Lawrence Bloomberg School of Nursing, University of Toronto, Toronto, Ontario, Canada.
Division of Neurology, The Hospital for Sick Children, Toronto, Ontario, Canada.
Seizure. 2018 May;58:55-61. doi: 10.1016/j.seizure.2018.03.026. Epub 2018 Mar 30.
Hypsarrhythmia is an electroencephalographic pattern associated with epileptic spasms and West syndrome. West syndrome is a devastating epileptic encephalopathy, originating in infancy. Hypsarrhythmia has been deemed to be the interictal brain activity, while the electrodecremental event associated with the spasms is denoted as the ictal event. Though characterized as chaotic, asynchronous and disorganized based on visual inspection of the EEG, little is known of the dynamics of hypsarrhythmia and how it impacts the developmental arrest of these infants.
As an exploratory and feasibility study, we explored the dynamics of both hypsarrhythmia and electrodecremental events with EEG phase synchronization methods, and in a convenience sample of three outpatients with epileptic spasms. As ictal events are associated with prolonged phase synchronization, we hypothesized that if hypsarrhythmia was indeed the interictal brain activity that it would have lower phase synchronization than the electrodecremental event (ictal phase).
We calculated both the phase synchronization index and the temporal variability of the index in three patients with infantile spasms. Two patients had hypsarrhythmia and electrodecremental events and one had hemi-hypsarrhythmia. We found that the hypsarrhythmia pattern was a more synchronized state than the electrodecremental event.
We have observed that the hypsarrhythmia pattern may represent a more synchronized state than the electrodecremental event in infants with epileptic spasms. However, larger studies are needed to replicate and validate these findings. Additionally, further inquiry is required to determine the impact that increased synchronization may have on developmental outcomes in infants with epileptic spasms.
高度失律是一种与癫痫痉挛和 West 综合征相关的脑电图模式。West 综合征是一种破坏性的癫痫性脑病，起源于婴儿期。高度失律被认为是发作间期的脑活动，而与痉挛相关的电极衰减事件则被表示为发作事件。尽管从脑电图的视觉检查来看，高度失律被认为是混沌、异步和无序的，但对于高度失律的动力学及其如何影响这些婴儿的发育停滞知之甚少。
作为一项探索性和可行性研究，我们使用脑电图相位同步方法探索了高度失律和电极衰减事件的动力学，并对 3 名患有癫痫痉挛的门诊患者进行了方便样本研究。由于发作事件与延长的相位同步相关，我们假设如果高度失律确实是发作间期的脑活动，那么它的相位同步性将低于电极衰减事件（发作相）。
我们计算了 3 名婴儿痉挛患者的相位同步指数和指数的时间变异性。其中 2 名患者有高度失律和电极衰减事件，1 名患者有半高度失律。我们发现高度失律模式比电极衰减事件更具同步性。
我们观察到在患有癫痫痉挛的婴儿中，高度失律模式可能比电极衰减事件代表更同步的状态。然而，需要更大的研究来复制和验证这些发现。此外，需要进一步探究增加的同步性可能对患有癫痫痉挛的婴儿的发育结果产生的影响。
