Abstract：
BACKGROUND: Accurate identification of abnormal electroencephalographic (EEG) activity is pivotal for diagnosing and treating epilepsy. Recent studies indicate that decomposing brain activity into periodic (oscillatory) and aperiodic (trend across all frequencies) components can illuminate the drivers of spectral activity changes.
METHODS: We analysed intracranial EEG (iEEG) data from 234 subjects, creating a normative map. This map was compared to a cohort of 63 patients with refractory focal epilepsy under consideration for neurosurgery. The normative map was computed using three approaches: (i) relative complete band power, (ii) relative band power with the aperiodic component removed, and (iii) the aperiodic exponent. Abnormalities were calculated for each approach in the patient cohort. We evaluated the spatial profiles, assessed their ability to localize abnormalities, and replicated the findings using magnetoencephalography (MEG).
RESULTS: Normative maps of relative complete band power and relative periodic band power exhibited similar spatial profiles, while the aperiodic normative map revealed higher exponent values in the temporal lobe. Abnormalities estimated through complete band power effectively distinguished between good and bad outcome patients. Combining periodic and aperiodic abnormalities enhanced performance, like the complete band power approach.
CONCLUSIONS: Sparing cerebral tissue with abnormalities in both periodic and aperiodic activity may result in poor surgical outcomes. Both periodic and aperiodic components do not carry sufficient information in isolation. The relative complete band power solution proved to be the most reliable method for this purpose. Future studies could investigate how cerebral location or pathology influences periodic or aperiodic abnormalities.
METHODS: We analysed intracranial EEG (iEEG) data from 234 subjects, creating a normative map. This map was compared to a cohort of 63 patients with refractory focal epilepsy under consideration for neurosurgery. The normative map was computed using three approaches: (i) relative complete band power, (ii) relative band power with the aperiodic component removed, and (iii) the aperiodic exponent. Abnormalities were calculated for each approach in the patient cohort. We evaluated the spatial profiles, assessed their ability to localize abnormalities, and replicated the findings using magnetoencephalography (MEG).
RESULTS: Normative maps of relative complete band power and relative periodic band power exhibited similar spatial profiles, while the aperiodic normative map revealed higher exponent values in the temporal lobe. Abnormalities estimated through complete band power effectively distinguished between good and bad outcome patients. Combining periodic and aperiodic abnormalities enhanced performance, like the complete band power approach.
CONCLUSIONS: Sparing cerebral tissue with abnormalities in both periodic and aperiodic activity may result in poor surgical outcomes. Both periodic and aperiodic components do not carry sufficient information in isolation. The relative complete band power solution proved to be the most reliable method for this purpose. Future studies could investigate how cerebral location or pathology influences periodic or aperiodic abnormalities.
摘要：
背景：准确识别异常脑电图（EEG）活动对于诊断和治疗癫痫至关重要。最近的研究表明，将大脑活动分解为周期性（振荡）和非周期性（跨所有频率的趋势）成分可以阐明光谱活动变化的驱动因素。
方法：我们分析了234名受试者的颅内脑电图（iEEG）数据，创建一个规范的地图。将该图与考虑进行神经外科手术的63例难治性局灶性癫痫患者的队列进行了比较。使用三种方法计算规范图：(I)相对完整频带功率，(ii)去除非周期性分量的相对频带功率，和(iii)非周期性指数。在患者队列中计算每种方法的异常。我们评估了空间剖面，评估了他们定位异常的能力，并使用脑磁图（MEG）复制了这些发现。
结果：相对完整频带功率和相对周期频带功率的规范图表现出相似的空间分布，而非周期性的规范图显示颞叶的指数值较高。通过完全频带功率估计的异常可有效区分好结果和坏结果患者。结合周期性和非周期性异常增强性能，就像完整的波段功率方法。
结论：保留周期性和非周期性活动异常的脑组织可能导致不良的手术结果。周期性和非周期性分量都不能单独携带足够的信息。相对完整的频带功率解决方案被证明是用于此目的的最可靠的方法。未来的研究可以研究大脑位置或病理如何影响周期性或非周期性异常。
方法：我们分析了234名受试者的颅内脑电图（iEEG）数据，创建一个规范的地图。将该图与考虑进行神经外科手术的63例难治性局灶性癫痫患者的队列进行了比较。使用三种方法计算规范图：(I)相对完整频带功率，(ii)去除非周期性分量的相对频带功率，和(iii)非周期性指数。在患者队列中计算每种方法的异常。我们评估了空间剖面，评估了他们定位异常的能力，并使用脑磁图（MEG）复制了这些发现。
结果：相对完整频带功率和相对周期频带功率的规范图表现出相似的空间分布，而非周期性的规范图显示颞叶的指数值较高。通过完全频带功率估计的异常可有效区分好结果和坏结果患者。结合周期性和非周期性异常增强性能，就像完整的波段功率方法。
结论：保留周期性和非周期性活动异常的脑组织可能导致不良的手术结果。周期性和非周期性分量都不能单独携带足够的信息。相对完整的频带功率解决方案被证明是用于此目的的最可靠的方法。未来的研究可以研究大脑位置或病理如何影响周期性或非周期性异常。
