Two types of ictal phase-amplitude couplings in epilepsy patients revealed by spectral harmonicity of intracerebral EEG recordings

ObjectiveSpectral harmonicity of the ictal activity was analyzed regarding two clinically relevant aspects, (1) as a confounding factor producing ‘spurious’ phase-amplitude couplings (PAC) which may lead to wrong conclusions about the underlying ictal mechanisms, and (2) its role in how good PAC is in correspondence to the seizure onset zone (SOZ) classification performed by the epileptologists.MethodsPAC patterns observed in intracerebral electroencephalography (iEEG) recordings were retrospectively studied during seizures of seven patients with pharmacoresistant focal epilepsy. The time locked index (TLI) measure was introduced to quantify the degree of harmonicity between frequency bands associated to the emergence of PAC during epileptic seizures.Results(1) Harmonic and non harmonic PAC patterns coexist during the seizure dynamics in iEEG recordings with macroelectrodes. (2) Harmonic PAC patterns are an emergent property of the periodic non sinusoidal waveform constituting the epileptiform activity. (3) The TLI metric allows to distinguish the non harmonic PAC pattern, which has been previously associated with the ictal core through the paroxysmal depolarizing shifts mechanism of seizure propagation.ConclusionsOur results suggest that the spectral harmonicity of the ictal activity plays a relevant role in the visual analysis of the iEEG recordings performed by the epileptologists to define the SOZ, and that it should be considered for the proper interpretation of ictal mechanisms.SignificanceThe proposed harmonicity analysis can be used to improve the delineation of the SOZ by reliably identifying non harmonic PAC patterns emerging from fully recruited cortical and subcortical areas.     

立体脑电图引导的射频热凝术治疗儿童药物难治性癫痫的疗效(附71例报告)

目的探讨立体脑电图(SEEG)引导的射频热凝术(RF-TC)治疗儿童药物难治性癫痫的疗效和安全性。方法回顾性分析首都医科大学附属北京儿童医院癫痫中心2017年1月至2018年12月收治的71例药物难治性癫痫患儿的临床资料。发作类型为局灶性发作伴或不伴泛化62例,局灶性发作合并癫痫性痉挛6例,局灶性发作合并肌阵挛发作2例,单纯癫痫性痉挛1例。影像学表现为皮质发育畸形27例,海马硬化9例,发育性或低级别肿瘤8例,脑软化灶5例,合并2种类型病变5例,头颅MRI阴性17例。所有患儿均接受SEEG引导的RF-TC治疗。通过门诊复诊及电话随访评估患儿的癫痫发作情况,并采用单因素分析法探讨手术疗效的影响因素。结果71例患儿植入颅内电极5~14根/例。8例患儿行RF-TC后出现一过性神经功能损伤。69例随访(1.2±0.5)年(0.5~2.5年),2例失随访。末次随访时,45例(65.2%)无发作,24例仍有癫痫发作,其中18例(26.1%)发作减少>50%;术后随访时间>1年的42例患儿中,25例(59.5%)无发作。2例脑室旁结节状灰质异位患儿发作均控制1年以上,局灶皮质发育不良患儿的术后6个月的无发作率为85.7%(18/21)。单因素分析结果显示,手术疗效与电极植入目的(方案)有关(P=0.007),而与手术年龄、病程、癫痫发作类型、MRI阴性无关(均P>0.05)。结论对于儿童药物难治性癫痫,SEEG引导的RF-TC是一种安全、有效的治疗手段,其适用于体积小或深在的病灶,亦可探索MRI阴性的癫痫网络,为多发病灶、累及功能区者提供了手术机会,并能辅助切除性手术制定计划、评估疗效。     

Easy anchoring and smaller skin incision procedure for neuronavigation-based frameless stereoelectroencephalography

Epilepsy surgery uses both depth electrodes (DEs) and subdural electrodes (SE). DEs have mainly been developed and used in Europe. As we are able to use the DEs safely due to the current advanced level of technology, use of DEs has been increasing rapidly over the last decade. Unlike placement of SEs, which simply requires craniotomy, DE placement generally requires stereotactic techniques such as frame-based stereotactic or robotic arm-based methods. However, such methods are not always available at every epilepsy center. We therefore invented guide pipes for accurate DE placement. With this guide pipe and neuronavigation-based (NB) DE placement system, we are able to place DEs accurately. However, the disadvantages of our original procedure were a relatively large skin incision and the difficulty in anchoring DEs. The purpose of this technical note is to introduce a method to perform NB DE placement with a smaller skin incision and simple anchoring procedure. As we could make the skin incision smaller and achieved easier anchoring of DEs using a titanium plate, we hope this procedure will help facilities to perform DE placement with neuronavigation systems.     

立体脑电图引导射频热凝毁损治疗脑室旁结节状灰质异位相关癫痫

目的探讨立体脑电图(SEEG)引导下的射频热凝毁损技术在治疗脑室旁结节状灰质异位相关癫痫中的作用。方法回顾性分析2015年3月至2017年5月北京丰台医院神经外科收治的5例脑室旁结节状灰质异位相关癫痫患者的临床资料。所有患者均根据症状学、头皮脑电图表现及影像学检查结果设计SEEG电极的植入方案,并行视频脑电监测,根据SEEG发作间期和发作期放电情况明确致痫灶的分布,根据其结果采用SEEG电极行射频热凝毁损术。术后通过门诊或电话进行随访,采用Engel分级进行预后评估。结果5例患者共植入23根电极,植入后未见明显并发症。随访时间为9~27个月,其中4例癫痫发作消失(Engel分级Ⅰ级),1例毁损术后发作频率无明显改善(Engel分级Ⅳ级)。所有患者在射频热凝毁损术中、术后均未出现明显不良反应。结论立体定向脑电图(SEEG)引导下的射频热凝毁损技术对治疗脑室旁结节状灰质异位相关癫痫具有重要的临床应用价值。     

基于癫痫患者皮质-皮质诱发电位的双侧岛叶功能连接研究(附四例报告)

目的通过立体脑电图电极皮质电刺激的方法探讨岛叶或岛叶相关药物难治性癫痫患者双侧岛叶之间的功能连接情况。方法回顾性分析2014年1月至2016年8月清华大学玉泉医院癫痫中心收治的4例岛叶或岛叶相关药物难治性癫痫患者的临床资料。4例患者均于双侧岛叶植入立体脑电图电极进行皮质电刺激,通过视觉分析和非参数检验确定每个触点有无诱发电位响应。采用刺激一侧的对侧岛叶的电极记录诱发电位响应,明确刺激响应率及解剖分布情况。结果4例患者共植入28根SEEG电极(98个触点),其中植入左侧岛叶12根电极(47个触点)。4例患者的双侧岛叶之间有皮质-皮质诱发电位(CCEP)响应。刺激一侧岛叶时,对侧岛叶CCEP的响应率为39.8%,峰潜伏期为15.5~196.0ms。此外,在双侧岛叶等位脑回间存在双向CCEP联系。结论岛叶或岛叶相关的难治性癫痫患者的双侧岛叶之间存在双向功能连接,特别是病毒性脑炎后癫痫患者,其双侧岛叶之间的连接更为广泛。但这一结果尚需更多病例来进一步证实。     

影像导航下立体定向脑电监测在额叶癫痫中的应用…

目的 探讨影像导航引导下颅内立体脑电图监测在额叶癫痫外科治疗中的作用。方法 选取2014年1月至2016年3月35例定位定侧困难的额叶癫痫,采用美敦力S7导航系统融合MRI影像,根据脑网络在导航下置入电极,术后监测脑电图定位癫痫病灶,手术切除致痫灶。结果 35例均按计划成功置入深部电极,其中单侧12例,双侧23例,均监测到3~20次临床惯常发作。1例定位困难,未手术治疗;其余34例根据脑电图结果行致痫灶切除。置入电极后1例发生硬膜外血肿,量约20 ml,癫痫病灶切除时一并清除;癫痫病灶切除术后1例早期出现单瘫,1例出现运动性失语,经治疗后恢复。34例手术病人术后随访1~3年,Engel分级Ⅰ级24例（70.5%）,Ⅱ级5例（14.7%）,Ⅲ级4例（11.7%）,Ⅳ级1例（2.9%）。结论 影像导航下立体定向脑电图定位癫痫病灶在额叶癫痫的外科治疗是安全、有效的。     

The epileptogenic zone

The definition of the epileptogenic zone is a concept proposed by Jean Bancaud and Jean Talairach based on the anatomical, electrical and clinical correlations established from stereoelectroencephalographic recordings. They believed the epileptogenic zone to be the "region of the beginning and the primary organization" of ictal discharges. The opinion of North American authors is different: the epileptogenic zone is the "what to remove area" to produce freedom from seizures. This surgical definition assumes postsurgical validation. The aim of this paper is to show how to define the epileptogenic zone from all the stereoelectroencephalographic recording data.     

立体定向脑电图引导下射频热凝毁损术治疗药物难治性癫痫的有效性分析

目的 分析立体定向脑电图(SEEG)引导下射频热凝毁损术对于治疗药物难治性癫痫的有效性。 方法 将山东大学齐鲁医院癫痫诊疗中心2018年11月至2020年11月收治的14例药物难治性癫痫患者作为研究对象,通过SEEG明确致痫灶,对致痫灶实施SEEG引导下的射频热凝毁损术,分析其有效性及安全性。 结果 14例患者共植入143根电极,根据SEEG结果共热凝50根电极。14例患者热凝后随访2~25个月,平均(8.29±7.90)个月,2例(14.30%)患者术后分别随访3个月及6个月,癫痫无发作为EngelⅠ级;4例(28.57%)患者术后平均随访(3.75±0.50)个月,癫痫发作减少90%以上为EngeⅢ级;5例(35.71%)患者术后平均随访(8.00±6.32)个月,癫痫发作减少50%以上为Engel Ⅲ级;2例(14.30%)患者术后随访25个月癫痫发作减少不足50%,1例(7.10%)热凝后随访2个月发作基本同术前为Engel Ⅳ级。14例患者热凝前后发作频率差异有统计学意义(P=0.001 7),且热凝后的效果随着时间的延长而减退。14例患者热凝后均未出现永久性功能损害。 结论 SEEG引导下的射频热凝毁损术对药物难治性癫痫是一种安全、有效的疗法,影响其有效性的因素较多,它可以有效预测切除手术疗效,对特定类型的癫痫病灶可作为治疗的主要选择。