rise in aperiodic exponent was observed in the 12 h preceding seizures. Larger aperiodic exponent was observed during the rising phase of multidien IEA cycles. Periodic alpha and beta power were larger during seizures, pre-stimulation intervals, and high-risk (rising and/or peak) IEA cycle phases, whereas periodic theta and gamma power exhibited variable relationships. Periodic power did not change after stimulation or in the hours before seizures for any studied frequency band.
The aperiodic exponent was positively related to instantaneous and multidien disease state severity and negatively related to therapeutic stimulation. Aperiodic activity may emerge as a practical biomarker of disease state and treatment response to guide neuromodulation for epilepsy.
越来越多的证据表明，神经调节对癫痫的疗效是由网络重塑和神经状态介导的。癫痫网络相关的病理生理学与非周期性指数的变化有关，该指数描述了频率与功率之间的反比关系，并与突触水平的过程相关。本研究旨在评估周期性和非周期性活动、疾病状态与反应性刺激之间的关系。
记录了13例接受癫痫反应性神经刺激患者的慢性颅内脑电图。分析了包含临床医生标注的癫痫发作、由设备检测到的发作间期癫痫样活动（IEA）触发的刺激以及无刺激的发作间期的记录。识别了多个IEA周期，并根据周期阶段对记录进行分类。使用既定算法将功率谱参数化为周期性和非周期性成分。
癫痫发作期间和刺激前间隔的非周期性指数大于无刺激的发作间期记录，且刺激后降低。在癫痫发作前12小时观察到非周期性指数升高。在多个IEA周期的上升阶段观察到较大的非周期性指数。癫痫发作期间、刺激前间隔以及高风险（上升和/或峰值）IEA周期阶段的周期性α和β功率较大，而周期性θ和γ功率表现出不同的关系。对于任何研究的频段，周期性功率在刺激后或癫痫发作前数小时内均未改变。
非周期性指数与瞬时和多个周期的疾病状态严重程度呈正相关，与治疗性刺激呈负相关。非周期性活动可能成为疾病状态和治疗反应的实用生物标志物，以指导癫痫的神经调节。
