Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, New York, USA.
Department of Neurology, Yale University, New Haven, Connecticut, USA.
Epilepsia. 2021 Mar;62(3):742-751. doi: 10.1111/epi.16822. Epub 2021 Feb 12.
The electroencephalographic (EEG) terms "brief potentially ictal rhythmic discharges" (BIRDs) and "paroxysmal fast activity" (PFA) are considered distinct entities; however, their definitions overlap, and they may have similar clinical significance. We investigated their clinical significance and their association with seizures and the seizure onset zone (SOZ).
We retrospectively identified an adult cohort (July 2015 to March 2018) whose long-term (>12 h) EEGs in any setting reported BIRDs (>4 Hz, lasting .5-10 s) and/or PFA. Different frequency cutoffs for PFA (>13 Hz or ≥8 Hz) were tested to compare their clinical significance. Patient demographics, clinical history, and EEG features were recorded.
We identified 94 patients with BIRDs/PFA out of 3520 patients (3%); 36 were critically ill (12 with epilepsy), and 58 were noncritically ill (all with epilepsy). The frequency of BIRDs/PFA was largely dependent on EEG background: it tended to be slower (theta) in the absence of a posterior dominant rhythm or in the presence of continuous focal slowing in the same region (p = .01). Sixty-two of 94 patients (66%; 32/36 [89%] critically ill, 30/58 [52%] noncritically ill) had electrographic seizures during the recording. The scalp EEG SOZ colocalized with BIRDs/PFA in all cases. BIRDs with faster frequency (also qualifying as PFA by definition) had similar seizure risk to that of slower BIRDs (62%-71%), regardless of frequency cutoff used to define PFA. In addition, 30 of 30 (100%) patients with evolving BIRDs/PFA (which lasted a median of 6 s, range = 2-9.5 s) had electrographic seizures (>10 s), compared to 32 of 64 (50%) with nonevolving BIRDs (median = 1 s, range = .5-3.5 s; p < .01).
A high proportion of patients with BIRDs/PFA had seizures on EEG, regardless of their frequency (i.e., whether they also qualified as PFA), and their location colocalized with scalp SOZ in all cases. BIRDs appear to be a scalp EEG biomarker of uncontrolled seizure activity and a reliable localizing sign of the SOZ.
脑电图（EEG）术语“短暂潜在癫痫样节律放电”（BIRDs）和“阵发性快活动”（PFA）被认为是不同的实体；然而，它们的定义有重叠之处，并且它们可能具有相似的临床意义。我们研究了它们的临床意义及其与癫痫发作和发作起始区（SOZ）的关系。
我们回顾性确定了一个成年队列（2015 年 7 月至 2018 年 3 月），其在任何环境下的长程（>12 小时）EEG 报告 BIRDs（>4 Hz，持续时间为.5-10 s）和/或 PFA。测试了不同的 PFA 频率截止值（>13 Hz 或≥8 Hz），以比较其临床意义。记录患者的人口统计学、临床病史和 EEG 特征。
我们在 3520 名患者（3%）中发现了 94 名患有 BIRDs/PFA 的患者；36 名患者病情危急（其中 12 名患有癫痫），58 名患者病情非危急（均患有癫痫）。BIRDs/PFA 的频率在很大程度上取决于 EEG 背景：在后头部主导节律缺失或同一区域连续局灶性减速的情况下，它往往更慢（θ波）（p=0.01）。94 名患者中有 62 名（66%；36 名中的 32 名[89%]危急，58 名中的 30 名[52%]非危急）在记录期间出现了电描记图癫痫发作。头皮 EEG SOZ 在所有情况下都与 BIRDs/PFA 共定位。具有更快频率的 BIRDs（根据定义也符合 PFA）与较慢的 BIRDs 具有相似的癫痫发作风险（62%-71%），无论用于定义 PFA 的频率截止值如何。此外，30 名（100%）BIRDs/PFA 进展的患者（持续时间中位数为 6 s，范围为 2-9.5 s）发生了电描记图癫痫发作（>10 s），而 64 名中无进展 BIRDs 的患者为 32 名（50%）（中位数为 1 s，范围为.5-3.5 s；p<0.01）。
无论其频率（即是否也符合 PFA）如何，BIRDs/PFA 患者中有很大比例在 EEG 上出现癫痫发作，并且它们的位置在所有情况下都与头皮 SOZ 共定位。BIRDs 似乎是癫痫发作活动不受控制的头皮 EEG 生物标志物，也是 SOZ 的可靠定位标志。
